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Free Kpk Mdcat Mock — Solved Past Paper with Answers
All 180 MCQs from Free Kpk Mdcat Mock, solved with the correct answer highlighted and a full explanation for every question. This is a free MDCAT Other Regional past paper — no signup, no ads. Practise it interactively in timed mode, drill more with free MDCAT MCQs, or browse all Other Regional papers.
Attempt this paper interactively →Q1. In each of the following questions, four alternative sentences are given.Choose the CORRECT option.
- A. Norma had put the button unit besides her on the couch.
- B. Norma put an button unit besides her on the couch.
- C. Norma put the button unit besides hers on the couch.
- D. Norma put the button unit beside her on the couch.✓
Explanation: The phrase "beside her" is used in the sentence to indicate the location of the button unit in relation to Norma. "Beside" means next to or by the side of someone or something. In this case, it suggests that Norma placed the button unit in close proximity to herself, likely on the couch within reach. The phrase provides spatial information and helps to specify the position of the button unit in relation to Norma.
Why the other options are wrong
- A. This option is incorrect. The phrase "had put" is in the past perfect tense, indicating that putting the button unit had been completed before another action in the past. However, the preposition "besides" is not correct here. It's more commonly used to indicate proximity or location, as in "The book is besides my favorite coffee mug."
- B. This option is also incorrect. The use of "an" instead of "a" before the noun "button unit" is incorrect, as "button unit" starts with a consonant sound.
- C. This option is incorrect. The pronoun "hers" requires a possessive form ("her" or "herself") to make sense, but it's not used correctly here.
Q2. Each sentence below has a blank indicating that something has been omitted. Choose the word that best fits in with the meaning of the sentence as a whole.Though the apprentice was a highly proficient IT professional, he had little or no _ in designing educational software.
- A. Creativity✓
- B. Prospect
- C. Configuration
- D. Competition
Explanation: The word that best fits in the blank is "Creativity."So the sentence reads:"Though the apprentice was a highly proficient IT professional, he had little or no creativity designing educational software."
Why the other options are wrong
- B. ❌ Doesn’t fit. “Prospect” refers to future possibilities or chances—not something you "have" or "lack" in this context.
- C. ❌ Too technical. Configuration refers to setup or arrangement—doesn’t reflect a personal ability or skill.
- D. ❌ Irrelevant. "Competition" doesn’t relate to the context of skill or capability in designing software.
Q3. Each sentence below has a blank indicating that something has been omitted. Choose the word that best fits in with the meaning of the sentence as a whole.The foreman’s clemency, particularly in being candid, had its _, one of which was _workmanship.
- A. Damages ... intolerable
- B. Ambiguities ...superior
- C. Shortcomings ...shoddy✓
- D. Occurrences ...attractive
Explanation: The sentence can be completed with the following words:"Shortcomings" and "shoddy" So the completed sentence is:"The foreman’s clemency, particularly in being candid, had its shortcomings, one of which was shoddy workmanship."
Why the other options are wrong
- A. This option is incorrect.
- B. This option is incorrect.
- D. This option is incorrect.
Q4. Select the most suitable synonym for the given word:CAPACIOUS
- A. Ample✓
- B. Cramped
- C. Stagnant
- D. Dormant
Explanation: Capacious is synonymous to roomy, having a generous amount of space.
Why the other options are wrong
- B. B) Cramped: Meaning: Having limited space or room; confined.
- C. C) Stagnant:Meaning: Not flowing or moving; stale
- D. D) Dormant:Meaning: In a state of inactivity or suspension.
Q5. In the following question, four alternative sentences are given. Choose the CORRECT one.
- A. In my experience, the awakening of that clear judgemeent as to what the college is for, is not as difficult as is often supposed.
- B. In my experience, the awakening of a clear judgement as for what the college is for,is not as difficult as is often supposed.
- C. In my experience, the awakening of a clear judgement as to what the college is for, is not as difficult as is often supposed.✓
- D. In my experience, the awakening of a clear judgement as to what the college is for, is not as much as difficult as often supposed.
Explanation: The best way to solve this question is to read each option in your head and then decide which one sounds the best and fits in well.In Option A, the spelling of judgement is incorrect.In Option B, there is no space left after the comma which is the wrong punctuation.In Option D, as much as is unnecessary text and can be removed.
Why the other options are wrong
- A. Incorrect because "that clear judgment" is awkward; "a clear judgment" is more natural.Also, "judgemeent" is a misspelling of "judgment."
- B. Incorrect because "as for what the college is for" is grammatically incorrect; "as to what the college is for" is the correct phrase.
- D. Incorrect because "as much as difficult" is incorrect; it should be "as difficult as."
Q6. Fill in the blank: I'm now going to give you 10 _ tips for running a really successful website.
- A. Invaluable✓
- B. Valueless
- C. Unworthy
- D. Unprofitable
Explanation: Invaluable is defined as something extremely useful; indispensable. Since these tips will help create a successful website, they are extremely helpful and thus important, making them invaluable.
Why the other options are wrong
- B. This answer is incorrect as the tips provided for running a successful website are likely to be valuable and useful for website owners.
- C. This answer is incorrect as the tips provided for running a successful website are likely to be worthy of consideration for website owners looking to improve their website's performance.
- D. This answer is incorrect as the tips provided for running a successful website may not necessarily be focused on generating profits, but rather on improving the website's overall performance and user experience.
Q7. His bag was quite _ so I easily carried it to his room.
- A. Cheap
- B. Heavy
- C. Light✓
- D. Short
Explanation: As the sentence says, the bag was easy to carry; therefore, option C (i.e., light) fits here.
Why the other options are wrong
- A. The word cheap refers to something low in price. This is irrelevant to the sentence.
- B. Heavy means something of great weight, difficult to lift or move. Since the bag was easy to carry, option B heavy doesn't fit here.
- D. Short means brief, momentary, small, or little, so this doesn't fit the context of the sentence.
Q8. Demonstrate the control of tenses and sentence structure in the following sentence:I _ (eat) an apple.
- A. Eat
- B. Eaten
- C. Eating
- D. Ate✓
Explanation: ‘Eaten’ [Option B] and 'Eating' [Option C] require helping verbs before them [e.g. am/have]. As these assisting verbs to are not given in the sentence these options are eliminated.Option D: ‘ate’ is the past tense of ‘eat’ which is the most appropriate choice.
Why the other options are wrong
- A. This option is not grammatically correct because "I" is singular so the verb should be with "s".
- B. This option is not grammatically correct. There should be a helping verb with eaten.
- C. This option is not grammatically correct. Eating requires a helping verb.
Q9. Comprehend key vocabulary.This medicine is _ from plants.
- A. Deprived
- B. Derived✓
- C. Derisive
- D. Derivative
Explanation: “Derived” is correct because it means obtained or extracted from a source, which fits the sentence. “Deprived” means denied or robbed of something, which changes the meaning completely.
Why the other options are wrong
- A. “Deprived” is an adjective meaning lacking or denied something, so it doesn’t fit the context. Derived correctly shows the medicine comes from plants.
- C. “Derisive” means mocking or expressing contempt, which doesn’t fit the context of medicine being obtained from plants. “Derived” correctly conveys originating or obtained from a source.
- D. “Derivative” implies something copied or unoriginal. Here, “derived” correctly shows the medicine comes from plants, so “derivative” is wrong.
Q10. In which model do proteins float in membrane like icebergs in sea:
- A. Lock and key model
- B. Induced fit model
- C. Fluid mosaic model✓
- D. Lotka volterra model
- E. All of these
Explanation: As per the fluid mosaic model cell membranes have proteins as icebergs in a sea of lipids (lipid). Hence option C is correct.
Why the other options are wrong
- A. Option A is incorrect because the lock and key model is the model used to explain the mode of action of enzymes.
- B. Option B is incorrect because the induced fit model is another model used to explain the mode of action of enzymes, in which enzymes do not behave as rigid locks but can instead modify their shapes to ensure that they fit well around substrates.
- D. Option D is incorrect because the Lotka–Volterra model is a model that can theoretically predict the outcome of interspecific competition between two species.
- E. This option is incorrect.
Q11. Which of the following are not polymer?
- A. Proteins
- B. Polysaccharides
- C. Lipids✓
- D. Nucleic acids
Explanation: The correct answer is Lipids. Unlike proteins, polysaccharides, and nucleic acids, lipids do not consist of repeating monomer units and therefore are not classified as polymers. Proteins are polymers because they are made up of amino acids linked in chains. Polysaccharides are polymers of monosaccharides, and nucleic acids are polymers of nucleotides, each consisting of a series of repeated structural units.
Why the other options are wrong
- A. Proteins are formed by long chains of amino acids, which are their monomers. Hence, they are polymers.
- B. Polysaccharides consist of repeated units of monosaccharides, making them polymers.
- D. Nucleic acids are formed from long chains of nucleotides, their monomers, thus classifying them as polymers.
Q12. What are the components of a nucleotide?
- A. Purine, pyrimidine and phosphate
- B. Purine, sugar and phosphate
- C. Nitrogen base, sugar and phosphate✓
- D. Pyrimidine, sugar and phosphate
Explanation: The correct answer is Nitrogen base, sugar and phosphate.A nucleotide is the basic unit of DNA and RNA. It is made up of three components:A nitrogenous base: This is a ring-shaped molecule that contains nitrogen atoms. There are two types of nitrogenous bases: purines and pyrimidines. Purines are larger and have two rings, while pyrimidines are smaller and have one ring. The nitrogenous bases in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, the base uracil (U) takes the place of thymine.A pentose sugar: This is a five-carbon sugar molecule. In DNA, the sugar is deoxyribose. In RNA, the sugar is ribose.A phosphate group: This is a group of three oxygen atoms bonded to a phosphorus atom.The nitrogenous base is attached to the sugar molecule, and the phosphate group is attached to the other end of the sugar molecule. The nucleotides are linked together by the phosphate groups, forming a long chain.The sequence of nucleotides in DNA and RNA determines the genetic information of an organism.
Why the other options are wrong
- A. Purine, pyrimidine, and phosphate on their own don’t include a sugar. A sugar appears only when these components join to form a nucleoside or nucleotide.
- B. Purine, sugar and phosphate does not include all of the different types of nitrogenous bases found in DNA and RNA.
- D. Pyrimidine, sugar, and phosphate leave out the purine bases. This combination forms a nucleotide built around a pyrimidine only, so purines aren’t part of it.
Q13. A segment of DNA has 120 adenine and 120 cytosine bases. The total number of nucleotides present in the segment is:
- A. 120
- B. 240
- C. 60
- D. 480✓
Explanation: According to Chargaff's rule, in DNA, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of cytosine (C) is equal to the amount of guanine (G). This means that the number of adenine bases is equal to the number of thymine bases, and the number of cytosine bases is equal to the number of guanine bases.In the given segment of DNA, it is mentioned that there are 120 adenine (A) bases and 120 cytosine (C) bases. Since the number of A bases is equal to the number of T bases and the number of C bases is equal to the number of G bases, the total number of nucleotides can be calculated as follows:Number of nucleotides = Number of A bases + Number of T bases + Number of C bases + Number of G basesSince the number of A bases and T bases is equal, and the number of C bases and G bases is equal, we can calculate the total number of nucleotides as:Total number of nucleotides = 120 + 120 + 120 + 120 = 480Therefore, the total number of nucleotides present in the segment is 480.
Why the other options are wrong
- A. 120 nucleotides is the number of either adenine or cytosine bases. So, this option is not correct.
- B. 240 nucleotides is the number of adenine and cytosine bases together. So, this option is not correct.
- C. 60 nucleotides is the number of adenine bases alone. So, this option is not correct.
Q14. _ fats are solid at room temperature.
- A. Saturated✓
- B. Unsaturated
- C. All
- D. None
Explanation: Saturated fats are solid at room temperature because their molecular structure is straight and allows for tight packing, which is typical of animal fats. Unsaturated fats, however, have kinks in their structure that prevent them from packing tightly, causing them to be liquid at room temperature, which is typical of plant oils. Therefore, the correct answer is that saturated fats are solid at room temperature, distinguishing them from unsaturated fats.
Why the other options are wrong
- B. Unsaturated fats have one or more double bonds causing kinks in their structure, preventing tight packing. This results in them being liquid at room temperature, as seen in many plant oils.
- C. Not all fats are solid at room temperature; only saturated fats have this property. Unsaturated fats are usually liquid.
- D. This is incorrect as saturated fats are solid at room temperature, particularly animal fats.
Q15. A → B → C → D → EAccumulation of “E” will control the above pathway through:
- A. Feedback mechanism
- B. Feedback activation
- C. Positive feedback
- D. Feedback inhibition✓
Explanation: Feedback inhibition is a crucial regulatory mechanism in metabolic pathways where the accumulation of the end product 'E' inhibits an enzyme earlier in the pathway, usually the first enzyme, to prevent overproduction. This maintains balance and prevents resource wastage. Other options, such as 'feedback mechanism' and 'positive feedback', are either too general or describe different regulatory processes that do not directly apply to the scenario described in the question. 'Feedback activation' is not a recognized term in this context and inaccurately suggests activation rather than inhibition.
Why the other options are wrong
- A. A feedback mechanism is a broad term that encompasses both positive and negative feedback processes. In this context, it is too general and does not specifically refer to the inhibition of the pathway due to the accumulation of end products.
- B. Feedback activation is not a recognized term in the context of biochemical pathways. It inaccurately implies that the accumulation of 'E' would activate the pathway, which contradicts the usual regulatory mechanisms where accumulation usually leads to inhibition.
- C. Positive feedback amplifies changes and typically leads to an increase in the output or product. While important in some systems, it is uncommon in metabolic pathways where regulation is needed to prevent overproduction.
Q16. Which of these enzymes works best at a pH of 9.70?
- A. Arginase✓
- B. Pancreatic enzyme
- C. Catalase
- D. Chymotrypsin
Explanation: Arginase operates optimally at a pH of around 9.7. It is involved in the urea cycle, converting arginine into ornithine and urea.
Why the other options are wrong
- B. While pancreatic enzymes are essential for digestion, they generally function best at a pH range of approximately 8.0 to 9.0, which is slightly lower than the specified pH of 9.70.
- C. Catalase is an enzyme that helps break down hydrogen peroxide and has an optimal pH of about 7.6. Therefore, it is not well-suited for activity at a pH of 9.70.
- D. Chymotrypsin is a digestive enzyme that works best within a pH range of 7 to 8. This is considerably lower than the optimal pH of 9.70, which limits its activity in this context.
Q17. Which of the following cell organelles is responsible for extracting energy from carbohydrates to form ATP?
- A. Ribosome
- B. Chloroplast
- C. Mitochondrion✓
- D. Lysosome
Explanation: The mitochondrion is called the "powerhouse of the cell" because it breaks down carbohydrates through cellular respiration and produces ATP. Ribosomes make proteins, chloroplasts perform photosynthesis, and lysosomes carry out digestion, but ATP formation mainly occurs in mitochondria.
Why the other options are wrong
- A. Ribosomes are cellular structures that read messenger RNA (mRNA) and assemble amino acids into proteins. They can be free in the cytoplasm or attached to the rough endoplasmic reticulum, facilitating protein synthesis for different cellular needs.
- B. Chloroplasts in plant cells contain pigments like chlorophyll that capture sunlight. This energy is then used in photosynthesis to convert carbon dioxide and water into chemical energy stored in glucose.
- D. Lysosomes are organelles that contain digestive enzymes to break down waste materials, cellular debris, and foreign substances. They enable intracellular digestion, recycling components for reuse within the cell.
Q18. Microtubules are the constituents of:
- A. Centrioles, spindle fibres and chromatin
- B. Centrosome, nucleosome and centrioles
- C. Cilia, flagella and peroxisomes
- D. Spindle fibres, centrioles and cilia✓
Explanation: Spindle fibres, centrioles, and cilia all contain microtubules. Microtubules are crucial for their structure and function.
Why the other options are wrong
- A. Centrioles and spindle fibers are made of microtubules that help in cell division. In contrast, chromatin consists of DNA and proteins for genetic packaging and does not contain microtubules.
- B. Centrosomes and centrioles organize microtubules during cell division. Nucleosomes, however, are complexes of DNA wrapped around histone proteins and are involved in DNA packaging, not in microtubule formation.
- C. Cilia and flagella are made of microtubules, which provide structure and enable movement. Peroxisomes, on the other hand, are organelles that carry out metabolic reactions, such as breaking down fatty acids, and do not contain microtubules.
Q19. Sarcolemma is primarily made up of:
- A. Lipoprotein✓
- B. Glycolipids
- C. Glycoprotein
- D. Nucleoproteins
Explanation: The correct answer is lipoprotein. The sarcolemma, as the cell membrane of muscle cells, consists mainly of a lipid bilayer with embedded proteins, together forming lipoproteins. These components are essential for maintaining the integrity and function of the sarcolemma. Options B, C, and D are incorrect because they either refer to minor components or are unrelated to the structural makeup of the sarcolemma.
Why the other options are wrong
- B. Glycolipids are present in cell membranes but are not the primary component of the sarcolemma, which is dominated by lipids and proteins.
- C. While glycoproteins are important for cell-cell recognition and signaling, they are not the primary structural component of the sarcolemma.
- D. Nucleoproteins are associated with the nucleus and genetic material, not the primary structure of muscle cell membranes like the sarcolemma.
Q20. Sertoli cells are found in:
- A. Ovaries and secrete progesterone
- B. Adrenal cortex and secrete adrenaline
- C. Seminiferous tubules and provide nutrition to germ cells✓
- D. Pancreas and secrete cholecystokinin
Explanation: Sertoli cells are specialized cells found in the seminiferous tubules of the testes. They play a crucial role in supporting and nourishing the developing germ cells (sperm cells) during spermatogenesis, which is the process of sperm production. Sertoli cells provide physical support, produce essential proteins and growth factors, regulate hormone levels, and create a suitable microenvironment for the maturation of sperm cells.
Why the other options are wrong
- A. This option is incorrect. Sertoli cells are not found in the ovaries. Instead, the ovaries contain other types of cells, such as granulosa cells, which are involved in follicle development and estrogen production.
- B. This option is incorrect. Sertoli cells are not found in the adrenal cortex. Adrenal cortex cells, specifically the cells of the zona fasciculata, are responsible for producing cortisol, aldosterone, and other steroid hormones—not adrenaline (also known as epinephrine), which is primarily secreted by the adrenal medulla.
- D. This option is incorrect. Sertoli cells are not found in the pancreas. The pancreas contains other cell types, such as exocrine cells that produce digestive enzymes and endocrine cells, specifically the pancreatic islet cells, which secrete hormones such as insulin and glucagon.
Q21. When you hold your breath, which of the following gas changes in blood would first lead to the urge to breathe?
- A. Falling CO2 concentration
- B. Rising CO2 and falling O2 concentration
- C. Falling O2 concentration
- D. Rising CO2 concentration✓
Explanation: During breath-holding, the accumulation of CO in the blood is the primary factor that triggers the urge to breathe. This rise in CO concentration stimulates the respiratory center in the brain, prompting the body to resume breathing to expel excess CO and maintain homeostasis.
Why the other options are wrong
- A. A decrease in CO2 concentration is not the primary trigger for the urge to breathe when holding your breath. Lower CO2 levels, often resulting from hyperventilation, do not naturally occur during breath-holding and do not stimulate the urge to breathe.
- B. While both rising CO2 and falling O2 concentrations can occur during breath-holding, the primary stimulus for the urge to breathe is the increase in CO2 levels. A decrease in O2 plays a secondary role.
- C. A decrease in O2 concentration can lead to symptoms like shortness of breath, but it is not the main trigger for the urge to breathe during breath-holding. The rising CO2 concentration is the primary trigger.
Q22. Which of the following is derived from the Latin word venom which means poisonous?
- A. Bacteria
- B. Fungi
- C. Virus✓
- D. Malaria
Explanation: Option A: Bacteria are single-celled organisms that can cause disease. They are not derived from the Latin word venemus. The word bacteria comes from the Greek word bakterion, which means "small staff". Otion B: Fungi are multicellular organisms that can cause disease. They are not derived from the Latin word venemus. The word fungi comes from the Latin word fungus, which means "mushroom". Option C: The Latin word venume is the root of the English word venom, which is a poisonous substance produced by some animals, such as snakes, spiders, and scorpions. The Latin word virus also comes from venume, and it refers to a small, infectious agent that can cause disease. The word virus was first used in English in the 16th century. It was borrowed from the Latin word virus, which originally meant "poison" or "venom". The modern meaning of virus as a small, infectious agent was not established until the 20th century. Option D: Malaria is a disease caused by a parasite. The parasite is not derived from the Latin word venemus. The word malaria comes from the Italian word mala aria, which means "bad air".
Why the other options are wrong
- A. Bacteria are single-celled organisms that can cause disease. They are not derived from the Latin word venemus. The word bacteria comes from the Greek word bacterium, which means "small staff".
- B. Fungi are multicellular organisms that can cause disease. They are not derived from the Latin word venemus. The word fungi comes from the Latin word fungus, which means "mushroom".
- D. Malaria is a disease caused by a parasite. The parasite is not derived from the Latin word venemus. The word malaria comes from the Italian word mala aria, which means "bad air".
Q23. Avidin is a protein that:
- A. Binds specifically to biotin in egg white✓
- B. Binds egg white with egg albumin
- C. Binds both biotin and albumin
- D. This protein is not found in egg white
Explanation: Avidin is a glycoprotein present in egg white that binds specifically to biotin (vitamin B7) with high affinity. This binding prevents the absorption of biotin if raw egg whites are consumed excessively, potentially leading to biotin deficiency. Cooking the egg whites denatures avidin, reducing its binding capacity. Other options are incorrect because avidin does not bind to egg albumin, and it is indeed found in egg white.
Why the other options are wrong
- B. Avidin does not bind to egg albumin. Albumin is a major protein in egg white, but avidin specifically binds to biotin, not albumin.
- C. Avidin binds specifically and with high affinity to biotin, not to albumin. Hence, this statement is incorrect.
- D. This statement is incorrect as avidin is indeed found in egg white.
Q24. Cells that kill cells that display foreign motifs on their surface are:
- A. Platelets
- B. Cytotoxic T cells✓
- C. Antigens
- D. Red blood cell
Explanation: Cytotoxic T cells are a type of T lymphocyte that specifically targets and kills cells displaying foreign motifs on their surface. They play a crucial role in the immune response against infected or abnormal cells. Platelets, antigens, and red blood cells do not possess this specific function of directly killing cells with foreign motifs.
Why the other options are wrong
- A. Platelets are involved in blood clotting and do not directly target and kill cells displaying foreign motifs on their surface.
- C. Antigens are substances that trigger an immune response but do not directly kill cells displaying foreign motifs on their surface.
- D. Red blood cells carry oxygen and are not involved in directly targeting and killing cells displaying foreign motifs on their surface.
Q25. Amphibians are poikilotherm. Therefore, they use to hibernate in:
- A. Winter✓
- B. Summer
- C. Autumn
- D. Spring
Explanation: Option A is correct.Correct! Amphibians, as poikilothermic organisms, hibernate in winter when the environment gets too cold for them to regulate their body temperature and avoid the risk of death due to cold or freezing. The other options are incorrect because they do not align with the characteristic behavior of poikilothermic animals like amphibians.
Why the other options are wrong
- B. Amphibians, being poikilothermic organisms, do not hibernate in summer as it is not necessary for them to regulate their body temperature during this time.
- C. Amphibians, being poikilothermic organisms, do not hibernate in autumn as it is not the coldest season where they face the risk of death due to cold or freezing.
- D. Amphibians, being poikilothermic organisms, do not hibernate in spring as it is a season of warming temperatures, not cold enough to trigger hibernation.
