Etea Mdcat 2012 — Solved Past Paper with Answers

Q1. When you go to Karachi,please

• A. Collect a good watch for me.
• B. Acquire a good watch for me.
• C. Bring a good watch for me.✓
• D. Arrange a good watch for me.

Explanation: The correct answer is Option C: 'Bring a good watch for me.' The term 'bring' is appropriate because it involves taking an item with you from one location to another, specifically towards the speaker, which fits the context of the sentence. Option A 'Collect' suggests gathering multiple items rather than focusing on a single watch. Option B 'Acquire' implies obtaining or purchasing, not necessarily bringing back. Option D 'Arrange' involves planning or organizing, which does not align with the action of physically transporting an item.

Q2. Why have you broken this jug? The passive form of the sentence is:

• A. Why has this jug been broken by you?✓
• B. Why have this jug been broken by you?
• C. Why this jug has been broken by you?
• D. Why had that jug been broken by you?

Explanation: The correct passive form of the sentence is 'Why has this jug been broken by you?'. The original sentence is in present perfect tense, which requires 'has/have + been + past participle' structure in passive voice. 'Has' is used for singular nouns like 'jug'. Option A correctly follows this structure. Option B incorrectly uses 'have' instead of 'has'. Option C improperly structures the question by placing the auxiliary verb after the subject. Option D shifts to past perfect tense, which is not applicable here.

Q3. Remember to brush your teeth after dinner, "she said. The indirect form of the sentence is:

• A. She told him to remember to brush his teeth after dinner.
• B. She reminded him to brush his teeth after dinner.✓
• C. She advised him to remember to brush his teeth after dinner.
• D. She said to him to remember to brush his teeth after dinner.

Explanation: Indirect Speech = Reported SpeechIndirect speech differs from direct speech in that we DO NOT tell exactly what another person said. We are NOT repeating what someone else said. John says: I’m a good boy.We say: John said he was a good boy.

Q4. You did not kill a lion in the forest. Passive form of the sentence as:

• A. A lion is not killed by you in the forest.
• B. A lion was not killed by you in the forest.✓
• C. A lion is killed not by you in the forest.
• D. A lion has not killed by you in the forest

Explanation: The correct passive form of the sentence 'You did not kill a lion in the forest.' is 'A lion was not killed by you in the forest.' This transformation requires changing the active voice past indefinite tense ('did not kill') to its passive form, which involves using 'was' for past tense along with the past participle of the verb ('killed'). The subject and object are inverted in passive voice, with 'a lion' becoming the subject. Other options are incorrect due to tense misalignment or incorrect verb form use.In passive voice:Object +was/were+not+3rd form of verb+by+subject.

Q5. Mathematics_ difficult but fascinating.

• A. seems✓
• B. is seeming
• C. seemed
• D. seem

Explanation: The correct answer is 'seems' because 'Mathematics' is treated as a singular noun in English, even though it ends with an 's'. Therefore, it requires a singular verb form. 'Is seeming' is incorrect as 'seem' is rarely used in the continuous tense. 'Seemed' is incorrect because it is past tense, while the sentence is in present tense. 'Seem' is incorrect because it is a plural verb form.Some nouns are deceptive; they are singular.i.e: Physics,News,Sports,Politics etc.With singular nouns, we use singular verbs. Singular verbs:goes,plays,writesPlural verbs:go,play,write.

Q6. Please come to the point; don‘t beat _ the bush.

• A. across
• B. about✓
• C. along
• D. round

Explanation: Please come to the point,don’t beat about the bush.

Q7. She has complained _ me to the principal.

• A. about
• B. from
• C. against✓
• D. over

Explanation: The correct answer is 'against' because it implies that the complaint was directed in opposition to 'me' to the principal. The other options do not fit the context: 'about' would imply discussing a topic, 'from' would suggest origin, and 'over' does not relate to the context of a complaint.

Q8. I said to him, "Can you read this letter?"‘ Indirect form of the sentence is:

• A. I said to him whether he read that letter.
• B. I asked him if could he read this letter.
• C. I told him that he could read that letter.
• D. I asked him if he could read that letter.✓

Explanation: The correct answer is: I asked him if he could read that letter.When converting direct speech to indirect speech, questions are often introduced with 'asked' and the word order is changed from that of a direct question. The pronoun 'you' changes to 'he', and 'this' changes to 'that'. The auxiliary verb 'can' changes to 'could' to reflect the backshift in tense.Option A is incorrect because it uses 'read' in the past tense without the auxiliary 'could'.Option B is incorrect because it retains the question word order of direct speech, which is not used in indirect speech.Option C is incorrect because it alters the sentence from a question to a statement, thus changing its meaning.If the Reported Speech in Direct Narration is introduced by Verbs like “ be”, “have”, “do”, or any other auxiliary Verbs like “can”, “shall”, “will”, the connective “ if ”, “ whether ” is used after the Reporting Verb or object of the Reporting verb in the Indirect Narration.

Q9. If you want to play cricket,

• A. you ought to join our club.✓
• B. you ought to join with our club.
• C. you ought joined our club.
• D. you ought to join in our club.

Explanation: The correct sentence is 'you ought to join our club.' The construction of 'ought to' requires a base verb form, making 'join' the correct choice. In Options B and D, the words 'with' and 'in' are unnecessary because they do not fit grammatically in this context. Option C is incorrect because it omits 'to' and uses 'joined' instead of the base form 'join'.

Q10. Allah, the Almighty, has blessed him_ a son.

• A. by
• B. along
• C. from
• D. with✓

Explanation: The correct answer is 'with', as it appropriately conveys the idea of accompanying or possessing, i.e., being blessed with a son. The other options ('by', 'along', 'from') do not fit the context of the sentence as they convey different meanings not relevant to the context of receiving a blessing.

Q11. You need to go to the hospital _ possible. An erratic heartbeat can be very dangerous.

• A. as good as
• B. as long as
• C. as much as
• D. as soon as✓

Explanation: The correct answer is 'as soon as possible' because the sentence emphasizes the need for immediate medical attention due to the danger of an erratic heartbeat. 'As soon as' conveys urgency and promptness. The other options are incorrect as they do not convey the necessary urgency: 'as good as' relates to quality, 'as long as' refers to duration, and 'as much as' concerns quantity.

Q12. Ghani Khan is_ of Pashto.

• A. John Keats
• B. a John Keats
• C. the John Keats✓
• D. like John Keats

Explanation: The correct answer is 'the John Keats'. In literature, when a proper noun is used symbolically to represent a certain quality, role, or influence, the article 'THE' is used. Ghani Khan is being compared to John Keats in terms of his contribution to Pashto literature, hence 'the John Keats'. The other options do not correctly apply the symbolic use of the article or the noun.Generally, we don't use the article 'THE' with a proper noun but if the proper noun is used as a symbol as in our question, we use the article 'THE' with a proper noun.

Q13. Did he buy a car yesterday? The passive form of the sentence is:

• A. Was a car bought by him yesterday?✓
• B. Has a car been bought by him yesterday?
• C. Is a car bought by him the other day?
• D. Had a car been bought by him yesterday?

Explanation: The correct answer is Option A: 'Was a car bought by him yesterday?' The original sentence 'Did he buy a car yesterday?' is in the simple past tense. To convert it to passive voice, the object 'a car' is placed at the beginning, followed by the appropriate form of 'to be' in the past tense ('was' for singular nouns), then the past participle of the verb ('bought'), and finally 'by him' to indicate the doer of the action. Options B, C, and D are incorrect as they use different tenses or alter the sentence structure, which changes the intended meaning of the original sentence.

Q14. Choose the correct sentence out of the following:

• A. Each of them deserves praise
• B. Each one of them deserves praise
• C. Each one of them deserve praise
• D. Every one of them deserves praise.✓

Explanation: The word 'each' refers to individual things within a group of two or more. While each can be used for two or more groups, 'Every' refers to groups of at least three items. Additionally, everyone refers to the collective whole, not just the individuals.

Q15. Choose the correct sentence out of the following;

• A. The meeting does not approve in your scheme.
• B. The meeting do not approves of your scheme.
• C. The meeting does not approve of your scheme.✓
• D. The meeting does not approve about your scheme

Explanation: The correct answer is Option C: 'The meeting does not approve of your scheme.' This sentence correctly uses 'does not' for a third-person singular subject ('the meeting') and the appropriate prepositional phrase 'approve of'. The other options are incorrect because they either use the wrong verb form or the wrong preposition.

Q16. He said to me, May you succeed in life!" The indirect form of the sentence is:

• A. He said to me that may you succeed in life
• B. He prayed that I might succeed in life.✓
• C. He prayed that he might succeed in life
• D. He prayed that you may succeed in life

Explanation: The correct answer is Option B: 'He prayed that I might succeed in life.' In indirect speech, 'may' is often changed to 'might' to reflect the past tense, and 'said' is replaced with 'prayed' to reflect the wishful intention. The pronoun 'you' is also changed to 'I' to match the perspective of the person being addressed. Other options either retain the direct speech format or incorrectly alter the pronoun and tense.

Q17. They arrived at about midnight _.

• A. because their flight was detained.
• B. because their flight was delayed.✓
• C. because their flight was derailed.
• D. because their flight was diverted.

Explanation: The sentence indicates that they arrived at about midnight, suggesting a delay in their flight's arrival time. Therefore, 'delayed' is the most appropriate choice, as it directly relates to the flight arriving later than scheduled. 'Detained' is inappropriate as it refers to holding people, 'derailed' is irrelevant to flights, and 'diverted' implies a change of destination rather than a delay in arrival time.

Q18. If it did not rain in time, there _ a horrible famine.

• A. would have been
• B. will be
• C. would be✓
• D. will have been

Explanation: The correct answer is 'would be' because the sentence describes a hypothetical situation that depends on a specific condition (rain). This is a classic example of a second conditional sentence, which is used for unreal situations in the present or future. The other options are incorrect because they either imply a certainty (as with 'will be'), refer to a past hypothetical (as with 'would have been'), or suggest a completed action before another future event (as with 'will have been').

Q19. Glycolysis completes with the net gain of:

• A. 2 ATP✓
• B. 3 ATP
• C. 4 ATP
• D. 32 ATP

Explanation: Glycolysis is the process of breaking down one molecule of glucose into two molecules of pyruvate. During this process, 4 ATP molecules are produced in total; however, 2 ATP molecules are consumed in the initial steps. Therefore, the net gain of ATP from glycolysis is 2 ATP. Option A is correct.Options B and C are incorrect as they do not account for the consumption of 2 ATP during the process. Option D is incorrect because it refers to the ATP yield from the complete oxidation of glucose during cellular respiration, including the Krebs cycle and oxidative phosphorylation, not just glycolysis.

Q20. Restriction enzymes are of great use in genetic engineering because:

• A. They cut DNA at specific base sequences✓
• B. They cut DNA at multiple random sites
• C. They help in joining the pieces of DNA
• D. They are a type of nuclease

Explanation: Restriction enzymes, also known as restriction endonucleases, are proteins that cut DNA at specific sequences called restriction sites. This ability to make precise cuts at known locations makes them invaluable tools in genetic engineering, allowing for the targeted modification of genetic material. This specificity differentiates them from other enzymes that may cut DNA randomly or serve different functions, such as DNA ligases which are used to join DNA fragments. Options B, C, and D do not accurately describe the precise and sequence-specific cutting function of restriction enzymes, which is critical for their application in genetic engineering.

Q21. Abscisic acid promotes:

• A. Triple response
• B. Sex expression
• C. Flower initiation
• D. Leaf, flower, and fruit fall✓

Explanation: Abscisic acid (ABA) is a plant hormone that plays a key role in inhibiting growth and promoting dormancy in plants. It is particularly known for its role in the abscission or shedding of leaves, flowers, and fruits, especially under stress conditions such as drought. This is why it is sometimes referred to as the 'stress hormone.' The other options relate to functions typically influenced by other hormones: the triple response is associated with ethylene, sex expression is influenced by gibberellins and ethylene, and flower initiation is promoted by gibberellins.

Q22. Surplus amino acids in the body are broken down to form urea in:

• A. Spleen
• B. Kidneys
• C. Liver✓
• D. Pancreas

Explanation: The liver is the primary organ where surplus amino acids are broken down. During this process, the amino group of the amino acids is removed in a process known as deamination, resulting in the formation of ammonia. The liver then converts this toxic ammonia into urea through the ornithine cycle, a less toxic compound that can be safely excreted by the kidneys. Other organs, such as the spleen, kidneys, and pancreas, have different primary functions and are not involved in this specific metabolic pathway.

Q23. Lipids are chemically

• A. Acids
• B. Alcohols
• C. Ethers
• D. Esters✓

Explanation: Lipids are chemically classified as esters because they are formed through a reaction between fatty acids and an alcohol (typically glycerol), resulting in the formation of ester bonds. This gives lipids their characteristic properties, such as hydrophobicity and energy storage capacity. Acids, alcohols, and ethers, while related to lipids in some contexts, do not accurately describe the overall chemical structure of lipids.

Q24. Which of the following represents the bile salts?

• A. Cholic acid✓
• B. Biliverdin
• C. Haemoglobin
• D. Both (A) and (B)

Explanation: Bile salts are synthesized in the liver from cholesterol-derived bile acids such as cholic acid. These acids are conjugated with amino acids like glycine or taurine to form bile salts, which play a crucial role in the digestion and absorption of fats. Cholic acid is a primary bile acid that becomes a bile salt upon conjugation. Biliverdin and bilirubin are pigments associated with bile but do not contribute to the formation of bile salts. Haemoglobin is unrelated to the bile system.

Q25. The conversion of excess glucose into fat is known as:

• A. Glycolysis
• B. Lipogenesis✓
• C. Ketogenesis
• D. Glycogenesis

Explanation: The correct answer is lipogenesis, which refers to the conversion of excess glucose into fat. This process allows the body to store energy when intake exceeds expenditure. Glycolysis, on the other hand, breaks down glucose for immediate energy use, whereas ketogenesis generates energy from fats when glucose is scarce. Glycogenesis stores glucose as glycogen, not fat, making these processes distinct from lipogenesis.

Q26. Fatigue-free muscles are:

• A. Striped
• B. Unstriped
• C. Cardiac✓
• D. Triceps

Explanation: The correct answer is 'Cardiac' because cardiac muscles are uniquely adapted to contract continuously throughout a person's life without tiring. They have a high density of mitochondria, which provides the energy needed for sustained activity. In contrast, striped (skeletal) muscles are voluntary and can fatigue with excessive use, unstriped (smooth) muscles can also fatigue under certain conditions, and the triceps are a specific group of skeletal muscles that can tire with activity.

Q27. Excretion of bile pigments in blood indicates:

• A. Anaemia
• B. Diabetes
• C. Rickets
• D. Jaundice✓

Explanation: The correct answer is Jaundice. Jaundice is characterized by a yellowing of the skin, eyes, and mucous membranes due to elevated levels of bilirubin, a bile pigment, in the blood. This condition often indicates liver dysfunction or bile duct obstruction. Anaemia, Diabetes, and Rickets do not involve bile pigment excretion. Anaemia relates to blood cells, Diabetes to insulin and blood sugar, and Rickets to vitamin D deficiency.

