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Kmu Mdcat 2023 — Solved Past Paper with Answers
All 200 MCQs from Kmu Mdcat 2023, solved with the correct answer highlighted and a full explanation for every question. This is a free MDCAT KPK / ETEA past paper — no signup, no ads. Practise it interactively in timed mode, drill more with free MDCAT MCQs, or browse all KPK / ETEA papers.
Attempt this paper interactively →Q1. I like _ blue T-shirt over there better than _ red one.
- A. No article, the
- B. The, the✓
- C. The, a
- D. A, the
Explanation: The correct answer is Option B: the, the.In the sentence I like the blue T-shirt over there better than the red one., both 'the' articles specify that the speaker is referring to particular items that are already known to both the speaker and listener. The definite article 'the' is used when discussing specific objects. In contrast, the other options are incorrect for the following reasons:Option A fails to provide an article for 'blue T-shirt', making it ambiguous.Option C uses 'the' for 'blue T-shirt' but incorrectly uses 'a' for 'red one', suggesting it's a non-specific item.Option D incorrectly suggests a generic reference for 'blue T-shirt' with 'a', while 'the' for 'red one' is accurate but does not fit the context. Therefore, only Option B correctly conveys the intended meaning.
Why the other options are wrong
- A. This option suggests omitting the article before 'blue T-shirt' and using 'the' before 'red one'. However, without an article, 'blue T-shirt' becomes too vague and does not clearly indicate a specific item.
- C. This option uses 'the' for 'blue T-shirt' and 'a' for 'red one'. While 'the' is correct for the specific blue T-shirt, 'a' implies a non-specific red one, which does not align with the context where both items are already identified.
- D. This option uses 'a' for 'blue T-shirt', which implies a generic blue T-shirt rather than a specific one. This is incorrect since the speaker is referencing a specific blue T-shirt. 'the' for 'red one' is correct, but the combination is not appropriate.
Q2. Choose the correct preposition. All you think and hanker _ is government service.
- A. An
- B. For✓
- C. At
- D. Upon
Explanation: The correct answer is Option B: for. The verb 'hanker' is typically followed by the preposition 'for,' which means to have a strong desire for something. In the sentence, the phrase 'hanker for' indicates that the person has a strong longing for government service, suggesting an obsession with that career path.Option A: 'an' is incorrect because it does not fit the context of expressing desire. Option C: 'at' does not work with 'hanker' and fails to convey the intended meaning. Option D: 'upon' is also incorrect, as it is not used with 'hanker' and does not express the longing that the sentence implies.
Why the other options are wrong
- A. This option is incorrect. The preposition 'an' does not collocate with the verb 'hanker.' It is not used to express desire or longing.
- C. This option is incorrect. The preposition 'at' does not fit with the verb 'hanker' and does not convey the sense of desire expressed in the sentence.
- D. This option is incorrect. The preposition 'upon' is not used in conjunction with 'hanker.' It does not convey the same meaning of desire or longing.
Q3. Choose the correct sentence.
- A. Who isn't here yet asked Parveen.
- B. "Who isn't here yet?" asked Parveen.✓
- C. Who isnt here yet? asked Parveen.
- D. "Who isnt here yet?" asked Parveen.
Explanation: Option B is the correct answer as the punctuation and the format are correct. The basic rules for dialogue include using quotation marks around the spoken words, separating the dialogue from the rest of the text, and including the appropriate punctuation within the question marks.
Why the other options are wrong
- A. This is incorrect as there is no punctuation namely quotation marks and a question mark.
- C. This is incorrect, as there are no quotation marks.
- D. This is incorrect as there is no apostrophe in isn’t
Q4. The director as well as the manager of the hotel _ attending the meeting.
- A. Is✓
- B. are
- C. were
- D. has
Explanation: Option A is correct. The sentence 'The director as well as the manager of the hotel is attending the meeting' uses 'as well as' to connect the subject, but it does not change the singular nature of the first subject, 'the director'. Therefore, the verb should also be singular, which is why 'is' is the correct choice.Options B, C, and D are incorrect because they do not maintain subject-verb agreement with the singular subject 'the director'. 'Are' suggests a plural subject, 'were' indicates past tense and implies a different number, and 'has' does not fit the present continuous form needed in this sentence.
Why the other options are wrong
- B. The verb are is incorrect because the subject preceding 'as well as' is 'the director', which is singular. Therefore, a singular verb is required.
- C. The verb were is incorrect as it implies a plural subject or past tense. In this context, the subject is 'the director', which is singular and requires the present tense singular verb 'is'.
- D. The verb has is not suitable in this context as it does not agree with the subject 'the director' in a present continuous structure. Instead, 'is' fits the structure of the sentence.
Q5. Read the passage and answer the question given at the end.For my 25th birthday, my uncle gave me a gift and to go skydiving at a special place near Miami. I was happy because I wanted to do something wild. On the day of my jump, I could not take breakfast because of the nerves. Before I knew the danger involved in it, I was on the plane with a parachute on my back After the fall, I could feel adrenaline running through me. Then the parachute opened, and I was floating freely like a bird- Those wonderful moments helped me to realize that I am the kind of person who can take risks in life.The author learns from the experience of skydiving that:
- A. Skydiving is dangerous
- B. Miami is a good place for skydiving
- C. He is capable of doing risky things in life✓
- D. Skydiving made him so nervous that he could not take breakfast in the morning
Explanation: Option C is correct because it captures the essence of the author's realization from his skydiving experience. The passage illustrates how the experience led him to understand that he can take risks in life, which is a pivotal conclusion.
Why the other options are wrong
- A. This option identifies a fact about skydiving but does not capture the author's personal growth or realization from the experience.
- B. This option comments on the location but fails to address the author's insights gained from the skydiving experience.
- D. While this option discusses the author's nervousness, it does not articulate any significant personal growth or understanding that he gained from the experience.
Q6. The novice teacher was excited about her first teaching job.[The word closest in meaning to the underlined word is]:
- A. Experienced
- B. Beginner✓
- C. Erudite
- D. Stem
Explanation: Option B is correct.The word closest in meaning to the underlined word novice is beginner. A novice is someone who is new to something, especially a skill or job. A beginner is also someone who is new to something, especially a skill or job.Experienced means having a lot of knowledge and skill from doing something for a long time.Erudite means having a lot of knowledge and learning.Stem is an acronym that stands for science, technology, engineering, and mathematics.
Why the other options are wrong
- A. Experienced means having a lot of knowledge and skill from doing something for a long time. Hence, this is the opposite word for novice.
- C. Erudite means having a lot of knowledge and learning; similar to being experienced.
- D. Stem is an acronym that stands for science, technology, engineering, and mathematics. Therefore, this option is irrelevant.
Q7. Choose the correct spelling:
- A. Entripreneur
- B. Enterpreneur
- C. Entrepreneur✓
- D. Entreprineur
Explanation: The correct spelling is entrepreneur. It refers to a person who sets up a business or businesses, taking on financial risks in the hope of profit.
Why the other options are wrong
- A. Wrong spelling as option C is correct.
- B. Wrong spelling as option C is correct.
- D. Wrong spelling as option C is correct.
Q8. If i were younger, I _ around the world.
- A. Will travel around the world.
- B. Would have travelled
- C. Would travel✓
- D. Travel
Explanation: Option C is correct.The correct answer is would travel. The second conditional tense is used to talk about imaginary or hypothetical situations in the present or future. It is formed using the following structure:If + past tense verb, would + infinitive verbIn the sentence "If I were younger, I _ around the world," the imaginary situation is that the speaker is younger. The speaker is saying that if they were younger, they would travel around the world. The other options are incorrect:Will travel around the world is the future tense, not the second conditional tense.Would have travelled is the third conditional tense, which is used to talk about imaginary or hypothetical situations in the past.Travel is the infinitive verb, not the past tense verb.
Why the other options are wrong
- A. Will travel around the world is the future tense, not the second conditional tense.
- B. Would have travelled is the third conditional tense, which is used to talk about imaginary or hypothetical situations in the past.
- D. Travel is the infinitive verb, not the past tense verb.
Q9. The flower girl sold him flowers.The underlined word is:
- A. Direct Object
- B. Indirect Object✓
- C. Complement
- D. Predicate
Explanation: Option B is correct.The underlined word in the sentence "The flower girl sold him flowers" is an indirect object. An indirect object is the person or thing that receives the direct object of a sentence. The direct object is the person or thing that is acted upon by the verb. In this sentence, the direct object is "flowers" and the indirect object is "him". The indirect object tells us who or what the direct object is being given to. In this case, the flowers are being given to "him".
Why the other options are wrong
- A. A direct object is the receiver of the action of the verb.
- C. A complement is a word or phrase that completes the meaning of a subject or verb.
- D. The predicate of a sentence is everything that comes after the subject and includes the verb and the words governed by it.
Q10. The flower girl sold him flowers.The underlined word is:
- A. Direct object
- B. Indirect object✓
- C. Complement
- D. Predicate
Explanation: “Flowers” is the direct object of the verb “sold,” as it receives the action of selling.The indirect object receives the direct object. “Him” is the indirect object because he receives the flowers.A complement completes the meaning of a verb or adjective. “Flowers” is not a complement here.The predicate contains the verb and tells something about the subject. Here, the predicate is “sold him flowers.”Hence, option B is correct.
Why the other options are wrong
- A. “Flowers” is the direct object of the verb “sold,” as it receives the action of selling.
- C. A complement completes the meaning of a verb or adjective. “Flowers” is not a complement here.
- D. The predicate contains the verb and tells something about the subject. Here, the predicate is “sold him flowers.”
Q11. Identify the past simple tense in the following
- A. We have been reading in the classroom since morning
- B. He had broke this window.
- C. They spoke in Ilrdu to the waitress.✓
- D. She is enjoying the weather on the roof.
Explanation: Option C is correct. It uses the past simple tense, which is used to indicate actions that were completed at a specific time in the past. The sentence 'They spoke in Ilrdu to the waitress' clearly demonstrates this tense. Option A is in the present perfect tense, which describes actions that began in the past and continue to the present, thus not fitting the criteria for past simple. Option B contains a grammatical error with 'broke' instead of 'broken', and while it indicates a past action, it is not in the past simple form. Option D is in the present progressive tense, which indicates an action currently in progress rather than a completed action. Therefore, the only sentence that correctly uses the past simple tense is Option C.
Why the other options are wrong
- A. This sentence is in the present perfect tense, indicating an action that started in the past and continues to the present. It does not represent a completed action in the past.
- B. This sentence attempts to use the past perfect tense, but it contains a grammatical error. The correct form should be 'He had broken this window.' While it refers to a past action, it is not in the past simple tense.
- D. This sentence is in the present progressive tense, indicating an ongoing action. It does not express a completed action in the past, thus it is not the correct answer.
Q12. identify the given clause:Something odd was happening all around the world.
- A. Subordinate clause
- B. Independent clause✓
- C. Dependent clause
- D. Relative clause
Explanation: Option B is correct. It is an independent clause because an independent clause can form a complete sentence on its own, containing a subject and a predicate. In the given clause, 'something odd' serves as the subject, while 'was happening all around the world' serves as the predicate, thus making it a complete thought.
Why the other options are wrong
- A. A subordinate clause cannot stand alone as a complete sentence. It relies on a main clause for its meaning. In this case, 'something odd was happening all around the world' can stand alone, so this option is incorrect.
- C. A dependent clause cannot stand alone as a complete thought and needs an independent clause to provide context. Since the given clause can stand alone, this option is incorrect.
- D. A relative clause typically begins with a relative pronoun (like 'who', 'that', or 'which') and provides additional information about a noun. Since the clause in question does not fit this definition, this option is incorrect.
Q13. We met rather few people who spoke English.The sentence is:
- A. Complex✓
- B. Simple
- C. Compound
- D. Compound complex
Explanation: Option A is correct. A complex sentence is defined as having one independent clause and at least one dependent clause. In this case, "we met rather few people" is the independent clause, and "who spoke English" is the dependent clause that provides additional detail. Option B is incorrect because a simple sentence contains only an independent clause with no dependent clauses. Option C is incorrect as a compound sentence requires at least two independent clauses. The provided sentence contains only one. Option D is incorrect since a compound-complex sentence needs at least two independent clauses along with one dependent clause, which this sentence does not have.
Why the other options are wrong
- B. A simple sentence contains only one independent clause and no dependent clauses. The given sentence includes a dependent clause, thus it cannot be classified as simple.
- C. A compound sentence consists of two or more independent clauses joined by a coordinating conjunction. This sentence has only one independent clause, making it incorrect to classify it as compound.
- D. A compound-complex sentence contains at least two independent clauses and at least one dependent clause. The sentence in question only has one independent clause, so it does not meet the criteria for this type.
Q14. Identify the sentence with correct punctuation and capitalization.
- A. The automobile dealer handled three makes of cars: Toyota, Suzuki, and Honda.✓
- B. The automobile dealer handled three makes of cars, Toyotas, Suzuki, and Honda.
- C. The automobile dealer handled three makes of cars Toyota, Suzuki, and Honda.
- D. The automobile dealer handled three makes of cars, Toyota, Suzuki, and Handa.
Explanation: Option A is correct because it appropriately uses a colon to introduce the list of car brands and capitalizes proper nouns accurately. The colon is essential here as it signals that what follows is a list related to the preceding clause.Option B is incorrect because it pluralizes 'Toyota' as 'Toyotas', which is not the proper way to refer to car makes in this context.Option C is incorrect due to the absence of punctuation. A colon is needed to clarify that a list follows, making the sentence grammatically flawed.Option D is incorrect because it contains a factual error: 'Honda' is misspelled as 'Handa', even though the punctuation is correctly placed.
Why the other options are wrong
- B. This option incorrectly pluralizes 'Toyota' as 'Toyotas', which is not standard when listing car makes.
- C. This option lacks punctuation after "cars" to introduce the list, making it grammatically incorrect.
- D. This option incorrectly uses 'Handa' instead of 'Honda', making it a factual error, even though the punctuation is correct.
Q15. Which of the following sentences is in correct order?
- A. We up right drove to Karachi in two days.
- B. We to Karachi drove in two days right up.
- C. We right drove to Karachi up in two days.
- D. We drove right up to Karachi in two days.✓
Explanation: Option D is the only correct sentence structure. The rest are grammatically incorrect.The first sentence, "We up right drove to Karachi in two days," is grammatically incorrect because it places the adverb "right" before the verb "drove." Adverbs should typically be placed after the verb they modify.The second sentence, "We to Karachi drove in two days right up," is awkward because it places the prepositional phrase "to Karachi" between the auxiliary verb "drove" and the main verb "up." Prepositional phrases should typically be placed at the end of a sentence.The third sentence, "We right drove to Karachi up in two days," is awkward because it places the adverb "up" after the prepositional phrase "to Karachi." Adverbs should typically be placed before prepositional phrases.The fourth sentence, "We drove right up to Karachi in two days," is the only sentence that is both grammatically correct and natural-sounding. It clearly states that the speaker and their companions drove to Karachi in two days, and that they arrived there quickly and directly
Why the other options are wrong
- A. "We up right drove to Karachi in two days," is grammatically incorrect because it places the adverb "right" before the verb "drove." Adverbs should typically be placed after the verb they modify.
- B. "We to Karachi drove in two days right up," is awkward because it places the prepositional phrase "to Karachi" between the auxiliary verb "drove" and the main verb "up." Prepositional phrases should typically be placed at the end of a sentence.
- C. "We right drove to Karachi up in two days," is awkward because it places the adverb "up" after the prepositional phrase "to Karachi." Adverbs should typically be placed before prepositional phrases.
Q16. You can either come with me now nor walk home later.The word which does not fit in the sentence correct order is:
- A. Can
- B. Either come
- C. Now
- D. Nor✓
Explanation: Option D is correct. The sentence uses 'either' but incorrectly pairs it with 'nor' instead of 'or'. The correct conjunctions would be 'either/or' or 'neither/nor'. Therefore, 'nor' does not fit in the sentence.Options A, B, and C are incorrect because they do not disrupt the grammatical integrity of the sentence. 'Can', 'either come', and 'now' can all be part of a grammatically correct sentence, while 'nor' creates a mismatch in conjunction pairing.
Why the other options are wrong
- A. This option does not disrupt the grammatical structure of the sentence. 'Can' is a modal verb that fits well with the rest of the sentence.
- B. This phrase is part of the correct conjunction structure, but the placement of 'nor' is problematic in the sentence.
- C. 'Now' is an adverb indicating time and does not interfere with the sentence structure. Therefore, it is not the correct choice.
Q17. Find one error in the sentence, if any. I just don't want to get out off bed today.
- A. Get out
- B. Just
- C. Off✓
- D. No error
Explanation: In the sentence 'I just don't want to get out off bed today,' the error lies in the use of the word 'off.' The correct preposition should be 'of,' making the correct sentence: 'I just don't want to get out of bed today.' The preposition 'out' is usually followed by 'of' when indicating movement from a container or location, such as a bed. Therefore, the speaker is expressing a desire to remain in bed, which is a type of container. The other options are incorrect because they either point out words that do not contain errors or claim that the sentence has no errors at all.
Why the other options are wrong
- A. This option is incorrect. The phrase 'get out' itself is not the issue; rather, the problem lies in the preposition that follows it.
- B. This option is incorrect. The word 'just' does not contain an error in this sentence; it is used correctly to express the speaker's feelings.
- D. This option is incorrect. There is indeed an error in the sentence, specifically the misuse of the preposition 'off' instead of 'of.'
Q18. Read the passage and answer the questions given at the end;Efforts should be made to control the use of tobacco in the campuses of educational institutions because it is gateway to drug abuse. Most of the youth usually starts with soft drugs like cigarettes, chhaliya, gutka. naswar and pan, and then move to hard drugs like heroin, opium, cocaine, ke and sheesha, etc. People who start-smoking cigarettes of drink alcohol at a young age are much more likely to experiment with illegal drugs than people who do not smoke of drink.According to this paragraph
- A. Educational institutions are gateways to the control of tobacco
- B. Youth who starts with soft drugs are likely to experiment with illegal drugs
- C. People who do not smoke or drink are less-likely, to experiment with illegal drugs✓
- D. People who start smoking at a young age are less likely to experiment with illegal drugs
Explanation: Option C is most appropriate according to the last line of the passage that "people who do not smoke or drink" are less likely to experiment with drugs.
Why the other options are wrong
- A. Option A is incorrect because the passage mentions "the use of tobacco in educational campuses are gateways to drug abuse", not educational campuses themselves.
- B. While option B is not entirely wrong, it is incorrect because according to the exact wording of the passage youths usually start with soft drugs, and then move to "hard drugs", not illegal drugs,
- D. Option D is incorrect because young smokers are "more likely" to experiment with Illegal drugs according to the passage, not less likely,
Q19. Smoking cigarettes or drinking alcohol leads to:
- A. Legal drugs
- B. Illegal drugs✓
- C. Soft drugs
- D. The use of tobacco in educational institutions
Explanation: Option B is correct. The passage indicates that individuals who smoke cigarettes and drink alcohol often find themselves using illegal drugs. This connection highlights the concern around the escalation of substance use. Option A (legal drugs) is incorrect because the question implies a transition to more harmful substances, not those that are legally sanctioned. Option C (soft drugs) also fails to capture the severity of the situation described in the passage, as soft drugs are typically less dangerous than illegal drugs. Option D (The use of tobacco in educational institutions) is not relevant to the question's main focus on the relationship between smoking, drinking, and illegal drug use.
Why the other options are wrong
- A. This option refers to substances that are permitted and regulated by law. However, the context implies that smoking and drinking lead to more severe substance use, making this option incorrect.
- C. This term typically refers to substances that are less harmful and often legal in some contexts. However, the question's context indicates a progression towards more dangerous illegal drugs, making this option incorrect.
- D. This option is unrelated to the question's focus on the progression from smoking and drinking to drug use. It doesn't address the core issue of illegal drug use, so it is incorrect.
Q20. Which of the following statements Is not correct about alveoli:
- A. Alveoli form the gas exchange surface
- B. The wall of each alveolus is 0.1 cm thick✓
- C. Alveoli has a dense network of capillaries
- D. Collagen and elastin present in alveoli allow it to expand and recoil easily during breathing
Explanation: Option B regarding alveoli is not correct.The walls of alveoli are extremely thin, only about 0.0002 cm thick. This allows for the rapid diffusion of gases between the alveoli and the blood capillaries that surround them.while all other statements regarding alveoli are correct.
Why the other options are wrong
- A. Yes, the alveoli form the gas exchange surface in the lungs. The alveoli are tiny air sacs that are surrounded by blood vessels called capillaries. The walls of the alveoli and capillaries are very thin, which allows oxygen and carbon dioxide to diffuse across them.Oxygen diffuses from the alveoli into the blood because the concentration of oxygen is higher in the alveoli. Carbon dioxide diffuses from the blood into the alveoli because the concentration of carbon dioxide is higher in the blood.
- C. Yes, the alveoli have a dense network of capillaries. This dense network of capillaries allows for a lot of gas exchange to occur between the alveoli and the blood. There are about 300 million alveoli in the lungs and each alveolus is surrounded by about 1,000 capillaries. This means that there are about 300 billion capillaries in the lungs.
- D. Yes, collagen and elastin present in alveoli allow it to expand and recoil easily during breathing. The alveoli are small, air sacs in the lungs that are responsible for gas exchange. The walls of the alveoli are made up of a thin layer of cells and collagen and elastin fibers. Collagen is a protein that provides strength and structure to the alveoli. Elastin is a protein that allows the alveoli to stretch and recoil.
Q21. Which of the following connective tissues consists of cells known as chondrocytes?
- A. Myocardium
- B. Cartilage✓
- C. Bone
- D. Periosteum
Explanation: Option B is correct. The connective tissue that consists of cells known as chondrocytes is cartilage. Chondrocytes are the only type of cell found in cartilage. They are responsible for producing and maintaining the extracellular matrix of cartilage, which is made up of collagen, elastin, and proteoglycans. Myocardium is the muscle tissue of the heart. It contains muscle cells, also known as cardiomyocytes. Bone is a type of connective tissue that is made up of a hard, mineralized matrix. It contains osteocytes, which are bone cells that are responsible for maintaining the bone matrix. Periosteum is a tough, fibrous membrane that covers the outer surface of bones. It contains fibroblasts, which are cells that produce collagen and other extracellular matrix proteins.
Why the other options are wrong
- A. Myocardium is the muscle tissue of the heart. It contains muscle cells, also known as cardiomyocytes.
- C. Bone is a type of connective tissue that is made up of a hard, mineralized matrix. It contains osteocytes, which are bone cells that are responsible for maintaining the bone matrix.
- D. Periosteum is a tough, fibrous membrane that covers the outer surface of bones. It contains fibroblasts, which are cells that produce collagen and other extracellular matrix proteins.
Q22. The joint present between wrist bones is;
- A. Fibrous joint
- B. Cartilaginous joint /sliding joint✓
- C. Hinge joint
- D. Ball and socket joint
Explanation: Option B is correct. The joint between wrist bones is a cartilaginous joint. Cartilaginous joints are slightly movable joints that are connected by cartilage. The cartilage acts as a cushion and helps to reduce friction between the bones. Cartilaginous joints are found throughout the body, including in the spine, pelvis, and ribs. They are also found in the joints between the skull bones. Fibrous joints are immovable joints that are connected by fibrous connective tissue. Fibrous joints are found in the skull and pelvis. Hinge joints are slightly movable joints that allow for movement in one plane. Hinge joints are found in the elbows, knees, and fingers. Ball and socket joints are freely movable joints that allow for movement in all planes. Ball and socket joints are found in the hips, shoulders, and head of the thighbone.
Why the other options are wrong
- A. Fibrous joints are immovable joints that are connected by fibrous connective tissue. Fibrous joints are found in the skull and pelvis.
- C. Hinge joints are slightly movable joints that allow for movement in one plane. Hinge joints are found in the elbows, knees, and fingers.
- D. Ball and socket joints are freely movable joints that allow for movement in all planes. Ball and socket joints are found in the hips, shoulders, and head of the thighbone.
Q23. The sarcomere is the region of a myofibril between two successive:
- A. I-Line
- B. A-Line
- C. Z-Line✓
- D. M-Line
Explanation: Option C is correct. The sarcomere is the region of a myofibril between two successive Z-lines. A myofibril is a long, thin strand of muscle tissue that is made up of sarcomeres. Sarcomeres are the basic contractile units of muscle tissue. The Z-line is a thin, dark line that marks the boundary of a sarcomere. It is made up of a protein called α-actinin, which helps to anchor the actin filaments in place. I-band: The I-band is the light-colored band in the sarcomere. It contains only actin filaments. A-band: The A-band is the dark-colored band in the sarcomere. It contains both actin and myosin filaments. M-line: The M-line is a thin line in the center of the A-band. It is made up of a protein called myomesin, which helps to stabilize the myosin filaments.
Why the other options are wrong
- A. I-band: The I-band is the light-colored band in the sarcomere. It contains only actin filaments.
- B. A-band: The A-band is the dark-colored band in the sarcomere. It contains both actin and myosin filaments.
- D. M-line: The M-line is a thin line in the center of the A-band. It is made up of a protein called myomesin, which helps to stabilize the myosin filaments.
Q24. The size of a synaptic cleft (the gap separating nerve cells) in electrical synapse is
- A. 0.2 nm✓
- B. 2 nm
- C. 20 nm
- D. 200 nm
Explanation: Option A is correct. The size of a synaptic cleft in an electrical synapse is typically 0.2 nm, which is much smaller compared to the synaptic cleft of chemical synapses, which ranges from 20 to 40 nm. This small size is crucial because it allows ions and small molecules to pass quickly between the two cells through gap junctions, facilitating rapid electrical signal transmission. Conversely, Option B (2 nm) and Option C (20 nm) are incorrect as they exceed the actual size of the cleft in electrical synapses, which would hinder the speed of signal transmission. Option D (200 nm) is also incorrect, being significantly larger than the typical size, and does not represent the characteristics of electrical synapses.
Why the other options are wrong
- B. This option is larger than the typical size of a synaptic cleft in an electrical synapse, which is 0.2 nm. Electrical synapses are characterized by their very narrow gaps for efficient signal transmission.
- C. This size is more representative of a chemical synapse rather than an electrical synapse, where the cleft is usually 0.2 nm. Therefore, this option is incorrect.
- D. 200 nm is significantly larger than the typical synaptic cleft size in electrical synapses, which is 0.2 nm. This option is not correct as it does not reflect the characteristics of electrical synapses.
Q25. The activities like sleeping, walking, and dreaming are controlled by which part of the brain:
- A. Pons✓
- B. Cerebellum
- C. Olfactory bulb
- D. Hippocampus
Explanation: The activities like sleeping, walking, and dreaming are controlled by the pons. The pons is a small but important part of the brain that is located in the brainstem. It is involved in a variety of functions, including: 1. Sleep-wake cycle: The pons helps to regulate the sleep-wake cycle by controlling the production of melatonin, a hormone that is involved in sleep regulation. 2. Motor control: The pons helps to coordinate the movement of the eyes, face, and tongue. It also helps to control the muscles that are involved in breathing and swallowing. 3. Sensory processing: The pons helps to process sensory information from the body, including information from the ears, nose, and tongue. The cerebellum, olfactory bulb, and hippocampus are three important parts of the brain with distinct functions.
Why the other options are wrong
- B. Cerebellum 1. Motor coordination: The cerebellum helps to coordinate the movement of muscles throughout the body. This includes movements such as walking, running, and reaching for objects. 2. Balance and equilibrium: The cerebellum helps to maintain balance and equilibrium. This is important for activities such as walking, running, and standing upright. 3. Learning and memory: The cerebellum is also involved in learning and memory, particularly motor learning. This is the process of learning new skills and movements, such as playing a sport or learning to play a musical instrument. 4. Cognitive function: The cerebellum is also thought to play a role in cognitive function, such as attention, planning, and decision-making.
- C. Olfactory bulb 1. Processing of smell: The olfactory bulb is the first part of the brain to process smells. It receives signals from the olfactory receptors in the nose and sends those signals to the rest of the brain. 2. Memory formation and consolidation: The olfactory bulb is also involved in memory formation and consolidation, particularly odor-related memories.3.Emotion regulation: The olfactory bulb is also thought to be involved in emotion regulation. This is because smell is closely linked to emotions, such as fear, pleasure, and disgust.
- D. The hippocampus is a complex brain structure in the medial temporal lobe that is crucial for forming and storing new long-term memories, particularly spatial and episodic memories.
Q26. The hormone 'calcitonin' is secreted by:
- A. Thyroid gland✓
- B. Parathyroid gland
- C. Pancreas
- D. Adrenal gland
Explanation: Option A is correct. The hormone calcitonin is secreted by the thyroid gland. The thyroid gland is a small, butterfly-shaped gland located in the neck. It is responsible for producing hormones that regulate metabolism, growth, and development, and body temperature. Calcitonin is a hormone that helps to regulate calcium levels in the blood. It works by inhibiting the activity of osteoclasts, which are cells that break down bone. This helps to prevent calcium from being released into the blood from bone. Calcitonin also helps to increase the excretion of calcium in the urine. This also helps to lower calcium levels in the blood. The other options are not involved in the secretion of calcitonin: Parathyroid gland: The parathyroid gland produces parathyroid hormone, which is a hormone that helps to raise calcium levels in the blood. Pancreas: The pancreas produces insulin and glucagon, which are hormones that regulate blood sugar levels. Adrenal gland: The adrenal gland produces hormones such as cortisol, adrenaline, and aldosterone, which are involved in a variety of functions, including stress response, metabolism, and blood pressure regulation.
Why the other options are wrong
- B. Parathyroid gland: The parathyroid gland produces parathyroid hormone, which is a hormone that helps to raise calcium levels in the blood.
- C. Pancreas: The pancreas produces insulin and glucagon, which are hormones that regulate blood sugar levels.
- D. Adrenal gland: The adrenal gland produces hormones such as cortisol, adrenaline, and aldosterone, which are involved in a variety of functions, including stress response, metabolism, and blood pressure regulation.
