Sindh Mcat Nts 2019 — Solved Past Paper with Answers

Q1. Choose the word most similar in meaning to the capitalized one.DEMONSTRATE:

• A. Establish
• B. Invent
• C. Produce
• D. Show✓

Explanation: Show refers to displaying something. Option D is the best choice here which is a synonym of demonstrate.

Q2. Choose the word most similar in meaning to the capitalized one.FLEE

• A. Escape✓
• B. Face
• C. Fear
• D. Flow

Explanation: The correct answer is Escape because both 'flee' and 'escape' involve the action of running away or getting away from a threat or danger. 'Flee' specifically implies a hurried or urgent departure to avoid danger.

Q3. Choose the word most similar in meaning to the capitalized one.UNAMBIGUOUS:

• A. Exact
• B. Clear✓
• C. Interesting
• D. Sufficient

Explanation: The word 'unambiguous' means clear, with no room for doubt or confusion. The correct answer is 'Clear' because it directly reflects this meaning of being easily understood or interpreted.

Q4. choose the word most similar in meaning to the capitalized one.LEGEND:

• A. History
• B. Outburst
• C. Place
• D. Story✓

Explanation: Legend refers to a traditional story and a tale about something. Hence, Option D is correct.

Q5. Read the passage and answer the following question:The thought that freedom means freedom only from foreign domination, is an outworn idea. It is not merely governments that should be free but the people themselves who should be free; and no freedom has any real value for the common man or woman unless it means freedom from want, freedom from disease, freedom from ignorance. This is the main task that confronts us if we are to take our rightful place in the modern world. We cannot hold the clock back, and there it is we who must go forward at a double pace bending all our resources and all our energies to this great purpose.The "great purpose" mentioned by the writer at the end of the passage refers to:

• A. Freedom from foreign domination
• B. People themselves should be free
• C. The real value of freedom✓
• D. Taking our rightful place in the modern world

Explanation: The correct answer is C: The real value of freedom. The passage argues that true freedom involves more than just political autonomy; it includes freedom from want, disease, and ignorance. This comprehensive understanding of freedom is described as the 'great purpose' toward which efforts should be directed.

Q6. Read the passage and answer the following question:The thought that freedom means freedom only from foreign domination, is an outworn idea. It is not merely governments that should be free but the people themselves who should be free; and no freedom has any real value for the common man or woman unless it means freedom from want, freedom from disease, freedom from ignorance. This is the main task that confronts us if we are to take our rightful place in the modern world. We cannot hold the clock back, and there it is we who must go forward at a double pace bending all our resources and all our energies to this great purpose.The "great purpose" mentioned by the writer at the end of the passage refers to:

• A. Freedom from foreign domination
• B. People themselves should be free
• C. The real value of freedom✓
• D. Taking our rightful place in the modern world

Explanation: The correct answer is C: The real value of freedom. The passage argues that true freedom involves more than just political autonomy; it includes freedom from want, disease, and ignorance. This comprehensive understanding of freedom is described as the 'great purpose' toward which efforts should be directed.

Q7. Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters.BRILLIANT

• A. Adequate
• B. Dull✓
• C. Troubled
• D. Unprejudiced

Explanation: Brilliant refers to something being extraordinary and very bright. Dull is the best antonym for bright.

Q8. Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters.ENFEEBLED:

• A. Distanced
• B. Dominant
• C. Mistaken
• D. Powerful✓

Explanation: Enfeebled means someone lacking physical strength and being weak. Powerful is the direct opposite of this word.

Q9. Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters.UNLIKELY:

• A. Familiar
• B. Possible✓
• C. Powerful
• D. Take for granted

Explanation: The word 'UNLIKELY' indicates that something has a low chance of happening. The correct opposite is 'Possible', which means there is a good chance something will occur.

Q10. Read the passage and answer the following question:Anglo-Saxon is now, of course, a dead language, but a good deal of its vocabulary has survived, in one form or another to the present day. Most of the very common words in modern English are Anglo-Saxon in origin; nouns like father, mother, food, drink, bed, hunger; most of the prepositions and conjunctions; and nearly all the strong verbs. When it was mixed with Norman French, there were three main results: the grammar was simplified, the pronounciation and spellings became much more complicated and the vocabulary was enormously extended. French is a Latin language, so the major part of our vocabulary is now Latin in origin.A “dead language” is:

• A. A dialect of language
• B. Latin language
• C. Mixed with other languages
• D. No more spoken✓

Explanation: A 'dead language' refers to a language that is no longer spoken in everyday life. This is distinct from a dialect, which is a variation of a language still in use. While Latin is a 'dead language', not all dead languages are Latin. Mixing with other languages doesn't define a language as dead; it simply describes a process of linguistic evolution. Therefore, the correct option is the one that states a dead language is 'no more spoken'.

Q11. Read the passage and answer the following question:Anglio - Saxon is now, of course, a dead language, but a good deal of its vocabulary has survived, in one form or another to the present day. Most of the very common words in modern English are Anglo - Saxon in origin; nouns like father, mother, food, drink, bed, hunger; most of the prepositions and conjunctions; and nearly all the strong verbs. When it was mixed with Norman French, there were three main results: the grammar was simplified, the pronunciation and spellings became much more complicated and the vocabulary was enormously extended. French is a Latin language, so the major part of our vocabulary is now Latin in origin.The vocabulary was “enormously extended” means vocabulary has:

• A. Increased✓
• B. Reduced
• C. Simplified
• D. Survived

Explanation: The correct answer is 'Increased'. The passage states that the English vocabulary was 'enormously extended' due to the blending of Anglo-Saxon with Norman French. This means that the vocabulary increased significantly as new words were incorporated into the language.

Q12. Identify the word or phrase that needs to be changed for the sentence to be correct.When I go into a bank, I get frighten.

• A. When
• B. I
• C. Get
• D. Frighten✓

Explanation: The sentence contains a grammar error where the verb 'frighten' is incorrectly used in place of the adjective 'frightened'. The sentence should describe the state of being scared, so 'frightened' is the correct choice. The word 'When' correctly introduces the clause, and 'I' is the correct subject pronoun. 'Get' is appropriate in its position, but it should be coupled with 'frightened' rather than 'frighten'.

Q13. Identify the word or phrase that needs to be changed for the sentence to be correct.The fact of the matter is never I’d been out to the theatre that night, had supper afterwards, and came in late.

• A. Never✓
• B. That
• C. Late
• D. Afterwards

Explanation: The key to solving these questions is reading them in your head and deciphering which part sounds odd. If you remove the word never, the sentences make much more sense.

Q14. identify the word or phrase that needs to be changed for the sentence to be correct.In Maxwell’s days, no instruments had been made which could register the greatly enormously long waves of electricity.

• A. No
• B. Could
• C. Greatly✓
• D. No error

Explanation: The key to solving these questions is reading them in your head and deciphering which part sounds odd. It could have been “greatly enormous” long waves. But if enormous also ends with a -ly then it should be great instead.

Q15. Identify the word or phrase that needs to be changed for the sentence to be correct.This long experience of European domination has naturally produced a mood of quite resistance.

• A. This
• B. Long
• C. European
• D. Quite✓

Explanation: Over here quite is wrongly used as the other homophone (quiet) was the intended word. Meaning the resistance is very quietly developing in secret. Quite is an adverb used to describe when something is a little or a lot but not completely. Quiet is an adjective used to describe something or someone that makes very little noise.

Q16. Complete the sentences by choosing the most appropriate option, from the given lettered choices (A to D) below each:The house _ before we moved in.

• A. Paint
• B. Painted
• C. Has painted
• D. Was painted✓

Explanation: The key to solving these questions is reading them in your head filling in each option and then deciphering which option fits in well. The sentence here is clearly in the past tense hence Option D is the correct option as it indicates the house was painted.

Q17. Complete the sentences by choosing the most appropriate option, from the given lettered choices below each:Her hair was hanging _ her back.

• A. Beyond
• B. By
• C. Down✓
• D. From

Explanation: “Beyond” is not correct because it means past or on the other side of something. If we say her hair was hanging beyond her back, it suggests the hair extended past the back to some farther point, which is not the usual meaning. We simply want to say the hair was lying down her back, not going past it. Therefore, “down her back” is the correct expression.

Q18. Complete the sentences by choosing the most appropriate option, from the given lettered choices below. We must _ back by six o’clock.

• A. Be✓
• B. Can
• C. Has
• D. Have

Explanation: The sentence requires a word that fits grammatically and logically in the expression 'must _ back by six o’clock.' The correct choice is 'be' because 'must be back' is a standard expression indicating an obligation or necessity to return by a specified time. The other options ('can,' 'has,' 'have') do not form correct or meaningful expressions in this context.

Q19. Complete the sentences by choosing the most appropriate option, from the given lettered choices (A to D) below each:Birds usually _ eggs in their nests.

• A. Laid
• B. Lain
• C. Lay✓
• D. Lie

Explanation: The correct answer is 'lay'. The sentence describes a habitual action, indicated by the word 'usually', which requires the present tense form of the verb. 'Lay' is the correct verb form for describing the action of birds placing eggs in their nests. 'Laid' is past tense, 'lain' is a past participle of 'lie' meaning to recline, and 'lie' can mean either recline or not tell the truth, neither of which fit the context of the sentence.

Q20. Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters.INVADERS:

• A. Defenders✓
• B. Historians
• C. Inhabitants
• D. Nomads

Explanation: Defenders → those who protect a place from attack. So, it is opposite for "invaders".

Q21. In sexual reproduction, sex cells contain _ chromosomes when compared to other cells of the body:

• A. Same
• B. Half✓
• C. Double
• D. All of the above

Explanation: In sexual reproduction, sex cells (gametes) are formed through a process called meiosis, which reduces the chromosome number by half. This is crucial because it ensures that when two gametes fuse during fertilization, the resulting offspring has the correct diploid number of chromosomes. Option B is correct because sex cells contain half the number of chromosomes compared to somatic cells. Option A is incorrect because gametes do not have the same number of chromosomes as body cells. Option C is incorrect because gametes do not contain double the chromosomes. Option D is incorrect as only one option accurately describes the chromosome number in sex cells.

Q22. During cell division, the spindle fibres get attached to condensing chromosome at a highly differentiated region. This region is called as:

• A. Chromosome
• B. Chromocentre
• C. Centriole
• D. Kinetochore✓

Explanation: The correct answer is 'Kinetochore'. During mitosis, spindle fibers attach to the kinetochore, a protein complex on the chromosome's centromere. This attachment is essential for chromosome alignment and segregation. A kinetochore is a flared oblique-shaped protein structure associated with duplicated chromatids in eukaryotic cells where the spindle fibers, which can be thought of as the ropes pulling chromosomes apart, attach during cell division to pull sister chromatids apart.Other options: 'Chromosome' refers to the entire structure of DNA and protein, not the specific attachment site. 'Chromocentre' is not involved in mitosis. 'Centriole' helps organize spindle fibers but does not serve as the attachment site on chromosomes.

Q23. Congenital under-secretion of thyroxine causes:

• A. Grave’s disease
• B. Myxedema
• C. Addison’s disease
• D. Cretinism✓

Explanation: Cretinism (congenital hypothyroidism) causes stunted growth and mental retardation due to low thyroxine during fetal life.

Q24. In higher animals' bodies, tissue fluid is isotonic contrary to plants because in plant cells:

• A. Cell membrane creates resistance in water uptake
• B. Plastids create resistance in water uptake
• C. Chlorophyll creates resistance in water uptake
• D. Cell wall creates resistance in water uptake✓

Explanation: In plant cells, the presence of a rigid cell wall creates pressure potential, which contributes to the overall osmotic balance by exerting resistance against excessive water uptake. This prevents the cells from becoming plasmolyzed or turgid beyond a certain point. In contrast, animal cells lack such a structure, relying instead on isotonic conditions to maintain equilibrium. As a result, tissue fluid in higher animals is isotonic to prevent osmotic imbalance. The incorrect options confuse the role of different organelles and components; the cell membrane, plastids, and chlorophyll do not contribute to water uptake resistance as the cell wall does.

Q25. Which one is NOT an involuntary function:

• A. Breathing
• B. Pumping of blood
• C. Skeletal muscle movement✓
• D. Blinking of eyes

Explanation: Skeletal muscle movement is the correct answer because it is a voluntary function, meaning it is under conscious control. The other options—breathing, pumping of blood, and blinking of eyes—are primarily involuntary functions controlled by the autonomic nervous system. While you can consciously control breathing and blinking to some extent, they generally occur automatically, unlike skeletal muscle movement, which requires conscious intent to perform.

Q26. In gametogenesis, which resultant product is non-functional?

• A. A. Spermatogonia
• B. B. Oogonia
• C. C. Polar body✓
• D. D. Ovum

Explanation: The correct answer is Option C: Polar body. During oogenesis, a mature ovum is formed alongside smaller cells known as polar bodies. Polar bodies are haploid cells that lack the cytoplasmic components necessary for fertilization, rendering them non-functional in terms of reproductive capability. On the other hand, spermatogonia (Option A) and oogonia (Option B) are precursor cells that eventually lead to the production of functional gametes. The ovum (Option D) is the egg cell capable of being fertilized, making it the functional product of oogenesis.

Q27. The passageways of the respiratory system have mucous secreting cells called:

• A. Tracheal cells
• B. Goblet cells✓
• C. Surfactant cells
• D. Pleural cells

Explanation: Goblet cells are the specialized cells within the respiratory tract responsible for secreting mucus, which helps trap dust and microbes.

Q28. The virus can only survive and reproduce inside a:

• A. Animal Cell
• B. Bacterial cell
• C. Living cell✓
• D. Non-living cell

Explanation: Viruses need a living cell to replicate because they cannot carry out life processes on their own. They utilize the host cell's machinery for survival and reproduction. While viruses can infect animal and bacterial cells, the essential factor is that the cell must be living. Non-living cells do not exist, rendering that option invalid.

Q29. In addition to smaller hind limb muscle mass, the mutant "mini Muscle” gene exhibits lower heart rates during physical activity, and larger kidneys and livers in mice. This is a very good example of _.

• A. Epistasis
• B. Multiple alleles
• C. Codominance
• D. Pleiotropy✓

Explanation: Pleiotropy is a genetic situation where one gene impacts multiple, seemingly unrelated phenotypic traits. The example of the 'mini Muscle' gene impacting muscle mass, heart rate, and organ sizes in mice illustrates this principle. The other options are incorrect because they describe different genetic phenomena: Epistasis involves gene interactions, Multiple alleles involve more than two gene variants, and Codominance involves equal expression of two alleles rather than a single gene affecting multiple traits.

Q30. _ is the stage of mitosis characterized by the physical separation of _ chromatids.

• A. Interphase, daughter
• B. Telophase, genetic
• C. Metaphase, sister
• D. Anaphase, sister✓

Explanation: Anaphase is the correct answer because it is the stage in mitosis where sister chromatids are physically separated and move towards opposite poles of the cell. This separation is facilitated by the shortening of spindle fibers. In contrast, during Metaphase, chromosomes only align at the cell's equator without separation. Telophase involves the reformation of the nuclear envelope around the separated chromatids, and Interphase is the preparatory phase for cell division, not part of mitosis itself.

Q31. A man who has type AB blood cannot be the father of a child with type _ blood, because he would pass on either the _ or the B allele to all of his offspring.