Q28. An individual with contrasting alleles is called

• A. Homozygous
• B. Monoecious
• C. Heterozygous✓
• D. Dioecious

Explanation: An individual with contrasting alleles is called Heterozygous. This means that the organism has two different alleles (such as Tt) for a particular trait, allowing for genetic variation. The term Homozygous refers to having identical alleles (such as TT or tt), which does not involve contrasting alleles. Monoecious and Dioecious are terms related to the reproductive structures of organisms and do not pertain to allelic composition.

Q29. The color of bone marrow is:

• A. Red
• B. Yellow
• C. Orange
• D. Both (A) and (B)✓

Explanation: Bone marrow is the soft tissue inside bones. There are two types: red bone marrow, which is involved in blood cell production, and yellow bone marrow, which primarily stores fat. Both red and yellow marrow exist in the body, depending on the bone and age. Thus, the correct answer is Both (A) and (B). Option C, Orange, is incorrect as orange is not a recognized color of bone marrow.

Q30. Enzymes are basically

• A. Proteins✓
• B. Carbohydrates
• C. Hydrocarbons
• D. None of the above

Explanation: Enzymes are specialized proteins that catalyze biochemical reactions, enabling them to occur more rapidly and efficiently. Their structure allows them to bind to specific substrates and lower the activation energy required for reactions. Carbohydrates, while essential for energy, do not serve this catalytic role, and hydrocarbons are simple organic compounds that lack the complexity and functionality of enzymes.

Q31. A non-connective tissue is:

• A. Areolar tissue
• B. Tendon
• C. Neuron✓
• D. Ligament

Explanation: Neurons are specialized cells that make up nervous tissue, which is responsible for transmitting signals throughout the body. Unlike connective tissues, such as areolar tissue, tendons, and ligaments, which support, bind, or separate other tissues and organs, neurons are involved in communication within the nervous system. Therefore, neurons do not fall under the category of connective tissue, making option C the correct answer.

Q32. Speech and language areas are located in:

• A. Thalamus
• B. Medulla oblongata
• C. Right cerebral hemisphere
• D. Left cerebral hemisphere✓

Explanation: The correct answer is the left cerebral hemisphere. This hemisphere is crucial for language and speech functions, containing key areas such as Broca's and Wernicke's areas. These regions are essential for the production and understanding of speech. In contrast, the thalamus serves as a relay station for sensory information, the medulla oblongata manages autonomic functions, and the right cerebral hemisphere is more involved in spatial and non-verbal tasks, not language processing.

Q33. Phytochromes are involved in:

• A. Phototropism
• B. Photorespiration
• C. Photoperiodism✓
• D. Geotropism

Explanation: Phytochrome senses day length → regulates flowering.

Q34. A botanist who proposed the cell theory was:

• A. Matthias Schleiden✓
• B. Theodor Schwann
• C. Robert Hooke
• D. Robert Brown

Explanation: The cell theory, a fundamental principle in biology, was proposed by Matthias Schleiden and Theodor Schwann. Schleiden, being a botanist, focused on plant cells and their structure, contributing to the theory's formulation. While Schwann also contributed significantly, he was a zoologist. Robert Hooke's work was pivotal in cell observation, but not in theory formulation, and Robert Brown's discovery of the nucleus was a separate contribution to cell biology.

Q35. Smooth endoplasmic reticulum makes:

• A. Enzymes
• B. Protein
• C. Sugar
• D. Lipids✓

Explanation: The smooth endoplasmic reticulum (SER) is primarily responsible for the synthesis of lipids, which include phospholipids, cholesterol, and steroids. These lipids are crucial for the construction of cell membranes and hormone production. The SER does not synthesize proteins or enzymes, as these require ribosomes found on the rough endoplasmic reticulum (RER). Additionally, sugar synthesis, such as gluconeogenesis, occurs elsewhere in the cell, not in the SER.

Q36. How many atoms of oxygen in R.N.A. are greater than D.N.A.?

• A. One✓
• B. Two
• C. Three
• D. Four

Explanation: RNA (Ribonucleic Acid) and DNA (Deoxyribonucleic Acid) differ in their sugar components. RNA contains ribose sugar, which has a hydroxyl group (-OH) at the 2' carbon, whereas DNA contains deoxyribose sugar, which lacks this oxygen-containing group at the same position, having just a hydrogen atom instead. This results in RNA having one more oxygen atom than DNA. This single oxygen atom difference is crucial for the biological functions and structural properties of RNA compared to DNA. Therefore, the answer is 'One'.

Q37. Growth promoting substance in plant is:

• A. F.A.D
• B. Chlorophyll a
• C. I.A.A✓
• D. ABA

Explanation: The correct answer is I.A.A (Indole-3-acetic acid), which is an auxin, a class of plant hormones that are essential for cell elongation, root development, and various other growth processes. Auxins like I.A.A are key in regulating plant growth and encouraging developmental changes.F.A.D is unrelated to growth promotion because it functions primarily in energy transfer and redox reactions. Chlorophyll a is essential for photosynthesis, converting light energy into chemical energy, but it is not a hormone involved in growth promotion. ABA, while important for stress response and dormancy, acts more as a growth inhibitor rather than a promoter.

Q38. Steroid hormones are produced by:

• A. Testes and ovaries
• B. Adrenal glands and gonads
• C. Adrenal cortex and gonads✓
• D. Gonads and thyroids

Explanation: Steroid hormones are primarily produced by the adrenal cortex and the gonads. The adrenal cortex synthesizes glucocorticoids, mineralocorticoids, and androgens, while the gonads produce sex hormones like androgens, estrogens, and progesterone. The adrenal medulla, mentioned in Option B, produces catecholamines, not steroid hormones. The thyroid gland, mentioned in Option D, produces thyroid hormones, which are not steroids.

Q39. B.C.G vaccines are usually given to:

• A. Children✓
• B. Adults
• C. Special populations
• D. All of the above

Explanation: The Bacillus Calmette-Guerin (BCG) vaccine is primarily given to children, especially in countries where tuberculosis (TB) is prevalent, because it is most effective at preventing severe forms of TB in young children. It is not typically given to adults because its effectiveness in preventing TB in adults is limited. Similarly, while some special populations might receive the vaccine, it is not routinely administered to all of them.

Q40. Proteins, carbohydrates, and fats form three great classes of foodstuffs commonly called:

• A. Trivirates
• B. Triumvirates✓
• C. Trisvirates
• D. All of the above

Explanation: The correct answer is 'Triumvirates.' This term is used to describe a powerful group of three, which in this context applies to the three macronutrient classes: proteins, carbohydrates, and fats. These groups work together to provide energy and maintain bodily functions. The other options, 'Trivirates' and 'Trisvirates,' do not exist as terms and have no relevance in the classification of foodstuffs.

Q41. Replication of D.N.A occurs in:

• A. Interphase✓
• B. Prophase
• C. Metaphase
• D. Anaphase

Explanation: The correct answer is Interphase. During interphase, the cell prepares for division, and the DNA in the nucleus replicates. This phase includes the G1 phase (cell growth), the S phase (DNA synthesis), and the G2 phase (preparation for mitosis). The other options, Prophase, Metaphase, and Anaphase, are all stages of mitosis where DNA replication does not occur; instead, they involve the organization and separation of already duplicated chromosomes.

Q42. Regeneration of cartilage is carried on by:

• A. Collagenous fibers
• B. Blood vessels
• C. Perichondrium
• D. Matrix✓

Explanation: The correct answer is the 'Matrix.' The matrix is essential for the regeneration of cartilage as it provides a scaffold for cellular attachment, growth, and communication. While collagenous fibers and the perichondrium contribute to the structure and minor repair, they are not the main agents of regeneration. Blood vessels, being absent in cartilage, play no role in its regeneration.

Q43. Nuclear mitosis occurs in the kingdom of:

• A. Monera
• B. Protista
• C. Plantae
• D. Fungi✓

Explanation: Nuclear mitosis is characterized by the retention of the nuclear membrane throughout the process. This type of mitosis occurs only in the kingdom Fungi, where the mitotic spindle forms inside the nucleus. In contrast, in the kingdoms Monera, Protista, and Plantae, the nuclear membrane disassembles during mitosis, which is typical for standard mitotic processes in eukaryotic cells.

Q44. The sense of hearing is concerned with:

• A. Cerebrum✓
• B. Cerebellum
• C. Medulla
• D. Hypothalamus

Explanation: The cerebrum is the largest part of the brain and is responsible for processing and interpreting sensory information, including sound, which is why it is associated with the sense of hearing. The other options, such as the cerebellum, medulla, and hypothalamus, have different functions related to movement coordination, autonomic regulation, and homeostasis, respectively, and do not directly handle auditory processing.

Q45. The largest lymphatic duct is the:

• A. Abdominal duct
• B. Thoracic duct✓
• C. Femoral duct
• D. Subclavian duct

Explanation: The thoracic duct is the largest lymphatic duct in the body. It collects lymph from most of the body (except the right arm and right side of the head and thorax) and drains it into the bloodstream via the left subclavian vein. This duct is crucial for maintaining fluid balance and immune function. The other options are either inaccurately named or incorrectly identified as lymphatic ducts. The abdominal and subclavian ducts do not exist as discrete entities in the lymphatic system, and the femoral duct is not a recognized component of this system.

Q46. In human being, the number of cranial nerves are:

• A. 8 pairs
• B. 10 pairs
• C. 12 pairs✓
• D. 31 pairs

Explanation: Humans have 12 pairs of cranial nerves that emerge directly from the brain, each designated with a specific function. These nerves are classified as sensory, motor, or mixed, based on their primary functions. Option C is correct as it accurately reflects the number of cranial nerve pairs. Option A (8 pairs) and Option B (10 pairs) are incorrect as they underestimate the actual number. Option D (31 pairs) is incorrect because it refers to the number of spinal nerve pairs, not cranial nerves.

Q47. Live attenuated vaccines are used to treat all of the following diseases except:

• A. Typhoid and plague
• B. Polio and measles
• C. Cholera and rabies✓
• D. Mumps and influenza

Explanation: Live attenuated vaccines are designed to provoke a strong immune response by using a weakened form of the virus. They are used for diseases like measles, mumps, and polio. However, cholera and rabies vaccines do not typically use live attenuated strains. Cholera vaccines are usually inactivated, while rabies vaccines are inactivated or recombinant. Understanding the specific vaccines available for each disease is crucial for answering this question correctly.

Q48. All of the following are polysaccharides except:

• A. Glycogen
• B. Cellulose
• C. Starch
• D. Glucose✓

Explanation: Glucose is the correct answer because it is a monosaccharide, meaning it is a single sugar unit and not a polysaccharide. Polysaccharides are complex carbohydrates composed of many sugar units linked together. Cellulose and starch are both polysaccharides, with cellulose consisting of beta glucose units and starch comprising alpha glucose units. Therefore, glucose is the only option that is not a polysaccharide.

Q49. A single ovum of a human being contains:

• A. X — chromosome✓
• B. XX — chromosomes
• C. YY — chromosomes
• D. XY — chromosomes

Explanation: The correct answer is that a single ovum of a human being contains an X chromosome. This is because the ovum is a haploid cell, meaning it contains only one set of chromosomes, specifically an X chromosome. Human females have two X chromosomes (XX), and during the formation of gametes, one of these X chromosomes is passed on to the ovum. Other options are incorrect because:XX — chromosomes: This configuration is found in diploid cells, not haploid cells like the ovum.YY — chromosomes: Such a combination is not naturally occurring in human biology.XY — chromosomes: This is the typical male chromosome configuration, which is not found in the ovum.

Q50. In a dihybrid cross, how many homozygous offsprings can be produced?

• A. 4✓
• B. 3
• C. 2
• D. 9

Explanation: In a dihybrid cross, two traits are considered, each with two alleles. The result is a 4x4 Punnett square with 16 possible genotypes. Homozygous refers to having two identical alleles for a trait. The four homozygous combinations are: RRYY, rrYY, RRyy, and rryy. These combinations reflect both traits being homozygous, either dominant or recessive.Options B, C, and D are incorrect because they do not represent the correct number of homozygous offspring that can result from a dihybrid cross. Specifically, three and two are too few, while nine refers to the count of genotypes rather than homozygous ones.

Q51. In the human beings, the carrier of color blind is:

• A. Male
• B. Female✓
• C. Both male and female
• D. None of them

Explanation: Color blindness is an X-linked recessive trait, meaning it is carried on the X chromosome. Females, having two X chromosomes, can be carriers if they have one normal and one affected X chromosome. They usually do not express the trait unless both X chromosomes carry the gene for color blindness, which is rare. Males, with one X and one Y chromosome, will express the trait if their single X chromosome carries the gene, thus they cannot be carriers. Therefore, the carrier of color blindness is typically female, as only they can carry one affected and one unaffected X chromosome without expressing the trait.

Q52. The number of ATP formed directly by a single Krebs cycle is:

• A. One ATP✓
• B. Two ATP
• C. 32 ATP
• D. 36 ATP

Explanation: The Krebs cycle, also known as the citric acid cycle, occurs in the mitochondria and is a critical part of cellular respiration. During each cycle, it directly produces one ATP (or GTP, which is energetically equivalent to ATP). Since the complete oxidation of one glucose molecule requires two turns of the Krebs cycle, two ATP molecules are formed per glucose molecule. The other options refer to the total ATP yield from the entire process of cellular respiration, not just the Krebs cycle. Thus, the correct answer is that a single Krebs cycle directly forms one ATP.

Q53. Myoglobin combines with:

• A. Four oxygen molecules
• B. Three oxygen molecules
• C. Two oxygen molecules
• D. One oxygen molecule✓

Explanation: Myoglobin is a protein found in muscle tissues with a tertiary structure comprising a single polypeptide chain. This structure allows it to bind with only one oxygen molecule. In contrast, hemoglobin, which is found in the blood, has a quaternary structure with four polypeptide chains, enabling it to bind with four oxygen molecules. Thus, myoglobin's ability to bind with only one oxygen molecule is due to its simpler structure compared to hemoglobin.

Q54. Sunken stomata are present in:

• A. Hydrophytes
• B. Xerophytes✓
• C. Mesophytes
• D. All of the above

Explanation: Sunken stomata are a characteristic adaptation found in xerophytes, which are plants adapted to dry, arid environments. This adaptation helps reduce water loss by protecting the stomata from direct exposure to the air, thereby minimizing transpiration. Hydrophytes, on the other hand, have adaptations suitable for water-rich environments and do not need to conserve water in the same way. Mesophytes live in environments with moderate water supply and do not have sunken stomata. Therefore, the correct answer is xerophytes.

Q55. Which blood group transfusion can be made without risk?

• A. Group A to Group B
• B. Group AB to Group O
• C. Group A to Group O
• D. Group B to Group AB✓

Explanation: Blood transfusions must be compatible, meaning donor blood antigens should not react with recipient blood antibodies. Group AB individuals are universal recipients because they lack antibodies against A and B antigens. Therefore, Group B blood can be safely transfused to Group AB recipients. In contrast, Group A to Group B, Group AB to Group O, and Group A to Group O transfusions all involve antigen-antibody reactions that cause incompatibility and risk.