Q27. Fallopian tube is also known as:
- A. Oviduct✓
- B. Ovaries
- C. Uterus
- D. Cervix
Explanation: Option A is correct.Fallopian tube is also known as oviduct.Fallopian tubes are muscular tubes that connect the ovaries to the uterus. They transport eggs from the ovaries to the uterus, where they can be fertilized by sperm. If an egg is fertilized, it begins to travel down the fallopian tube to the uterus, where it implants and grows into a fetus. Fallopian tubes are essential for conception. If the fallopian tubes are blocked or damaged, it can make it difficult or impossible for a woman to get pregnant. Ovaries: The ovaries are two small, oval-shaped glands located on either side of the uterus. They are responsible for producing eggs (also called ova) and hormones, such as estrogen and progesterone.Uterus: The uterus is a hollow, pear-shaped organ located in the lower abdomen. It is where a fertilized egg implants and grows into a fetus. The uterus is also responsible for menstruation, which is the monthly shedding of the lining of the uterus if a fertilized egg does not implant. Cervix: The cervix is the narrow opening at the bottom of the uterus that leads to the vagina. It produces mucus, which helps to protect the uterus from infection and sperm. The cervix also dilates and opens during childbirth to allow the baby to pass through.
Why the other options are wrong
- B. Ovaries: The ovaries are two small, oval-shaped glands located on either side of the uterus. They are responsible for producing eggs (also called ova) and hormones, such as estrogen and progesterone.
- C. Uterus: The uterus is a hollow, pear-shaped organ located in the lower abdomen. It is where a fertilized egg implants and grows into a fetus. The uterus is also responsible for menstruation, which is the monthly shedding of the lining of the uterus if a fertilized egg does not implant.
- D. Cervix: The cervix is the narrow opening at the bottom of the uterus that leads to the vagina. It produces mucus, which helps to protect the uterus from infection and sperm. The cervix also dilates and opens during childbirth to allow the baby to pass through.
Q28. The syphillis is a _ disease.
- A. Bacterial✓
- B. Fungal
- C. Protozoic
- D. Viral
Explanation: Option A is correct.Syphilis is a bacterial disease. It is caused by the bacterium Treponema pallidum. Syphilis is a sexually transmitted infection (STI) that can also be transmitted from mother to child during pregnancy or childbirth. Bacterial diseases are caused by bacteria. Bacteria are microscopic organisms that can cause a variety of diseases, including pneumonia, strep throat, and urinary tract infections.Fungal diseases are caused by fungi. Fungi are microscopic organisms that can cause a variety of diseases, including athlete's foot, ringworm, and candidiasis.Protozoan diseases are caused by protozoa. Protozoa are microscopic organisms that can cause a variety of diseases, including malaria, giardiasis, and toxoplasmosis.Viral diseases are caused by viruses. Viruses are microscopic organisms that can cause a variety of diseases, including the common cold, influenza, and HIV/AIDS.
Why the other options are wrong
- B. Fungal diseases are caused by fungi. Fungi are microscopic organisms that can cause a variety of diseases, including athlete's foot, ringworm, and candidiasis.
- C. Protozoan diseases are caused by protozoa. Protozoa are microscopic organisms that can cause a variety of diseases, including malaria, giardiasis, and toxoplasmosis.
- D. Viral diseases are caused by viruses. Viruses are microscopic organisms that can cause a variety of diseases, including the common cold, influenza, and HIV/AIDS.
Q29. The most common symptom of gonorrhea in male is:
- A. Skin rash on neck
- B. Joint pain
- C. Painful urination✓
- D. Chancre
Explanation: Option C is correct.The most common symptom of gonorrhea in males is painful urination. Other symptoms of gonorrhea in males can include;White, yellow, or green discharge from the penisPainful or swollen testiclesRedness and inflammation at the opening of the penisGonorrhea is a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. It can infect the urethra, rectum, and throat. Gonorrhea can be treated with antibiotics, but if left untreated, it can lead to serious health problems, such as infertility and pelvic inflammatory disease (PID).The other options are not the most common symptoms of gonorrhea in males:Skin rash on neck: A skin rash on the neck is not a typical symptom of gonorrhea.Joint pain: Joint pain can be a symptom of gonorrhea, but it is not the most common symptom.Chancre: A chancre is a small, round ulcer that can be a sign of syphilis, another STI.
Why the other options are wrong
- A. Skin rash on neck: A skin rash on the neck is not a typical symptom of gonorrhea.
- B. Joint pain: Joint pain can be a symptom of gonorrhea, but it is not the most common symptom.
- D. Chancre: A chancre is a small, round ulcer that can be a sign of syphilis, another STI.
Q30. G.J Mendel chose _ as an experimental plant for his study
- A. Medicago sativa
- B. Piscum Sativum✓
- C. Delonicx regia
- D. Lens Culinaris
Explanation: Option B is coorect.G.J Mendel chose Pisum sativum, the garden pea plant, as an experimental plant for his study.Mendel chose pea plants because they have a number of characteristics that make them ideal for studying inheritance:1.They have a short life cycle, so Mendel could study multiple generations of plants in a relatively short period of time.2.They produce a large number of seeds, which gave Mendel a large sample size to work with.3.They have a variety of easily observable traits, such as seed color, flower color, and plant height.4.They are relatively easy to cross-pollinate, which allowed Mendel to control the inheritance of traits.Mendel's experiments with pea plants led to the discovery of the basic laws of inheritance, which are still taught in biology classrooms today.The other options are not plants that Mendel used in his experiments:Medicago sativa is alfalfa, a legume plant that is used as forage for livestock.Delonix regia is the flamboyant tree, a flowering tree that is native to Madagascar.Lens culinaris is the lentil, a legume plant that is grown for its edible seeds.
Why the other options are wrong
- A. Medicago sativa is alfalfa, a legume plant that is used as forage for livestock.
- C. Delonix regia is the flamboyant tree, a flowering tree that is native to Madagascar.
- D. Lens culinaris is the lentil, a legume plant that is grown for its edible seeds.
Q31. When round and yellow color seeded plant (RrYy) is self-crossed the number of plants with rounds and yellow color seeds obtained is _ in 32 plants:
- A. 18✓
- B. 9
- C. 3
- D. 1
Explanation: Option A is correct.When a round and yellow seeded plant (RrYy) is self-crossed, the expected phenotypic ratio of the offspring is 9:3:3:1. In this ratio, 9 represents the plants with round and yellow seeds. To find the number of these plants in a total of 32, you can calculate:(9/16) * 32 = 18.This indicates that out of 32 plants, we expect 18 to exhibit the round and yellow phenotype. The other options are incorrect because they do not accurately reflect the expected ratios from a dihybrid cross. Option B (9) represents only a fraction of the expected round and yellow plants; Option C (3) and Option D (1) both underestimate the number of plants based on the Mendelian inheritance ratios. Thus, they do not align with the expected outcomes of the genetic cross.
Why the other options are wrong
- B. This option represents the expected number of round and yellow seeds if only one round and yellow seed plant were crossed, which is incorrect. The calculation should consider the ratios from a dihybrid cross.
- C. This number does not correspond to any expected outcome from the self-cross of a dihybrid plant. There are more round and yellow seeds expected in the offspring based on the 9:3:3:1 ratio.
- D. This option is also incorrect as it significantly underestimates the number of round and yellow seeds that can be produced from a dihybrid cross. The expected outcome is much higher due to the ratios involved.
Q32. In crossing over, the exchange of maternal and paternal chromatids occurs while homologous chromosomes are paired during:
- A. Prophase meiosis I✓
- B. Prophase meiosis II
- C. Metaphase of meiosis I
- D. Anaphase meiosis II
Explanation: Option A is correct. Crossing over occurs during prophase I of meiosis I, when homologous chromosomes pair up and exchange segments of their genetic material, leading to genetic variation in the offspring. In contrast, Option B is incorrect because prophase II occurs after the homologous chromosomes have been separated, and no crossing over takes place. Option C is also incorrect; during metaphase I, homologous chromosomes align but do not exchange genetic material. Lastly, Option D is incorrect as anaphase II focuses solely on the separation of sister chromatids, with no involvement of crossing over.
Why the other options are wrong
- B. This option is incorrect. Prophase II involves the preparation of the chromosomes for separation but does not involve crossing over, as the homologous pairs have already separated.
- C. This option is incorrect. In metaphase I, homologous chromosomes align at the cell's equator but do not exchange genetic material. Crossing over occurs earlier, specifically in prophase I.
- D. This option is incorrect. Anaphase II involves the separation of sister chromatids and does not involve crossing over, which occurs in prophase I.
Q33. Drosophila Melanogaster is the scientific name of:
- A. House fly
- B. Fruit fly✓
- C. Flash fly
- D. Sand fly
Explanation: Option B is correct.Drosophila Melanogaster is the scientific name of the fruit fly. It is a small fly that is commonly found in homes and restaurants. Fruit flies are attracted to ripe fruit and decaying organic matter. The other options are not the scientific names of the fruit fly:House fly: The scientific name of the house fly is Musca domestica.Flash fly: The scientific name of the flash fly is Phoridae.Sand fly: The scientific name of the sand fly is Phlebotominae.
Why the other options are wrong
- A. House fly: The scientific name of the house fly is Musca domestica.
- C. Flash fly: The scientific name of the flash fly is Phoridae.
- D. Sand fly: The scientific name of the sand fly is Phlebotominae.
Q34. A condition that renders the individual less able to form blood clots is:
- A. Alports syndrome
- B. Coffin-Lowry syndrome
- C. Hemophilia✓
- D. Thalassemia
Explanation: Option C is correct.Hemophilia is a condition that renders the individual less able to form blood clots. It is a genetic disorder that affects the blood's ability to clot. People with hemophilia have low levels of clotting factors, which are proteins that help the blood to clot. This can lead to excessive bleeding, even from minor injuries.Hemophilia is a serious condition, but it can be managed with treatment. There are two types of hemophilia: hemophilia A and hemophilia B. Hemophilia A is the most common type of hemophilia. It is caused by a deficiency in clotting factor VIII. Hemophilia B is less common than hemophilia A. It is caused by a deficiency in clotting factor IX.Treatment for hemophilia typically involves replacing the missing clotting factor with infusions. This can be done as needed to stop bleeding or on a regular basis to prevent bleeding. The other options are not conditions that render the individual less able to form blood clots:Alport syndrome is a genetic disorder that affects the kidneys, eyes, and ears.Coffin-Lowry syndrome is a genetic disorder that causes intellectual disability, short stature, and distinctive facial features.Thalassemia is a genetic disorder that affects the production of hemoglobin, the protein in red blood cells that carries oxygen.
Why the other options are wrong
- A. Alport syndrome is a genetic disorder that affects the kidneys, eyes, and ears.
- B. Coffin-Lowry syndrome is a genetic disorder that causes intellectual disability, short stature, and distinctive facial features.
- D. Thalassemia is a genetic disorder that affects the production of hemoglobin, the protein in red blood cells that carries oxygen.
Q35. Intra-specific struggle refers to:
- A. Competition between members of the same species✓
- B. Competition between members of the different species
- C. Environmental struggle
- D. Prey or predation
Explanation: Option A is correct. Intra-specific struggle refers to competition between members of the same species. This can include competition for food, water, mates, and territory. Intra-specific struggle is a very important factor in natural selection, as it helps to ensure that only the fittest individuals survive and reproduce. Intra-specific struggle can be very intense, as the individuals involved are all very similar and have the same needs. This can lead to aggression, fighting, and even death. However, intra-specific struggle can also have positive benefits, such as driving innovation and promoting cooperation. The other options are not correct: Competition between members of different species is called interspecific struggle. Environmental struggle is the competition between organisms of a population against one another in nature to maintain themselves in a given environment to survive and reproduce. Prey or predation is the interaction between two species, where one species captures and kills the other for food.
Why the other options are wrong
- B. Competition between members of different species is called interspecific struggle.
- C. Environmental struggle is the competition between organisms of a population against one another in nature to maintain themselves in a given environment to survive and reproduce.
- D. Prey or predation is the interaction between two species, where one species captures and kills the other for food.
Q36. Identify fossil bird among the following:
- A. Equus
- B. Python
- C. Archaeopteryx✓
- D. Dawn horse
Explanation: The correct answer is Archaeopteryx, which is a significant fossil in the study of evolution as it exhibits both avian and non-avian characteristics. This makes it a key piece of evidence for the transition from dinosaurs to modern birds.The other options are incorrect for the following reasons: Equus is associated with horses and is a mammal, Python is a genus of snakes, and Dawn horse is a type of ancient horse. None of these represent fossil birds, highlighting the unique position of Archaeopteryx in the fossil record.
Why the other options are wrong
- A. Equus refers to the genus that includes modern horses, donkeys, and zebras. It is not a bird but a mammal.
- B. Python is a genus of snakes, which are reptiles. Snakes are not considered birds, and thus this option is incorrect.
- D. Dawn horse refers to an extinct genus of horse that existed in the Eocene epoch. While it is a fossil, it is not a bird.
Q37. Which of the following organelle is regarded as self-replicable organelle
- A. Endoplasmic reticulum
- B. Golgi bodies
- C. Mitochondria✓
- D. Vacoule
Explanation: Option C is correct.Mitochondria are regarded as self-replicating organelles. They have their own DNA and can replicate independently of the nucleus. This means that they can divide and reproduce independently, without the assistance of other organelles.Mitochondria are essential for energy production in the cell. They convert food into energy in the form of ATP, which is the cell's energy currency. Mitochondria are also involved in other cellular processes, such as cell signaling and apoptosis (programmed cell death).The endoplasmic reticulum (ER) is not regarded as a self-replicating organelle because it does not have its own DNA. DNA is required for self-replication, as it contains the instructions for building new organelles. The ER is a network of membranes that is involved in the production and transport of proteins and lipids. It is made up of two types of membranes: the rough ER and the smooth ER. The rough ER is covered in ribosomes, which are the organelles that synthesize proteins. The smooth ER is involved in the production of lipids and the detoxification of drugs and toxins. Golgi bodies are also not self-replicating organelles. Golgi bodies are involved in the processing and packaging of proteins and lipids for transport to other parts of the cell. Vacuoles are not self-replicating organelles. Vacuoles are storage organelles that can contain water, salts, and other molecules.
Why the other options are wrong
- A. The endoplasmic reticulum (ER) is not regarded as a self-replicating organelle because it does not have its own DNA. DNA is required for self-replication, as it contains the instructions for building new organelles. The ER is a network of membranes that is involved in the production and transport of proteins and lipids. It is made up of two types of membranes: the rough ER and the smooth ER. The rough ER is covered in ribosomes, which are the organelles that synthesize proteins. The smooth ER is involved in the production of lipids and the detoxification of drugs and toxins.
- B. Golgi bodies is also not self-replicating organelles. Golgi bodies are involved in the processing and packaging of proteins and lipids for transport to other parts of the cell.
- D. Vacuoles is not self-replicating organelles. Vacuoles are storage organelles that can contain water, salts, and other molecules.
Q38. The prokaryotic cell wall is composed of:
- A. Cellulose
- B. Chitin
- C. Murein✓
- D. Pectin
Explanation: Option C is correct.The prokaryotic cell wall is composed of murein, also known as peptidoglycan. Murein is a polymer made up of two sugar molecules and a short peptide chain. It is a very strong and rigid material that helps to protect the cell from osmotic lysis and other environmental stresses.Cellulose is a polymer of glucose molecules that is found in the cell walls of plants. Chitin is a polymer of N-acetylglucosamine molecules that is found in the exoskeletons of insects and other invertebrates. Pectin is a polymer of galacturonic acid molecules that is found in the cell walls of plants.
Why the other options are wrong
- A. Cellulose is a polysaccharide made of β-glucose units linked by β-1,4-glycosidic bonds, forming a rigid structure that provides strength and support to plant cell walls.
- B. Chitin is a long-chain polymer of N-acetylglucosamine units, providing structural strength and protection in the exoskeletons of insects, crustaceans, and other invertebrates, as well as in fungal cell walls.
- D. Pectin is a polysaccharide composed mainly of galacturonic acid units, and it is found in plant cell walls where it helps bind cells together and provides rigidity and stability to the tissue.
Q39. _ is found in the exoskeleton of crabs
- A. cellulose
- B. chitin✓
- C. murein
- D. hemi-cellulose
Explanation: Option B is correct. Chitin is found in the exoskeleton of crabs. Chitin is a tough, fibrous material that is made up of long chains of sugar molecules. It is the main component of the exoskeletons of insects, spiders, crabs, and other invertebrates. Chitin is also found in the cell walls of fungi and some algae. The other options are not found in the exoskeleton of crabs: Cellulose is a tough, fibrous material that is made up of long chains of sugar molecules. It is the main component of the cell walls of plants. Murein is a polymer made up of two sugar molecules and a short peptide chain. It is the main component of the cell walls of bacteria. Hemicellulose is a polymer of sugar molecules that is found in the cell walls of plants.
Why the other options are wrong
- A. Cellulose is a tough, fibrous material that is made up of long chains of sugar molecules. It is the main component of the cell walls of plants.
- C. Murein is a polymer made up of two sugar molecules and a short peptide chain. It is the main component of the cell walls of bacteria.
- D. Hemicellulose is a polymer of sugar molecules that is found in the cell walls of plants.
Q40. Choose the unsaturated fatty acid among the following:
- A. Palmitic acid
- B. Archachidic acid
- C. Stearic acid
- D. Oleic acid✓
Explanation: Option D is correct. Oleic acid is the unsaturated fatty acid. Fatty acids are classified into saturated and unsaturated fatty acids. Saturated fatty acids do not have any double bonds between the carbon atoms in their chain, while unsaturated fatty acids have at least one double bond. Unsaturated fatty acids are considered to be healthier than saturated fatty acids because they can help to lower cholesterol levels and reduce the risk of heart disease. Oleic acid is a monounsaturated fatty acid, which means that it has one double bond in its chain. It is the most common monounsaturated fatty acid in the human diet and is found in many plant-based oils, such as olive oil and avocado oil. The other options are saturated fatty acids:Palmitic acid is a long-chain saturated fatty acid that is found in many animal products, such as meat, butter, and cheese. Arachidic acid is a long-chain saturated fatty acid that is found in peanuts, peanut oil, and chocolate. Stearic acid is a long-chain saturated fatty acid that is found in beef, lamb, and cocoa butter.
Why the other options are wrong
- A. Palmitic acid is a long-chain saturated fatty acid that is found in many animal products, such as meat, butter, and cheese.
- B. Arachidic acid is a long-chain saturated fatty acid that occurs naturally in peanuts, peanut oil, and chocolate. It's one of the fatty acids that contributes to the solid, waxy texture of these foods.
- C. Stearic acid is a long-chain saturated fatty acid found in beef, lamb, and cocoa butter. It's one of the major solid fats present in these foods.
Q41. The conjugated molecule that is primarily present in egg albumin is
- A. Lipoprotein
- B. Nucleoprotein
- C. Glycolipid
- D. Glycoprotein✓
Explanation: Option D is correct.The conjugated molecule that is primarily present in egg albumin is glycoprotein. Egg albumin is a water-soluble protein that is found in the white of eggs. It is a major source of protein in the human diet and is also used in a variety of food products, such as mayonnaise, pasta, and baked goods. Egg albumin is a glycoprotein, which means that it is conjugated to carbohydrates. The carbohydrates are attached to the protein through glycosidic bonds. Glycosylation is a process that is important for the folding, stability, and function of many proteins. The other options are not conjugated molecules that are primarily present in egg albumin: Lipoproteins are conjugated molecules that are composed of proteins and lipids. They are found in the blood and transport lipids throughout the body.Nucleoproteins are conjugated molecules that are composed of proteins and nucleic acids. They are found in the nucleus of cells and play a role in gene expression. Glycolipids are conjugated molecules that are composed of carbohydrates and lipids. They are found in the cell membrane and play a role in cell communication and adhesion.
Why the other options are wrong
- A. Lipoproteins are conjugated molecules that are composed of proteins and lipids. They are found in the blood and transport lipids throughout the body.
- B. Nucleoproteins are conjugated molecules that are composed of proteins and nucleic acids. They are found in the nucleus of cells and play a role in gene expression.
- C. Glycolipids are conjugated molecules that are composed of carbohydrates and lipids. They are found in the cell membrane and play a role in cell communication and adhesion.
Q42. FSH (Follicle stimulating hormones) stimulates spermatogenesis by stimulating _ cells to complete the development of sperms
- A. Leydig
- B. Inhibin
- C. Sertoli✓
- D. TSH
Explanation: Option C is correct.FSH (Follicle stimulating hormones) stimulates spermatogenesis by stimulating Sertoli cells to complete the development of sperms. Sertoli cells are supporting cells that are found in the seminiferous tubules of the testes. They play a vital role in spermatogenesis, the process by which sperm cells are produced. FSH stimulates Sertoli cells to produce a number of factors that are essential for spermatogenesis, including: Androgen binding protein (ABP), which binds to testosterone and makes it available to developing sperm cells Growth factors, which promote the growth and development of sperm cells Inhibitin, which inhibits the production of FSH.Leydig cells are another type of cell that is found in the testes. They are responsible for producing testosterone, the male sex hormone. Testosterone is also essential for spermatogenesis, but it is produced in response to LH (luteinizing hormone), not FSH.Inhibin is a hormone that is produced by Sertoli cells. It inhibits the production of FSH and LH. This helps to ensure that the production of sperm cells is regulated.TSH (thyroid stimulating hormone) is a hormone that is produced by the pituitary gland. It stimulates the thyroid gland to produce thyroid hormones. Thyroid hormones are not involved in spermatogenesis.
Why the other options are wrong
- A. Leydig cells are another type of cell that is found in the testes. They are responsible for producing testosterone, the male sex hormone. Testosterone is also essential for spermatogenesis, but it is produced in response to LH (luteinizing hormone), not FSH.
- B. Inhibin is a hormone that is produced by Sertoli cells. It inhibits the production of FSH and LH. This helps to ensure that the production of sperm cells is regulated.
- D. TSH (thyroid stimulating hormone) is a hormone that is produced by the pituitary gland. It stimulates the thyroid gland to produce thyroid hormones. Thyroid hormones are not involved in spermatogenesis.
Q43. The process of photophosphorylation takes place in:
- A. Nucelolus
- B. Chloroplast✓
- C. Nucleus
- D. Golgi bodies
Explanation: Option B is correct.The process of photophosphorylation takes place in the chloroplast. Photophosphorylation is the process by which light energy is used to produce ATP, the energy currency of the cell. It is the light-dependent reaction of photosynthesis. Photophosphorylation takes place in the thylakoid membranes of the chloroplast. The thylakoid membranes are stacked sacs that contain chlorophyll, the light-absorbing pigment. When sunlight hits the chlorophyll, it excites the electrons in the chlorophyll molecules. These excited electrons are then passed through a series of electron carriers, which eventually leads to the production of ATP. The ATP that is produced by photophosphorylation is used to drive the Calvin cycle, the light-independent reaction of photosynthesis. The Calvin cycle uses ATP to convert carbon dioxide into sugar.The other options are not organelles where photophosphorylation takes place:The nucleolus is a small structure within the nucleus that is involved in the production of ribosomes.The nucleus is the control center of the cell and contains the cell's DNA.The Golgi apparatus is involved in the packaging and processing of proteins and lipid
Why the other options are wrong
- A. The nucleolus is a small structure within the nucleus that is involved in the production of ribosomes.
- C. The nucleus is the control center of the cell and contains the cell's DNA.
- D. The Golgi apparatus is involved in the packaging and processing of proteins and lipid
Q44. Which of the following hormones is released by the posterior lobe of the pituitary gland?
- A. Antidiuretic hormones✓
- B. Growth hormone
- C. Estrogen
- D. Prolactin
Explanation: Option A is correct. The posterior lobe of the pituitary gland releases antidiuretic hormone (ADH). ADH is also known as vasopressin. It is a hormone that helps the body retain water. ADH is released when the body's fluid levels are low. It acts on the kidneys to cause them to reabsorb more water from the urine. This helps to increase the body's fluid levels and prevent dehydration. The other options are not hormones that are released by the posterior lobe of the pituitary gland: Growth hormone is released by the anterior lobe of the pituitary gland. Estrogen is a female sex hormone that is produced by the ovaries and other tissues in the body. Prolactin is a hormone that is produced by the anterior lobe of the pituitary gland. It stimulates milk production in women.
Why the other options are wrong
- B. Growth hormone (GH), also known as somatotropin or human growth hormone (HGH), is a peptide hormone produced and secreted by the anterior pituitary gland that is essential for growth, cell reproduction, and regeneration.
- C. Estrogen is a female sex hormone that is produced by the ovaries and other tissues in the body, primarily known for its role in female sexual and reproductive development.
- D. Prolactin is a hormone that is produced by the anterior lobe of the pituitary gland. It stimulates milk production in women.
Q45. Which of the following agents can easily pass through filter paper?
- A. Bacteria
- B. Fungi
- C. Yeast
- D. Virus✓
Explanation: Viruses can easily pass through filter paper. Viruses are the smallest type of biological agent, with most being smaller than 0.1 micrometers in diameter. Filter paper typically has pores that are several micrometers in diameter, so viruses are small enough to pass through the pores. Viruses can easily pass through filter paper, while bacteria, fungi, and yeast cannot.Bacteria are single-celled organisms that are typically 0.5 to 5 micrometers in size. They are too large to pass through the pores of filter paper, which are typically 0.2 to 0.45 micrometers in diameter.Fungi are eukaryotic organisms that can be unicellular or multicellular. They typically range in size from a few micrometers to several meters. Fungi are too large to pass through the pores of filter paper.Yeast is a type of fungus that is unicellular and typically 5 to 10 micrometers in size. Yeast is too large to pass through the pores of filter paper.
Why the other options are wrong
- A. Bacteria are single-celled organisms that are typically 0.5 to 5 micrometers in size. They are too large to pass through the pores of filter paper, which are typically 0.2 to 0.45 micrometers in diameter.
- B. Fungi are eukaryotic organisms that can be unicellular or multicellular. They typically range in size from a few micrometers to several meters. Fungi are too large to pass through the pores of filter paper.
- C. Yeast is a type of fungus that is unicellular and typically 5 to 10 micrometers in size. Yeast is too large to pass through the pores of filter paper.
Q46. HIV belongs to a special class of virus known as:
- A. Retrovirus✓
- B. Flavivirus
- C. Novavirus
- D. Tetanus
Explanation: HIV belongs to a special class of virus known as retrovirus. Retroviruses are a type of virus that uses RNA as its genetic material. They are also unique in that they use an enzyme called reverse transcriptase to convert their RNA genome into DNA. This DNA is then integrated into the host cell's genome, where it can be transcribed and translated into viral proteins. Retroviruses are responsible for a number of diseases in humans and animals, including HIV/AIDS, leukemia, and lymphoma. HIV is a retrovirus that attacks the immune system, making it difficult for the body to fight off infection.
Why the other options are wrong
- B. Flaviviruses are a type of virus that is transmitted by mosquitoes and ticks. They are responsible for a number of diseases, including yellow fever, dengue fever, and Zika virus.
- C. Noroviruses are highly contagious viruses that commonly cause gastroenteritis. They spread easily and are a frequent cause of outbreaks involving vomiting and diarrhea.
- D. Tetanus is caused by a bacterium called Clostridium tetani. It is a serious disease that can cause muscle spasms and death.
Q47. The capsule of a bacterial cell is a sticky gelatinous structure made up of protein and:
- A. Lipids
- B. Carbohydrates✓
- C. Nucleotide
- D. Alcohol
Explanation: Option B is correct.The capsule of a bacterial cell is a sticky gelatinous structure made up of carbohydrates. The capsule is a layer of polysaccharide material that surrounds the cell wall of some bacteria. It is composed of repeating units of sugar molecules. The capsule is a dynamic structure that can be produced or shed by the bacteria in response to environmental conditions. The capsule has a number of functions, including: Protecting the bacteria from dehydration Helping the bacteria to adhere to surfaces Evasion of the host immune system Some bacteria, such as Streptococcus pneumoniae, have a thick capsule that is essential for their virulence. The capsule protects the bacteria from phagocytosis, a process by which white blood cells engulf and destroy bacteria. The other options are not components of the bacterial capsule: Lipids are a type of organic molecule that is made up of fatty acids and glycerol. They are found in the cell membrane and other cellular structures. Nucleotides are the building blocks of DNA and RNA. Nucleotides are joined together by phosphodiester bonds to form DNA and RNA molecules. The order of the nucleotides in DNA and RNA determines the genetic code. Alcohols are a type of organic molecule that contains a hydroxyl group (OH). They are found in a variety of foods and beverages.
Why the other options are wrong
- A. Lipids are a type of organic molecule that is made up of fatty acids and glycerol. They are found in the cell membrane and other cellular structures.
- C. Nucleotides are the building blocks of DNA and RNA. Nucleotides are joined together by phosphodiester bonds to form DNA and RNA molecules. The order of the nucleotides in DNA and RNA determines the genetic code.
- D. Alcohols are a type of organic molecule that contains a hydroxyl group (OH). They are found in a variety of foods and beverages.
Q48. The transgenic plants, such as golden rice, are produced primarily with the help of:
- A. Escherichia coli
- B. Proteus mirabilis
- C. Agrobacterium tumerfaciens✓
- D. Ralstonia solanacearum
Explanation: Transgenic plants such as golden rice are produced primarily with the help of Agrobacterium tumefaciens. Agrobacterium tumefaciens is a bacterium that causes crown gall disease in plants. It is also a natural genetic engineer, as it can transfer its own DNA into plant cells. This ability has been exploited to create transgenic plants, which are plants that have had their DNA modified to include genes from other organisms.
Why the other options are wrong
- A. Escherichia coli is a bacterium that is commonly used in molecular biology research. It is not a natural genetic engineer and cannot transfer its DNA into plant cells.
- B. Proteus mirabilis is a bacterium that causes urinary tract infections. It is not a natural genetic engineer and cannot transfer its DNA into plant cells.
- D. Ralstonia solanacearum is a bacterium that causes bacterial wilt in plants. It is not a natural genetic engineer and cannot transfer its DNA into plant cells.
Q49. Which of the following chemicals is most commonly used to preserve biological specimen?
- A. Formalin✓
- B. Glutaraldehyde
- C. Ethylene Oxide
- D. Iodine
Explanation: Formalin is a solution of formaldehyde in water. It is the most common preservative used for biological specimens, as it is effective and inexpensive. Formalin preserves specimens by cross-linking proteins, which prevents them from decaying.
Why the other options are wrong
- B. Glutaraldehyde is another aldehyde that is used to preserve biological specimens. It is more expensive than formalin, but it is also more effective at preserving fine details. Glutaraldehyde is often used to preserve specimens for electron microscopy.