Q26. Purkinje fibers are connected with the impulse conducting system of:
- A. Heart✓
- B. Brain
- C. Skin
- D. Nephron
Explanation: The correct answer is Option A: Heart. Purkinje fibers are a critical component of the heart's impulse conducting system. They rapidly transmit electrical impulses, which orchestrate the nearly simultaneous contraction of the ventricles, facilitating efficient blood circulation. In contrast, the brain relies on neurons for impulse transmission, the skin uses nerve endings for sensory signaling, and the nephron uses epithelial cells for its physiological processes.
Why the other options are wrong
- B. Incorrect. The brain's impulse conducting system is composed of neurons, not Purkinje fibers. These neurons are responsible for transmitting electrical signals within the brain and to the rest of the body.
- C. Incorrect. The skin's impulse conducting system consists of nerves that transmit sensory information to the brain, and it does not involve Purkinje fibers.
- D. Incorrect. The nephron's impulse conducting system involves epithelial cells for ion and water transport, with no role for Purkinje fibers.
Q27. Some marine fishes possess salt-excreting organs known as:
- A. Thyroid gland
- B. Pituitary gland
- C. Adrenal gland
- D. Rectal gland✓
Explanation: The correct answer is the rectal gland, which is a specialized salt-secreting organ found in cartilaginous fishes like sharks. This gland helps these marine fishes maintain salt balance in their bodies. The other options, including the thyroid, pituitary, and adrenal glands, are not involved in salt excretion in marine fishes.
Why the other options are wrong
- A. The thyroid gland regulates metabolism and is not involved in salt excretion in marine fishes.
- B. The pituitary gland secretes hormones but is not responsible for salt excretion in marine fishes.
- C. The adrenal gland helps regulate blood pressure and stress responses, but it is not the organ responsible for salt excretion in marine fishes.
Q28. Piriformis syndrome is associated with which of the following disorder:
- A. Arthritis
- B. Sciatica✓
- C. Spondylosis
- D. Disc slip
Explanation: Piriformis syndrome is a condition where the piriformis muscle in the buttocks compresses the sciatic nerve, leading to sciatica symptoms such as pain, numbness, and tingling in the lower limbs. While a slipped disc can also cause sciatica, piriformis syndrome is specifically related to muscle compression rather than disc issues. Arthritis and spondylosis, on the other hand, are primarily joint and spinal disorders that do not typically involve the piriformis muscle or cause sciatica directly.
Why the other options are wrong
- A. Arthritis is primarily a joint disorder characterized by inflammation, pain, and stiffness. It does not typically involve the sciatic nerve or piriformis muscle.
- C. Spondylosis is a degenerative condition affecting the spine, mainly due to aging. It does not specifically involve the piriformis muscle or cause sciatica directly.
- D. A slipped disc can cause sciatica, but it is not directly linked to piriformis syndrome, which specifically involves the piriformis muscle compressing the sciatic nerve.
Q29. Diphtheria vaccines are an example of:
- A. Inactivated vaccine
- B. Toxoid vaccine✓
- C. Subunit vaccine
- D. Live, attenuated vaccine
Explanation: Toxoid vaccines, such as those for diphtheria and tetanus, contain inactivated toxins produced by bacteria. These vaccines do not target the bacteria but rather the harmful effects of the toxins they produce. Inactivated vaccines, however, use killed pathogens, primarily viruses, to elicit an immune response. Subunit vaccines use fragments of the pathogen, while live, attenuated vaccines use weakened forms of the whole virus or bacteria. The diphtheria vaccine specifically uses a toxoid to neutralize the effects of the toxin produced by the bacteria.
Why the other options are wrong
- A. Inactivated vaccines use a killed version of the germ that causes a disease. They are typically used against viruses like hepatitis A, influenza, polio, and rabies.
- C. Subunit vaccines use pieces of the germ—such as its protein, sugar, or capsid—to stimulate an immune response. They are used against diseases like Hepatitis B.
- D. Live, attenuated vaccines use a weakened form of the germ that causes a disease. They are used for diseases like measles, mumps, rubella, yellow fever, and typhoid.
Q30. DNA polymerase III works always in:
- A. 5 - 2' direction
- B. 5'- 3' direction✓
- C. 3'- 5 direction
- D. 2 - 5 direction
Explanation: DNA Polymerase III always works in the 5' to 3' direction.Explanation:DNA Polymerase III is the primary enzyme responsible for DNA replication in prokaryotes (such as E. coli).It adds nucleotides to the growing DNA strand only in the 5' to 3' direction because it can only add new nucleotides to the 3' end of the growing strand.This means:The leading strand is synthesized continuously in the 5' to 3' direction.The lagging strand is synthesized discontinuously in short fragments (Okazaki fragments) because replication must still proceed in the 5' to 3' direction.
Why the other options are wrong
- A. It is wrong as DNA polymerase can only make DNA in the 5’ to 3’ direction.
- C. It is wrong as DNA polymerase can only make DNA in the 5’ to 3’ direction.
- D. It is wrong as DNA polymerase can only make DNA in the 5’ to 3’ direction.
Q31. A heterozygote fruit fly has more florescent pigments in their eyes than a wild homozygote fruit fly, this is an example of:
- A. Co-dominance
- B. Incomplete dominance
- C. Over dominance✓
- D. Complete dominance
Explanation: When the phenotypic expression of heterozygotes becomes more intense than the homozygous state of the dominant allele, is called over-dominance. So, the above example is an example of Over dominance.
Why the other options are wrong
- A. In co-dominance, both alleles of a gene are equally expressed in the heterozygote, resulting in a phenotype that shows both traits simultaneously, such as the AB blood type where both A and B antigens are expressed.
- B. Incomplete dominance occurs when neither allele is completely dominant over the other, leading to a blended phenotype in heterozygotes, such as pink flowers resulting from a cross between red and white four o'clock plants.
- D. Complete dominance happens when one allele completely masks the effect of the other in a heterozygous condition, as seen in Mendelian inheritance where dominant traits are fully expressed.
Q32. Vomit centre is located in:
- A. Pons
- B. Midbrain
- C. Cerebellum
- D. Medulla✓
Explanation: The medulla oblongata is the posterior part of the brainstem and plays a key role in controlling autonomic functions and reflexes, such as vomiting. This is why the vomit center is located here. In contrast, the pons is more involved with sleep and respiratory rhythms, the midbrain with sensory information processing, and the cerebellum with motor control and balance. None of these has a direct role in the vomiting reflex.
Why the other options are wrong
- A. The pons is primarily involved in functions such as sleep and breathing regulation. It acts as a bridge between various parts of the brain but does not control vomiting.
- B. The midbrain is involved in processes related to vision, hearing, motor control, and alertness. It does not manage vomiting reflexes.
- C. The cerebellum is responsible for coordination and balance, ensuring smooth and precise movements. It is not associated with the vomiting reflex.
Q33. Which of the following is the suitable vector to be incorporated with the large external DNA fragment?
- A. Small size vector✓
- B. Large size vector
- C. Large size vector with no origin of replication
- D. Small size vector with no origin of replication
Explanation: In molecular cloning, a vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell, where it can be replicated and/or expressed. A vector containing foreign DNA is termed recombinant DNA. A small size is the suitable vector to be incorporated with the large external DNA fragment because it should be small in size so that it can easily integrate into the host cell. It should be capable of inserting a large segment of DNA. It should possess multiple cloning sites.
Why the other options are wrong
- B. Large-size vectors are DNA molecules with a greater capacity to carry larger DNA fragments. These vectors are more suitable for incorporating large external DNA fragments, as they can accommodate the additional genetic material.
- C. The origin of replication is a specific DNA sequence that is necessary for DNA replication to occur. It allows the vector to replicate itself within the host organism. If a large-size vector lacks an origin of replication, it will not be able to replicate and propagate within the host, making it unsuitable for use as a vector.
- D. Similarly to option (c), a small-size vector without an origin of replication will also be unsuitable for use as a vector because it cannot replicate and propagate within the host organism.
Q34. If black and white true breeding mice are mated and they result is all gray offspring, what inheritance pattern would this be indictive of ?
- A. Dominance
- B. Co dominance
- C. Multiple alleies
- D. Incomplete dominance✓
Explanation: Codominance means that no allele can block or mask the expression of the other allele. While incomplete dominance is a condition in which a dominant allele does not completely mask the effects of a recessive allele so the correct option is D as black and white parents produce gray offsprings
Why the other options are wrong
- A. In Genetics dominance means greater influence by one of a pair of genes (alleles) that affect the same inherited character. If an individual pea plant with the alleles T and t (T = tallness, t = shortness) is the same height as a TT individual, the T allele (and the trait of tallness) is said to be completely dominant.
- B. Codominance refers to a type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual.
- C. Multiple alleles can be defined as a series of forms of a gene situated at the same locus of homologous chromosomes. According to Mendel, each gene had two alternate forms that are either dominant or recessive.
Q35. Calcium ions bind with the troponin molecule and cause them to:
- A. Extend
- B. Change shape✓
- C. Contract
- D. Remain in the same position
Explanation: Upon binding with calcium ions, the troponin molecule undergoes a conformational change, which shifts the position of tropomyosin on the actin filament. This movement uncovers the myosin binding sites on the actin, allowing the myosin heads to attach and initiate muscle contraction. Option B is correct because it describes this process accurately.Option A is incorrect as troponin does not extend.Option C is incorrect because troponin does not contract; it facilitates contraction.Option D is incorrect since troponin changes position upon calcium binding.
Why the other options are wrong
- A. Incorrect. Troponin does not extend. Its role is to change shape when bound by calcium ions to facilitate muscle contraction.
- C. Incorrect. Troponin itself does not contract. It changes shape to expose the actin filament's myosin binding sites, which is essential for muscle contraction.
- D. Incorrect. Calcium binding causes troponin to change shape and shift its position, allowing the exposure of myosin binding sites on actin.
Q36. All of the following protect the body against entrance of germs except:
- A. Mucus membrane
- B. WBCs
- C. Ciliated cells
- D. RBCs✓
Explanation: RBCs have no role in immunity. RBCs (red blood cells) do not protect the body against the entrance of germs. RBCs are responsible for carrying oxygen to the tissues and carbon dioxide away from the tissues. They cannot engulf or kill germs.
Why the other options are wrong
- A. Mucus membranes do help protect the body against the entrance of germs. They do this in a few ways:Mucus membranes trap germs and prevent them from entering the body. Mucus is a sticky substance that is produced by mucus membranes. It helps to trap germs and other particles that enter the body through the nose, mouth, and other openings. The mucus is then moved out of the body by the action of cilia, which are tiny hair-like structures that line the mucus membranes.Mucus membranes contain antimicrobial substances that kill germs. Mucus membranes also contain antimicrobial substances, such as lysozyme and immunoglobulin A (IgA), that help to kill germs. Lysozyme is an enzyme that breaks down the cell walls of bacteria, while IgA is an antibody that helps to bind to and neutralize bacteria.Mucus membranes produce white blood cells that fight infection. Mucus membranes also contain white blood cells, which are the body's first line of defense against infection. The white blood cells move to the site of infection and help to kill the germs.
- B. WBCs (white blood cells) do help protect the body against the entrance of germs. They do this in a few ways:WBCs patrol the body for foreign invaders. WBCs are constantly circulating in the blood and lymph fluid, looking for foreign invaders. When they find a germ, they attach to it and engulf it.WBCs produce antibodies that attack germs. Antibodies are proteins that bind to specific antigens, which are molecules found on the surface of germs. When an antibody binds to an antigen, it triggers a cascade of events that ultimately leads to the destruction of the germ.WBCs release chemicals that kill germs. WBCs release chemicals, such as defensins and cytokines, that can kill germs directly.
- C. Ciliated cells do help protect the body against the entrance of germs. They do this by moving mucus and trapped germs out of the body. Ciliated cells are found in the lining of the respiratory tract, including the nose, throat, and lungs. They have tiny hair-like projections called cilia that beat rhythmically to move mucus and trapped germs up and out of the airways. This process is called mucociliary clearance.
Q37. During muscle relaxation, the calcium ions are:
- A. Released from the sarcoplasmic reticulum into the sarcoplasm
- B. Transported back from the sarcoplasm into the sarcoplasmic reticulum✓
- C. Further released from the sarcoplasmic reticulum into the sarcoplasm
- D. Remain constant without any movement
Explanation: During muscle relaxation, calcium ions are actively transported back from the sarcoplasm into the sarcoplasmic reticulum, which decreases their concentration in the sarcoplasm. This process allows the muscle fibers to relax as the removal of calcium ions leads to the detachment of the myosin heads from the actin filaments. Option B is correct because it accurately describes this process. The other options incorrectly describe the movement or state of calcium ions during muscle relaxation.
Why the other options are wrong
- A. This option is incorrect. During muscle relaxation, calcium ions are not released into the sarcoplasm; they are instead removed from it.
- C. This option is incorrect. During relaxation, calcium ions are not further released into the sarcoplasm; they are reabsorbed into the sarcoplasmic reticulum.
- D. This option is incorrect. Calcium ion levels do not remain constant during muscle relaxation; they are actively transported back into the sarcoplasmic reticulum.
Q38. Which of the following is not part of the first line of defense?
- A. Sebum
- B. Perspiration
- C. Interferon✓
- D. Epidermis
Explanation: The first line of defense includes physical and chemical barriers like the skin (including the epidermis), sebum, and perspiration, which help prevent pathogens from entering the body. Sebum and perspiration are secretions that support these barriers. Interferon, however, is part of the second line of defense. It is a protein that aids in the immune response by inhibiting viral replication and activating immune cells. This distinction makes interferon not a component of the first line of defense.
Why the other options are wrong
- A. Sebum is an oily substance secreted by sebaceous glands in the skin, forming part of the physical barrier in the first line of defense.
- B. Perspiration, or sweat, helps to flush out pathogens from the skin surface, making it a component of the first line of defense.
- D. The epidermis is the outermost layer of the skin, serving as a physical barrier against pathogens, thus part of the first line of defense.
Q39. In which of the following the female workers are sterile?
- A. Ants
- B. Honeybee✓
- C. Baboon
- D. Parrots
Explanation: The worker bee and the queen bee are both female but only the queen bee can reproduce. All drones are male. Worker beans clean the hive, collecting Pollen and nectar to feed the colony and they take care of the offsprings. The drones only job is to mate with the queen with the queen
Why the other options are wrong
- A. Fertilised eggs become infertile female worker in ants.
- C. Baboons have a relatively long life span and sexual maturity occurs at age 4–6. Females naturally experience an interbirth interval of approximately one to three years.
- D. All birds reproduce by laying eggs. Eggs are produced inside the female and then deposited in a nest. Since both ants and Honeybees female workers are sterile Therefore Option D is right.
Q40. The usual position of the two centrioles in relation to each other is at right angle in:
- A. Higher plant cells
- B. Lower plant cells
- C. Animals cells
- D. Both (B) &(C)✓
Explanation: Only lower plant cells and animal cells have centrioles at right angle to each other so correct option is D
Why the other options are wrong
- A. Centrioles are absent in higher plants because Plant cells have spindle fibre outside the nuclear envelope so they do not need centriole during cell division.
- B. Animal cells and cells of some microscopic organisms and lower plants contain two centrioles that are at right angles to one another.
- C. Animal cells and cells of some microscopic organisms and lower plants contain two centrioles that are at right angles to one another.
Q41. Of 100 ml of arterial blood, oxygen provided to the tissues is:
- A. 2ml
- B. 3ml
- C. 4ml
- D. 5ml✓
Explanation: 6 mL of oxygen is delivered, at tissue level in normal conditions so option D is correct
Why the other options are wrong
- A. a) 2mlThis option suggests that 2ml of oxygen is provided to the tissues from 100ml of arterial blood. It means that the blood delivers only a small amount of oxygen to the tissues, which is not sufficient for the body's needs.
- B. b) 3mlThis option suggests that 3ml of oxygen is provided to the tissues from 100ml of arterial blood. It is a slightly higher value compared to the previous option, but it still indicates a low oxygen delivery to the tissues.
- C. c) 4mlThis option suggests that 4ml of oxygen is provided to the tissues from 100ml of arterial blood. This value indicates a moderate amount of oxygen delivery to the tissues, which is closer to the physiological requirements of the body.
Q42. Enzymes work by lowering the _ of the reactions they catalyse:
- A. Kinetic energy
- B. Activation energy✓
- C. Heat energy
- D. Potential energy
Explanation: Activation Energy is the minimum amount of energy that the reacting species must possess in order to undergo a specified reaction. Enzymes speed up reactions by lowering this energy and hence the reaction occurs faster by the virtue of more reactants being capable of initiating and taking part in the reaction due to the lowered energy threshold.Kinetic energy (KE) of an object is the energy that it possesses due to its motion. Heat energy is the result of the movement of tiny particles called atoms, molecules or ions in solids, liquids and gases.Potential energy is energy that is stored – or conserved - in an object or substance. This stored energy is based on the position, arrangement or state of the object or substance. You can think of it as energy that has the 'potential' to do work.
Why the other options are wrong
- A. Kinetic energy – Enzymes do not lower kinetic energy; they affect reaction rates by reducing activation energy.
- C. Heat energy – Enzymes do not lower heat energy; they function within specific temperature ranges.
- D. Potential energy – Enzymes do not affect the potential energy of molecules.
Q43. First stable compound during Calvin cycle is:
- A. 3-phosphoglycerate✓
- B. Glyceraldehyde 3 - phosphate
- C. 1, 3 bisphosphoglycerate
- D. Ribulose bisphosphate
Explanation: The first stable compound formed during the Calvin Cycle is 3-phosphoglycerate (3-PGA). The Calvin Cycle, also known as the light-independent reactions of photosynthesis, is a series of enzyme-catalyzed reactions that take place in the stroma of chloroplasts. The cycle begins with the process of carbon fixation, where carbon dioxide from the atmosphere is combined with a five-carbon sugar called ribulose-1,5-bisphosphate (RuBP) using the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO).
Why the other options are wrong
- B. Glyceraldehyde-3-phosphate (G3P) is formed in the reduction stage of the Calvin cycle through a two-step process that converts 3-phosphoglycerate (3-PGA) into G3P
- C. 1,3-bisphosphoglycerate is formed in the Calvin cycle when each molecule of 3-phosphoglycerate (3-PGA) is phosphorylated by ATP in the reduction phase. This conversion is catalyzed by the enzyme phosphoglycerate kinase, and the reaction uses one molecule of ATP to add a phosphate group to 3-PGA, producing 1,3-bisphosphoglycerate and ADP
- D. Ribulose bisphosphate (RuBP) is regenerated in the Calvin cycle through a multi-step process that uses five molecules of the three-carbon sugar glyceraldehyde-3-phosphate (G3P)
Q44. Which of the following is a copper containing protein in electron transport chain?
- A. Plastoquinone
- B. Cytochrome - C
- C. Plastocyanin✓
- D. Ferredoxin
Explanation: It serves as an electron transfer agent between the cytochrome complex which follows Photosystem II and the entry point to Photosystem I of the non-cyclic electron transfer process. The electron transport chain is a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH2 to molecular oxygen. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.
Why the other options are wrong
- A. Plastoquinone is not a copper-containing protein. It is a lipid-soluble electron carrier involved in the light-dependent reactions of photosynthesis, but it does not contain copper (Cu).Key Facts About PlastoquinoneFunction: Transfers electrons from Photosystem II (PSII) to the cytochrome b6f complex in the electron transport chain (ETC) of photosynthesis.Location: Embedded in the thylakoid membrane of chloroplasts.Nature: It is a quinone molecule, not a protein and does not contain copper.
- B. Cytochrome c is a heme-containing protein, but it does not contain copper (Cu). Instead, it contains iron (Fe) within a heme group and plays a role in cellular respiration rather than photosynthesis.
- D. Ferredoxin is an iron-sulfur (Fe-S) protein, not a copper (Cu)-containing protein.Ferredoxin in PhotosynthesisFunction: It is an electron carrier that transfers electrons from Photosystem I (PSI) to NADP⁺ reductase in the light-dependent reactions of photosynthesis.Metal Ion: Contains iron (Fe) in Fe-S clusters, not copper (Cu).Location: Found in the stroma of chloroplasts.
Q45. This theory says that “mitochondria and chloroplasts are, in effect, ancient bacteria which now live inside the larger cells”:
- A. Darwin’s theory of evolution
- B. Lamarckism
- C. Neo - darwinism
- D. Endosymbiont theory✓
Explanation: The endosymbiotic theory states that some of the organelles in today's eukaryotic cells were once prokaryotic microbes. They eventually lost their cell wall and much of their DNA because they were not of benefit within the host cell. Mitochondria and chloroplasts cannot grow outside their host cell. The illustration of the prokaryotic microbes penetrating into the now called eukaryotes is presented below:
Why the other options are wrong
- A. a) Darwin’s Theory of Evolution – Focuses on natural selection and the evolution of species over time, not organelle origins.
- B. b) Lamarckism – Suggests organisms evolve by acquiring traits in response to the environment, which is now largely discredited.
- C. c) Neo-Darwinism – Modern synthesis of Darwin’s evolution with genetics, but does not explain organelle evolution.
Q46. The complete, mature, and infectious virus particle is known as:
- A. Capsomere
- B. Genome
- C. Virion✓
- D. Capsid
Explanation: The correct answer is c. Virion. A virion is the complete, mature, and infectious virus particle, consisting of the viral genome (DNA or RNA) enclosed within a protective protein coat called the capsid. Unlike the genome or capsid alone, which are only parts of a virus, the virion represents the fully assembled unit capable of infecting host cells.
Why the other options are wrong
- A. A capsomere is only one protein unit of the capsid, while a virion is the whole infectious virus particle. So calling the entire virus a capsomere would be incorrect.
- B. The genome of a virus refers to its genetic material, either DNA or RNA. It carries the instructions for the virus to replicate and produce new virus particles. While the genome is a crucial part of a virus, it does not represent the complete, mature, and infectious virus particle.
- D. The capsid is the protein coat that surrounds the genetic material of a virus. While important for protecting the genome, the capsid alone does not constitute the entire infectious virus particle.
Q47. Regarding structure of the human heart, Chordae tendinae are present in:
- A. Atria
- B. Pulmonary valve
- C. Ventricles✓
- D. Aortic valve
Explanation: Chordae tendineae (or simply chordae) are fibrous cords or tendons that are present in the heart to anchor the atrioventricular (AV) valves (specifically, the tricuspid and bicuspid/mitral valves) to the papillary muscles located in the ventricles. This prevents the valves from inverting into the atria when the ventricles contract and helps in maintaining proper valve function. Therefore, the correct location for chordae tendineae is Ventricles
Why the other options are wrong
- A. It's incorrect, chordae tendineae are present in ventricles as an extension of papillary muscles.
- B. It's incorrect, chordae tendineae are present in ventricles as an extension of papillary muscles.
- D. It's incorrect, chordae tendineae are present in ventricles as an extension of papillary muscles.
Q48. Each air-sac consists of several microscopic single layered structures called:
- A. Bronchioles
- B. Windpipe
- C. Bronchi
- D. Alveoli✓
Explanation: Alveoli are tiny air sacs in your lungs that take up the oxygen you breathe in and keep your body going. Although they're microscopic, alveoli are the workhorses of your respiratory system. People have an average of 480 million alveoli in their lungs, located at the end of bronchial tubes.
Why the other options are wrong
- A. Bronchioles are air passages inside the lungs. They branch off like tree limbs from the bronchi —the two main air passages through which air flows from the trachea (windpipe) after being inhaled through the nose or mouth.
- B. The windpipe, or trachea, is a tube that transports inhaled air from the upper throat down into the lungs, allowing for respiration.