• A. A, O
• B. O, A✓
• C. B, O
• D. B, A

Explanation: A man with type AB blood possesses both A and B alleles. When he fathers a child, he will pass on either the A or B allele to his offspring. For a child to have type O blood, they must inherit an O allele from both parents. Since the man with type AB blood cannot provide an O allele, it is impossible for him to father a child with type O blood. This is why option B is correct. Other options such as type A and type B are possible if the mother contributes an O allele, as A and B are dominant over O.

Q32. Identify purine and pyrimidines from the following figures

• A. A and B are purines, and C, D, and E are pyrimidines.
• B. D and B are purines, and C, A, and E are pyrimidines.
• C. A and E are purines, and C, D, and B are pyrimidines.
• D. A and C are purines, and B, D, and E are pyrimidines.✓

Explanation: The correct answer is that A and C are purines, and B, D, and E are pyrimidines. Purines, such as adenine and guanine, have a two-ring structure, while pyrimidines, like thymine, cytosine, and uracil, have a single-ring structure. This structural difference is crucial for the formation of DNA and RNA, as it affects how these molecules pair and interact. The incorrect options either misidentify the base structures or do not adhere to the characteristic number of rings for purines and pyrimidines.

Q33. A cross between a black cat and a tan cat produces a tabby pattern (black and tan fur together). What percent of kittens would have tan fur if a tabby cat is crossed with a black cat?

• A. 100%
• B. 50%
• C. 25%
• D. 0%✓

Explanation: The correct answer is 0%. The black cat is homozygous for the black fur gene (BB) and does not carry an allele for tan fur. The tabby cat, being a hybrid, has one black fur allele (B) and one tan fur allele (T). When crossed with a black cat, the potential offspring genotypes are BB (black) and BT (tabby), with no possibility of a TT (tan) genotype. Thus, none of the kittens will have tan fur. The other options are incorrect because they suggest the presence of a tan allele in the black parent, which is not possible given the genetic information provided.

Q34. Which factor decides what type of variation should be flourished and passed on to the next generations?

• A. Species
• B. Population
• C. Survival
• D. Environment✓

Explanation: The correct answer is Environment. The environment exerts selection pressures that influence the success of certain variations over others. Variations that offer a survival advantage in a given environment are more likely to be passed on to future generations. While Species and Population provide the genetic pool from which variations arise, they do not select which variations are successful. Survival is a consequence of how well organisms are adapted to their environment but is not the deciding factor for variation inheritance.

Q35. Hemophilia is a sex-linked _ trait.

• A. Dominant
• B. Codominant
• C. Pleiotropic
• D. Recessive✓

Explanation: Hemophilia is a sex-linked recessive disorder because the gene responsible is located on the X chromosome. In males (XY), the presence of the recessive allele on the X chromosome results in the disorder since there is no corresponding allele on the Y chromosome. In females (XX), a single recessive allele does not cause the disorder because the normal allele on the other X chromosome compensates. Therefore, females need two copies of the recessive allele to express the disorder. The other options are incorrect because they misrepresent the nature of hemophilia's inheritance. It is not dominant, as it does not appear in heterozygous females, nor is it codominant, as both alleles are not equally expressed. It is also not pleiotropic, which involves a single gene influencing multiple traits.

Q36. Which of the following is a type of cell division that plays an important role in evolution?

• A. Meiosis✓
• B. Mitosis
• C. Apoptosis
• D. Amitosis

Explanation: Meiosis is essential for evolution because it produces the genetic variation necessary for natural selection, allowing populations to adapt to changing environments and leading to new species. This variation arises from two key events: crossing over, where homologous chromosomes exchange DNA segments, and independent assortment, where maternal and paternal chromosomes are randomly distributed into gametes. Meiosis also ensures that gametes are haploid (contain half the normal number of chromosomes), so that when they fuse during fertilization, the resulting offspring have the correct diploid chromosome number for the species. In contrast, mitosis involves producing identical cells for growth and repair, apoptosis is cell death, and amitosis is a simpler form of division with no role in genetic variation.

Q37. The "d" and "D" alleles are used for lighter and darker skin colour in humans, respectively. By keeping in view the inheritance pattern of skin colour in human beings(controlled by 3 genes), choose which combination shows medium skin colour from the following picture:

• A. Column A
• B. Column C✓
• C. Column D
• D. Column E

Explanation: The correct answer is Column C because it presents a balanced number of dominant (D) and recessive (d) alleles across all three genes, which results in a medium skin color. In contrast, Column A is incorrect as it shows homozygous recessive alleles (ddd) for all genes, leading to the lightest possible skin color. Column D is incorrect because it fails to show a balance between dominant and recessive alleles, skewing towards either lighter or darker skin. Column E is incorrect as it does not reflect the polygenic nature of skin color inheritance, which involves multiple genes working together, not just a single gene or row.

Q38. There existed two varieties of female freshwater Mollusks in which some were streamlined and some had a high bulge. Over the generations, male freshwater Mollusks learned that high bulge favors more production of offspring. So they started preferring to mate with females having high bulge as compared to streamlined. Will this affect Hardy Weinberg Equilibrium in the population?

• A. No, it will not affect the Hardy-Weinberg equilibrium
• B. Yes, it will affect the Hardy-Weinberg equilibrium✓
• C. It will help to balance the equilibrium
• D. The Hardy-Weinberg equilibrium doesn't apply here

Explanation: The Hardy-Weinberg equilibrium assumes several conditions, one of which is random mating among individuals. When male mollusks develop a preference for females with high bulges, this disrupts random mating, causing changes in allele frequencies over time. This results in a deviation from the expected genotype frequencies predicted by the Hardy-Weinberg principle. Therefore, the preference exhibited by male mollusks affects the equilibrium. The other options are incorrect because they either ignore the importance of random mating or misinterpret the application of the Hardy-Weinberg principle.

Q39. A/An _ is mostly a non-protein chemical compound that is required for the protein’s biological activity.

• A. Active site
• B. Substrate
• C. Cofactor✓
• D. Enzyme

Explanation: The correct answer is 'Cofactor'. A cofactor is a non-protein chemical compound required for the biological activity of some proteins, particularly enzymes. Cofactors can be metal ions or organic molecules and are essential for the catalytic activity of many enzymes.The other options are incorrect because:'Active site' refers to the region of the enzyme where the substrate binds, not a separate chemical compound.'Substrate' is the molecule upon which the enzyme acts, not a non-protein compound required for enzyme activity.'Enzyme' itself is a protein that facilitates biochemical reactions, whereas a cofactor is a non-protein component needed for some enzyme activities.

Q40. All of the following are the characteristics of the kingdom Protista except:

• A. Members can be photosynthetic
• B. Members can be free living
• C. Some members move via flagella
• D. Some members are shaped like rods and termed bacilli✓
• E. Some members spend part of their life cycle inside insects

Explanation: Protists are a group of loosely connected, mostly unicellular eukaryotic organisms that are not plants, animals or fungi. There is no single feature such as evolutionary history or morphology common to all these organisms and they are unofficially placed under a separate kingdom called Protista.Among the given characteristics rod shaped cells called 'Bacilli' (Bacillus singular) are an exclusive classification of Bacteria. Hence, the correct answer is 'Some members are shaped like rods and termed bacilli'.

Q41. Why do some vegetables lose water when salt is applied to them?

• A. Due to the less negative water potential of the external environment than the cell
• B. Due to the more negative water potential of the external environment than the cell✓
• C. Due to the less positive water potential of the external environment than the cell
• D. Due to more positive water potential of the external environment than the cell

Explanation: When salt is applied to vegetables, it dissolves and creates a solution with a more negative water potential. This results in a water potential gradient where the internal water potential of the vegetable cells, being less negative, causes water to move out of the cells into the external environment to reach equilibrium. In simpler words due to the presence of salt the solute potential on the surface of the vegetable increases while the water potential decreases as compared to the inside, due to watch water moves out of the cell to the surface.

Q42. What type of protein is present in eukaryotic DNA but NOT in prokaryotic DNA?

• A. Receptor protein
• B. Glycoprotein
• C. Chromatid protein
• D. Histone protein✓

Explanation: The correct answer is Histone protein. In eukaryotic cells, DNA is wrapped around histone proteins to form chromatin, aiding in the efficient packaging and regulation of DNA. Most prokaryotic cells do not possess histones, with some exceptions like certain Archaea. Receptor proteins, glycoproteins, and chromatid proteins are not involved in DNA organization in this manner. Receptor proteins are for signaling, glycoproteins are for cell communication, and chromatids are DNA structures, not proteins.

Q43. Whenever a muscle contracts, a sarcomere can be shortened up to _ % of its total length.

• A. 15
• B. 25
• C. 35✓
• D. 45

Explanation: The correct answer is 35%. During a maximal muscle contraction, the sarcomere shortens by about 35% of its original length. This is because the actin and myosin filaments slide past each other, reducing the length of the sarcomere. Options 15% and 25% underestimate the typical shortening that occurs, while 45% overestimates it, making 35% the most accurate representation of sarcomere shortening during contraction.

Q44. The second stage of the Prophase of Meiosis, following Leptotene, during which homologous chromosomes begin to pair is called:

• A. Anaphase
• B. Zygotene✓
• C. Diplotene
• D. Pachytene

Explanation: Prophase I of meiosis is divided into five stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis. During Zygotene, the second stage, homologous chromosomes begin to pair up in a process called synapsis, forming structures known as tetrads. This pairing is crucial for genetic recombination in later stages. The other options are incorrect as they refer to different stages where different processes occur: Anaphase involves chromosome separation, Diplotene involves partial separation of homologous chromosomes, and Pachytene involves full synapsis and crossing over.

Q45. Formation of _ will be greater with the faster breakdown of glucose and glycogen to compensate for energy requirements in anaerobic respiration.

• A. Enzymes
• B. Hormones
• C. Lactic acid✓
• D. Fat

Explanation: In anaerobic respiration, when oxygen is scarce, glucose and glycogen are broken down to meet energy needs, resulting in lactic acid as a byproduct. This process does not produce enzymes or hormones as byproducts. Fat metabolism mainly occurs in the presence of oxygen and is not involved in this type of respiration.

Q46. A strand, almost _ nucleotides long is wrapped around a core of _ histone proteins to form a structure called a Nucleosome.

• A. 200 - 4
• B. 200 - 8✓
• C. 200 - 16
• D. 200 - 40

Explanation: The correct answer is 200 - 8. A nucleosome is the fundamental unit of chromatin, consisting of a segment of DNA about 200 nucleotides long wrapped around a histone octamer, which includes eight histone proteins. Specifically, this octamer is formed from two units each of the histone proteins H2A, H2B, H3, and H4. The wrapping of DNA around histones helps in the compact packaging of DNA within the nucleus. Other options are incorrect because they suggest an incorrect number of histone proteins in the core of a nucleosome.

Q47. A group of biologically active molecules formed from amino acids which interact with the surfiace of the lipid bilayer of cell membranes are called:

• A. Integral Proteins
• B. Peripheral Proteins✓
• C. Cell Wall
• D. Plasmodesmata

Explanation: Peripheral proteins, or peripheral membrane proteins, are biologically active molecules formed from amino acids that interact with the surface of the lipid bilayer of cell membranes. Unlike integral membrane proteins, they do not embed within the hydrophobic core of the membrane, but instead attach to the exterior surfaces, often through interactions with integral proteins or the polar heads of lipids. Integral proteins, by contrast, penetrate the lipid bilayer; the cell wall is a structural feature, and plasmodesmata facilitate intercellular communication in plants.

Q48. Transport of three protons through the ATPase complex is required for the production of one _.

• A. Sugar molecule
• B. NADP molecule
• C. ATP molecule✓
• D. NADPH molecule

Explanation: The ATPase complex, also known as ATP synthase, uses the energy from the flow of protons across the mitochondrial membrane to synthesize ATP from ADP and inorganic phosphate (Pi). This process requires the movement of three protons for the production of one ATP molecule. This is a key step in oxidative phosphorylation during cellular respiration. The other options, such as sugar molecules, NADP, and NADPH, are not directly synthesized through the ATPase complex. Instead, they are involved in other metabolic pathways.

Q49. In a forest, there are a lot of plants; trees, shrubs, and herbs. What will the Palm trees face if they grow in the same forest?

• A. Intraspecific competition
• B. Interspecific competition
• C. Environmental competition
• D. All of the above✓

Explanation: In a forest ecosystem, palm trees encounter various forms of competition. Intraspecific competition occurs among palm trees themselves, as they vie for sunlight and nutrients. Interspecific competition arises as they compete with other species, such as shrubs and herbs, for similar resources. Additionally, environmental competition is present due to the limited availability of resources like light, water, and soil nutrients, which are essential for all plant life. Therefore, option D, 'All of the above,' is the correct answer. Other options are incorrect as they only address one type of competition.

Q50. Which one of the following options is NOT an example of genetic engineering?

• A. Insulin-producing bacteria
• B. Oil-eating bacteria
• C. Photosynthetic bacteria✓
• D. Metal-extracting bacteria

Explanation: The correct answer is Option C: Photosynthetic bacteria. These bacteria are not a product of genetic engineering; they occur naturally and perform photosynthesis to generate energy. In contrast, insulin-producing bacteria (Option A) are engineered to produce insulin, oil-eating bacteria (Option B) are modified to degrade oil, and metal-extracting bacteria (Option D) are designed to extract metals from ores. All these examples involve human intervention to alter the bacteria's natural capabilities, unlike photosynthetic bacteria.

Q51. Pick the odd one out in the following picture.

• A. A
• B. B
• C. C✓
• D. D

Explanation: The correct answer is Option C. In translation, the primary components required are tRNA, mRNA, and ribosomes. RNA polymerase, which is present in Option C, is involved in transcription, where it synthesizes RNA from a DNA template. Therefore, Option C is the odd one out as it includes a component not used in translation. Options A, B, and D include elements relevant to translation, confirming their appropriateness within the context of protein synthesis.

Q52. While working in a laboratory, before studying a sample under the microscope, it was immersed in a dye solution to obtain _.

• A. Magnification
• B. Image
• C. Match
• D. Contrast✓

Explanation: Staining is used to enhance contrast in microscopic samples, making it easier to distinguish between different structures and components within the sample. By increasing contrast, stains help highlight specific features that might otherwise be difficult to see. The other options are unrelated to the purpose of using dyes: magnification is achieved by the microscope's lenses, images are the visual outcomes, and matching is a comparison process, not related to the dye's function.

Q53. Pathway of energy production from food used by muscles is:

• A. Food → ATP → creatine phosphate → protein
• B. Food → glycogen → ATP → creatine phosphate
• C. Food → glycogen → creatine phosphate → ATP✓
• D. Food → protein → creatine phosphate → ATP

Explanation: The correct pathway for energy conversion in muscles starts with food being broken down into glycogen. Glycogen is then converted to glucose, which is used to regenerate creatine phosphate. Creatine phosphate is a quick source of energy, which is then metabolized to form ATP, the main energy currency of the cell. Options A, B, and D are incorrect because they misrepresent the sequence of energy transformations or the role of the protein in this context.

Q54. A_ is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent.

• A. Cellular anaerobe
• B. Respiratory anaerobe
• C. Obligate anaerobe
• D. Facultative anaerobe✓

Explanation: Facultative anaerobes are versatile organisms that can produce ATP through aerobic respiration when oxygen is available, and switch to fermentation in its absence. This adaptability allows them to survive in varying oxygen conditions. In contrast, obligate anaerobes cannot tolerate oxygen and rely solely on anaerobic processes. The terms 'cellular anaerobe' and 'respiratory anaerobe' are not used in microbiology to classify organisms based on their oxygen requirements.