- C. Ethylene oxide is a gas that is used to sterilize and preserve biological specimens. It is effective at killing all microorganisms, including bacteria, viruses, and fungi. Ethylene oxide is often used to preserve specimens for museums and other collections.
- D. Iodine is a halogen that is used to preserve biological specimens. It is not as effective as the other chemicals on your list, but it is less toxic and can be used to preserve specimens that are intended for human consumption. Iodine is often used to preserve seafood and other foods.
Q50. Coral reef are the characteristic feature of phylum:
- A. Porifera
- B. Coelenterata/Cnidaria✓
- C. Arthropoda
- D. Platyhelminthes
Explanation: Coral reefs are the characteristic feature of the phylum Cnidaria. Cnidaria is a phylum of aquatic invertebrates that includes corals, sea anemones, jellyfish, and hydras. Cnidarians are characterized by their radial symmetry, the presence of nematocysts (stinging cells), and a gastrovascular cavity (a single opening that serves as both a mouth and an anus). Coral reefs are built by colonial cnidarians called scleractinian corals. Scleractinian corals secrete a hard calcium carbonate skeleton that supports the reef structure. Coral reefs are found in warm, shallow waters around the world and are home to a wide variety of marine life.
Why the other options are wrong
- A. Porifera is the phylum of sponges. Sponges are filter feeders that live in marine and freshwater habitats.
- C. Arthropoda is the phylum of insects, spiders, crustaceans, and other invertebrates. Arthropods are characterized by their segmented bodies and jointed appendages.
- D. Platyhelminthes is the phylum of flatworms. Flatworms are parasitic or free-living invertebrates that have a flattened body plan.
Q51. According to the sliding filament hypothesis, the release of_ from the sarcoplasmic reticulum causes the reorientation of certain components in the thin filament, permitting them to bind with extension from the thick myosin filaments:
- A. Sodium
- B. Calcium✓
- C. Magnesium
- D. Potassium
Explanation: Option B is correct. According to the sliding filament hypothesis, the release of calcium ions from the sarcoplasmic reticulum causes the reorientation of certain components in the thin filament, permitting them to bind with extension from the thick myosin filaments. Calcium ions play a crucial role in muscle contraction by binding to the protein troponin on the thin filament. This binding causes tropomyosin to move out of the way, exposing myosin binding sites on the actin filament. Myosin heads can then bind to these sites, and cross-bridges can be formed. The cross-bridges then power the sliding of the thin filaments past the thick filaments, which results in muscle contraction. The other options are not involved in muscle contraction: Sodium ions are involved in nerve conduction and muscle action potentials. Magnesium ions are cofactors for many enzymes, including those involved in muscle metabolism. Potassium ions are involved in maintaining the resting membrane potential of muscle cells.
Why the other options are wrong
- A. Sodium ions are involved in nerve conduction and muscle action potentials.
- C. Magnesium ions are cofactors for many enzymes, including those involved in muscle metabolism.
- D. Potassium ions are involved in maintaining the resting membrane potential of muscle cells.
Q52. The green glands found in arthropods are concerned with:
- A. Excretion✓
- B. Respiration
- C. Digestion
- D. Circulation
Explanation: Option A is correct.The green glands found in arthropods are concerned with excretion. Green glands are paired excretory organs that are found in the head of crustaceans. They are responsible for filtering waste products from the blood and excreting them from the body. Green glands are also thought to play a role in osmoregulation, the process of maintaining a balance of water and salts in the body. The other options are not functions of the green glands:Respiration is the process of exchanging oxygen and carbon dioxide between the body and the environment. Arthropods respire through a variety of structures, including gills, tracheae, and book lungs. Digestion is the process of breaking down food into smaller molecules that can be absorbed by the body. Arthropods digest food in a variety of ways, including through their mouths, stomachs, and intestines.Circulation is the movement of blood throughout the body. Arthropods have an open circulatory system, in which the blood does not flow in closed vessels.
Why the other options are wrong
- B. Respiration is the process of exchanging oxygen and carbon dioxide between the body and the environment. Arthropods respire through a variety of structures, including gills, tracheae, and book lungs.
- C. Digestion is the process of breaking down food into smaller molecules that can be absorbed by the body. Arthropods digest food in a variety of ways, including through their mouths, stomachs, and intestines.
- D. Circulation is the movement of blood throughout the body. Arthropods have an open circulatory system, in which the blood does not flow in closed vessels.
Q53. The Purkinje fibers are the specialized fibers found in:
- A. Human heart✓
- B. Human lungs
- C. Human stomach
- D. Human brain
Explanation: Option A is correct.The Purkinje fibers are the specialized fibers found in the human heart. Purkinje fibers are a network of specialized cardiac muscle fibers that conduct electrical impulses from the atrioventricular node (AV node) to the ventricles of the heart. They are responsible for coordinating the contraction of the ventricles, which allows them to pump blood efficiently. The Purkinje fibers are located in the subendocardial layer of the heart, which is the layer of muscle tissue that is closest to the endocardium, the inner lining of the heart. They are large, pale fibers that are easily distinguished from the surrounding cardiac muscle cells. The other options are not organs where Purkinje fibers are found: Lungs are the organs of respiration. They are responsible for exchanging oxygen and carbon dioxide between the body and the environment. The stomach is a digestive organ that is responsible for breaking down food into smaller molecules that can be absorbed by the body. The brain is the central nervous system organ that is responsible for controlling all of the body's functions.
Why the other options are wrong
- B. Lungs are the organs of respiration. They are responsible for exchanging oxygen and carbon dioxide between the body and the environment.
- C. The stomach is a digestive organ that is responsible for breaking down food into smaller molecules that can be absorbed by the body.
- D. The brain is the central nervous system organ that is responsible for controlling all of the body's functions.
Q54. The largest body of lymphoid tissue in the human body is:
- A. Tonsils
- B. Pancreas
- C. Spleen✓
- D. Thymus
Explanation: Option C is correct.The largest body of lymphoid tissue in the human body is the spleen. The spleen is a soft, purplish organ located in the upper left abdomen, beneath the diaphragm and posterior to the stomach. It is about 5 inches long and 2 inches wide. The spleen is a major part of the lymphatic system, which is responsible for fighting infection and disease. The spleen contains two types of tissue: white pulp and red pulp. The white pulp contains lymphocytes, which are white blood cells that play a key role in the immune system. The red pulp contains macrophages, which are scavenger cells that engulf and destroy bacteria and other foreign invaders. The spleen has a number of important functions, including: Filtering blood to remove bacteria, dead cells, and other debris Producing and storing lymphocytes Regulating the production of red blood cells Helping to fight infection and diseaseThe other options are not the largest body of lymphoid tissue in the human body: Tonsils are small, round masses of lymphoid tissue located at the back of the throat. They help to protect the body from infection by trapping bacteria and viruses.The pancreas is a digestive organ that produces enzymes that help to break down food. It also produces hormones, such as insulin and glucagon, which regulate blood sugar levels. The thymus is a lymphoid organ located in the chest, behind the breastbone. It is responsible for the maturation of T lymphocytes, a type of white blood cell that plays a key role in the cell-mediated immune response.
Why the other options are wrong
- A. Tonsils are small, round masses of lymphoid tissue located at the back of the throat. They help to protect the body from infection by trapping bacteria and viruses.
- B. The pancreas is a digestive organ that produces enzymes that help to break down food. It also produces hormones, such as insulin and glucagon, which regulate blood sugar levels.
- D. The thymus is a lymphoid organ located in the chest, behind the breastbone. It is responsible for the maturation of T lymphocytes, a type of white blood cell that plays a key role in the cell-mediated immune response.
Q55. The immune cells that clean up pus as a part of the healing process is:
- A. Natural killer cell
- B. Macrophages✓
- C. Antibodies
- D. Neutrophils
Explanation: Neutrophils are the first responders — they rush to the infection site, attack bacteria, and die in large numbers.During healing, macrophages arrive after neutrophils and clean up the dead cells, bacteria, and debris — including pus (which is mostly dead neutrophils and tissue).They “eat up” the waste through phagocytosis, helping tissues heal properlyAntibodies are proteins that are produced by B lymphocytes in response to infection. They bind to specific antigens on the surface of pathogens, which helps to neutralize them and mark them for destruction by other immune cells.
Why the other options are wrong
- A. Natural killer cells are a type of white blood cell that is involved in the innate immune response. They are able to kill infected cells and tumor cells without the need for prior sensitization.
- C. Antibodies are proteins that are produced by B lymphocytes in response to infection. They bind to specific antigens on the surface of pathogens, which helps to neutralize them and mark them for destruction by other immune cells
- D. Neutrophils are the first responders — they rush to the infection site, attack bacteria, and die in large numbers.
Q56. Lipid synthesis occurs in which one of the following cell organelles?
- A. Ribosomes
- B. Golgi bodies
- C. Mitochondria
- D. Endoplasmic reticulum✓
Explanation: Option D is correct.Lipid synthesis occurs in the endoplasmic reticulum (ER) of the cell. The ER is a network of interconnected tubules and sacs that is found in the cytoplasm of all eukaryotic cells. It is involved in a variety of cellular functions, including protein synthesis, lipid synthesis, and detoxification. Lipid synthesis occurs on the smooth ER, which is a type of ER that does not have ribosomes. The smooth ER contains a number of enzymes that are involved in the synthesis of different types of lipids, including triglycerides, phospholipids, and cholesterol. Once lipids have been synthesized in the ER, they are transported to other parts of the cell, such as the Golgi apparatus and the plasma membrane. Lipids are also used to build cell membranes and other cellular organelles. The other options are not organelles where lipid synthesis occurs: Ribosomes are organelles that are responsible for protein synthesis. Golgi bodies are organelles that are involved in the processing and packaging of proteins. Mitochondria are organelles that are responsible for energy production.
Why the other options are wrong
- A. Ribosomes are the cell’s protein-making organelles. They read the mRNA code and assemble amino acids in the correct order to build proteins.
- B. Golgi bodies are organelles that handle the processing, sorting, and packaging of proteins before they are sent to their final destinations in the cell or outside it.
- C. Mitochondria are organelles that generate most of the cell’s energy. They produce ATP through cellular respiration, making them the cell’s main power source.
Q57. The testes are male gonads which are situated outside the abdomen within a skin pouch called :
- A. Vas deferens
- B. Epididymis
- C. Scrotum✓
- D. Vasa efferentia
Explanation: Option C is correct.The testes are male gonads which are situated outside the abdomen within a skin pouch called scrotum. The scrotum is a pouch of skin that hangs below the penis. It contains the testes, epididymis, and part of the vas deferens.The epididymis is a long, coiled tube that lies along the back of each testis. It stores and matures sperm.The vas deferens is a tube that carries sperm from the epididymis to the ejaculatory duct.The vasa efferentia are a series of thin tubes that carry sperm from the testes to the epididymis.
Why the other options are wrong
- A. The vas deferens is a tube that carries sperm from the epididymis to the ejaculatory duct.
- B. The epididymis is a long, coiled tube that lies along the back of each testis. It stores and matures sperm.
- D. The vasa efferentia are a series of thin tubes that carry sperm from the testes to the epididymis.
Q58. The term polydipsia refers to:
- A. A condition in which abnormally large volume of urine is produced
- B. A condition of exessive thirst✓
- C. A condition of excessive hunger
- D. A condition in which the concentration of blood decreases in the body
Explanation: Option B is correct.The term polydipsia refers to a condition of excessive thirst. It is a symptom of many medical conditions, including diabetes, diabetes insipidus, psychogenic polydipsia, and certain medications. Polydipsia can also be caused by dehydration, hot weather, and strenuous exercise. When a person has polydipsia, they may drink more than three liters of fluids per day. This can lead to frequent urination, which can be disruptive to daily life. If you are experiencing polydipsia, it is important to see a doctor to determine the underlying cause and get the appropriate treatment.The other options are not the definition of polydipsia: Polyuria is a condition in which a person produces abnormally large amounts of urine. Polyphagia is a condition of excessive hunger. Hypovolemia is a condition in which the concentration of blood decreases in the body.
Why the other options are wrong
- A. Polyuria is a condition in which a person produces abnormally large amounts of urine.
- C. Polyphagia is a condition of excessive hunger.
- D. Hypovolemia is a condition in which the concentration of blood decreases in the body.
Q59. Lactose is composed of:
- A. Glucose + Fructose
- B. Glucose + Galactose✓
- C. Glucose + Glucose
- D. Fructose + Galactose
Explanation: Option B is correct.Lactose is composed of glucose + galactose. Lactose is a disaccharide, which means that it is made up of two monosaccharides (simple sugars). The two monosaccharides that make up lactose are glucose and galactose. Lactose is found in milk and other dairy products. It is also used in a variety of food products, such as bread, candy, and ice cream. Lactose is broken down into glucose and galactose in the small intestine by the enzyme lactase. Glucose and galactose are then absorbed into the bloodstream and used by the body for energy. People who are lactose intolerant are unable to digest lactose properly. This is because they lack the enzyme lactase.
Why the other options are wrong
- A. Lactose is a disaccharide formed by linking one glucose molecule with one galactose molecule. These two sugars are joined by a β-1,4 glycosidic bond. This combination is what gives lactose its characteristic properties and makes it the main sugar found in milk.
- C. Lactose is made up of two simple sugars—glucose and galactose—joined together by a β-1,4 bond. This pairing forms the milk sugar found in dairy products.
- D. Lactose is a disaccharide formed by linking one glucose molecule with one galactose molecule. These two sugars are joined by a β-1,4 glycosidic bond. This combination is what gives lactose its characteristic properties and makes it the main sugar found in milk.
Q60. Saprophytic bacteria are:
- A. Autotrophs
- B. Decomposers✓
- C. Parasites
- D. Photosynthetic
Explanation: Option B is correct.Saprophytic bacteria are decomposers. Decomposers are organisms that break down dead organic matter. Saprophytic bacteria play an important role in the environment by breaking down dead plants and animals, which releases nutrients back into the soil and air. Examples of saprophytic bacteria include: Bacillus subtilis, Clostridium tetani ,Escherichia coliAutotrophs are organisms that can make their own food from sunlight and carbon dioxide. Decomposers are not autotrophs because they cannot make their own food. Parasites are organisms that live on or inside another organism and get their nutrients from that organism. Saprophytic bacteria are not parasites because they do not live on or inside another organism. Photosynthetic organisms are organisms that use sunlight to convert carbon dioxide into oxygen and carbohydrates. Saprophytic bacteria are not photosynthetic because they do not use sunlight to make their own food.
Why the other options are wrong
- A. Autotrophs are organisms that can make their own food from sunlight and carbon dioxide. Decomposers are not autotrophs because they cannot make their own food.
- C. Parasites are organisms that live on or inside another organism and get their nutrients from that organism. Saprophytic bacteria are not parasites because they do not live on or inside another organism.
- D. Photosynthetic organisms are organisms that use sunlight to convert carbon dioxide into oxygen and carbohydrates. Saprophytic bacteria are not photosynthetic because they do not use sunlight to make their own food.
Q61. In human heart's right atrium communicates with the right ventricle through:
- A. Inter-auricular septum
- B. Ventricular septum
- C. Tricuspid valve✓
- D. Bicuspid valve
Explanation: Option C is correct.In the human heart, the right atrium communicates with the right ventricle through the tricuspid valve. The tricuspid valve is a one-way valve that prevents blood from flowing back from the right ventricle to the right atrium. It is made up of three thin cusps (flaps) that are attached to chordae tendineae (tendinous cords). The chordae tendineae are attached to the papillary muscles, which are small muscles located on the inner walls of the right ventricle. When the right atrium contracts, it forces blood through the open tricuspid valve into the right ventricle. When the right ventricle contracts, it closes the tricuspid valve to prevent blood from flowing back into the right atrium. The other options are not structures that connect the right atrium to the right ventricle: The interatrial septum is a wall that separates the right atrium from the left atrium. The ventricular septum is a wall that separates the right ventricle from the left ventricle. The bicuspid valve, also known as the mitral valve, is a valve that connects the left atrium to the left ventricle.
Why the other options are wrong
- A. The interatrial septum is a wall that separates the right atrium from the left atrium.
- B. The ventricular septum is a wall that separates the right ventricle from the left ventricle.
- D. The bicuspid valve, also known as the mitral valve, is a valve that connects the left atrium to the left ventricle.
Q62. The first segment of the small intestine is:
- A. Duodenum✓
- B. Jejunum
- C. Ileum
- D. Colon
Explanation: Option A is correct. The first segment of the small intestine is the duodenum. The small intestine is a long, coiled tube that is divided into three parts: the duodenum, the jejunum, and the ileum. The duodenum is the shortest and widest part of the small intestine. It is about 10 inches long and curves around the head of the pancreas. The duodenum is responsible for the initial digestion of food. It receives food from the stomach and mixes it with digestive juices from the pancreas and liver. The digestive juices in the duodenum break down carbohydrates, proteins, and fats into smaller molecules that can be absorbed into the bloodstream. The other options are not the first segment of the small intestine: The jejunum is the second segment of the small intestine. It is about 16 feet long and is located between the duodenum and the ileum. The jejunum is responsible for the absorption of most of the nutrients from food. The ileum is the third and longest segment of the small intestine. It is about 20 feet long and is located between the jejunum and the colon. The ileum is responsible for the absorption of the remaining nutrients from food, as well as the absorption of bile salts and water. The colon is the large intestine. It is about 5 feet long and is located between the ileum and the rectum. The colon is responsible for the absorption of water and the storage of waste products.
Why the other options are wrong
- B. The jejunum is the second segment of the small intestine. It is about 16 feet long and is located between the duodenum and the ileum. The jejunum is responsible for the absorption of most of the nutrients from food.
- C. The ileum is the third and longest segment of the small intestine. It is about 20 feet long and is located between the jejunum and the colon. The ileum is responsible for the absorption of the remaining nutrients from food, as well as the absorption of bile salts and water.
- D. The colon is the large intestine. It is about 5 feet long and is located between the ileum and the rectum. The colon is responsible for the absorption of water and the storage of waste products.
Q63. Which one of the following factors does not affect the rate of enzyme action?
- A. Enzyme concentration
- B. Substrate concentration
- C. Light intensity✓
- D. Temperature
Explanation: Light intensity does not directly affect enzyme activity because enzymes are not influenced by light. They are affected by factors like temperature, pH and concentrations of enzyme and substrate.
Why the other options are wrong
- A. Enzyme concentration affects the rate of reaction because more enzymes can catalyze more substrate molecules, increasing the reaction rate up to a certain point.
- B. Substrate concentration influences the rate of enzyme action; higher substrate levels can lead to an increased rate of reaction until the enzymes become saturated.
- D. Temperature affects enzyme activity; each enzyme has an optimal temperature range for maximum activity, and extreme temperatures can denature enzymes.
Q64. Light reaction occurs in the _ of chloroplast:
- A. Outer membrane
- B. Inner membrane
- C. Granum✓
- D. Stroma
Explanation: Option C is correct.The light reaction occurs in the grana of the chloroplast. The chloroplast is a specialized organelle in plant cells that is responsible for photosynthesis. Photosynthesis is the process by which plants use sunlight, water, and carbon dioxide to produce oxygen and sugar. The chloroplast is divided into two parts: the stroma and the thylakoids. The stroma is a gel-like fluid that contains the enzymes needed for the Calvin cycle, the second stage of photosynthesis. The thylakoids are a series of flattened sacs that are stacked together to form grana. The light reaction occurs in the thylakoids of the chloroplast. The thylakoids contain chlorophyll, a green pigment that absorbs sunlight. The sunlight energy is used to split water molecules into hydrogen and oxygen. The hydrogen atoms are used to produce NADPH, a molecule that stores energy. The oxygen atoms are released into the atmosphere. The products of the light reaction, NADPH and ATP, are used in the Calvin cycle to produce sugar. The other options are not parts of the chloroplast where the light reaction occurs: The outer membrane is a thin membrane that surrounds the chloroplast. It protects the chloroplast from the outside environment. The inner membrane is a thicker membrane that surrounds the stroma. It controls the movement of molecules into and out of the chloroplast. The stroma is the gel-like fluid that contains the enzymes needed for the Calvin cycle.
Why the other options are wrong
- A. The outer membrane is a thin membrane that surrounds the chloroplast. It protects the chloroplast from the outside environment.
- B. The inner membrane is a thicker membrane that surrounds the stroma. It controls the movement of molecules into and out of the chloroplast.
- D. The stroma is the gel-like fluid that contains the enzymes needed for the Calvin cycle.
Q65. How many pieces of ribonucleic acid (RNA) make up the genome of influenza virus?
- A. 4
- B. 6
- C. 8✓
- D. 10
Explanation: The influenza virus genome is composed of eight pieces of ribonucleic acid (RNA). This virus is classified as a segmented RNA virus, which means its genetic material is divided into multiple RNA segments. Each of the eight segments encodes one or more proteins that are crucial for the virus's ability to replicate and cause infection. The segmentation of the genome allows the virus to undergo reassortment, which is a process that contributes to its genetic diversity and ability to evade the immune system, leading to new strains and potential pandemics. The other options (A, B, and D) are incorrect as they misrepresent the number of RNA segments in the influenza virus genome.
Why the other options are wrong
- A. This option is incorrect. The influenza virus does not have a genome made up of four segments; it has more segments that allow for complex genetic information storage.
- B. This option is incorrect as well. Although some viruses may have six segments, the influenza virus specifically has eight segments in its RNA genome.
- D. This option is incorrect. The influenza virus does not have a genome with ten segments; it is specifically known to have eight segments.
Q66. In Mendelian cross for the heterozygous flower, what is the probability that the dominant allele will be in sperm and the recessive in the egg:
- A. 0.05
- B. 0.5
- C. 0.25✓
- D. 0.7
Explanation: In a Mendelian cross involving a heterozygous flower (say, Rr, where:R = dominant allele (e.g., red color)r = recessive allele (e.g., white color)We want the probability that:The sperm carries the dominant allele (R)The egg carries the recessive allele (r)Step-by-step Explanation:In a heterozygous (Rr) individual:Probability of sperm carrying R = ½Probability of egg carrying r = ½Since the sperm and egg assort independently (law of independent assortment), we multiply the probabilities:P(sperm = R and egg = r) = ½ × ½ = ¼
Why the other options are wrong
- A. This value is far too low.In a simple Mendelian monohybrid cross, gamete probabilities are never that small — they’re fractions like ½, ¼, etc.Thus, incorrect.
- B. This would only be true if either sperm or egg were being considered individually — not both together.Since both must occur simultaneously (R in sperm and r in egg), we must multiply the probabilities (½ × ½ = ¼).Hence, 0.5 is incorrect.
- D. This has no genetic basis in Mendelian probability.It’s too large and inconsistent with the 1:1 segregation ratio of alleles.Hence, incorrect.
Q67. Mastication causes exocrine glands under the tongue and in the back of the mouth to secrete a watery liquid called:
- A. Bolus
- B. Bile
- C. Pancreatic juice
- D. Saliva✓
Explanation: Option D is correct. Mastication causes exocrine glands under the tongue and in the back of the mouth to secrete a watery liquid called saliva. Saliva is a complex fluid that contains water, enzymes, and other molecules. It plays a number of important roles in digestion. Saliva is secreted by three pairs of major salivary glands: the parotid glands, the submandibular glands, and the sublingual glands. These glands are located in the head and neck, and they release saliva into the mouth through ducts. When you chew food, the salivary glands are stimulated to produce more saliva. This helps to moisten the food and break it down into smaller pieces. The saliva also contains enzymes that start to break down carbohydrates, such as starch, into smaller molecules that can be absorbed by the body. Saliva is an essential part of digestion, and it helps to keep the mouth healthy. Without saliva, it would be difficult to swallow food, and digestion would be less efficient. The other options are not liquids secreted by exocrine glands in the mouth: a Bolus is a mixture of chewed food and saliva that is formed in the mouth. Bile is a digestive fluid that is produced by the liver and stored in the gallbladder. It is released into the small intestine to help digest fats. Pancreatic juice is a digestive fluid that is produced by the pancreas. It is released into the small intestine to help digest carbohydrates, proteins, and fats.
Why the other options are wrong
- A. In the process of digestion, a bolus is a soft, round mass of chewed food that has been mixed with saliva and is ready to be swallowed.
- B. Bile is a digestive fluid that is produced by the liver and stored in the gallbladder. It is released into the small intestine to help digest fats.
- C. Pancreatic juice is a digestive fluid that is produced by the pancreas. It is released into the small intestine to help digest carbohydrates, proteins, and fats.
Q68. In phylum Aschelminths (Nematoda) nervous system consists of a nerve ring which encircles the _ and sends its branches in different parts of the body
- A. Lips
- B. Teeth
- C. Stomach
- D. Pharynx✓
Explanation: Option D is correct.In phylum Aschelminths (Nematoda), the nervous system consists of a nerve ring which encircles the pharynx. The pharynx is a muscular tube that is located at the anterior (front) end of the nematode body. It is responsible for sucking in food and moving it to the digestive system. The nerve ring is a cluster of ganglia (nerve cell bodies) that encircles the pharynx. The nerve ring serves as a central nervous system for the nematode, and it sends nerve branches to all parts of the body. The other options are not parts of the nematode body that are encircled by the nerve ring: Lips are not present in nematodes.Teeth are not present in nematodes.The stomach is located in the posterior (back) end of the nematode body.
Why the other options are wrong
- A. Lips are not present in nematodes.
- B. Teeth are not present in nematodes.
- C. The stomach is located in the posterior (back) end of the nematode body.
Q69. Salmonella typhi causing typhoid and Clostridium tetani causing tetanus are which type of bacteria?
- A. Bacilli✓
- B. Spirilla
- C. Cocci
- D. Comma
Explanation: Option A is correct.Salmonella typhi and Clostridium tetani are both bacilli. Bacilli are rod-shaped bacteria. They are one of the three main shapes of bacteria, along with cocci (spherical bacteria) and spirilla (spiral bacteria). Bacilli are found in a wide variety of environments, including soil, water, and the human body. Some bacilli are beneficial, such as those that produce lactic acid in yogurt and cheese. Other bacilli are pathogens, which means that they can cause disease. Salmonella typhi and Clostridium tetani are both examples of pathogenic bacilli. Salmonella typhi causes typhoid, a serious disease that can be fatal if it is not treated. Typhoid is transmitted through contaminated food and water. It causes fever, headache, and diarrhea. Clostridium tetani causes tetanus, a disease that affects the nervous system. Tetanus is caused by a toxin that is produced by the bacteria. The toxin causes muscle spasms, which can be severe and life-threatening. Tetanus is transmitted through contact with contaminated soil or other objects. Both Salmonella typhi and Clostridium tetani can be prevented by vaccination. The typhoid vaccine is recommended for people who are traveling to areas where typhoid is common. The tetanus vaccine is recommended for everyone as part of the routine childhood immunization schedule.Spirilla:Spiral bacteria.Example; Campylobacter (food poisoning), Leptospira (leptospirosis), Treponema pallidum (syphilis) Cocci: Spherical bacteria.Examples; Streptococcus (strep throat), Staphylococcus (staph infection), Neisseria (meningitis, gonorrhea) Comma-shaped bacteria are a type of spirilla. Comma-shaped bacteria include: Vibrio cholerae (cholera), Vibrio parahaemolyticus (food poisoning), and Helicobacter pylori (stomach ulcers).
Why the other options are wrong
- B. Spirilla:Spiral bacteria.Example; Campylobacter (food poisoning), Leptospira (leptospirosis), Treponema pallidum (syphilis)
- C. Cocci: Spherical bacteria.Examples; Streptococcus (strep throat), Staphylococcus (staph infection), Neisseria (meningitis, gonorrhea)
- D. Comma-shaped bacteria are a type of spirilla. Comma-shaped bacteria include: Vibrio cholerae (cholera), Vibrio parahaemolyticus (food poisoning), and Helicobacter pylori (stomach ulcers).
Q70. Who formulated the principle that "ontogeny recapitulates phylogeny"?
- A. Von bear
- B. Hackel✓
- C. Herbert Spencer
- D. Darwin
Explanation: Option B is correct.The principle that "ontogeny recapitulates phylogeny" was formulated by Ernst Hackel. Hackel was a German biologist who lived from 1834 to 1919. He was a major proponent of Darwin's theory of evolution, and he made a number of important contributions to the field of biology. The principle of ontogeny recapitulating phylogeny states that the development of an individual organism (ontogeny) mirrors the evolutionary history of its species (phylogeny). In other words, as an embryo develops, it goes through stages that resemble the adult forms of its evolutionary ancestors. Hackel based his theory on observations of the development of various animals, including humans. He noted that at certain stages of development, human embryos have features that are similar to those of fish, reptiles, and other animals. The other options are not scientists who formulated the principle of ontogeny recapitulating phylogeny: Karl Ernst von Baer was a German biologist who lived from 1792 to 1876. He is known for his work on the development of embryos. Herbert Spencer was an English philosopher and sociologist who lived from 1820 to 1903. He is known for his work on social Darwinism. Charles Darwin was an English naturalist who lived from 1809 to 1882. He is known for his theory of evolution by natural selection.
Why the other options are wrong
- A. Karl Ernst von Baer was a German biologist (1792–1876) who made foundational contributions to embryology, including the discovery of the mammalian ovum and formulating principles of embryonic development that showed general features appear before specialized ones.
- C. Herbert Spencer was an English philosopher and sociologist (1820–1903) who applied the concept of "survival of the fittest" to societies, developing the theory of social Darwinism, which compared societal evolution to biological evolution.
- D. Charles Darwin was an English naturalist (1809–1882) who formulated the theory of evolution by natural selection, explaining how species adapt and evolve over time through differential survival and reproduction.
Q71. Aquatic mammals belong to the order _
- A. Cetacea✓
- B. Pholidote
- C. Chiroptera
- D. Proboscidea
Explanation: Option A is correct.Aquatic mammals belong to the order Cetacea. Cetaceans are a group of marine mammals that includes whales, dolphins, and porpoises. They are characterized by their streamlined bodies, flippers, and lack of hind limbs. Cetaceans are also known for their intelligence and complex social behavior. The other options are orders of mammals that are not aquatic: Pholidota is the order of mammals that includes pangolins. Pangolins are scaly mammals that are found in Africa and Asia. Chiroptera is the order of mammals that includes bats. Bats are the only mammals that can fly. Proboscidea is the order of mammals that includes elephants. Elephants are the largest land mammals on Earth.