Q56. Haemophilia affects males than females because of:

• A. X linked recessive✓
• B. X linked dominant
• C. Dominant autosomes
• D. Y linked inheritance

Explanation: Haemophilia is an X-linked recessive disorder, which means it is more commonly seen in males than females. This is because the gene responsible for haemophilia is located on the X chromosome. Males have one X chromosome and one Y chromosome, while females have two X chromosomes. If a male inherits the faulty gene on his X chromosome, he will have haemophilia because he does not have another X chromosome to compensate for the faulty gene. Females, on the other hand, have two X chromosomes, so even if one X chromosome carries the faulty gene, the other X chromosome can often compensate for it. That's why haemophilia is more prevalent in males.

Q57. Penicillin is obtained from:

• A. Penicillium notatum✓
• B. Aspergillus fumigatus
• C. Aspergillus flavus
• D. Penicillium chrysogenum

Explanation: Penicillium notatum is the fungus from which Alexander Fleming first isolated penicillin in 1928, marking a groundbreaking advancement in the treatment of bacterial infections. While Penicillium chrysogenum is used in industrial production today due to its higher yield of penicillin, Penicillium notatum remains historically important for its initial role in antibiotic discovery. Aspergillus fumigatus and Aspergillus flavus are unrelated to penicillin production, with the former being a pathogen and the latter a producer of harmful toxins.

Q58. Insulin is produced by:

• A. Alpha-cells
• B. Beta-cells✓
• C. Delta-cells
• D. Gamma-cells

Explanation: Insulin is produced by Beta cells, which are found in the islets of Langerhans in the pancreas. These cells play a critical role in regulating blood sugar levels by releasing insulin in response to high blood glucose. Alpha cells, on the other hand, produce glucagon, which increases blood sugar levels. Delta cells secrete somatostatin, which has an inhibitory effect on both Alpha and Beta cells. Gamma cells produce pancreatic polypeptides and are not involved in insulin production.

Q59. Chlorophyll a and b chiefly absorb:

• A. Violet blue light
• B. Orange light
• C. Blue—red light✓
• D. Red, orange light

Explanation: Chlorophyll a and b primarily absorb blue and red light. Blue light, being high in energy, excites electrons to a higher energy level, while red light boosts electrons to a lower energy level compared to blue light. Green light is not absorbed but rather reflected, giving plants their green color.

Q60. The following nasal passages are composed of cartilage except:

• A. Trachea
• B. Bronchus
• C. Bronchioles✓
• D. Tracheoles

Explanation: The correct answer is Bronchioles. Bronchioles do not contain cartilage, unlike the trachea and bronchi, which have cartilage to maintain their structure. Instead, bronchioles rely on smooth muscle to regulate airflow. The trachea and bronchus need the structural support provided by cartilage rings to prevent collapse during respiration. The option of tracheoles refers to insect anatomy, which is irrelevant in the context of human respiratory anatomy.

Q61. A set of xylem tissues are:

• A. Vessels, tracheids, parenchyma✓
• B. Sieve tubes, companion cells, fibers
• C. Parenchyma, sieve tube, vessels
• D. Fibers, companion cells, tracheids

Explanation: Xylem tissue is primarily responsible for water transport in plants and consists of four main components: tracheids, vessels, parenchyma, and fibers. Option A correctly lists these components. The other options include elements that belong to phloem tissue, such as sieve tubes and companion cells, which are involved in the transport of nutrients.

Q62. The interval of pacemaker signals from S.A.N to A.V.N is:

• A. 1 second
• B. 0.1 second✓
• C. 2 seconds
• D. 0.2 second

Explanation: The sinoatrial node (SAN) initiates the heartbeat and sends signals to the atrioventricular node (AVN) with a delay of about 0.1 second. This delay is crucial for allowing the ventricles time to fill with blood after the atria contract, ensuring efficient cardiac function. The other time intervals suggested are either too long or too short, disrupting this critical timing and potentially leading to inefficient cardiac performance.

Q63. A Test cross is:

• A. Tt × Tt
• B. Tt × tt✓
• C. TT × Tt
• D. TT × TT

Explanation: The correct answer is Tt × tt. A test cross is used to determine the genotype of an individual displaying a dominant trait by crossing it with an individual that is homozygous recessive (tt). If the unknown genotype is heterozygous (Tt), the offspring will show a 1:1 ratio of dominant to recessive phenotypes. If the unknown genotype were homozygous dominant (TT), all offspring would display the dominant phenotype. Options A, C, and D do not fulfill the requirement of involving a homozygous recessive genotype.

Q64. Carotenoid contains:

• A. Carotenes
• B. Xanthophylls
• C. Chlorophyll – C
• D. Both (A) and (B)✓

Explanation: The carotenoids are divided into two main classes: carotenes and xanthophylls. Carotenes are pure hydrocarbons, meaning they consist only of carbon and hydrogen. Xanthophylls are similar to carotenes but have one or more oxygen atoms in their structure. Although both are types of carotenoids, chlorophylls, such as chlorophyll – C, are not related to carotenoids but are rather a different group of pigments involved in photosynthesis. Therefore, the correct answer is that carotenoids contain both carotenes and xanthophylls.

Q65. The attraction of water molecules to the xylem vessels is called:

• A. Adhesion✓
• B. Cohesion
• C. Collision
• D. Corrosion

Explanation: The correct answer is Adhesion. Adhesion describes the attraction between unlike molecules. In the context of xylem vessels, it refers to the attraction between water molecules and the molecules in the walls of the xylem. This interaction helps water move upwards through the plant. Cohesion, on the other hand, describes the attraction between similar molecules, such as water molecules themselves, which assists in maintaining a column of water inside the xylem. Collision involves physical interactions that lead to changes in motion, which is not applicable here. Corrosion is a chemical process affecting metals, not relevant to plant physiology.

Q66. Tobacco is a:

• A. Long day plant
• B. Short day plant✓
• C. Day-neutral plant
• D. Intermediate plant

Explanation: Tobacco is classified as a short-day plant. These plants require long periods of darkness and shorter daylight hours to initiate flowering. This characteristic is typical in plants that flower in early spring or autumn. On the contrary, long-day plants require longer daylight hours to flower, day-neutral plants do not depend on photoperiods for flowering, and intermediate plants have varying requirements not strictly tied to day length.

Q67. Ripening of fruits can be promoted by:

• A. Gibberellic acid
• B. Indole acetic acid
• C. Flsrcen
• D. Ethylene gas✓

Explanation: Ethylene gas is known as the 'ripening hormone' because it initiates the ripening process in fruits. It causes changes such as increased respiration rate, conversion of starches to sugars, and softening of the fruit cell walls, making the fruit sweeter and more palatable. On the other hand, gibberellic acid focuses on growth processes like stem elongation, indole acetic acid is involved in general plant growth, and 'Flsrcen' is not a valid term in plant biology.

Q68. The diameter of the human capillary is:

• A. 5 microns
• B. 6 microns
• C. 7 microns
• D. 8 microns✓

Explanation: The correct answer is 8 microns. Human capillaries typically have a diameter of about 8 to 10 microns, which is just enough to allow red blood cells to move through them in single file. The endothelial cells that form the capillary walls are crucial for their function. Options A, B, and C represent diameters that are too small for typical capillary function, as they would restrict the movement of red blood cells.

Q69. The least toxic excretory product is:

• A. Ammonia
• B. Urea
• C. Uric acid✓
• D. Fatty acid

Explanation: Option C is correct.The correct answer is uric acid, which is the least toxic excretory product. It is excreted in a solid or semi-solid form and conserves water, making it ideal for animals like birds and reptiles living in arid environments. Ammonia, on the other hand, is highly toxic and requires a significant amount of water to be safely excreted, which is why it is typically excreted by aquatic animals. Urea is less toxic than ammonia and is excreted by mammals and amphibians, requiring moderate amounts of water. Fatty acids are not directly involved in nitrogenous waste excretion.

Q70. Organisms phenotypically similar but genotypically different are said to be:

• A. Monozygous
• B. Homozygous
• C. Heterozygous✓
• D. Multizygous

Explanation: Heterozygous organisms possess two different alleles for a specific trait, which allows them to exhibit similar phenotypes (observable characteristics) despite having different genotypes (genetic makeup). This is why they are phenotypically similar but genotypically different. The other options are incorrect because:Monozygous: Relates to organisms from a single zygote and does not address phenotypic or genotypic differences.Homozygous: Implies both phenotypic and genotypic similarities due to identical alleles.Multizygous: Is not a recognized term relevant to the concept of phenotypic similarity and genotypic difference.

Q71. Gibberellin was isolated from:

• A. An algae
• B. A fungus✓
• C. A bacterium
• D. A virus

Explanation: The correct answer is that gibberellins were first isolated from a fungus, specifically Gibberella fujikuroi. This fungus is known for causing the 'foolish seedling' disease in rice, which results in excessive elongation of the plant. Algae, bacteria, and viruses do not produce gibberellins and are therefore incorrect choices for this question.

Q72. The process of bone formation is called:

• A. Calcification
• B. Chondrification
• C. Decalcification
• D. Ossification✓

Explanation: Ossification is the correct term for the process of bone formation, also known as osteogenesis. It involves the transformation of cartilage or fibrous tissue into bone, a process that begins in the embryonic stage and continues until early adulthood. Calcification, although it involves calcium, pertains to the deposition of calcium salts and not the creation of bone tissue. Chondrification is the process by which cartilage is created, not bone. Decalcification is the removal of calcium, which is contrary to the formation of bone.

Q73. The Bicep muscle is attached to the humerus by:

• A. Tendon✓
• B. Ligaments
• C. Elastic fibers
• D. Areolar

Explanation: The correct answer is 'Tendon'. Tendons are strong bands of connective tissue that connect muscles, like the bicep, to bones such as the humerus. This connection allows the muscle to exert force on the bone, enabling movement. Ligaments, on the other hand, connect bones to other bones and are not involved in muscle attachment. Elastic fibers provide elasticity to tissues but are not involved in the attachment of muscles to bones. Areolar tissue provides loose support and binding between tissues but does not serve the function of attaching muscles to bones.

Q74. The concentration of water molecules is inversely proportional to the:

• A. Water potential
• B. Pressure potential
• C. Solute potential✓
• D. Osmotic potential

Explanation: The correct answer is Solute potential. The concentration of water molecules is inversely proportional to solute potential because when solute concentration increases, it lowers the water potential, thus decreasing the concentration of free water molecules. Water moves from areas of higher water potential (lower solute concentration) to areas of lower water potential (higher solute concentration), which is the principle of osmosis. Water potential encompasses solute potential, but it also includes pressure potential, which is not directly related to solute concentration. Therefore, the direct inverse relationship is with solute or osmotic potential.

Q75. The target organ for vasopressin is:

• A. Heart
• B. Liver
• C. Stomach
• D. Kidneys✓

Explanation: Vasopressin, also known as antidiuretic hormone (ADH), plays a crucial role in maintaining the body's water balance. It acts primarily on the kidneys, increasing the permeability of the kidney tubules to water, thereby promoting water reabsorption and reducing urine output. This helps to concentrate the urine and conserve water in the body. The other options are not directly influenced by vasopressin: the heart is involved in circulation, the liver in metabolism, and the stomach in digestion.

Q76. Thirst is controlled by:

• A. Pituitary gland✓
• B. Adrenal gland
• C. Parathyroid
• D. Thyroid

Explanation: The pituitary gland, specifically through the release of antidiuretic hormone (ADH), plays a crucial role in managing the body's water balance. When hydration levels are low, the pituitary gland secretes ADH to retain water by concentrating urine. This mechanism helps control thirst by signaling the body to conserve water. The adrenal gland, although important for stress and metabolism, does not control thirst. Similarly, the parathyroid glands manage calcium levels, and the thyroid gland regulates metabolism, neither of which are directly involved in thirst regulation.

Q77. Auxins inhibit the growth of:

• A. Apical buds
• B. Lateral buds✓
• C. Parthenocarpy
• D. Root growth

Explanation: Auxins are plant hormones that play a crucial role in regulating plant growth processes. They are primarily known for promoting the growth of the apical bud while inhibiting the growth of lateral buds, a phenomenon known as apical dominance. This is why they inhibit the growth of lateral buds, as the plant directs more resources to the elongation of the main stem. In contrast, auxins promote root growth at low concentrations and can encourage parthenocarpy in some plants. Therefore, the correct answer is that auxins inhibit the growth of lateral buds.

Q78. Redox action takes place during the process of:

• A. Respiration
• B. Photosynthesis
• C. Growth
• D. Both A and B✓

Explanation: Redox reactions are crucial in both respiration and photosynthesis. In respiration, glucose is oxidized to produce energy, and oxygen is reduced to form water. In photosynthesis, water is oxidized, and carbon dioxide is reduced to form glucose. Therefore, both processes fundamentally rely on redox reactions, making Option D the correct choice. Growth, while essential for living organisms, does not primarily involve redox reactions, making Option C incorrect.

Q79. How many genotypes will be produced by crossing two alleles "A" and "a"?

• A. One
• B. Two
• C. Three✓
• D. Four

Explanation: When crossing two alleles 'A' and 'a', the potential genotypes that can be formed are AA, Aa, and aa. This results in three distinct genotypes. Options 'One' and 'Two' are incorrect because they underestimate the number of combinations. Option 'Four' is incorrect because it overestimates the number of possible genotypes.

Q80. A bacterium that converts NO2 to NO3 is:

• A. Rhizobium
• B. Bacillus
• C. Nitrosomonas
• D. Nitrobacter✓

Explanation: Nitrobacter is the correct answer because it is involved in the second step of nitrification, where it converts nitrite (NO2) to nitrate (NO3). This is an essential step in the nitrogen cycle, making nitrogen available to plants in a more accessible form. Rhizobium is involved in nitrogen fixation, Bacillus is known for endospore production, and Nitrosomonas converts ammonia to nitrite, not nitrite to nitrate.

Q81. Methanoic acid HCOOH has one carbon-oxygen bond of length 123 PM and another of 136 PM. The C = O and C-O bond lengths respectively would be:

• A. 136 PM, 123 PM
• B. 123 PM and 136 PM✓
• C. 136 PM, 136 PM
• D. 123 PM and 123 PM

Explanation: The correct answer is 123 PM for the C = O bond and 136 PM for the C-O bond. In organic chemistry, the C = O bond is typically a double bond and therefore shorter due to the increased overlap of the orbitals, which leads to a bond length around 123 PM. On the other hand, the C-O bond is usually a single bond, resulting in a longer bond length of about 136 PM. This is consistent with the typical structures observed in carboxylic acids like methanoic acid. Option A is incorrect because it reverses these lengths. Option C is incorrect because it suggests both bonds are 136 PM, which is not typical for methanoic acid. Option D suggests both bonds are 123 PM, which is also incorrect as it implies both bonds are double bonds, which is not possible in this molecule.

Q82. Choose the compound in which hydrogen bonding is not possible:

• A. H2O
• B. HCl
• C. CH3COOH
• D. CH3OCH3✓

Explanation: Due to the presence of methyl groups that bounds to oxygen there is less tendency of hydrogen bonding in ethers.Also, it does not have hydrogen attached to oxygen, so it cannot form hydrogen bonds with itself.The carboxylic acid, alcohol and water being polar show H-bonding. Option A is correct.