Q55. Choose the best group from the following to produce transgenic plants in the laboratory:

• A. Group A✓
• B. Group B
• C. Group B and C
• D. Group C

Explanation: Group A is the correct choice as it comprises the essential genetic engineering tools: restriction enzymes to cut DNA and DNA ligases to insert the genetic material into plant cells, enabling the development of transgenic plants. Group B lacks plasmids, vital for DNA transfer, and Group C includes items such as autoradiographs that are unrelated to the genetic engineering process.

Q56. Which one of the following is not a mode of transmission of AIDS?

• A. Through unsterilized needles
• B. Through contact with open wounds
• C. Through blood transfusion
• D. Through holding hands✓

Explanation: The correct answer is Option D: Through holding hands. AIDS is caused by the HIV virus, which is transmitted through the exchange of certain body fluids such as blood, semen, vaginal fluids, and breast milk from an infected person. Casual contact, such as holding hands, does not involve the exchange of these fluids and therefore cannot transmit the virus.Option A: Through unsterilized needles and Option C: Through blood transfusion are incorrect because both involve direct exposure to infected blood, a known mode of HIV transmission. Option B: Through contact with open wounds is also incorrect because if the contact involves infected blood or bodily fluids, transmission is possible.

Q57. The following results of a cross between two individuals shown in the picture are: Which statement describes the children of the cross?

• A. One child is homozygous dominant, while the other exhibits a dominant phenotype but has a parent with a recessive phenotype.
• B. Two child is homozygous recessive, and the other exhibits a dominant phenotype but has a parent with a recessive phenotype.✓
• C. One child is homozygous recessive, and the other exhibits a dominant phenotype but has a sibling with a recessive phenotype.
• D. One child is homozygous recessive, and another exhibits a recessive phenotype, but has a parent with a dominant phenotype.

Explanation: The correct answer is Option B. In a Mendelian cross involving one parent who is homozygous recessive and another who is heterozygous, one offspring can be homozygous recessive, receiving recessive alleles from both parents, resulting in a recessive phenotype. The other offspring can be heterozygous, inheriting a dominant allele from one parent and a recessive allele from the other, which results in a dominant phenotype. Options A and D are incorrect due to incorrect assumptions about the potential genotypes of the offspring. Option C is misleading as it introduces unnecessary sibling relationships that do not contribute to solving the question.

Q58. An enzyme is responsible for copying a DNA sequence into an RNA sequence.

• A. Restriction enzyme
• B. Reverse transcriptase
• C. RNA polymerase✓
• D. DNA polymerase

Explanation: The correct answer is RNA polymerase. This enzyme is crucial for the transcription process, where it reads the DNA template and synthesizes a complementary RNA strand. In contrast, restriction enzymes are used in molecular biology to cut DNA at specific sequences. Reverse transcriptase operates in the opposite direction, creating DNA from an RNA template, typically in retroviruses. DNA polymerase is responsible for DNA replication, assembling a new DNA strand from a DNA template during cell division.

Q59. The following picture is of _ which separates based on their size and speed.

• A. Cloning
• B. Recombinant DNA technique
• C. Cell culture
• D. Gel Electrophoresis✓

Explanation: Gel electrophoresis is the correct answer as it is specifically designed to separate molecules such as DNA, RNA, or proteins based on their size and charge. The technique involves loading samples into a gel and applying an electric current, causing smaller molecules to move faster and farther than larger ones. This process helps in analyzing the molecular structure and size of biological samples.Cloning, recombinant DNA techniques, and cell culture do not involve the separation of molecules by size or speed. Cloning creates identical copies of organisms or cells, recombinant DNA techniques combine DNA from different sources, and cell culture grows cells in a controlled environment.

Q60. When a plant cell receives a signal for death, it commits suicide by rupturing:

• A. Nucleus
• B. Cell membrane
• C. Tonoplast✓
• D. Chloroplast

Explanation: In plant cells, programmed cell death (PCD) is an orderly process that involves the rupture of the tonoplast, the membrane surrounding the vacuole. This rupture releases vacuolar contents, including enzymes, into the cell, leading to its demise. The tonoplast's rupture is crucial as it allows the enzymes to interact with other cellular components, leading to cell death. The nucleus, cell membrane, and chloroplasts are not involved in this specific rupture process. The nucleus manages genetic information, the cell membrane maintains cellular integrity, and chloroplasts function in photosynthesis, none of which directly cause cell death through rupturing in PCD.

Q61. Cell permeability and transport processes of cell membrane depend upon its _ component.

• A. Phospholipid✓
• B. Carbohydrates
• C. Polysaccharide
• D. Cellulose

Explanation: The permeability of the cell membrane and its permeability depends upon the phospholipid content of that membrane. All other chemical components mentioned (carbohydrates, polysaccharides, and cellulose) are not part of the cell membrane.

Q62. Which disorder among the following cannot be detected by amniocentesis?

• A. Hemophilia
• B. Heart defects✓
• C. Tay-Sachs disease
• D. Cystic fibrosis

Explanation: This question is simply choosing the odd one out. Heart defects are not genetic. Amniocentesis is used to detect genetic defects like those mentioned in other options.

Q63. What is the phenomenon shown in the following picture?

• A. Abscission
• B. Senescence
• C. Apical dominance✓
• D. Ripening

Explanation: As it can be seen in the diagram above the apical end is active and the lateral end is dormant. The apical bud is active, growing, and dominant as it can be seen growing far more than lateral buds. Therefore it can be said there is apical dominance in this plant.Option A is wrong because abscission is the natural detachment of parts of a plant, typically dead leaves and ripe fruit. Option B is wrong because of senescence, the condition or process of deterioration with age. Option D is wrong because ripening refers to the maturation of fruits.

Q64. In a laboratory, while working on a new species of fish, it is found that the fish has two varieties, red and brown. It was determined by another group of scientists in another laboratory that brown is a dominant color in this species. If we have brown fish with us in the laboratory, how can we determine whether they are homozygous or heterozygous for the trait?

• A. Breed this fish with a redfish and check F1 generation✓
• B. Breed this fish with a redfish and check F2 generation
• C. Breed this fish with a brown fish and check F1 generation
• D. Breed this fish with a brown fish and check F2 generation

Explanation: To find out whether the given species is homozygous or heterozygous we should breed it with species having a recessive phenotype and check the first (F1) generation. If even one of the offsprings from the F1 generation have a recessive phenotype that means our species was heterozygous or else homozygous.

Q65. Which one is NOT true for coordination in animals?

• A. Transmission by the nervous system is short-lived, whereas transmission by the hormonal system is long-lasting
• B. The nervous system uses electrical impulses to send signals through neurons, whereas hormonal coordination uses chemical messengers transported in the blood
• C. Responses are often permanent in the hormonal system, but temporary and reversible in the nervous system
• D. In the nervous system, secretory chemicals are released in the blood, while in the hormonal system, secretory chemicals are released in extracellular fluids✓

Explanation: The correct answer is Option D. In the nervous system, neurotransmitters are released at synapses between neurons, not into the bloodstream. Hormones, however, are released into the blood by endocrine glands. The other options correctly describe the characteristics of the nervous and hormonal systems in terms of signal duration, nature of transmission, and response permanence.

Q66. Plant pigments responsible for red, yellow, and orange colors in many fruits and vegetables are:

• A. Chlorophyll a
• B. Chlorophyll b
• C. Carotenoids✓
• D. Cellulose

Explanation: The correct answer is Carotenoids. These pigments impart red, yellow, and orange hues to many fruits and vegetables. They play a significant role in plant health and offer antioxidant benefits to humans. Chlorophyll a and b are primarily green pigments associated with photosynthesis, not with the vibrant colors in question. Cellulose, while important for structural integrity in plants, does not contribute to coloration.

Q67. What does the following picture show?

• A. Motor Neuron
• B. Sensory Neuron✓
• C. Interneuron
• D. Nerve

Explanation: The diagram illustrates a sensory neuron. The defining feature is the cell body, which connects to the dendrites via dendron processes. This structure is specific to sensory neurons and is not found in motor neurons, where the cell body directly attaches to dendrites. Interneurons are characterized by processes that are similar in size to the cell body, which is not evident here. Lastly, the term 'nerve' refers to a collection of neurons, whereas the image shows only one neuron.

Q68. As a result of competition among friends, Ahmed eats a lot of pakoras, resulting in a rise of salts in the blood, to compensate_ is triggered in the body.

• A. Positive feedback
• B. Negative feedback✓
• C. Internal feedback
• D. External feedback

Explanation: The correct answer is Negative feedback. This mechanism is crucial for maintaining homeostasis in the body. When there is a rise in salts in the blood, negative feedback mechanisms are triggered to restore balance, such as by increasing water retention or adjusting salt excretion, thus counteracting the initial change. In contrast, Positive feedback would further increase the change rather than compensating for it, and both Internal feedback and External feedback are not relevant terms in the context of physiological regulation for homeostasis.

Q69. Due to the presence of _, the reabsorption of water is increased in the collecting ducts.

• A. Mg
• B. ADH✓
• C. Kidney stones
• D. High pH

Explanation: Antidiuretic hormone (ADH), also known as vasopressin, is crucial in regulating water balance in the body. It enhances water reabsorption in the collecting ducts of the kidneys, thereby reducing water loss in urine and helping maintain blood pressure. Magnesium, kidney stones, and high pH do not directly contribute to water reabsorption in the collecting ducts, making them incorrect choices for this question.

Q70. When a color-blind male marries a normal female, what will be the chances of colorblindness in his grandsons, if his daughter is married to a normal male?

• A. 16%
• B. 25%
• C. 50%✓
• D. 100%

Explanation: The correct answer is 50%. When a color-blind male marries a normal female, all their daughters will be carriers of the color-blind gene because they inherit the X chromosome carrying the gene from their father. When one of these carrier daughters marries a normal male, each son has a 50% chance of inheriting the X chromosome carrying the color-blind gene, resulting in a 50% chance of being color-blind. The other options are incorrect because they do not correctly apply the rules of X-linked recessive inheritance.

Q71. Humans are _ and mostly use _ thermoregulation.

• A. Ectotherm, behavioral
• B. Endotherm, physiological✓
• C. Ectotherm, physiological
• D. Endotherm, behavioral

Explanation: Humans are classified as endotherms because they maintain a stable internal temperature through internal heat production, primarily using physiological mechanisms like sweating to cool down or shivering to warm up. The incorrect options highlight either the use of external heat sources (characteristic of ectotherms) or behavioral strategies as the primary method of thermoregulation, which is not the main strategy for humans.

Q72. Read the code mentioned in the following picture and arrange the sequence of all five codons in which Leucine is at 3rd position. while isoleucine is in 4th position. Keep in mind that CUU is the code for Leucine, AUU for Isoleucine and CAA or glutamine.

• A. UAA-AUG-CAA-CUU-AUU
• B. AUG-CAA-CUU-AUU-UAA✓
• C. AUU-AUG-CAA-CUU-UAA
• D. AUG-UAA-CUU-AUU-CAA

Explanation: The correct sequence is AUG-CAA-CUU-AUU-UAA. This sequence begins with a start codon (AUG) and ends with a stop codon (UAA), adhering to the standard structure of mRNA translation. Within this sequence, CUU (coding for Leucine) is correctly placed in the third position, and AUU (coding for Isoleucine) is correctly positioned in the fourth. Other options fail to meet these criteria: Option A incorrectly places CUU and AUU, Option C misplaces AUU, and Option D incorrectly incorporates the stop codon UAA in a position meant for a coding sequence.

Q73. Because it is capable of dissolving more substances than any other liquid _ is called the "universal solvent".

• A. Ethane
• B. Alcohol
• C. Chloroform
• D. Water✓

Explanation: Water is called the 'universal solvent' because of its unique chemical properties that allow it to dissolve a wide range of substances. The polarity of water molecules enables them to form hydrogen bonds with other molecules, facilitating the dissolution process. Other options like ethane, alcohol, and chloroform are limited in their solvent capabilities due to their chemical structures and lack of polarity. Ethane is a non-polar hydrocarbon, alcohols are somewhat polar but less versatile than water, and chloroform is an organic compound with limited solubility scope.

Q74. Which animals support Darwin's view of inheritance of desirable variation?

• A. Giraffe
• B. Galapagos finches✓
• C. Snake
• D. All of these

Explanation: Galapagos is an island where Darwin observed almost 13 types of finchis with distinct traits.

Q75. Interphase is a phase of the cell cycle defined only by the absence of _.

• A. Enzymes
• B. DNA
• C. Replication
• D. Cell division✓

Explanation: Interphase is the phase of the cell cycle where the cell prepares for division by growing and replicating its DNA. It is defined by the absence of cell division, which occurs in the subsequent phases of the cell cycle.Interphase is the phase of the cell cycle when a cell grows, replicates its DNA, and prepares for mitosis and cell division. It is the longest phase, comprising G1, S, and G2 stages. In G1, the cell grows and copies organelles. During S, DNA is synthesized, and chromosomes duplicate. In G2, the cell continues growing, creates proteins and organelles, and checks for errors before mitosis begins. In contrast, enzymes and DNA are present and actively involved in processes during interphase. DNA replication is a key event of interphase, not an absence. Therefore, the correct answer is that interphase is defined by the absence of cell division.

Q76. Juxta-medullary nephrons are present only in:

• A. Fishes and amphibians
• B. Amphibians and birds
• C. Birds and mammals✓
• D. Mammals and fishes

Explanation: Juxtamedullary nephrons are essential for the concentration of urine and are found only in birds and mammals due to their need for efficient water conservation. These nephrons have long loops of Henle that extend deep into the renal medulla, enabling the production of concentrated urine. Other options are incorrect because either the organisms don't possess juxtamedullary nephrons or the presence is not consistent across the group.

Q77. What does 'a' in the following picture show?

• A. Cellular pathway
• B. Symplast pathway✓
• C. Apoplast pathway
• D. Water pathway

Explanation: The correct answer is the symplast pathway, which refers to the transport of substances through the cytoplasm of plant cells, connected by plasmodesmata. This allows for direct cell-to-cell transport. The apoplast pathway, on the other hand, involves movement through cell walls and spaces outside the plasma membrane, not through plasmodesmata. The cellular pathway is a broader term that encompasses various biochemical interactions within a single cell, and the water pathway pertains to the overall water cycle in nature, rather than specific plant mechanisms.

Q78. In semi-conservative replication, which of the following is true regarding the separation of two strands?

• A. The primary structure is preserved, while the secondary structure is altered.✓
• B. The secondary structure is preserved, while the primary structure is altered.
• C. Both the primary and secondary structures remain unchanged.
• D. Both the primary and secondary structures are disrupted.

Explanation: In semi-conservative replication, the DNA molecule separates into two strands, each serving as a template for a new complementary strand. This ensures that the primary structure, or the sequence of nucleotides, is conserved in each of the daughter molecules. However, the secondary structure, formed by hydrogen bonds between the two DNA strands, is temporarily disrupted during this process to allow the strands to separate and be replicated. Thus, the correct option is that the primary structure is preserved, while the secondary structure is altered. The other options are incorrect as they do not accurately describe the conservation of the primary structure and the disruption of the secondary structure during DNA replication.