Why the other options are wrong
- B. Pholidota is the order of mammals that includes pangolins. Pangolins are scaly mammals that are found in Africa and Asia.
- C. Chiroptera is the order of mammals that includes bats. Bats are the only mammals that can fly.
- D. Proboscidea is the order of mammals that includes elephants. Elephants are the largest land mammals on Earth.
Q72. All of the following paired organs/structures have homology except:
- A. Human hand: Bat's wing
- B. Bat's wing: Wings of butterfly✓
- C. Horse front leg: Front flappers of Whale
- D. Forelimb of a cat: Forelimb of a whale.
Explanation: The wings of a bat and the wings of a butterfly are analogous structures, but not homologous. Analogous structures are structures that have similar functions but different evolutionary origins. Homologous structures are structures that have similar evolutionary origins but may have different functions. The wings of a bat and the wings of a butterfly are both used for flight, but they have evolved independently from each other. The wings of a bat are modified forelimbs, while the wings of a butterfly are modified outgrowths of the thorax.
Why the other options are wrong
- A. A human hand and a bat’s wing share the same basic bone pattern, so they are homologous structures. Both came from a common vertebrate ancestor. They look different now because each adapted to a different function.
- C. The horse’s front leg and the whale’s front flippers are homologous structures. They have the same underlying bone pattern because they came from a common ancestral limb, even though they now serve very different functions.
- D. They are homologous. They look different and serve different purposes, but the bone layout is the same, showing a shared ancestry.
Q73. The head of some phages are icosahedral, which means that the head possesses:
- A. 6 Sides
- B. 10 Sides
- C. 15 Sides
- D. 20 Sides✓
Explanation: The head of some phages are icosahedral, which means that the head possesses 20 sides. An icosahedron is a polyhedron defined by having 20 equilateral triangular faces. It is one of the five Platonic solids, recognized for its symmetry and structural efficiency. The icosahedral shape allows for optimal packing of viral proteins and DNA, contributing to the stability and resilience of the virus against environmental stressors. Examples of phages with icosahedral heads include T4 phage, T7 phage, Lambda phage, and MS2 phage. The other options are incorrect because they do not represent the true structural nature of an icosahedron, which is specifically characterized by its 20 triangular faces.
Why the other options are wrong
- A. This option is incorrect. An icosahedron has more than 6 sides; it is a polyhedron with many more faces.
- B. This option is incorrect. An icosahedron does not have 10 sides; it is defined by having 20 triangular faces.
- C. This option is incorrect. An icosahedron cannot have 15 sides; the correct number of sides is 20.
Q74. In sickle cell, haemoglobin molecule, glutamic acid, is replaced by:
- A. Proline
- B. Glutamine
- C. Valine✓
- D. Glycine
Explanation: Option C is correct. In sickle cell anemia, glutamic acid in the hemoglobin molecule is replaced by valine. This single amino acid substitution leads to the hemoglobin molecules becoming sticky and clumping together when oxygen levels are low. This causes the formation of sickle-shaped red blood cells, which can obstruct blood vessels and lead to severe complications such as pain, stroke, and other health issues. Sickle cell anemia is a genetic condition resulting from a mutation in the hemoglobin gene and is especially prevalent among individuals of African descent. The other options (Proline, Glutamine, Glycine) do not correctly identify the amino acid involved in this specific mutation, and therefore, do not explain the pathology of sickle cell anemia.
Why the other options are wrong
- A. Proline is an amino acid, but it does not replace glutamic acid in sickle cell anemia. The introduction of proline would not lead to the characteristic sickling of red blood cells.
- B. Glutamine is similar to glutamic acid but differs in structure. It does not replace glutamic acid in sickle cell anemia, and its presence would not cause the hemoglobin to behave abnormally.
- D. Glycine is another amino acid that does not replace glutamic acid in sickle cell anemia. Its introduction would not cause the specific pathology associated with this condition.
Q75. Where do phospholipids arrange themselves in a cell?
- A. Inside the nucleus
- B. Inside the cytoplasm
- C. Inside the plasma membrane✓
- D. inside the mitochondrial matrix
Explanation: Option C is correct.Phospholipids arrange themselves in a bilayer in the plasma membrane of a cell. The plasma membrane is a thin, flexible barrier that surrounds the cell and protects it from the external environment. It also controls the movement of molecules into and out of the cell. Phospholipids are amphipathic molecules, meaning that they have a hydrophilic (water-loving) head and a hydrophobic (water-hating) tail. In a bilayer, the hydrophilic heads face the outside and the inside of the cell, while the hydrophobic tails face each other. This arrangement creates a barrier that prevents water and other polar molecules from passing through the plasma membrane. The plasma membrane is a dynamic structure, meaning that it is constantly changing and moving. This is important for a number of cellular processes, such as cell signaling and cell division. The other options are not places where phospholipids arrange themselves in a cell: The nucleus is the central organelle of the cell and contains the cell's DNA. The cytoplasm is the jelly-like substance that fills the cell outside of the nucleus. The mitochondrial matrix is the fluid inside of mitochondria, which are organelles that produce energy for the cell.
Why the other options are wrong
- A. The nucleus is the central control organelle of the cell. It stores the cell’s DNA, which carries all the genetic instructions needed for growth, function, and reproduction. By controlling which genes are active at any time, the nucleus helps regulate nearly all cellular activities.
- B. The cytoplasm is the thick, jelly-like material that occupies the space outside the nucleus. It holds the organelles in place and provides the environment where many of the cell’s chemical reactions take place.
- D. The mitochondrial matrix is the fluid inside of mitochondria, which are organelles that produce energy for the cell.
Q76. Which type of nerve impulse occurs in non-myelinated neuron fibres?
- A. Saltatory impulse
- B. Continuous impulse✓
- C. Rapid impulse
- D. Jumping impulse
Explanation: Option B is correct. The type of nerve impulse that occurs in non-myelinated neuron fibers is a continuous impulse. A continuous impulse is a type of nerve impulse that travels down the axon of a neuron without jumping. This is in contrast to a saltatory impulse, which is a type of nerve impulse that jumps from node to node along the axon of a myelinated neuron. Myelinated neurons are neurons that have a myelin sheath, which is a fatty substance that insulates the axon. The myelin sheath helps to speed up the transmission of nerve impulses by allowing them to jump from node to node. Non-myelinated neurons do not have a myelin sheath, so nerve impulses travel down the axon continuously. This means that nerve impulses travel more slowly in non-myelinated neurons than in myelinated neurons. Saltatory impulse: A type of nerve impulse that jumps from node to node along the axon of a myelinated neuron. Rapid impulse: A type of nerve impulse that travels quickly. Jumping impulse: A type of nerve impulse that jumps from node to node along the axon of a myelinated neuron.
Why the other options are wrong
- A. Saltatory impulse: A type of nerve impulse that jumps from node to node along the axon of a myelinated neuron.
- C. In biology, a "rapid impulse" refers to an action potential, an instantaneous, propagating electrical signal that travels along the membrane of an excitable cell, such as a neuron or muscle cell.
- D. Jumping impulse: A type of nerve impulse that jumps from node to node along the axon of a myelinated neuron.
Q77. In alcoholic fermentation _ ATP Molecules are produced from one glucose molecule:
- A. 2✓
- B. 18
- C. 32
- D. 36
Explanation: Option A is correct. In alcoholic fermentation, two ATP molecules are produced from one glucose molecule. This process occurs in the absence of oxygen and is utilized by yeast and certain microorganisms to convert glucose into ethanol and carbon dioxide. The steps of alcoholic fermentation include:Glycolysis: Glucose is metabolized into two molecules of pyruvate, generating two ATP and two NADH in the process.Pyruvate decarboxylation: Each pyruvate is converted into acetaldehyde, releasing one molecule of carbon dioxide.Alcohol dehydrogenase: Acetaldehyde is then transformed into ethanol, which regenerates NAD+ from NADH.Overall, the net production from one glucose molecule in alcoholic fermentation is two ATP molecules.Options B, C, and D are incorrect as they suggest ATP yields associated with aerobic respiration, which are not applicable in the anaerobic process of alcoholic fermentation.
Why the other options are wrong
- B. This option is incorrect. A maximum of 18 ATP molecules cannot be produced through alcoholic fermentation, as it only yields 2 ATP from one glucose molecule.
- C. This option is incorrect. While 32 ATP molecules can be produced through aerobic respiration, alcoholic fermentation only produces 2 ATP from one glucose molecule.
- D. This option is incorrect. Similar to option C, 36 ATP molecules are associated with aerobic respiration, not alcoholic fermentation, which yields only 2 ATP from one glucose molecule.
Q78. Amino acids mainly differ from each other by the difference in their:
- A. R-group✓
- B. Amino group
- C. Carboxyl group
- D. Hydrogen of alpha carbon
Explanation: Option A is correct.Amino acids mainly differ from each other by the difference in their R-group. The R-group is a side chain that is attached to the alpha carbon of an amino acid. The R-group can be any of 20 different functional groups, which is what gives different amino acids their unique properties. The other options are all common to all amino acids:All amino acids have an amino group (-NH2) attached to their alpha carbon. All amino acids have a carboxyl group (-COOH) attached to their alpha carbon. All amino acids have a hydrogen atom attached to their alpha carbon.
Why the other options are wrong
- B. All amino acids contain an amino group (-NH₂) bonded to their alpha carbon. This amino group is one of the key features that defines an amino acid and helps it link with others to form proteins.
- C. All amino acids also carry a carboxyl group (–COOH) on their alpha carbon. This acidic group is essential for forming peptide bonds and gives amino acids their ability to act as both acids and bases.
- D. All amino acids have a hydrogen atom bonded to their alpha carbon. This hydrogen is part of the basic structure shared by every amino acid, helping define the central framework to which the amino, carboxyl, and side chain groups attach.
Q79. All of the following are related to enzymes except:
- A. Speed up reaction
- B. Remain unchanged after reaction
- C. Increase the activation energy✓
- D. Possess the active site
Explanation: Option C is correct.Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy of the reaction. The activation energy is the amount of energy that must be added to the reactants in order to start the reaction. Enzymes do this by binding to the reactants and forming an enzyme-substrate complex. The enzyme-substrate complex lowers the activation energy of the reaction by stabilizing the transition state not increase activation energy , which is a high-energy intermediate state of the reaction. The other options are all related to enzymes: Speed up reaction: Enzymes speed up chemical reactions by lowering the activation energy of the reaction. Remain unchanged after reaction: Enzymes are catalysts, which means that they remain unchanged after the reaction is complete. Possess the active site: Enzymes have an active site, which is a region of the enzyme that binds to the reactants and catalyzes the reaction.
Why the other options are wrong
- A. Speed up reaction: Enzymes speed up chemical reactions by lowering the activation energy of the reaction.
- B. Remain unchanged after reaction: Enzymes are catalysts, which means that they remain unchanged after the reaction is complete.
- D. Possess the active site: Enzymes have an active site, which is a region of the enzyme that binds to the reactants and catalyzes the reaction.
Q80. The cytoplasm contain(s):
- A. Cell organelle only
- B. Insoluble waste only
- C. Storage products only
- D. Cell organelle, insoluble waste and storage products✓
Explanation: The cytoplasm contains cell organelles, insoluble waste, and storage products. The cytoplasm is the jelly-like substance that fills the cell outside of the nucleus. It is made up of water, proteins, carbohydrates, lipids, and other molecules. The cytoplasm also contains a variety of cell organelles, which are specialized structures that carry out different functions within the cell. Some examples of cell organelles that are found in the cytoplasm include:Mitochondria: Produce energy for the cellEndoplasmic Reticulum: Synthesizes and transports proteins and lipidsGolgi apparatus: Modifies and packages proteins and lipids for secretionRibosomes: Synthesize proteinsCytoskeleton: Provides support and structure to the cellThe cytoplasm also contains insoluble waste products, such as dead organelles and pigments. These waste products are usually stored in vacuoles, which are fluid-filled sacs.Storage products, such as glycogen and starch, are also found in the cytoplasm. These storage products are used by the cell for energy or to build new molecules.
Why the other options are wrong
- A. The cytoplasm is the jelly-like substance that fills the cell outside of the nucleus. It is made up of water, proteins, carbohydrates, lipids, and other molecules. The cytoplasm also contains a variety of cell organelles, which are specialized structures that carry out different functions within the cell. Some examples of cell organelles that are found in the cytoplasm include:Mitochondria: Produce energy for the cellEndoplasmic Reticulum: Synthesizes and transports proteins and lipidsGolgi apparatus: Modifies and packages proteins and lipids for secretionRibosomes: Synthesize proteinsCytoskeleton: Provides support and structure to the cell.
- B. The cytoplasm also contains insoluble waste products, such as dead organelles and pigments. These waste products are usually stored in vacuoles, which are fluid-filled sacs.
- C. Storage products, such as glycogen and starch, are also found in the cytoplasm. These storage products are used by the cell for energy or to build new molecules.
Q81. Tay-Sach's disease particularly results from the malfunctioning of:
- A. Cell membrane
- B. Nucleus
- C. Lysosomes✓
- D. Vacuole
Explanation: Option C is correct.Tay-Sach's disease particularly results from the malfunctioning of lysosomes. Lysosomes are cellular organelles that contain enzymes that break down complex molecules, such as carbohydrates, proteins, and lipids. In Tay-Sach's disease, there is a deficiency of the enzyme hexosaminidase A, which is essential for the breakdown of a fatty substance called GM2 ganglioside. As a result, GM2 ganglioside accumulates in lysosomes, causing damage to nerve cells and other tissues. Tay-Sach's disease is a genetic disorder that is inherited from both parents. It is a rare disease, but it is more common in people of Ashkenazi Jewish descent. There is no cure for Tay-Sach's disease, but there are treatments that can help manage the symptoms and improve the quality of life for people with the disease. The other options are not directly involved in the malfunctioning that causes Tay-Sach's disease: The cell membrane is a barrier that surrounds the cell and protects it from the external environment. The nucleus is the central organelle of the cell and contains the cell's DNA. Vacuoles are fluid-filled sacs that store water, nutrients, and waste products.
Why the other options are wrong
- A. The cell membrane is a barrier that surrounds the cell and protects it from the external environment — this is incorrect. Tay-Sachs disease does not result from a problem with the cell membrane.
- B. This is incorrect. Tay-Sachs disease is not caused by a defect in the nucleus or the cell’s genetic material; the nucleus controls cell activities but is not directly involved in the enzyme deficiency underlying Tay-Sachs.
- D. This is incorrect. Tay-Sachs disease is not caused by a defect in vacuoles; the disease results from a missing or malfunctioning enzyme, not from problems with storage organelles.
Q82. Enzymes present in mammals work best at about:
- A. 20°C
- B. 30°C
- C. 40°C✓
- D. 50°C
Explanation: Option C is correct. Enzymes in mammals typically work best at around 40°C, closely correlating with their normal body temperature of approximately 37°C. At these temperatures, enzymes achieve optimal catalytic efficiency, allowing them to facilitate biochemical reactions at the highest rates. While enzymes can operate at lower and higher temperatures, their activity diminishes as temperatures deviate from this optimal range. Options A (20°C) and B (30°C) are incorrect because they are below the optimal temperature range, leading to reduced enzyme activity. Option D (50°C) is also incorrect, as many mammalian enzymes would likely denature at this temperature, resulting in loss of function. Therefore, understanding the relationship between temperature and enzyme activity is crucial for answering the question correctly.
Why the other options are wrong
- A. This temperature is significantly below the optimal range for most mammalian enzymes. Enzymes generally require higher temperatures to achieve maximum catalytic efficiency, and at 20°C, their activity would be considerably reduced.
- B. While this temperature is closer to the optimal range, it is still below the typical body temperature of mammals. Enzymes may function at this temperature, but they are not likely to reach their maximum activity.
- D. This temperature is generally considered too high for most mammalian enzymes, which can begin to denature and lose functionality at elevated temperatures. While some enzymes can survive higher temperatures, they are not the norm for mammalian enzymes.
Q83. An example of competitive inhibitor molecule is:
- A. Insecticides
- B. Sulphonamide✓
- C. Cyanide
- D. Metal ions
Explanation: Option B is correct.An example of a competitive inhibitor molecule is sulfonamide. Sulfonamides are a class of antibiotics that work by inhibiting the enzyme dihydropteroate synthase. Dihydropteroate synthase is an enzyme that is essential for the synthesis of folic acid, which is a vitamin that is necessary for bacterial growth. Sulfonamides are competitive inhibitors of dihydropteroate synthase because they bind to the active site of the enzyme and prevent the substrate, para-aminobenzoic acid (PABA), from binding. This prevents the synthesis of folic acid and kills the bacteria. The other options are not examples of competitive inhibitors: Insecticides are chemicals that are used to kill insects. They work by a variety of mechanisms, but they do not typically inhibit enzymes. Cyanide is a toxic gas that kills cells by inhibiting the enzyme cytochrome c oxidase. However, it is not a competitive inhibitor because it does not bind to the active site of the enzyme. Metal ions are often used as cofactors for enzymes, but they can also be inhibitors. However, they do not typically act as competitive inhibitors.
Why the other options are wrong
- A. Insecticides are chemicals that are used to kill insects. They work by a variety of mechanisms, but they do not typically inhibit enzymes.
- C. Cyanide is a toxic gas that kills cells by inhibiting the enzyme cytochrome c oxidase. However, it is not a competitive inhibitor because it does not bind to the active site of the enzyme.
- D. Metal ions are often used as cofactors for enzymes, but they can also be inhibitors. However, they do not typically act as competitive inhibitors.
Q84. The ATP formed in the preparatory phase of glycolysis is (are):
- A. 1
- B. 2
- C. 4
- D. 0✓
Explanation: The correct answer is Option D: 0 ATP. In the preparatory phase of glycolysis, two ATP molecules are utilized to phosphorylate glucose and its derivatives, resulting in no ATP being produced during this phase. This phase is essential for priming the glucose molecule for subsequent breakdown in the energy-producing phase, where four ATP molecules are generated. Thus, the net gain of ATP from glycolysis is two ATP per glucose molecule, derived from the four produced in the energy-generating phase minus the two consumed in the preparatory phase.Options A, B, and C are incorrect because they incorrectly imply that ATP is produced in the preparatory phase. Instead, this phase is characterized by an energy investment, where ATP is consumed rather than created.
Why the other options are wrong
- A. This option suggests that one ATP is formed in the preparatory phase, which is incorrect. The preparatory phase actually consumes ATP rather than producing it.
- B. This option indicates that two ATP are formed in the preparatory phase. However, this is also incorrect since the preparatory phase uses two ATP, resulting in zero ATP production at this stage.
- C. This option claims that four ATP are formed in the preparatory phase, which is a misunderstanding of glycolysis. Four ATP are produced in total during glycolysis, but they are generated in the subsequent energy-producing phase.
Q85. Mitochondria are usually absent in:
- A. Muscle cells
- B. Cardiac cells
- C. Mature RBC's✓
- D. WBC's
Explanation: Option C is correct.Mitochondria are usually absent in mature RBC's. Mature RBC's, or erythrocytes, are the most abundant type of blood cell. They are responsible for transporting oxygen from the lungs to the tissues of the body. Mature RBC's are also responsible for removing carbon dioxide from the tissues and transporting it back to the lungs. Mature RBC's do not have mitochondria because they do not need to produce their own energy. They obtain the energy they need from the glucose that is present in the blood. The other options all have mitochondria: Muscle cells: Mitochondria are essential for muscle cells because they provide the energy needed for muscle contraction. Cardiac cells: Cardiac cells, or heart muscle cells, also have mitochondria because they need a lot of energy to pump blood throughout the body. WBC's: WBC's, or white blood cells, have mitochondria because they need energy to fight infection and protect the body from disease
Why the other options are wrong
- A. Muscle cells contain numerous mitochondria because they require large amounts of ATP to fuel continuous contraction and movement.
- B. Cardiac cells, also called cardiomyocytes, contain a large number of mitochondria to meet their high energy demands. These cells contract continuously without rest to pump blood throughout the body, and mitochondria supply the ATP needed for this ongoing activity. The abundance of mitochondria ensures that energy production keeps pace with the constant workload of the heart.
- D. White blood cells (WBCs) contain mitochondria to provide the energy required for their immune functions. They actively move toward infection sites, engulf pathogens through phagocytosis, and produce reactive molecules to destroy invaders, all of which demand significant ATP supplied by mitochondria. This energy enables WBCs to effectively protect the body from disease.
Q86. _ consists of units called dictyosomes
- A. Ribosomes
- B. Lysosomes
- C. Glyoxisomes
- D. Golgi complex✓
Explanation: Option D is correct.he Golgi complex consists of units called dictyosomes. A dictyosome is a stack of flattened sacs called cisternae. The Golgi complex is responsible for processing, modifying, and packaging proteins and lipids for secretion or transport to other parts of the cell. The other options are all cell organelles, but they are not made up of dictyosomes: Ribosomes are the site of protein synthesis. Lysosomes are organelles that contain enzymes that break down complex molecules. Glyoxisomes are organelles that are found in plant cells and are involved in the metabolism of fatty acids.
Why the other options are wrong
- A. Ribosomes are the site of protein synthesis.
- B. Lysosomes are organelles that contain enzymes that break down complex molecules.
- C. Glyoxisomes are organelles that are found in plant cells and are involved in the metabolism of fatty acids.
Q87. The optimal pH of lipase (pancreas) is:
- A. 4.0-5.0
- B. 1.5-1.6
- C. 8.0✓
- D. 6.1-6.8
Explanation: Option C is correct. The optimal pH of lipase (pancreas) is 8.0. This is the pH at which the enzyme is most active and can most efficiently catalyze the breakdown of triglycerides into fatty acids and glycerol. The pancreas secretes lipase into the small intestine, where it helps to digest fats. Lipase is most active in the slightly alkaline environment of the small intestine, which has a pH of around 7.5-8.0. Factors such as the pH of the environment, the temperature, and the presence of bile salts can all affect the activity of lipase. For example, bile salts help to emulsify fats, making them more accessible to lipase. If the pH of the environment is too low (as in Options A and B) or too high (as in Option D), the activity of lipase will be compromised, leading to issues with fat digestion and potential symptoms such as diarrhea and steatorrhea (fatty stools).
Why the other options are wrong
- A. This pH range is too acidic for lipase activity. Lipase, particularly from the pancreas, is not optimally active in this range, which is more suitable for gastric enzymes like pepsin.
- B. This extremely acidic pH is characteristic of the stomach environment and is unsuitable for pancreatic lipase activity, which thrives in more alkaline conditions.
- D. This slightly acidic to neutral range does not provide optimal conditions for pancreatic lipase, which is more active in alkaline environments.
Q88. Consider the reaction below, if 5 moles each of hydrogen and oxygen are reacted to form water, the reaction reveals:2H2 + O2 --> 2H2O
- A. H2 is the excess agent
- B. O2 is the limiting agent
- C. H2 is the limiting reagent✓
- D. The reaction has no limiting reagent
Explanation: Option C is the correct answer. In the reaction 2H2 + O2 --> 2H2O, we start with 5 moles of both hydrogen and oxygen. To find the limiting reagent, we need to calculate how many moles of water can be produced from each reactant:Moles of water from hydrogen: 5 moles H2 * (2 moles H2O / 2 moles H2) = 5 moles H2OMoles of water from oxygen: 5 moles O2 * (2 moles H2O / 1 mole O2) = 10 moles H2OSince hydrogen can produce only 5 moles of water while oxygen could produce 10 moles, hydrogen is the limiting reagent. This means that all of the hydrogen will be consumed in the reaction before all the oxygen is used up, leaving some oxygen unreacted. Thus, the maximum amount of product, which is water, that can be formed is 5 moles.The other options are incorrect because:Option A: Hydrogen is not the excess agent; it is the limiting reagent.Option B: Oxygen is not the limiting agent; it is present in excess.Option D: There is indeed a limiting reagent in this reaction.
Why the other options are wrong
- A. This option is incorrect. Hydrogen (H2) cannot be the excess agent because it limits the amount of product formed, indicating that not all of it will be consumed.
- B. This option is incorrect. Oxygen (O2) is not the limiting agent because there is enough hydrogen to react with the available oxygen, making it the excess reagent.
- D. This option is incorrect. In this reaction, there is a limiting reagent (H2), which will determine the maximum amount of product that can be formed.
Q89. Oxygen can be prepared by the decomposition of potassium chlorate (KClO3). How many moles of oxygen (O2(g)) can be formed by taking 12 moles of potassium chlorate (KClO3) according to the following equation?2KClO3(l) + heat --> 2KCl(s) + 3O2(g)
- A. 12 moles of oxygen
- B. 15 moles of oxygen
- C. 18 moles of oxygen✓
- D. 21 moles of oxygen
Explanation: Option C is correct. The balanced chemical equation is: 2 KClO3(l) + heat → 2 KCl(s) + 3 O2(g). This indicates that for every 2 moles of KClO3, 3 moles of O2 are produced. To find out how many moles of O2 are produced from 12 moles of KClO3, we set up the following calculation: 12 moles KClO3 * (3 moles O2 / 2 moles KClO3) = 18 moles O2. Therefore, the answer is 18 moles of oxygen. The other options are incorrect because they do not align with the stoichiometry of the reaction. Specifically, options A, B, and D propose amounts of O2 that exceed or do not reach the correct product ratio based on the given moles of KClO3.
Why the other options are wrong
- A. This option is incorrect. According to the balanced equation, 2 moles of KClO3 yield 3 moles of O2. Thus, 12 moles of KClO3 would produce more than 12 moles of O2.
- B. This option is also incorrect. The ratio from the balanced equation indicates that 12 moles of KClO3 will yield 18 moles of O2, not 15 moles.
- D. This option is incorrect. The stoichiometry of the reaction does not support the formation of 21 moles of O2 from 12 moles of KClO3. The calculation based on the balanced equation shows that 12 moles KClO3 yield only 18 moles of O2.
Q90. 117.0g of NaCl have
- A. 12.04 x 1023 Formula unit of NaCl✓
- B. 12.04 x 1022 Formula unit of NaCl
- C. 12.04 x 1023 Molecules of NaCl
- D. 6.023 x 1023 Molecules of NaCl
Explanation: Option A is correct.To calculate the number of formula units of NaCl in 117.0g of NaCl, we can use the following steps: Calculate the number of moles of NaCl in 117.0g of NaCl. Multiply the number of moles of NaCl by Avogadro's number (6.022 x 10^23 atoms/mol) to get the number of formula units of NaCl. Step 1: Calculate the number of moles of NaCl in 117.0g of NaCl. The molar mass of NaCl is 58.5g/mol. This means that 1 mole of NaCl weighs 58.5g. Number of moles of NaCl = mass of NaCl / molar mass of NaCl Number of moles of NaCl = 117.0g / 58.5g/mol Number of moles of NaCl = 2.0 moles Step 2: Multiply the number of moles of NaCl by Avogadro's number to get the number of formula units of NaCl. Number of formula units of NaCl = number of moles of NaCl * Avogadro's number Number of formula units of NaCl = 2.0 moles * 6.022 x 10^23 atoms/mol Number of formula units of NaCl = 1204 x 10^23 formula units Therefore, 117.0g of NaCl have 12.04 x 10^23 formula units of NaCl.
Why the other options are wrong
- B. To calculate the number of formula units of NaCl in 117.0g of NaCl, we can use the following steps: Calculate the number of moles of NaCl in 117.0g of NaCl. Multiply the number of moles of NaCl by Avogadro's number (6.022 x 10^23 atoms/mol) to get the number of formula units of NaCl. Step 1: Calculate the number of moles of NaCl in 117.0g of NaCl. The molar mass of NaCl is 58.5g/mol. This means that 1 mole of NaCl weighs 58.5g. Number of moles of NaCl = mass of NaCl / molar mass of NaCl Number of moles of NaCl = 117.0g / 58.5g/mol Number of moles of NaCl = 2.0 moles Step 2: Multiply the number of moles of NaCl by Avogadro's number to get the number of formula units of NaCl. Number of formula units of NaCl = number of moles of NaCl * Avogadro's number Number of formula units of NaCl = 2.0 moles * 6.022 x 10^23 atoms/mol Number of formula units of NaCl = 1204 x 10^23 formula units Therefore, 117.0g of NaCl have 1204 x 10^23 formula units of NaCl.
- C. To calculate the number of formula units of NaCl in 117.0g of NaCl, we can use the following steps: Calculate the number of moles of NaCl in 117.0g of NaCl. Multiply the number of moles of NaCl by Avogadro's number (6.022 x 10^23 atoms/mol) to get the number of formula units of NaCl. Step 1: Calculate the number of moles of NaCl in 117.0g of NaCl. The molar mass of NaCl is 58.5g/mol. This means that 1 mole of NaCl weighs 58.5g. Number of moles of NaCl = mass of NaCl / molar mass of NaCl Number of moles of NaCl = 117.0g / 58.5g/mol Number of moles of NaCl = 2.0 moles Step 2: Multiply the number of moles of NaCl by Avogadro's number to get the number of formula units of NaCl. Number of formula units of NaCl = number of moles of NaCl * Avogadro's number Number of formula units of NaCl = 2.0 moles * 6.022 x 10^23 atoms/mol Number of formula units of NaCl = 1204 x 10^23 formula units Therefore, 117.0g of NaCl have 1204 x 10^23 formula units of NaCl.
- D. To calculate the number of formula units of NaCl in 117.0g of NaCl, we can use the following steps: Calculate the number of moles of NaCl in 117.0g of NaCl. Multiply the number of moles of NaCl by Avogadro's number (6.022 x 10^23 atoms/mol) to get the number of formula units of NaCl. Step 1: Calculate the number of moles of NaCl in 117.0g of NaCl. The molar mass of NaCl is 58.5g/mol. This means that 1 mole of NaCl weighs 58.5g. Number of moles of NaCl = mass of NaCl / molar mass of NaCl Number of moles of NaCl = 117.0g / 58.5g/mol Number of moles of NaCl = 2.0 moles Step 2: Multiply the number of moles of NaCl by Avogadro's number to get the number of formula units of NaCl. Number of formula units of NaCl = number of moles of NaCl * Avogadro's number Number of formula units of NaCl = 2.0 moles * 6.022 x 10^23 atoms/mol Number of formula units of NaCl = 1204 x 10^23 formula units Therefore, 117.0g of NaCl have 1204 x 10^23 formula units of NaCl.