- C. The bronchi are the passageways that connect your windpipe to your lungs. You have two main bronchi in your right and left lungs that divide and branch off into smaller segments, like tree branches. At the end of your bronchi, the alveoli exchange oxygen and carbon dioxide.
Q49. A chemical component that is NOT found in all viruses is:
- A. Protein
- B. Lipids✓
- C. DNA
- D. RNA
Explanation: The correct answer is B "Lipids". Non-enveloped viruses do not have a "lipid" covering, but their effects on humans can be just as devastating. These “naked” viruses only need their protein-based capsid and host detector proteins to infect host cells. Also viruses have either DNA or RNA as it's genetic material.
Why the other options are wrong
- A. Protein is found in every type of virus.
- C. Either RNA or DNA is found in every type of virus.
- D. Either RNA or DNA is found in every type of virus.
Q50. Sperms are produced in:
- A. Urethra
- B. Sperm dust
- C. Pancreas
- D. Testes✓
Explanation: The testes are the male reproductive organs responsible for producing sperm through a process called spermatogenesis.
Why the other options are wrong
- A. The urethra is a duct that carries urine and semen out of the body but is not involved in the production of sperm.
- B. "Sperm dust" is not a recognized term or structure. It does not correspond to any anatomical or physiological component in the male reproductive system.
- C. The pancreas is an organ involved in the digestive system and secretes enzymes and hormones, but it does not produce sperm.
Q51. It is the length of myofibril from one Z-line to the next:
- A. Plasma membrane
- B. Sarcomere✓
- C. Sarcoplasm
- D. Sarcolemma
Explanation: The sarcomere is the length of a myofibril from one Z-line to the next and is the basic contractile unit within muscle cells. During muscle contraction, the sarcomeres shorten as the actin and myosin filaments slide past one another, bringing Z-lines closer together. The other options, such as the plasma membrane, sarcoplasm, and sarcolemma, refer to different components of the muscle cell that do not define this specific structural unit.
Why the other options are wrong
- A. Incorrect. The plasma membrane refers to the outer membrane of the cell, not the structure within the myofibril.
- C. Incorrect. The sarcoplasm refers to the cytoplasm of a muscle cell, which encompasses the components necessary for cellular metabolism, but not the contractile units.
- D. Incorrect. The sarcolemma is the membrane that surrounds the muscle cell, playing a role in conducting electrical signals, not in defining the contractile units.
Q52. Antibodies are manufactured in:
- A. T lymphocytes
- B. Platelets
- C. Red blood cells
- D. B lymphocytes✓
Explanation: Antibodies are manufactured in B lymphocytes. B lymphocytes are a type of white blood cell that are responsible for the body's humoral immune response. The humoral immune response is the part of the immune system that fights off infection by producing antibodies. Antibodies are proteins that bind to specific antigens, which are molecules found on the surface of foreign invaders. When an antibody binds to an antigen, it triggers a cascade of events that ultimately leads to the destruction of the foreign invader. B lymphocytes are produced in the bone marrow. When a B lymphocyte encounters an antigen for the first time, it becomes activated. The activated B lymphocyte then divides and produces a clone of cells that all produce the same antibody. These cells are called plasma cells. Plasma cells secrete antibodies into the blood and lymph fluid.
Why the other options are wrong
- A. No, antibodies are not manufactured in T lymphocytes. Antibodies are manufactured in B lymphocytes.T lymphocytes, also known as T cells, are another type of white blood cell that plays a key role in the body's immune system. T cells are responsible for helping the body to fight infection by killing infected cells and by helping B cells to produce antibodies.
- B. No, antibodies are not manufactured in platelets. Antibodies are proteins that are produced by B cells in the bone marrow. Platelets are small, disk-shaped cells that are involved in blood clotting. They do not produce antibodies.
- C. No, antibodies are not manufactured in red blood cells (RBCs). RBCs are the most abundant type of blood cell. They are responsible for carrying oxygen from the lungs to the tissues. RBCs do not have a nucleus and are therefore unable to produce proteins, including antibodies.
Q53. 50 secondary oocytes in females and 50 secondary spermatocytes in males give rise to:
- A. 100 ova and 100 sperms
- B. 50 ova and 200 sperms
- C. 200 ova and 50 sperms
- D. 50 ova and 100 sperms✓
Explanation: Spermatogenesis is the process of formation of spermatid (n) from spermatogonia(2n). The process goes as follows:-Spermatogonia(2n)⟶ Primary Spermatocyte(2n)⟶2 Secondary Spermatocyte(n)⟶4 Spermatid(n)Oogenesis is the production of an ovum from oogonia. The mechanism, in short, can be depicted as below:-Oogonia(2n)⟶ Primary Oocyte(2n)⟶ Secondary Oocyte(n)+ Polar Body(n)This meiosis I is an unequal division leading to the formation of a haploid ovum and a polar body. The first polar body is said to be atretic and does not divide further. However, the secondary oocyte completes its meiosis during fertilization to form an egg(n) and the second polar body(n).So, 50 secondary oocytes produce 50 ovum and 50 secondary spermatocytes produce 100 sperms.
Why the other options are wrong
- A. This is not accurate. Secondary oocytes in females generally produce one ovum each, and secondary spermatocytes in males produce four sperm cells each. Therefore, the numbers should not be equal.
- B. This is not accurate. Secondary spermatocytes typically produce four sperm cells each, so 50 secondary spermatocytes would yield 200 sperm cells. However, secondary oocytes usually produce one ovum each.
- C. This is not accurate. The number of ova is usually less than the number of sperm cells produced, as each secondary oocyte typically produces one ovum, while each secondary spermatocyte produces four sperm cells.
Q54. The genotypes of a husband and wife are IAIB and IAi. Among the blood types of their children, how many different genotypes and phenotypes are possible?
- A. 3 genotypes; 4 phenotypes
- B. 4 genotypes; 3 phenotypes✓
- C. 4 genotypes; 4 phenotypes
- D. 3 genotypes; 3 phenotypes
Explanation: The correct answer is that there are 4 genotypes and 3 phenotypes. The parents' genotypes are IAIB (father) and IAi (mother). The possible genotypes for their children are:IAIA - Blood group AIAi - Blood group AIAIB - Blood group ABIBi - Blood group BThese genotypes result in three phenotypes: Blood group A (from IAIA and IAi), Blood group B (from IBi), and Blood group AB (from IAIB). Options A, C, and D are incorrect because they either miscount the number of genotypes or phenotypes.
Why the other options are wrong
- A. This is incorrect. The possible genotypes are IAIA, IAi, IAIB, and IBi, leading to only 3 phenotypes: A, B, and AB.
- C. This is incorrect. Although there are four genotypes, they only result in three phenotypes because IAIA and IAi both express blood group A.
- D. This is incorrect. There are four possible genotypes, not three. The phenotypes are correctly identified as three: A, B, and AB.
Q55. The partial pressure of oxygen in the alveoli of the lungs is:
- A. Equal to that in the blood
- B. More than that in the blood✓
- C. Less than that in the blood
- D. Less than that of carbon dioxide.
Explanation: The partial pressure of oxygen in the alveoli is higher than in the blood, facilitating the diffusion of oxygen from the alveoli into the blood, where it can be transported by hemoglobin to tissues throughout the body.
Why the other options are wrong
- A. This option is incorrect. If the partial pressures were equal, there would be no net movement of oxygen from the alveoli to the blood. The alveoli must have a higher partial pressure to drive diffusion of oxygen into the bloodstream.
- C. This option is incorrect. If the partial pressure of oxygen in the alveoli were less than in the blood, oxygen would not move into the bloodstream as required for proper physiological function. The direction of diffusion relies on a higher concentration of oxygen in the alveoli.
- D. This option is incorrect. The partial pressure of oxygen in the alveoli is higher than that of carbon dioxide to ensure efficient oxygen uptake and carbon dioxide removal during respiration.
Q56. Which of the following properties of an amino acid is affected by a change in pH?
- A. Oxidation of amino acid
- B. Atomization of amino acids
- C. Reduction of amino acid
- D. Ionization of amino acids✓
Explanation: The ionization state of amino acids is directly affected by pH. Both acidic and basic groups in amino acids can gain or lose protons based on the pH, altering their charge and affecting interactions with other molecules.
Why the other options are wrong
- A. Oxidation refers to the loss of electrons and is primarily influenced by redox conditions rather than pH. While pH can indirectly affect the reactivity of amino acids, oxidation itself is not directly altered by changes in pH.
- B. Atomization involves breaking a molecule down into its constituent atoms, which is a physical process unaffected by pH. This process does not involve changes in the ionization state of functional groups within the amino acids.
- C. Reduction involves the gain of electrons and is not directly influenced by pH changes. While pH can affect the overall ionization state of amino acids, reduction pertains more to electron transfer mechanisms rather than the acid-base properties affected by pH.
Q57. The Lock and Key Model for enzyme action proposed by Emil Fischer suggests that:
- A. Enzymes are unbiased for the substrate.
- B. Enzymes can modify their active sites.
- C. Enzymes are restricted to one reaction type.✓
- D. An enzyme can catalyze a variety of reactions.
Explanation: Emil Fischer (1890) proposed a Lock and Key model to visualize substrate and enzyme interaction. According to this model, as one specific key can open only a specific lock, in the same manner, a specific enzyme can transform only one substrate into products(s). According to the Lock and Key Model, the active site is a rigid structure. There is no modification or flexibility in the active site before, during, or after the enzyme action, and it is used only as a template. Later studies did not support this model in all reactions.
Why the other options are wrong
- A. The Lock and Key model suggests that enzymes are highly specific to their substrates, much like a specific key fits only a specific lock.
- B. This is incorrect. The Lock and Key model posits that the active site of the enzyme is a rigid structure that does not change. This idea contrasts with the later Induced Fit model.
- D. The Lock and Key model argues against this because it emphasizes the specificity of enzyme-substrate interactions, with each enzyme catalyzing only one type of reaction.
Q58. The transport of secretory proteins takes place through organelles in which of the following order?
- A. RER-Golgi apparatus-Secretory vesicles
- B. SER-RER-Golgi apparatus-Secretory vesicles
- C. RER-SER-Golgi apparatus-Secretory vesicles✓
- D. RER-Golgi apparatus-Secretory vesicles-SER
Explanation: The correct answer is C: RER-SER-Golgi apparatus-Secretory vesicles. This sequence accurately represents the pathway of secretory proteins. Initially, proteins are synthesized in the rough endoplasmic reticulum (RER), where ribosomes translate mRNA into polypeptide chains. These proteins then move to the smooth endoplasmic reticulum (SER) for further folding and modifications. Next, they are transported to the Golgi apparatus, where they undergo further processing, sorting, and packaging into secretory vesicles for transport out of the cell. Options A, B, and D are incorrect due to their flawed sequence of organelles. Option A misses the SER step, while Option B incorrectly starts with the SER instead of the RER. Option D places the SER at the end of the sequence, which is not where it functions in the transport process.
Why the other options are wrong
- A. This option outlines a sequence where proteins move from the rough endoplasmic reticulum (RER) to the Golgi apparatus and then to secretory vesicles. While it accurately reflects part of the transport process, it omits the essential step of moving proteins through the smooth endoplasmic reticulum (SER) for further processing, rendering it incomplete.
- B. This option incorrectly begins with the smooth endoplasmic reticulum (SER) before the rough endoplasmic reticulum (RER). In the synthesis of secretory proteins, the process starts in the RER, making this option fundamentally flawed.
- D. This option suggests an incorrect order by placing the smooth endoplasmic reticulum (SER) last. The SER is involved in processing before proteins reach the Golgi apparatus, making this sequence inaccurate.
Q59. Which of the following organelles is responsible for the production of steroid hormones?
- A. Lysosomes
- B. Golgi bodies
- C. Smooth endoplasmic reticulum✓
- D. Rough endoplasmic reticulum
Explanation: The smooth endoplasmic reticulum (SER) is crucial for the synthesis of steroid hormones, as it harbors enzymes necessary for the production of cholesterol and its conversion into various steroid hormones. This function is distinct from that of other organelles: lysosomes are involved in the degradation of cellular debris, the Golgi apparatus modifies and packages proteins and lipids, and the rough endoplasmic reticulum is dedicated to protein synthesis. This specialized role makes the SER essential in steroidogenic cells like those found in the adrenal glands and ovaries.
Why the other options are wrong
- A. This option is incorrect. Lysosomes are primarily involved in the breakdown of cellular waste materials and macromolecules, not in the synthesis of steroid hormones. They contain digestive enzymes that degrade proteins, lipids, and other macromolecules.
- B. This option is incorrect. The Golgi bodies, or Golgi apparatus, are involved in modifying, sorting, and packaging proteins and lipids for secretion or use within the cell. They are not directly responsible for the production of steroid hormones.
- D. This option is incorrect. The rough endoplasmic reticulum (RER) is primarily involved in the synthesis of proteins destined for secretion or for use in the cell membrane. It is not involved in the synthesis of steroid hormones.
Q60. Which of the following describes the fluid mosaic model of plasma membrane structure?
- A. Phospholipid monolayer with embedded proteins
- B. Phospholipid bilayer with embedded proteins✓
- C. Triglyceride bilayer with embedded proteins
- D. Triglyceride monolayer with embedded proteins
Explanation: The fluid mosaic model describes the plasma membrane as a phospholipid bilayer with proteins embedded throughout. This model emphasizes the flexibility of the membrane, as well as the diverse proteins that create a 'mosaic' appearance. The bilayer consists of two layers of phospholipids, with hydrophobic tails facing inward and hydrophilic heads facing outward. This arrangement provides the membrane with its fluid characteristic. Option A is incorrect as it suggests a monolayer, which is not the structure of the plasma membrane. Options C and D are incorrect because triglycerides are not the primary components of the plasma membrane; instead, phospholipids are the structural backbone.
Why the other options are wrong
- A. This option is incorrect. The plasma membrane's fluid mosaic model is characterized by a phospholipid bilayer, not a monolayer. A monolayer would only consist of a single layer of phospholipids, which does not apply to the plasma membrane structure.
- C. This option is incorrect. While triglycerides are lipids, they are not found in the plasma membrane as the primary structural element. The plasma membrane is primarily composed of a phospholipid bilayer, rather than triglycerides.
- D. This option is incorrect. Triglycerides are not the main components of the plasma membrane, and a monolayer does not accurately describe the bilayer structure of the plasma membrane in the fluid mosaic model.
Q61. How many nuclear pores are present in typical differentiated cells such as RBCs?
- A. About 3000 per nucleus
- B. About 30,000 per nucleus
- C. About 1-2 per nucleus
- D. About 3-4 per nucleus✓
- E. Zero
Explanation: The correct answer is about 3-4 nuclear pores per nucleus in fully differentiated cells such as red blood cells (RBCs). These pores are essential for the transport of molecules between the nucleus and the cytoplasm. While undifferentiated cells may possess a higher number of nuclear pores to facilitate various cellular processes, differentiated cells like RBCs have adapted to their specialized functions, resulting in a reduced number of nuclear pores. The other options either overestimate or underestimate the typical count found in these cells. For instance, egg cells possess around 30,000 nuclear pores due to their larger size and different functional demands, while stating zero would be incorrect as immature RBCs do contain nuclei.
Why the other options are wrong
- A. This option overestimates the number of nuclear pores in fully differentiated cells. Typically, they have significantly fewer.
- B. This number is accurate for certain large cells, such as egg cells, but not for differentiated cells like RBCs.
- C. This option underestimates the number of nuclear pores found in fully differentiated cells. RBCs have more pores.
- E. This option is incorrect because RBCs have nuclei during their immature stages but have a reduced number of nuclear pores when fully differentiated.
Q62. What is the correct location of ATP synthase in mitochondria?
- A. Mitochondrial matrix
- B. Inner mitochondrial membrane✓
- C. Outer mitochondrial membrane
- D. Inter-membrane space
Explanation: The correct location of ATP synthase is the inner mitochondrial membrane. ATP synthase is essential for the production of ATP, utilizing the proton gradient established by the electron transport chain across this membrane. The inner membrane's cristae offer a large surface area for ATP synthesis. In contrast, the mitochondrial matrix, while important for other metabolic processes, does not contain ATP synthase. The outer membrane serves mainly as a gateway for molecules entering and exiting the mitochondria, and the inter-membrane space is a site of proton accumulation but not where ATP synthase is located.
Why the other options are wrong
- A. This is incorrect. The mitochondrial matrix contains enzymes for the Krebs cycle but does not house ATP synthase, which is involved in ATP synthesis.
- C. This is incorrect. The outer mitochondrial membrane is involved in the transport of molecules but does not contain ATP synthase.
- D. This is incorrect. The inter-membrane space is involved in the electron transport chain, but ATP synthase itself is not located here.
Q63. The inner membrane of mitochondria form extensive infoldings called _.
- A. Cristae✓
- B. Cisternae
- C. Lamella
- D. Bifida
Explanation: The inner membrane of mitochondria is highly specialized and forms numerous infoldings known as cristae. These structures are vital as they increase the surface area of the membrane, allowing for more space for the electron transport chain and ATP synthase, which are key components in the production of ATP. The other options are incorrect: cisternae are associated with the endoplasmic reticulum and Golgi apparatus, lamella refers to a general thin layer or membrane, and bifida pertains to a medical condition unrelated to cell structure.
Why the other options are wrong
- B. Cisternae refer to the flattened, membrane-bound structures found in the endoplasmic reticulum and Golgi apparatus, not in mitochondria. Therefore, this option is incorrect.
- C. Lamella describes a thin layer or plate often associated with tissues or membranes but is not specifically related to mitochondrial structure. Hence, this option is incorrect.
- D. Bifida is a medical term for a condition related to the incomplete development of the spinal cord and is unrelated to mitochondrial anatomy. Therefore, this option is incorrect.
Q64. Below is the diagram of a bacteriophage. In which one of the options are all four parts, A, B, C, and D, correct, respectively?
- A. Tail fibres, Head, Sheath, Collar
- B. Sheath, Collar, Head, Tail fibres
- C. Head, Sheath, Collar, Tail fibres✓
- D. Collar, Tail fibres, Head, Sheath
Explanation: A–Head, B–Sheath, C–Collar, D–Tail fibreThe head contains the genetic material of the bacteriophage, usually in the form of DNA or RNA, enclosed within a protein coat. It plays a vital role in protecting the genetic material and injecting it into the host cell during infection.The sheath is a contractile structure surrounding the tail tube that helps in injecting the phage DNA into the bacterial cell. When the phage attaches to the host, the sheath contracts to push the DNA through the bacterial membrane.The collar is a small structure that connects the head to the tail and helps in stabilizing the phage during attachment. It also assists in the transfer of genetic material from the head to the tail during infection.The tail fibres are long, thin structures that help the phage recognize and attach to specific receptor sites on the bacterial surface. They play a crucial role in determining the host range and initiating the infection process.
Why the other options are wrong
- A. A–Head, B–Sheath, C–Collar, D–Tail fibre.
- B. A–Head, B–Sheath, C–Collar, D–Tail fibre.
- D. A–Head, B–Sheath, C–Collar, D–Tail fibre.
Q65. Which of the following statements is wrong for viroids?
- A. They cause infections
- B. Their RNA is of high molecular weight✓
- C. They lack a protein coat
- D. They are smaller than viruses
Explanation: "Their RNA is of high molecular weight" This statement is Incorrect. Viroids have RNA that is of very low molecular weight. In fact, one of the distinguishing features of viroids is their small size, as they consist of a single-stranded RNA molecule with a low molecular weight. This sets them apart from viruses, which typically have larger and mare complex genomes.
Why the other options are wrong
- A. This statement is correct. Viroids are known to cause infections, specifically in plants, leading to significant agricultural impacts. They are small, infectious RNA molecules that can disrupt normal plant functions.
- C. This statement is correct. Unlike viruses, viroids do not have a protein coat or capsid. Their structure consists solely of a small, circular RNA molecule, which is a key feature that differentiates them from viruses.
- D. This statement is correct. Viroids are indeed smaller than viruses, being some of the smallest known infectious agents, comprised of a single circular RNA molecule that is usually just a few hundred nucleotides long.
Q66. Which of the following statements is not true for retroviruses?
- A. DNA is not present at any stage in the life cycle of retroviruses✓
- B. Retroviruses carry a gene for RNA-dependent DNA polymerase
- C. The genetic material in mature retroviruses is RNA
- D. Retroviruses are causative agents for certain kinds of cancer in humans
Explanation: Retroviruses are unique viruses with a complex life cycle, and their features help explain which statements are true or false. Statement (a) is false because retroviruses indeed have a DNA stage in their replication cycle. After infection, they use the enzyme reverse transcriptase to convert their RNA genome into DNA, which integrates into the host cell’s chromosomes. Statement (b) is true because retroviruses encode RNA-dependent DNA polymerase, better known as reverse transcriptase, which is essential for converting viral RNA into DNA. Statement (c) is also true since retroviruses carry RNA as their genetic material inside mature virions, which is used as a template after infection. Finally, statement (d) is true because some retroviruses, such as HTLV-1, are oncogenic, meaning they can disrupt normal host cell growth regulation and potentially cause cancers like adult T-cell leukaemia. These features distinguish retroviruses from other types of viruses.
Why the other options are wrong
- B. This statement is true. Retroviruses carry the gene for reverse transcriptase, which is also known as RNA-dependent DNA polymerase. This enzyme is responsible for transcribing the viral RNA into DNA.
- C. This statement is true. Retroviruses store their genetic information as RNA. However, during the replication process, they reverse transcribe this RNA into DNA, which becomes integrated into the host cell's genome.
- D. This statement is true. Some retroviruses are known to be oncogenic, meaning they can cause cancer in humans. For example, the human T-cell lymphotropic virus type 1 (HTLV-1) is associated with the development of adult T-cell leukaemia (a form of cancer).
Q67. Name the pulmonary disease in which alveolar surface area involved in gas exchange is drastically reduced due to damage in the alveolar walls:
- A. Pneumonia
- B. Asthma
- C. Pleurisy
- D. Emphysema✓
Explanation: In emphysema, the walls of the alveoli are damaged, leading to fewer and larger air sacs instead of many small ones. This reduces the surface area for gas exchange and causes breathing difficulties.
Why the other options are wrong
- A. Pneumonia is an inflammatory lung condition primarily caused by infection, not by damage to the alveolar walls. It typically results in the air sacs (alveoli) filling with fluid or pus due to infection, rather than damage to alveolar walls.
- B. Asthma is a chronic respiratory condition characterized by airway inflammation, bronchoconstriction, and excess mucus production. It does not primarily involve damage to the alveolar walls but rather affects the airways.
- C. Pleurisy, or pleuritis, is inflammation of the pleura, the lining around the lungs. It does not directly involve damage to the alveolar walls or impact the alveolar surface area responsible for gas exchange.
Q68. Lipid bilayer makes the membrane differently permeable barrier that allows the transport of:
- A. Ionic materials
- B. Polar materials
- C. Non-polar materials✓
- D. Glycoproteins
Explanation: The lipid bilayer of the plasma membrane is composed mainly of phospholipids, which have hydrophobic tails and hydrophilic heads. This structure creates a barrier that is selectively permeable. Non-polar materials can dissolve in the hydrophobic core of the bilayer, allowing them to pass through easily. In contrast, ionic and polar materials, such as ions and polar molecules, are repelled by the hydrophobic core and require specific transport proteins to facilitate their movement across the membrane. Glycoproteins, being large and complex, also require specialized transport mechanisms.
Why the other options are wrong
- A. Ionic materials, due to their charge, cannot easily pass through the non-polar environment of the lipid bilayer without assistance from transport proteins.