Q79. What is Molecule "a" in the following picture?

• A. Host cell
• B. Donor cell
• C. Restriction enzyme
• D. Recombinant DNA✓

Explanation: Recombinant DNA is a form of artificial DNA that is created by combining two or more sequences that would not normally occur together. In genetic engineering, this process involves inserting a segment of DNA from one organism into the DNA of another organism, creating new genetic combinations that are of value to science, medicine, agriculture, and industry. The other options describe components or tools used in the process of creating recombinant DNA but do not identify the specific molecule depicted in the question.

Q80. A group of immune cells that mediate the cellular immune response by processing and presenting antigens for recognition of certain other cells or immune systems is called _.

• A. Natural killer cells
• B. Interferons
• C. Antigen-presenting cells✓
• D. Vaccines

Explanation: Antigen-presenting cells (APCs) like macrophages and dendritic cells display antigens to T-cells, activating immune response.

Q81. Name the type of the following chromosome:

• A. Metacentric
• B. Submetacentric
• C. Telocentric
• D. Acrocentric✓

Explanation: An acrocentric chromosome is characterized by a centromere that is positioned near one end, resulting in a long arm and a short arm. This configuration allows for the formation of a satellite, which is often associated with nucleolus organizer regions in some chromosomes. Unlike metacentric, submetacentric, or telocentric chromosomes, acrocentric chromosomes are distinguished by their unique centromere positioning. Humans possess five pairs of acrocentric chromosomes, namely chromosomes 13, 14, 15, 21, and 22.

Q82. The complete aerobic oxidation of glucose results in the synthesis of as many _ molecules of ATP.

• A. 16
• B. 26
• C. 36✓
• D. 46

Explanation: The complete aerobic oxidation of one molecule of glucose results in the synthesis of approximately 30-38 molecules of ATP. This includes ATP generated through glycolysis (2 ATP), the citric acid cycle (2 ATP), and oxidative phosphorylation (electron transport chain and chemiosmosis, which produce the majority of ATP). The number often cited is 36, but it can vary based on cellular conditions such as the efficiency of electron transport and the shuttle systems used for transporting electrons into the mitochondria. Therefore, the correct answer is approximately 36 ATP, while the other options do not accurately reflect the typical ATP yield from aerobic respiration.

Q83. Primary function of fats in aquatic mammals is _ and in terrestrial mammals is _.

• A. Insulating body temperature, aiding buoyancy
• B. Providing energy storage, insulating body temperature
• C. Conserving heat, storing energy✓
• D. Providing warmth, aiding movement

Explanation: In aquatic mammals, such as whales and seals, fats serve a crucial role in thermoregulation by conserving heat in cold water environments, thanks to a thick layer of blubber that provides excellent insulation. In terrestrial mammals, fats are primarily used for energy storage. They act as a reserve of energy that can be metabolized when food resources are scarce. This energy storage function is vital for survival during periods of food scarcity or when energy demands increase. Options A and D are incorrect because they do not accurately describe the primary functions of fats in both environments.

Q84. Crossing over is an exchange of genes between _ resulting in a mixture of parental characteristics in offspring.

• A. Sister chromatids
• B. Non-homologous chromosomes
• C. Sex chromosomes
• D. Homologous chromosomes✓

Explanation: Crossing over is the exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I of meiosis.Crossing over is the biological process during meiosis (sexual reproduction) where homologous chromosomes exchange genetic material, leading to the creation of recombinant chromosomes and increased genetic variation in gametes like sperm and eggs. This process involves the physical swapping of segments between non-sister chromatids of paired homologous chromosomes, resulting in unique combinations of maternal and paternal genes in the resulting sex cells, which is crucial for the diversity and adaptation of a species. This process increases genetic diversity by producing new combinations of alleles in the daughter cells. Sister chromatids, being identical, do not engage in crossing over. Similarly, non-homologous chromosomes do not pair up for crossing over, and while sex chromosomes may participate in crossing over, it is the homologous chromosomes that are primarily involved in this genetic exchange process.

Q85. All of the following are reflex actions EXCEPT:

• A. Change in the size of the pupil in response to light
• B. Swallowing of the bolus✓
• C. Sudden jerky withdrawal of hand when pricked
• D. Knees jerk in response to a blow

Explanation: Reflex actions are involuntary and instantaneous responses to stimuli. The change in pupil size, jerky withdrawal of the hand, and knee jerk are all reflex actions because they occur automatically and without conscious thought. However, swallowing of the bolus, while it begins with a reflexive component, is primarily a voluntary action because it requires conscious control, especially after the initial trigger, making it not purely reflexive.

Q86. What is in q2 Hardy Weinberg equilibrium?

• A. Frequency of the dominant allele
• B. Frequency of the recessive allele
• C. Frequency of the homozygous recessive genotype✓
• D. Number of both alleles

Explanation: In Hardy-Weinberg equilibrium, the equation p² + 2pq + q² = 1 is used to describe the distribution of genotypes in a population. Here, p² represents the frequency of the homozygous dominant genotype, 2pq represents the frequency of the heterozygous genotype, and q² represents the frequency of the homozygous recessive genotype. Thus, the correct interpretation of q² is the frequency of individuals with the homozygous recessive genotype. Other options are incorrect because they misinterpret q² as relating to allele frequency or the number of alleles, rather than the specific genotype frequency it represents.

Q87. The genome of viruses is composed of

• A. DNA
• B. RNA
• C. Protein
• D. Either DNA or RNA✓

Explanation: Viruses are unique in that their genomes are composed of either DNA or RNA. This diversity in genetic material is a fundamental characteristic used to classify viruses. While some viruses have DNA genomes, such as herpesviruses, others have RNA genomes, like the influenza virus. This genetic material carries the instructions for replication and the synthesis of viral proteins. Proteins, on the other hand, serve structural or functional roles within the virus but are not part of the genetic material itself. Therefore, the correct answer is Option D: Either DNA or RNA.

Q88. Carbon dioxide fixation can be enhanced by enhancing the efficiency of:

• A. Auxins
• B. RuBisCO✓
• C. Lactoferrin
• D. Agrobacterium

Explanation: Carbon dioxide fixation in photosynthesis is primarily facilitated by the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). RuBisCO catalyzes the first major step of the Calvin Cycle, where carbon dioxide is fixed into an organic molecule, ribulose bisphosphate (RuBP). Enhancing the efficiency of RuBisCO can thus improve the overall process of carbon fixation.Auxins, while important for plant growth, do not participate in carbon fixation. Lactoferrin is unrelated to photosynthesis, and Agrobacterium, although useful in genetic engineering, does not play a role in carbon fixation.

Q89. Label the following phenomenon

• A. Exocytosis
• B. Osmosis
• C. Diffusion
• D. Phagocytosis.✓

Explanation: The diagram shows phagocytosis, which is the process by which a cell uses its plasma membrane to engulf a large particle, giving rise to an internal compartment called the phagosome. It is one type of endocytosis.Exocytosis is a form of active transport and bulk transport in which a cell transports molecules out of the cell. Osmosis is the movement of water molecules down the water potential gradient into or out of the cell. Diffusion is the movement of substances down the concentration gradient into or out of the cell.

Q90. Which of the following is NOT true for a gene?

• A. A gene is a sequence of nucleotides in DNA.
• B. A gene is the basic unit of heredity.
• C. A gene codes for a molecule that has a function.
• D. A gene expresses to form chromosomes.✓

Explanation: The correct answer is D. Genes are segments of DNA that do not express themselves to form chromosomes. Instead, chromosomes are structures that contain many genes. Options A, B, and C are accurate descriptions of what genes are and what they do: they are sequences of nucleotides, the basic units of heredity, and they code for molecules with specific functions.

Q91. The function of cilia in the respiratory passage is to keep the airways clear of:

• A. Carbon dioxide
• B. Oxygen
• C. Dust✓
• D. Carbon Monoxide

Explanation: Cilia, tiny hair-like structures lining the respiratory passages, play a crucial role in clearing dust and other particulate matter by moving mucus out of the airways. This action prevents inhaled particles from reaching the lungs. Goblet cells produce mucus that traps these particles, which cilia then transport out of the airway through rhythmic beating. Cilia do not clear gases like oxygen, carbon dioxide, or carbon monoxide from the respiratory system; these gases are involved in gas exchange processes but are not removed by ciliary action.

Q92. _ is the storage form of carbohydrate in animals and humans which is equivalent to the _ in plants.

• A. Glycogen, cellulose
• B. Starch, cellulose
• C. Glycogen, starch✓
• D. Starch, glycogen

Explanation: The correct answer is C: Glycogen is the storage form of carbohydrates in animals, while starch is the corresponding storage form in plants. Both glycogen and starch are polysaccharides, meaning they are composed of long chains of glucose molecules, allowing them to store energy efficiently. Option A is incorrect because cellulose is a structural component, not a storage carbohydrate. Option B is incorrect for the same reason regarding cellulose. Option D reverses the roles of starch and glycogen.

Q93. As an essential element in living organisms, _ ion is playing an important role in insulin secretion, the release of neurotransmitters, muscle contraction, and heartbeat regulation.

• A. Sodium
• B. Potassium
• C. Calcium✓
• D. Chloride

Explanation: Calcium ions are critical in facilitating the release of neurotransmitters and insulin. They enter cells in response to specific signals and promote vesicular transport to the cell membrane, culminating in exocytosis. Additionally, calcium ions interact with proteins like troponin, playing a pivotal role in muscle contraction. Sodium and potassium are essential for nerve impulse transmission, while chloride maintains fluid and pH balance but does not directly influence insulin secretion or neurotransmitter release.

Q94. What are a and b in the following picture?

• A. Allele and allele✓
• B. Allele and gene
• C. Gene and gene
• D. Mutation and gene

Explanation: In the context of genetics, an allele is a variant form of a given gene. When looking at traits such as flower color, there can be multiple alleles responsible for the variations seen in the trait. In this question, both a and b represent different alleles of the same gene, which determine the colors purple and white in flowers. The other options are incorrect because: 'Allele and gene' implies one is a variation and the other is the gene itself, which is incorrect here; 'Gene and gene' does not specify the variations; 'Mutation and gene' misrepresents the concept, as mutations are changes in DNA, not variations of a gene.

Q95. Arrange the following according to the level of protein structures:a) lysozyme, b) haemoglobin, c) Individual chains of insulin, d) hairs

• A. d, a, c, b
• B. a, b, c, d
• C. d, c, b, a
• D. c, d, a, b✓

Explanation: The correct order is c, d, a, b:Insulin: This is a hormone composed of two peptide chains with a specific amino acid sequence, representing its primary structure.Hair (Keratin): The structural protein keratin in hair forms alpha-helices, indicative of a secondary structure.Lysozyme: This enzyme has a complex three-dimensional folding, typical of a tertiary structure.Hemoglobin: Composed of four subunits, hemoglobin exemplifies a quaternary structure.Other options incorrectly sequence the proteins based on their structural complexity.

Q96. Which is a correct description of the role of calcium ions in the neuromuscular system?

• A. Exchanged with sodium ions through co-transport channels at axon surfaces during the reestablishment of a resting potential after an action potential
• B. Diffuses through gated ion channels in presynaptic membranes of excitatory neurons, prompting vesicles to move to the presynaptic membrane as an impulse arrives✓
• C. Exchanged with chloride ions at the postsynaptic membrane, altering membrane potential in inhibitory neurons
• D. Actively pumped out of axons at nodes of Ranvier in myelinated neurons, which is the main cause of the potential difference that is maintained during the resting potential

Explanation: The role of calcium ions in the neuromuscular system is crucial during synaptic transmission. When an action potential reaches the synaptic knob, it triggers the opening of voltage-gated Ca2+ channels in the presynaptic membrane. Calcium ions then diffuse into the neuron, causing synaptic vesicles filled with neurotransmitters to move towards and fuse with the presynaptic membrane, leading to neurotransmitter release into the synaptic cleft by exocytosis. This process does not involve sodium or chloride ions, nor does it relate to the maintenance of resting potentials, which are handled by different ion channels and pumps.

Q97. In eggs, Ca+2 plays an important role especially at the time of fertilization. Therefore _ are present in many thousand numbers inside the cell membrane.

• A. Ribosomes
• B. Chloroplast
• C. Mitochondria
• D. Endoplasmic Reticulum✓

Explanation: The Endoplasmic Reticulum (ER) serves as a major reservoir of calcium ions (Ca2+) in cells. During fertilization, there is a need for precise regulation and release of Ca2+, which the ER facilitates. Ribosomes, while essential for protein synthesis, do not store calcium. Chloroplasts are irrelevant in animal cells, and mitochondria, though involved in calcium signaling, do not primarily store Ca2+ like the ER does.

Q98. Genetic equilibrium is a:

• A. Change of allele and gene frequency in a population
• B. Stability of allele and gene quantity in a population
• C. Change of allele and gene number in a population
• D. Stability of allele and gene frequency in a population✓

Explanation: Genetic equilibrium refers to a condition where the allele and gene frequencies in a population remain constant over time, indicating no evolutionary change occurring. This stability is typically due to factors such as large population size, random mating, no mutation, migration, or selection. Option D is correct as it accurately defines this state of balance. The other options incorrectly describe scenarios where changes in allele frequencies or gene quantities occur, which are indicative of evolutionary processes rather than equilibrium.

Q99. Choose the term from the following which is NOT a part of gene therapy?

• A. Bone marrow transplant
• B. Retrovirus
• C. DNA Fingerprinting✓
• D. Somatic cells

Explanation: DNA Fingerprinting is not a component of gene therapy. It is a forensic tool used for identifying individuals based on their unique DNA profiles. In contrast, gene therapy involves methods like bone marrow transplants, which replace defective cells; retroviruses, which deliver therapeutic genes into cells; and somatic cells, which can be genetically modified to correct disorders. These elements are integral to the process of gene therapy, which aims to treat or cure genetic diseases.

Q100. The synapse formed at the sites where the terminal branches of the axon of a motor neuron conduct to a target muscle cell is called:

• A. Sensory end plate
• B. Synapse end plate
• C. Motor end plate✓
• D. Postsynaptic membrane

Explanation: The motor end plate is the specialized area at the neuromuscular junction where the axon terminal of a motor neuron forms a synapse with a muscle fiber. It is responsible for transmitting neural signals to muscle cells, resulting in muscle contraction. The term sensory end plate is associated with sensory neurons, not motor neurons. Synapse end plate is not a recognized term in neuroscience. The postsynaptic membrane refers generically to the membrane receiving neurotransmitters at any synapse, not specifically at neuromuscular junctions.

Q101. Which of the following gases is used for welding purpose:

• A. Ethene
• B. Ethane
• C. Propane
• D. Ethyne✓

Explanation: Ethyne, or acetylene, is the correct choice for welding purposes. It is favored in the industry for its ability to produce a flame temperature over 3600K when burned with oxygen, allowing it to cut and weld metals efficiently. The other gases listed, such as ethene, ethane, and propane, do not reach the necessary temperatures or have other primary uses that do not include welding.

Q102. The chief ore of aluminium is:

• A. Na3AlF6
• B. Al2O3.nH2O
• C. Al2O3
• D. Al2O3.2H2O✓

Explanation: The chief ore of aluminium is bauxite, with the chemical formula Al2O3.2H2O. Bauxite is primarily composed of aluminium hydroxide minerals, which are processed to produce pure aluminium. The other options are related to aluminium but are not the primary ore. Cryolite (Na3AlF6) is used in the extraction process, not as an ore. Alumina (Al2O3) is a refined product derived from bauxite, while Al2O3.nH2O refers to various alumina hydrates but not specifically to bauxite.