Q91. The number of orientations of a sub – shell for which n= 4 and l= 3 will be:
- A. 5
- B. 3
- C. 7✓
- D. 1
Explanation: Option C is the correct choice. To determine the number of orientations of a sub-shell with quantum numbers n=4 and l=3, we use the formula: Number of orientations = 2l + 1. Here, l=3, so:Number of orientations = 2(3) + 1 = 6 + 1 = 7.Thus, the number of orientations is 7, which corresponds to Option C.Options A, B, and D are incorrect as they fail to apply the formula correctly, leading to lower counts of orientations that do not reflect the quantum mechanical principles governing atomic structure.
Why the other options are wrong
- A. This option suggests that there are 5 orientations. However, this is incorrect because it does not apply the correct formula to calculate the number of orientations based on the azimuthal quantum number.
- B. This option implies there are 3 orientations which is also incorrect. The formula indicates that there should be more orientations for the given values of n and l.
- D. This option suggests there is only 1 orientation, which is not possible for the given values of n and l. Hence, this is incorrect.
Q92. Photon of the lowest wavelength is related to:
- A. Balmer series✓
- B. Pfund series
- C. Bracket series
- D. Paschen series
Explanation: Option A is correct.The photon of the lowest wavelength is related to the Balmer series. The Balmer series is a spectral series in which photons are emitted when an electron in a hydrogen atom transitions from an energy level with a principal quantum number greater than 2 to the energy level with a principal quantum number of 2. The wavelength of the emitted photon is inversely proportional to the difference in energy between the two energy levels. The lowest wavelength in the Balmer series is known as the Balmer alpha line, which has a wavelength of 656.3 nm. This is the wavelength of the photon that is emitted when an electron in a hydrogen atom transitions from the third energy level to the second energy level. The Paschen series corresponds to transitions between the third energy level (n = 3) and higher energy levels (n ≥ 4).The Brackett series corresponds to transitions between the fourth energy level (n = 4) and higher energy levels (n ≥ 5). The Pfund series corresponds to transitions between the fifth energy level (n = 5) and higher energy levels (n ≥ 6).
Why the other options are wrong
- B. The Pfund series corresponds to transitions between the fifth energy level (n = 5) and higher energy levels (n ≥ 6).
- C. The Brackett series corresponds to transitions between the fourth energy level (n = 4) and higher energy levels (n ≥ 5).
- D. The Paschen series corresponds to transitions between the third energy level (n = 3) and higher energy levels (n ≥ 4);
Q93. The maximum e/m ratio for positive rays is obtained when they discharge tube contains:
- A. He
- B. N2
- C. Ne
- D. H2✓
Explanation: Option D is correct. The maximum e/m ratio for positive rays is achieved with H2 because it is the lightest atom, resulting in the highest charge-to-mass ratio. The e/m ratio is defined as the charge of a particle divided by its mass, and it indicates how much a particle is influenced by electric and magnetic fields. A higher e/m ratio means greater deflection in these fields. The other options (He, N2, and Ne) are heavier than hydrogen, which results in lower e/m ratios due to their greater mass. Understanding the e/m ratio is crucial in identifying elements in gases and was pivotal in early atomic research, such as J.J. Thomson's work on the electron's mass.
Why the other options are wrong
- A. Helium (He) is heavier than hydrogen and therefore has a lower e/m ratio. Although it is a noble gas, which means it is stable, its mass is not optimal for achieving the maximum e/m ratio.
- B. Nitrogen (N2) is a diatomic molecule and has a greater mass compared to hydrogen. This additional mass results in a lower e/m ratio, making it less favorable for obtaining the maximum e/m ratio.
- C. Neon (Ne) is also heavier than hydrogen, which means its e/m ratio is lower. As a noble gas, it is stable, but like helium and nitrogen, does not provide the optimal conditions for maximizing the e/m ratio.
Q94. 1 atm of pressure is equal to all of the following except:
- A. 76 cm Hg
- B. 769 mm Hg✓
- C. 760 torr
- D. 101325 Pa
Explanation: Option B is correct.The answer is 769 mm Hg. 1 atm is equal to 760 mm Hg, so 769 mm Hg is slightly greater than 1 atm. All of the other options are equal to 1 atm.
Why the other options are wrong
- A. 76 cm Hg is equal to 1 atm.
- C. 760 torr is equal to 1 atm.
- D. 101325 Pa is equal to 1 atm.
Q95. Volume of a given mass of an ideal gas at certain pressure is x at constant temperature. What will be its volume when the pressure is reduced to half:
- A. 1/2
- B. 2x✓
- C. 4x
- D. 1/4
Explanation: Option B is correct. When the pressure of an ideal gas is reduced to half at a constant temperature, the volume of the gas will double. This relationship is described by Boyle's Law, which states that for a given mass of an ideal gas at constant temperature, the product of pressure (P) and volume (V) is constant (PV = constant). Hence, if the pressure is halved, to maintain the constant product, the volume must double. Therefore, if the initial volume is x, the new volume will be 2x.Option A is incorrect because it suggests the volume reduces to half, which is not in accordance with the principle of gas behavior. Option C is incorrect as it implies that the volume quadruples, which is not true under these conditions. Option D is also incorrect as it indicates a significant reduction in volume, which contradicts the expected increase in volume when pressure decreases.
Why the other options are wrong
- A. This option suggests that the volume reduces to half when the pressure is halved, which is incorrect according to Boyle's Law. When pressure decreases, volume increases.
- C. This option incorrectly suggests that the volume quadruples when the pressure is halved. According to Boyle's Law, volume is directly proportional to the inverse of pressure, resulting in a doubling, not quadrupling, of volume.
- D. This option indicates a drastic reduction in volume, which contradicts the principle that volume increases as pressure decreases. Therefore, it is incorrect.
Q96. The volume occupied by 3.2 g of oxygen gas at S.T.P is:
- A. 1.12 dm3
- B. 2.24 dm3✓
- C. 22.4 dm3
- D. 24 dm3
Explanation: Option B is correct. The volume occupied by 3.2 g of oxygen gas at STP is 2.24 dm3. STP stands for standard temperature and pressure, defined as 0 °C (273.15 K) and 1 atm (101325 Pa). To find the volume of a gas at STP, we use the ideal gas law: PV = nRT. Here, P is the pressure in atm, V is the volume in L, n is the number of moles, R is the ideal gas constant (0.08206 L atm mol-1 K-1), and T is the temperature in K.Given 3.2 g of oxygen, we calculate the moles of oxygen using its molar mass (32 g/mol): n = m / M = 3.2 g / 32 g/mol = 0.1 mol. At STP, we plug the values into the ideal gas law:V = nRT / P = (0.1 mol)(0.08206 L atm mol-1 K-1)(273.15 K) / (1 atm) = 2.24 L. Thus, 2.24 L equals 2.24 dm3.Options A, C, and D are incorrect as they either miscalculate the volume based on the number of moles or present incorrect standard gas volumes.
Why the other options are wrong
- A. This option is incorrect. At STP, 1 mole of an ideal gas occupies 22.4 dm3. The given mass of oxygen (3.2 g) corresponds to only 0.1 moles, which would occupy 2.24 dm3, not 1.12 dm3.
- C. This option is incorrect. 22.4 dm3 is the volume for 1 mole of gas at STP. Since 3.2 g of oxygen is only 0.1 moles, the correct volume is significantly smaller, specifically 2.24 dm3.
- D. This option is incorrect. 24 dm3 does not correspond to any standard gas volume at STP. The correct calculation yields 2.24 dm3 for 3.2 g of oxygen at STP.
Q97. All of the following crystal systems have α=β=γ=90° except:
- A. Cubic
- B. Orthrombic
- C. Tetragonal
- D. Rhombohedral✓
Explanation: Option D is correct.The crystal system that does not have β=γ=90° is rhombohedral. The other three crystal systems, cubic, orthorhombic, and tetragonal, all have the following properties: Cubic: a=b=c, α=β=γ=90° Orthorhombic: a≠b≠c, α=β=γ=90° Tetragonal: a=b≠c, α=β=γ=90° The rhombohedral crystal system, on the other hand, has the following properties: a=b=c, α=β=γ≠90° The angle α=β=γ in the rhombohedral crystal system is typically between 60° and 120°, but it can be outside of this range.
Why the other options are wrong
- A. Cubic: a=b=c, α=β=γ=90°
- B. Orthorhombic: a≠b≠c, α=β=γ=90°
- C. Tetragonal: a=b≠c, α=β=γ=90°
Q98. Compund having lowest boiling point is:
- A. Carbon tetrachloride✓
- B. Ethyl alcohol
- C. Benzene
- D. Acetic acid
Explanation: Option A (Carbon tetrachloride) is correct. It has the lowest boiling point because it is a nonpolar molecule with weak intermolecular London dispersion forces. In contrast, Option B (Ethyl alcohol) has a higher boiling point due to its ability to form hydrogen bonds, which are significantly stronger than dispersion forces. Option C (Benzene) has a higher boiling point than carbon tetrachloride primarily due to stronger π-π interactions despite being nonpolar. Lastly, Option D (Acetic acid) has the highest boiling point in this set due to its ability to form hydrogen bonds, which necessitates more energy to break these interactions during boiling. Hence, all other options have higher boiling points than carbon tetrachloride due to their stronger intermolecular forces.
Why the other options are wrong
- B. Ethyl alcohol is a polar molecule that exhibits hydrogen bonding, a strong type of intermolecular force. This results in a higher boiling point compared to carbon tetrachloride, as more energy is needed to break these interactions.
- C. Benzene is also a nonpolar molecule, but it has a higher boiling point than carbon tetrachloride due to its slightly stronger π-π stacking interactions, which require more energy to overcome.
- D. Acetic acid is a polar molecule that can form hydrogen bonds, resulting in a significant increase in boiling point compared to carbon tetrachloride. The presence of these strong intermolecular forces means that acetic acid will boil at a much higher temperature.
Q99. Which of the following can form Hydrogen bonding with each other?
- A. Methanal and Ethanol
- B. Propane and Ethyl Methyl Ketone
- C. Amine and H2O✓
- D. Acetone and Acetaldehyde
Explanation: Option C is correct. Amines and water can form hydrogen bonds due to the presence of hydrogen atoms attached to the electronegative nitrogen in amines, which can interact with the oxygen in water. This interaction is crucial for many biological and chemical processes.In contrast, Option A (Methanal and Ethanol) cannot bond due to the lack of sufficiently electronegative hydrogen in methanal. Option B (Propane and Ethyl Methyl Ketone) involves nonpolar molecules that do not form hydrogen bonds. Lastly, Option D (Acetone and Acetaldehyde) fails to bond as neither has hydrogen directly bonded to an electronegative atom, preventing hydrogen bonding.
Why the other options are wrong
- A. Methanal (HCHO) and ethanol (C2H5OH) can potentially engage in hydrogen bonding with other molecules due to their polar nature. However, they cannot form hydrogen bonds with each other. In methanal, the hydrogen atom is bonded to a carbon atom, which is not electronegative enough to attract the hydrogen in ethanol, which is bonded to oxygen.
- B. Propane (C3H8) is a nonpolar hydrocarbon, while ethyl methyl ketone (C2H5COCH3) is polar but lacks a hydrogen atom bonded to a highly electronegative atom. Therefore, neither molecule can form hydrogen bonds with one another.
- D. Acetone (C3H6O) and acetaldehyde (C2H4O) are both polar molecules. However, neither has a hydrogen atom directly bonded to a highly electronegative atom like oxygen or nitrogen that would allow them to form hydrogen bonds with each other.
Q100. Identify the molecular formula of Furan:
- A. C4H4O✓
- B. C5H3O
- C. C4H5O
- D. C4H3O
Explanation: Option A is correct. The molecular formula of furan is C4H4O. Furan is a heterocyclic aromatic compound characterized by a five-membered ring comprised of four carbon atoms and one oxygen atom. The oxygen atom is part of the ring structure, contributing to its aromatic properties. Furan has applications in the production of various chemicals, including plastics and pharmaceuticals, and is recognized for its distinctive odor. Option B is incorrect because C5H3O corresponds to furfural, which is a derivative of furan but not the molecular formula for furan itself. Option C is incorrect as C4H5O is the molecular formula for cyclobutanol, a cyclic alcohol, and does not describe furan. Option D is incorrect because C4H3O is not a valid molecular formula for any stable compound, as it suggests that a carbon atom would have fewer than four bonds, which violates the octet rule.
Why the other options are wrong
- B. C5H3O represents furfural, a compound derived from furan, but it does not correspond to the molecular formula of furan itself.
- C. C4H5O is the molecular formula for cyclobutanol, which is a saturated cyclic alcohol and not related to furan.
- D. C4H3O is not a valid molecular formula for any stable compound as it implies that a carbon atom would have fewer than four bonds, which is not possible.
Q101. Haber's process is used for the synthesis of ammonia. The optimum temperature for the Haber process is:
- A. 35-50°C
- B. 130-150°C
- C. 400-450°C✓
- D. 500-600°C
Explanation: Option C is correct. The optimum temperature for the Haber process is 400-450°C. This temperature range strikes a balance between reaction rate and yield. While lower temperatures favor the formation of ammonia, they slow the reaction significantly, making production inefficient. Conversely, higher temperatures increase the reaction rate but diminish the yield due to the equilibrium of the reaction shifting away from ammonia production. At 400-450°C, the reaction is fast enough to be practical, and the yield is high enough to ensure that the process remains economically viable. The Haber process is typically conducted at high pressures (200-400 atm) with an iron catalyst to further enhance ammonia production.
Why the other options are wrong
- A. This temperature range is too low for the Haber process. While lower temperatures favor yield, they significantly slow down the reaction rate, making this option impractical for industrial synthesis of ammonia.
- B. This temperature is also too low for optimal reaction rates in the Haber process. Although it may enhance the yield slightly compared to lower temperatures, it still does not meet the necessary conditions for an efficient ammonia production rate.
- D. This temperature range is too high for the Haber process. While it may increase the reaction rate, it decreases the yield of ammonia significantly due to the equilibrium shift, making it inefficient for industrial use.
Q102. If ionic product is less than Ksp then:
- A. Solution will be saturated
- B. Precipitation will occur
- C. Solution will be super saturated
- D. No precipitation will occur✓
Explanation: Option D is correct. The ionic product is less than the solubility product, meaning the solution contains fewer ions than it could have at equilibrium. There is room for more ions and the saturation point is not reached. As saturation is not attained, therefore, precipitation does not occur. There are insufficient ions to exceed Ksp and form a solid precipitate. ==> Precipitation only occurs when the ionic product exceeds Ksp.
Why the other options are wrong
- A. The solution will not be saturated. When the ionic product is less than Ksp, it indicates that the solution contains fewer ions than it can hold at equilibrium. This means that there is room for more of the ionic compound to dissolve in the solution.
- B. As the ionic product is less than the solubility product, the solution is not saturated. As the solution is not saturated, there are not enough ions to exceed Ksp and trigger the formation of a solid precipitate. => Precipitation ony occurs when the ionic product exceeds Ksp.
- C. Solution will not be saturated, as the solution contains lesser ions then what it can have at equilibrium.
Q103. For 𝚫n=0
- A. Kp=Kn✓
- B. Kp ≠ Kn
- C. Kp>Kn
- D. Kp<Kn
Explanation: When the change in the number of moles of gas during a reaction (Δn\Delta nΔn) is zero, it means that the total number of moles of gaseous reactants equals the total number of moles of gaseous products. In this case, the relationship between the equilibrium constants KpK_pKp (which is based on partial pressures) and KcK_cKc (which is based on concentrations) simplifies to Kp=KcK_p = K_cKp=Kc because the equation Kp=Kc(RT)ΔnK_p = K_c(RT)^{\Delta n}Kp=Kc(RT)Δn results in Kp=KcK_p = K_cKp=Kc when Δn=0\Delta n = 0Δn=0.
Why the other options are wrong
- B. This option suggests that KpK_pKp is not equal to KcK_cKc. However, when Δn=0\Delta n = 0Δn=0, the relationship is actually that they are equal, making this option incorrect.
- C. This option indicates that KpK_pKp is greater than KcK_cKc. Again, this is not true when Δn=0 \Delta n = 0Δn=0 because they are equal under these conditions.
- D. his option indicates that KpK_pKp is less than KcK_cKc. Similar to the previous options, this is also not true when Δn=0 \Delta n = 0Δn=0, as KpK_pKp and KcK_cKc are equal.
Q104. Reaction that follows third order kinetics is:
- A. Decomposition of nitrogen dioxide
- B. Decomposition of hydrogen iodide
- C. Gas phase oxidation of nitric oxide✓
- D. Formation of hydrogen iodide
Explanation: Option C is correct as gas phase oxidation of nitric oxide is a third order reaction. The reaction is as follows: 2NO(g) + O2(g) --> 2NO2(g) This reaction is second order with respect to NO and first order with respect to O2, making the overall order to be 3. Option A and D are second order reaction and option B is a zero order reeaction.
Why the other options are wrong
- A. Decomposition of NO2 is a second order reaction. 2NO2(g) --> 2NO(g) + O2(g)
- B. Decomposition of Hydrogen iodide is a zero order reaction. 2HI(g) --> H2(g) + I2(g)
- D. Formation of hydrogen iodide is a second order reaction. H2(g) + I2(g) --> 2HI(g)
Q105. As compared to exothermic-reaction, formation of activated complex in endothermic reaction requires:
- A. Greater Ea✓
- B. Smaller Ea
- C. Equal Ea
- D. No Ea
Explanation: The correct option is A as the endothermic reactions have a greater activation energy because the products of this reaction have more energy than the reactants. On the otherhand products in exothermic reaction have lesser energy than the reactants, therefore, the activation energy is lesser. The graph is shown below
Why the other options are wrong
- B. Activated complexes in exothermic reactions have a lesser activation energy than in endothermic reactions.
- C. Endothermic reactions have a higher activation energy than exothermic reactions
- D. Endothermic reactions have a higher activation energy than exothermic reactions.
Q106. SI Unit of specific heat capacity is:
- A. Jg-1K-1✓
- B. JK-1
- C. JmolK-1
- D. KJ/mol
Explanation: The correct answer is Jg-1K-1, which is the SI unit of specific heat capacity. Specific heat capacity (c) is defined as the amount of heat energy (in joules) required to raise the temperature of one gram of a substance by one degree Kelvin (or Celsius). Therefore, it is expressed in joules per gram per Kelvin.Option B (JK-1) is incorrect because it lacks the mass component, making it unsuitable for specific heat capacity. Option C (JmolK-1) refers to molar heat capacity, applicable to moles rather than grams, and is thus incorrect for this question. Finally, Option D (KJ/mol) also measures energy but in relation to moles, not grams, and therefore does not represent specific heat capacity.
Why the other options are wrong
- B. This unit represents joules per Kelvin, but it does not account for mass, which is essential in defining specific heat capacity.
- C. This unit is used for molar heat capacity, which measures the heat required to raise the temperature of one mole of a substance by one Kelvin, not one gram.
- D. This unit indicates kilojoules per mole, which is also used for molar heat capacity and does not correspond to specific heat capacity, as it lacks the mass unit in grams.
Q107. Processes involving solid and liquid have their:
- A. 𝚫H=𝚫E +P𝚫V
- B. 𝚫H=P𝚫V
- C. 𝚫H=𝚫E✓
- D. 𝚫H=0
Explanation: Option C is correct as ΔH=ΔE+PΔV and for a process involving solids and/or liqiuds, ΔV≅0. Therefore, 𝚫H=𝚫E. There is a change in the internal energy of the process with the environment.
Why the other options are wrong
- A. There is no change in volume in the processes involving solid and liquid. As 𝚫V= 0, therefore, the whole P𝚫V cancels out leaving us with 𝚫H=𝚫E.
- B. There is no change in volume in the processes involving solid and liquid. As 𝚫V= 0, therefore, the whole P𝚫V cancels out leaving us with 𝚫H=𝚫E. There is a change in the internal energy of the process with the environment.
- D. There is no change in volume in the processes involving solid and liquid. As 𝚫V= 0, therefore, the whole P𝚫V cancels out leaving us with 𝚫H=𝚫E. There is a change in the internal energy of the process with the environment.
Q108. In the redox reaction of SO2 with KMnO4 for an acidic medium:
- A. SO2 oxidizes KMnO4
- B. SO2 reduces KMnO4✓
- C. KMnO4 is inert in acidic medium
- D. SO2 can't undergo redox reaction
Explanation: Option B is correct as SO2 is a strong reducing agent and KMnO4 is a strong oxidising agent. SO2 reduces Mn7+ in KMnO4 to Mn2+ and gets oxidised itself from S4+ to S6+.
Why the other options are wrong
- A. SO2 is a strong reducing agent and reduces Mn7+ in KMnO4 Mn2+.
- C. KMnO4 is a strong oxidising agent in its acidic medium.
- D. This reaction undergoes redox reaction where S in SO2 gets oxidised and Mn in KMnO4 gets reduced.
Q109. Zinc displaces copper from its solution because:
- A. Atomic number of zinc is higher than that of copper
- B. Zinc has higher reduction potential than copper
- C. Zinc is more soluble
- D. Zinc has smaller reduction potential than copper✓
Explanation: Option D is correct because zinc’s smaller reduction potential (-0.76V) compared to copper’s (+0.34V) signifies that zinc is more reactive. In electrochemical terms, a metal with a lower reduction potential can displace a metal with a higher reduction potential from its compound in solution. Therefore, zinc can easily displace copper from its solution. Option A is incorrect because the atomic number does not dictate the reactivity of metals. Option B misstates the relationship between the reduction potentials, as zinc's is lower than that of copper. Option C, while potentially true in some contexts, does not pertain to the displacement reaction, as reactivity is the determining factor.
Why the other options are wrong
- A. This option is incorrect because the atomic number does not determine the ability of one metal to displace another from solution. Displacement reactions depend on the reactivity of the metals, which is better indicated by their reduction potentials.
- B. This statement is incorrect. Zinc actually has a lower reduction potential (-0.76V) compared to copper (+0.34V), meaning zinc is less likely to gain electrons and more likely to lose them, which enables it to displace copper from its solution.
- C. This option does not directly relate to the displacement reaction. Solubility does not determine the ability of metals to displace one another in electrochemical reactions; it is the reactivity and reduction potential that matter.
Q110. The molecular shape of a molecule with three bonded atoms and one lone pair electron on the central atom will be:
- A. Trigonal planar
- B. Tetrahedral
- C. Trigonal Pyramidal✓
- D. Linear
Explanation: Option C is correct. If there are three bond pairs and one lone pair of electrons then the molecular shape of that molecule is trigonal pyramidal. An example of such a molecule is NH3. Its geometrical structure is given below. Trigonal planar = 3 bond pairs. Tetrahedral = 4 bond pairs. linear = 2 bond pairs.
Why the other options are wrong
- A. Trigonal planar structure is observed when there are only 3 bond pairs. For example BF3.
- B. Tetrahedral structure is present when there are 4 bond pairs. For example CH4.
- D. Linear structure is present when there are 2 bond pairs. For example CO2.
Q111. Molecule are having the highest bond energy (experimentally) is:
- A. HCl
- B. HF✓
- C. HBr
- D. HI
Explanation: The correct option is B as the decreasing order of bond dissociation energy is HF > HCl > HBr > HI. There is a large difference between electronegativity of H and F, so the bond is stronger. As we go down the group, the difference between electronegativity decreases and therefore, bond dissociation energy also decreases.
Why the other options are wrong
- A. As we go down the group, the difference between the electronegativities decreases. Therefore, HCl requires lesser energy than HF to dissociate.
- C. As we go down the group, the difference between the electronegativities decreases. Therefore, HBr requires lesser energy than HF and HCl to dissociate.
- D. As we go down the group, the difference between the electronegativities decreases. Therefore, HI requires lesser energy than HF, HCl and HBr to dissociate.
Q112. The bond length between double-bonded carbon atom is:
- A. 1.34A°✓
- B. 1.10A°
- C. 1.54A°
- D. 1.82A°
Explanation: The bond length between double-bonded carbon atoms is 1.34A°, which reflects the nature of double bonds being shorter due to increased electron density between the bonded atoms. In contrast, the other options represent lengths that are not characteristic of double bonds: 1.10A° is too short and would suggest a triple bond; 1.54A° is more aligned with a single bond; and 1.82A° is even longer, indicating a weaker single bond. Therefore, 1.34A° is the only correct answer for the bond length of double-bonded carbon.
Why the other options are wrong
- B. This bond length is too short for a double bond. Such a length is more characteristic of triple bonds or very strong interactions, which do not apply here.
- C. This bond length is longer than the typical bond length for double-bonded carbon atoms, which suggests a single bond or a weaker interaction.
- D. This value is significantly longer than expected for double bonds, indicating it is more typical of single bonds, thus incorrect for this context.
Q113. Who is the element that forms normal oxide only
- A. Li✓
- B. Na
- C. K
- D. Rb
Explanation: When Lithium is heated in air it only forms Li2O which is a normal oxide as it contains an O2- ion. On the other hand sodium, potassium and rubidium do not readily form normal oxides when heated in air. They tend to form per and superoxides with charges -1 and -1/2 on oxygen respectively.
Why the other options are wrong
- B. Sodium when heated does not readily form normal oxides. It mostly forms peroxides(Na2O2) or superoxides(NaO2).
- C. Potassium when heated does not readily form normal oxides. It mostly forms peroxides(K2O2) or superoxides(KO2).
- D. Rubidium when heated does not readily form normal oxides. It mostly forms peroxides(Rb2O2) or superoxides(RbO2).
Q114. Element whose salt do not impart colour to flame test is:
- A. Be✓
- B. Cs
- C. Ca
- D. K
Explanation: Option A is correct as Beryllium is one of the 2 alkaline earth metals that does not impart colour to flame test. Cs gives violet flame, Ca gives brick red flame and K gives lilac flames to flame test.
Why the other options are wrong
- B. Cesium gives violet flame to flame test.
- C. Calcium gives brick red flames to flame test.
- D. Potassium gives lilac flame to flame test.
Q115. Indicate superoxide in the following
- A. CaO
- B. BaO2
- C. Na2O2
- D. RbO2✓
Explanation: Option D is correct. In superoxides oxygen has a charge of -1/2 which is the case in option D. All the rest of the options are normal(-2) or per(-1) oxides.
Why the other options are wrong
- A. This a normal oxide of calcium as oxygen has a charge of -2.
- B. This is a peroxide of barium as oxygen has a charge of -1.
- C. This compound is a peroxide of sodium as oxygen has a charge of -1.
Q116. Which one of the following is covalent in nature?
- A. Mg3N2
- B. Be3N2✓
- C. Ca3N2
- D. Ba3N2
Explanation: Be3N2 is a covalent compound as Be and N have a small difference in electronegativity atoms and are more likely to share electrons rather then transferring them from one to another. All other compounds have a greater difference in electronegativity between the atoms making them polar and ionic.
Why the other options are wrong
- A. There is a greater difference between the electronegativity of Mg and N making it polar and an ionic compound rather than a covalent compound.
- C. There is a greater difference between the electronegativity of Ca and N making it polar and an ionic compound rather than a covalent compound.
- D. There is a greater difference between the electronegativity of Ba and N making it polar and an ionic compound rather than a covalent compound.
Q117. Which one has one unpaired electron in the valance shell?
- A. Zn+2
- B. Cu+
- C. Ti+3✓
- D. Fe+3
Explanation: Titanium has an atomic number of 22, and its electron configuration is [Ar]3d24s2[Ar] 3d^{2} 4s^{2}[Ar]3d24s2. Upon losing three electrons to become Ti³⁺, it loses the two 4s electrons and one 3d electron, resulting in [Ar]3d1[Ar] 3d^{1}[Ar]3d1. This means Ti³⁺ has one unpaired electron in its valence shell.
Why the other options are wrong
- A. Zinc has an atomic number of 30, and its electron configuration is [Ar]3d104s2[Ar] 3d^{10} 4s^2[Ar]3d104s2. When it loses two electrons to become Zn²⁺, it loses the two 4s electrons, resulting in a configuration of [Ar]3d10[Ar] 3d^{10}[Ar]3d10. This configuration has no unpaired electrons, as all d-orbitals are fully filled.
- B. Copper has an atomic number of 29, with an electron configuration of [Ar]3d104s1[Ar] 3d^{10} 4s^1[Ar]3d104s1. When it loses one electron to form Cu⁺, it loses the 4s electron, resulting in a configuration of [Ar]3d10[Ar] 3d^{10}[Ar]3d10. However, since Cu⁺ is formed directly from Cu in a typical oxidation state context, the initial 3d orbitals have one unpaired electron remaining.
- D. Iron has an atomic number of 26, with an electron configuration of [Ar]3d64s2[Ar] 3d^{6} 4s^{2}[Ar]3d64s2. When it loses three electrons to form Fe³⁺, it first loses the two 4s electrons and one 3d electron, resulting in [Ar]3d5[Ar] 3d^{5}[Ar]3d5. In this case, Fe³⁺ has five unpaired electrons in its valence shell.
Q118. The oxidation number of cobalt in the given coordination complex is:[Co(H2NCH2CH2NH2)3]2(SO4)3
- A. III✓
- B. II
- C. IV
- D. VI
Explanation: In the given complex, [Co(H2NCH2CH2NH2)3]2(SO4)3 Cobalt is bonded with three molecules of ethylenediamine which is a bidendate ligand having neutral charge. Moreover the coordination sphere is bonded with three molecules of sulphate ions each having -2 charge. Using formula: Charge of Metal + Charge on Ligand + Charge on coordination sphere 2(x + 3(0) ) = 3(-2) 2x = -6 x = -3
Why the other options are wrong
- B. In the given complex, [Co(H2NCH2CH2NH2)3]2(SO4)3 Cobalt is bonded with three molecules of ethylenediamine which is a bidendate ligand having neutral charge. Moreover the coordination sphere is bonded with three molecules of sulphate ions each having -2 charge. Using formula: Charge of Metal + Charge on Ligand + Charge on coordination sphere 2(x + 3(0) ) = 3(-2) 2x = -6 x = -3
- C. In the given complex, [Co(H2NCH2CH2NH2)3]2(SO4)3 Cobalt is bonded with three molecules of ethylenediamine which is a bidendate ligand having neutral charge. Moreover the coordination sphere is bonded with three molecules of sulphate ions each having -2 charge. Using formula: Charge of Metal + Charge on Ligand + Charge on coordination sphere 2(x + 3(0) ) = 3(-2) 2x = -6 x = -3
- D. In the given complex, [Co(H2NCH2CH2NH2)3]2(SO4)3 Cobalt is bonded with three molecules of ethylenediamine which is a bidendate ligand having neutral charge. Moreover the coordination sphere is bonded with three molecules of sulphate ions each having -2 charge. Using formula: Charge of Metal + Charge on Ligand + Charge on coordination sphere 2(x + 3(0) ) = 3(-2) 2x = -6 x = -3
Q119. Pyrole belongs to which class of compounds?