- B. Polar molecules struggle to pass through the lipid bilayer because its hydrophobic interior repels them. Non-polar molecules can diffuse more easily. Transport of polar substances usually requires protein channels or carriers.
- D. Glycoproteins are large, complex molecules that cannot pass through the lipid bilayer directly; they require specific mechanisms to be transported across the membrane.
Q69. _ enzyme needs a primer for the initiation of its function.
- A. RNA polymerase
- B. DNA polymerase✓
- C. Primase
- D. Ligase
Explanation: The synthesis of a primer is necessary because DNA polymerases, can only attach new DNA nucleotides to an existing strand of nucleotides. The primer therefore serves to prime and lay a foundation for DNA synthesis.
Why the other options are wrong
- A. RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, during the process of transcription.The enzyme RNA polymerase interacts with proteins to enable it to function in catalyzation of the synthesis of RNA.A primer is a short piece of nucleic acid that some polymerases require to initiate nucleic acid synthesis. This piece of nucleic acid could be a DNA or RNA. RNA polymerase is one of the polymerases that don’t require a primer.
- C. Primase is an enzyme that creates a primer on a DNA strand by adding RNA nucleotides to the strand according to the DNA template sequence.
- D. Ligase an enzyme that catalyzes the joining of two molecules by forming a covalent bond accompanied by the hydrolysis of ATP also called synthetase.
Q70. Male having Down's syndrome have sex chromosomes:
- A. XXY
- B. XY✓
- C. XYY
- D. XYYY
Explanation: In Down’s syndrome, the affected person contains an extra autosomal chromosome number 21 (trisomy 2n+1). Males having this syndrome have XY sex chromosomes. They have 3 21st chromosomes.
Why the other options are wrong
- A. XXY represents Klinefelter's syndrome, where males have an extra X chromosome, but it is unrelated to Down's syndrome, which involves an autosomal chromosome.
- C. XYY syndrome is a separate chromosomal disorder affecting males, characterized by an additional Y chromosome, not associated with Down's syndrome.
- D. XYYY syndrome is an exceedingly rare chromosomal disorder involving multiple extra Y chromosomes and does not relate to Down's syndrome.
Q71. Given the reaction: C3H8 + 5O2 → 3CO2 + 4H2O At STP , how many litres of O2 are needed to completely burn 5.0 litres of C3H8?
- A. 5
- B. 10
- C. 10.5
- D. 15
- E. 25✓
Explanation: Consider that no. of moles of reactants = volume of the reactants.As the molar ratio between C3H6 and O2 is 1:5, the volume ratio is also the same. For 1L of C3H6 we need 5L of O2. Since the volume of C3H6 is 5L now, to burn this, we require 25L of O2.All other options are incorrect because they do not follow the exact mole-volume relationship required in this case.
Why the other options are wrong
Q72. The partial pressure of oxygen in the alveoli of the lungs is:
- A. Equal to that in the blood
- B. More than that in the blood✓
- C. Less than that in the blood
- D. Less than that of carbon dioxide.
Explanation: The partial pressure of oxygen in the alveoli is higher than in the blood, facilitating the diffusion of oxygen from the alveoli into the blood, where it can be transported by hemoglobin to tissues throughout the body.
Why the other options are wrong
- A. This option is incorrect. If the partial pressures were equal, there would be no net movement of oxygen from the alveoli to the blood. The alveoli must have a higher partial pressure to drive diffusion of oxygen into the bloodstream.
- C. This option is incorrect. If the partial pressure of oxygen in the alveoli were less than in the blood, oxygen would not move into the bloodstream as required for proper physiological function. The direction of diffusion relies on a higher concentration of oxygen in the alveoli.
- D. This option is incorrect. The partial pressure of oxygen in the alveoli is higher than that of carbon dioxide to ensure efficient oxygen uptake and carbon dioxide removal during respiration.
Q73. Lungs do not collapse between breaths, and some air always remains in the lungs, which can never be expelled because:
- A. There is a negative pressure in the lungs
- B. There is a negative intrapleural pressure pulling at the lung walls✓
- C. There is a positive intrapleural pressure
- D. Pressure in the lungs is higher than atmospheric pressure
Explanation: Option B is correct.All options are explained below:a)There is a negative pressure in the lungs."This statement is not entirely accurate. Lungs don't naturally have a negative pressure, and they can't be filled with air if there is a consistent negative pressure. Lungs maintain a degree of positive pressure to keep them expanded.b) "There is a negative intrapleural pressure pulling at the lung walls": This option is correct. Between breaths, the lungs do not collapse due to the presence of a negative intrapleural pressure. Intrapleural pressure is the pressure in the pleural cavity, which surrounds the lungs. It is typically lower than atmospheric pressure, creating a "suction" effect that keeps the lungs inflated. This is a key mechanism for lung expansion and prevents lung collapse.c)"There is a positive intrapleural pressure": This statement is not accurate. A positive intrapleural pressure would not be conducive to maintaining lung expansion; it's the negative intrapleural pressure that plays a critical role in preventing lung collapse.d)"Pressure in the lungs is higher than the atmospheric pressure": This is not correct. The pressure in the lungs, during exhalation, is generally close to atmospheric pressure, but it's the intrapleural pressure that is negative, not the pressure in the lungs themselves.Summary: The correct answer is: "There is a negative intrapleural pressure pulling at the lung walls." The negative intrapleural pressure, which is lower than atmospheric pressure, keeps the lungs expanded by exerting a suction effect on the lung walls, preventing lung collapse between breaths.
Why the other options are wrong
- A. This statement is misleading. The pressure inside the lungs is not negative; rather, it's the intrapleural pressure that is negative, helping to keep the lungs expanded. Positive pressure inside the lungs is necessary for normal breathing cycles.
- C. This is incorrect. A positive intrapleural pressure would push against the lung walls, leading to collapse rather than maintaining expansion. The negative pressure in the pleural cavity is what keeps the lungs inflated.
- D. This is not accurate. The pressure within the lungs during normal breathing cycles is generally around atmospheric pressure, but the key factor preventing lung collapse is the negative intrapleural pressure, not the pressure inside the lungs.
Q74. Reduction in pH of blood will directly cause which of the following?
- A. Decrease the affinity of haemoglobin with oxygen✓
- B. Release bicarbonate ions by the liver
- C. Reduce the rate of heart beat
- D. Reduce the blood supply to the brain.
Explanation: A reduction in blood pH (an increase in acidity) is typically associated with a condition called acidosis. In acidosis, the affinity of hemoglobin for oxygen decreases. This means that hemoglobin is less effective at binding with oxygen, which can lead to impaired oxygen transport to tissues.
Why the other options are wrong
- B. This option is not accurate. Bicarbonate ions are primarily released and regulated by the kidneys, not the liver. In cases of acidosis, the kidneys can help by increasing the production and release of bicarbonate ions into the bloodstream to help buffer the excess acid.
- C. This statement is not correct. In most cases, a reduction in blood pH (acidosis) can actually have the opposite effect and increase the heart rate as the body attempts to compensate for the acidosis by delivering more oxygen to tissues.
- D. This option is not generally accurate. Acidosis can affect cerebral blood flow regulation, but it doesn't necessarily reduce blood supply to the brain. It can have complex effects, including the potential to increase cerebral blood flow in some cases.
Q75. Asthma may be attributed to:
- A. Inflammation of the trachea
- B. Accumulation of fluid in the lungs
- C. Bacterial infection of the lungs
- D. Allergic reaction of the mast cells in the lungs✓
Explanation: Asthma is often associated with allergic reactions where allergens trigger the activation of mast cells in the lungs. These cells release chemicals like histamines, leading to airway inflammation and bronchoconstriction, which are hallmarks of asthma.
Why the other options are wrong
- A. This option is incorrect. While asthma involves inflammation, it primarily affects the bronchi and bronchioles, not the trachea. Asthma is characterized by chronic inflammation of these smaller airways, leading to symptoms like wheezing and shortness of breath.
- B. This option is incorrect. Fluid accumulation in the lungs is more indicative of conditions like pulmonary edema, often related to heart failure, rather than asthma. Asthma is primarily about airway inflammation and constriction.
- C. This option is incorrect. While bacterial infections can exacerbate asthma symptoms, they are not a direct cause of asthma. Asthma is primarily an inflammatory condition often linked to allergic reactions.
Q76. The net pressure gradient that causes the fluid to filter out of the glomeruli into the capsule is:
- A. 50 mm Hg
- B. 75 mm Hg
- C. 20 mm Hg✓
- D. 30 mm Hg
Explanation: The net filtration pressure in the glomeruli, which facilitates the movement of fluid into the Bowman’s capsule, is determined by subtracting the opposing pressures from the blood pressure in the glomeruli. The blood pressure in the glomeruli is approximately 70 mm Hg. This is counteracted by the osmotic pressure of plasma proteins (approximately 30 mm Hg) and the hydrostatic pressure in the Bowman’s capsule (approximately 20 mm Hg). Thus, the net filtration pressure is 70 - (30 + 20) = 20 mm Hg. This net pressure is crucial for the filtration process, allowing water and small solutes to pass from the blood into the nephron. Options A, B, and D represent different pressure components but not the net filtration pressure, making option C the correct answer.
Why the other options are wrong
- A. 50 mm Hg is higher than the net filtration pressure. It might represent a component of the pressures involved but not the net pressure.
- B. 75 mm Hg is the approximate pressure of blood entering the glomeruli, not the net filtration pressure.
- D. 30 mm Hg is the osmotic pressure due to plasma proteins inside the glomerular capillaries, not the net pressure.
Q77. Name the chronic respiratory disorder caused mainly by cigarette smoking.
- A. Respiratory acidosis
- B. Respiratory alkalosis
- C. Emphysema✓
- D. Asthma
Explanation: Emphysema is a chronic respiratory disorder primarily caused by cigarette smoking, leading to damaged lung tissue and breathing difficulties.
Why the other options are wrong
- A. Respiratory acidosis involves excess carbon dioxide in the blood due to respiratory failure, but it's not directly caused by cigarette smoking.
- B. Respiratory alkalosis is characterized by decreased carbon dioxide levels due to hyperventilation, unrelated to chronic smoking.
- D. Asthma is a chronic condition that can be worsened by smoking, but it is not mainly caused by smoking and has various triggers.
Q78. Name the pulmonary disease in which alveolar surface area involved in gas exchange is drastically reduced due to damage in the alveolar walls:
- A. Pneumonia
- B. Asthma
- C. Pleurisy
- D. Emphysema✓
Explanation: In emphysema, the walls of the alveoli are damaged, leading to fewer and larger air sacs instead of many small ones. This reduces the surface area for gas exchange and causes breathing difficulties.
Why the other options are wrong
- A. Pneumonia is an inflammatory lung condition primarily caused by infection, not by damage to the alveolar walls. It typically results in the air sacs (alveoli) filling with fluid or pus due to infection, rather than damage to alveolar walls.
- B. Asthma is a chronic respiratory condition characterized by airway inflammation, bronchoconstriction, and excess mucus production. It does not primarily involve damage to the alveolar walls but rather affects the airways.
- C. Pleurisy, or pleuritis, is inflammation of the pleura, the lining around the lungs. It does not directly involve damage to the alveolar walls or impact the alveolar surface area responsible for gas exchange.
Q79. When you hold your breath, which of the following gas changes in blood would first lead to the urge to breathe?
- A. Falling CO2 concentration
- B. Rising CO2 and falling O2 concentration
- C. Falling O2 concentration
- D. Rising CO2 concentration✓
Explanation: During breath-holding, the accumulation of CO in the blood is the primary factor that triggers the urge to breathe. This rise in CO concentration stimulates the respiratory center in the brain, prompting the body to resume breathing to expel excess CO and maintain homeostasis.
Why the other options are wrong
- A. A decrease in CO2 concentration is not the primary trigger for the urge to breathe when holding your breath. Lower CO2 levels, often resulting from hyperventilation, do not naturally occur during breath-holding and do not stimulate the urge to breathe.
- B. While both rising CO2 and falling O2 concentrations can occur during breath-holding, the primary stimulus for the urge to breathe is the increase in CO2 levels. A decrease in O2 plays a secondary role.
- C. A decrease in O2 concentration can lead to symptoms like shortness of breath, but it is not the main trigger for the urge to breathe during breath-holding. The rising CO2 concentration is the primary trigger.
Q80. Approximately seventy percent of carbon dioxide absorbed by the blood will be transported to the lungs
- A. As bicarbonate ions✓
- B. In the form of dissolved gas molecules
- C. By binding to R.B.C
- D. As carbamino haemoglobin.
Explanation: The correct option is a) as bicarbonate ions.Explanation of each option:A. As bicarbonate ions (Correct Option): Approximately seventy percent of carbon dioxide (CO2) absorbed by the blood is transported in the form of bicarbonate ions (HCO3-). This is the primary method for CO2 transport in the blood. It involves a chemical reaction where CO2 combines with water (H2O) to form carbonic acid (H2CO3), which rapidly dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+). This bicarbonate ion is then carried in the bloodstream to the lungs for elimination.B. In the form of dissolved gas molecules: Some CO2 (around 7-10%) is transported in the bloodstream as dissolved gas molecules in plasma. However, this is a relatively small fraction compared to the bicarbonate ion transport method.C.By binding to R.B.C (Red Blood Cells): A smaller portion of CO2 (around 20-23%) binds to hemoglobin within red blood cells, forming carbamino compounds. This is a significant but secondary method compared to bicarbonate ion transport.D. As carbamino-hemoglobin: This option refers to the CO2 that binds to hemoglobin within red blood cells. It is a less dominant method of CO2 transport compared to bicarbonate ions.Brief Summary: Approximately seventy percent of carbon dioxide (CO2) absorbed by the blood is transported as bicarbonate ions (HCO3-). This process involves the conversion of CO2 to bicarbonate ions in a chemical reaction and is the primary method for CO2 transport in the bloodstream. While CO2 can also be transported as dissolved gas molecules, by binding to red blood cells, and as carbamino compounds, these are secondary methods in comparison to the predominant bicarbonate ion transport.
Why the other options are wrong
- B. In the form of dissolved gas molecules: Some CO2 (around 7-10%) is transported in the bloodstream as dissolved gas molecules in plasma. However, this is a relatively small fraction compared to the bicarbonate ion transport method.
- C. By binding to R.B.C (Red Blood Cells): A smaller portion of CO2 (around 20-23%) binds to hemoglobin within red blood cells, forming carbamino compounds. This is a significant but secondary method compared to bicarbonate ion transport.
- D. As carbamino-hemoglobin: This option refers to the CO2 that binds to hemoglobin within red blood cells. It is a less dominant method of CO2 transport compared to bicarbonate ions.
Q81. Photophosphorylation takes place in the _ of the chloroplasts:
- A. Stroma
- B. Granum✓
- C. Inner membrane
- D. Outer membrane
Explanation: Photophosphorylation takes place in the thylakoid membrane of the chloroplasts. This process, part of the light-dependent reactions of photosynthesis, uses light energy to create a proton gradient across the thylakoid membrane, which then drives the synthesis of ATP from ADP and inorganic phosphate.
Why the other options are wrong
- A. This is not correct. Photophosphorylation takes place in the thylakoid membrane of the chloroplasts. The thylakoid membrane is a membrane system within the chloroplast that contains chlorophyll and other pigments involved in capturing light energy during the light-dependent reactions of photosynthesis. Calvin cycle takes place in stroma.
- C. The inner membrane of a chloroplast is a selective barrier that controls the movement of molecules between the stroma and the cytosol. Not involved in photophosphorylation.
- D. Is responsible for movement of particles across it, not related to photophosphorylation.
Q82. A person who is on a long hunger strike and is surviving only on water, will have:
- A. Less amino acids in his urine
- B. More glucose in his blood
- C. Less urea in his urine✓
- D. More sodium in his urine.
Explanation: During starvation, the body must rely on body proteins for the amino acids. On high protein diets the carbon skeletons of the amino acids are oxidized for energy or stored as fat and glycogen, but the amino nitrogen must be excreted. To facilitate this process, enzymes of the urea cycle are controlled at the gene level. When dietary proteins increase significantly, enzyme concentrations rise. On return to a balanced diet, enzyme levels decline. Under conditions of starvation, enzyme levels rise as proteins are degraded and amino acid carbon skeletons are used to provide energy, thus increasing the quantity of nitrogen that must be excreted in the form of urea.
Why the other options are wrong
- A. This is incorrect because starvation leads to the breakdown of body proteins, increasing amino acid breakdown products in the urine.
- B. This is incorrect because during prolonged fasting, blood glucose levels tend to decrease as glycogen stores are depleted to provide for the decreasing energy levels.
- D. This is incorrect because sodium levels are typically conserved during fasting to maintain electrolyte balance.
Q83. The experiments by Hershey and Chase helped confirm that DNA was the hereditary material on the basis of the finding that :
- A. Radioactive phage were found in the pellet
- B. Radioactive cells were found in the supernatant
- C. Radioactive sulfur was found inside the cell
- D. Radioactive phosphorus was found in the cell✓
Explanation: The experiments by Hershey and Chase helped confirm that DNA was the hereditary material as radioactive phosphorus was found in the cell.The Hershey-Chase experiments were not the first studies to oppose the prevailing theory in the early 1900s that genetic material was composed of proteins. In 1944, nearly a decade before Hershey and Chase’s work, scientists published sound evidence that genes were made of DNA rather than protein so it was confirmed by presence of phosphorus.
Why the other options are wrong
- A. In Hershey and Chase's famous experiment, they used two different radioactive isotopes to label the components of the bacteriophage T2 virus. They used radioactive sulfur-35 (32S) to label the protein coat of the phage and radioactive phosphorus-32 (32P) to label the DNA of the phage. After allowing the labeled phages to infect the bacterial cells, they used a blender and centrifugation to separate the phage protein coats (empty phage) from the bacterial cells.
- B. The radioactive protein coats (labeled with 32S) remained in the supernatant, but the radioactive DNA (labeled with 32P) entered the bacterial cells and was found in the pellet.
- C. Radioactive sulfur-35 (32S) was used to label the protein coat of the phage, it was found in the supernatant outside the bacterial cells and not inside the cells.
Q84. If the medulla oblongata of a person brain is damaged which of the following process will be disturbed?
- A. Thinking
- B. Sleep
- C. Thirst
- D. Swallowing✓
Explanation: The medulla oblongata is a structure found in the human brain. The major function of the Medulla oblongata is to control automatic functions (that is, not under human control) breathing, respiration, and heartbeat. It also helps in body secretion, reflexes, swallowing, coughing, and sneezing.
Why the other options are wrong
- A. The cerebrum is the biggest part of the brain. The cerebrum is the thinking part of the brain. It is also concerned with conscious sensation, voluntary movements, learning, memory, decision making, reasoning, and judgment.
- B. The hypothalamus, a peanut-sized structure deep inside the brain, contains groups of nerve cells that act as control centres affecting sleep and arousal.
- C. The hypothalamus is responsible for controlling thirst.
Q85. For which purpose are myeloma cells (cancerous B lymphocytes) used in the production of monoclonal antibodies?
- A. Increased rate of cell division
- B. Immunization with antigen✓
- C. To avoid contamination
- D. As nutrient in media
Explanation: Multiple myeloma cells are abnormal plasma cells (a type of white blood cell) that build up in the bone marrow and form tumors in many bones of the body. They are produced for immunization with an antigen, as Vaccines contain weakened or inactive parts of a particular organism (antigen) that triggers an immune response within the body.
Why the other options are wrong
- A. Myeloma cells (cancerous B lymphocytes) are used in the production of monoclonal antibodies, not to increase the rate of cell division.
- C. Myeloma cells (cancerous B lymphocytes) are used in the production of monoclonal antibodies, not to avoid contamination.
- D. Myeloma cells (cancerous B lymphocytes) are used in the production of monoclonal antibodies, not as a nutrient in media.
Q86. An autoimmune disorders in which stiffness and inflammation of vertebrae occurs is called as:
- A. Lupus
- B. Scleroderma
- C. Ankylosing spondylitis✓
- D. Juvenile dermatomyositis
Explanation: An autoimmune disorder in which stiffness and inflammation of vertebrae occur is called Ankylosis spondylitis.
Why the other options are wrong
- A. Lupus is an autoimmune disease that can cause joint pain and inflammation, but it primarily affects the skin, kidneys, and other organs rather than specifically targeting the spine.
- B. Scleroderma involves hardening and tightening of the skin and connective tissues, but it does not primarily target the vertebrae or cause spinal inflammation.
- D. Juvenile dermatomyositis is an inflammatory condition affecting the skin and muscles, particularly in children, and does not typically involve the vertebrae.
Q87. Choose reaction that is not correct?
- A. Option A: Acetic acid reacts with sodium to form sodium acetate and hydrogen gas.
- B. Option B: Acetic acid reacts with ethanol in the presence of sulfuric acid to form ethyl acetate and water.
- C. Option C: Acetic acid reacts with phosphorus pentoxide to form acetic anhydride.
- D. Option D: Acetic acid reacts with ammonia to form acetyl chloride and water.✓
Explanation: The correct answer is Option D. Acetic acid does not react with ammonia to form acetyl chloride and water; instead, it usually forms ammonium acetate. Options A, B, and C describe well-established reactions: A is the reaction with sodium forming sodium acetate, B is esterification with ethanol forming ethyl acetate, and C is dehydration with phosphorus pentoxide forming acetic anhydride.
Why the other options are wrong
- A. This option is correct. The reaction of acetic acid with sodium is a well-known reaction that produces sodium acetate and hydrogen gas.
- B. This option is correct. This describes esterification, a common reaction where acetic acid and ethanol produce ethyl acetate and water.
- C. This option is correct. When acetic acid reacts with phosphorus pentoxide, it dehydrates to form acetic anhydride, which is the expected outcome.
Q88. A person is undergoing prolonged fasting. His urine will be found to contain abnormal quantities of:
- A. Fats
- B. Amino acids
- C. Glucose
- D. Ketones✓
Explanation: During prolonged fasting, the body relies on fat stores for energy, leading to increased fatty acid oxidation in the liver. This process produces ketone bodies such as acetoacetate, b-hydroxybutyrate, and acetone. The presence of excess ketone bodies in urine is termed as ketonuria, indicating a state of increased fat metabolism. While fats, amino acids, and glucose can also be present in urine under certain conditions, the abnormal quantities of ketones in the urine during prolonged fasting specifically point towards increased fatty acid oxidation and the risk of diabetic ketoacidosis.
Why the other options are wrong
- A. During prolonged fasting, the body breaks down fats into fatty acids, which are converted in the liver into ketone bodies. Excess ketones appear in urine (ketonuria), not fats.
- B. During prolonged fasting, amino acids are mostly used for gluconeogenesis in the liver, and their nitrogen is converted to urea for excretion. Large amounts of amino acids in urine are typically not found unless there is a kidney disorder; instead, find excess ketone bodies in urine are found (ketonuria).
- C. In prolonged fasting, blood glucose is low and conserved for vital organs, so the kidneys don't excrete glucose. Instead, fat breakdown leads to ketone body formation, and these ketones appear in urine (ketonuria), not glucose.
Q89. Low partial pressure of oxygen in tissues favors _ of oxyheamoglobin.