Q103. Sp hybrid orbitals are formed by the mixing of:

• A. One s and two p
• B. One s and three p
• C. One s and one p✓
• D. Two s and two p

Explanation: In sp hybridization, one s orbital and one p orbital hybridize to form two sp orbitals, each possessing 50% s character and 50% p character. This type of hybridization is typical in linear molecular geometries, where the central atom is bonded to two other atoms. Option A describes sp2 hybridization, Option B describes sp3 hybridization, and Option D is not a valid hybridization scheme.

Q104. Which one of the following bonds has the highest bond energy?

• A. .C-C
• B. .C ≡ C
• C. N ≡ N✓
• D. H-F

Explanation: Triple bonds are stronger than single and double bonds, for understandable reasons. A nitrogen-nitrogen triple bond is stronger than a carbon-carbon triple bond because as we know that in the periodic table as we move from left to right the atomic sizes of elements decrease, this is due to the addition of electrons in the valence shell which increases nuclear charge. Carbon and nitrogen both elements are present in the same period but nitrogen (Z=7) is placed next to carbon (Z=6) thus it means the size of nitrogen is smaller than that of carbon and thus both the nitrogen atoms are much closer to each other unlike in case of carbon and hence more energy is required to break N-N triple bond compared to C-C triple bond.

Q105. Diamond is a bad conductor because it:

• A. Has a tightly bonded structure
• B. Has high density
• C. Has no free electrons available for conduction✓
• D. Is transparent to light

Explanation: Diamond is a poor electrical conductor because it lacks free electrons. In materials, electrical conduction occurs when electrons can move freely. In diamond, each carbon atom forms four strong covalent bonds with neighboring carbon atoms, creating a stable lattice with no free electrons. Therefore, diamond cannot conduct electricity. In contrast, a good conductor would have free electrons that can move easily through the material.The other options are incorrect because:A tightly bonded structure (Option A) contributes to diamond's hardness, not its electrical properties.High density (Option B) relates to the physical mass per unit volume and has no direct impact on electron mobility.Transparency to light (Option D) is about optical properties, not electrical conductivity.

Q106. Ethers show the phenomenon of:

• A. Position isomerism
• B. Functional group isomerism
• C. Metamerism✓
• D. Cis-trans isomerism

Explanation: Metamerism is a type of isomerism in which molecules have the same molecular formula but different alkyl groups around the functional group.For example,CH3-CH2-O-CH2-CH3 and CH3-O-CH2-CH2-CH3 are two metamers of each other.

Q107. The nature of positive rays depends on:

• A. The nature of the electrode:
• B. The nature of the discharge tube
• C. The nature of the residual gas.✓
• D. The shape of the electrode

Explanation: Positive rays, also known as canal rays, are produced in a discharge tube and consist of positively charged ions originating from the residual gas present in the tube. The characteristics of these rays, such as their mass-to-charge ratio, depend on the type of gas used. This is why the nature of the residual gas is crucial. The other factors, such as the nature or shape of the electrode and the design of the discharge tube, do not affect the composition or properties of the positive rays, as they do not influence the ionization of the gas.

Q108. The net heat change in a chemical reaction is the same whether it is brought about in two or more different ways in one or several steps. This is known as:

• A. Henry's law
• B. Hess's law✓
• C. Joule's principle
• D. Dalton's law

Explanation: Hess's Law is a fundamental principle in thermochemistry, asserting that the total enthalpy change during a chemical reaction is the same regardless of the number of steps in which the reaction is carried out, because enthalpy is a state function. This means that it depends only on the initial and final states of the system, not on the path taken.Henry's law, Dalton's law, and Joule's principle all deal with different principles: Henry's law is about gas solubility in liquids, Dalton's law is about partial pressures in gas mixtures, and Joule's principle is about the conversion of electrical energy to heat in conductors. None of these involve the calculation of enthalpy changes in chemical reactions.

Q109. The volume occupied by 1.4g of N2 at S.T.P is:

• A. 2.24 dm3
• B. 22.4 dm3
• C. 1.12 dm3✓
• D. 112 dm3

Explanation: To determine the volume occupied by 1.4g of N2 at standard temperature and pressure (STP), we need to use the ideal gas law equation: PV = nRT Where: P = pressure (in atm) V = volume (in dm3) n = number of moles of gas R = ideal gas constant (0.0821 dm3.atm/mol.K) T = temperature (in Kelvin) At STP, the pressure (P) is 1 atm, and the temperature (T) is 273.15 K (0 degrees Celsius) Now, we need to calculate the number of moles of N2 .The molar mass of N2 (nitrogen gas) is: = 2 * molar mass of nitrogen (N) = 2 * 14.01 g/mol = 28.02 g/mol Number of moles of N2= Mass of N2 / Molar mass of N2 Number of moles of N2 = 1.4 g / 28.02 g/mol ≈ 0.05 mol Now, we can use the ideal gas law to find the volume (V) occupied by 0.05 moles of N2 at STP: V = nRT / P V = (0.05 mol) * (0.0821)* (273.15 K) / (1 atm) V ≈ 1.12 dm3

Q110. Metallic character of the elements:

• A. Decreases down the groups
• B. Increases down the groups✓
• C. Remains the same across the periods
• D. Increases across the periods

Explanation: The correct answer is that metallic character increases down the groups. This is because as we move down a group in the periodic table, the atomic size increases due to the addition of electron shells. As a result, the valence electrons are further from the nucleus and experience less effective nuclear charge, making them easier to lose and thus increasing metallic character.Option A is incorrect because metallic character increases, not decreases, down a group. Option C is incorrect because metallic character decreases as we move across a period from left to right, due to increased nuclear charge attracting electrons more strongly. Option D is incorrect because metallic character does not increase across a period for the same reason.

Q111. Molarity of pure water is:

• A. 1
• B. 18
• C. 36
• D. 55.5✓

Explanation: Molarity is defined as the number of moles of the solute per liter of solution. We know that the density of water is 1g/ml or 1 Kg/ L. Therefore, the mass of 1L of water is 1kg or 1000gm So now to find out the number of moles in the 1kg of water we can use the formula for mass to find out no. of moles in 1L(molarity). No.of moles=1000gm/18gm=55.56 mol 55.56 is thus the molarity of pure water.

Q112. The value of R (the gas constant) is

• A. 0.0821dm3 atm k mol-1.
• B. 803143 Nmk-Imole
• C. 0.0821 dm3 atm k-I mol-1✓
• D. 8.3143 dm3 atm-k-I mol

Explanation: The value of R in dm3atm k-1mol-1 is 0.0821.The table below provides values of R in different units.

Q113. Tritium, an isotope of hydrogen contains:

• A. Equal number of electrons and neutrons
• B. Equal number of electrons, protons and neutrons
• C. Number of neutrons is double than the number of protons✓
• D. Number of neutrons is half than the number of protons

Explanation: Tritium is the isotope of the hydrogen having mass number 3 and proton number 1.Number of neutrons are mass number-number protons which turn out to be 2. So we can say that the number of neutrons is twice the number of protons.

Q114. Which statement about the following equilibrium is correct?2SO2 (g) + O2(g) ⇌ 2SO3(g) ΔH= - 395 KJ/ mole

• A. The value of falls K, with rise in temperature✓
• B. The value of Kp falls with an increase in pressure
• C. The value of K is equal to Kp
• D. The value of K remains constant with rise in temperature.

Explanation: Kp equals the partial pressure of gases at the product side upon the partial pressure of gases at the reactant side. Increasing the temperature favors the reactant side as the backward reaction in this case is endothermic.The shift of equilibrium to reactant side causes the partial pressure of gases of reactant side to increase and pressure at product side to decrease. This in turn causes the value of Kp to fall.

Q115. The chemical name of K2[Zn(OH)4] is:

• A. Potassium tetrahydroxyzinc (II)
• B. Potassium tetrahydroxozincate (II)✓
• C. Potassium tetrahydroxyzincate (VI)
• D. Potassium hydroxyzinc (II)

Explanation: The chemical name of K2[Zn(OH)4] is derived by naming the cation first, which is Potassium. The complex ion is named by first identifying the central metal, Zinc, which has an oxidation state of +2, indicated in Roman numerals as (II). The presence of four hydroxide ions is denoted by 'tetrahydroxo'. Therefore, the correct name for the compound is Potassium tetrahydroxozincate (II), reflecting both the coordination number and the oxidation state of zinc. Other options are incorrect because they either misrepresent the oxidation state or the number of hydroxide ions in the compound.

Q116. When 3d orbital is complete, the next entering electron goes into:

• A. 4f
• B. 4s
• C. 4p✓
• D. 4d

Explanation: The correct order of electron orbital filling is determined by the Aufbau principle, which states that electrons fill orbitals starting from the lowest energy level to the highest. The sequence is: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, and so on. After the 3d orbitals are complete, the next electrons go into the 4p orbitals, making 4p the correct answer. Options 4f and 4d are filled much later in the sequence, and 4s is filled before 3d.

Q117. Which of the following pair groups belong to meta directing Groups?

• A. NH2 and -NO2
• B. -OR and -OH
• C. -NO2 and - SO3H✓
• D. CI and -COOH

Explanation: -NO2 and -SO3H are meta directing groups. The benzene ring has ortho positions(II and VI), para positions(IV), and meta positions(III and V). Those groups that are electrophile, also called meta-directing/deactivating groups, take electrons from the benzene ring towards themselves making the benzene to be deactivated. The benzene ring when deactivated directs the incoming groups to get attached to 3 and 5 positions which are meta positions.

Q118. What are the products of the below-mentioned equation?HNO3 +3HCI→

• A. 2H2O + NOCl + Cl2✓
• B. H2 + NOCl + 2HOCl
• C. H2O + NOCl + 2HCl
• D. 2H2O + NOCl + 2Cl

Explanation: The reaction of HNO3 with HCl in a 1:3 molar ratio forms aqua regia, generating water (H2O), nitrosyl chloride (NOCl), and chlorine gas (Cl2). This mixture is known for its capability to dissolve noble metals. The correct answer is Option A:2H2O + NOCl + Cl2. Options B, C, and D suggest incorrect products or incorrect stoichiometry of the reaction.

Q119. What is the order of the following reaction:2NO +O2 -> 2NO2

• A. 0
• B. 1
• C. 2
• D. 3✓

Explanation: The order of a chemical reaction is determined by the sum of the powers of the concentration terms in the rate law. For the reaction 2NO + O2 → 2NO2, the rate law is typically based on experimental data, but it can be inferred that the reaction is third-order: second-order with respect to NO and first-order with respect to O2. Therefore, the overall reaction order is 3. This is why Option D is correct, while Options A, B, and C do not accurately reflect the stoichiometry and concentration dependence of the given reaction.

Q120. One Calorie is equivalent to:

• A. 0.4184 J
• B. 41.84 J
• C. 4.184 J✓
• D. 418.4 J

Explanation: One calorie is defined as the amount of energy needed to raise the temperature of one gram of water by one degree Celsius. The correct conversion is 1 Calorie = 4.184 joules. Option A (0.4184 J) and Option B (41.84 J) are incorrect because they do not accurately represent the conversion rate. Option D (418.4 J) is incorrect as it overestimates the conversion factor. Understanding this conversion is essential when working with energy changes in thermochemical processes.

Q121. Paramagnetic elements contain:

• A. All paired electrons
• B. All unpaired electrons
• C. Few unpaired electrons.✓
• D. Unequal electrons and protons

Explanation: Paramagnetic elements are those with one or more unpaired electrons. These unpaired electrons create a net magnetic moment, making the element attracted to an external magnetic field. Option C is correct because it acknowledges the presence of unpaired electrons, which is the primary cause of paramagnetism. Option A is incorrect because paired electrons result in diamagnetism, not paramagnetism. Option B is misleading as it implies that all electrons must be unpaired for paramagnetism, which is not true. Even one unpaired electron can result in paramagnetism. Option D is unrelated to paramagnetism; it describes ions, which have an imbalance of electrons and protons, resulting in a charge.

Q122. How many atmospheres correspond to 1050 torr?

• A. 1.050
• B. 10.38
• C. 1.380✓
• D. 2.760

Explanation: In ancient times, the Torr was defined as a millimetre of Hg. So, as 1 atm = 760 mm Hg, therefore, 1 atm is also considered to be equal to 760 torrs. Now, we can calculate the atmospheres corresponding to 1050 torr, ∴ 1050 torr = 1050/760 atm = 1.38 atm

Q123. The mass of an electron is:

• A. 1.008 amu
• B. 1.009 amu
• C. 0.000550 amu✓
• D. 0.5500 amu

Explanation: The mass of an electron is approximately 0.000550 amu, which is much smaller compared to the masses of protons and neutrons (approximately 1 amu each). This small mass is due to the electron's relatively lower contribution to the overall mass of an atom. The incorrect options suggest masses closer to those of protons and neutrons, highlighting the importance of distinguishing between the masses of different subatomic particles.

Q124. The rate of E1 reaction depends upon:

• A. The concentration of the substrate✓
• B. The concentration of the nucleophile
• C. The concentration of both the nucleophile and the substrate
• D. The amount of the solvent used

Explanation: The E1 reaction, or unimolecular elimination reaction, involves two key steps: the formation of a carbocation intermediate from the substrate and the subsequent elimination of a leaving group. The rate-determining step is the formation of the carbocation, which depends only on the concentration of the substrate. Therefore, the rate of the E1 reaction is independent of the nucleophile concentration, distinguishing it from bimolecular reactions like SN2, which depend on both substrate and nucleophile concentrations. While solvents can influence the reaction conditions and stability of intermediates, they do not directly affect the rate of an E1 reaction.

Q125. The number of bonds in nitrogen molecules are:

• A. One sigma and one pi
• B. One sigma and two pi✓
• C. Three sigma only
• D. Two sigma and one pi

Explanation: The nitrogen molecule has three bonds in total that are 1 sigma and 2 pi.A single bond is always 1 sigmaA double bond is always 1 sigma and 1 piA triple bond is always 1 sigma and 2 pi.

Q126. An ionic compound A+ B- is most likely to be formed when:

• A. The ionization energy of A is high and the electron affinity of B is low.
• B. The ionization energy of A is low and the electron affinity of B is high.✓
• C. The ionization energy of A and the electron affinity of B is high.
• D. The ionization energy of A and the electron affinity of B is low.

Explanation: The correct answer is Option B: The ionization energy of A is low and the electron affinity of B is high. This is because a low ionization energy allows A to easily lose an electron and form a cation, while a high electron affinity allows B to easily gain an electron and form an anion, facilitating the formation of an ionic compound A+ B-.Option A is incorrect because a high ionization energy and low electron affinity would not favor the formation of ions. Option C is incorrect because while a high electron affinity is favorable for B, a high ionization energy is not favorable for A. Option D is incorrect because while a low ionization energy is favorable for A, a low electron affinity is not favorable for B.

Q127. The electrophile in aromatic sulfonation is:

• A. H2SO4
• B. HSO4
• C. SO3H+
• D. SO3✓

Explanation: In aromatic sulfonation, SO₃ acts as the electrophile that attacks the benzene ring to form the sulfonic acid. Concentrated H₂SO₄ helps generate and stabilize SO₃ but does not directly attack the ring.