Q83. Benzene undergoes substitution reactions more easily than addition reactions because:

• A. of its cyclic nature
• B. of having three double bonds
• C. of aromatic character
• D. of delocalization of electrons✓

Explanation: The correct answer is that benzene undergoes substitution reactions more easily due to the delocalization of electrons. Benzene's electrons are spread over the entire ring structure, contributing to its remarkable stability, known as aromatic stability. This stability makes it less favorable for benzene to undergo addition reactions, which would disrupt the delocalized electron cloud. Instead, benzene prefers substitution reactions, which maintain its stable aromatic structure.Other options are incorrect because: the cyclic nature (Option A) and three double bonds (Option B) are structural features but not the main reasons for reactivity preference. The aromatic character (Option C) contributes to stability but doesn't directly explain substitution preference; it's the specific electron delocalization that does.

Q84. The ring test is shown by compounds having:

• A. Sulphate radical
• B. Chloride radical
• C. Nitrate radical✓
• D. None of the above

Explanation: The brown ring test is a qualitative analysis technique used to detect the presence of nitrate ions. When a solution containing nitrate ions is treated with freshly prepared ferrous sulfate and then carefully added to concentrated sulfuric acid, a brown ring forms at the interface between the two layers. This indicates the presence of the nitrate radical. Sulphate and chloride radicals do not produce such a ring. The sulphate radical is typically detected by forming a white precipitate with barium chloride, while the chloride radical forms a white precipitate with silver nitrate.

Q85. Which is the strongest acid?

• A. CH3COOH
• B. CH2ClCOOH
• C. CHCl2COOH
• D. CCl3COOH✓

Explanation: The acidity of a carboxylic acid is influenced by the presence of substituents that can stabilize the carboxylate ion. Electron-withdrawing groups, such as chlorine atoms, help stabilize the negative charge by dispersing it, thereby increasing acidity.In this question, CCl3COOH is the strongest acid because it has three chlorine atoms, which are highly effective electron-withdrawing groups. This makes the molecule more acidic than the others, which have fewer chlorine atoms or electron-donating groups like the methyl group in CH3COOH.

Q86. Ozone is:

• A. Greenish, tasteless, light gas
• B. Blue-green, and bitter in taste
• C. Blue, poisonous, and explosive gas
• D. Purple-yellow, poisonous, and nonexplosive gas✓

Explanation: Ozone (O3) is a gas composed of three oxygen atoms. It is often recognized by its pale blue color and is known to be toxic when inhaled, as it can damage lung tissue. Although ozone is a reactive gas, it is not considered explosive under standard conditions. The other options incorrectly describe ozone's appearance or properties, such as explosiveness or taste, which are not applicable to ozone.

Q87. Rectified spirit is:

• A. 100% ethanol
• B. 95% ethanol✓
• C. 90% ethanol
• D. 35% ethanol

Explanation: Rectified spirit, also known as neutral spirits, is a high-purity ethanol solution that has undergone multiple distillation processes known as rectification to reach a concentration of 95% ethanol and 5% water. This specific ratio allows it to be used effectively in applications requiring high-purity alcohol. Option A (100% ethanol) is incorrect because absolute ethanol does not contain any water, making it distinct from rectified spirit. Option C (90% ethanol) contains more water than rectified spirit, altering its properties and uses. Option D (35% ethanol) is far too diluted and is not used in contexts where rectified spirit is required.

Q88. Lucas Test is used to detect the presence of:

• A. Alcohols✓
• B. Phenols
• C. Amino acids
• D. Carboxylic acids

Explanation: The Lucas test is a chemical test used to differentiate between primary, secondary, and tertiary alcohols. It involves the use of Lucas reagent (a mixture of concentrated hydrochloric acid and zinc chloride). Tertiary alcohols react immediately, secondary alcohols react within a few minutes, and primary alcohols do not react at room temperature. Therefore, the correct answer is alcohols. Phenols, amino acids, and carboxylic acids are not detected using the Lucas test; they require different tests for identification.

Q89. Choose the correct statement:

• A. The human body does not produce enzymes
• B. The human body does not produce vitamins✓
• C. Proteins are an energy source for our body
• D. Nucleic acids are building blocks for our body

Explanation: The correct answer is that the human body does not produce vitamins. Vitamins are essential nutrients that must be obtained from the diet because the body either lacks the enzymes to synthesize them or cannot produce them in adequate amounts. Option A is incorrect because enzymes are produced by the body to catalyze biochemical reactions. Option C, while acknowledging that proteins can be used for energy, fails to recognize their primary role in growth and repair. Option D is incorrect because nucleic acids are not building blocks; they store and transfer genetic information.

Q90. Na2B4O7 10 H20 is the formula of:

• A. Bauxite
• B. Borax✓
• C. Carborundum
• D. Colemanite

Explanation: The compound Na2B4O7 10 H2O is known as Borax. It is a naturally occurring mineral and a common household cleaning agent. The formula represents sodium tetraborate decahydrate. Bauxite is an aluminum ore, Carborundum is silicon carbide, and Colemanite is a borate mineral with a different formula. Therefore, the correct answer is Borax.

Q91. 1 amu is equal to 1.661 × 10-24g, then 1.0 g will be equal to:

• A. 6.022 × 10^23 amu✓
• B. 6.022 × 10^-23 amu
• C. 6.022 × 10^-24 amu
• D. 6.022 × 10^24 amu

Explanation: As 1 a.m.u is equal to 1.66 x 10^-24 g conversely 1 gram is equal to 6.022 x 10^23 amu.For example: 1 carbon atom = 12 amu 1 mole of carbon = 12 g6.022 x 10^23 C atom = 12 g1 C atom / 12 = 1 amu6.022 x 10^23 C atom / 12 = 6.022 x 10^ 23 amu As written above: 6.022 x 10^23 = 12g, we will right like that, 12g/12 = 6.022 x 10^23Hence , 1g = 6.022 x 10^23

Q92. For a certain chemical reaction, the slope of the plot was determined and plotted against the concentration (a-x)2 and a straight line was obtained. It indicates that the reaction is of:

• A. First order
• B. Second order✓
• C. Third order
• D. Zero order

Explanation: For a second-order reaction, dx / dt = k(a−x)2Ploting dx / dt vs (a−x)2Give straight line

Q93. One mole is the amount of substance that contains as many elementary entities as contained in:

• A. 0.12 kg of 6C12
• B. 1.2 kg of 6C12 atom
• C. 0.012 kg of 6C12 atom✓
• D. 0.12 kg of 8O16

Explanation: One mole is defined as the amount of substance containing as many elementary entities (atoms, molecules, etc.) as there are atoms in 12 grams of the carbon-12 isotope. This is also known as Avogadro's number, approximately 6.022 x 1023 entities. The correct option, 0.012 kg of 6C12, is a simple conversion of 12 grams to kilograms, aligning with the standard definition of a mole. The other options either use incorrect masses or a different isotope, which do not fit the definition based on carbon-12.

Q94. Select the chemical method used for the determination of the reaction rate:

• A. Conductometry
• B. Polarimetry
• C. pH meter
• D. Volumetric analysis✓

Explanation: Volumetric analysis is specifically designed to measure concentration changes in a reaction over time, making it ideal for determining reaction rates. Unlike conductometry, which relates to ionic conductivity, polarimetry, which involves optical properties, and pH meters, which assess acidity levels, volumetric analysis provides a direct measure of how concentrations of reactants or products change, directly correlating to reaction rates.

Q95. Bakelite is obtained from:

• A. Adipic acid and hexamethylenediamine
• B. Dimethyl terephthalate and ethylene glycol
• C. Neoprene
• D. Phenol and formaldehyde✓

Explanation: Bakelite is a thermosetting polymer formed from the condensation reaction of phenol and formaldehyde. This reaction creates a hard, heat-resistant material used in electrical insulators and other products. The other options involve different chemicals used to make different types of polymers: nylon, PET, and neoprene.

Q96. Consider the following endothermic reaction: N2(g) + O2(g) → 2NO(g). What will happen to the equilibrium if the temperature of the system is raised?

• A. The equilibrium will shift in the backward direction
• B. The equilibrium position will remain unchanged
• C. The equilibrium will shift in the forward direction✓
• D. All of the above

Explanation: In an endothermic reaction such as N2(g) + O2(g) → 2NO(g), increasing the temperature provides additional heat that the system can absorb. According to Le Chatelier's principle, the system will adjust by favoring the forward reaction (towards the products) to absorb this extra heat. This results in increased production of NO and a higher equilibrium constant (Kc). Option A is incorrect because a backward shift occurs when temperature is decreased. Option B is incorrect because temperature changes do affect equilibrium. Option D is incorrect because the options cannot all be correct simultaneously.

Q97. Why it is so that if aromatic compounds are burned In the air, produce a very smoky flame?

• A. An aromatic compound cannot be completely converted into CO2 and other products during burning
• B. The available amount of oxygen present in the air is not sufficient to completely burn the available compound✓
• C. Aromatic compounds produce compounds on burning that are of black color
• D. None of the above

Explanation: Aromatic compounds produce a smoky flame when burned due to their high carbon content. The combustion process requires more oxygen than is typically available in the air to completely convert all carbon into carbon dioxide. Without sufficient oxygen, incomplete combustion occurs, resulting in unburnt carbon particles that give the flame its smoky appearance.Option B is correct because it captures the need for adequate oxygen to complete the combustion of carbon in aromatic compounds. Option A touches on incomplete conversion but does not explain the oxygen requirement. Option C incorrectly attributes the smoky appearance to specific compounds rather than unburnt carbon. Option D is incorrect because the correct explanation is provided in Option B.

Q98. Acetic acid reacts with methyl alcohol in the presence of acid catalyst to give:

• A. Ethyl formate
• B. Ethyl acetate
• C. Methyl formate
• D. Methyl acetate✓

Explanation: This is the correct product formed by the reaction between acetic acid and methyl alcohol in the presence of an acid catalyst. The reaction is an esterification reaction, where the -OH group of acetic acid reacts with the -OH group of methyl alcohol to form water and methyl acetate.

Q99. Select the strongest reducing agent:

• A. Cl^-
• B. Ne
• C. Na
• D. Ca✓

Explanation: The correct answer is Ca. Calcium, as a metal, has a low electronegativity and readily donates electrons, making it a strong reducing agent. It easily loses two electrons to form Ca^2+, thereby achieving a stable electronic configuration.In contrast, the chloride ion (Cl^-) tends to gain electrons, acting as an oxidizing agent. Neon (Ne) is inert due to its full valence shell, making it unlikely to participate in electron transfer. Sodium (Na), although it can lose an electron, is not as strong a reducing agent as calcium due to its higher electronegativity.

Q100. CH4 on complete oxidation in the presence of Cu as catalyst under 200 atm yield:

• A. Methanol✓
• B. Formaldehyde
• C. Formic acid
• D. Carbon dioxide gas

Explanation: The complete oxidation of methane in the presence of a copper catalyst at high pressure (200 atm) leads to the formation of methanol. This is due to controlled oxidative conditions that favor the formation of methanol rather than proceeding to full combustion, which would result in carbon dioxide and water.Option A is correct because methanol is the target product under the given reaction conditions. Option B is incorrect as formaldehyde is an intermediate oxidation product of methanol, not directly from methane. Option C is incorrect as formic acid results from further oxidation of formaldehyde. Option D is incorrect because carbon dioxide forms from complete combustion, not the controlled oxidation process described.

Q101. The solids in which the molecules or ions are arranged in a regular repetitive manner are called:

• A. Amorphous solids
• B. Glassy solids
• C. Polymers
• D. Crystals✓

Explanation: Crystals are characterized by a precise and repeating lattice structure that extends in all three spatial dimensions, resulting in a highly ordered arrangement of particles. This is contrasted with amorphous solids and glassy solids, which do not exhibit such order. Polymers may show some degree of order but are not typically organized in a repeating three-dimensional lattice like crystals.

Q102. Compared to benzene, nitration of toluene takes place at:

• A. slower rate
• B. faster rate✓
• C. same rate
• D. depends on the conditions

Explanation: Compared to benzene, nitration of toluene occurs at a faster rate due to the presence of the methyl group (-CH3), which is an electron-donating group. This group activates the benzene ring by hyperconjugation and directs electrophilic substitution to the ortho and para positions, increasing the reactivity of the ring towards nitration. The other options are incorrect because they either overlook the activating effect of the -CH3 group or suggest that the reaction rate is condition-dependent, which is not the case here.

Q103. Sodium hydroxide acts on Aluminum oxide to form:

• A. NaAlO3
• B. Na3Al2O6
• C. NaAlO2✓
• D. NaAl2O3

Explanation: The reaction between sodium hydroxide (NaOH) and aluminum oxide (Al2O3) results in the formation of sodium aluminate (NaAlO2) and water. The chemical equation for this reaction is:2 NaOH + Al2O3 → 2 NaAlO2 + H2OOption C is correct because it represents the correct formula for sodium aluminate. Options A, B, and D are incorrect because they do not accurately reflect the products of this typical reaction.

Q104. The alpha bond formed between carbon and oxygen atoms in aldehyde and ketone is due to the overlap of:

• A. sp2 — sp
• B. sp2 — sp2✓
• C. sp3 — sp2
• D. sp — sp

Explanation: The correct answer is sp2 — sp2. In aldehydes and ketones, the carbonyl carbon atom is sp2 hybridized. It forms a sigma bond with the oxygen atom through the overlap of their sp2 hybrid orbitals. This sp2 hybridization accounts for the planar structure of the carbonyl group. Other options are incorrect because they either involve different hybridizations that do not match the structure of aldehydes and ketones or do not apply to the carbonyl group.

Q105. Paper is a biodegradable material. It produces gas whose emission is environmentally objectionable. Which is that gas?

• A. CO2✓
• B. SO2
• C. CH4
• D. NO2

Explanation: When paper biodegrades, especially in the presence of oxygen, the primary gas emitted is carbon dioxide (CO2), due to the aerobic decomposition of its cellulose content. This process involves microorganisms breaking down the organic matter, releasing CO2 as a byproduct. Other gases like sulfur dioxide (SO2), methane (CH4), and nitrogen dioxide (NO2) are not typically emitted during the biodegradation of paper. SO2 is linked to burning sulfur-containing materials, CH4 is released in anaerobic conditions like landfills, and NO2 results from high-temperature combustion processes of fossil fuels.

Q106. How many sigma bonds are there in CH2 = CH – CH = CH2

• A. 6
• B. 9✓
• C. 11
• D. 4

Explanation: The molecule CH2=CH–CH=CH2 consists of four carbon atoms and four hydrogen atoms. Each carbon atom forms single sigma bonds with hydrogen atoms:The first carbon (CH2) forms 2 sigma bonds with hydrogen.The second carbon (CH) forms 1 sigma bond with hydrogen.The third carbon (CH) forms 1 sigma bond with hydrogen.The fourth carbon (CH2) forms 2 sigma bonds with hydrogen.Additionally, each double bond consists of one sigma bond and one pi bond between adjacent carbon atoms:There are 3 carbon-carbon sigma bonds in the molecule (one for each pair of adjacent carbon atoms).Adding all the sigma bonds together, we have 2 + 1 + 1 + 2 (from C-H) + 3 (from C-C) = 9 sigma bonds in total.Options 6, 11, and 4 are incorrect because they either underestimate or overestimate the number of sigma bonds by not accurately accounting for all the bonds present in the molecule.