- A. Dissociation✓
- B. Stability
- C. Formation
- D. Transformation
Explanation: More CO2, less O2, high temperature and less pH facilitate oxygen dissociation from oxyhaemoglobin.When the partial pressure of oxygen (PO2) is low in the tissues, it indicates that the tissues are in need of oxygen supply. In this situation, according to the principle of the oxygen-hemoglobin dissociation curve, hemoglobin's affinity for oxygen decreases. As a result, the oxyhemoglobin complex readily releases its bound oxygen molecules, allowing the oxygen to diffuse from the blood into the tissues where it is needed for cellular respiration and metabolism.This phenomenon is a crucial aspect of the Bohr effect, which refers to the influence of pH, carbon dioxide (CO2) concentration, and partial pressure of oxygen on hemoglobin's ability to bind and release oxygen. In metabolically active tissues with higher CO2 levels and increased hydrogen ion (H+) concentration (lower pH), the partial pressure of oxygen is lower, and this environment favors the release of oxygen from oxyhemoglobin, enabling efficient oxygen delivery to the tissues. Conversely, in the lungs where oxygen levels are high, hemoglobin readily binds to oxygen, forming oxyhemoglobin for efficient oxygen transport from the lungs to the tissues.
Why the other options are wrong
- B. Stability of oxyhemoglobin occurs at high oxygen pressure, such as in the lungs. Low tissue oxygen pressure does not promote stability; rather, it promotes release.
- C. Formation of oxyhemoglobin occurs in the lungs, where oxygen pressure is high. In tissues with low O2 pressure, formation is not favored.
- D. Transformation is a vague term and not specifically used to describe the oxygen-hemoglobin interaction under physiological conditions.
Q90. About 70-85% CO2 in blood is carried:
- A. As carboxylase myoglobin
- B. Freely as CO2
- C. With proteins in plasma
- D. As bicarbonate✓
Explanation: About 70% of CO2 is transported as bicarbonate ions.
Why the other options are wrong
- A. It is not carried out as carboxylase myoglobin
- B. CO2 is not transported freely instead it is bound to substances such as bicarbonates and blood plasma etc
- C. CO2 is not carried by proteins
Q91. Quantum number which describes the orientation of orbitals in three dimensional space is:
- A. Spin quantum number
- B. Azimuthal quantum number
- C. Magnetic quantum number✓
- D. Principal quantum number
Explanation: Magnetic Quantum Number (m) : Gives the orientation of the orbital in space; in other words, the value of m describes whether an orbital lies along the x-, y-, or z-axis on a three-dimensional graph, with the nucleus of the atom at the origin. m can take on any value from −ltol. Hence option C is correct.
Why the other options are wrong
- A. The Spin Quantum Number (ms) describes the angular momentum of an electron. An electron spins around an axis and has both angular momentum and orbital angular momentum. Because angular momentum is a vector, the Spin Quantum Number (s) has both a magnitude (1/2) and direction (+ or -).
- B. The azimuthal (or orbital angular momentum) quantum number describes the shape of a given orbital. It is denoted by the symbol 'l'.A value of the azimuthal quantum number can indicate either an s, p, d, or f subshell which vary in shape.
- D. The principal quantum number, n, describes the energy of an electron and the most probable distance of the electron from the nucleus. In other words, it refers to the size of the orbital and the energy level an electron is placed in.
Q92. Substance that has sharp melting point in the following is:
- A. Gemstone
- B. Coal tar
- C. Glass
- D. Diamond✓
Explanation: Each carbon atom is covalently bonded to four other carbon atoms in diamond. A lot of energy is needed to separate the atoms. This is because covalent bonds are strong. This is the reason why diamond has a high melting point.
Why the other options are wrong
- A. Gemstone is a solid solution and comparetively high melting point but diamond is the hardest molecule and has high melting point than gemstone.
- B. Coal tar is a thick dark liquid and in liquid atoms have more space between them than solids so have low melting point
- C. Coal tar is a thick dark liquid and in liquid atoms have more space between them than solids so have low melting point
Q93. Which of the following pairs is an example of completely immiscible liquids?
- A. Alcohol and water
- B. Alcohol and ether
- C. Water and ether
- D. Carbon disulphide and water✓
Explanation: CS2 is insoluble in water and more dense (10.5 lb/gal) than water. Hence sinks in water.
Why the other options are wrong
- A. Alcohol and water are miscible due to H bonding
- B. Alcohol and ether are also miscible because ether can form H-bond with alcohol oxygen
- C. Water and ether are also miscible because ether can form hydrogen bond with water oxygen
Q94. The number of isomers of pentane is:
- A. 2
- B. 4
- C. 5
- D. 3✓
Explanation: Pentane (C5H12) is an organic compound with five carbon atoms. Pentane has three isomers that are n-pentane, Iso-pentane (methyl butane) and neopentane (dimethylpropane). Therefore three isomers can be drawn from pentane.
Why the other options are wrong
- A. This option is incorrect. Pentane has three structural isomers.
- B. This option is incorrect. Pentane has three structural isomers.
- C. This option is incorrect. Pentane has three structural isomers.
Q95. The compound which has the higher boiling point in the following is:
- A. Methyl chloride
- B. Methyl iodide✓
- C. Methyl bromide
- D. Both a and b
Explanation: For the same alkyl group the boiling points of haloalkanes are in the order RCl < RBr < RI, because with the increase in the size of halogen atom the magnitude of van der Waal forces of attraction increases. Hence the order of boiling points is Methyl chloride (CH3Cl) < methyl bromide (CH3Br) < methyl iodide (CH3I).
Why the other options are wrong
- A. In methyl chloride, chloride has small size and have less magnitude of van der waal forces of attraction and low polarizability thus have low boiling point
- C. In methyl bromine, the size of bromine is intermediate between chlorine and iodine and thus also has boiling point between them
- D. This is incorrect.
Q96. Which one of the following is addition polymer:
- A. Nylon
- B. PVC
- C. Polythene
- D. Both PVC and Polythene✓
Explanation: In addition polymerization (sometimes called chain-growth polymerization), a chain reaction adds new monomer units to the growing polymer molecule one at a time through double or triple bonds in the monomerOn the other hand, condensation polymerization is a process that involves repeated condensation reactions between tri-functional or bi-functional monomers with elimination of small molecules.
Why the other options are wrong
- A. Nylon is a type of condensation polymer called a polyamide.
- B. Polyvinyl chloride is produced in an addition polymerisation reaction using the chloroethene (vinyl chloride) monomer.
- C. Polyethylene is an addition polymer that is created by the polymerization of ethylene monomer units.
Q97. Which one is more reactive?
- A. HCHO✓
- B. CH3 CHO
- C. (CH3)2CO
- D. Have equal reactivity
Explanation: Aldehydes are usually more reactive toward nucleophilic substitutions than ketones because of both steric and electronic effects. In aldehydes, the relatively small hydrogen atom is attached to one side of the carbonyl group, while a larger R group is affixed to the other side. In ketones, however, R groups are attached to both sides of the carbonyl group. Thus, steric hindrance is less in aldehydes than in ketones. Electronically, aldehydes have only one R group to supply electrons toward the partially positive carbonyl carbon, while ketones have two electron‐supplying groups attached to the carbonyl carbon. The greater amount of electrons being supplied to the carbonyl carbon, the less the partial positive charge on this atom and the weaker it will become as a nucleus.
Why the other options are wrong
- B. Acetaldehyde (CH3CHO) is less reactive than formaldehyde. While it still contains a carbonyl group, the presence of a methyl group introduces some steric hindrance around the carbonyl carbon, reducing its reactivity compared to formaldehyde. This steric hindrance makes the carbonyl carbon less accessible to nucleophiles, resulting in lower reactivity.
- C. Acetone ((CH3)2CO) is a ketone, which generally exhibits lower reactivity compared to aldehydes. The presence of two methyl groups in acetone introduces significant steric hindrance around the carbonyl carbon, further reducing its reactivity compared to both formaldehyde and acetaldehyde. The additional alkyl groups in ketones make the carbonyl carbon less susceptible to nucleophilic attack, contributing to acetone's lower reactivity compared to the other compounds
- D. As per the explanation, this option is incorrect.
Q98. For exothermic reversible reaction, the activation energy for forward direction depends upon:
- A. Temperature
- B. Nature of reactant✓
- C. Nature of product
- D. Both Temperature and Nature of reactant
Explanation: For exothermic reversible reaction activation energy for forward direction depends upon nature of reactant.
Why the other options are wrong
- A. Temperature doesn't change the activation energy but increases the no.of molecules crossing this energy Barrier.
- C. Nature of product has no relation with activation energy.
- D. For exothermic reversible reaction activation energy for forward direction depends upon nature of reactant.
Q99. As the polarizing power of cation increases thermal stability of carbonates:
- A. Increases
- B. Decreases✓
- C. Not dependent
- D. Depends upon pressure
Explanation: As the polarizing power of the cation increases, it polarizes the carbonate (anion). The nucleus of the cation attracts electrons of anion causing a decrease in its thermal stability.
Why the other options are wrong
- A. As the polarizing power of the cation increases, it polarizes the carbonate (anion). The nucleus of the cation attracts electrons of anion causing a decrease in its thermal stability.
- C. As the polarizing power of the cation increases, it polarizes the carbonate (anion). The nucleus of the cation attracts electrons of anion causing a decrease in its thermal stability.
- D. As the polarizing power of the cation increases, it polarizes the carbonate (anion). The nucleus of the cation attracts electrons of anion causing a decrease in its thermal stability.
Q100. Which ions are used as catalysts in the reaction between persulfate ions and iodide ions?
- A. Lead
- B. Iron✓
- C. Copper
- D. Chromium
Explanation: Fe 2+ and Fe3+ ions are used as catalysts in this reaction since both the reactants are negatively charged, they repel each other, leading to a high activation energy.
Why the other options are wrong
- A. Iron(III) catalyzes the reaction between iodide and persulphate ions.
- C. Iron(III) catalyzes the reaction between iodide and persulphate ions.
- D. Iron(III) catalyzes the reaction between iodide and persulphate ions.
Q101. Which one is stronger nucleophile?
- A. C2H5O
- B. C2H5S✓
- C. Both are equally strong
- D. None of the above
Explanation: C2H5S- is the stronger nucleophile due to the positive inductive effect from the alkyl group and since sulfur has more electrons than oxygen, it is attracted toward the center of a positive charge.
Why the other options are wrong
- A. C2H5S- is the stronger nucleophile.
- C. C2H5S- is the stronger nucleophile.
- D. C2H5S- is the stronger nucleophile.
Q102. C4H11N gives the type of isomerism:
- A. Metamerism✓
- B. Optical isomerism
- C. Tautomerism
- D. None
Explanation: It gives metamerism which is when compounds having the same molecular formula but different alkyl groups on either side of functional groups.
Why the other options are wrong
- B. Optical isomerism is a type of stereoisomerism in which the isomers have the same molecular formula and the structural formula but differ in their direction of rotation of plane polarized light. It is limited to cycloalkane and alkene.
- C. Shifting of proton within molecule is termed as tautomerism. C4H11N doesn't show tautomerism.
- D. This option is incorrect as option a is correct.
Q103. Hydration of hydrocarbon give carbonyl compound, the general formula of that hydrocarbon is:
- A. CnH2n+2
- B. CnH2n
- C. CnH2n-2✓
- D. Both CnH2n and CnH2n-2
Explanation: Alkynes on hydration in the presence of H2SO4 and HgSO4 yield carbonyl compounds through enolAll alkynes except ethyne give ketones while ethyne gives aldehyde.
Why the other options are wrong
- A. CnH2n+2 is the formula of an alkane
- B. CnH2n is formula of alkene
- D. This is incorrect.
Q104. Consider reversibility in free radical substitution reaction of alkane then Kc value is smallest for:
- A. Initiation step
- B. Propagation step
- C. Termination step✓
- D. All same
Explanation: In a free radical substitution reaction of an alkane, the reaction can proceed through several steps involving free radicals (species with unpaired electrons). For this type of reaction, reversibility is more likely to occur in the termination step.The termination step involves the combination of two free radicals, leading to the formation of a stable molecule. This step can be reversible in certain cases, resulting in the reformation of free radicals. For example:Initiation step: Formation of free radicals (R·) by the homolytic cleavage of a bond in the alkane due to the presence of an initiator (e.g., light or heat). Propagation steps: Free radicals react with the alkane to form new free radicals and alkyl radicals, continuing the chain reaction.Termination step: Two free radicals combine to form a stable molecule.Since the termination step involves the recombination of free radicals and is less likely to be fully irreversible, the equilibrium constant (Kc) for this step would likely be smaller compared to the propagation steps, which involve the generation of new free radicals.It's important to note that the overall reaction is usually considered irreversible, but individual steps within the reaction mechanism may exhibit different degrees of reversibility. The termination step is generally considered to have a smaller Kc value due to its potential for reversibility.
Why the other options are wrong
- A. Initiation step: Kc = [Cl°] [Cl°] / [Cl2] Kc > 1
- B. Propagation step Kc = [HCl] [CH3°] / [CH4] [Cl°] Kc =1
- D. As per the explanation, termination step has smallest Kc.
Q105. SiO2 is the only oxide that reacts with:
- A. HClaq
- B. KOHaq✓
- C. Steam
- D. SO3
Explanation: SiO2 is an acidic oxide and reacts with strong bases. Among the given options, it will react with hot, concentrated KOH(aq) due to the need for strong conditions to overcome its extensive covalent bonding. It does not react with HCl(aq) because it is not a base. It doesn't react with steam as the strong covalent network structure of SiO2 is too stable to break under such conditions. Lastly, SO3 is also an acidic oxide, and thus, does not react with another acidic oxide like SiO2.
Why the other options are wrong
- A. SiO2 is not basic and does not react with acids like HCl, as it lacks oxide ions.
- C. SiO2 does not react with steam because its covalent network structure does not break easily.
- D. Both SiO2 and SO3 are acidic, hence they do not react with each other.
Q106. Students were heating CaCO3 in an open container to produce CO2 gas,CaCO3(s) ⟶ CaO(s) + CO2(g)If we increase pressure on this system the:
- A. Equilibrium will shift towards right
- B. Equilibrium will shift towards left
- C. Equilibrium will not be disturbed
- D. System does not obey equilibrium rules✓
Explanation: The correct answer is that the system does not obey equilibrium rules. Chemical equilibrium can only be established in a closed system where reactants and products are contained. In this scenario, the CaCO3 is heated in an open container, allowing the CO2 gas to escape. As a result, the system cannot reach equilibrium, as the continuous loss of CO2 gas prevents the establishment of a dynamic balance between reactants and products.All other options are incorrect because they assume that equilibrium can be achieved or disturbed in an open system, which is not possible. The nature of an open system prevents the maintenance of chemical equilibrium as it allows mass to be lost to the surroundings.
Why the other options are wrong
- A. This option is incorrect because the system is open, and equilibrium cannot be established. In an open system, the gas produced leaves the system, preventing the establishment of equilibrium.
- B. This option is incorrect because the system is open, and equilibrium cannot be established. Changes in pressure do not affect an open system in the same way as a closed system.
- C. This option is incorrect because in an open system, equilibrium cannot be reached in the first place. Since the system is open, any product formed escapes, and equilibrium cannot be maintained.
Q107. Initially one mole each N2 and O2 were made to react as,If at equilibrium 0 ∙ 25 moles of O2 is present the equilibrium concentration of NO will be:
- A. 0.50 moles
- B. 0.125 moles
- C. 1.50 moles✓
- D. 1.75 moles
Explanation: N2(g) + O2(g) 2NO(g) As from the balance chemical equation it is clear that 1 mole O2 gives 2 mole NO so as 0.25 mole O2 left so 0.75 mole consumed so it will give 1.50 mole NO.2x0.75-1=1.50
Why the other options are wrong
- A. This option is incorrect. According to the balanced chemical equation N2(g) + O2(g) → 2NO(g), each mole of O2 consumed yields 2 moles of NO. If 0.75 moles of O2 are consumed, 1.50 moles of NO should form, not 0.50 moles.
- B. This option is incorrect. The stoichiometry of the reaction implies that 0.75 moles of O2 consumption would yield 1.50 moles of NO. 0.125 moles is too low.
- D. This option is incorrect. The reaction stoichiometry dictates that 0.75 moles of O2 consumed would produce exactly 1.50 moles of NO, not 1.75 moles.
Q108. The type of isomerism present in the compound given, is:
- A. Structural
- B. Optical
- C. Stereo✓
- D. None of the above
Explanation: Stereoisomers are isomers that have the same composition (that is, the same parts) but that differ in the orientation of those parts in space. There are two kinds of stereoisomers: enantiomers and diastereomers. The two conditions must be met for compounds to show Stereoisomerism(geometric isomerism) 1- There should be a C-C double bond to restrict the free rotation of attached groups.2- The two groups attached to the same C must be different.
Why the other options are wrong
- A. Structural isomers, also known as constitutional isomers, have the same molecular formula but differ in the connectivity of atoms within the molecules.
- B. Optical isomerism occurs when isomers have the same molecular formula and structural formula but differ in their effect on plane-polarized light, typically due to chiral centers.
- D. This option implies that none of the given types of isomerism are correct, which is not true in this context as stereoisomerism is applicable.
Q109. The volume of 𝐶𝑂2 produced by heating 33.5𝑔 𝐿𝑖2𝐶𝑂3 at room temperature and pressure is (𝑀𝑟 𝐿𝑖2𝐶𝑂3 = 67𝑔/𝑚𝑜𝑙):
- A. 22.4 𝑑𝑚3
- B. 12.0 𝑑𝑚3✓
- C. 11.2 𝑑𝑚3
- D. 24.0 𝑑𝑚3
Explanation: moles of Li2CO3= mass/Mr =33.5/67 = 0.5 Moles of CO2: moles of Li2CO3 1 : 1Hence moles of CO2 =0.5 0.5 × 24= 12dm3 Molar volume at ROOM temperature and pressure is 12 dm³ while molar volume at STANDARD temperature and pressure is 22.4 dm³.
Why the other options are wrong
- A. This option assumes the use of standard temperature and pressure (STP) conditions, where the molar volume is 22.4 dm³. However, the problem specifies room temperature and pressure, where the molar volume is 24 dm³.
- C. This option incorrectly assumes a molar volume different from room temperature conditions or an incorrect mole calculation.
- D. This option assumes that 1 mole of CO2 is produced, but only 0.5 moles of Li2CO3 are heated, producing only 0.5 moles of CO2.
Q110. The compound which can form hydrogen bond with water is:
- A. CH3–O-CH3
- B. CH3 –CH2 –OH✓
- C. CH3 –CH2–NH2
- D. None of the above.
Explanation: Option B contains OH that can interact with the water to form a hydrogen bond with water. Hydrogen bonding occurs when hydrogen has a covalent bond to an atom that is more electronegative than it. The more electronegative atom pulls the shared electrons unequally towards it, creating a polar bond.
Why the other options are wrong
- A. Option A) CH3-O-CH3 (dimethyl ether) and option C) CH3-CH2-NH2 (ethylamine) do not have a hydrogen bond-donating group that can interact with water via hydrogen bonding.
- C. Option A) CH3-O-CH3 (dimethyl ether) and option C) CH3-CH2-NH2 (ethylamine) do not have a hydrogen bond-donating group that can interact with water via hydrogen bonding.
- D. This option is incorrect as option b is correct.
Q111. Choose the molecule that could not be represented by single electronic structure formula:
- A. CH4
- B. H2O
- C. SO2✓
- D. O2
Explanation: C is the correct option as the electronic structure of the SO2 molecule is best represented as a resonance hybrid of two equivalent structures.
Why the other options are wrong
- A. CH4 can be represented by a single electronic structure formula, which is a tetrahedral structure with four covalent bonds between carbon and hydrogen atoms.
- B. Water (H2O) can be represented by a single Lewis structure with one oxygen atom double-bonded to two hydrogen atoms. The two lone pairs of electrons on the oxygen atom occupy two other orbitals.
- D. O2 requires multiple resonance structures to represent its true electronic structure.
Q112. The shape of SnCl2 is:
- A. Linear
- B. Tetrahedral
- C. Angular✓
- D. Trigonal Planar
Explanation: SnCl2 (Tin dichloride) has a bent or V-shaped geometry, which is an example of an angular or non-linear shape. The molecule has a central tin atom that is bonded to two chlorine atoms. The two bond pairs of electrons repel each other, resulting in a bent shape. The bond angle is approximately 119 degrees. This bent shape is due to the lone pair of electrons present on the tin atom. The lone pair occupies a greater amount of space compared to the bond pair, resulting in the distortion of the molecule. In contrast, the linear shape is a molecular geometry in which the atoms of the molecule are arranged in a straight line, like in HCl or CO2. Tetrahedral shape is a molecular geometry that has four atoms attached to a central atom, like in CH4 or CCl4. Trigonal shape is a molecular geometry that has three atoms attached to a central atom, like in BF3.
Why the other options are wrong
- A. Linear: A linear shape would require the two chlorine atoms to be 180 degrees apart, which would only happen if there were no lone pair on tin. The lone pair's presence forces the molecule to bend.
- B. Tetrahedral: A tetrahedral shape requires four electron groups around the central atom. SnCl2 only has three (two bonds, one lone pair).
- D. Trigonal Planar: While the electron group geometry is based on trigonal planar, the molecular shape is different due to the lone pair's influence. If the lone pair's repulsion didn't alter the shape, then trigonal planar would be correct. However, it does, making the molecule bent.
Q113. Stable electronic configuration of Cu(29) is:
- A. [Ar] 4S2 3d4
- B. [Ar] 4S0 3d10
- C. [Ar] 4S1 3d10✓
- D. [Ar] 4S2 3d7 4p2
Explanation: It is a transition element. Copper (Cu) is a chemical element, a reddish, extremely ductile metal of Group 11 (IB) of the periodic table that is an unusually good conductor of electricity and heat. Due to the interelectronic repulsions one electron present in 4s enters to 3d subshell. We can write a stable electronic configuration of copper is written as 1s22s22p63s23p63d104s1. There is additional stability because of the completely occupied 3d subshell and half-filled 4s subshell.orThe electronic configurations of copper (and chromium) are unique since without filling the 4s orbitals, electrons entered into 3-d orbitals. Copper has an atomic number of 29 hence 29 electrons are fulfilled by option C as well.
Why the other options are wrong
- A. This configuration suggests that Copper (Cu) has the electron configuration [Ar] 4S^2 3d^4. However, this is not the stable electronic configuration of Copper. Copper has 29 electrons, and its stable electronic configuration is not with 3d^4.
- B. This configuration suggests that Copper has the electron configuration [Ar] 4S^0 3d^10. Again, this is not the stable electronic configuration of Copper. Copper has 29 electrons, and its stable electronic configuration is not with 3d^10.
- D. Incorrect option as per electronic configuration rules for transportation elements.
Q114. The proton acceptor is:
- A. NH3✓
- B. BF3
- C. HCl
- D. H+
Explanation: According to the Bronsted-Lowry theory, a base is a substance that accepts protons. NH3 is a classic example of a weak base that acts as a proton acceptor. In water, it reacts to form NH4+ and OH- ions, demonstrating its ability to accept a proton. In contrast, BF3 is a Lewis acid that accepts electron pairs, not protons. HCl is a proton donor, releasing H+ ions in water, and is therefore classified as an acid. Lastly, H+ is already a proton, so it cannot act as a proton acceptor.
Why the other options are wrong
- B. Incorrect. BF3 is an electron-deficient molecule and acts as a Lewis acid, meaning it accepts electron pairs rather than protons. Therefore, it is not a proton acceptor.
- C. Incorrect. HCl is a proton donor, not a proton acceptor. It dissociates in water to release H+ ions, thus acting as a Bronsted-Lowry acid.
- D. Incorrect. H+ itself is a proton and cannot accept another proton. It is typically accepted by bases.
Q115. Select alkene of the following hydrocarbons:
- A. C5 H22
- B. C5 H10✓
- C. C5 H8
- D. C4 H10
Explanation: The general formula for alkenes is CnH2n, where n=5 is the formula for alkene C5H10
Why the other options are wrong
- A. It is not the general formula of alkene.