Q128. Choose the correct IUPAC name for the following complex.[Cr(NH3)4Cl2]Cl

• A. Trichlorotetra amine chromium (III)
• B. Tetraamminedichlorochromium (III) chloride✓
• C. Dichloro Tetra ammonia chromium (III) chloride
• D. Dichlorotetra amine chromate (III) chloride

Explanation: The correct IUPAC name for the complex [Cr(NH3)4Cl2]Cl is Tetraamminedichlorochromium (III) chloride. The complex contains four ammine (NH3) ligands and two chloro (Cl) ligands, which are named in alphabetical order as 'tetraammine' and 'dichloro'. The oxidation state of the central metal ion, chromium, is +3, denoted as (III). The name ends with 'chloride' to indicate the presence of the counter ion Cl- outside the coordination sphere. Other options do not follow the IUPAC rules for naming coordination complexes, either by using incorrect prefixes, separating terms incorrectly, or misnaming the metal.

Q129. SN2 reactions can be best carried out with:

• A. Primary alkyl halides✓
• B. Secondary alkyl halides
• C. Tertiary alkyl halides
• D. Both primary and tertiary alkyl halides

Explanation: SN2 reactions involve a nucleophilic attack on the electrophilic carbon, leading to the inversion of configuration. The reaction is sensitive to steric hindrance around the electrophilic center. Therefore, primary alkyl halides are most suitable for SN2 reactions as they present the least steric congestion, allowing for efficient backside attack by the nucleophile. In contrast, secondary alkyl halides present moderate steric hindrance, making SN2 reactions possible but less favorable compared to primary halides. Tertiary alkyl halides are too sterically hindered for SN2 reactions and instead undergo SN1 reactions. Thus, primary alkyl halides are the best choice for SN2 reactions.

Q130. Name the main product formed as a result of the following reactionH3C - (CH2)5 - CH3 ————> Product n-heptaneConditions: 480 - 550 C, 150 - 399 psi V2O5

• A. Benzene
• B. Toluene✓
• C. Xylene
• D. Cyclohexane

Explanation: The above reaction leads to cyclization of n-heptane followed by the aromatization of that cyclic ring, this forms toluene, option B is correct. Benzene is the wrong option because benzene has six carbon while n-heptane has 7 carbon atoms. Cyclohexane is also the wrong option for the same reason. Xylene has 8 carbon atoms while our reactant has 7 carbon atoms.

Q131. The pH of 10-3 mol dm-3 of an aqueous solution H2SO4 is:

• A. 3.0
• B. 2.7✓
• C. 2.0
• D. 1.5

Explanation: H2SO4 is a strong acid that dissociates completely in water: H2SO4 ⇔ 2H+ + SO4-. Therefore, a 10-3 mol dm-3 solution of H2SO4 will produce 2 x 10-3 mol dm-3 of H+ ions. The pH is calculated as pH = -log10([H+]) = -log10(2 x 10-3) = 3 - log10(2). The value of log10(2) is approximately 0.301, so the pH = 3 - 0.301 = 2.699, which rounds to 2.7. Other options do not account correctly for the full dissociation and resultant concentration of hydrogen ions.

Q132. The oxidation state of Cl in HClO4 is:

• A. -1
• B. +5
• C. +7✓
• D. -7

Explanation: To determine the oxidation state of Cl in HClO4, you can use the known oxidation states of the other elements: hydrogen (H) is +1 and oxygen (O) is -2. Since HClO4 is a neutral compound, the sum of the oxidation states must be zero:+1 (for H) + Cl + 4(-2) (for O) = 0+1 + Cl - 8 = 0Cl - 7 = 0Cl = +7Therefore, the oxidation state of Cl in HClO4 is +7.Option A (-1) is incorrect as chlorine is not typically negative in oxyacids. Option B (+5) is incorrect as it's not the oxidation state of Cl in HClO4. Option D (-7) is incorrect as such a negative oxidation state is not typical for chlorine.

Q133. In a zero-order reaction, the rate is independent of:

• A. The temperature of the reaction
• B. The concentration of reactants✓
• C. The concentration of products
• D. The presence of a catalyst

Explanation: In a zero-order reaction, the rate of reaction is independent of the concentration of reactants. This means that even if the concentration of reactants changes, the rate remains constant. This is distinct from other reaction orders, where the rate depends on the concentration of one or more reactants. Temperature affects the rate of reaction as it influences kinetic energy and collision frequency. Catalysts accelerate the reaction rate by providing a lower-energy pathway, and product concentration can shift equilibrium but does not directly affect the rate of a zero-order reaction.

Q134. Which one of the following is NOT a nucleophile?

• A. H2S
• B. BF3✓
• C. NH3
• D. CN-

Explanation: A nucleophile is an electron-rich species capable of donating electron pairs to electron-deficient species. In contrast, electrophiles are electron-deficient and seek electrons. BF₃ is not a nucleophile because it is electron-deficient and acts as an electrophile, accepting electron pairs into its vacant orbital. H₂S, NH₃, and CN⁻ all have lone pairs of electrons that enable them to act as nucleophiles by donating electrons in reactions.

Q135. Which of the following molecules have zero dipole moments?

• A. NH3
• B. CHCl3
• C. H2O
• D. BF3✓

Explanation: The correct answer is BF3. BF3 is a trigonal planar molecule with symmetrical geometry, causing the dipole moments of the three B-F bonds to cancel each other out, resulting in a net dipole moment of zero. In contrast, NH3 has a trigonal pyramidal shape with a lone pair on nitrogen, resulting in a non-zero dipole moment. CHCl3 has a tetrahedral shape but lacks symmetrical distribution due to different atoms, which also results in a net dipole moment. H2O has a bent shape due to lone pairs, leading to a prominent dipole moment.

Q136. The ligand field effect splits five degenerate d-orbitals into two sets with different energies, the pair of high energy degenerate orbitals is:

• A. dxy, dyz
• B. dyz, dzx
• C. dx2-y2, dz2✓
• D. dx2, d

Explanation: In an octahedral crystal field, the five degenerate d-orbitals split into two distinct groups due to ligand interactions: the t2g set (dxy, dyz, dzx) with lower energy, and the eg set (dx2-y2, dz2) with higher energy. The eg orbitals align along the axes, directly facing the ligands, which results in significant repulsion and increased energy. Therefore, the correct answer is Option D. Options A and B are incorrect because they describe the t2g orbitals, which have lower energy. Option C is incorrect due to improper notation.

Q137. A catalyst increases the rate of reaction by:

• A. Increasing the reaction temperature.
• B. Increasing the concentration of reactants.
• C. Providing an alternative reaction pathway with a lower activation energy.✓
• D. Shifting the equilibrium towards the products.

Explanation: A catalyst speeds up a reaction without being consumed by providing a different mechanism or pathway for the reaction to follow. This alternative pathway has a lower activation energy, which allows a greater fraction of reactant molecules to react per unit of time.

Q138. Which of the following ions has the largest heat of hydration?

• A. Na+
• B. Al3+✓
• C. F-
• D. Sr2+

Explanation: The heat of hydration is determined by the charge density of the ion, which is the ratio of its charge to its size. Al3+ has the highest charge (+3) and a small ionic radius, maximizing its charge density. This results in very strong interactions with water molecules and the largest heat of hydration among the options. In contrast, Na+ and F- have lower charges, and Sr2+ has a larger size, all of which lead to lower charge densities and smaller heats of hydration compared to Al3+.

Q139. Determine the significant figures in 0.0085:

• A. 4
• B. 3
• C. 2✓
• D. 1

Explanation: The number 0.0085 contains two significant figures. According to the rules of significant figures:All non-zero digits are considered significant.Zeros that precede the first non-zero digit are not significant; they merely position the decimal point.In this number, 8 and 5 are the non-zero digits, thus there are 2 significant figures.Option A (4) and Option B (3) are incorrect because they miscount the zeros as significant. Option D (1) is incorrect because it undercounts the significant non-zero digits.

Q140. Write the chemical name of the given structure.

• A. 4-ethyl-2,5-hexadiyne
• B. 3-ethyl-1,4-hexadiene
• C. 3-ethyl-1,4-hexadiyne✓
• D. 3-ethyl-2,5-hexadiyne

Explanation: The correct name for the compound is 3-ethyl-1,4-hexadiyne. Following IUPAC naming conventions, the longest carbon chain is hexane, with an ethyl group on the 3rd carbon. The '1,4-diyne' indicates triple bonds between the 1st and 2nd, and 4th and 5th carbons. Option A starts numbering from the wrong end, Option B incorrectly identifies the bonds as double bonds, and Option D uses incorrect numbering and punctuation.

Q141. Copper (Cu, Z=29) is a

• A. d1 system with respect to the electronic configuration.
• B. d3 system with respect to the electronic configuration.
• C. d7 system with respect to the electronic configuration.
• D. d10 system with respect to the electronic configuration.✓

Explanation: Copper (Cu) is an exception in electronic configurations due to the stability provided by a fully filled d-orbital and a half-filled s-orbital. The correct configuration is 1s2, 2s2, 2p6, 3s2, 3p6, 4s1, 3d10. The presence of 10 electrons in the 3d orbital places copper in the d10 system. Options A, B, and C are incorrect because they suggest fewer electrons than present in the d-orbital.

Q142. The carbon number of gasoline is:

• A. C5 - C6
• B. C6 - C7
• C. C5 - C10✓
• D. C12 - C15

Explanation: Gasoline is a complex mixture of hydrocarbons, primarily composed of aliphatic hydrocarbons ranging from C5 to C10 carbon atoms. This range provides the necessary volatility and energy content for use as a fuel in internal combustion engines. Options A and B each only cover a subset of this range, while Option D describes a range typical of heavier fuels like kerosene, which are not suitable for gasoline engines due to their lower volatility.

Q143. The oxidation number of Br in Br2 is:

• A. -1
• B. -2
• C. 0✓
• D. +1

Explanation: The oxidation number of an atom in its elemental form is always zero. Since Br2 is in its elemental diatomic form, each bromine atom has an oxidation number of 0. Options -1, -2, and +1 represent oxidation states that bromine can have in various compounds, but not when it is in its elemental form.

Q144. The number of moles of CO2 which contain 8.0 g of oxygen is:

• A. 0.25✓
• B. 0.50
• C. 0.75
• D. 1.00

Explanation: To determine the number of moles of CO2, start by calculating the moles of O2. The molar mass of O2 is 32 g/mol. Therefore, 8 g of O2 is equal to 8/32 = 0.25 moles of O2. Each mole of CO2 contains exactly one mole of O2 (or two moles of oxygen atoms), meaning that 0.25 moles of O2 translates to 0.25 moles of CO2. The options 0.50, 0.75, and 1.00 are incorrect as they do not correctly apply stoichiometric principles between O2 and CO2.

Q145. Hydrogen bonds are represented by:

• A. dative bonds
• B. full bond
• C. partial charges
• D. dotted bonds✓

Explanation: Hydrogen bonds are represented as H···Y system, where the dots represent the hydrogen bond.

Q146. Effusion of gases take place through a hole with:

• A. Large hole dimensions
• B. Infinite dimensions
• C. Slit-like dimensions
• D. Molecular dimensions✓

Explanation: Effusion involves the movement of gas molecules through a tiny hole into a vacuum or another container. For effusion to occur, the hole must be small enough that gas molecules pass through it one at a time, which is why the correct option is 'Molecular dimensions.' Larger holes would allow more molecules to pass simultaneously, resembling diffusion. 'Infinite dimensions' imply no barrier, making effusion impossible, while 'Slit-like dimensions' would still permit multiple molecules to pass at once, not aligning with the concept of effusion.

Q147. For an equilibrium change involving gaseous phase, the forward reaction is first order while the reverse reaction is second order. The unit of Kp for the forward equilibrium is:

• A. atm✓
• B. atm2
• C. atm-1
• D. atm-2

Explanation: For a reaction where the forward reaction is first order and the reverse is second order, the equilibrium constant Kp for the forward reaction will have the unit of pressure raised to the power of the order of the forward reaction, which is atm. The units of Kp are derived from the partial pressures of the gases involved, and for a first-order reaction, the unit is simply atm. Other options such as atm2, atm-1, and atm-2 correspond to different reaction orders that do not match the given scenario.

Q148. In t-butyl alcohol, the tertiary carbon is bonded to:

• A. No H-atoms✓
• B. One H-atom
• C. Three H-atoms
• D. Four C-atoms

Explanation: In t-butyl alcohol, the tertiary carbon is bonded to three other carbon atoms and no hydrogen atoms. A tertiary carbon is defined by its connection to three carbons, which is characteristic of t-butyl alcohol. This is why Option A is correct. Option B is incorrect because there are no hydrogen atoms bonded to the tertiary carbon. Option C is incorrect because there are no hydrogen atoms attached to the tertiary carbon in t-butyl alcohol. Option D is incorrect because a carbon atom can have a maximum of four bonds, and in the case of t-butyl alcohol, it is bonded to three carbon atoms and the hydroxyl group.

Q149. The oxidation potential standard hydrogen electrode is arbitrarily taken as:

• A. -0.76 volts
• B. 0.00 volts✓
• C. +1.5 volts
• D. 1.0 volts

Explanation: The standard hydrogen electrode (SHE) is defined as having a potential of 0.00 volts under standard conditions (298 K, 1 atm, and solutions at 1 M concentration). This is because it serves as a universal reference point for measuring the electrode potentials of other half-cells. Other options such as -0.76 volts, +1.5 volts, and 1.0 volts are incorrect as they correspond to potentials of other electrodes or are arbitrary values not related to the SHE.

Q150. Down’s cell is used to prepare:

• A. Sodium carbonate
• B. Sodium bicarbonate
• C. Sodium hydroxide
• D. Sodium metal✓

Explanation: Down's cell is a method for obtaining sodium metal by the electrolysis of molten sodium chloride. In this process, graphite serves as the anode, releasing chlorine gas, while a steel cathode collects the molten sodium metal. Sodium carbonate, sodium bicarbonate, and sodium hydroxide are not products of this process. Sodium carbonate is produced using the Solvay process, sodium bicarbonate is derived from sodium carbonate, and sodium hydroxide is produced through the chlor-alkali process.

Q151. Which of the hydrogen compounds has the highest percentage of ionic character?

• A. HCl
• B. HBr
• C. HI
• D. HF✓

Explanation: The ionic character of a bond is largely determined by the difference in electronegativity between the two bonded atoms. Fluorine has the highest electronegativity of all elements, resulting in the largest electronegativity difference between hydrogen and fluorine in HF. This large difference gives HF the highest percentage of ionic character among the given hydrogen compounds. In contrast, HCl, HBr, and HI have progressively lower electronegativity differences and hence lower ionic character, with HI having the lowest due to iodine's relatively low electronegativity.