Q107. The cracking problem of fuel combustion can be avoided by:

• A. Reforming
• B. Improving octane number
• C. Adding TEL
• D. All of the above✓

Explanation: Option D is correct because reforming, improving the octane number, and adding TEL are all methods that help reduce knocking and improve engine performance by increasing the octane number. Reforming and adding TEL directly increase the octane rating, leading to smoother fuel combustion. Option A only covers reforming, Option B focuses solely on octane number improvement, and Option C only mentions the use of TEL. Each method individually contributes to the solution, but all together, they comprehensively address the problem of cracking in fuel combustion.

Q108. Select the compound that will give a Positive iodoform test:

• A. Benzaldehyde
• B. 2-Pentanone✓
• C. 3-Hexanone
• D. 3-Pentanone

Explanation: The iodoform test is a chemical reaction used to identify methyl ketones, which contain a CH3 group directly bonded to the carbonyl carbon. 2-Pentanone is the only compound among the options that has this structure, allowing it to undergo the necessary halogenation and subsequent hydrolysis to form iodoform (CHI3), which is a yellow precipitate. Benzaldehyde, 3-Hexanone, and 3-Pentanone do not have the requisite alpha-methyl group, and therefore, do not give a positive iodoform test.

Q109. Ethene and Ethyne can be distinguished by employing the test:

• A. Br2 in organic solvent
• B. Baeyer‘s reagent
• C. Phenyl Hydrazine
• D. Tollen‘s reagent✓

Explanation: The correct answer is Tollen’s reagent. Ethene does not react with Tollen's reagent, whereas Ethyne reacts with it to form a white precipitate of silver acetylide, allowing for their differentiation. Br2 in an organic solvent cannot distinguish between Ethene and Ethyne as both will decolorize the solution. Baeyer’s reagent (dilute KMnO4) reacts with Ethene but not significantly with Ethyne under the same conditions, requiring stronger conditions for Ethyne. Phenyl Hydrazine does not react with either compound, making it ineffective for distinction.

Q110. Which is true about London forces?

• A. London forces are present in non-polar molecules.
• B. London forces are present in polar molecules.
• C. London forces are created between an instantaneous dipole and an induced dipole.
• D. All of the above.✓

Explanation: London dispersion forces are a type of van der Waals force and are the weakest intermolecular force. They are present in all molecules, regardless of polarity. These forces are more significant in non-polar molecules because they are the only type of intermolecular force present. In polar molecules, dipole-dipole interactions are stronger, but London forces still exist. London forces occur due to the temporary and instantaneous dipoles that arise from electron movement, which can induce a dipole in a neighboring particle, leading to an attraction. Therefore, the correct answer is 'All of the above' because each statement highlights a true aspect of London forces.

Q111. The correct electronic configuration of Nickel (28) is:

• A. 1s2 2s2 2p6 3s2 3p6 3d8 4s2✓
• B. 1s2 2s2 2p6 3s2 3p6 3d7 4s2 4p1
• C. 1s2 2s2 2p6 3s2 3p6 3d6 4s2 4p2
• D. 1s2 2s2 2p6 3s2 3p6 3d6 4s1 4p3

Explanation: The correct electronic configuration for Nickel (28) is 1s2 2s2 2p6 3s2 3p6 3d8 4s2. This order follows the Aufbau Principle, which dictates that electrons occupy the lowest energy orbitals first. Option A adheres to this principle, filling the 3d subshell before moving to higher subshells. Options B, C, and D incorrectly fill higher energy levels before completing the 3d subshell, violating the Aufbau Principle.

Q112. Select the correct equilibrium constant expression, Kc for the following reversible reaction. Ce4+(aq) + Fe2+(aq) → Ce3+(aq) + Fe3+(aq)

• A. Kc = [Ce3+][Fe3+]/[Ce4+][Fe2+]✓
• B. Kc = [Ce3+][Fe2+]/[Ce4+][Fe3+]
• C. Kc = [Ce4+][Fe3+]/[Ce3+][Fe2+]
• D. Kc = [Ce3+][Fe2+][Ce4+][Fe3+]

Explanation: The correct equilibrium constant expression, Kc, for the given reaction is Kc = [Ce3+][Fe3+]/[Ce4+][Fe2+]. This expression is derived by dividing the product of the concentrations of the products (Ce3+ and Fe3+) by the product of the concentrations of the reactants (Ce4+ and Fe2+). Each concentration is raised to the power of its respective stoichiometric coefficient, which in this case are all 1, so they do not alter the expression. Option A correctly reflects these principles. The other options either incorrectly swap reactants and products or fail to apply the division necessary to form the equilibrium constant expression.

Q113. Bohr predicted the radius of the orbit of the electron in the hydrogen atom to be: If the electron moves from n = 1 to n = 2, by how many times the radius of the orbit will increase?

• A. 2 times
• B. 3 times✓
• C. 4 times
• D. 5 times

Explanation: Since r = n^2 (0.053nm) When n = 1 r1 = 0.053nm When n = 2 r2 = 2^2 (r1) r2 = 4 r1 An increase in the radius of orbit when an electron moves from n=1 to n=2 is given as 4r1 - r1 = 3r1 ( 3 times increase)

Q114. The volume occupied by 3.2 g of oxygen at STP is:

• A. 22.4 dm3
• B. 2.24 dm3✓
• C. 11.2 dm3
• D. 16.0 dm3

Explanation: At STP, one mole of any ideal gas occupies 22.4 dm3. The molar mass of oxygen (O2) is 32 g/mol. Therefore, the number of moles in 3.2 g of oxygen is 3.2 g / 32 g/mol = 0.1 moles. The volume occupied by 0.1 moles of oxygen is 0.1 × 22.4 dm3 = 2.24 dm3.Option A represents the full molar volume at STP, not applicable to 3.2 g. Option C is half the molar volume, applicable to 16 g of oxygen, not 3.2 g. Option D does not correlate with any significant fraction of molar volume in this context.

Q115. Which of the following elements with a given electronic configuration has the highest ionization potential value?

• A. 1s2 2s2 2p3✓
• B. 1s2 2s2 2p4
• C. 1s2 2s2 2p6 3s1
• D. 1s2 2s2 2p6 3s2 3p3

Explanation: Ionization energy is the energy required to remove an electron from an isolated gaseous atom. The stability of the electron configuration plays a significant role in determining this energy. Nitrogen, with the configuration 1s2 2s2 2p3, has a half-filled p orbital, which is particularly stable, thus requiring a higher ionization energy. Oxygen (1s2 2s2 2p4) has a partially filled p orbital, making it easier to remove an electron, while sodium (1s2 2s2 2p6 3s1) is highly electropositive with its outermost electron easily removable. Phosphorus (1s2 2s2 2p6 3s2 3p3) also has a half-filled p orbital but is larger in size than nitrogen, resulting in a lower ionization potential. Therefore, nitrogen has the highest ionization potential among the given options.

Q116. Which one is not responsible for the formation of acid rain?

• A. CO2
• B. SO2
• C. CO✓
• D. NO2

Explanation: Acid rain is primarily caused by the dissolution of specific oxides in atmospheric moisture, leading to acidic compounds. Carbon monoxide (CO) is not capable of forming an acid when it reacts with water, thus it does not contribute to acid rain. In contrast, carbon dioxide (CO2) can form carbonic acid, sulphur dioxide (SO2) forms sulphuric acid, and nitrogen dioxide (NO2) forms nitric acid, all of which contribute to acid rain. Therefore, CO is the only option that does not lead to acid rain formation.

Q117. Which of the following hybridization can explain the the shape of BeCl2?

• A. sp2 hybridization
• B. sp hybridization✓
• C. sp3 hybridization
• D. dsp2 hybridization

Explanation: The correct hybridization for BeCl2 is sp, which occurs when there are two electron domains around the central atom. In BeCl2, the beryllium atom forms two bonds with chlorine atoms and has no lone pairs, leading to a linear molecular shape. This is characteristic of sp hybridization, where one s orbital and one p orbital mix to form two equivalent sp hybrid orbitals.The other options are incorrect as:sp2 hybridization: Requires three electron domains, usually resulting in a trigonal planar shape, which does not apply to BeCl2.sp3 hybridization: Involves four electron domains, resulting in a tetrahedral shape, which again is not applicable to BeCl2.dsp2 hybridization: Is typically seen in square planar complexes, not in a simple molecule like BeCl2.

Q118. According to Millikan‘s oil drop experiment, the charge on an oil droplet is:

• A. Quantized
• B. Integral multiple of 'e'
• C. Not less than 'e'
• D. All of the above✓

Explanation: Millikan's oil drop experiment demonstrated that the charge on an oil droplet is quantized, meaning it can only exist in discrete values, which are integral multiples of the elementary charge 'e' (1.6 × 10-19 C). Therefore, the charge cannot be less than 'e', and it is always an integer multiple of 'e'. Each of these statements is a valid description of the charge characteristics, making all options collectively correct. The correct answer is indeed 'All of the above'.

Q119. The enthalpy of the elements at 1 atm: pressure and 298 K is arbitrary given the value of:

• A. 0.1
• B. 1.0
• C. 29.8
• D. Zero✓

Explanation: The correct answer is Zero. In thermodynamics, the standard enthalpy of formation for an element in its most stable form at 1 atm pressure and 298 K is defined as zero. This is a convention used to provide a reference point, as it simplifies the calculation of enthalpy changes for chemical reactions. The other options (0.1, 1.0, and 29.8) do not apply because they do not represent the standard reference state enthalpy.

Q120. Select the correct statement about lattice energy:

• A. The energy absorbed when 1 mole of an ionic crystal lattice is formed from its constituent ions in the gaseous state.
• B. The energy liberated when 1 mole of an ionic crystal lattice is formed from its constituent ions in the gaseous state.✓
• C. The energy liberated when 1 mole of an ionic crystal lattice is split into its constituent ions in the gaseous state.
• D. None of the above

Explanation: Lattice energy refers to the energy change associated with the formation of an ionic solid from its gaseous ions. This process is exothermic, meaning it releases energy. Option B is correct because it accurately describes the process of lattice formation as one that liberates energy. Option A is incorrect because it suggests that energy is absorbed, which describes an endothermic process. Option C is incorrect because it describes the reverse process, where energy would be absorbed to break the lattice apart. Option D is also incorrect because it suggests none of the statements are true, while Option B is accurate.

Q121. Which of the following compounds on treatment with NaHCO3 will liberate CO2?

• A. CH3COOH✓
• B. C2H5NH2
• C. CH3COCH3
• D. CH3CH2OH

Explanation: The correct answer is CH3COOH. Carboxylic acids, such as acetic acid (CH3COOH), react with sodium bicarbonate (NaHCO3) to produce carbon dioxide (CO2), water, and a sodium salt. This reaction is due to the acidic nature of carboxylic acids, which can donate a proton to the bicarbonate ion. In contrast, ethylamine (C2H5NH2), acetone (CH3COCH3), and ethanol (CH3CH2OH) do not have the acidic hydrogen necessary to react with NaHCO3 and thus do not liberate CO2.

Q122. Commonly used coagulant used for the purification of water is:

• A. Ca(NO3)2
• B. MgCl2
• C. Al2(SO4)3✓
• D. Ca(OH)2

Explanation: In water treatment, coagulants like Al2(SO4)3 (aluminum sulfate) are used to remove impurities by causing them to aggregate for easier removal. This process is essential for removing organic matter, pathogens, and toxic materials. Ca(NO3)2 is a fertilizer, MgCl2 is used for de-icing, and Ca(OH)2 is used for pH adjustment, not as a primary coagulant.

Q123. Which compound is formed when Ammonium hydroxide is added to silver chloride?

• A. [Ag(NH3)2]Cl✓
• B. [Ag(NH3)]Cl
• C. [Ag(NH3)4]Cl
• D. [Ag(NH3)6]Cl

Explanation: When ammonium hydroxide is added to silver chloride, the silver chloride dissolves in the ammonia to form a diamine complex: [Ag(NH3)2]Cl. This occurs because ammonia acts as a ligand, donating a pair of electrons to silver ions, forming a stable complex. The correct option, [Ag(NH3)2]Cl, reflects this complex formation. Other options like [Ag(NH3)]Cl, [Ag(NH3)4]Cl, and [Ag(NH3)6]Cl are incorrect as they suggest incorrect stoichiometries and coordination numbers that do not occur in this reaction.

Q124. Which one is a spontaneous chemical reaction?

• A. Zn + Cu2+ → Zn2+ + Cu✓
• B. Zn2+ + Cu → Cu2+ + Zn
• C. 2 Fe(OH)3 → 2 Fe + 3/2 O2 + 3 H2O
• D. 2NaCl → 2Na + Cl2

Explanation: A spontaneous chemical reaction is one that occurs without continuous external energy input, often characterized by a negative Gibbs free energy change (ΔG). In the reaction Zn + Cu2+ → Zn2+ + Cu, zinc is oxidized while copper ions are reduced, releasing energy in the process, thus making it spontaneous. In contrast, the other reactions are non-spontaneous because they require external energy to proceed. The reaction Zn2+ + Cu → Cu2+ + Zn is the reverse of the spontaneous reaction and requires energy input. The decomposition of Fe(OH)3 and the breakdown of NaCl are both processes that require energy input, hence they are non-spontaneous.

Q125. Which one of the following will give an ionic product?

• A. CH3CH2OH + PCl5 →
• B. CH3CH2OH + Na →✓
• C. CH3CH2OH + PCl3 →
• D. CH3CH2OH + 5OCl →

Explanation: The correct answer is Option B: CH3CH2OH + Na →. In this reaction, sodium (Na), a metal, reacts with ethanol (CH3CH2OH) to form sodium ethoxide (CH3CH2ONa) and hydrogen gas (H2). Sodium ethoxide is an ionic compound, as it consists of the sodium ion (Na+) and the ethoxide ion (CH3CH2O-). This ionic nature is due to the transfer of an electron from sodium to the ethoxide group. The other options involve covalent reactions that do not result in ionic products: Option A involves the formation of alkyl chlorides, Option C involves the substitution of hydroxyl groups by chlorine without forming ionic compounds, and Option D suggests a non-standard reaction.

Q126. Which of the following can function as Lewis acid?

• A. CN-
• B. NH3
• C. CH3 – O – CH3
• D. I+✓

Explanation: The correct answer is I+. A Lewis acid is defined as an electron pair acceptor, and I+ fits this definition because of its positive charge and incomplete octet, making it electron-deficient. This allows it to accept electron pairs from Lewis bases. Other options, such as CN-, NH3, and CH3 – O – CH3, are more likely to donate electron pairs due to their lone pairs or negative charge, making them Lewis bases instead.

Q127. All amino acids found in proteins are:

• A. ɑ-amino acids✓
• B. β-amino acids
• C. Both ɑ and β
• D. None of the above

Explanation: The correct answer is that all amino acids found in proteins are ɑ-amino acids. These are characterized by the presence of the amino group bonded to the alpha carbon, which is the carbon atom directly adjacent to the carboxyl group. This structure is crucial for the formation of peptide bonds during protein synthesis. Although β-amino acids exist in nature, they are not incorporated into proteins. Proteins are specifically constructed from the 22 genetically encoded alpha-amino acids. Therefore, options B, C, and D are incorrect.