- C. This is not the formula of alkene.
- D. It is the formula of alkane. Alkanes have the general formula of CnH2n+2 where n is the number of carbon atoms.
Q116. The oxidation state of carbon in Na2C2 is:
- A. +4
- B. +2
- C. –1✓
- D. –4
Explanation: We know that the charge of Na is always +1, and the overall charge on the Na2C2 molecule is 0. We can equate this to form2(+1) + 2x = 02x = -2x(Charge on C) = -1
Why the other options are wrong
- A. The oxidation state of carbon in Na2C2 is not +4.
- B. The oxidation state of carbon in Na2C2 is not +2.
- D. The oxidation state of carbon in Na2C2 is not -4.
Q117. Choose atom that having spin quantum number ½
- A. 12C
- B. 15N✓
- C. 16O
- D. 32S
Explanation: The spin is a quality of particles, it tells us the angular momentum (½) of an electron of a substance. Since momentum is a vector quantity, the spin quantum number can be both positive and negative. This question asks which atom has a ½ spin number, the positive and negative spins of atoms with an even number of electrons will cancel out, thus only an atom with an odd number of electrons has a spin of ½ which is B.
Why the other options are wrong
- A. The carbon-12 isotope, denoted as 12C, is the most common isotope of carbon. However, it does not have an unpaired electron and does not exhibit spin since all of its electrons are paired. Therefore, it does not have a spin quantum number of 1/2.
- C. The oxygen-16 isotope, denoted as 16O, contains eight protons and eight neutrons. It has a total of eight electrons. To determine if it has a spin quantum number of 1/2, we need to check if there are any unpaired electrons.The electron configuration of oxygen (O) is 1s2 2s2 2p4. It has two unpaired electrons in its 2p subshell (2px and 2py orbitals), and each of these electrons can have a spin of +1/2 or -1/2. Therefore, oxygen (16O) does have an electron with a spin quantum number of 1/2.
- D. The sulfur-32 isotope, denoted as 32S, contains 16 protons and 16 neutrons. It has a total of 16 electrons. To determine if it has a spin quantum number of 1/2, we need to check if there are any unpaired electrons.The electron configuration of sulfur (S) is 1s^2 2s2 2p6 3s2 3p4. It has four unpaired electrons in its 3p subshell (3px, 3py, and 3pz orbitals), and each of these electrons can have a spin of +1/2 or -1/2. Therefore, sulfur (32S) does have electrons with a spin quantum number of 1/2.
Q118. A tertiary carbon is bonded directly to:
- A. 2 Hydrogens
- B. 2 Carbons
- C. 3 Carbons✓
- D. 4 Carbons
Explanation: A tertiary carbon is a carbon atom bonded directly to three other carbon atoms. This classification helps in understanding the structure and reactivity of hydrocarbons. The correct option is Option C: 3 Carbons. Other options are incorrect as they either involve fewer carbon atoms or incorrectly include hydrogen atoms, which do not change the classification of the carbon atom in this context. Option D is incorrect as it describes a quaternary carbon, which is bonded to four carbon atoms.
Why the other options are wrong
- A. Incorrect. A tertiary carbon is bonded to three other carbon atoms, not hydrogen atoms.
- B. Incorrect. A tertiary carbon must be bonded to three other carbon atoms.
- D. Incorrect. A carbon atom bonded to four other carbon atoms would be a quaternary carbon, not tertiary.
Q119. Which of the following compounds will react with methyl magnesium Iodide followed by acid hydrolysis to give ethyl alcohol?
- A. Ethylene
- B. Acetone
- C. Acetaldehyde
- D. Formaldehyde✓
Explanation: When formaldehyde (CH2O) reacts with methyl magnesium iodide (CH3MgI), followed by acid hydrolysis, it gives ethyl alcohol (ethanol). The Grignard reagent reacts with the formaldehyde carbonyl group, forming a compound that can be hydrolyzed to yield ethyl alcohol.The reaction can be represented as follows:CH2O + CH3MgI → CH3CH2OH
Why the other options are wrong
- A. Ethylene, being an unsaturated hydrocarbon without a carbonyl group, cannot react with a Grignard reagent to form an alcohol. Grignard reagents require a carbonyl group to initiate the reaction.
- B. Acetone, a ketone, reacts with a Grignard reagent to form a tertiary alcohol, not ethyl alcohol. The carbonyl carbon of acetone is attacked by the Grignard reagent, leading to a different alcohol structure.
- C. Acetaldehyde, an aldehyde, would react with methyl magnesium iodide to form a secondary alcohol. However, this does not match the desired ethyl alcohol product specified in the question.
Q120. Which of the following compounds does not give iodoform test on reaction with I2 and NaOH?
- A. Propanone
- B. Ethanol
- C. Butanone
- D. Methanol✓
Explanation: It does not have methyl group attached to alpha carbon so it will not give idoform test
Why the other options are wrong
- A. Propanone, also known as acetone, contains a methyl ketone group, which reacts with I2 and NaOH to give a positive iodoform test.
- B. Ethanol contains the CH3CH(OH)- group, which upon oxidation forms acetaldehyde, giving a positive iodoform test.
- C. Butanone also contains a methyl ketone group, enabling it to produce a positive iodoform test.
Q121. Which of the following substitutents is an Ortho and Para director and ring deactivating?
- A. –OH
- B. –NH2
- C. –Cl✓
- D. –OCH3
Explanation: In electrophilic aromatic substitution, the nature of the substituent on the benzene ring plays a crucial role in determining the position of new substituents and the reactivity of the ring. Ortho-para directors are groups that direct incoming electrophiles to the 2, 4 (ortho, para) positions. While most ortho-para directors are activating, -Cl is an exception as it directs due to resonance but deactivates due to a strong inductive effect. This means it reduces the overall reactivity of the benzene ring but still allows for substitution at ortho and para positions.In contrast, –OH and –NH2 groups are strong activators, and –OCH3 is moderately activating; all increase the reactivity of the benzene ring and direct electrophiles to ortho and para positions without deactivating the ring.
Why the other options are wrong
- A. The –OH group is an activator due to its electron-donating resonance effect, making the benzene ring more reactive. It directs incoming groups to the ortho and para positions, but it is not deactivating.
- B. The –NH2 group is a strong activator and an ortho-para director due to its electron-donating resonance effect. It increases the electron density of the benzene ring, making it not deactivating.
- D. The –OCH3 group is an activating group due to its electron-donating resonance effect, leading to increased reactivity of the benzene ring. It is an ortho-para director but not deactivating.
Q122. Which of the following compounds undergo nitration most readily?
- A. Benzene
- B. Toluene✓
- C. Benzoic acid
- D. Nitrobenzene
Explanation: The correct answer is Toluene. Toluene undergoes nitration much faster than benzene due to the presence of a methyl group. This group donates electron density to the ring, particularly enhancing the reactivity at the ortho and para positions, making the electrophilic aromatic substitution process more favorable.Why the other options are incorrect:Benzene: While benzene can undergo nitration, it lacks activating groups, making it less reactive compared to toluene.Benzoic Acid: The carboxyl group is a deactivating group, reducing electron density in the ring and hindering electrophilic attack.Nitrobenzene: The nitro group is a strong deactivator, making further nitration extremely difficult due to the electron-deficient ring.
Why the other options are wrong
- A. Benzene can undergo nitration but does so at a slower rate compared to compounds with electron-donating groups. Its lack of substituents makes it less reactive in electrophilic aromatic substitution reactions.
- C. Benzoic acid contains a carboxyl group, which is a deactivating group. This group pulls electron density away from the benzene ring, reducing its reactivity towards electrophilic substitution reactions like nitration.
- D. Nitrobenzene already has a nitro group, which is a strongly deactivating group, making the ring electron-deficient. This significantly reduces its ability to undergo further nitration.
Q123. Which one of the following is most ionic?
- A. NaCl
- B. MgCl2
- C. KCl✓
- D. AlCl3
Explanation: The correct answer is KCl because it forms the most ionic bond among the options provided. Potassium (K) is larger and has a lower charge density than sodium (Na), making it easier to lose its valence electron and form a K+ cation. According to Fajan's rules, larger cations with a lower charge density form more ionic bonds, which is why KCl is more ionic than NaCl. NaCl is ionic, but sodium's smaller size compared to potassium leads to a slightly higher charge density, resulting in less ionic character compared to KCl.MgCl2 has a +2 charge on magnesium, which increases the covalent character of the bond due to polarization effects.AlCl3 is more covalent due to aluminum's +3 charge, which causes significant polarization of the chloride ions. The ability of AlCl3 to form a dimer also supports its covalent nature.
Why the other options are wrong
- A. Sodium chloride (NaCl) is a classic example of an ionic compound. Sodium (Na) loses one electron to form a Na+ cation, and chlorine (Cl) gains an electron to form a Cl- anion, resulting in a strong ionic bond. However, NaCl is less ionic than KCl because sodium is smaller and has a slightly higher charge density than potassium.
- B. Magnesium chloride (MgCl2) involves magnesium (Mg) losing two electrons to form a Mg2+ cation. The +2 charge on magnesium increases the covalent character of the bond compared to compounds with +1 cations like KCl and NaCl.
- D. Aluminum chloride (AlCl3) is less ionic and more covalent in nature. Aluminum (Al) forms a +3 charge, which polarizes the chloride ions, increasing the covalent character. Additionally, AlCl3 can form a dimer (Al2Cl6), further indicating its covalent nature.
Q124. Rain water becomes acidic, when the pH-value of rain water becomes _
- A. Greater than 6
- B. Greater than 6.5
- C. Less than 5.6
- D. Less than 5✓
Explanation: Normal clean rain has a pH value between 5.0 - 5.5, which is slightly acidic, however when rain combines with nitrogen oxides or SO2, it becomes more acidic has the pH drops below 5.0. Therefore the answer is D.
Why the other options are wrong
- A. a) Greater than 6:This option suggests that rainwater becomes acidic when the pH-value of rainwater becomes greater than 6. This statement is not correct. A pH value greater than 6 indicates that the rainwater is still slightly acidic but not to the extent of being a concern for acidity.
- B. b) Greater than 6.5:This option states that rainwater becomes acidic when the pH-value of rainwater becomes greater than 6.5. This statement is not correct. A pH value greater than 6.5 is in the neutral to slightly alkaline range, and it does not indicate acidic rainwater.
- C. c) Less than 5.6:This option suggests that rainwater becomes acidic when the pH-value of rainwater becomes less than 5.6. This statement is partially correct. Rainwater is considered acidic when its pH falls below 5.6. This can happen due to the dissolution of atmospheric pollutants such as sulfur dioxide (SO2) and nitrogen oxides (NOx), which combine with water vapor in the atmosphere to form sulfuric acid (H2SO4) and nitric acid (HNO3). These acidic compounds lower the pH of rainwater, making it acidic.
Q125. How many molecules are present in 0.20 g of Hydrogen gas? Select the correct option.
- A. 0.20 x 3.01 x 1023✓
- B. 0.20 x 2.016
- C. 0.70 x 6.02 x 1023
- D. 1.008 x 6.02 x 1023
Explanation: To find the number of molecules in 0.20 g of hydrogen gas, first recognize that hydrogen gas (H2) is diatomic. This means that 1 mole of hydrogen gas, which weighs 2.016 g, contains 6.02 x 1023 molecules. Therefore, 1 g of hydrogen gas contains 3.01 x 1023 molecules. To find the number of molecules in 0.20 g, multiply 0.20 by 3.01 x 1023, yielding 0.20 x 3.01 x 1023 molecules.Option A correctly uses this method. Option B fails by using the molar mass without Avogadro's number, Option C uses an incorrect proportion, and Option D uses the atomic mass of hydrogen instead of the diatomic gas.
Why the other options are wrong
- B. This option is incorrect because it does not account for Avogadro's number and is instead using the molar mass of H2 incorrectly.
- C. This option is incorrect because the multiplier (0.70) does not reflect the correct mass proportion of hydrogen used in this problem.
- D. This option is incorrect as it uses the atomic mass of hydrogen (1.008) without considering the diatomic nature of hydrogen gas.
Q126. Which of following functional groups are deactivating and not ortho, para directing?
- A. –R
- B. –COR✓
- C. –NH2
- D. NR2
Explanation: Ortho and para directing grps release electrons to the benzene ring increasing the chemical reactivity of the benzene ring towards electrophiles. Meanwhile meta directing grps withdraw the electrons from the benzene ring towards themselves decreasing their availability towards electrophiles. Therefore the answer will be B.
Why the other options are wrong
- A. a) –R:The functional group –R represents an alkyl group, which is a hydrocarbon chain. Alkyl groups are generally weakly deactivating and not ortho, para directing in electrophilic aromatic substitution reactions. Alkyl groups have a slightly electron-donating effect due to the release of electron density through hyperconjugation. However, their effect is not strong enough to significantly activate the benzene ring toward electrophilic substitution, and they do not direct incoming substituents to the ortho and para positions.
- C. c) –NH2:The functional group –NH2 represents an amino group, which is weakly activating and ortho, para directing in electrophilic aromatic substitution reactions. The amino group has a lone pair of electrons that can donate electron density to the benzene ring through resonance, making the ring more reactive toward electrophiles. Moreover, the amino group directs incoming substituents to the ortho and para positions.
- D. d) –NR2:The functional group –NR2 represents a secondary amine group, where R can be an alkyl or aryl group. Secondary amine groups are weakly activating and ortho, para directing in electrophilic aromatic substitution reactions. Similar to the –NH2 group, the lone pair of electrons on the nitrogen atom can donate electron density to the benzene ring through resonance, making it more reactive toward electrophiles. Also, the –NR2 group directs incoming substituents to the ortho and para positions.
Q127. Which one of the following is strongest acid?
- A. CH3COOH
- B. CH3CH2COOH
- C. C6H5CG2COOH
- D. FCH2COOH✓
Explanation: D is the correct option, as it contains a halogen which have strong electron-withdrawing effects.
Why the other options are wrong
- A. a) CH3COOH (Acetic acid):This is acetic acid, also known as ethanoic acid. It is a weak acid, and its acidity is derived from the dissociation of the hydrogen ion (H+) from the carboxyl group (–COOH). It partially dissociates in water to form H3O+ and CH3COO- ions. Acetic acid is commonly found in vinegar.
- B. b) CH3CH2COOH (Propanoic acid):This is propanoic acid. It is also a weak acid, similar to acetic acid. Propanoic acid is derived from the dissociation of the hydrogen ion (H+) from the carboxyl group (–COOH). It partially dissociates in water to form H3O+ and CH3CH2COO- ions.
- C. c) C6H5CG2COOH (Benzoic acid):This is benzoic acid, which contains a phenyl group (C6H5) attached to the carboxyl group (–COOH). Benzoic acid is a weak acid, but it is slightly stronger than acetic and propanoic acids due to the electron-withdrawing effect of the phenyl group, which stabilizes the resulting carboxylate ion after dissociation.
Q128. Which of the following structure has a bond formed by an overlap of sp2 hybrid orbital with that of sp2 hybrid orbital?
- A. HC = CH
- B. H2C = CH2✓
- C. H2C = C= CH2
- D. CH2= CHCH3
Explanation: The C-C sigma bond in ethylene is formed by the overlap of an sp2 hybrid orbital from each carbon. The overlap of hybrid orbitals or a hybrid orbital and a 1s orbtial from hydrogen creates the sigma bond framework of the ethylene molecule.
Why the other options are wrong
- A. a) HC = CH:This structure represents ethyne, also known as acetylene. It consists of two carbon atoms triple-bonded to each other. The carbon atoms in ethyne are sp hybridized, but there is no overlap with an sp2 hybrid orbital in this molecule. Therefore, option a) is not the correct answer.
- C. c) H2C = C= CH2:This structure represents allene, also known as propadiene. It consists of three carbon atoms with the two terminal carbon atoms double-bonded to the central carbon. The terminal carbon atoms in allene are sp hybridized, and there is an overlap of sp hybrid orbitals with sp2 hybrid orbitals from the central carbon to form the double bonds.
- D. d) CH2 = CHCH3:This structure represents 2-methylpropene. It consists of three carbon atoms with a double bond between the first and second carbon atoms. The first carbon atom is sp2 hybridized, and the second carbon atom is sp3 hybridized, but there is no overlap of an sp2 hybrid orbital with an sp hybrid orbital in this molecule. Therefore, option d) is not the correct answer.
Q129. The bond angle between H-C-H bond in ethane is:
- A. 109.5✓
- B. 120
- C. 90
- D. 107.5
Explanation: Ethane, C2H6, has a geometry related to that of methane. The two carbons are bonded together, and each is bonded to three hydrogens. Each H-C-H angle is 109.5° and each H-C-C angle is 109.5°.
Why the other options are wrong
- B. b) 120 degrees:This bond angle is characteristic of trigonal planar geometry, which is found in molecules with sp2 hybridization. However, ethane does not have a bond angle of 120 degrees. Trigonal planar geometry is not applicable to ethane's structure.
- C. c) 90 degrees:This bond angle is characteristic of molecules with sp hybridization. However, ethane does not have a bond angle of 90 degrees. Ethane consists of sigma (σ) bonds between the carbon atoms and hydrogen atoms, but its geometry is not linear.
- D. This option is incorrect.In Ethane, carbon shows SP3 hybridization and tetrahedral geometry.In this geometry, carbon is present in the center with 4 hydrogen atoms at the corners of a regular tetrahedron. Thus it shows a bond angle of 109.5.
Q130. Which is the correct product formed when monohydric alcohol reacts with sodium metal?
- A. Alkene
- B. Sodum alkoxide✓
- C. Alkane
- D. Ether
Explanation: When alcohols react with metals a salt is formed,the reaction when a monohydric alcohol reacts with sodium metal results in the production of sodium alkoxide and hydrogen gas, hence the answer is B.
Why the other options are wrong
- A. a) Alkene: The reaction between a monohydric alcohol and sodium metal does not directly lead to the formation of an alkene (a compound with a carbon-carbon double bond). The given reaction produces sodium alkoxide and hydrogen gas.
- C. c) Alkane: The reaction between a monohydric alcohol and sodium metal does not lead to the formation of an alkane (a compound with only single carbon-carbon bonds). Instead, the product is sodium alkoxide.
- D. d) Ether: The reaction between a monohydric alcohol and sodium metal does not directly produce an ether (a compound with an oxygen atom bonded to two alkyl or aryl groups). The correct product is sodium alkoxide.
Q131. Thermal processing of industrial waste material aims at:
- A. Burning of waste material in pits
- B. Converting the solid waste into useful products by thermal treatment✓
- C. Energy recovery from organic matter prior to its final disposal
- D. Size reduction and compaction by thermal process
Explanation: The primary function of thermal treatment is to convert the waste to a stable and usable end product. Therefore the answer will be B.
Why the other options are wrong
- A. a) Burning of waste material in pits:This option refers to open burning of waste material in pits, which is not an appropriate method of thermal processing for industrial waste. Open burning can lead to air pollution and the release of harmful gases and particulate matter, which can have negative environmental and health impacts.
- C. c) Energy recovery from organic matter prior to its final disposal:This option also describes a valid objective of thermal processing. Many industrial waste materials contain organic matter that can be converted into energy through processes like anaerobic digestion or incineration. The aim is to recover energy from the waste before its final disposal, reducing the environmental impact and maximizing resource utilization.
- D. d) Size reduction and compaction by thermal process:While thermal processing can lead to size reduction and compaction of certain waste materials, this is not the primary objective of thermal treatment for industrial waste. Size reduction and compaction are often achieved through mechanical methods, such as shredding or compacting machines, rather than solely relying on thermal processes.
Q132. Which of the following titrants would most likely be used as ths‘ own indicator in acid medium?
- A. K2Cr2O7 (Potassium dichromate)
- B. Iodine (I2)
- C. KMnO4 (Potassium permanganate)✓
- D. H2O2 (Hydrogen peroxide)
Explanation: Potassium permanganate (KMnO4) is used as its own indicator because it changes color distinctly at the endpoint of a titration in an acidic medium. The intense purple color of KMnO4 fades to colorless (or a very faint pink) as it is reduced, providing a clear visual cue without the need for an additional indicator. In contrast, K2Cr2O7, Iodine, and H2O2 lack such a distinct color change when used in acidic conditions, making them unsuitable as self-indicators.
Why the other options are wrong
- A. K2Cr2O7 is a powerful oxidizing agent but does not serve as its own indicator in acid medium since it does not show a distinct color change upon reaction completion.
- B. Iodine does not serve as its own indicator in acid medium as it lacks a distinct color change at the endpoint and is typically used with starch as an indicator in iodometric titrations.
- D. H2O2 does not exhibit a visible color change in acid medium and is not used as its own indicator in titrations.
Q133. Chlorosis is caused by the deficiency of:
- A. Magnesium✓
- B. Iron
- C. Phosphorus
- D. Potassium
Explanation: Chlorosis is typically caused when leaves do not have enough nutrients to synthesise all the chlorophyll they need. It can be brought about by a combination of factors including: a specific mineral deficiency in the soil of Mg2+
Why the other options are wrong
- B. . Iron (Fe) Deficiency:Causes chlorosis (yellowing of young leaves) due to impaired chlorophyll synthesis.Stunted growth because iron is essential for enzyme activation and photosynthesis.Common in alkaline (high pH) soils.
- C. Phosphorus (P) Deficiency:Dark green or purplish leaves (due to anthocyanin accumulation).Stunted growth as phosphorus is crucial for ATP, DNA, and cell division.Poor root development, leading to weak plants.Delayed flowering and fruiting.
- D. Potassium (K) Deficiency:Yellowing and browning (necrosis) of leaf edges and tips.Weak stems and lodging (plants falling over).Reduced resistance to drought and diseases.Poor fruit and seed quality due to disrupted water and nutrient transport.
Q134. How many different values can m, assume in the electron sub-shell designated by quantum number n=5, l=4?
- A. 4
- B. 5
- C. 6
- D. 9✓
Explanation: 'n' is referred to as the principal quantum number and 'l' is the azimuthal quantum number. l=4 means the azimuthal quantum number is associated with 5g. Since 'g' has 9 subshells 'm' will be -4, -3, -2, -1, 0, +1, +2, +3, +4.
Why the other options are wrong
- A. a) 4:The magnetic quantum number (m) can take four different values: -4, -3, -2, -1, 0, +1, +2, +3, and +4. However, this option is not correct because there are nine different values that m can assume, not four.
- B. b) 5:The magnetic quantum number (m) can take five different values: -4, -3, -2, -1, 0, +1, +2, +3, and +4. This option is not correct because there are nine different values that m can assume, not five.
- C. c) 6:The magnetic quantum number (m) can take six different values: -4, -3, -2, -1, 0, +1, +2, +3, and +4. This option is not correct because there are nine different values that m can assume, not six.
Q135. Which one of the following salts will produce an alkaline solution when dissolved in water?
- A. NH4Cl
- B. NaNO3
- C. Na2CO3✓
- D. Na2SO4
Explanation: The correct answer is Na2CO3. Sodium carbonate forms an alkaline solution because it undergoes hydrolysis in water, releasing hydroxide ions (OH-) which increase the pH. In contrast:NH4Cl forms an acidic solution due to ammonium ions generating hydronium ions.NaNO3 remains neutral as neither ion affects pH significantly.Na2SO4 also results in a neutral solution for similar reasons to NaNO3.
Why the other options are wrong
- A. NH4Cl (Ammonium chloride) is an acidic salt. When dissolved in water, it releases ammonium ions (NH4+), which slightly acidify the solution by forming hydronium ions (H3O+).
- B. NaNO3 (Sodium nitrate) is a neutral salt. Its dissolution in water does not affect the pH significantly, as neither sodium ions (Na+) nor nitrate ions (NO3-) react with water to alter the pH.