Q152. The solubility product of AgCl is 2.0x10-10 mol-2 dm-6. The maximum concentration of Ag+1 ions in the solution is:

• A. 2.0x10-12 mol dm-3
• B. 1.41x10-5 mol dm-3✓
• C. 1.0x10-12 mol dm-3
• D. 2.5x10-10 mol dm-3

Explanation: To find the maximum concentration of Ag+ ions in a solution of AgCl, we consider the dissolution process: AgCl(s) → Ag+(aq) + Cl-(aq). The solubility product expression is given by Ksp = [Ag+][Cl-]. Since the stoichiometry indicates that one mole of AgCl produces one mole of Ag+ and one mole of Cl-, we can denote their concentrations as [Ag+] = [Cl-] = s, where 's' represents solubility in mol dm-3. Thus, Ksp = s². Given Ksp = 2.0 x 10-10 mol2 dm-6, we can solve for 's': s² = 2.0 x 10-10, leading to s = √(2.0 x 10-10) ≈ 1.41 x 10-5 mol dm-3, which represents the maximum concentration of Ag+ ions.The other options are incorrect because they either stem from miscalculations or a misunderstanding of how to apply the Ksp expression and stoichiometry involved in the dissolution of AgCl.

Q153. A limiting reactant is the one, which:

• A. Is taken in a smaller quantity in grams as compared to the other reactant
• B. Is taken in a smaller quantity in volume as compared to the other reactant
• C. Limits the formation of the product by being consumed first✓
• D. Results in equal amounts of reactants and products

Explanation: The limiting reactant, or limiting reagent, is the reactant that is completely consumed first in a chemical reaction. This reactant determines the maximum amount of product that can be formed because once the limiting reactant is used up, the reaction cannot proceed further. Option C is correct because it accurately describes the role of the limiting reactant in limiting product formation. Options A and B are incorrect because the limiting reactant is not necessarily determined by a smaller mass or volume, but by stoichiometric relationships. Option D is incorrect because the limiting reactant does not result in equal amounts of reactants and products; it simply limits the amount of product based on its initial amount.

Q154. The chemical formula of Tincal is:

• A. Na2B2O7 . 10H2O
• B. Na2B4O7 . H2O
• C. Na2B4O7 . 10H2O✓
• D. Na2B2O5 . 10H2O

Explanation: The chemical formula of Tincal, also known as borax, is Na2B4O7 . 10H2O. This formula reflects the mineral's composition as a hydrated sodium borate, which includes four boron atoms, seven oxygen atoms, and ten water molecules.Option A is incorrect because it has the wrong boron to oxygen ratio, featuring only two boron atoms instead of four. Option B is incorrect because it lacks the complete hydration (10 water molecules) that characterizes Tincal. Option D is incorrect due to both an incorrect boron to oxygen ratio and an incorrect formula structure.

Q155. Hydrogen resembles the elements of groups:

• A. I-A, V-A and VIII-A
• B. I-A, IV-A and VI-A
• C. I-A, II-A and VII-A
• D. I-A, IV-A and VII-A✓

Explanation: Hydrogen is unique in its periodic behavior but shows similarities to several groups. It resembles group I-A because it has one valence electron and can lose this electron to form a cation. It resembles group IV-A because it can share electrons, akin to the group IV-A elements with half-filled valence shells. Additionally, it resembles group VII-A in its ability to gain an electron and form an anion, similar to the halogens. The other options incorrectly associate hydrogen with groups where it does not demonstrate such chemical similarities.

Q156. The unit cell parameters of the monoclinic system are:

• A. a=b≠c ; α=β=γ=90
• B. a≠b≠c ; α=γ=90 ; β≠90✓
• C. a≠b=c ; α=β=90; γ≠90
• D. a=b=c ; α=β=γ=90

Explanation: The monoclinic crystal system is characterized by three unequal axes, with two of them being perpendicular (α=γ=90°) and the third angle (β) differing from 90°. This distinguishes the monoclinic system from others where either all axes are equal or all angles are right angles. Option B correctly represents this with a≠b≠c ; α=γ=90° ; β≠90°. Options A, C, and D describe tetragonal, orthorhombic, and cubic systems, respectively, which do not fit the monoclinic parameters.

Q157. The colour of transition metal complexes is due to:

• A. d-d transitions of electrons✓
• B. Paramagnetic nature of transition elements
• C. Ionization
• D. Loss of s-electrons

Explanation: The color of transition metal complexes is primarily due to d-d transitions. In these complexes, the presence of a partially filled d subshell allows electrons to transition between different d orbitals. When light is absorbed, electrons are promoted to higher energy levels, and the specific wavelengths absorbed correspond to the color observed. This is why transition metals with no unpaired d electrons, such as Sc+3, Ti+4, V+5, Cu+1, and Zn+2, do not display the characteristic d-d transitions and are often colorless.Option B is incorrect because the paramagnetic nature of transition metals is related to unpaired electrons affecting magnetic properties rather than color. Option C is incorrect because ionization involves electron removal, not affecting the color directly. Option D is incorrect as the loss of s-electrons pertains to oxidation states rather than the origin of color in complexes.

Q158. Orbitals having the same energy are called:

• A. Hybrid orbitals
• B. Degenerate orbitals✓
• C. Valence orbitals
• D. Sub-orbitals

Explanation: Degenerate orbitals are orbitals within the same subshell that have equal energies. This is a key concept in quantum mechanics and atomic structure. These orbitals have the same energy when unaffected by external factors like electric or magnetic fields. Other options like hybrid orbitals, valence orbitals, and sub-orbitals describe different concepts:Hybrid orbitals: Result from the mixing of atomic orbitals for bonding purposes, not defined by energy equality.Valence orbitals: Located in the outer shell and involved in bonding, but not characterized by having the same energy.Sub-orbitals: Specific orbitals within subshells like s, p, d, and f, each with distinct quantum numbers, not necessarily sharing the same energy.

Q159. The oxidation state of Cl in HClO4 is:

• A. -1
• B. -5
• C. +7✓
• D. -7

Explanation: To determine the oxidation state of Cl in HClO4, we use the known oxidation states: +1 for hydrogen and -2 for oxygen. The equation is set up as:+1 (H) + Cl + 4(-2) (O) = 0.This simplifies to:+1 + Cl - 8 = 0.Solving for Cl gives Cl = +7. Therefore, the oxidation state of Cl is +7. The incorrect options result from miscalculations or misapplications of the oxidation state rules.

Q160. The pH of 10-3 M H2SO4 solution is:

• A. 3.0
• B. 2.7✓
• C. 2.0
• D. 1.5

Explanation: To determine the pH of a 10-3 M H2SO4 solution, recognize that H2SO4 is a strong acid that completely dissociates into 2 H+ and SO42-. Thus, the concentration of H+ ions is twice the initial concentration of H2SO4, which is 2 x 10-3 M. The pH is calculated using the formula: pH = -log[H+]. Substituting the concentration, we get pH = -log(2 x 10-3) = 3 - log(2) ≈ 2.7. Hence, the correct answer is 2.7. The other options result from incorrect calculations or misunderstandings of the relationship between H2SO4's dissociation and pH.

Q161. In the Compton Scattering experiment the X-ray wavelength change Δλ is _. Here h is Planck constant, m rest mass of electron and θ is angle after scattering.

• A. Δλ = h/m0c (1 + cosθ)
• B. Δλ = h/m0c (1 + cos2θ)
• C. Δλ = h/m0c (1 - cosθ)✓
• D. Δλ = h/m0c2 (1 + cosθ)

Explanation: The correct answer is Option C: Δλ = h/m0c (1 - cosθ). This formula represents the Compton scattering equation, where Δλ is the change in wavelength of the X-ray, h is Planck's constant, m is the rest mass of the electron, c is the speed of light, and θ is the scattering angle.Option A is incorrect because it incorrectly adds the cosine term instead of subtracting it. Option B is incorrect because it squares the cosine term, which is not part of the Compton formula. Option D is incorrect as it erroneously includes \( c^2 \) in the denominator, which does not belong in the equation.

Q162. An object is falling down with a speed of 20 m/s. After 3 secondsits velocity will be _ m/s (g = 10 m/s2).

• A. 05
• B. 50✓
• C. 55
• D. 95

Explanation: To find the final velocity of the object after 3 seconds of free fall, we use the kinematic equation: v = u + at. The initial velocity (u) is 20 m/s, the acceleration due to gravity (a) is 10 m/s2, and the time (t) is 3 seconds. Substituting these values into the equation, we get v = 20 + 10(3) = 20 + 30 = 50 m/s. Thus, the correct answer is 50 m/s. Option A (05) incorrectly assumes deceleration, Option C (55) miscalculates the velocity increase, and Option D (95) is an extreme overestimate.

Q163. In Young's double-slit experiment, if d is the separation between two slits, 𝝀 is the wavelength of light and θ is the angle of the line from the center of slits to the point of observation on the screen; then for maxima (bright fringe); the formula is _.

• A. 2d sinθ = mλ ; m = 0, 2, 4, ...
• B. dsinθ = mλ ; m = 0, 1, 2, ...✓
• C. sin θ = (m + ½) λ ; m = 0, 1, 2, ...
• D. 2msinθ = dλ ; m = 0, 1, 2, ...

Explanation: In Young's Double Slit Experiment, constructive interference (maxima) occurs when the path difference between light from the two slits is an integer multiple of the wavelength λ. This is given by the formula d sinθ = mλ where m is an integer (0, 1, 2, ...). This condition ensures that the light waves from the slits meet in phase, producing bright fringes on the screen.Option A is incorrect because it suggests maxima only occur for even values of m, which is not true. Option C is incorrect as it represents the condition for minima, where the path difference is a half-integer multiple of the wavelength, resulting in destructive interference. Option D is incorrect because the equation is incorrectly structured, misplacing the terms.

Q164. The polarization of light by tourmaline crystals is due to the _effect.

• A. Selective diffraction
• B. Selective reflection
• C. Selective interference
• D. Selective absorption✓

Explanation: The correct answer is selective absorption. Tourmaline crystals polarize light by absorbing one of the components of the light wave, allowing only the other component to pass through. This is because tourmaline is a dichroic material, meaning it has different absorption coefficients for different polarization directions of light. The other options are incorrect as they describe processes unrelated to the polarization of light by tourmaline: selective diffraction is about wave bending, selective reflection is about surface reflections, and selective interference is about wave superposition.

Q165. A paratrooper is falling down with uniform velocity and also rotating with a constant angular velocity of 0.2 rad/sec. The body satisfies _.

• A. The first condition of equilibrium but not the second
• B. The second condition of equilibrium but not the first
• C. Both the first and second conditions of equilibrium✓
• D. Neither the first nor the second condition of equilibrium

Explanation: The correct answer is Option C: Both the first and second conditions of equilibrium. The first condition of equilibrium states that the sum of all forces acting on an object must be zero for it to move with constant velocity; since the paratrooper is falling with uniform velocity, this condition is met. The second condition of equilibrium states that the sum of all torques acting on an object must also be zero for it to rotate with constant angular velocity; since the paratrooper is rotating with a constant angular velocity of 0.2 rad/sec, this condition is also satisfied. Options A and B are incorrect as they each claim that only one condition of equilibrium is satisfied while in fact, both are. Option D is also incorrect because it suggests that neither condition is satisfied, which contradicts the provided information about uniform velocity and constant angular velocity.

Q166. If 92 U 235, decays by emitting two α one β and two γ -rays the new daughter element is = _.

• A. 88 Y 227
• B. 89 Y 227✓
• C. 90 Y 227
• D. 89 Y 231

Explanation: When 92U235 undergoes two alpha decays, it loses 4 protons and 8 neutrons, reducing the atomic number to 88 and the mass number to 227. The emission of a beta particle converts a neutron to a proton, increasing the atomic number by 1 to 89 without affecting the mass number. Gamma rays have no effect on the atomic or mass numbers as they are energy emissions without mass or charge. Thus, the resulting daughter element is 89Y227.Option A is incorrect as it miscalculates the decay process. Option C assumes no beta decay effect. Option D incorrectly calculates the mass number post-decay.

Q167. A changing current in a coil sets up a changing magnetic field around it which in turn induces an e.m.f. in it. This effect is known as _

• A. Simple induction
• B. Mutual induction
• C. Self-induction✓
• D. EMF induction

Explanation: The correct answer is self-induction. This is because a changing current in a coil leads to a changing magnetic field, which induces an emf within the same coil. This specific phenomenon is known as self-induction.Option A, 'Simple induction', is not a recognized term in electromagnetism for this process. Option B, 'Mutual induction', involves two different coils, where a change in current in one induces emf in the other, which is not the case here. Option D, 'EMF induction', is a generic term and does not specify the process as accurately as 'self-induction'.

Q168. The principle of an AC generator is.

• A. Lenz's Law
• B. Faraday's Law✓
• C. Self-Induction
• D. Ampere's Law

Explanation: The correct answer is Faraday's Law. AC generators operate on the principle of electromagnetic induction, where an emf is induced in a coil as it rotates in a magnetic field, causing a change in the magnetic flux through the coil. This principle is succinctly described by Faraday's Law, which states that the induced emf in a circuit is proportional to the rate of change of magnetic flux through the circuit.Lenz's Law, while related to electromagnetic induction, describes the direction of the induced emf and current. Self-induction refers to emf induced by a change in current in the same coil, not by external magnetic fields. Ampere's Law deals with the relationship between current and magnetic fields in closed loops, which is not directly applicable to the operation of generators.

Q169. Bragg's Law for measurement of wavelength à. of i-rays, using crystal lattice planes having distance d between each other, for constructive interference for integral multiple of i is.

• A. mλ = 2d/ sinθ
• B. 2λ =md sinθ
• C. mλ = 2d sinθ✓
• D. dλ = 2m sinθ

Explanation: nλ=2d⋅sin⁡θ where • n is an integer determined by the order given, • λ is the wavelength of x-rays, and moving electrons, protons, and neutrons, • d is the spacing between the planes in the atomic lattice, and • θ is the angle between the incident ray and the scattering planes.

Q170. The velocity of a particle is related to time according to the equation V= ct3. The dimensions of constant:

• A. L-1T-1
• B. LT-3
• C. LT -4✓
• D. L-2T-2

Explanation: To determine the dimensions of the constant c in the equation V = ct3, we use the principle of dimensional homogeneity. The velocity V has dimensions LT-1, while time t has dimensions T. Rearranging the equation gives us:(LT-1) = c(T3)Solving for c, we divide both sides by T3, resulting in:c = (LT-1)/(T3) = LT-4.This confirms that the correct dimensions for c are LT-4. The other options do not match this dimensional requirement, thus they are incorrect.

Q171. What should the distance of an object from a convex lens of focal length f=10 cm to produce an erect image twice as large as the object?

• A. 20 cm from the lens
• B. 15 cm from the lens
• C. 10 cm from the lens
• D. 5 cm from the lens✓

Explanation: To solve this problem, we use the lens formula: \( \frac{1}{f} = \frac{1}{v} - \frac{1}{u} \) where \( f \) is the focal length, \( v \) is the image distance, and \( u \) is the object distance.Since the image is erect and twice the size of the object, the magnification \( m = \frac{v}{u} = 2 \). For a convex lens, an erect image is virtual and on the same side as the object, indicating \( v = -2u \).Substituting into the lens formula: \( \frac{1}{10} = \frac{1}{-2u} - \frac{1}{u} \) Simplifying, \( \frac{1}{10} = -\frac{1}{2u} + \frac{1}{u} \) \( \frac{1}{10} = \frac{1}{2u} \) \( 2u = 10 \) \( u = 5 \) cm.Thus, the correct object distance is 5 cm. The other options do not satisfy the conditions for forming an erect image with the given magnification.

Q172. Lungs do not collapse between breaths and some air always remains in the lungs which can never be expelled because:

• A. There is a negative pressure in the lungs
• B. There is a negative intarpleural pressure pulling at the lung walls✓
• C. There is a positive intrapleural pressure
• D. Pressure in the lungs is higher than the atmospheric pressure.