- A. Hydrocarbons
- B. Homocyclic
- C. Alicyclic
- D. Heterocyclic✓
Explanation: Pyrole is a heterocyclic compound. Heterocyclic compounds are organic compounds with a ring structure that contains in the cycle at least one carbon atom and at least one other element, such as N, O, or S.
Why the other options are wrong
- A. Hydrocarbons are compounds made only of carbon and hydrogen atoms. Pyrrole doesn’t fit in this category because it contains nitrogen in its ring, so it isn’t a true hydrocarbon.
- B. Homocyclic compounds are those whose ring is made up of the same type of atoms, usually all carbon atoms. This means the entire ring is formed only by carbon, with no other elements included.
- C. Alicyclic compounds are ring structures made up of at least three carbon atoms. They resemble aliphatic compounds in behavior but have a closed-ring arrangement.
Q120. Ethyl alcohol in the presence of H2SO4 at 170°C produces
- A. Ether
- B. Ethene✓
- C. Ester
- D. Ethane
Explanation: When ethyl alcohol reacts with H2SO4 at high temperature, beta elimination takes place resulting in formation of ethene.
Why the other options are wrong
- A. When ethyl alcohol reacts with H2SO4 at high temperature, beta elimination takes place resulting in formation of ethene.
- C. When ethyl alcohol reacts with H2SO4 at high temperature, beta elimination takes place resulting in formation of ethene.
- D. When ethyl alcohol reacts with H2SO4 at high temperature, beta elimination takes place resulting in formation of ethene.
Q121. Lindlar's catalyst is used in hydrogenation of alkyne:
- A. To increase activation energy
- B. To enhance hydrogenation of alkene
- C. To produce cis alkene✓
- D. To start polymerisation reaction
Explanation: Lindlar's catalyst is specifically designed for the partial hydrogenation of alkynes to form cis-alkenes. It does this by providing a controlled environment where hydrogenation occurs without over-reduction to alkanes, ensuring the formation of the cis configuration.
Why the other options are wrong
- A. Lindlar's catalyst is not used to increase activation energy. In fact, catalysts lower the activation energy required for a reaction to proceed, thereby enhancing the reaction rate.
- B. While Lindlar's catalyst can facilitate hydrogenation reactions, its primary purpose is not to enhance the hydrogenation of alkenes. Instead, it specifically targets alkynes to produce cis alkenes.
- D. Lindlar's catalyst is not used to initiate polymerization reactions. Its role is focused on hydrogenation, particularly in transforming alkynes to cis alkenes, rather than promoting polymerization processes.
Q122. Which one of the following is not meta directing group?
- A. -COR
- B. -NO2
- C. -CHO
- D. -NR2✓
Explanation: Examples of meta– directors include nitriles, carbonyl compounds (such as aldehydes, ketones, and esters), sulfones, electron-deficient alkyl groups, nitro groups, and alkylammoniums. While examples of ortho-, para– directors are hydroxyl groups, ethers, amines, alkyl groups, thiols, and halogens.
Why the other options are wrong
- A. Examples of meta– directors include nitriles, carbonyl compounds (such as aldehydes, ketones, and esters), sulfones, electron-deficient alkyl groups, nitro groups, and alkylammoniums. While examples of ortho-, para– directors are hydroxyl groups, ethers, amines, alkyl groups, thiols, and halogens.
- B. Examples of meta– directors include nitriles, carbonyl compounds (such as aldehydes, ketones, and esters), sulfones, electron-deficient alkyl groups, nitro groups, and alkylammoniums. While examples of ortho-, para– directors are hydroxyl groups, ethers, amines, alkyl groups, thiols, and halogens.
- C. Examples of meta– directors include nitriles, carbonyl compounds (such as aldehydes, ketones, and esters), sulfones, electron-deficient alkyl groups, nitro groups, and alkylammoniums. While examples of ortho-, para– directors are hydroxyl groups, ethers, amines, alkyl groups, thiols, and halogens.
Q123. Benzene-1,3-diol is also known as:
- A. Catechol
- B. Resorcinol✓
- C. Hydroquinone
- D. O-cersol
Explanation: Resorcinol is a 1,3-isomer (or meta-isomer) of benzenediol with the formula C6H4(OH)2.
Why the other options are wrong
- A. Catechol, also known as pyrocatechol or 1,2-dihydroxybenzene, is an organic compound essentially used as building block.
- C. Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2
- D. ortho-Cresol (IUPAC name: 2-methylphenol, also known as 2-hydroxytoluene or ortho-Toluenol) is an organic compound with the formula CH3C6H4(OH).
Q124. Identify the electrophile as acylium ion:
- A. RNa+
- B. RCO+✓
- C. RCOO+
- D. RNO+
Explanation: Acylium ions are cations of the formula RCO +. The carbon–oxygen bond length in these cations is near 1.1 Å (110-112 pm), which is shorter than the 112.8 pm of carbon monoxide and indicates triple-bond character.
Why the other options are wrong
- A. RNa+ is also known as sodium ion.
- C. RCOO+ is known as carboxylate ion.
- D. RNO+ is known as nitrosonium ion.
Q125. Among the following hydrocarbons which one has acidic hydrogen?
- A. C2H6
- B. C2H4
- C. C2H2✓
- D. C3H6
Explanation: In alkynes,terminal alkyne has acidic hydrogen due to the high level of s character in the sp hybrid orbital, which bonds with the s orbital of the hydrogen atom to form a single covalent bond.
Why the other options are wrong
- A. The given compound is an alkane. The alkanes do not have acidic hydrogen.
- B. The given compound is an alkene. The alkenes do not have acidic hydrogen.
- D. The given compound is an alkene. The alkenes do not have acidic hydrogen.
Q126. Greater number of Alkyl groups on substrate favours:
- A. Substrate reaction
- B. Elimination reaction✓
- C. Oxidation reaction
- D. Free radical reaction
Explanation: A greater number of alkyl groups on a substrate favors elimination reactions because it leads to the formation of more stable and substituted double bonds, reduces steric hindrance, enhances hyperconjugation, and stabilizes the transition state of the elimination reaction.
Why the other options are wrong
- A. A substrate with fewer alkyl groups favors substitution reactions because it is less hindered, more electrophilic, and the leaving group is less stabilized, making it more susceptible to nucleophilic attack.
- C. Oxidation reactions are favored under conditions that provide oxidizing agents, high temperatures, and certain catalysts. These conditions promote the loss of electrons or an increase in the oxidation state of a substance.
- D. Free radical reactions are favored under conditions involving heat, light (especially UV light), peroxides, initiators, high temperatures, non-polar solvents, and the presence of oxygen. These conditions promote the generation and stability of free radicals, initiating and sustaining free radical reactions.
Q127. SN1 reactions mostly result in partial racemization, in partial racemization there is:
- A. Inversion only
- B. Retention only
- C. Equal inversion and retention
- D. More inversion and retention✓
Explanation: In SN1 reactions, the formation of a planar carbocation allows for nucleophilic attack from either side, resulting in both inversion and retention. However, due to steric factors and the nature of the nucleophile, there tends to be more inversion than retention, leading to a mixture of products with both configurations, thus resulting in partial racemization.
Why the other options are wrong
- A. Inversion refers to the configuration change that occurs when the nucleophile attacks the planar carbocation from the opposite side of the leaving group. However, in SN1 reactions, both inversion and retention of configuration can occur, so this option is not accurate.
- B. Retention occurs when the nucleophile attacks from the same side as the leaving group. While this can happen in SN1 reactions, it is not the only outcome. Therefore, this option does not represent the overall outcome of SN1 reactions.
- C. While both inversion and retention can occur in SN1 reactions, they do not occur in equal amounts. The proportion of inversion and retention may depend on factors such as steric hindrance, but they do not happen equally.
Q128. Which of the following involves the same steps?
- A. E1 and E2
- B. E1 and SN1✓
- C. SN1 and SN2
- D. E2and SN1
Explanation: E1 (unimolecular elimination) and SN1 (unimolecular nucleophilic substitution) both involve the same first step: the formation of a carbocation after the leaving group departs. After that, E1 leads to elimination (forming a double bond), and SN1 involves nucleophilic substitution.
Why the other options are wrong
- A. E1 and E2 mechanisms are different in terms of their steps. E1 is a two-step mechanism where the leaving group departs first to form a carbocation, followed by deprotonation. E2, on the other hand, is a one-step concerted mechanism where the leaving group departs and deprotonation occurs simultaneously.
- C. SN1 is a two-step mechanism with carbocation formation, while SN2 is a one-step concerted mechanism where the nucleophile attacks as the leaving group departs. Therefore, they do not involve the same steps.
- D. E2 is a one-step elimination mechanism, whereas SN1 is a two-step substitution mechanism involving a carbocation. They differ in their processes, so they don't share the same steps.
Q129. The correct sequence of electronic configuration is:
- A. 4p 5s 4d 5p 6s 4f 5d✓
- B. 4p 4s 4d 5p 5s 5f 6d
- C. 4p 4s 4d 5p 5s 4f 5d
- D. 4p 3s 4d 5p 6s 4f 5d
Explanation: This sequence follows the correct order of filling orbitals according to the Aufbau principle. The orbitals are filled in the increasing order of their energy levels, and this sequence correctly reflects the way electrons occupy these orbitals (4p → 5s → 4d → 5p → 6s → 4f → 5d).
Why the other options are wrong
- B. In this sequence, the order of 4s and 4p is wrong; 4s fills before 4p, and 5f appears out of place (it comes after 6s, not before it).
- C. This option places 4s after 4p, which is incorrect because 4s should fill before 4p. Also, the sequence of 5p and 5s is incorrect, as 5s fills before 5p.
- D. The placement of 3s after 4p is wrong because the 3s orbital is filled much earlier than the 4p orbital. The rest of the sequence after 4p is not aligned with the correct energy filling order.
Q130. When phenol reacts with excess of bromine in aqueous solution it results in the formation of:
- A. Ortho/para bromophenol
- B. Meta bromophenol
- C. 2,4,6-Tribromophenol✓
- D. 3,5-Dibromophenol
Explanation: An aqueous solution of phenol reacts with bromine water to give white ppt. of 2,4,6- tribromophenol.
Why the other options are wrong
- A. An aqueous solution of phenol reacts with bromine water to give white ppt. of 2,4,6- tribromophenol.
- B. An aqueous solution of phenol reacts with bromine water to give white ppt. of 2,4,6- tribromophenol.
- D. An aqueous solution of phenol reacts with bromine water to give white ppt. of 2,4,6- tribromophenol.
Q131. Propylene glycol and trimethylene glycol are:
- A. Functional group isomers
- B. Metamers
- C. Position isomers✓
- D. Tautomers
Explanation: Propylene glycol and trimethylene glycol are positional isomers. In positional isomers, the same molecular formula is retained, but the functional groups or substituents are attached at different positions on the carbon chain. Both of these compounds are diols (containing two hydroxyl groups), but the positioning of the hydroxyl groups differs, which gives them distinct properties.
Why the other options are wrong
- A. Functional group isomers are compounds that have the same molecular formula but differ in the type of functional group present. This results in different chemical and physical properties, even though the total number of atoms remains the same.
- B. Metamers are a type of structural isomer where compounds have the same molecular formula but differ in the arrangement of alkyl groups on either side of a functional group, such as an oxygen atom, sulfur atom, or nitrogen atom.
- D. Tautomers are a specific type of isomers that rapidly interconvert by the movement of atoms, usually hydrogen atoms, and a change in the position of double bonds. This dynamic equilibrium between two forms is called tautomerism. The most common type of tautomerism is keto-enol tautomerism,
Q132. The reduction of aldehyde and ketone is to alkanes in the presence of Zinc amalgam and HCl is called
- A. Clemmensen reduction✓
- B. Williamson's synthesis
- C. Wolf-Kishner reduction
- D. Dow process
Explanation: Clemmensen reduction is a chemical reaction described as a reduction of ketones or aldehydes to alkanes using zinc amalgam and concentrated hydrochloric acid.
Why the other options are wrong
- B. The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol.
- C. The Wolff-Kishner Reduction is a method to reduce aldehydes and ketones into alkanes. It is used explicitly for aldehydes and ketones attached to a benzene ring. The reactants of the Wolff-Kishner reaction include the aldehyde or ketone to be reduced, hydrazine, and a base (with heat).
- D. Dow process (bromine), a method of bromine extraction from brine. Dow process (magnesium), a method of magnesium extraction from brine. Dow process (phenol), a method of phenol production through the hydrolysis of chlorobenzene.
Q133. Aldehyde and ketone on reaction with hydroxylamine form:
- A. Hydrazine
- B. Hydrazone
- C. Oxime✓
- D. Imine
Explanation: When aldehydes and ketones react with hydroxylamine (NH₂OH), they form a class of compounds known as oximes. The reaction involves the nucleophilic addition of hydroxylamine to the carbonyl group (C=O) of the aldehyde or ketone, resulting in the formation of an oxime, which contains the functional group C=N-OH.
Why the other options are wrong
- A. This is incorrect. Hydrazine (N₂H₄) is a separate compound and not a product of the reaction between hydroxylamine and aldehydes or ketones.
- B. This option is incorrect. Hydrazones are formed when aldehydes or ketones react with hydrazine (not hydroxylamine) and result in the C=N-NH₂ functional group.
- D. This is incorrect in the context of the reaction with hydroxylamine. Imine formation typically involves the reaction of an aldehyde or ketone with a primary amine (RNH₂), leading to the C=N-R functional group.
Q134. Fehling's solution works on the principle of redox reaction which results in:
- A. Reduction of aldehydes
- B. Oxidation of Copper(II)
- C. Oxidation of aldehyde✓
- D. Oxidation of Ketone
Explanation: Fehling's solution is specifically designed to test for aldehydes, which are oxidized to carboxylic acids during the reaction. In this process, the Cu²⁺ ions from the Fehling's solution are reduced to Cu₂O, which precipitates as a red solid. Therefore, the correct answer is the oxidation of aldehyde. The other options are incorrect as they either misinterpret the nature of the reaction (like reduction of aldehydes) or focus on the wrong substrate (ketones), which do not react under these conditions. While copper(II) is involved in the reaction, the key reaction occurring is the oxidation of the aldehyde itself.
Why the other options are wrong
- A. This option is incorrect because aldehydes undergo oxidation, not reduction, when reacted with Fehling's solution.
- B. This option, while true in that copper(II) is reduced during the reaction, does not address the primary reaction of interest, which is the oxidation of the aldehyde.
- D. This option is incorrect. Ketones do not typically react with Fehling's solution as they are more resistant to oxidation compared to aldehydes.
Q135. In conversion of acid halides to Ester, pyridine is used to:
- A. Stabilize acid halides
- B. Consume HCl formed in the reaction✓
- C. Dehydrate alcohol
- D. Dehydrogenate acid halides
Explanation: This option is correct. During the reaction of acid halides with alcohols to form esters, hydrogen halide (such as HCl) is released as a byproduct. Pyridine, being a weak base, reacts with the HCl to form pyridinium chloride, effectively neutralizing the acid. This helps to shift the reaction equilibrium toward the formation of the ester.
Why the other options are wrong
- A. This option is incorrect. Pyridine does not stabilize acid halides; rather, it facilitates their reaction with alcohols by acting as a base. Acid halides are generally reactive compounds, and pyridine's role is not to stabilize them but to help convert them to esters.
- C. This option is incorrect. Pyridine does not dehydrate alcohols in this reaction. Dehydration refers to the removal of water from a compound, and in the context of this reaction, pyridine does not play a role in removing water. The alcohol is used in its typical state for the esterification process.
- D. This option is incorrect. Dehydrogenation refers to the removal of hydrogen from a compound, and pyridine does not dehydrogenate acid halides in this reaction. The focus of the reaction is on the conversion of acid halides to esters, not on altering the hydrogen content of the acid halides.
Q136. Number of carbon atoms in valeric acid is:
- A. 4
- B. 5✓
- C. 6
- D. 7
Explanation: Valeric acid is a carboxylic acid with the IUPAC name pentanoic acid. It consists of a straight chain of 5 carbon atoms (C5H10O2), which is why the correct answer is 5. The other options are incorrect because:4 carbon atoms would correspond to butanoic acid, which is different.6 carbon atoms would correspond to hexanoic acid, which also does not fit.7 carbon atoms would correspond to heptanoic acid, which is not valeric acid.Thus, the only valid option is 5, as it accurately reflects the number of carbon atoms in valeric acid.
Why the other options are wrong
- A. This option is incorrect. Valeric acid has 5 carbon atoms, not 4.
- C. This option is incorrect. A 6-carbon carboxylic acid would be hexanoic acid, not valeric acid.
- D. This option is also incorrect. Valeric acid does not have 7 carbon atoms; that would correspond to heptanoic acid.
Q137. The IUPAC name of formyl chloride is:
- A. Methanoic acid
- B. Chloro methane
- C. Methanoyl chloride✓
- D. Chloro methanoate
Explanation: The correct IUPAC name for formyl chloride is Methanoyl chloride. This name indicates that the compound is derived from methane (the simplest alkane with one carbon) with a carbonyl group (C=O) and a chlorine atom attached. The prefix 'formyl' corresponds to the presence of the aldehyde functional group, which is equivalent to the methanoyl structure. The other options are incorrect for the following reasons: - Chloro methanoic acid implies the presence of a carboxylic acid group, which is not present in formyl chloride. - Chloro methane suggests a chlorinated methane without considering the carbonyl group, leading to an insufficient description of the compound. - Chloro methanoate implies an ester structure, which is also incorrect as there is no alcohol component in formyl chloride.
Why the other options are wrong
- A. This name suggests a carboxylic acid structure, which is incorrect because formyl chloride contains a carbonyl group (C=O) bonded to a chlorine and is not an acid.
- B. This name implies a simple chlorinated methane, which does not account for the carbonyl group present in formyl chloride. It is not the correct naming for this compound.
- D. This name suggests an ester, which is not the case for formyl chloride. The presence of the carbonyl group does not lead to an ester formation in this compound.
Q138. The inhibition, in which the inhibitor does not combine directly with the enzyme but binds to the enzyme-substrate complex is called:
- A. Reversible inhibition
- B. Competitive inhibition
- C. Non-Competitive inhibition
- D. Uncompetitive inhibition✓
Explanation: The correct answer is Uncompetitive inhibition. This type of inhibition specifically involves the inhibitor binding to the enzyme-substrate complex, preventing the formation of products. In contrast, Reversible inhibition is a broader category that includes various forms of inhibition not limited to the enzyme-substrate complex. Competitive inhibition is characterized by the inhibitor directly competing with the substrate for the active site, while Non-Competitive inhibition refers to the inhibitor binding to a different site on the enzyme, not the enzyme-substrate complex. Therefore, uncompetitive inhibition is the only option that directly addresses the relationship between the inhibitor and the enzyme-substrate complex.
Why the other options are wrong
- A. Reversible inhibition refers to a scenario where the inhibition of enzyme activity can be undone by removing the inhibitor or by increasing substrate concentration. This type encompasses various mechanisms, but it does not specifically address the binding to the enzyme-substrate complex.
- B. Competitive inhibition occurs when an inhibitor competes directly with the substrate for the active site on the enzyme. This means that the inhibitor and substrate cannot bind simultaneously to the active site, making it distinct from the binding to the enzyme-substrate complex.
- C. Non-competitive inhibition involves an inhibitor binding to an allosteric site on the enzyme, which can occur whether or not the substrate is bound. While it describes a different mode of inhibition, it does not specify binding to the enzyme-substrate complex.
Q139. Trypsinogen can be activated by the action of:
- A. Amylase
- B. HCl
- C. Glucokinase
- D. Entrokinase✓
Explanation: Trypsinogen is a zymogen (inactive enzyme precursor) that requires activation to become trypsin, an active enzyme essential for protein digestion. The activation occurs primarily in the small intestine, where enteropeptidase (also known as entero kinase) converts trypsinogen into trypsin. This process is crucial for initiating the digestive cascade, as trypsin can further activate other digestive enzymes. Amylase, HCl, and glucokinase do not play a role in this specific activation process. Amylase is involved in carbohydrate digestion, HCl aids in protein denaturation and creates an acidic environment for enzymes, while glucokinase is related to glucose metabolism.
Why the other options are wrong
- A. Amylase is an enzyme that breaks down carbohydrates into sugars, and it does not play a role in the activation of trypsinogen.
- B. Hydrochloric acid (HCl) is involved in the gastric environment but does not directly activate trypsinogen. It helps create the optimal pH for enzyme activity.
- C. Glucokinase is an enzyme that facilitates glucose phosphorylation, and it is unrelated to the activation of trypsinogen.
Q140. Crystal having orthorhombic crystal system is:
- A. PbCrO4
- B. BaSO4✓
- C. ZnO
- D. NaOH
Explanation: The correct answer is Barium sulfate (BaSO₄), which crystallizes in the orthorhombic crystal system. This system has three mutually perpendicular axes that are of unequal lengths, a characteristic feature of orthorhombic crystals.In contrast, Lead chromate (PbCrO₄) is not correct as it belongs to the tetragonal system, characterized by one axis being longer than the other two, which are equal in length. Zinc oxide (ZnO) is classified under the hexagonal system, which features a different arrangement altogether, while Sodium hydroxide (NaOH) is cubic, with all axes equal. Thus, the only correct option that matches the orthorhombic classification is Barium sulfate.
Why the other options are wrong
- A. Lead chromate (PbCrO₄) crystallizes in the tetragonal crystal system, which is different from orthorhombic. This system is characterized by a square base and varying heights.
- C. Zinc oxide (ZnO) crystallizes in the hexagonal crystal system, featuring a six-sided symmetry. This structure is not orthorhombic, which makes it incorrect for this question.
- D. Sodium hydroxide (NaOH) crystallizes in the cubic crystal system. This system has equal axes and all angles equal to 90 degrees, differing from the orthorhombic arrangement.
Q141. Alkoxy carbonyl functional group is present in:
- A. Ether
- B. Aldehyde
- C. Carboxylic acid
- D. Ester✓
Explanation: The alkoxy carbonyl functional group is a defining feature of esters, which are characterized by the presence of a carbonyl group (C=O) bonded to an alkoxy group (–O–R). In this case, option D (Ester) is correct because it contains both components of the alkoxy carbonyl functional group. The other options do not fit the definition:Option A (Ether): Ethers lack the carbonyl group altogether and consist solely of an oxygen atom bonded to two hydrocarbon groups.Option B (Aldehyde): Aldehydes have a carbonyl group bonded to a hydrogen atom and do not have an alkoxy component.Option C (Carboxylic acid): While carboxylic acids contain a carbonyl, they also include a hydroxyl group, which is different from the alkoxy structure.Thus, the correct identification of the alkoxy carbonyl functional group is essential for recognizing that esters (option D) are the correct answer.
Why the other options are wrong
- A. An ether is characterized by an oxygen atom connected to two alkyl or aryl groups. It does not contain a carbonyl group, so it cannot be classified as having an alkoxy carbonyl functional group.
- B. An aldehyde features a carbonyl group (C=O) directly attached to a hydrogen atom. While it does have a carbonyl, it lacks the alkoxy component, which is essential for the alkoxy carbonyl functional group.
- C. A carboxylic acid contains both a carbonyl and a hydroxyl group (–COOH). Although it has a carbonyl group, it does not feature the alkoxy part, which is necessary for identifying the alkoxy carbonyl functional group.
Q142. Equal forces F act on isolated bodies A and B. The mass of B is 1/5 times that of A. The magnitude of the acceleration of A is:
- A. 1/5 times that of B✓
- B. 1/3 times that of B
- C. The same as B
- D. nine times that of B
Explanation: According to Newton's second law, F = ma, where F is the force, m is the mass, and a is the acceleration. Since equal forces F act on both bodies A and B, we can express their accelerations as follows:For body A: a_A = F/m_AFor body B: a_B = F/m_BGiven that the mass of B (m_B) is 1/5 times that of A (m_A), we can substitute:m_B = (1/5)m_ATherefore, the acceleration of B becomes: a_B = F/(1/5)m_A = 5F/m_ANow, we know that:a_A = F/m_AThus, by comparing the two accelerations, we find:a_A = (1/5) * a_BThis means that the magnitude of acceleration of A is indeed 1/5 times that of B.Options B, C, and D are incorrect because they either miscalculate the relationship between the accelerations based on the mass ratio or ignore the fundamental principle that acceleration is inversely proportional to mass when the same force is applied.
Why the other options are wrong
- B. This option incorrectly suggests that A's acceleration is a fraction of B's acceleration that is larger than 1/5. Given the mass relationship, this is not valid.
- C. This option is incorrect because it ignores the effect of mass on acceleration. A cannot have the same acceleration as B due to the difference in mass.
- D. This option is greatly exaggerated and incorrect. It fails to consider the ratio of the masses and the definition of acceleration.
Q143. A body is moved through a displacement of 15m towards the North, the total displacement will be zero when the body covered the same displacement towards:
- A. North
- B. South✓
- C. West
- D. East
Explanation: Displacement refers to the change in position of an object and is a vector quantity, meaning it has both magnitude and direction. In this question, the body initially moves 15m towards the North, resulting in a positive displacement of 15m in that direction. To achieve a total displacement of zero, the body must move back the same distance in the opposite direction. Therefore, moving 15m towards the South will cancel out the initial Northward displacement, resulting in a total displacement of zero.Options North, West, and East do not negate the initial displacement of 15m North, hence they do not result in zero total displacement.
Why the other options are wrong
- A. This option suggests moving in the same direction as the initial displacement. Thus, it does not lead to zero total displacement.
- C. Moving West does not negate the initial North displacement. Therefore, it does not result in zero total displacement.
- D. Similar to West, moving East does not cancel out the Northward displacement, leaving the total displacement non-zero.
Q144. When the range of a projectile is equal to one fourth of the height then which one is true:
- A. Tanθ=10
- B. Tanθ=12
- C. Tanθ=16✓
- D. Tanθ=1
Explanation: Since Rtan θ = 4H 1/4 H tan θ = 4H tan θ = 16
Why the other options are wrong
- A. Since Rtan θ = 4H 1/4 H tan θ = 4H tan θ = 16
- B. Since Rtan θ = 4H 1/4 H tan θ = 4H tan θ = 16
- D. Since Rtan θ = 4H 1/4 H tan θ = 4H tan θ = 16
Q145. The body is moving with with momentum of 100 kg m/s. What is the magnitude of force required to stop this body in 25 seconds?
- A. 4 N✓
- B. 25 N
- C. 100 N
- D. 2500 N
Explanation: The momentum of the body is given as 100 kg m/s, and the time taken to stop it is 25 seconds. To find the force required to stop the body, we can use the formula: Force = Change in Momentum / Time. Here, the change in momentum is equal to the initial momentum since the final momentum will be 0 when the body is stopped. Thus, Force = 100 kg m/s / 25 s = 4 N. This means that a constant force of 4 N is required to bring the body to rest in 25 seconds. The other options are incorrect because they either imply an unrealistic time frame for stopping the body or do not correspond to the given momentum and time constraints.
Why the other options are wrong
- B. This option is incorrect. It suggests that a force of 25 N is required, which would imply stopping the body in only 4 seconds (100 kg m/s / 25 N = 4 s), not 25 seconds.
- C. This option is incorrect. A force of 100 N would stop the body in just 1 second (100 kg m/s / 100 N = 1 s), which does not match the given time of 25 seconds.
- D. This option is incorrect. A force of 2500 N would stop the body in a fraction of a second (100 kg m/s / 2500 N = 0.04 s), which is far less than the required 25 seconds.
Q146. Doubling the initial velocity of a projectile while keeping all other parameters the same, the height reached by the projectile increases by:
- A. two times
- B. three times
- C. four times✓
- D. remains the same
Explanation: When a projectile is launched, the maximum height it reaches is directly related to the square of its initial vertical velocity. The formula for maximum height (H) is given by H = (v0y2)/(2g), where v0y is the initial vertical velocity and g is the acceleration due to gravity. When the initial velocity is doubled (v0y becomes 2v0y), the new height becomes H' = (2v0y)2/(2g) = 4(v0y2)/(2g) = 4H. Thus, the height increases by a factor of four. The other options (two times, three times, and remains the same) do not account for the quadratic relationship between velocity and height, which is why they are incorrect.
Why the other options are wrong
- A. This option suggests that the height doubles with the initial velocity. However, the height is proportional to the square of the velocity, not the linear value. Hence, this option is incorrect.
- B. This option indicates that the height increases by a factor of three. Like the previous option, it fails to recognize that the height is related to the square of the initial velocity, making this option incorrect as well.
- D. This option suggests that the height does not change with varying initial velocity. This is incorrect, as the height is influenced by the initial velocity, specifically its square.
Q147. The effect of air resistance, how long a stone takes to drop off a 125m high building, landing on the ground, take g=10m/s2:
- A. 3 sec
- B. 4 sec
- C. 18 sec
- D. 5 sec✓
Explanation: To determine the time it takes for a stone to drop from a height of 125 meters, we can use the formula for free fall:t = √(2h/g)Where:t = time in secondsh = height in meters (125m)g = acceleration due to gravity (10m/s²)Substituting the values into the formula:t = √(2 * 125 / 10) = √(25) = 5 secondsThis means the stone will take 5 seconds to hit the ground. The other options are incorrect because:Option A (3 seconds) is too short for the height of 125m.Option B (4 seconds) also underestimates the time required for such a drop.Option C (18 seconds) miscalculates the fall time by a large margin, significantly exceeding the expected duration.Therefore, the correct answer is Option D: 5 sec.
Why the other options are wrong
- A. This option suggests a time that is too short for an object to fall from 125 meters under the influence of gravity.