- D. Na2SO4 (Sodium sulfate) is a neutral salt. Neither its sodium ions (Na+) nor sulfate ions (SO42-) significantly interact with water, resulting in a neutral solution.
Q136. In an inelastic collision, Momentum is _ and Kinetic Energy is _ respectively.
- A. Not conserved ; not conserved
- B. conserved ; not conserved✓
- C. Conserved ; conserved
- D. Not conserved ; conserved
Explanation: For elastic and inelastic collisions, momentum and total energy are always conserved provided no external force is applied; however, for inelastic collisions, kinetic energy is NOT conserved.
Why the other options are wrong
Q137. A bullet of mass 20g leaves the gun with a velocity of 200 m/s. If the mass of gun is 2kg then the speed of recoil of the gun is:
- A. 2000 m/s
- B. 2 m/s✓
- C. 20 m/s
- D. 200 m/s
- E. 100 m/s
Explanation: The principle of conservation of momentum states that the total momentum of an isolated system remains constant. Here, the gun and the bullet together form a system. So, the momentum of the gun and the bullet before firing will be equal to the momentum of the gun and the bullet after firing.Initial momentum = Final momentum(mass of gun) x (velocity of gun) = (mass of bullet) x (velocity of bullet) + (mass of gun) x (velocity of recoil)Substituting the values, we get:(2 kg) x 0 m/s = (0.02 kg) x (200 m/s) + (2 kg) x (velocity of recoil)Solving for the velocity of recoil, we get:velocity of recoil = - (0.02 kg) x (200 m/s) / (2 kg) = -2 m/sThe negative sign indicates that the recoil is in the opposite direction to the direction of the bullet. So, the magnitude of the speed of the recoil of the gun is 2 m/s.
Why the other options are wrong
- A. This option is incorrect. As mentioned earlier, the speed of the gun's recoil is not determined solely by the velocity of the bullet. The recoil speed depends on the conservation of momentum.
- C. This option is incorrect. The recoil speed of the gun will be much higher than 20 m/s. The momentum of the gun must equal the momentum of the bullet in the opposite direction.
- D. This option is incorrect. The recoil speed of the gun will be much higher than 200 m/s. The momentum of the gun must equal the momentum of the bullet in the opposite direction.
- E. This option is incorrect. The recoil speed of the gun will not be 100 m/s. The momentum of the gun must equal the momentum of the bullet in the opposite direction. Based on the given values, the recoil speed of the gun is determined to be 2 m/s, not 100 m/s.
Q138. A car at rest starts moving with linear uniformly increasing velocity. After 20 seconds, it attains the maximum velocity of 80 m/s. What is the distance covered during this time interval?
- A. 200 m
- B. 400 m
- C. 800 m✓
- D. 1600 m
Explanation: The acceleration of the car is constant as it undergoes uniformly increasing velocity. Let the initial velocity of the car be u = 0 m/s, and final velocity be v = 80 m/s. The time taken to achieve this velocity is t = 20 s.Using the formula for uniformly accelerated motion, we have:v = u + atwhere a is the acceleration. Rearranging the equation, we get:a = (v - u)/t = 80 m/s / 20 s = 4 m/s2To find the distance covered by the car during the given time interval, we use the formula:s = ut + (1/2)at2where s is the distance traveled. Substituting the given values, we get:s = (1/2)(4 m/s2)(20 s)2 = 800 mTherefore, the correct answer is C) 800 m.
Why the other options are wrong
- A. This option suggests that the distance covered during the time interval is 200 m. However, this is not correct based on the given information. The car starts from rest and reaches a maximum velocity of 80 m/s, which implies it has covered a greater distance.
- B. This option suggests that the distance covered during the time interval is 400 m. Similar to Option A, this value is not consistent with the given information. The car achieves a higher maximum velocity, so it would have covered a greater distance.
- D. This option suggests that the distance covered during the time interval is 1600 m. However, this is not correct based on the given information. The car reaches a maximum velocity of 80 m/s, which means it covers a shorter distance compared to 1600 m.
Q139. An object is thrown vertically upward with a velocity of 20 m/s. How much time it will take to reach the highest point?
- A. 2 sec✓
- B. 4 sec
- C. 1 sec
- D. Insufficient information
Explanation: Given: Initial velocity of object, u = 20 m/s Final velocity of object, v = 0 Acceleration, g = 10 m/s To find, 1. Distance travelled, s = ? 2. Time taken, t = ? Solution: 1. Distance travelled, s We know that, 3rd equation of motion, i.e v² - u² = 2(- g)s ⇒ (0)² - (20)² = 2 × (- 10) × s ⇒ 400 = 20s ⇒ 400/20 = s ⇒ s = 20 m Hence, the distance travelled by an object is 20 m. 2. Time taken, t We know that, 1st equation of motion i.e v = u + (- g)t= 20 + (- 10) × t 20 = 10t 20/10 = t ⇒ t = 2 seconds Hence, the time taken by the object is 2 seconds.
Why the other options are wrong
- B. Given:Initial velocity of object, u = 20 m/sFinal velocity of object, v = 0Acceleration, g = 10 m/sTo find,1. Distance travelled, s = ? 2. Time taken, t = ?Solution:1. Distance travelled, sWe know that,3rd equation of motion,i.e v² - u² = 2(- g)s⇒ (0)² - (20)² = 2 × (- 10) × s⇒ 400 = 20s⇒ 400/20 = s⇒ s = 20 mHence, the distance travelled by an object is 20 m. 2. Time taken, tWe know that,1st equation of motioni.e v = u + (- g)t= 20 + (- 10) × t20 = 10t 20/10 = t⇒ t = 2 secondsHence, the time taken by the object is 2 seconds.
- C. Given:Initial velocity of object, u = 20 m/sFinal velocity of object, v = 0Acceleration, g = 10 m/sTo find,1. Distance travelled, s = ? 2. Time taken, t = ?Solution:1. Distance travelled, sWe know that,3rd equation of motion,i.e v² - u² = 2(- g)s⇒ (0)² - (20)² = 2 × (- 10) × s⇒ 400 = 20s⇒ 400/20 = s⇒ s = 20 mHence, the distance travelled by an object is 20 m. 2. Time taken, tWe know that,1st equation of motioni.e v = u + (- g)t= 20 + (- 10) × t20 = 10t 20/10 = t⇒ t = 2 secondsHence, the time taken by the object is 2 seconds.
- D. Given:Initial velocity of object, u = 20 m/sFinal velocity of object, v = 0Acceleration, g = 10 m/sTo find,1. Distance travelled, s = ? 2. Time taken, t = ?Solution:1. Distance travelled, sWe know that,3rd equation of motion,i.e v² - u² = 2(- g)s⇒ (0)² - (20)² = 2 × (- 10) × s⇒ 400 = 20s⇒ 400/20 = s⇒ s = 20 mHence, the distance travelled by an object is 20 m. 2. Time taken, tWe know that,1st equation of motioni.e v = u + (- g)t= 20 + (- 10) × t20 = 10t 20/10 = t⇒ t = 2 secondsHence, the time taken by the object is 2 seconds.
Q140. An object is falling down with a speed of 20 m/s. After 3 secondsits velocity will be _ m/s (g = 10 m/s2).
- A. 05
- B. 50✓
- C. 55
- D. 95
Explanation: To find the final velocity of the object after 3 seconds of free fall, we use the kinematic equation: v = u + at. The initial velocity (u) is 20 m/s, the acceleration due to gravity (a) is 10 m/s2, and the time (t) is 3 seconds. Substituting these values into the equation, we get v = 20 + 10(3) = 20 + 30 = 50 m/s. Thus, the correct answer is 50 m/s. Option A (05) incorrectly assumes deceleration, Option C (55) miscalculates the velocity increase, and Option D (95) is an extreme overestimate.
Why the other options are wrong
- A. This option is incorrect. It suggests the object has decelerated, which contradicts the scenario where gravity is accelerating the object.
- C. This option is incorrect. It overestimates the increase in velocity by adding an extra 5 m/s.
- D. This option is incorrect. It vastly overestimates the increase in velocity, confusing the scenario with one involving much higher acceleration or initial velocity.
Q141. A paratrooper is falling down with uniform velocity and also rotating with a constant angular velocity of 0.2 rad/sec. The body satisfies _.
- A. The first condition of equilibrium but not the second
- B. The second condition of equilibrium but not the first
- C. Both the first and second conditions of equilibrium✓
- D. Neither the first nor the second condition of equilibrium
Explanation: The correct answer is Option C: Both the first and second conditions of equilibrium. The first condition of equilibrium states that the sum of all forces acting on an object must be zero for it to move with constant velocity; since the paratrooper is falling with uniform velocity, this condition is met. The second condition of equilibrium states that the sum of all torques acting on an object must also be zero for it to rotate with constant angular velocity; since the paratrooper is rotating with a constant angular velocity of 0.2 rad/sec, this condition is also satisfied. Options A and B are incorrect as they each claim that only one condition of equilibrium is satisfied while in fact, both are. Option D is also incorrect because it suggests that neither condition is satisfied, which contradicts the provided information about uniform velocity and constant angular velocity.
Why the other options are wrong
- A. This option suggests that while the translational forces are balanced, the rotational forces are not. However, since the paratrooper is rotating with a constant angular velocity, this implies that there is no net torque acting on the body, which means both conditions of equilibrium are satisfied.
- B. This option implies that while the rotational motion is in equilibrium, the translational motion is not. However, the paratrooper is falling with uniform velocity, indicating that translational forces are also balanced, thus this option is incorrect.
- D. This option suggests that neither translational nor rotational equilibrium is satisfied. However, the paratrooper is falling with uniform velocity and rotating with constant angular velocity, which indicates that both conditions are indeed satisfied, making this option incorrect.
Q142. A car of mass 1200 kg initially at rest has been accelerated to a speed of 8 m/s in 16 meters. Average acceleration of the car is _ m/s2? And force is _ N?
- A. 1.5 and 1500
- B. 2.5 and 2400
- C. 3.5 and 3500
- D. 2 and 2400✓
Explanation: To solve this problem, we start by determining the acceleration using the kinematic equation v² = u² + 2as, where:v is the final velocity (8 m/s),u is the initial velocity (0 m/s, since the car starts from rest),a is the acceleration, ands is the displacement (16 m).Substituting the known values into the equation:(8)² = (0)² + 2(a)(16)64 = 32aa = 2 m/s²Next, apply Newton's second law to find the force: F = ma.F = 1200 kg × 2 m/s² = 2400 NTherefore, the correct values are an acceleration of 2 m/s² and a force of 2400 N. The other options are incorrect because they do not satisfy both the acceleration and force calculations based on the given conditions.
Why the other options are wrong
- A. Incorrect. If you calculate the acceleration using the kinematic equation, 1.5 m/s² will not match the given conditions. Recalculating the force with this acceleration will also lead to an incorrect answer.
- B. Partially correct. The force is correct at 2400 N, but the acceleration of 2.5 m/s² is incorrect. Recalculate the acceleration using the equation of motion to verify.
- C. Incorrect. Both the acceleration and force values are incorrect. The acceleration does not match the conditions given, and therefore the force is also wrong.
Q143. A car starts from rest and moves with constant acceleration. During the 4th second of its motion, it covers a distance of 21 meters. The acceleration of the car is _ m.
- A. 04
- B. 06✓
- C. 08
- D. 16
Explanation: To determine the acceleration, utilize the formula for distance covered in the nth second of uniformly accelerated motion:Sn = u + ½ a (2n-1)Given:u = initial velocity = 0 m/s (as the car starts from rest)a = acceleration (unknown)n = 4 (since we are considering the 4th second)Sn = 21 metersSubstitute these values into the equation:21 = 0 + ½ × a × (2×4 - 1)21 = ½ × a × 742 = 7aTherefore, a = 6 m/s².The other options are incorrect due to errors in either substituting values into the formula or performing the calculations.
Why the other options are wrong
- A. This is incorrect. Double-check the formula used for calculating the distance covered in the nth second and ensure values are substituted correctly.
- C. This is incorrect. Re-evaluate your substitution into the formula and calculation for the acceleration.
- D. This is incorrect. This value is too high, indicating a mistake in either the formula application or arithmetic.
Q144. A wire of resistance 4 is bent into a circle. The resistance between the ends of a diameter of the circle is:
- A. 4Ω
- B. 1 Ω✓
- C. 1/4 Ω
- D. 1/16 Ω
Explanation: When a wire of resistance 4R is bent in the form of circle, then the resistance of each segment across the diameter becomes 2R.Equivalent resistance between A and B: +1/Rb (in parallel combination)∴ 1/RAB = 1/(2R) +1/(2R) 1/RAB = 2/(2R) ⟹ RAB=RHere is the link from where you understand this MCQ:
Why the other options are wrong
- A. This option is incorrect.
- C. This option is incorrect.
- D. This option is incorrect.
Q145. The state of thermal equllibrium between two systems is determined by equality of:
- A. Pressure
- B. Volume
- C. Temperature✓
- D. Mass
Explanation: Thermal equilibrium between two systems is determined by the equality of temperature, as stated by the Zeroth Law of Thermodynamics. This law implies that if no heat flows between the two systems, they are at the same temperature. Pressure and volume relate to mechanical and volumetric properties, respectively, but do not define thermal equilibrium. Mass influences heat capacity but is not a determining factor for thermal equilibrium.
Why the other options are wrong
- A. Pressure is related to mechanical equilibrium, not thermal equilibrium. It ensures that no net forces act on a system, but it does not determine thermal equilibrium.
- B. Volume can affect the capacity of a system to store heat, but it does not directly determine thermal equilibrium. Thermal equilibrium is not dependent on the volume being equal.
- D. Mass influences the amount of heat a system can absorb or release, but it does not determine thermal equilibrium. Equal mass does not imply thermal equilibrium.
Q146. Half cell reaction standard reduction potential, Eo=Fe2+ 2e- → Fe –0.41Cu2+ 2e- → Cu 0.34Ni2+ 2e- → Ni -0.25Zn2+ 2e- → Zn -0.76Referring to the table above which metal could be used to prevent iron from corrosion?
- A. Cu only
- B. Zn only✓
- C. Cu & Ni only
- D. Ni and Zn only
Explanation: The correct answer is Zn only. Zinc has a standard reduction potential of -0.76 V, which is more negative than iron's -0.41 V. This makes zinc an effective sacrificial anode, as it will oxidize before iron, thus protecting it from corrosion. Copper and nickel have higher (less negative) reduction potentials than iron, making them unsuitable for this purpose. Therefore, only zinc can provide the necessary protection.
Why the other options are wrong
- A. This option is incorrect. Copper has a less negative E0 value than iron, so it cannot be used to protect iron from corrosion.
- C. This option is incorrect. Neither copper nor nickel has a more negative E0 value than iron. Only zinc can act as a sacrificial anode for iron.
- D. This option is incorrect. While zinc can protect iron, nickel cannot since it does not have a more negative E0 value than iron.
Q147. If a wave can be polarized, it must be:
- A. An electromagnetic wave
- B. A stationary wave
- C. Transverse wave✓
- D. A longitudinal wave
Explanation: Transverse waves which include all electromagnetic waves such as light, radio waves, and x-rays can be polarized, hence the answer will be C.
Why the other options are wrong
- A. Transverse waves that include electromagnetic waves can be polarized.
- B. Stationary waves as the name said are stationary so polarization cannot differentiate them.
- D. Longitudinal waves are produced by compression and rarefaction of the medium that can pass through any type of polarizer.
Q148. In the nuclear reaction shown below what is the value of the coefficient?92U235+ 0n1_ = 56Kr89+γon1 + 200MeV
- A. 0
- B. 1
- C. 2
- D. 3✓
Explanation: In the fission reaction, uranium absorbs a neutron and forms a barium and krypton nucleus which are extremely unstable and they instantaneously release three neutrons between themselves becoming barium144 and krypton89, therefore the answer is option D.Option A is incorrect because a neutron is always produced in fission reactions. Option B is incorrect because fission reactions usually release around 2-3 neutrons, not just one. Option C is incorrect because the fission of U-235 typically releases 2 or 3 neutrons, not just two.
Why the other options are wrong
- A. A neutron is always produced to further undergo fission reaction
- B. When a nucleus fissions, it splits into several smaller fragments. These fragments, or fission products, are about equal to half the original mass. Approximately three neutrons are also emitted.
- C. A uranium-235 atom absorbs a neutron and fissions into two new atoms (fission fragments), releasing three new neutrons and some binding energy.
Q149. A racing car accelerates uniformly through three gear changes with the following average speeds:20 ms-1 for 2.0s ;40ms-1 for 2.0 s and 60 ms-1 for 6.0s. What is the overall average speed of the car?
- A. 12 ms-1
- B. 13.3 ms-1
- C. 40 ms-1
- D. 48 ms-1✓
Explanation: To find the overall average speed, we use the formula: Average speed = Total distance / Total time. First, calculate the individual distances traveled during each gear change:For the first gear change: Distance = 20 ms-1 x 2 s = 40 mFor the second gear change: Distance = 40 ms-1 x 2 s = 80 mFor the third gear change: Distance = 60 ms-1 x 6 s = 360 mThe total distance is 40 m + 80 m + 360 m = 480 m. The total time is 2 s + 2 s + 6 s = 10 s. Thus, the overall average speed is 480 m / 10 s = 48 ms-1, making Option D the correct answer.Options A, B, and C are incorrect because they do not correctly apply the formula for average speed, either due to incorrect calculations or by using incorrect values.
Why the other options are wrong
- A. This option is incorrect because it doesn't accurately reflect the calculation of total distance divided by total time.
- B. This option is incorrect. It seems to be a miscalculation of the average speed.
- C. This option is incorrect. It reflects one of the speeds during gear changes, not the overall average speed.
Q150. A generator produces 100 kW of power at a potential difference of 10KV. The power is transmitted through cables of total resistance 5Q. How much power is dissipated in the cables?
- A. 50 W
- B. 750 W
- C. 500 W✓
- D. 1000 W
Explanation: To find the power dissipated in the cables, you need to first calculate the current flowing through the circuit. The power produced by the generator is 100 kW, which is equal to 100,000 W, and the potential difference is 10 kV, equal to 10,000 V. Using the formula P = VI, where P is power, V is voltage, and I is current, you can solve for current:I = P / V = 100,000 W / 10,000 V = 10 A.Now, using the formula for power dissipation in the cables, P = I²R, where I is the current (10 A) and R is the resistance of the cables (5 ohms), you calculate:P = 10² x 5 = 100 x 5 = 500 W.Therefore, 500 W of power is dissipated in the cables.Options A (50 W), B (750 W), and D (1000 W) are incorrect as they do not result from the correct application of the power loss formula I²R with the calculated current.
Why the other options are wrong
- A. This calculation underestimates the power dissipation. Ensure you use the correct formula for power loss.
- B. This is incorrect as it does not result from the correct application of the power loss formula I²R.
- D. This option is incorrect as the calculation exceeds the actual power dissipation calculated by the formula I²R.
Q151. Ultraviolet rays differ from the X-rays such that ultraviolet rays _
- A. Cannot be diffracted
- B. Cannot be polarized
- C. Have a low frequency✓
- D. Do not affect a photographic plate
Explanation: Option C is correct
Why the other options are wrong
- A. Ultraviolet rays can indeed be diffracted, just like other electromagnetic waves. This statement is incorrect.
- B. All electromagnetic waves, including ultraviolet rays, can be polarized. Therefore, this option is also incorrect.
- D. This statement is incorrect; ultraviolet rays do affect photographic plates as they are sensitive to these rays, making this option false.
Q152. For transformer, if Ns/Nr = 2 : 1 then Ip/Is =
- A. 1:2
- B. 2:1✓
- C. 4:1
- D. 1:1
Explanation: Explanation is given below:
Why the other options are wrong
- A. This option is incorrect. Refer to the given explanation.
- C. This option is incorrect. Refer to the given explanation.
- D. This option is incorrect. Refer to the given explanation.
Q153. Astronomers calculate speed of distant stars and galaxies using which of the following phenomena:
- A. Beats
- B. Interference
- C. Superposition principle
- D. Doppler effect✓
Explanation: The Doppler effect is a phenomenon where the observed frequency of a wave changes depending on the relative motion between the source of the wave and the observer. This effect is commonly used in astronomy to determine the motion of celestial objects, such as stars and galaxies.In the context of astronomy, the most common application of the Doppler effect is the redshift or blueshift of light. When a celestial object is moving away from an observer, its light is shifted towards longer wavelengths (redshift), and when it is moving towards the observer, the light is shifted towards shorter wavelengths (blueshift).Astronomers can measure these shifts in the spectrum of light emitted by stars or galaxies to determine their radial velocity (motion along the line of sight). This information is crucial for understanding the dynamics of galaxies, the expansion of the universe, and other aspects of celestial motion and structure. The redshift of light from distant galaxies played a key role in the discovery of the expansion of the universe.
Why the other options are wrong
- A. Astronomers typically do not use beats to calculate the speed of distant stars and galaxies. Beats refer to the phenomenon that occurs when two waves with slightly different frequencies overlap, producing an oscillating pattern of alternating constructive and destructive interference.
- B. Interference is not commonly used by astronomers to calculate the speed of distant stars and galaxies. The primary method employed for determining the motion of celestial objects, especially those at vast distances, is the Doppler shift.
- C. The superposition principle is a fundamental concept in physics and wave theory, but it is not typically the primary method used by astronomers to calculate the speed of distant stars and galaxies. The superposition principle states that, in a linear medium, the net response at a given point caused by multiple independent waves is the sum of the responses that each wave would produce individually.
Q154. In a full-wave bridge rectification, the number of diodes used are:
- A. 1
- B. 2
- C. 3
- D. 4✓
Explanation: A full-wave bridge rectifier consists of 4 diodes arranged in a bridge configuration. This arrangement allows the rectifier to convert both halves of an AC waveform into a pulsating DC output. When the positive half-cycle of the AC input is applied, diodes D1 and D2 conduct, allowing current to flow through the load. During the negative half-cycle, diodes D3 and D4 conduct, again directing current through the load in the same direction. This ensures that the load always receives a unidirectional current. Options A, B, and C are incorrect because they do not provide the necessary number of diodes to achieve full-wave rectification in a bridge configuration.
Why the other options are wrong
- A. This is incorrect. A single diode cannot perform full-wave rectification.
- B. This is incorrect. Two diodes can be used in a center-tapped full-wave rectification, not a bridge rectifier.
- C. This is incorrect. Three diodes are insufficient for full-wave bridge rectification.
Q155. The number of diodes in bridge rectifier is:
- A. 4✓
- B. 3
- C. 2
- D. 5
Explanation: A bridge rectifier consists of 4 diodes arranged in a bridge configuration.Working of a Bridge Rectifier:The four diodes are connected in such a way that they convert AC (alternating current) to DC (direct current).During the positive half-cycle of the AC input, two diodes conduct, allowing current to flow in one direction.During the negative half-cycle, the other two diodes conduct, maintaining the same direction of current flow through the load.Thus, a bridge rectifier requires 4 diodes to function properly.
Why the other options are wrong
- B. This is an incorrect optionIt is a fact that a bridge rectifier has 4 diodes. It is also called a full wave rectifier.
- C. This is an incorrect optionIt is a fact that a bridge rectifier has 4 diodes. It is also called a full wave rectifier.
- D. This is an incorrect option.It is a fact that a bridge rectifier has 4 diodes. It is also called a full wave rectifier.
Q156. What is the instantaneous power dissipated through a resistor of resistance 10 ohm if it is connected to an AC source of frequency 15 Hz at 1/180 sec if peak value is 20 V?