Q128. Which is a trimer of ethyne?

• A. PVC
• B. Benzene✓
• C. Toluene
• D. Teflon

Explanation: Benzene is formed by the cyclic trimerization of three ethyne (acetylene) molecules in a chemical process that rearranges the atoms into a stable aromatic ring. Each ethyne molecule contributes two carbon atoms, resulting in the six-carbon structure of benzene. The other options, PVC, toluene, and Teflon, are not formed from ethyne or its derivatives: PVC is derived from vinyl chloride, toluene is a methyl-substituted benzene, and Teflon is a polymer of tetrafluoroethylene.

Q129. Which is NOT true about amino acids?

• A. They have two functional groups
• B. They show both acidic and basic characteristics
• C. They are the basic units of proteins
• D. They do not exist in solid state✓

Explanation: Amino acids exist as zwitterions, which are molecules that have both positive and negative charges but are overall neutral. This zwitterionic form is stable and contributes to strong intermolecular interactions, allowing amino acids to exist in a solid state at room temperature. Option D is incorrect because amino acids do exist in solid state. Option A is true because the amino and carboxyl groups are the two functional groups present in amino acids. Option B is true as amino acids can exhibit both acidic and basic properties. Option C is correct as amino acids are indeed the basic units of proteins.

Q130. Which is the least polar molecule?

• A. HF
• B. HI✓
• C. HCl
• D. HBr

Explanation: To determine the polarity of diatomic molecules, we examine the difference in electronegativity between the two atoms. The smaller the difference, the less polar the molecule. In HI, the electronegativity of hydrogen is 2.2 and that of iodine is 2.66, giving an electronegativity difference of 0.46, which is the smallest among the given options. Therefore, HI is the least polar molecule. Conversely, HF has the largest electronegativity difference, making it the most polar, followed by HCl and HBr, which have intermediate differences.

Q131. Ketones are prepared by the oxidation of:

• A. Primary alcohol
• B. Secondary alcohol✓
• C. Tertiary alcohol
• D. All of the above

Explanation: Ketones are prepared by the oxidation of secondary alcohols. When a secondary alcohol is oxidized, it loses hydrogen atoms and forms a ketone. Primary alcohols, on the other hand, are oxidized to form aldehydes, while tertiary alcohols cannot be oxidized to form ketones or aldehydes. So, it's the secondary alcohols that are used to prepare ketones.

Q132. Which of the following is a condensation polymer?

• A. Nylon 6,6✓
• B. Teflon
• C. Polypropylene
• D. Orlon

Explanation: Condensation polymers are formed through condensation reactions, where two monomers join together with the release of a small molecule like water. Nylon 6,6 is a classic example of a condensation polymer, as it is synthesized from hexamethylenediamine and adipic acid, with water being released. On the other hand, Teflon, polypropylene, and Orlon are all formed through addition polymerization, where monomers add to each other without the loss of any small molecules.

Q133. Which of the following statement is NOT true?

• A. Condyloid joint is triaxial✓
• B. Synovial fluid reduces friction
• C. Coronal suture is for parietal and frontal bone articulation
• D. Synostosis is a bony joint

Explanation: The correct answer is Option A: Condyloid joint is triaxial. Condyloid joints are biaxial, allowing movement in two planes but not rotation, which means they are not triaxial. Examples of condyloid joints include the wrist joint (radiocarpal joint). Option B is true because synovial fluid reduces friction in synovial joints. Option C is also true; the coronal suture connects the parietal and frontal bones. Finally, Option D is correct in stating that synostosis is a bony joint, as it involves the fusion of bones into a single unit.

Q134. The ionization potential of Hydrogen atom is:

• A. 13.6 eV✓
• B. 1.36 eV
• C. 10.2 eV
• D. 4.3 eV

Explanation: The ionization potential of a hydrogen atom is 13.6 eV, which is the energy needed to completely remove the electron from the nucleus when the atom is in its ground state. This value is derived from the Bohr model of the hydrogen atom. Other options like 1.36 eV, 10.2 eV, and 4.3 eV do not match the energy required to ionize hydrogen and are therefore incorrect.

Q135. In which of the following compounds hydrogen bonding is possible?

• A. PH3
• B. CH4
• C. NH3✓
• D. SiH4

Explanation: Hydrogen bonding occurs when hydrogen is bonded to a highly electronegative atom such as nitrogen, oxygen, or fluorine, which creates a significant dipole. In NH3 (ammonia), hydrogen is directly bonded to nitrogen, which is highly electronegative and capable of forming hydrogen bonds with other molecules. The other options, PH3, CH4, and SiH4, involve atoms that are not sufficiently electronegative to facilitate hydrogen bonding.

Q136. Sucrose sugar is considered as:

• A. Monosaccharide
• B. Disaccharide✓
• C. Polysaccharide
• D. All of the above

Explanation: Sucrose is classified as a disaccharide because it is composed of two monosaccharide units: glucose and fructose. Disaccharides are a specific type of oligosaccharide, which typically include sugars that consist of a small number of monosaccharide units. Monosaccharides, such as glucose and fructose, are single sugar molecules, unlike sucrose. Polysaccharides, such as starch, consist of long chains of monosaccharides, which is not the case for sucrose. Therefore, the correct classification for sucrose is a disaccharide.

Q137. Forces controlling the reactions are proportional to the product of the active masses (concentration) of chemicals.The above statement is of:

• A. Raoult‘s Law
• B. Le Chatelier‘s Principle
• C. The law of conservation of energy
• D. The law of mass action✓

Explanation: The correct answer is the law of mass action. This law specifically states that the rate of a chemical reaction is proportional to the product of the concentrations of the reactants, which directly matches the statement given in the question. It is fundamental in determining the equilibrium constant for a reaction. The other options, such as Raoult's Law, Le Chatelier's Principle, and the law of conservation of energy, address different aspects of chemistry like vapor pressures, equilibrium shifts, and energy conservation, none of which are related to the proportional relationship between reaction rates and reactant concentrations.

Q138. The sum of mole fractions of solute and solvent is always equal to:

• A. 0.1
• B. 10.0
• C. 1.0✓
• D. Zero

Explanation: The fundamental concept of mole fractions dictates that the sum of the mole fractions of all components in a solution, including both solute and solvent, must equal 1. This is because mole fraction is a way of expressing the concentration of a component in a mixture, and all component concentrations together must sum to the whole, which is 1.0. Options A, B, and D are incorrect because they do not satisfy this fundamental principle: 0.1 and zero are too low, and 10.0 is too high.

Q139. An Azeotropic mixture of two miscible liquids boils at a lower temperature than its components when:

• A. The system shows a negative deviation from Raoult‘s law.
• B. The system shows a positive deviation from Raoult‘s law.✓
• C. The system perfectly obeys Raoult‘s law
• D. Both (A) and (B)

Explanation: An azeotropic mixture is a combination of liquids that behave as a single substance with a consistent boiling point and consistent vapor and liquid phase compositions at a given pressure. When a system shows a positive deviation from Raoult's law, the intermolecular forces between different components are weaker compared to those in an ideal solution. This results in a lower boiling point as the total vapor pressure is higher than predicted by Raoult's law. Hence, the azeotropic mixture boils at a lower temperature than any of its pure components. In contrast, a negative deviation would indicate stronger intermolecular forces, leading to a higher boiling point.Therefore, Option B is correct because it describes the situation where a positive deviation results in a lower boiling point for the azeotropic mixture.

Q140. The ratio of output voltage V0 to the voltage difference Vin between the positive (+) input and negative (-) input of a pump is (where Vin=V+ – V – :

• A. Current gain
• B. Voltage gain✓
• C. Open-loop gain
• D. Closed-loop gain

Explanation: The correct answer is Voltage gain. It is defined as the ratio of the output voltage (V0) to the input voltage difference (Vin), which matches the description in the question. The other options are incorrect because:Current gain is unrelated to voltage as it concerns the ratio of currents.Open-loop gain describes a scenario without feedback, which is irrelevant to the question’s context.Closed-loop gain involves feedback mechanisms, which are not mentioned in the question.

Q141. The resistance of light dependant resistance LDR:

• A. Increases with light
• B. Decreases with light✓
• C. Decreases with darkness
• D. None of the above

Explanation: The correct answer is that the resistance of a Light Dependent Resistor (LDR) decreases with an increase in light intensity. This is because LDRs are designed to be sensitive to light, thus reducing their resistance as they are exposed to more light. Option A is incorrect because it states the opposite of what actually happens. Option C is misleading as it incorrectly suggests that resistance decreases in darkness, whereas it actually increases. Option D is incorrect as there is a correct statement among the options provided.

Q142. The maximum kinetic energy of an electron ejected from a metal by a photon depends on:

• A. The photon's frequency only
• B. The metal work function and photon's frequency✓
• C. The intensity of incident light
• D. None of the above

Explanation: The maximum kinetic energy of an electron ejected from a metal by a photon is calculated using the equation K_max = hf - φ, where h is Planck's constant, f is the frequency of the photon, and φ is the work function of the metal. This equation indicates that the kinetic energy depends on both the photon's frequency and the metal's work function. The intensity of the light affects the number of electrons emitted, not their kinetic energy. Therefore, Option B is correct because it considers both the frequency of the photon and the metal's work function, while the other options do not account for all necessary factors.

Q143. A spring system executes simple harmonic motion. If a load is added to it then the time period of the spring-mass system will be:

• A. increased✓
• B. decreased
• C. the same
• D. halved

Explanation: The time period T of a spring-mass system is given by the formula T = 2π√(m/k), where m is the mass and k is the spring constant. As mass m increases, the time period T also increases because it is proportional to the square root of the mass. Therefore, when a load is added, the time period increases. This explains why the correct answer is 'increased'. The other options are incorrect because they do not align with the mathematical relationship between mass and time period in this system.

Q144. The diode that converts electrical energy into light energy is called:

• A. Solar cell
• B. Photodiode
• C. Vacuum diode
• D. Light emitting diode✓

Explanation: The correct answer is the Light Emitting Diode (LED). LEDs are specifically designed to emit light when an electric current passes through them. Unlike solar cells and photodiodes, which convert light energy into electrical energy, LEDs perform the reverse process. A vacuum diode is unrelated to light emission, as it primarily manages the direction of current flow in electronic circuits.

Q145. Which arrangement of the photons is in their decreasing energy?

• A. x rays > i.r. > u.v. > visible
• B. x rays > u.v. > visible > i.r.✓
• C. u.v. > x rays > visible > i.r.
• D. i.r. > visible > x rays > u.v.

Explanation: In the electromagnetic spectrum, the energy of photons is inversely proportional to their wavelength. Thus, shorter wavelengths correspond to higher energy. X-rays have the shortest wavelength and highest energy, followed by ultraviolet (u.v.) light, then visible light, and finally infrared (i.r.) light, which has the longest wavelength and lowest energy. Option B correctly reflects this order: x-rays > u.v. > visible > i.r.Other options are incorrect because they do not correctly arrange the types of radiation by decreasing energy according to their wavelength.

Q146. The colors in the soap bubble are due to:

• A. Interference✓
• B. Dispersion of light
• C. Scattering of light
• D. Refraction of light

Explanation: The colors in a soap bubble are due to interference of light. When light reflects off the outer and inner surfaces of the thin soap film, the waves overlap and interfere. This interference can be constructive or destructive, depending on the thickness of the film and the wavelength of light, creating the observed spectrum of colors. Other phenomena like dispersion, scattering, and refraction are unrelated to this scenario: dispersion involves splitting light into colors through a medium like a prism, scattering is light deflection by particles, and refraction is bending of light between different mediums.

Q147. An object in a satellite orbiting around the earth is weightless because:

• A. g = 0
• B. No force acts on it
• C. Its motion is free fall✓
• D. It is far away from the earth

Explanation: The correct answer is that an object in a satellite orbiting around the Earth is weightless because its motion is in free fall. In orbit, both the satellite and the objects inside it are in a constant state of free fall towards the Earth, but because they are moving forward fast enough, they keep missing it. This continuous free-fall condition results in the experience of weightlessness. While the force of gravity does act on the objects, the lack of a normal contact force, which we associate with weight, is what makes them feel weightless. This is different from the idea that gravity is zero or that no force acts on the object.

Q148. The expression for binding energy is:

• A. EB = fh
• B. EB = [(ZMP + N Mn) - ZMA] C2✓
• C. EB = ZMP C2 + N Mn ZMA C2
• D. EB = ZMP + N Mn - M C2

Explanation: The correct expression for nuclear binding energy is EB = [(ZMP + N Mn) - ZMA] C2. This equation accounts for the difference between the mass of the individual protons and neutrons and the actual mass of the nucleus, multiplied by the square of the speed of light, which reflects the mass-energy equivalence principle.Option A, EB = fh, pertains to energy quantization in quantum mechanics, not binding energy. Option C misplaces and incorrectly combines terms, leading to a false representation of binding energy. Option D also incorrectly assembles the terms and fails to account for necessary components of the formula.

Q149. The half-life of the given sample is 44 years. The sample will reduce to 50% of the original value after:

• A. 22 years
• B. 88 years
• C. 11 years
• D. 44 years✓

Explanation: The correct answer is 44 years because the half-life of a sample is defined as the time required for half of the sample to decay. Therefore, after 44 years, the sample will have reduced to 50% of its original value. Option A (22 years) is incorrect because it does not correspond to the half-life of the sample. Option B (88 years) is incorrect because it represents two half-lives, resulting in the sample reducing to 25% of its original value. Option C (11 years) is incorrect because it is not relevant to the concept of half-life.

Q150. The time rate of change of magnetic flux has the same dimension as that of:

• A. Current
• B. Resistance
• C. Magnetic induction
• D. Potential difference✓

Explanation: The time rate of change of magnetic flux has the same dimensions as potential difference, which is measured in volts (V). Therefore, option d is correct.

Q151. The transverse nature of light is verified with the phenomenon of:

• A. Interference
• B. Polarization✓
• C. Diffraction
• D. Dispersion

Explanation: The phenomenon of polarization is used to verify the transverse nature of light. Transverse waves are characterized by oscillations that are perpendicular to the direction of wave propagation. In polarization, light waves are filtered so that they vibrate in only one plane. This filtering process confirms that light waves oscillate in planes perpendicular to their direction of travel, hence proving their transverse nature.Other options like interference, diffraction, and dispersion involve light behaving as a wave but do not specifically demonstrate the transverse nature. Interference and diffraction deal with the superposition and bending of waves, while dispersion involves the separation of light into different colors. None of these directly show that light is transverse.

Q152. If a soap bubble is charged:

• A. Its size decreases
• B. Its size increases✓
• C. No change
• D. None of the above

Explanation: When a soap bubble is charged, either positively or negatively, the like charges spread over its surface due to electrostatic forces. These like charges repel each other, causing the bubble to expand and increase in size. Option B is correct because it accurately describes this phenomenon. Options A and C are incorrect as they suggest a decrease or no change in size, which contradicts the effects of electrostatic repulsion. Option D is incorrect because there is indeed a change.