- B. This option is also too short to account for the distance of 125 meters, considering the acceleration due to gravity.
- C. This option greatly overestimates the time needed to fall 125 meters; it does not align with the physics of free fall.
Q148. The weight of a body is 120N and it is lifted to a height of 10m, work done on the body is:
- A. 120 J
- B. 100 J
- C. 1000 J
- D. 1200 J✓
Explanation: The work done on an object when it is lifted can be calculated using the formula: Work = Weight x Height. In this case, the weight of the body is 120N and it is lifted to a height of 10m. Plugging in the values:Work = 120N x 10m = 1200 J.Thus, the correct answer is 1200 J. The other options are incorrect because:120 J: This underestimates the work done as it does not use the correct height.100 J: This is significantly lower than the calculated work.1000 J: While closer, it still fails to multiply the weight and height correctly.Therefore, the correct answer is 1200 J.
Why the other options are wrong
- A. This option is incorrect because it does not account for the height the body is lifted. Work is calculated by multiplying weight by height.
- B. This option is incorrect as it significantly underestimates the work done. The correct calculation should yield a higher value based on the given weight and height.
- C. This option is also incorrect. While it is a larger value, it still does not reflect the correct multiplication of weight (120N) and height (10m).
Q149. A 200N force acts on 8 kg crate that starts from rest. At the instant the object has gone 2m, the rate at which the force is doing work is:
- A. 2.5 W
- B. 25 W
- C. 75 W
- D. 2000 W✓
Explanation: To find the rate at which the force is doing work (power), we first need to determine the velocity of the crate after it has moved 2 meters. Using Newton's second law, we can calculate the acceleration:F = ma200 N = 8 kg * aa = 25 m/s²Next, we use the kinematic equation to find the velocity after traveling 2m from rest:v² = u² + 2asv² = 0 + 2 * 25 m/s² * 2mv² = 100v = 10 m/sNow we can calculate the power using P = F * v:P = 200 N * 10 m/s = 2000 WThis explains why option D is correct. The other options are incorrect as they either miscalculate the power output or do not take into account the velocity of the crate after it has traveled the specified distance.
Why the other options are wrong
- A. This option is incorrect because it underestimates the power output given the force and the distance.
- B. This option is also incorrect as it does not take into account the velocity of the crate after moving 2m.
- C. This option miscalculates the power by not considering the correct velocity at the distance traveled.
Q150. Which of the following bodies has the largest kinetic energy?
- A. Mass 3M and speed v
- B. Mass 2M and speed 3v✓
- C. Mass 3M and speed 2v
- D. Mass M and speed 4V
Explanation: K.E = 1/2Mv2The K.E will be maximum when the product of "M" and "v²" is maximum. In (B) the product has maximum value i.e. 9Mv².
Why the other options are wrong
- A. Incorrect as per calculations.
- C. Incorrect as per calculations.
- D. Incorrect as per calculations.
Q151. A 2kg object is released from rest 8m above the surface of the Earth, During the fall work done against air resistance is 60J. Just before it hits the surface its speed is: (Hint-take g=10 m/sec2)
- A. 10 m/sec✓
- B. 36 m/sec
- C. 40 m/sec
- D. 45 m/sec
Explanation: To solve the problem, we first calculate the gravitational potential energy (PE) of the object when it is released from a height of 8 m. The formula for potential energy is PE = mgh, where m = 2 kg, g = 10 m/s², and h = 8 m. Thus, PE = 2 kg * 10 m/s² * 8 m = 160 J.Next, we account for the work done against air resistance, which is given as 60 J. The effective energy available for conversion into kinetic energy (KE) just before hitting the ground is PE - work done against air resistance = 160 J - 60 J = 100 J. Using the kinetic energy formula KE = (1/2)mv², we can rearrange it to find v: v = sqrt((2 * KE) / m) = sqrt((2 * 100 J) / 2 kg) = sqrt(100) = 10 m/s.Thus, the final speed of the object just before it hits the ground is 10 m/sec. The other options (36 m/s, 40 m/s, and 45 m/s) do not correctly account for the work done against air resistance, leading to incorrect calculations.
Why the other options are wrong
- B. This option is incorrect. It suggests a speed that is too high, likely resulting from a miscalculation of potential energy and work done against resistance.
- C. This option is incorrect. The speed calculated here does not consider the work done against air resistance, resulting in an overestimation of the final speed.
- D. This option is incorrect. It implies a final speed that exceeds the realistic limits based on the initial potential energy and work done against air resistance.
Q152. The speedometer of a car shows 36 km/hr. The angular speed of the wheels having 0.5m radius is:
- A. 5 rad/sec
- B. 10 rad/sec
- C. 15 rad/sec
- D. 20 rad/sec✓
Explanation: To solve for the angular speed of the wheels, we first need to convert the car's speed from kilometers per hour to meters per second. The car's speed is given as 36 km/hr, which can be converted to m/s by multiplying by a factor of (1000 m / 1 km) * (1 hr / 3600 s) = 10 m/s. Next, we apply the relationship between linear speed (v) and angular speed (ω) using the formula: ω = v / r, where r is the radius of the wheel. Given that the radius (r) is 0.5 m, we substitute the values into the formula: ω = 10 m/s / 0.5 m = 20 rad/sec. Thus, the correct answer is 20 rad/sec. The other options are incorrect because they do not accurately reflect the conversion and calculation based on the given data.
Why the other options are wrong
- A. This option is incorrect. To find the angular speed, you need to convert the linear speed from km/hr to m/s and then apply the formula ω = v/r. 5 rad/sec would indicate a much lower linear speed.
- B. This option is also incorrect. While it seems plausible, using the correct conversion and calculation reveals that this value does not match the expected angular speed for the given linear speed.
- C. This option is incorrect as well. Although it is closer to the correct answer, it does not reflect the accurate relationship between the linear speed of the car and the radius of the wheels.
Q153. The angular speed in radian/hour for the daily rotation of our earth is?
- A. π/12 radian/hour✓
- B. 12π radian/hour
- C. 24π radian/hour
- D. π/24 radian/hour
Explanation: The correct answer is π/12 radian/hour. To find the angular speed in radians, we recognize that one full rotation (2π radians) occurs in 24 hours. Thus, the angular speed can be calculated as:Angular speed = Total radians per rotation / Time in hours = 2π / 24 = π/12 radian/hour.
Why the other options are wrong
- B. This option proposes an angular speed of 12π radian/hour, which is incorrect, as it implies a rotation that would be impossibly fast for a daily cycle.
- C. This option indicates an angular speed of 24π radian/hour, which is also incorrect, as it suggests a rotation speed that far exceeds the actual speed of Earth's rotation.
- D. this option is incorrect, Earth rotates 2π radians in 24 hours.
Q154. A fly wheel rotates at constant speed of 600rpm. The angle described by the shaft in radians in one second is:
- A. 100
- B. 20π✓
- C. 0
- D. 20
Explanation: To determine the angle described by the shaft in radians in one second, we first need to convert the rotational speed from revolutions per minute (rpm) to radians per second. Since one revolution equals 2π radians, we can calculate:600 rpm = 600 revolutions/minute * (1 minute/60 seconds) * (2π radians/revolution) = 600 * (2π/60) = 20π radians/second.This calculation shows that the correct answer is 20π radians. Option A (100π) suggests an incorrect larger angle, while Option C (0) states no movement, which contradicts the rotating nature of the flywheel. Option D (20) misses the necessary π factor, making it incorrect as well.
Why the other options are wrong
- A. This option suggests a much larger angle than possible in one second given the constant speed. It's not feasible as it exceeds the rotational speed of the flywheel.
- C. This option implies that no angle is covered in one second, which is incorrect, as the flywheel is certainly rotating.
- D. This option does not take into account that the angle should be expressed in radians, specifically involving π. It misrepresents the angle by omitting the necessary π factor.
Q155. The angular speed of the second hand of a watch is:
- A. (∏/1800) rad/sec
- B. (∏/60) rad/sec
- C. (∏/30) rad/sec✓
- D. (2n) rad/sec
Explanation: The correct answer is (π/30) rad/sec. The second hand of a watch completes one full revolution (2π radians) in 60 seconds, which means its angular speed is calculated as: Angular Speed = Total Rotation / Time = (2π radians) / (60 seconds) = (π/30) rad/sec. Let's examine the other options: (π/1800) rad/sec suggests an extremely slow speed that is not applicable to a watch's second hand, as it would imply a highly unrealistic time for a full rotation. (π/60) rad/sec is also incorrect because it does not accurately represent the complete rotation in the given time frame of 60 seconds. (2n) rad/sec is completely irrelevant, as 'n' is not defined and does not pertain to the angular motion of the second hand.
Why the other options are wrong
- A. This option suggests that the second hand completes a rotation in 1800 seconds, which is incorrect. A watch second hand completes one full rotation in 60 seconds.
- B. This option indicates that the second hand completes a rotation in 60 seconds, which is partially correct. However, it does not accurately represent the angular speed in radians per second.
- D. This option is incorrect as it suggests an undefined variable 'n' which does not apply to the context of the second hand's angular speed.
Q156. A stretched string vibrates with frequency f, when tension in the string is T, for what value of tension, the frequency of the same string is doubled?
- A. 2T
- B. 4T✓
- C. 8T
- D. 16T
Explanation: The frequency of a stretched string is given by the formula f = (1/2L)√(T/μ), where T is the tension, L is the length of the string, and μ is the linear mass density. To double the frequency (2f), we set up the equation: 2f = (1/2L)√(T'/μ), where T' is the new tension. By squaring both sides and solving for T', we find that (2f)² = (1/2L)²(T'/μ). This leads to the conclusion that T' = 4T. Therefore, to double the frequency, the tension must be quadrupled. The other options are incorrect because:2T: Simply doubling the tension does not suffice to double the frequency, as frequency increases with the square root of tension.8T: Increasing to 8T would increase the frequency by a factor of 2.83, which is more than double.16T: Quadrupling the tension results in a frequency increase of 4 times, not just double.
Why the other options are wrong
- A. This option suggests that doubling the tension will double the frequency, which is incorrect. The frequency increases with the square root of tension, not linearly.
- C. This option implies that octupling the tension would double the frequency, which is incorrect as it would increase the frequency significantly more than doubling.
- D. This option suggests that increasing the tension to 16T would double the frequency, which is also incorrect. This would actually increase the frequency by a factor of 4, not 2.
Q157. The longitudinal waves travel more slowly in_ than in _
- A. solids, gas
- B. solids, liquids
- C. gases, solids✓
- D. liquid, gases
Explanation: Longitudinal waves, such as sound waves, travel slower in gases than in solids. This is because the particles in gases are more spread out, making it harder for the sound waves to transmit energy quickly. In contrast, solids have densely packed particles, allowing for faster energy transfer and wave propagation. Therefore, the correct answer is that longitudinal waves travel more slowly in gases than in solids. Option A is incorrect because it suggests that solids allow for slower wave travel compared to gases. Option B misrepresents the relationship between solids and liquids in terms of wave speed. Option D also incorrectly states that liquids allow for slower wave travel compared to gases. Hence, the only accurate statement is offered by Option C.
Why the other options are wrong
- A. This option suggests that longitudinal waves travel faster in solids than in gases, which is incorrect. Longitudinal waves actually travel faster in solids than in gases due to the closer particle arrangement in solids.
- B. This option implies that longitudinal waves travel slower in solids compared to liquids. This is not accurate as longitudinal waves typically travel faster in solids than in liquids due to greater density and elasticity in solids.
- D. This option states that longitudinal waves travel slower in liquids than in gases, which is incorrect. Waves travel faster in liquids than in gases due to the closer packing of particles in liquids.
Q158. Sinusoidal water waves are generated in a large ripple tank. The waves travel at 20 cm/s and their adjacent crests are 5.0 cm apart. The time required for each new whole cycle to be generated is:
- A. 100 s
- B. 2.0 s
- C. 4.0 s
- D. 0.25 s✓
Explanation: The time period (T) of a wave is calculated using the formula T = λ/v, where λ is the wavelength and v is the wave speed. Given that the wave speed is 20 cm/s and the distance between adjacent crests (wavelength) is 5.0 cm, the time period is calculated as T = 5.0 cm / 20 cm/s = 0.25 s. Therefore, the correct answer is 0.25 s. The other options are incorrect because they do not match the result of this calculation.
Why the other options are wrong
- A. This option is incorrect. The calculation for the time period using the wave speed formula does not result in this value.
- B. This option is incorrect. The time period is calculated using the wave speed and wavelength, and it should be much shorter.
- C. This option is incorrect. The time period should be calculated using the given wave speed and wavelength, leading to a smaller value.
Q159. The distance between adjacent node and anti-node is equal to:
- A. 𝛌
- B. 𝛌/2
- C. 2𝛌
- D. 𝛌/4✓
Explanation: The correct answer is 𝛌/4 because in wave motion, a node is a point of destructive interference where the amplitude is zero, and an anti-node is a point of constructive interference where the amplitude is maximum. The distance between a node and its adjacent anti-node is one quarter of the wavelength (𝛌), as the wave oscillates between these two points in its cycle. The other options are incorrect because they either represent the full wavelength (𝛌), half the wavelength (𝛌/2), or double the wavelength (2𝛌), which do not accurately describe the specific distance between a node and its adjacent anti-node.
Why the other options are wrong
- A. This option represents the full wavelength, which is the distance between two consecutive nodes or anti-nodes, not the distance between an adjacent node and anti-node.
- B. This option indicates half of the wavelength, which is the distance between two nodes or two anti-nodes, but not between an adjacent node and anti-node.
- C. This option signifies double the wavelength, which clearly exceeds the distance between adjacent nodes or anti-nodes and is incorrect.
Q160. A string clamped at its both ends, vibrates in four segments (loops). The length of string is 150cm. The wavelength of the wave is:
- A. 33.3 cm
- B. 66.7 cm
- C. 150 cm
- D. 75 cm✓
Explanation: The length of the string is 150 cm and it vibrates in four segments. Each segment corresponds to half a wavelength, so the total length of the string represents two wavelengths. Therefore, the wavelength can be calculated using the formula:wavelength = (length of string) / (number of segments / 2)Substituting the given values, we get:wavelength = 150 cm / (4 / 2) = 150 cm / 2 = 75 cm
Why the other options are wrong
- A. This option is incorrect because it implies a wavelength that does not fit the relationship between the length of the string and the number of segments formed.
- B. This option is also incorrect. A wavelength of 66.7 cm does not correspond correctly to the four segments of vibration on a 150 cm string.
- C. This option is incorrect as it suggests that the wavelength is equal to the length of the string, which is not the case for a string vibrating in segments.
Q161. The square root of the ratio of elasticity to mass density is equal to:
- A. Force
- B. Product of frequency and wavelength✓
- C. Co-efficient of viscosity
- D. Refractive index
Explanation: The correct answer is the product of frequency and wavelength. This relationship arises from the wave equation, where the speed of sound in a medium is given by the square root of the ratio of the elastic modulus (elasticity) to the mass density. Therefore, the square root of this ratio yields the speed of sound, which directly relates to how waves propagate through solids.Option A, Force, is incorrect because force is not a derived quantity from elasticity and mass density in this context. Option C, Co-efficient of viscosity, pertains to fluid dynamics and is unrelated to the elastic properties of solids. Lastly, Option D, Refractive index, is a concept in optics and does not apply to the relationship expressed in the question.
Why the other options are wrong
- A. Force is a physical quantity that causes an object to accelerate, but it does not directly relate to the ratio of elasticity to mass density in this context.
- C. The coefficient of viscosity measures a fluid's resistance to flow and does not relate to the properties defined by elasticity and density in solids.
- D. The refractive index is a measure of how much light bends when entering a medium but does not relate to elasticity or mass density in solids.
Q162. If the pressure of air enclosed in a long tube is increased 10 times, then the speed of sound will:
- A. Increase
- B. Decrease
- C. Remain constant✓
- D. Becomes zero
Explanation: The speed of sound in a gas is primarily determined by the temperature of the gas rather than the pressure. While increasing the pressure of air might intuitively suggest a change in sound speed, it is important to note that in ideal gas conditions, the speed of sound remains constant if the temperature does not change. Thus, in this scenario, the speed of sound will remain constant. Option A is incorrect because increasing pressure does not necessarily increase sound speed in a constant temperature environment. Option B is also incorrect as sound speed does not decrease with increased pressure. Option D is incorrect since sound cannot become zero simply because of pressure changes.
Why the other options are wrong
- A. While it may seem intuitive that increasing pressure would increase the speed of sound, in an ideal gas, the speed of sound primarily depends on the temperature rather than pressure. Therefore, this option is incorrect.
- B. This option suggests that higher pressure would hinder sound propagation. However, sound speed does not decrease with increased pressure in a constant temperature environment, making this option incorrect.
- D. This option is not feasible in the context of sound propagation. Sound cannot become zero merely due to an increase in pressure, so this option is incorrect.
Q163. The expression, Cp - R is equal to:
- A. Cv✓
- B. R
- C. Cp - Cv
- D. R + Cv
Explanation: The correct answer is Cv, as it represents the specific heat at constant volume. The equation Cp - R = Cv is derived from the relationship between the specific heats of gases. Specifically, for an ideal gas, the specific heat at constant pressure (Cp) is always greater than the specific heat at constant volume (Cv) by the gas constant R. Thus, when we subtract R from Cp, we arrive at Cv. The other options are incorrect because:Option B (R) is not equal to Cp - R; R is a separate constant.Option C (Cp - Cv) is not equal to Cp - R; rather, Cp - Cv equals R, which is a different relationship.Option D (R + Cv) is also incorrect; it does not derive from the relationship we are examining.Understanding these relationships is crucial in thermodynamics, particularly when dealing with ideal gases.
Why the other options are wrong
- B. This option is incorrect. R is the gas constant and does not equal Cp - R. Instead, it is a separate constant used in the equations of state for ideal gases.
- C. This option is incorrect. While the difference Cp - Cv is a valid expression and equals R for ideal gases, it does not equate to Cp - R.
- D. This option is incorrect. R + Cv does not reflect the relationship defined by Cp - R. Instead, the correct relationship is Cp = Cv + R.
Q164. In a certain process, 200J of heat energy is supplied to a system and at the same time 50J of work is done by the system. The increase in the internal energy of the system is:
- A. 25 J
- B. 100 J
- C. 150 J✓
- D. 250 J
Explanation: The first law of thermodynamics states that the change in internal energy (ΔU) of a system is equal to the heat added to the system (Q) minus the work done by the system (W). In this case:ΔU = Q - WGiven that 200J of heat energy is supplied to the system (Q = 200J) and 50J of work is done by the system (W = 50J), we can substitute these values into the equation:ΔU = 200J - 50J = 150JThus, the increase in internal energy is 150J, making Option C the correct choice.Options A, B, and D are incorrect because they either misapply the first law of thermodynamics or ignore the work done by the system, leading to inaccurate calculations of internal energy change.
Why the other options are wrong
- A. This option is incorrect. It underestimates the increase in internal energy by ignoring the correct relationship between heat and work.
- B. This option is also incorrect. While it considers some heat energy, it fails to account for the work done by the system properly.
- D. This option is incorrect. It miscalculates the internal energy change by adding the heat energy supplied without accounting for the work done by the system.
Q165. Two charges of magnitude q1= 1𝜇C and q2 = 5𝜇C, are separated at a distance r = 1x10-3m apart, the ratio of the magnitude of the forces acting on them will be:
- A. 1:5
- B. 1:25
- C. 1:3
- D. 1:1✓
Explanation: The magnitude of force on both charges is same. Hence the ratio will be 1:1.
Why the other options are wrong
- A. The magnitude of force on both charges is same. Hence the ratio will be 1:1.
- B. The magnitude of force on both charges is same. Hence the ratio will be 1:1.
- C. The magnitude of force on both charges is same. Hence the ratio will be 1:1.
Q166. For 0.5 Siemens of conductance, resistance will be:
- A. 1 Ω
- B. 2 Ω✓
- C. 20 Ω
- D. 10 Ω
Explanation: The correct answer is 2 Ω. This is determined by applying the formula for resistance, which is the inverse of conductance. Given that conductance (G) is 0.5 Siemens, we calculate the resistance (R) as follows: R = 1/G = 1/0.5 = 2 Ω. Options A, C, and D are incorrect because they do not satisfy the relationship between resistance and conductance. Specifically, option A suggests a resistance of 1 Ω, which would indicate a conductance of 1 Siemens, option C indicates a significantly higher resistance that implies very low conductance, and option D suggests a resistance that would indicate a conductance of only 0.1 Siemens.
Why the other options are wrong
- A. This option is incorrect. If conductance is 0.5 Siemens, the resistance cannot be 1 Ω, since the relationship is R = 1/G.
- C. This option is incorrect. A resistance of 20 Ω would imply a conductance much lower than 0.5 Siemens, which contradicts the given information.
- D. This option is also incorrect. A resistance of 10 Ω would suggest a conductance of 0.1 Siemens, which does not align with the provided conductance of 0.5 Siemens.
Q167. 1 volt x 1 ampere is equal to:
- A. 1 coulomb
- B. 1 newton
- C. 1 watt✓
- D. 1 hp
Explanation: According to the formula for electrical power, Power (P) = Voltage (V) x Current (I). Hence, when you multiply 1 volt by 1 ampere, you get 1 watt. That's why option C is the correct answer. Option A (1 coulomb) is incorrect because coulombs measure electric charge, not power. Option B (1 newton) is also incorrect as newtons measure force and do not relate to electrical power. Lastly, Option D (1 hp) is incorrect because while it is a unit of power, it is much larger than 1 watt and does not represent the correct value derived from the given voltage and current.
Why the other options are wrong
- A. 1 coulomb represents the amount of charge, not the power. The relationship between voltage, current, and power is not directly defined by charge alone.
- B. 1 newton is a unit of force. Although it is a fundamental unit in physics, it does not relate to the concepts of voltage, current, or power.
- D. 1 horsepower (hp) is a unit of power that is equivalent to about 746 watts. While it is a unit of power, it is not equivalent to 1 volt x 1 ampere.
Q168. A wire of length l has resistivity 𝛒. If the wire Is divided in two halves, then resistivity of each halve is:
- A. 𝛒/2
- B. 𝛒✓
- C. 2𝛒
- D. 𝛒/3
Explanation: When a wire is cut into two equal halves, the resistivity (𝛒) of the material from which the wire is made remains unchanged. Resistivity is an intrinsic property that depends on the material itself and its temperature. Therefore, regardless of the length of the wire, each half retains the same resistivity as the original wire. Thus, the correct answer is 𝛒. Option A (𝛒/2) is incorrect because resistivity does not decrease with the length of the wire. Option C (2𝛒) mistakenly suggests that cutting the wire increases the resistivity, which is not the case. Option D (𝛒/3) similarly misrepresents the concept, as resistivity remains constant for a given material.
Why the other options are wrong
- A. This option suggests that when the wire is cut in half, the resistivity is halved. However, this is incorrect because resistivity is an intrinsic property of the material and does not change regardless of the length of the wire.
- C. This option incorrectly suggests that cutting the wire in half would double the resistivity. Resistivity does not increase with a decrease in length; it remains constant for a given material at a specific temperature.
- D. This option implies that the resistivity would reduce to a third when the wire is cut. This is incorrect as resistivity remains a material property and does not change with the physical dimensions of the wire.
Q169. In how many hours a 1000 watt AC will consume one unit of electricity?
- A. 0.5 hr
- B. 1 hr✓
- C. 1.5 hr
- D. 2 hr
Explanation: The power of the AC is given as 1000 watts, which is equivalent to 1 kilowatt. One unit of electricity is defined as 1 kilowatt-hour (kWh). Therefore, a 1000 watt device will consume one unit of electricity in one hour. To understand why the other options are incorrect: 0.5 hours would only consume 0.5 units, 1.5 hours would consume 1.5 units, and 2 hours would consume 2 units of electricity. Thus, the correct answer is 1 hour.
Why the other options are wrong
- A. This option suggests that the 1000 watt AC will consume one unit in just half an hour, which is incorrect since it would actually consume 0.5 units in that time.
- C. This option indicates that the AC will take 1.5 hours to consume one unit, which is incorrect as it would consume 1.5 units in that timeframe.
- D. This option suggests that it takes 2 hours to consume one unit, which is also incorrect since the AC would consume 2 units in that duration.
Q170. Of the following, the copper conductor that has the least resistance must be:
- A. Thick, short and cool✓
- B. Thin, long and hot
- C. Thick, long and hot
- D. Thin, short and cool
Explanation: The correct answer is Thick, short and cool because resistance is inversely related to the cross-sectional area and directly related to the length of the conductor. A thicker conductor (larger cross-sectional area) lowers resistance, while a shorter conductor reduces the path for current flow. Cool temperatures decrease the resistivity of copper, contributing to even lower resistance. In contrast, the options Thin, long and hot, Thick, long and hot, and Thin, short and cool do not meet all criteria for minimizing resistance. The first option suffers from both thinness and length, the second has increased length and temperature, and the last option, despite being short and cool, is thin which increases resistance.
Why the other options are wrong
- B. This option is incorrect because a thin conductor has a smaller cross-sectional area, which increases resistance. Additionally, being long increases resistance and being hot raises resistivity.
- C. This option is incorrect as the length of the conductor increases resistance, and being hot increases resistivity, despite the thickness being advantageous.
- D. This option is incorrect because while being short and cool are beneficial, the thinness of the conductor increases resistance due to the reduced cross-sectional area.
Q171. A certain X-ray tube requires a current of 5mA at a voltage of 60kv. The rate of energy dissipation (in watts) is:
- A. 560
- B. 300✓
- C. 200
- D. 800
Explanation: To calculate the rate of energy dissipation (power) in an X-ray tube, we use the formula P = IV, where P is the power in watts, I is the current in amperes, and V is the voltage in volts. In this case, the current is given as 5mA, which is equal to 0.005A (since 1A = 1000mA). The voltage is 60kV, which is equal to 60000V (since 1kV = 1000V).Now, substituting the values into the formula: P = 0.005A * 60000V = 300 Watts. Therefore, the correct answer is Option B: 300 watts.The other options are incorrect because:Option A (560): This value does not correspond to the correct calculation.Option C (200): This is too low for the given current and voltage.Option D (800): This is too high and does not match the calculated power.
Why the other options are wrong
- A. This option is incorrect because it miscalculates the power. To get 560 watts, the current or voltage would need to be higher than stated.
- C. This option is incorrect because it underestimates the power. A current of 5mA at 60kV should yield a higher power output than 200 watts.
- D. This option is incorrect as it overestimates the power. The calculation does not support a result of 800 watts with the given current and voltage.
Q172. Ampere.second is the unit of:
- A. Power
- B. Charge✓
- C. Potential Difference
- D. Current
Explanation: The correct answer is Charge because the unit ampere.second represents a coulomb, which is the standard unit of electric charge. According to the definition of a coulomb, it is the amount of electric charge transported by a constant current of one ampere in one second. In contrast, the options for Power (watts), Potential Difference (volts), and Current (amperes) are all different physical quantities with their own distinct units. Power relates to energy transfer, potential difference measures energy per charge, and current measures the flow of electric charge per unit time, but none of these relate directly to the unit of charge itself.
Why the other options are wrong
- A. Power is measured in watts (W), which is defined as joules per second (J/s). This is not related to the unit of charge.
- C. Potential difference is measured in volts (V), which is defined as joules per coulomb (J/C). This does not correspond to ampere.second.
- D. Current is measured in amperes (A). While the unit ampere involves the concept of charge, ampere.second specifically refers to the amount of charge, not current itself.
Q173. The magnitude of the magnetic flux through area A has exactly the same value at angles:
- A. 0° and 180°✓
- B. 90° and 180°
- C. 180° and 270°
- D. 270° and 360°
Explanation: The magnitude of magnetic flux (Φ) through a surface is given by the formula Φ = B·A·cos(θ), where B is the magnetic field strength, A is the area, and θ is the angle between the magnetic field and the normal to the surface. For angles of 0° and 180°, cos(0°) = 1 and cos(180°) = -1, indicating that the magnitude of the flux remains the same, although the direction is opposite.In contrast, at 90°, the flux becomes zero because the angle leads to cos(90°) = 0. Similarly, at 270°, the flux is also zero due to the same cosine factor. Thus, options B, C, and D are incorrect as they do not yield the same non-zero flux values as found at 0° and 180°.
Why the other options are wrong
- B. This option is incorrect because at 90°, the magnetic field is perpendicular to the area, resulting in zero magnetic flux. At 180°, there is a non-zero flux, thus they do not have the same value.
- C. This option is incorrect because while 180° has a specific flux value, 270° also results in a perpendicular alignment, leading to zero flux. Therefore, they do not share the same magnitude.
- D. This option is incorrect because both 270° and 360° yield zero magnetic flux. Although they are equal in value, they do not match the positive flux values found at 0° or 180°.
Q174. A hydrogen atom that has lost its electron is moving east in a region where the magnetic field is directed from south to north. It will be deflected:
- A. Up✓
- B. Down
- C. North
- D. South
Explanation: The hydrogen atom, which is effectively a proton in this context since it has lost its electron, is moving east in a magnetic field directed from south to north. To find the direction of the magnetic force acting on the proton, we can use the right-hand rule. For a positive charge like a proton, point your right thumb in the direction of the velocity (east), and your fingers in the direction of the magnetic field (north). The direction in which your palm pushes will indicate the direction of the magnetic force, which is upwards in this case. Therefore, the correct answer is up.Option B (down) is incorrect because the right-hand rule does not support this direction. Option C (north) is incorrect as the force does not act along the direction of the magnetic field but rather perpendicular to it. Option D (south) is also incorrect for the same reason; the magnetic force is not directed south based on the right-hand rule.
Why the other options are wrong
- B. This is incorrect. When using the right-hand rule, the magnetic force does not point downward; instead, it points in the opposite direction to what is suggested here.
- C. This is incorrect. The magnetic force on the charged particle does not act in the north direction. The right-hand rule indicates a different direction based on the given parameters.
- D. This is incorrect. The magnetic force does not act southward when applying the right-hand rule in this scenario.