- A. 10 W✓
- B. 100 W
- C. 40 W
- D. Cannot be determined
Explanation: UsingVo = V sin(2𝜋ft) = 20 x sin (2𝜋 x 15 x 1/180) = 10 VUsingP = v2/ R = 102 / 10 = 10 W
Why the other options are wrong
- B. Using, Vo= V sin(2πft) = 20 x sin (2π x 15 x 1/180) =10 VUsing,P = v²/R = 102/ 10 = 10 W.
- C. Using, Vo= V sin(2πft) = 20 x sin (2π x 15 x 1/180) =10 VUsing,P = v²/R = 102/ 10 = 10 W.
- D. Using, Vo= V sin(2πft) = 20 x sin (2π x 15 x 1/180) =10 VUsing,P = v²/R = 102/ 10 = 10 W.
Q157. Which one of the following is not electromagnetic in nature?
- A. X-rays
- B. Gamma rays
- C. Cathode rays✓
- D. Infrared rays
Explanation: Cathode rays EM waves travel with a constant velocity of 3.00x10⁸ ms-1 in vacuum. They are deflected neither by the electric field, nor by the magnetic field. These waves do not require a medium to travel from one place to another. As cathode rays negate all these properties, they are not considered as EM waves.
Why the other options are wrong
- A. X-rays follow the properties of EMW. Hence, this option is incorrect.
- B. Gamma rays follow all the properties of EMW. Hence, this option is incorrect.
- D. Infrared rays follow all the properties of EMW. Hence, this option is incorrect.
Q158. Which of the following has zero average value in a plane electromagnetic wave:
- A. Kinetic energy
- B. Magnetic field
- C. Electric field
- D. Both (b) and (c)✓
Explanation: In an electromagnetic wave, the average value of the electric field or magnetic field is zero, because electromagnetic waves are sinusoids and the average of a sinusoid over 1 period is zero.
Why the other options are wrong
- A. Kinetic energy is the energy possessed by an object due to its motion. It depends on both the mass of the object and its velocity. Any object in motion, whether it's a car, a planet, or a particle, has kinetic energy.
- B. A magnetic field is a region of space where a magnetic force can be experienced by a moving electric charge or magnetic material. It is produced by magnetic sources such as magnets, electric currents, and changing electric fields.
- C. An electric field is a region of space around a charged particle or object where other charged particles experience a force. It represents the influence that a charge exerts on the space around it. The strength and direction of the electric field at any point is determined by the amount of charge and the distance from the charge.
Q159. A current carrying solenoid is cut into a ratio 1:3 such that both are independently connected with the same source of current. Now if the magnetic field of the first part is “BA” while the second part respectively is “BB” then what is true?
- A. BA=3BB
- B. BA=(BB)/3
- C. BA=BB✓
- D. BA=4BB
Explanation: Magnetic field in solenoid is independent of length and cross section area;B= 𝛍 nIn=I/Ln= number of turnsI=currentL=lengthB magnetic flux density 𝛍= magnetic Constant Even if solenoid is cut in any ratio; n would still remain the same because magnetic field in solenoid is independent of length and cross section area .If n remains same so will be the magnetic field
Why the other options are wrong
- A. As per the explanation, this is not correct.
- B. As per the explanation, this is not correct.
- D. As per the explanation, this is not correct.
Q160. The region that lies between IR and UV regions is called:
- A. Radio waves
- B. None of these
- C. X ray region
- D. Visible light✓
- E. All of these
Explanation: The visible light region falls between the ultraviolet (UV) and infrared (IR) regions on the electromagnetic spectrum. The UV region has a wavelength in the range of 100-400 nm whereas the IR region has a wavelength in the range of 760-1 million nm. The narrow range of 400-700 nm represents rays in the visible light range; rays of wavelengths visible to the human eye.
Why the other options are wrong
- A. Radio waves have wavelengths longer than infrared light and are typically associated with communication technologies such as radio broadcasting, telecommunications, and radar. They lie at the lower end of the electromagnetic spectrum, well below the infrared region.
- B. This option implies that the region between IR and UV has no specific designation, which is not correct. This region indeed has a specific name, as it encompasses a range of wavelengths with distinct properties.
- C. X-rays have much shorter wavelengths and higher frequencies than ultraviolet (UV) light. They are typically used in medical imaging and security scanning due to their ability to penetrate various materials. X-rays lie well beyond the ultraviolet region on the electromagnetic spectrum.
- E. This option suggests that all the mentioned regions (radio waves, X-ray region, and visible light) lie between IR and UV, which is incorrect. Radio waves are below IR, and X-rays are beyond UV. Visible light is the only region that fits between IR and UV.
Q161. Magnetic force on a charged particle is:
- A. QvBl
- B. None of these
- C. QvB cosθ
- D. QvB sinθ✓
Explanation: When a charge moves through a magnetic field, a force is applied on it which is given by:F = QvB sinθQvBl is the motional EMF produced when a conductor moves through a static magnetic field.
Why the other options are wrong
- A. This formula seems to be a combination of the basic components of the magnetic force equation, but it's not the complete formula. The correct formula includes the sine of the angle between the velocity vector and the magnetic field vector, represented as sin(θ). Therefore, while QvBl captures some aspects of the magnetic force equation, but it's not fully accurate without considering the angle θ.
- B. This option implies that none of the provided options are correct. However, one of the options does represent the correct formula for the magnetic force on a charged particle. As explained earlier, the correct formula is QvBsin(θ), where Q is the charge of the particle, v is the velocity of the particle, B is the magnetic field strength, and θ is the angle between the velocity vector and the magnetic field vector.
- C. his formula represents the component of the magnetic force parallel to the magnetic field, given by cos(θ). However, the correct formula for the magnetic force on a charged particle includes the perpendicular component of the force, represented by sin(θ). Therefore, while QvBcos(θ) is a valid component of the magnetic force, it does not represent the complete formula.
Q162. An electron is moving along the axis of a solenoid carrying a current. Which of the following is a correct statement about the magnetic force acting on the electron?
- A. The force acts radially inwards
- B. The force acts radially downwards
- C. The force acts in the direction of motion
- D. No force acts✓
Explanation: Consider the diagram of magnetic field shown and observe the magnetic field lines.Option D) When an electron moves along the axis of magnetic field in the solenoid the force acting on it will be given by F= qvB. As the electron is moving along the axis, θ will be zero and is zero.Hence no force will act on the electron.Option A, B & C all talk about forces and hence are wrong.
Why the other options are wrong
- A. This option suggests that the force acts towards the center of the solenoid, which is not necessarily true. The force may not be radial, and its direction depends on the specific orientation of the velocity and the magnetic field. Therefore, this option is not necessarily correct.
- B. This option suggests that the force acts in a direction perpendicular to the motion of the electron, which is not necessarily true. The direction of the force depends on the relative orientation of the velocity vector and the magnetic field vector. Therefore, this option is not necessarily correct.
- C. This option suggests that the force acts parallel to the motion of the electron, which is not true according to the right-hand rule. The force due to the magnetic field acts perpendicular to the direction of motion. Therefore, this option is incorrect.
Q163. The motional E.M.F depends upon:
- A. Strength of magnetic field
- B. Speed of the conductor
- C. Length of conductor
- D. All answers are correct✓
Explanation: The factors on which motional emf depends are the magnetic field and velocity and length of the rod. Thus option D is the correct answer.
Why the other options are wrong
- A. By formula as B increases induced motional EMF also increases.
- B. As speed of conductor increases ε also increases.
- C. As L increases ε also increases.
Q164. The cyclotron frequency of an electron projected with velocity perpendicular to a magnetic field B is given by:
- A. f= mB/πC
- B. f= 2πeB/m
- C. f= eB/2πm✓
- D. f= 2πc/mB
Explanation: For a cyclotron Centripetal force is provided by magnetic force.By derivation, A, B & C are wrong.
Why the other options are wrong
- A. The cyclotron frequency is given by f= eB/2πm. Hence this option is incorrect.
- B. The cyclotron frequency is given by f= eB/2πm. Hence this option is incorrect.
- D. The cyclotron frequency is given by f= eB/2πm. Hence this option is incorrect.
Q165. An electron is projected horizontally from south to north in a uniform horizontal magnetic field acting from west to east. The direction along which it will be deflected is:
- A. Northwards
- B. Southwards
- C. Vertically upwards✓
- D. Vertically downwards
Explanation: Apply the rule as shown in the following image.By this, we get a downward direction. But keep in mind we use the right-hand rule for positive charge. In case of a negative charge, we will take opposite conclusions so the direction of force (deflection) would be vertically upward in the case of an electron.
Why the other options are wrong
- A. Using the right-hand rule, the force would be perpendicular to both the velocity of the electron and the magnetic field. This option is incorrect.
- B. Applying the right-hand rule indicates the direction of force is not southwards. Hence, this option is incorrect.
- D. For a positive charge, the force would be directed downwards using the right-hand rule, but for a negative charge like an electron, it is reversed to upwards. This option is incorrect.
Q166. An electron is moving along the axis of a solenoid carrying a current. Which of the following is a correct statement about the electromagnetic force acting on the electron?
- A. The force acts radially inwards
- B. The force acts radially outwards
- C. The force acts in the direction of motion
- D. No force acts✓
Explanation: The question states along the axis of a solenoid. This implies that the Magnetic feild is parallel to the direction of current (For magnetic force to act, it is necessary that the direction of current and magentic feild are perpendicular to eachother) Therefore, no force acts and electron moves straight through without getting deflected.
Why the other options are wrong
- A. No Force will act on an electron, if there was some force then we have to decide its direction.
- B. No Force will act on an electron, if there is some force then we have to decide its direction, As the electron is moving parallel 0° angle or antiparallel 180° with the magnetic field, in both cases, the value of sin is 0 making force 0.
- C. Force always acts perpendicular to the direction of motion, if it acts according to Fleming left-hand rule.
Q167. The magnetic lines of force are directed in a manner that they:
- A. Originate at south pole and terminate at north pole
- B. Pass through the magnet
- C. Originate at north pole and terminate at south pole✓
- D. Go away from both the poles
Explanation: The correct answer is Option C: The magnetic lines of force originate at the north pole and terminate at the south pole. This is because magnetic field lines emerge from the north pole and enter the south pole, completing a loop.Option A is incorrect because it reverses the direction of the magnetic lines of force, which do not originate at the south pole.Option B is incorrect in context because, while magnetic lines do pass through the magnet as continuous loops, it does not address their directional origin and termination.Option D is incorrect because magnetic lines of force do not move away from both poles; they form loops, ensuring the magnetic field is present outside the magnet.
Why the other options are wrong
- A. This is incorrect. The magnetic lines of force originate at the north pole and terminate at the south pole.
- B. This is correct. The magnetic lines of force are continuous, so they must pass through the magnet. They do not pass through the magnet in a straight line, but rather they form loops that go around the magnet.
- D. This is incorrect. The magnetic lines of force do not go away from both the poles. If they did, then the magnetic field would be zero everywhere outside the magnet. However, the magnetic field is not zero outside the magnet. It is strongest near the poles of the magnet, and it decreases as you move away from the poles.
Q168. Which of the following physical phenomena connot be described only by the wave theory of the electromagnetic radiation?
- A. Diffraction
- B. Interference
- C. Photoelectric Effect✓
- D. Polarization
Explanation: The correct answer is the Photoelectric Effect. This phenomenon cannot be adequately described by the wave theory of light alone because it demonstrates that light can behave as a stream of particles (photons), with each photon having a discrete energy that can be transferred to electrons. This is in contrast to wave-based phenomena like diffraction, interference, and polarization, which can be fully explained by the wave theory of electromagnetic radiation.
Why the other options are wrong
- A. Diffraction involves the bending and spreading of waves when they encounter an obstacle or opening. This phenomenon is well-explained by the wave theory of electromagnetic radiation, as it results in patterns of constructive and destructive interference that align with the wave nature of light.
- B. Interference is a result of the superposition of waves from coherent sources. This phenomenon, demonstrated in Young's Double-Slit Experiment, is a classic example of the wave nature of light, where overlapping waves produce regions of reinforcement and cancellation.
- D. Polarization is the process by which the oscillations of light waves are restricted to a single plane. This phenomenon indicates the transverse nature of light waves and is consistent with the wave theory of electromagnetic radiation, as it does not require a particle-like description.
Q169. Which of the following is the same unit as the farad?
- A. Ωs
- B. Ωs–1
- C. Ω–1s✓
- D. Ω–1 s–1
Explanation: Farad is defined as charges held per unit of volt across the capacitor. Charges are current x time. So farad is the current x time over volt, or time over ohm.
Why the other options are wrong
- A. This option is incorrect. The unit 'ohm second' (Ωs) represents resistance multiplied by time, which does not equate to capacitance. In electrical terms, this would instead relate to energy dissipation or other time-dependent resistance phenomena, not capacitance.
- B. This option is incorrect. The unit 'ohm per second' (Ωs–1) represents resistance divided by time, which is not equivalent to capacitance. This unit does not align with the dimensional analysis required for capacitance.
- D. This option is incorrect. The unit 'per ohm per second' (Ω–1 s–1) represents conductance per time, not capacitance. This unit is associated with a rate of change of conductance rather than the ability to store charge.
Q170. In a ripple tank, 40 waves pass through a certain point in 1 second. If the wavelength of the wave is 5 cm, then speed of the wave is:
- A. 0.5 ms-1
- B. 1 ms-1
- C. 1.5 ms-1
- D. 2 ms-1✓
Explanation: Use the formula “v=fλ”As it is known that 40 waves pass through the point in 1 second so frequency is 40.Wavelength is 5cm which can be converted to 0.05m as all options are having units in ms-1(metres per second).v=(0.05)(40)v=2ms-1
Why the other options are wrong
- A. This is not correct according to the calculations.Use the formula “v=fλ”As it is known that 40 waves pass through the point in 1 second so frequency is 40.Wavelength is 5cm which can be converted to 0.05m as all options are having units in ms-1(metres per second).v=(0.05)(40)v=2ms-1
- B. This is not correct according to the calculations.Use the formula “v=fλ”As it is known that 40 waves pass through the point in 1 second so frequency is 40.Wavelength is 5cm which can be converted to 0.05m as all options are having units in ms-1(metres per second).v=(0.05)(40)v=2ms-1
- C. This is not correct according to the calculations.Use the formula “v=fλ”As it is known that 40 waves pass through the point in 1 second so frequency is 40.Wavelength is 5cm which can be converted to 0.05m as all options are having units in ms-1(metres per second).v=(0.05)(40)v=2ms-1 .
Q171. If the potential at a point which is 1m from a charge is 1 volt, then the potential at a point which is 2m from the same charge will be:
- A. 2 V
- B. 1 V
- C. 0.5 V✓
- D. 3 V
Explanation: The electric potential V at a distance r from a charge is given by the formula V = kQ/r, where k is Coulomb's constant and Q is the charge. When the distance from the charge is doubled, the potential is halved because V is inversely proportional to the distance. Thus, if the potential is 1 V at 1 m, it will be 0.5 V at 2 m. Option C is correct because it reflects this relationship. Options A and D are incorrect because they suggest the potential increases with distance, which is not the case. Option B is incorrect because it implies the potential remains the same regardless of distance, which contradicts the inverse relationship between potential and distance.
Why the other options are wrong
- A. This is incorrect. Doubling the distance from the charge does not double the potential; it reduces it.
- B. This is incorrect. The potential at a different distance from the charge changes according to the inverse relationship with distance.
- D. This is incorrect. The potential does not increase with distance; it decreases.
Q172. Find the missing number in the series: 6, 3, 3, 4.5, ?
- A. 5.5
- B. 7
- C. 9✓
- D. 11.5
Explanation: The sequence follows a pattern where each number is multiplied by an incrementally increasing factor. The operations are: 6 × 0.5 = 3; 3 × 1 = 3; 3 × 1.5 = 4.5. The next step is 4.5 × 2 = 9.
Why the other options are wrong
- A. This option does not follow the increasing multiplication pattern observed in the sequence.
- B. This option does not fit the established pattern of multiplying by incremental factors.
- D. This number does not fit the pattern of multiplication with increasing factors applied to the sequence.
Q173. Find the missing number in the series: 4, 6, 10, 14, 22, 26, 34, 38, 46, ?
- A. 62
- B. 58✓
- C. 26
- D. 42
Explanation: This series is generated by multiplying 2 by the sequence of prime numbers. The terms are 2×2, 2×3, 2×5, 2×7, 2×11, and so on. The next prime after 23 is 29, so the missing term is 2 × 29 = 58.
Why the other options are wrong
- A. This is incorrect. The series involves multiplying 2 with consecutive prime numbers, and 62 is not a result of this pattern.
- C. This is incorrect. The number 26 is already in the series as a result of 2*13. The series continues with larger prime numbers.
- D. This is incorrect. While 42 is a product of multiplication, it does not fit the specific pattern of multiplying 2 by consecutive prime numbers.
Q174. Find the missing number in the series: 1, 5, 13, 25, ?
- A. 41✓
- B. 44
- C. 23
- D. 21
Explanation: The difference between consecutive terms increases by 4 each time. The differences are +4, +8, +12. The next difference will be +16. Therefore, the missing term is 25 + 16 = 41.
Why the other options are wrong
- B. Incorrect. This assumes a difference of 19 after 25, which breaks the established pattern of increasing differences by 4.
- C. Incorrect. This choice does not follow the pattern of increasing differences. The difference after 25 should be 16, not a decrease.
- D. Incorrect. Choosing this option disregards the increasing nature of the differences, as the number should be greater than 25.
Q175. Statement: There is an unprecedented increase in the migration of villagers to urban areas as repeated crop failure has put them into a precarious financial situation.Courses of Action:I. The villagers should be provided with an alternate source of income in their villages which will make them stay put.II. The migrated villagers should be provided with jobs in the urban areas to help them survive.
- A. Only I follows✓
- B. Only II follows
- C. Either I or II follows
- D. Both I and II follow
Explanation: Action I addresses the root cause of the problem (lack of income in villages) and is a sustainable, long-term solution. Action II is a temporary fix that could encourage more migration and further strain urban resources. Therefore, Action I is the more logical course.
Why the other options are wrong
- B. Wrong because providing jobs in cities accepts migration instead of solving the cause, and does not reduce rural distress.
- C. Wrong because Course II is not an appropriate corrective action; only Course I is logical
- D. Wrong because Course II does not solve the problem stated; hence both do not follow.
Q176. Statements:All flowers are trees. No fruit is tree.Conclusions:I. No fruit is flower.II. Some trees are flowers.Which of the following is/are most appropriate in the above scenario?
- A. Only I
- B. Only II
- C. I and II✓
- D. I and II are inappropriate
Explanation: Statements:All flowers are trees.No fruit is tree.Conclusions:I. No fruit is flower. This follows.Since all flowers are trees and no fruit is a tree, then by logic, no fruit can be a flower either.II. Some trees are flowers. This also follows.Statement 1 clearly says all flowers are trees, so definitely some trees are flowers.Answer:Both Conclusion I and II follow.
Why the other options are wrong
- A. This is incorrect as II also follows.
- B. This is incorrect as I also follows.
- D. This is incorrect as I and II both follows.
Q177. In the following question, various terms of an alphabet sequence are given with one or more terms missing as shown by (?). Choose the missing term.Z, ?, T, ?, N, ?, H, ?, B
- A. W, Q, K, E✓
- B. W, R, K, E
- C. X, Q, K, E
- D. X, R, K, E
Explanation: Step 1: Identify the PatternLooking at the given letters:Z → ? → T → ? → N → ? → H → ? → BObserving the position of these letters in the English alphabet:Z (26)T (20)N (14)H (8)B (2)We see that the letters are decreasing in steps of 6:Z (26) → T (20) → N (14) → H (8) → B (2)Each step decreases by 6.Step 2: Fill in the Missing TermsNow, following the pattern:Z (26) → (26 - 6) = T (20)T (20) → (20 - 6) = N (14)N (14) → (14 - 6) = H (8)H (8) → (8 - 6) = B (2)Thus, the missing terms are:Between Z and T: (26 - 3) = W (23)Between T and N: (20 - 3) = Q (17)Between N and H: (14 - 3) = K (11)Between H and B: (8 - 3) = E (5)Final Sequence:Z, W, T, Q, N, K, H, E, BAnswer: W, Q, K, E
Why the other options are wrong
- B. This is incorrect.Answer: W, Q, K, E
- C. This is incorrect.Answer: W, Q, K, E
- D. This is incorrect.Answer: W, Q, K, E
Q178. Directions: Read the following information and give answer.Ghulam Rasool is shorter than Ali but taller than Kamran.Naeem is shorter than Kamran.Jameel is taller than Naeem.Ali is taller than Jameel.Who among them is the tallest?
- A. Ali✓
- B. Naeem
- C. Kamran
- D. Jameel
Explanation: Let's analyze the statements:Ghulam Rasool is shorter than Ali but taller than Kamran.Naeem is shorter than Kamran.Jameel is taller than Naeem.Ali is taller than Jameel.From these statements, we can deduce the order:Ali > Ghulam Rasool > Kamran > NaeemAli > Jameel > NaeemThus, Ali is taller than everyone else, making him the tallest.Other options are incorrect because they do not satisfy all the conditions provided in the statements.
Why the other options are wrong
- B. Naeem is shorter than Kamran and Jameel, which automatically disqualifies him from being the tallest.
- C. Kamran is shorter than Ghulam Rasool and taller than Naeem; therefore, he is not the tallest.
- D. Jameel is shorter than Ali, which means he cannot be the tallest.
Q179. STATEMENTS:I. The dialogue between Jinnah and Gandhi failed.Il. Indian National Congress and Muslim League tried to join hands, so they will be united.
- 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 statements I and II are independent causes
- D. Both statements I and II are the effects of independent cause.✓
Explanation: Gandhi and Jinnah were unable to reach a decision regarding Pakistan hence the dialogue failed. In order to show a united front to the British as they believe that would help them achieve independence INC and ML tried to join hands(work together). Thus both these statements are effects of independent causes.
Why the other options are wrong
- A. Gandhi and Jinnah were unable to reach a decision regarding Pakistan hence the dialogue failed. In order to show a united front to the British as they believe that would help them achieve independence INC and ML tried to join hands(work together). Thus both these statements are effects of independent causes.
- B. Gandhi and Jinnah were unable to reach a decision regarding Pakistan hence the dialogue failed. In order to show a united front to the British as they believe that would help them achieve independence INC and ML tried to join hands(work together). Thus both these statements are effects of independent causes.
- C. Gandhi and Jinnah were unable to reach a decision regarding Pakistan hence the dialogue failed. In order to show a united front to the British as they believe that would help them achieve independence INC and ML tried to join hands(work together). Thus both these statements are effects of independent causes.
Q180. Statements: The increasing population of our nation will lead to the depletion of many essential resources.Conclusions:I. Population of our nation can be controlled.II. The nation will not be able to provide a decent living to its citizens.
- A. Only conclusion I follows
- B. Only conclusion II follows✓
- C. Either conclusion I or II follows
- D. Both conclusions I and II follow
Explanation: The statement directly links population growth to the depletion of essential resources. A lack of essential resources logically implies that providing a decent living for all citizens will become difficult or impossible, making Conclusion II a direct inference. The statement does not provide information about whether the population can be controlled.
Why the other options are wrong
- A. This is incorrect. The statement does not provide any information or inference about controlling the population; it only discusses the consequences of an increasing population.
- C. This is incorrect. Conclusion II follows directly from the statement, while conclusion I does not. Therefore, both cannot be considered equally valid conclusions.
- D. This is incorrect. While conclusion II is supported by the statement, conclusion I is not addressed at all by the given information, making this option invalid.
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