Q153. An electric current of 1 A is passing through a cross section of the coil in 1 second. How many electrons are involved in providing a current of 1A? The charge on 1 electron is 1.602x10 – 19 C.

• A. 3.21 × 10^18
• B. 2.2 × 10^16
• C. 1.602 × 10^19
• D. 6.42 × 10^18✓

Explanation: To find the number of electrons involved in a current of 1 A, we use the formula:I = n × ewhere I is the current (1 A), n is the number of electrons, and e is the charge of an electron (1.602 × 10^-19 C).The number of electrons, n, can be calculated as:n = I / e = 1 / 1.602 × 10^-19This calculation gives approximately 6.25 × 10^18, usually approximated to 6.42 × 10^18 in standard options.Other options either miscalculate this division or misuse the given data.

Q154. The uncertainty recorded in the radius of a sphere is 1.6%. The uncertainty in the area of that sphere is:

• A. 4.8%
• B. 3.2%✓
• C. 1.6%
• D. 0.8%

Explanation: The uncertainty in a measurement involving exponentiation is multiplied by the exponent. For a sphere's area, which is proportional to the square of the radius, the formula for area is A = 4πr2. Therefore, the percentage uncertainty in the area is twice the percentage uncertainty in the radius. Given a 1.6% uncertainty in the radius, the area will have a 2 × 1.6% = 3.2% uncertainty.The incorrect options arise from misunderstanding how uncertainties propagate: 4.8% is calculated as if the exponent was 3, 1.6% is the original uncertainty in the radius, and 0.8% is an incorrect division.

Q155. An ideal transformer steps up or steps down:

• A. Energy
• B. AC voltage✓
• C. DC voltage
• D. Power

Explanation: An ideal transformer steps up or steps down AC voltage using the principle of electromagnetic induction. It consists of primary and secondary coils wound around a magnetic core. When AC voltage is applied to the primary coil, it creates a changing magnetic field, which induces an electromotive force (emf) in the secondary coil, altering the voltage. Transformers do not work with DC voltage because direct current does not produce a changing magnetic field. Additionally, while they can change voltage and current levels, the power transferred remains constant, assuming no energy losses, as per the conservation of energy principle.

Q156. Three equivalent resistors connected in parallel have equivalent resistance R/3. When they are connected in series then the equivalent resistance is:

• A. 3R✓
• B. R/3
• C. R
• D. 2R

Explanation: When three equivalent resistors are connected in parallel, the equivalent resistance is 3/R. When these same resistors are connected in series, their resistances add up, resulting in an equivalent resistance of 3R. Therefore, the correct option is 3R. Options B, C, and D are incorrect because they do not align with the calculations for equivalent resistance in parallel and series resistor connections.

Q157. Which one of the following is not a vector quantity?

• A. Electric field intensity
• B. Gravitational field intensity
• C. Magnetic induction
• D. Electromotive force✓

Explanation: The correct answer is electromotive force (EMF), which is a scalar quantity. Unlike vector quantities, EMF does not involve direction; it represents the energy provided per unit charge by a source. In contrast, electric field intensity, gravitational field intensity, and magnetic induction are vector quantities, all possessing both magnitude and direction.

Q158. Lenz‘s law is a particular form of the law of conservation of:

• A. Charge
• B. Current
• C. Energy✓
• D. Magnetic field

Explanation: Lenz’s law exemplifies the law of conservation of energy. It states that the induced electromotive force (emf) in a closed loop will generate a current whose magnetic field opposes the change in magnetic flux that produced it. This opposition ensures that energy is neither created nor destroyed but transformed from one form to another. For instance, when a magnet approaches a coil, the induced current opposes the motion, converting mechanical energy into electrical energy.Other options:Charge: While charge conservation is a fundamental principle, Lenz's law does not pertain to it.Current: Although related to currents, Lenz's law is not a specific form of current conservation.Magnetic field: Lenz's law involves the effects of changing magnetic fields but does not imply conservation of magnetic fields themselves.

Q159. The number of significant figures in the measurement x = 10.00300 are:

• A. 7✓
• B. 8
• C. 5
• D. 3

Explanation: The number of significant figures in a measurement includes all the certain digits plus the first uncertain digit. In the measurement x = 10.00300, all the digits are significant because:The digits '1' and '0' before the decimal point are significant.The digits '00300' after the decimal point are significant because they follow a non-zero digit.Thus, there are a total of 7 significant figures. Options B, C, and D are incorrect because they either overestimate or underestimate the count of significant figures.

Q160. Two equal, anti-parallel, and nonconcurrent forces are:

• A. Couple✓
• B. Couple arm
• C. Collinear forces
• D. Torque

Explanation: The correct answer is a Couple. A couple consists of two equal, anti-parallel, and nonconcurrent forces that act to produce a rotational effect, resulting in angular acceleration without causing the object to translate. This is distinct from collinear forces, which lie along the same line and do not produce rotation. 'Couple arm' refers to the distance between the lines of action of these forces, not the forces themselves. Torque, while related to rotational motion, refers to the measure of force that causes rotation about an axis and doesn't specifically describe the scenario of the two forces mentioned.

Q161. Minimum number of equal forces that keep the body in equilibrium are:

• A. Two✓
• B. Three
• C. Four
• D. Five

Explanation: Consider a particle having just one line of force acting on it. This force results in acceleration of the particle disturbing its equilibrium. The minimum number of equal forces required to keep a body in equilibrium is two. These forces must be equal in magnitude and opposite in direction to balance each other out and result in a net force of zero.

Q162. A ball of mass 5 kg is dropped from a height of 78.4 m. The time taken by the ball to hit the ground is:

• A. 2s
• B. 4s✓
• C. 8s
• D. 16s

Explanation: To solve this problem, we use the second equation of motion: S = ut + ½ gt2. Given data includes mass = 5 kg (not needed for time calculation), height (S) = 78.4 m, initial velocity (u) = 0 m/s, and acceleration due to gravity (g) = 9.8 m/s2. Substituting these values, the equation simplifies to 78.4 = 4.9t2. Solving for t2 gives t2 = 16, and taking the square root yields t = 4 seconds. Thus, the correct answer is 4 seconds. Options A (2s), C (8s), and D (16s) do not align with the reality of free-fall time from this height under Earth's gravity.

Q163. In electromagnetic waves, the electric and magnetic vectors are:

• A. Parallel
• B. Anti-parallel
• C. Perpendicular✓
• D. None of the above

Explanation: In electromagnetic waves, the electric and magnetic fields are oriented perpendicular to each other and to the direction of wave propagation. This orthogonal relationship is fundamental to the nature of electromagnetic waves, ensuring energy is transmitted efficiently through space. Option A is incorrect because electric and magnetic fields are never parallel in electromagnetic waves. Option B is incorrect as anti-parallel does not describe the orientation accurately. Option D is incorrect because there is a correct orientation mentioned in the options.

Q164. The negative gradient of electric potential is also called:

• A. Potential energy
• B. Electric field intensity✓
• C. Electric potential difference
• D. Electron-volt

Explanation: The correct answer is Electric field intensity. The electric field intensity is defined as the negative gradient of electric potential, shown by the equation E = -dV/dx. This means that the electric field points in the direction where the potential decreases most rapidly. The other options are incorrect because: Potential energy is related to position in a field, not potential gradients; Electric potential difference is the measure of work done per unit charge between two points and not a gradient; Electron-volt is a unit of energy, unrelated to potential gradients.

Q165. The centripetal force acting on a body rotating in a circle of radius ‗r‘ is ‗F‘. If the body moves in a circle of radius half of the initial value keeping other quantities constant, then the percentage change in the centripetal force is:

• A. 300%
• B. 100%✓
• C. 400%
• D. 200%

Explanation: To solve this problem, we start with the formula for centripetal force: F = (mv^2)/r.Initially, the force is F. When the radius is halved, the new radius is r/2. The new force becomes F' = (mv^2)/(r/2) = 2F.The percentage change in force is given by: [(F' - F) / F] × 100% = [(2F - F) / F] × 100% = 100%.Thus, the correct answer is 100%, which corresponds to Option B. Options A, C, and D represent incorrect calculations of the percentage change based on the new radius, leading to incorrect force changes.

Q166. Which one of the following properties of electromagnetic waves does not change in a vacuum?

• A. Speed✓
• B. Wavelength
• C. Frequency
• D. All of the above

Explanation: Electromagnetic waves travel at a constant speed of approximately 3 × 10^8 m/s in a vacuum. This speed is a fundamental property of the medium (the vacuum itself) and does not change with the frequency or wavelength of the wave. Wavelength and frequency are related through the equation c = fλ, where c is the speed of light, f is the frequency, and λ is the wavelength. In a vacuum, as the frequency changes, the wavelength adjusts to maintain the constant speed of light. Therefore, the speed of electromagnetic waves is the property that does not change in a vacuum.

Q167. MRI works on the principle of:

• A. Beats
• B. Interference
• C. Resonance✓
• D. Standing waves

Explanation: MRI, or Magnetic Resonance Imaging, operates on the principle of resonance. The strong magnetic field of the MRI machine aligns atomic nuclei in the body, and radio waves are used to disturb this alignment. When the radio waves are turned off, the nuclei return to their original state, emitting signals that are converted into detailed images. This process relies on the resonance of atomic nuclei in the magnetic field.The other options are incorrect: Beats are related to sound wave interference, interference involves wave superposition not central to MRI, and standing waves involve fixed wave patterns which are not part of MRI technology.

Q168. The waveform of sinusoidal voltage, its frequency and phase can be found by:

• A. CRO (Cathode Ray Oscilloscope)✓
• B. Diode
• C. Transistor
• D. Radio

Explanation: The correct answer is CRO (Cathode Ray Oscilloscope). A CRO is designed to visually display the waveform of electrical signals, allowing users to measure and analyze the signal's frequency, amplitude, and phase. It is a versatile tool used in laboratories and for troubleshooting electronic devices. On the other hand, a diode, transistor, and radio serve different purposes and are not capable of displaying or analyzing waveforms.

Q169. When a neutral body is rubbed and it becomes positively charged, it must have:

• A. Lost electrons✓
• B. Lost protons
• C. Gained protons
• D. Gained electrons

Explanation: When a neutral body becomes positively charged, it means it has lost electrons. Electrons are negatively charged, so removing some from a neutral atom or molecule leaves it with a net positive charge due to the unchanged number of protons. Option A is correct because losing electrons results in a positive charge. Option B is incorrect because losing protons would change the element entirely and not just the charge. Option C is incorrect because gaining protons is not feasible in this context and would also change the element. Option D is incorrect because gaining electrons would make the body negatively charged, not positively.

Q170. When a charged particle enters a uniform magnetic field, there is a change in:

• A. Kinetic energy
• B. Magnitude of velocity
• C. Direction of velocity✓
• D. All of these

Explanation: When a charged particle enters a uniform magnetic field, the magnetic force acts perpendicular to the velocity of the particle. This perpendicular force results in the particle's path bending, changing only the direction of the velocity while keeping its magnitude constant. Since the magnetic force does not do work on the particle, its kinetic energy remains unchanged. Therefore, the correct answer is that only the direction of velocity changes. Options A and B are incorrect because neither the kinetic energy nor the magnitude of velocity changes. Option D is incorrect because not all quantities change; only the direction of velocity is affected.

Q171. If two forces P and Q are such that |P + Q| = |P — Q|, then the angle between P and Q is:

• A. 0 degree
• B. 30 degree
• C. 90 degree✓
• D. 180 degree

Explanation: To solve this problem, use the properties of vector addition and subtraction. When |P + Q| = |P - Q|, the vectors P and Q must be perpendicular to each other. This occurs when the angle between them is 90 degrees.In terms of vector mathematics, this situation implies:P^2 + Q^2 + 2PQcos(x) = P^2 + Q^2 - 2PQcos(x)Solving this for x gives 4PQcos(x) = 0, which simplifies to cos(x) = 0. Therefore, x = 90 degrees.Options 0 degrees and 180 degrees would result in the magnitudes being clearly unequal due to vector alignment or opposition, respectively. Option 30 degrees would also not satisfy the condition of equal magnitudes.

Q172. Two blocks of masses 1.0 kg and 3.0 kg placed in contact are acted upon by a force of 40 N. The acceleration of 1.0 kg mass will be:

• A. 40 ms^-2
• B. 10 ms^-2✓
• C. 30 ms^-2
• D. 50 ms^-2

Explanation: In this scenario, the two blocks are in contact and can be treated as a single system with a total mass of 1.0 kg + 3.0 kg = 4.0 kg. The force applied is 40 N. According to Newton's second law, F = ma, where F is the force applied, m is the total mass, and a is the acceleration.Here, the acceleration a can be calculated as:a = F / (m1 + m2) = 40 N / 4.0 kg = 10 ms^-2.Thus, the acceleration of the 1.0 kg mass is 10 ms^-2, as both blocks will accelerate together as a single system.Option A (40 ms^-2) is incorrect as it does not account for the total mass. Option C (30 ms^-2) is a miscalculation. Option D (50 ms^-2) exceeds the possible acceleration given the force and mass.

Q173. A body in equilibrium must not have:

• A. Kinetic energy
• B. Velocity
• C. Momentum
• D. Acceleration✓

Explanation: For a body to be in equilibrium, it must have zero net acceleration, which is the result of all external forces canceling each other out. This ensures that the body does not change its state of motion. While kinetic energy, velocity, and momentum can exist, they must remain constant, indicating no net external force is present. Acceleration, however, signifies a change in the state of motion due to a net force, which contradicts the condition of equilibrium.

Q174. Sound waves cannot be:

• A. Polarized✓
• B. Reflected
• C. Refracted
• D. Diffracted

Explanation: Sound waves are longitudinal waves, meaning their oscillations occur in the same direction as their propagation. This characteristic makes it impossible for sound waves to be polarized, as polarization requires the wave oscillations to be perpendicular to the direction of propagation, as seen in transverse waves like light. On the other hand, sound waves can be reflected, refracted, and diffracted due to their ability to interact with different surfaces and mediums in various ways.

Q175. The spring constant of a spring is k. If the spring is cut into two halves then the spring constant of one of the halves is:

• A. k + 2
• B. k/2
• C. 2k✓
• D. k

Explanation: According to Hooke's Law, the force exerted by a spring is given by F = -kx, where k is the spring constant and x is the displacement. The spring constant is a measure of the spring's stiffness. When a spring is cut into two equal halves, each half becomes stiffer because the same force is now applied over a shorter distance. Therefore, the spring constant of each half becomes twice the original, or 2k. The other options are incorrect because they do not accurately reflect this relationship. Option A incorrectly adds a constant, Option B incorrectly assumes the spring constant is halved, and Option D assumes the spring constant remains unchanged.