Q175. When the magnetic force acts on a charged particle, change occurs in:
- A. Magnitude of velocity only
- B. Magnitude and direction of velocity
- C. Only the direction of velocity✓
- D. Neither direction nor magnitude of velocity
Explanation: The magnetic force acts on a charged particle moving in a magnetic field, which is given by the equation F = q(v × B), where F is the magnetic force, q is the charge, v is the velocity, and B is the magnetic field. The force is always perpendicular to both the velocity of the particle and the magnetic field, which results in a change in the particle's direction of motion but not its speed. Thus, the correct answer is that only the direction of velocity changes. Option A is incorrect because it suggests that only the magnitude changes, which is not the case. Option B incorrectly states that both magnitude and direction change, which also does not happen. Option D is incorrect because it ignores the directional change caused by the magnetic force.
Why the other options are wrong
- A. This option is incorrect because the magnetic force does not change the speed of the particle; it only changes its direction.
- B. This option is incorrect because the magnetic force does not affect the magnitude of the velocity; it only alters the direction of the particle's motion.
- D. This option is incorrect because the magnetic force does affect the direction of the charged particle's velocity, even though it does not change its magnitude.
Q176. A constant magnetic field of 5T is passing through a static conducting loop of area 0.8m2, the induced emf is
- A. 4 V
- B. 10 V
- C. Zero✓
- D. 32 V
Explanation: The induced EMF (electromotive force) in a conducting loop is determined by Faraday's law of electromagnetic induction, which states that an EMF is induced when there is a change in magnetic flux through the loop. In this scenario, we have a constant magnetic field of 5T and a static conducting loop with an area of 0.8m². Since the magnetic field strength does not change, the magnetic flux through the loop remains constant, leading to an induced EMF of zero. Therefore, Option C is correct. Options A (4 V), B (10 V), and D (32 V) all propose values for the induced EMF that imply a change in magnetic flux, which does not exist in this instance due to the constancy of the magnetic field.
Why the other options are wrong
- A. This option suggests a value for induced EMF, but does not account for the fact that the magnetic field is constant and there is no change in magnetic flux through the loop.
- B. This option also proposes a specific induced EMF value. However, it overlooks the principle that a constant magnetic field does not induce any EMF in a static loop.
- D. This option presents a high value for induced EMF, which is incorrect as it implies a significant change in magnetic flux that does not occur in this scenario.
Q177. Magnetic flux linked with the conducting loop "A" is increased at the rate of 15 weber/second per and another conducting loop "B" is decreased at the rate of 15 weber/second, the ,magnitude of induced emf of:
- A. Loop A will induce an EMF equal to that of Loop B.✓
- B. Loop A is smaller than Loop B.
- C. Loop B is smaller than Loop A.
- D. Both will have zero induced EMF.
Explanation: The induced EMF in a loop is directly proportional to the rate of change of magnetic flux through the loop, as described by Faraday's law of electromagnetic induction. In this case, Loop A is having its magnetic flux increased at a rate of 15 weber/second, while Loop B is having its magnetic flux decreased at the same rate of 15 weber/second. Therefore, both loops will experience an induced EMF of equal magnitude but opposite direction. This leads to the conclusion that Loop A will have an induced EMF equal to that of Loop B. Option B is incorrect because the size of the loops does not affect the induced EMF in this context. Option C is similarly incorrect for the same reason. Option D is incorrect because both loops are experiencing changes in magnetic flux, resulting in non-zero induced EMF.
Why the other options are wrong
- B. The size of the loops does not affect the induced EMF as long as the rate of change of magnetic flux is the same, making this statement irrelevant.
- C. Similar to Option B, the size of the loops does not determine the induced EMF since the rate of change of magnetic flux is identical in magnitude.
- D. This is incorrect because there is a non-zero rate of change of magnetic flux for both loops, leading to a non-zero induced EMF.
Q178. For induced emf to be produced in a coil, the magnetic flux linked with the coil must:
- A. Only decrease
- B. Only increase
- C. Be constant
- D. Be Changed✓
Explanation: According to Faraday's law of electromagnetic induction, induced emf is generated when there is a change in magnetic flux through a coil. This change can be an increase or decrease in the magnetic flux. Therefore, the correct answer is that the magnetic flux must be changed to induce emf. Options A and B are incorrect because, while they mention changes in flux, they limit the scope to only decreases or increases, respectively, which does not encompass all scenarios of change. Option C is incorrect as it states that the magnetic flux must be constant, which would result in no induced emf. Hence, only a change in magnetic flux (either increase or decrease) can lead to the production of induced emf.
Why the other options are wrong
- A. While a decrease in magnetic flux can induce emf, it is not the only condition required. Induced emf can also occur with increases or fluctuations in flux.
- B. Similar to option A, an increase alone does not guarantee induced emf. The key factor is any change in magnetic flux, whether increasing or decreasing.
- C. If the magnetic flux linked with the coil remains constant, no induced emf will be generated. Induction only occurs with changing magnetic flux.
Q179. For half wave rectification, the number of diode needed in a circuit is:
- A. 1✓
- B. 2
- C. 3
- D. 4
Explanation: Half-wave rectification allows only one half of the AC signal to pass through, which is achieved using a single diode. This diode conducts current only during one half of the AC cycle (either positive or negative), effectively blocking the other half. Therefore, only one diode is necessary to implement this process. The other options are incorrect because:Option B (2 diodes): This configuration is used for full-wave rectification, not half-wave.Option C (3 diodes): Three diodes are not applicable in standard rectification methods for half-wave.Option D (4 diodes): This is typical of a bridge rectifier setup, used for full-wave rectification, which is not relevant to the half-wave process.
Why the other options are wrong
- B. This option is incorrect. Two diodes are used in full-wave rectification, not half-wave rectification, as they are needed to alternate the current flow through both halves of the AC cycle.
- C. This option is incorrect. Three diodes are not required for half-wave rectification; one diode is sufficient to allow one half of the AC waveform to be utilized.
- D. This option is incorrect. Four diodes are typically used in a bridge rectifier setup for full-wave rectification, not in a half-wave rectification circuit.
Q180. The frequency of a light beam "A" is half of that of light beam "B". The ratio EA/Ea of photons energies is:(hint: where EA & Es are the respective energies of light Beam "A" & "B")
- A. 1/2✓
- B. 1/4
- C. 1
- D. 2
Explanation: The correct answer is 1/2. The energy of a photon can be calculated using the formula E = hf, where E is energy, h is Planck's constant, and f is frequency. If the frequency of light beam 'A' is half that of light beam 'B' (i.e., fA = 1/2 * fB), we can express the energies of the two beams as EA = h * fA and EB = h * fB. Substituting for fA gives us EA = h * (1/2 * fB) = (1/2) * h * fB = (1/2) * EB. Thus, the ratio EA/EB = (1/2) and is equal to 1/2. The other options are incorrect for the following reasons: - 1/4: This implies a larger difference in energy than the frequency relationship allows. - 1: This suggests equal energies, which contradicts the stated frequency relationship. - 2: This incorrectly suggests that beam 'A' has higher energy, which is not possible given its lower frequency.
Why the other options are wrong
- B. This option is incorrect because it suggests that the energy of beam 'A' is a quarter of beam 'B'. Since energy is directly proportional to frequency, and beam 'A' has half the frequency of beam 'B', this is not possible.
- C. This option is incorrect because it implies that the energies of both beams are equal. Given that beam 'A' has half the frequency of beam 'B', its energy must be less than that of beam 'B'.
- D. This option is incorrect as it suggests that the energy of beam 'A' is twice that of beam 'B'. Since beam 'A' has a lower frequency, it actually has lower energy, making this option incorrect.
Q181. The wavelength of light beam "A" is twice the wavelength of light beam "B" The energy of a photon in beam "A" is:
- A. Half the energy of a photon in beam B✓
- B. One-fourth the energy of a photon in beam B
- C. Equal to the energy of a photon in beam B
- D. Twice the energy of a photon in beam B
Explanation: Since energy is inversely proportional to wavelength, doubling the wavelength cuts the energy in half. So a photon in beam A has half the energy of a photon in beam B.
Why the other options are wrong
- B. This option is incorrect. If the wavelength becomes four times larger, then the photon energy becomes one-fourth. Energy drops in proportion to the increase in wavelength.
- C. This option is incorrect. If the wavelength is reduced to half, the photon energy becomes twice as large. So the photon in beam A would have twice the energy of a photon in beam B.
- D. This option is incorrect. A photon in beam A would carry twice the energy of a photon in beam B.
Q182. If frequency of light is greater than threshold frequency, then in photoelectric effect the number of electrons increases with an increase in _ of light :
- A. Frequency
- B. Kinetic energy
- C. Intensity✓
- D. Momentum
Explanation: In the photoelectric effect, when the frequency of light exceeds a certain threshold frequency, photons can eject electrons from a material. The number of electrons emitted is directly related to the intensity of the light. Intensity measures the number of photons hitting the surface per unit area per unit time; thus, a higher intensity means more photons are available to knock electrons loose. Therefore, increasing the intensity results in more electrons being emitted.Option A (Frequency) is incorrect because while frequency determines the energy of the emitted electrons, it does not influence the number of electrons emitted once the threshold is surpassed. Option B (Kinetic energy) is also incorrect as it relates to the energy of the emitted electrons, not their quantity. Option D (Momentum) does not apply in this context, as it does not affect the count of emitted electrons.
Why the other options are wrong
- A. While frequency is important in determining the energy of the emitted electrons, it does not affect the number of electrons emitted if the frequency is above the threshold.
- B. Kinetic energy of the emitted electrons increases with frequency, but it does not determine the number of electrons emitted when the frequency is above the threshold.
- D. Momentum is a property of moving objects but does not directly affect the number of electrons emitted in the photoelectric effect.
Q183. Shortest wavelength associated to Paschen series is:
- A. 𝜆=8/RH
- B. 𝜆=9/RH✓
- C. 𝜆=19/RH
- D. 𝜆=4/RH
Explanation: The Paschen series corresponds to electron transitions from higher energy levels down to the n=3 level. The shortest wavelength associated with this series occurs during the transition from n=4 to n=3, which can be calculated using the Rydberg formula. The correct formula for this transition is 𝜆=9/RH, where RH is the Rydberg constant. The other options are incorrect because they correspond to transitions that are not part of the Paschen series or suggest incorrect energy levels.
Why the other options are wrong
- A. This option incorrectly suggests a transition that does not correspond to the Paschen series. The correct formula for the shortest wavelength in the Paschen series should involve the transition from n=4 to n=3.
- C. This option is incorrect. It does not correspond to any transition in the Paschen series and suggests a higher energy level than necessary for the shortest wavelength.
- D. This option is incorrect as it suggests a transition from a level that does not correspond to the shortest wavelength in the Paschen series.
Q184. The ratio of longest wavelength to shortest of Lyman series is:
- A. R
- B. 4/3✓
- C. 3/4
- D. 4
Explanation: The explanation of this question is given below;Maximum wavelength/Minimum wavelength = 121.6 nm/91.2 nm = 1.333... So the ratio of the maximum wavelength to the minimum wavelength in the Lyman series is approximately 1.33 = 4/3
Why the other options are wrong
- A. This option is incorrect as explained below.
- C. This option is incorrect as explained below.
- D. This option is incorrect as explained below.
Q185. The half-life of a radioactive element is 100 days. How much quantity of the 88 g of such element will remain after 3 half-lives:
- A. 8g
- B. 10g
- C. 11g✓
- D. 44g
Explanation: To find the remaining amount of a radioactive element after a certain number of half-lives, you can use the formula: Remaining Quantity = Initial Quantity × (1/2)^(number of half-lives). Here, the initial quantity is 88g and the number of half-lives is 3. Therefore, Remaining Quantity = 88g × (1/2)^3 = 88g × (1/8) = 11g. Thus, after 3 half-lives, 11g of the element remains.Option A (8g) is incorrect because it suggests an even more significant decay than calculated. Option B (10g) underestimates the remaining amount after 3 half-lives. Option D (44g) incorrectly assumes only one half-life has occurred, which is not the case.
Why the other options are wrong
- A. This option suggests a significant reduction but miscalculates the decay process. After 3 half-lives, the remaining quantity should be higher than 8g.
- B. This option underestimates the amount remaining. The calculation of remaining substance after 3 half-lives does not support this value.
- D. This option incorrectly assumes that only one half-life has occurred. After 3 half-lives, the amount should be much lower than 44g.
Q186. Radioactive kcSr has a half-life of 30 years. What percent of a sample of kcSr will remain after 90 years?
- A. 0%
- B. 12.5%✓
- C. 50%
- D. 75%
Explanation: To solve the question, we first determine how many half-lives have passed in 90 years. Given the half-life of kcSr is 30 years, we calculate:90 years ÷ 30 years/half-life = 3 half-lives.After each half-life, the remaining percentage of the original sample is halved. Starting with 100%:After 1 half-life (30 years): 100% ÷ 2 = 50%After 2 half-lives (60 years): 50% ÷ 2 = 25%After 3 half-lives (90 years): 25% ÷ 2 = 12.5%Thus, 12.5% of the original kcSr sample remains after 90 years. The other options are incorrect because they represent amounts after fewer half-lives or assume complete decay.
Why the other options are wrong
- A. This option suggests that no kcSr remains after 90 years. However, given the half-life of 30 years, this is not correct, as some of the isotope will still be present.
- C. This option represents the amount remaining after one half-life (30 years). After 90 years, more decay would have occurred, making this option incorrect.
- D. This percentage would be the remaining amount after two half-lives (60 years). After 90 years, more decay has occurred, leading to a smaller remaining percentage.
Q187. At the end of 15 min, 1/32 of a sample of radioactive polonium remains. The corresponding half-life is:
- A. 0.469 min
- B. 32 min
- C. 15 min
- D. 3 min✓
Explanation: The correct answer is 3 minutes. To determine this, we first need to understand the relationship between the half-life and the remaining fraction of the radioactive substance. After each half-life, the amount of the sample halves. Therefore, we can calculate how many half-lives have occurred in 15 minutes by examining the fraction that remains:Starting with 1 (the whole sample), after one half-life (3 min), we have 1/2 remaining; after two half-lives (6 min), we have 1/4 remaining; after three half-lives (9 min), we have 1/8 remaining; after four half-lives (12 min), we have 1/16 remaining; and after five half-lives (15 min), we have 1/32 remaining. This shows that 5 half-lives have occurred in 15 minutes, confirming that the half-life is indeed 3 minutes.Other options are incorrect as they do not result in 1/32 remaining after 15 minutes. For example, with a half-life of 15 minutes, only half of the sample would remain after 15 minutes (1/2), and with a half-life of 32 minutes, it would take much longer to reach 1/32 of the original sample.
Why the other options are wrong
- A. This option is incorrect. A half-life of 0.469 minutes would imply that the sample decayed too quickly to match the observed fraction of 1/32 remaining after 15 minutes.
- B. This option is incorrect. A half-life of 32 minutes would mean that it would take far too long to reach 1/32 of the original amount in only 15 minutes.
- C. This option is incorrect. If the half-life were 15 minutes, then only half of the sample would remain after 15 minutes, not 1/32.
Q188. Two equal and opposite charges of 10 C are separated at a distance of 10 cm, the electric potential at mid-point between the charges is:
- A. 20 V
- B. 10 V
- C. 5 V
- D. 0 V✓
Explanation: At the midpoint between two equal and opposite charges, the electric potential contributions from each charge are equal in magnitude but opposite in sign. Therefore, they cancel each other out, resulting in a total electric potential of 0 V at that point. This is why the correct answer is 0 V. The other options suggest a non-zero potential, which does not consider the crucial fact that the charges are equal and opposite, leading to a complete cancellation of their effects at the midpoint.
Why the other options are wrong
- A. This option suggests that the potential is the sum of the potentials from both charges, which isn't correct since they cancel each other out at the midpoint.
- B. This option assumes a contribution from one charge without considering the opposing influence of the second charge at the midpoint. The potentials from equal and opposite charges cancel each other out.
- C. This option implies a partial contribution from one charge, but again neglects the cancellation effect of the opposite charge at the midpoint.
Q189. The force of repulsion between two alike charges is 10 N in vacuum. When a material of Ep= 2 is placed between them. New force will be:
- A. 20 N
- B. 15 N
- C. 10 N
- D. 5 N✓
Explanation: In this problem, we start with a repulsive force of 10 N between two like charges in a vacuum. When a dielectric material with an electric polarization factor of Ep= 2 is introduced, the force between the charges is reduced by this factor. The relationship governing this change is given by:F' = F / Ep,where F' is the new force, F is the original force (10 N), and Ep is the electric polarization factor (which is 2 in this case). Thus:F' = 10 N / 2 = 5 N.This shows that the force is halved due to the presence of the dielectric. The other options are incorrect as they either suggest an increase in force or no change at all, which contradicts the effect of the dielectric material on the electric forces between the charges.
Why the other options are wrong
- A. This option suggests an increase in force, which is incorrect as the dielectric material reduces the force between the charges.
- B. This option implies a minor reduction in force, but does not account for the full effect of the dielectric polarization factor.
- C. This option indicates no change in force, which is incorrect as the presence of the dielectric will reduce the force.
Q190. The slope-of the charge-time graph for a charging capacitor gives:
- A. Current✓
- B. Voltage
- C. Force
- D. Energy
Explanation: The correct answer is Current, as the slope of the charge-time graph indicates how quickly charge is flowing into the capacitor, which is defined as current (I = dq/dt). A steeper slope corresponds to a higher current, meaning more charge is accumulating over time. The other options do not represent this relationship: Voltage is related to the charge stored but not the rate of charge flow, Force is unrelated to charge and time, and Energy pertains to the work done to charge the capacitor rather than the rate of charge accumulation.
Why the other options are wrong
- B. Voltage is related to the charge stored in the capacitor, but does not directly represent the slope of the charge-time graph. It reflects the potential difference across the capacitor rather than the rate of charge accumulation.
- C. Force is not relevant in this context, as the question specifically pertains to charge and time. Force is not a measure that can be derived from the charge-time graph.
- D. Energy relates to the amount of work done to charge the capacitor, but it is not represented by the slope of the charge-time graph. The graph specifically indicates the rate of charge flow, which is current.
Q191. Two small charged objects attract each other with a force F when separated by a distance d. If the charge on each object is reduced to one-fourth of its original value and the distance between them is reduced to d/2 the force becomes:
- A. F/16
- B. F/8
- C. F/4✓
- D. F/2
Explanation: According to Coulomb's Law, the force F between two point charges is given by the formula: F = k * (q1 * q2) / d^2, where k is the electrostatic constant, q1 and q2 are the magnitudes of the charges, and d is the distance between them. In this scenario, the charges are reduced to one-fourth of their original values, so we can write this as:F' = k * ((q1/4) * (q2/4)) / (d/2)^2Now simplifying this gives:F' = k * (q1 * q2) / (16 * (d^2/4)) = k * (q1 * q2) / (4 * d^2)This means that the new force F' is F/4. Therefore, option C is correct. The other options miscalculate the force due to incorrect consideration of both charge reduction and distance reduction.
Why the other options are wrong
- A. This option is incorrect because reducing the charge to one-fourth and the distance to d/2 does not result in such a decrease in force. The calculation shows that the force will not be this low.
- B. This option is also incorrect. While it accounts for the reduction in charge, it underestimates the effect of halving the distance, which increases the force significantly.
- D. This option is incorrect. While it considers the change in distance, it fails to fully account for the reduction in charge, resulting in a force that is higher than it should be.
Q192. If both the plate area and the plate separation of a parallel-plate capacitor doubled, the capacitance is
- A. Doubled
- B. Halved
- C. Unchanged✓
- D. Triple
Explanation: The capacitance (C) of a parallel-plate capacitor is given by the formula C = (ε₀ * A) / d, where A is the area of the plates, d is the separation between the plates, and ε₀ is the permittivity of free space. When both the plate area (A) and the plate separation (d) are doubled, the new capacitance becomes C' = (ε₀ * (2A)) / (2d) = (ε₀ * A) / d = C. Thus, the capacitance remains unchanged.Option A is incorrect as it mistakenly assumes that only the area increase affects capacitance without accounting for the separation change. Option B incorrectly assumes that the increase in separation alone would reduce capacitance. Option D miscalculates the relationship entirely by suggesting an increase by a factor of three.
Why the other options are wrong
- A. This option suggests that capacitance increases with the area increase while not considering the effect of increased separation. However, both changes affect capacitance.
- B. This option implies that the capacitance would decrease due to increased separation, but it neglects the fact that the area has also doubled.
- D. This option incorrectly suggests a threefold increase in capacitance, which overlooks the balancing effect of increasing both area and separation.
Q193. A 20𝜇F capacitor is charged 200 V. Its stored energy is:
- A. 4000 J
- B. 4 J
- C. 0.4 J✓
- D. 2000 J
Explanation: The energy stored in a capacitor can be calculated using the formula E = 0.5 * C * V^2. Here, C is the capacitance in farads, and V is the voltage. Given that C = 20μF (which is 20 × 10^-6 F) and V = 200 V, we can substitute these values into the formula:E = 0.5 * (20 × 10^-6) * (200^2) = 0.5 * (20 × 10^-6) * 40000 = 0.5 * 0.8 = 0.4 J.Thus, the correct answer is 0.4 J. The other options are incorrect because they either vastly overestimate or underestimate the energy based on the formula and the given values.
Why the other options are wrong
- A. This option is incorrect because it suggests an unrealistically large amount of energy stored in a typical capacitor, likely resulting from incorrect calculations.
- B. This option is incorrect as it underestimates the energy stored based on the given capacitance and voltage values.
- D. This option is incorrect as it represents an exaggerated amount of energy that a 20𝜇F capacitor cannot realistically hold at 200 V.
Q194. The primary winding of a transformer has a 120 V AC supply. What is the value of secondary voltage if the turn ratio is 20.(Hints: turn ratio =N1/N0)
- A. 2400V✓
- B. 1200V
- C. 24000V
- D. 200 V
Explanation: The primary winding of the transformer has a voltage of 120 V and a turn ratio of 20. The formula to find the secondary voltage (V2) is V2 = V1 × (N2/N1), where N2/N1 is the turn ratio. Here, the turn ratio is 20, which indicates that for every 1 turn in the primary winding, there are 20 turns in the secondary winding. Thus, V2 = 120 V × 20 = 2400 V, making Option A the correct answer. The other options either miscalculate the voltage based on incorrect turn ratios or misunderstand the relationship between the primary and secondary voltages.
Why the other options are wrong
- B. This option is incorrect. If the turn ratio were 10, this would be the correct answer (120 V × 10 = 1200 V), but with a turn ratio of 20, the secondary voltage is higher.
- C. This option is also incorrect. This would imply a turn ratio of 200 (120 V × 200 = 24000 V), which is much higher than the given turn ratio of 20.
- D. This option is incorrect. This value is much lower than the primary voltage and doesn't take into account the turn ratio of 20. It suggests a turn ratio of 1.67 (120 V × 1.67 = 200 V), which is not applicable here.
Q195. Statements:Some teachers are students.All students are girls.No student is a boy.Condusions:I. Some teachers are boys.II. Same girls are teachers.IlI. Some girls are students.
- A. Only I follows
- B. Only I, II and III follow
- C. Only II follows
- D. Only II and III follow✓
Explanation: The correct answer is D: 'Only II and III follow.' To analyze the conclusions:- Conclusion I ('Some teachers are boys') cannot be true because it contradicts the third statement that 'No student is a boy.' Since some teachers are students, it implies that those teachers cannot be boys.- Conclusion II ('Some girls are teachers') is valid because we know that some teachers are students, and since all students are girls, it follows that some of those girls must be teachers.- Conclusion III ('Some girls are students') is also valid as it directly follows from the statement that all students are girls.Thus, the only valid conclusions are II and III, making option D the correct choice.
Why the other options are wrong
- A. This option is incorrect because the first conclusion states that 'Some teachers are boys,' which contradicts the statement that 'No student is a boy.'
- B. This option is incorrect because conclusion I is false. While II and III are valid, the inclusion of I makes this option incorrect.
- C. This option is incorrect because, while conclusion II is valid, it ignores conclusion III which is also true.
Q196. Complete the following series: KCD, LEF, MGH,_ OKL.
- A. NQM
- B. PJI
- C. NIJ✓
- D. NJI
Explanation: The series can be analyzed by examining the letters in each segment. For the second letter in each term, the pattern follows:K (11) → L (12) → M (13) → N (14) → O (15) indicates a +1 increment.C (3) → E (5) → G (7) → I (9) → K (11) shows a +2 increment.Following this pattern leads us to the next term, which would be NIJ. The other options do not fit these increments:NQM fails to establish the correct sequence.PJI deviates from the progression.NJI, while similar, does not maintain the required increments.Thus, the correct answer is NIJ.
Why the other options are wrong
- A. This option does not follow the identified patterns in the series, particularly in the second segment where each letter progresses by a consistent increment.
- B. This option fails to maintain the alphabetical sequence established in the previous terms, thus it does not fit with the logical progression of the series.
Q197. Read the following statements and decide about the arguments.Statement: Does Pakistan need so many plans for development?Arguments:_ I. Yes. Nothing can be achieved without proper planning.II. No. Too much time, money and energy is wasted on planning.
- A. Only I is true✓
- B. Only II is true
- C. Either I or II is true
- D. Neither I nor II is true
Explanation: Argument I states that proper planning is essential for achieving development objectives, which is a strong argument. It highlights the necessity of having a clear direction and allocation of resources, which is fundamental in any development program. On the other hand, argument II suggests that planning is a waste of resources, which is a flawed perspective. Effective planning not only helps in utilizing resources efficiently but also guides the implementation process. Therefore, the correct answer is that only argument I is valid. The other options are incorrect as they either misinterpret the necessity of planning or disregard the validity of argument I.
Why the other options are wrong
- B. This option is incorrect as argument II claims that planning wastes time, money, and energy. However, effective planning is crucial for achieving development goals, thus making this argument invalid.
- C. This option is incorrect because only argument I holds true. Argument II is not valid, as effective planning is essential for development.
- D. This option is also incorrect because argument I is valid. Planning is necessary for development, which means that at least one argument is true.
Q198. Methyl tetrachloride (MTC) is a chemical found in some pesticides, glues, and sealants. Exposure to MTC can cause people to develop asthma. In order to halve the nation's asthma rate, the government plans to ban all products containing MTC. The government's plan to halve the nation's asthma rate relies on which of the following assumptions?
- A. Exposure to MTC is responsible for no less than half of the nation's asthma cases.✓
- B. Products containing MTC are not necessary to the prosperity of the country's economy.
- C. Asthma has reached epidemic proportions.
- D. MTC products are helpful for asthma.
Explanation: The correct answer is Option A: 'Exposure to MTC is responsible for no less than half of the nation's asthma cases.' This is the underlying assumption of the government's plan, as it directly correlates the ban on MTC products with a significant reduction in asthma cases. Without this assumption, the effectiveness of such a ban in achieving the goal of halving asthma rates would be unfounded.Option B is incorrect because the economic implications of MTC products do not directly affect their relationship with asthma cases. Option C is not pertinent to the assumption needed for the plan, as the epidemic status of asthma does not imply that banning MTC will lead to a decrease in cases. Lastly, Option D is incorrect because it suggests a beneficial role for MTC products in asthma, which contradicts the rationale behind the proposed ban.
Why the other options are wrong
- B. This option is irrelevant to the assumption about asthma rates. The economic necessity of MTC products does not directly relate to their impact on asthma cases or the effectiveness of the ban in reducing asthma rates.
- C. While asthma's prevalence may be concerning, this statement does not support the assumption about the direct cause of asthma cases. The government's plan focuses on MTC exposure, not the overall prevalence of asthma.
- D. This option contradicts the premise of the question, as it suggests that MTC products have a beneficial effect on asthma, which would undermine the logic behind the ban.
Q199. Statements:I. The Importance of yoga and exercise is being realized by all sections of the societyII. There is an increasing awareness about health in the society particularly among middle ages group of people.
- A. Statement I is the cause and statement II is its effect.
- B. Statement II is the cause and statement I is its effect.✓
- C. Both the statements I and II are independent causes.
- D. Both the statements I and II are effects of independent causes.
Explanation: Statement II indicates an increasing awareness about health, particularly among the middle-aged group. This awareness leads to the realization of the importance of yoga and exercise across all sections of society, as stated in Statement I. Thus, Statement II serves as the cause, and Statement I is the effect. The other options incorrectly interpret the relationship between the statements; Option A reverses the cause-effect order, while Options C and D suggest independence, which contradicts the clear connection presented in the statements.
Why the other options are wrong
- A. This option suggests that the realization of yoga's importance led to the increase in health awareness. However, the statements indicate that the awareness comes first, making this option incorrect.
- C. This option implies that neither statement influences the other. However, the clear causal relationship present in the statements makes this option incorrect.
- D. This option suggests that both statements occur independently without influencing each other. However, the statements are connected through a cause-effect relationship, rendering this option incorrect.
Q200. The rates of interest on Post office recurring deposit accounts have been increased with effect from 1st March. This has been done to attract more deposits.Course of ActionI. Efforts should also be made to make the public aware about this increase in the rate of Interest.II. If the deposits don't increase in next six months, the rate of interest should be further Increased.
- A. Only conclusion I follows
- B. Only conclusion II follows
- C. Neither I nor II follows
- D. Both conclusions I and II follow✓
Explanation: The question presents a scenario where the interest rates on post office recurring deposit accounts have been increased to attract more deposits. Conclusion I advocates for public awareness of this increase, which is essential for informing potential depositors and encouraging them to invest. Conclusion II suggests that if deposits do not rise in the following six months, the interest rate should be increased further, allowing for a responsive strategy to enhance deposit attraction.Both conclusions are valid because they address different aspects of the same objective: to increase deposits. The first focuses on communication, while the second emphasizes evaluation and adjustment based on initial results. Therefore, the correct answer is that both conclusions follow.Option A is incorrect as it only considers the need for public awareness, ignoring the evaluation aspect. Option B wrongly prioritizes only the evaluation without acknowledging the need for awareness. Option C dismisses both actions, which is inaccurate given their relevance to the situation.
Why the other options are wrong
- A. This option suggests that only the first course of action, to make the public aware of the increased interest rates, is valid. However, it overlooks the importance of evaluating the effectiveness of this action over time, which is also addressed in the second conclusion.
- B. This option implies that only the second course of action regarding increasing the interest rate further if deposits do not increase is valid. However, it neglects the necessity of public awareness about the current interest rate increase, which is crucial for attracting deposits.
- C. This option suggests that neither course of action is valid. This is incorrect as both actions are logical steps to take in response to the interest rate increase aimed at attracting more deposits.
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