Q176. A force of 6 N acts horizontally on a stationary mass of 2 kg for 4 s. The kinetic energy in Joule is:

• A. 12
• B. 144✓
• C. 72
• D. 48

Explanation: To determine the kinetic energy of the mass after 4 seconds, apply Newton's second law. Given that the force (F) is 6 N and the mass (m) is 2 kg, we first find the acceleration (a) using F = ma, resulting in a = 3 m/s².Initially, the object is stationary, so the initial velocity (u) is 0. The final velocity (v) can be calculated using v = u + at, where t is 4 seconds, giving v = 12 m/s.Now, calculate the kinetic energy (KE) using the formula KE = 1/2 mv². Substituting the values, KE = 1/2 × 2 × (12)² = 144 J.The other options are incorrect due to either a miscalculation of velocity or an incorrect application of the kinetic energy formula.

Q177. A person travels a distance x = 20t+2At2, where A is a constant. The acceleration of the person is:

• A. A/4 ms^–2
• B. 4/A ms^–2
• C. 4 ms^-2
• D. 4A ms^–2✓

Explanation: The given equation for distance is x = 20t + 2At^2. To find acceleration, we need to differentiate this equation with respect to time.First, differentiate to find velocity (v):v = dx/dt = d(20t + 2At^2)/dt = 20 + 4At.Then, differentiate the velocity to find acceleration (a):a = dv/dt = d(20 + 4At)/dt = 4A.Therefore, the acceleration of the person is 4A.The other options are incorrect as they either misinterpret the role of the constant A or incorrectly calculate the differentiation process.

Q178. In the nuclear reaction 11 Na24 12Mg24 + X, the particle X is;

• A. Electron✓
• B. Positron
• C. Proton
• D. Neutron

Explanation: In the nuclear reaction 11Na24 → 12Mg24 + X, the atomic number increases by one, indicating a beta-minus decay. In this process, a neutron in the sodium nucleus is converted into a proton, resulting in the emission of an electron (beta particle) and an antineutrino. Thus, the particle X is an electron.The other options are incorrect because:A positron emission would decrease the atomic number, which contradicts the observed increase.A proton emission would change the atomic number, but not in a way that matches the given reaction.A neutron emission would affect the mass number but not lead to the increase in atomic number observed here.

Q179. The angular displacement made by the minute hand of a watch after 5.0 minutes is:

• A. 30 degrees✓
• B. 120 degrees
• C. 180 degrees
• D. 360 degrees

Explanation: In a full hour, the minute hand of a watch completes a 360-degree rotation, which is equivalent to 2π radians. Since there are 60 minutes in an hour, the minute hand moves at a rate of 6 degrees per minute (360 degrees / 60 minutes = 6 degrees per minute). Therefore, in 5 minutes, the minute hand moves 5 * 6 = 30 degrees.The correct answer is 30 degrees because this corresponds to the angular displacement of the minute hand over 5 minutes. The other options represent angular displacements for different time periods: 120 degrees for 20 minutes, 180 degrees for 30 minutes, and 360 degrees for a full hour.

Q180. The intensity of a wave is:

• A. Directly proportional to the amplitude
• B. Directly proportional to (amplitude)2✓
• C. Inversely proportional to amplitude
• D. Inversely proportional to (amplitude)2

Explanation: The intensity of a wave is directly proportional to the square of its amplitude (I∝A2). This means if the amplitude of a wave doubles, the intensity increases by a factor of four. Option B is correct because it accurately reflects this relationship. Option A is incorrect because it implies a linear relationship, which is not the case. Options C and D are incorrect because they suggest that intensity is inversely related to amplitude, which contradicts the fundamental principle of wave physics.

Q181. Conversion of alternating current into direct current is called:

• A. Rectification✓
• B. Amplification
• C. Oscillation
• D. Regeneration

Explanation: Rectification is the correct answer because it specifically refers to the conversion of alternating current (AC) into direct current (DC). This process is essential in many electronic devices that require a stable DC supply from an AC source. Amplification is incorrect because it pertains to increasing the strength of a signal, not converting it. Oscillation is incorrect as it describes a repetitive back-and-forth motion, not a conversion process. Regeneration is incorrect because it is not related to electrical circuitry or processes.

Q182. Which of the following pairs have the same units and dimensions?

• A. Resistance and resistivity
• B. Conductivity and resistivity
• C. Electromotive force and potential difference✓
• D. Resistivity and temperature coefficient of resistivity

Explanation: The correct answer is Option C: Electromotive force and potential difference. Both are measured in volts (V) and have the same dimensions. EMF represents the energy provided per coulomb of charge, while potential difference measures the energy used per coulomb as it moves between two points.Option A is incorrect because resistance and resistivity have different units. Resistance is in ohms (Ω), whereas resistivity is in ohm-meters (Ω⋅m).Option B is incorrect because conductivity and resistivity are inversely related but have different units; conductivity is in siemens per meter (S/m) and resistivity is in ohm-meters (Ω⋅m).Option D is incorrect because resistivity and the temperature coefficient of resistivity have different units; resistivity is in ohm-meters (Ω⋅m) and the temperature coefficient of resistivity is in per degree Celsius (1/°C).

Q183. The activity of the radioactive material can be expressed in the unit of:

• A. curie
• B. Becquerel
• C. Tesla
• D. both a and b✓

Explanation: The activity of a radioactive material, which represents the rate of decay of radioactive nuclei, can be expressed in units of both curie (Ci) and becquerel (Bq).

Q184. The work function of a metal is 6.63 eV. The threshold frequency of the metal is:

• A. 1.6 × 10^15 Hz✓
• B. 1.6 × 10^12 Hz
• C. 6.63 × 10^-34 Hz
• D. 1.6 × 10^-19 Hz

Explanation: The work function (W) is the minimum energy required to remove an electron from the surface of a metal. It is related to the threshold frequency (V) by the formula V = W/h, where h is Planck's constant (6.626 × 10^-34 J·s). To find the threshold frequency in Hertz, convert the work function from electronvolts to joules (1 eV = 1.602 × 10^-19 J), and then divide by Planck's constant:V = (6.63 eV × 1.602 × 10^-19 J/eV) / (6.626 × 10^-34 J·s) = 1.6 × 10^15 Hz.Option A is correct because it reflects this calculation. Options B, C, and D are incorrect because they either misrepresent the relationship between work function and threshold frequency or use incorrect values.

Q185. The birds sitting on an overhead transmission line suffer no harmful effects because:

• A. Their bodies have high resistance
• B. Their feet are good insulators
• C. There is a negligible potential difference between their feet✓
• D. Wires are insulated

Explanation: Birds perched on an overhead transmission line are not harmed because both of their feet are at the same electrical potential, eliminating the potential difference required for current to flow through their bodies. Hence, no current passes through them. Option A is incorrect because the resistance of the bird's body is not the determining factor. Option B is incorrect because the bird's feet are not insulators, but rather, they maintain the same potential on a single wire. Option D is incorrect as transmission lines are not typically insulated, but rather, the lack of potential difference keeps the birds safe.

Q186. Which of the following are Ohmic materials?

• A. Semiconductors
• B. Tungsten filament
• C. Thermistor
• D. Metals✓

Explanation: Ohmic materials are those that follow Ohm's Law, where the resistance (R) is constant regardless of the applied voltage (V) or current (I). Metals, such as copper and aluminum, are typical examples of ohmic materials because they maintain a consistent resistance under typical conditions. In contrast, semiconductors, tungsten filaments, and thermistors do not maintain a constant resistance. Semiconductors have variable resistance due to their dependence on factors like doping, temperature, and voltage. Tungsten filaments change resistance with temperature increases. Thermistors are designed to have a resistance that varies with temperature. Hence, they are non-ohmic materials.

Q187. Optical fibers guides:

• A. Current
• B. Light✓
• C. Sound
• D. Voltage

Explanation: Optical fibers are designed to guide light, which is used for transmitting data over long distances with minimal loss. The core of an optical fiber is made of glass or plastic, allowing light to bounce along its length in a process called total internal reflection. This makes them ideal for high-speed data transmission. Options such as current, sound, and voltage are incorrect because optical fibers do not guide electrical currents, sound waves, or electrical voltages; they are specifically engineered for light transmission.

Q188. A hunter aiming a bird in tree should aim:

• A. A little above the bird✓
• B. A little below
• C. Exactly at the bird
• D. Very high

Explanation: When a hunter aims at a bird in a tree, they should aim a little above the bird. This is because of the effect of gravity on the bullet or projectile. By aiming slightly higher, the bullet will follow a curved path due to gravity and have a better chance of hitting the bird.

Q189. The velocity of the projectile at its maximum height is:

• A. Zero
• B. Minimum✓
• C. Maximum
• D. In between maximum and minimum

Explanation: In projectile motion, the velocity of a projectile can be broken down into horizontal and vertical components. At the maximum height, the vertical component of the velocity becomes zero, while the horizontal component remains unchanged. Therefore, the overall velocity is at its minimum at this point, which is why option B is correct. Option A is incorrect because the overall velocity isn't zero; only the vertical component is. Option C is incorrect because the maximum velocity occurs at the point of launch or impact, not at the maximum height. Option D is incorrect because the velocity is at its minimum when the vertical component is zero.

Q190. Hook‘s law correlates the:

• A. Force and displacement
• B. Force and extension
• C. Force and compression
• D. Stress and strain✓

Explanation: Hooke's Law is a principle of physics that states the strain in a solid is proportional to the applied stress within the elastic limit of that material. Mathematically, it can be expressed as Stress/Strain = Constant. This means that the material will return to its original shape after the stress is removed, as long as the elastic limit is not surpassed. The other options mention relationships that are not the fundamental focus of Hooke's Law. While force can influence displacement, extension, and compression, Hooke's Law specifically addresses the proportional relationship between stress and strain.

Q191. Two forces of magnitude 20 N and 10 N act at a point then which one of the following cannot be their possible sum?

• A. 30 N
• B. 10 N
• C. 35 N✓
• D. 15 N

Explanation: The resultant force of two vectors can range from the absolute difference to the absolute sum of their magnitudes, depending on their relative direction. For forces of 20 N and 10 N, the possible resultant can range from 10 N (when acting in opposite directions) to 30 N (when acting in the same direction). Therefore, 35 N exceeds this range and cannot be a resultant of these two forces. The other options (10 N, 15 N, and 30 N) all fall within the possible range for the resultant force.

Q192. When a force is applied to a body, several effects are possible. Which one of the following effects could not occur?

• A. The body speeds up
• B. The body rotates
• C. The body changes direction
• D. Mass of body decreases✓

Explanation: The correct answer is that the mass of the body decreases. The mass of a body is an intrinsic property that remains unchanged when a force is applied. Forces can change the speed, cause rotation, or alter the direction of a body's motion, but they do not change mass. Options A, B, and C describe possible effects of force application, such as acceleration, rotation, or direction change, all of which are consistent with the laws of physics.

Q193. The shortest wavelength of radiation in Paschen series is:

• A. RH/9
• B. 9/RH✓
• C. 9 RH
• D. 9 + RH

Explanation: The Paschen series corresponds to electron transitions to the n = 3 level in a hydrogen atom. The formula for the shortest wavelength (longest energy transition) in any series is given by λ = 1/RH (1/n1² - 1/∞²), where n1 is the lower energy level and RH is the Rydberg constant. For the Paschen series, n1 = 3, so the formula becomes λ = 1/RH (1/3² - 0) = 9/RH. Therefore, option B is correct. Options A, C, and D are incorrect because they misapply the formula, using multiplication or addition instead of the correct reciprocal form.

Q194. The part of the electromagnetic spectrum in which Lyman series lies is:

• A. Visible region
• B. Infrared region
• C. Ultraviolet region✓
• D. X-rays

Explanation: The Lyman series is a set of spectral lines in the hydrogen atom that occur when an electron transitions from a higher energy level (n ≥ 2) down to the lowest energy level (n = 1). These transitions release photons in the ultraviolet region of the electromagnetic spectrum, which is why the Lyman series lies in the ultraviolet region. The Balmer series, on the other hand, is visible, while the Paschen, Brackett, and Pfund series lie in the infrared region. No hydrogen spectral series corresponds to the X-ray region, which requires much higher energy transitions.

Q195. The first law of thermodynamics is a statement which implies that:

• A. No heat enters or leaves the system
• B. The temperature remains constant
• C. All work is mechanical
• D. Energy is conserved✓

Explanation: The first law of thermodynamics states that energy can neither be created nor destroyed, it is converted from one form to another, therefore the answer will be D

Q196. The sinusoidal AC in a circuit is I = 50 sin (20 t). The peak value of the current is:

• A. 100 A
• B. 25 A
• C. 50 A✓
• D. 20 A

Explanation: The sinusoidal AC current given by the equation I = 50 sin(20t) has a peak value that is determined by the amplitude of the sine function. In this context, the peak value is the maximum value the current can reach, which is represented by the coefficient of the sine function, 50 A. Therefore, option C is correct.Option A is incorrect because 100 A is not the amplitude of the sine function. Option B is incorrect because 25 A is half of the amplitude, not the full peak value. Option D is incorrect because 20 A is the angular frequency's coefficient, not the peak current.

Q197. Current in the semiconductors is caused by the movement of:

• A. Protons
• B. Electrons only
• C. Holes only
• D. Both electrons and holes✓

Explanation: In semiconductors, current is generated by the movement of charge carriers: electrons and holes. Electrons, which are negatively charged, move through the conduction band, while holes, which are effectively positive charge carriers due to the absence of electrons, move through the valence band. Both types of carriers are essential for the flow of current. Protons do not contribute to current flow as they are locked within the atomic nucleus and do not move. Thus, the correct answer is that current in semiconductors is caused by the movement of both electrons and holes.

Q198. Darwin observed and collected thousands of specimens of diverse:

• A. Fauna of South America
• B. Flora of South America
• C. Fauna and flora of South America✓
• D. Fauna and flora of North America

Explanation: During his journey on the HMS Beagle, Charles Darwin meticulously observed and gathered a diverse collection of specimens, including both fauna and flora, from South America. His comprehensive study of these specimens, which were distinct from those in Europe, played a crucial role in the development of his theories on natural selection and evolution. Option C is correct, as it accurately reflects the breadth of his research. Options A and B are incorrect, as they focus solely on one type of specimen (either fauna or flora), while Option D is incorrect due to the erroneous geographical reference to North America.

Q199. Archaeopteryx possessed both _ and _ characters:

• A. Reptilian, Amphibian
• B. Reptilian, Avian✓
• C. Fish, Avian
• D. Mammalian, Avian

Explanation: Archaeopteryx is a critical fossil that provides evidence for evolution by illustrating the link between reptiles and birds. Dating back to the Late Jurassic period, around 150 million years ago, it exhibits a unique mix of features: reptilian traits such as a long bony tail, teeth, and claws, alongside avian traits like feathers and wings. This makes it a classic example of a transitional fossil. The incorrect options fail to represent this specific combination of reptilian and avian features accurately.

Q200. The idea of inheritance of acquired characteristics was given by:

• A. Lamarck✓
• B. Darwin
• C. Aristotle
• D. Lyell

Explanation: The correct answer is Lamarck. He introduced the concept that traits acquired in an organism's lifetime could be inherited by its descendants, forming a crucial part of his evolutionary theory. In contrast, Darwin's theory of evolution is based on natural selection, focusing on variation and survival of the fittest, without involving the inheritance of acquired traits. Aristotle did not believe in evolution through acquired characteristics, maintaining that species were immutable. Lyell's contributions lie in geology, specifically in understanding Earth's processes, without addressing biological evolution.