Explanation: Negative intrapleural pressure helps keep the lungs expanded even after forceful expiration.

Q173. The scalar or Dot product of Vectors (3i - 2j + 4k) and (2i + 2j - 3k) is _.

• A. -9
• B. -10✓
• C. -11
• D. 10

Explanation: (3)(2)+(-2)(2)+(4)(-3) 6-4-12 =-10

Q174. The sum of Kinetic energy and the Potential energy is always constant provided that _ .

• A. There is a greater force of friction involved during motion
• B. The body is in simple harmonic motion without any external forces like friction✓
• C. There is less force of friction involved during motion
• D. No force of friction involved during motion

Explanation: The correct answer is that the sum of kinetic energy and potential energy is always constant when the body is in simple harmonic motion without any external forces like friction. In an ideal simple harmonic oscillator, energy is conserved because there are no energy losses due to friction or other non-conservative forces. This means that at any point in time, the total mechanical energy, which is the sum of kinetic energy and potential energy, remains the same.Options A and C are incorrect because any presence of friction, whether greater or lesser, results in the conversion of mechanical energy into other forms such as heat, thus reducing the total mechanical energy over time. Option D, although true in ideal scenarios, lacks the specificity of being in simple harmonic motion, which is necessary to define the system where energy conservation is observed.

Q175. Three times decrease in the distance between the plates of a parallel plate, capacitor will _.

• A. Decrease the capacitance three times
• B. Decrease the capacitance nine times
• C. Increase the capacitance three times✓
• D. Increase the capacitance six times

Explanation: Capacitance of a parallel plate capacitor is given by the formula C = ε₀(A/d), where C is the capacitance, ε₀ is the permittivity of free space, A is the area of the plates, and d is the distance between the plates. When the distance d is decreased to one-third, the capacitance C increases by a factor of three. Therefore, a three times decrease in the distance results in a threefold increase in capacitance. Other options are incorrect as they either misinterpret or miscalculate the relationship between capacitance and distance.

Q176. A car of mass 1200 kg initially at rest has been accelerated to a speed of 8 m/s in 16 meters. Average acceleration of the car is _ m/s2? And force is _ N?

• A. 1.5 and 1500
• B. 2.5 and 2400
• C. 3.5 and 3500
• D. 2 and 2400✓

Explanation: To solve this problem, we start by determining the acceleration using the kinematic equation v² = u² + 2as, where:v is the final velocity (8 m/s),u is the initial velocity (0 m/s, since the car starts from rest),a is the acceleration, ands is the displacement (16 m).Substituting the known values into the equation:(8)² = (0)² + 2(a)(16)64 = 32aa = 2 m/s²Next, apply Newton's second law to find the force: F = ma.F = 1200 kg × 2 m/s² = 2400 NTherefore, the correct values are an acceleration of 2 m/s² and a force of 2400 N. The other options are incorrect because they do not satisfy both the acceleration and force calculations based on the given conditions.

Q177. In the SI system of units, the fundamental units of length, mass, and time are _, _ and _ respectively:

• A. Meter, Kilogram, and Kilo second
• B. Kilometre, Kilogram, and Hour
• C. Meter, Kilogram, and Second✓
• D. Centimetre, Centigram, and Second

Explanation: The correct answer is Option C: Meter, Kilogram, and Second.Meter (m) is the base unit of length in the SI system, defined by the distance light travels in a vacuum in 1/299,792,458 of a second.Kilogram (kg) is the base unit of mass, defined based on a fixed numerical value of the Planck constant.Second (s) is the base unit of time, defined as the duration of 9,192,631,770 periods of the radiation corresponding to the cesium-133 atom's transition.Other options are incorrect because they either use derived units or units not recognized as the base SI units for length, mass, or time.

Q178. In Nuclear Physics the mass defect is referred to _.

• A. The difference in masses of free neutrons and protons.
• B. The difference in masses of free neutrons and bonded nucleus
• C. The difference in masses of free nuclear constituents and bonded nucleus✓
• D. Difference between atomic mass and atomic number

Explanation: The correct answer is Option C. The mass defect refers to the difference between the total mass of individual nucleons (protons and neutrons) when they are free and the mass of the nucleus they form when bound together. This difference arises because some mass is converted to energy and released when the nucleus is formed, according to Einstein's equation E=mc².Option A is incorrect because it only considers neutrons and protons individually, not the entire nuclear mass. Option B is incorrect as it only considers neutrons and not the entire set of nucleons. Option D is incorrect because it confuses the mass defect with the difference between atomic mass and atomic number, which relates to the number of protons and neutrons in an atom.

Q179. The formula for the Paschen series for the Hydrogen spectrum is _.

• A. 1/λ=Rh(1/22 - 1/n2); n=3,4,5
• B. 1/λ=Rh(1/42 - 1/n2); n=2,3,4,5
• C. 1/λ=Rh(1/42 - 1/n2); n=5,6,7
• D. 1/λ=Rh(1/32 - 1/n2); n=4,5,6✓

Explanation: The correct formula for the Paschen series is Option D: 1/λ=Rh(1/32 - 1/n2); n=4,5,6. The Paschen series refers to electron transitions ending at the n=3 energy level, resulting in spectral lines in the infrared region. The other options represent different series or incorrect configurations: Option A represents the Balmer series, transitioning to n=2. Option B does not correspond to any recognised series due to its incorrect configuration. Option C represents the Brackett series, transitioning to n=4.

Q180. The necessary condition for Boyle's law to hold is that the process must be _.

• A. Isobaric
• B. Adiabatic
• C. Isochoric
• D. Isothermal✓

Explanation: Boyle's law states that the pressure of a gas is inversely proportional to its volume when the temperature is kept constant. This is why the process must be isothermal for Boyle's law to hold. In contrast, an isobaric process keeps pressure constant, an adiabatic process involves no heat transfer, and an isochoric process maintains constant volume, none of which satisfy the conditions of Boyle's law.

Q181. A body is hanging from a rigid support by an extensible string of length L. It is struck inelastically by an identical body of mass m with horizontal velocity v =√2gl , the tension in the string increases just after striking by:

• A. mg
• B. 3mg
• C. 2mg✓
• D. None of these

Explanation: Initially, the tension in the string is T = mg, which equals the weight of the hanging body. When struck by an identical body inelastically, the system's mass becomes 2m. Conservation of momentum gives us:mv = 2m(v'), thus v' = v/2.Using the inelastic collision principles, the new tension T' is given by T' - 2mg = 2m(v')^2/L. By substituting v' = v/2 and v = √(2gL), we find T' = 3mg.Therefore, the tension increase is T' - T = 3mg - mg = 2mg.Option A is incorrect as it ignores the momentum change. Option B miscalculates the velocity and resultant tension. Option D is incorrect since the calculated increase in tension is indeed 2mg, making Option C the right choice.

Q182. When an object is thrown upward, it rises to height h. How high is the object in terms of h, when it has lost ⅓ of its original kinetic energy?:

• A. H/2
• B. H/3✓
• C. H/4
• D. H/6

Explanation: When an object is thrown upward, its initial kinetic energy is gradually converted into potential energy as it rises. According to the conservation of energy, the loss in kinetic energy should equal the gain in potential energy.If the object has lost 1/3 of its original kinetic energy, this energy has been transformed into potential energy. Therefore, the object has gained potential energy equivalent to 1/3 of its original kinetic energy, which corresponds to a rise to 1/3 of its maximum height, H.Thus, the object is at a height of H/3 when it has lost 1/3 of its original kinetic energy. The other options are incorrect because they represent different fractions of energy conversion.

Q183. The internal energy of the system decreases in an adiabatic process. Which of the following must be true regarding this process?

• A. Heat flows out of the system
• B. Work is done by the system✓
• C. Work is done by the surroundings
• D. The potential energy of the system is changing

Explanation: According to the first law of thermodynamics, Q = ΔU + W, where Q is the heat added to the system, ΔU is the change in internal energy, and W is the work done by the system. In an adiabatic process, Q = 0, so the equation simplifies to ΔU = -W. This means that if the internal energy decreases, W must be positive, indicating that work is done by the system on the surroundings. Thus, the correct answer is that work is done by the system. The other options are incorrect because they either suggest heat transfer (which does not occur in an adiabatic process) or involve potential energy, which is not directly related to the described process.

Q184. If μ is the permeability of the medium and ∈ permittivity of the medium then the value of √ 1 / μ . ∈. Is equal to _.

• A. Planck's constant
• B. Speed of sound waves
• C. Speed of ultrasound waves
• D. Speed of light✓

Explanation: The correct answer is the speed of light. The relationship between permeability (μ) and permittivity (∈) of a medium is fundamental in determining the speed of light (c) in that medium. Specifically, the speed of light is given by the equation c = √(1/μ∈). This is because the speed of light in a vacuum is defined by these electromagnetic properties. In contrast, Planck's constant is a quantum mechanical constant, while the speed of sound and ultrasound waves depend on the medium's mechanical properties rather than its electromagnetic ones.

Q185. Which statement describes the electric potential difference between two points in the electric field of charge Q?

• A. The difference in electric field strength between two points per unit charge.
• B. The ratio of the power dissipated between the points to the mass of the charge
• C. The work done in moving a test charge between points divided by the magnitude of the test charge.✓
• D. The force required to move a unit positive charge between the points per unit charge.

Explanation: The correct definition of electric potential difference is the work done in moving a test charge between two points divided by the magnitude of the test charge. This is because electric potential difference is a measure of the energy per unit charge required to move a charge within an electric field. Option A is incorrect as it confuses electric field strength with potential difference. Option B is irrelevant to the concept of potential difference, as it incorrectly involves power and mass. Option D mistakenly relates force to potential difference, whereas potential difference is concerned with energy (or work) per unit charge.

Q186. In a step up transformer _.

• A. Vs > Vp while Is > Ip
• B. Vs < Vp while Is > Ip
• C. Vs = Vp while Is > Ip
• D. Vs > Vp while Is < Ip✓

Explanation: A step-up transformer increases the secondary voltage (Vs) compared to the primary voltage (Vp) while decreasing the secondary current (Is) compared to the primary current (Ip). This is consistent with the conservation of energy, where the power (P = V × I) remains constant (minus losses). Therefore, as voltage increases, current must decrease. Option A is incorrect because both voltage and current cannot increase simultaneously due to conservation of energy. Option B is incorrect as it describes a step-down transformer. Option C is incorrect because it suggests no voltage change, which does not apply to step-up transformers.

Q187. If a compressible medium has bulk modulus denoted by B and density denoted by P, then a Newton's formula for the speed of sound in a medium is _.

• A. V = √(B / P)✓
• B. V = √(B * P)
• C. V = B / P
• D. V = √(P / B)

Explanation: The speed of sound in a compressible medium is given by Newton's formula: V = √(B / P), where B is the bulk modulus and P is the density of the medium. The formula shows that the speed of sound is directly proportional to the square root of the ratio of the bulk modulus to the density. This is because a higher bulk modulus (indicating a stiffer medium) and a lower density both contribute to a higher speed of sound.Option A is correct because it correctly reflects this relationship. Option B is incorrect as it suggests multiplying the bulk modulus by the density, which does not describe the speed of sound. Option C is incorrect because it lacks the square root, which is necessary for the correct calculation. Option D is incorrect as it reverses the roles of bulk modulus and density.

Q188. In order to produce pair production the minimum energy of photon required is:

• A. 1.02 KeV
• B. 1.02 MeV✓
• C. 10.2 KeV
• D. 1.00 MeV

Explanation: Pair production is a process where a photon is converted into an electron-positron pair. For this to occur, the photon must have a minimum energy equal to twice the rest mass energy of an electron, which is approximately 1.02 MeV. This is because the rest mass energy of an electron (or positron) is about 0.511 MeV, and two such particles are created. Therefore, 1.02 MeV is the minimum necessary energy for pair production. The options 1.02 KeV and 10.2 KeV are far too low, as they are measured in KeV (kilo-electron volts) rather than MeV (mega-electron volts). Option 1.00 MeV is close but does not meet the required threshold.

Q189. The Bohr’s postulate for stationary orbits of Hydrogen atoms _. Here m is the mass of the electron, v velocity, r orbital, and h is Planck's constant.

• A. mr=nhv/2ℼ
• B. mvr=nh/2ℼ✓
• C. mvr=nh/2ℼr
• D. mv=nhr/2ℼ

Explanation: Bohr's postulate regarding stationary orbits states that the angular momentum (L) of an electron is quantized and can be expressed as L = mvr = nh/2π, where n is a positive integer. This means that the electron can only occupy certain orbits where its angular momentum is an integral multiple of h/2π.The correct option, Option B, accurately represents this quantization with mvr = nh/2π.Option A, C, and D incorrectly represent the formula with additional terms or incorrect arrangements, not aligning with the quantization condition as described by Bohr.

Q190. A car starts from rest and moves with constant acceleration. During the 4th second of its motion, it covers a distance of 21 meters. The acceleration of the car is _ m.

• A. 04
• B. 06✓
• C. 08
• D. 16

Explanation: To determine the acceleration, utilize the formula for distance covered in the nth second of uniformly accelerated motion:Sn = u + ½ a (2n-1)Given:u = initial velocity = 0 m/s (as the car starts from rest)a = acceleration (unknown)n = 4 (since we are considering the 4th second)Sn = 21 metersSubstitute these values into the equation:21 = 0 + ½ × a × (2×4 - 1)21 = ½ × a × 742 = 7aTherefore, a = 6 m/s².The other options are incorrect due to errors in either substituting values into the formula or performing the calculations.

Q191. Which particle (marked A) is obtained in the following nuclear reaction?4Be9 + 2He4 -> 6C12 + A

• A. A = 1H1
• B. A = 0n1✓
• C. A = 1H2
• D. A = 2He2

Explanation: To determine the missing particle in the nuclear reaction, compare the mass numbers and atomic numbers on both sides of the equation. Initially, 4Be9 and 2He4 combine to form 6C12 and another particle. The total mass number on the reactant side is 13 (9 + 4), and the atomic number is 6 (4 + 2). On the product side, 6C12 contributes a mass number of 12 and an atomic number of 6, leaving a discrepancy of 1 in mass number to be accounted for by the particle A. The correct balance is achieved by a neutron, 0n1, which has a mass number of 1 and no charge, thereby satisfying both the mass and atomic number requirements. Other options, such as hydrogen-1, deuterium, or helium-2, do not satisfy these conditions.

Q192. An electron moving with velocity v has momentum 3 x 10 -26 Kg.m/s. The de Broglie wavelength associated with it is _. Value of h = 6.63 x 10-34 is.

• A. 24.1 nm
• B. 22.14 m
• C. 22.1 nm✓
• D. 22.1 mm

Explanation: The de Broglie wavelength formula is λ = h/p, where h is Planck's constant and p is the momentum of the electron. Given the momentum p = 3 × 10-26 Kg.m/s and h = 6.63 × 10-34 J.s, substitute these values into the formula to find λ:λ = 6.63 × 10-34 / 3 × 10-26 = 22.1 nm.Option A is incorrect due to a calculation error. Option B is incorrect because it suggests a much larger and incorrect unit (meters). Option D is incorrect due to the wrong unit (millimeters). Thus, Option C is the correct answer with the correct units and calculation.

Q193. Laplace's correction to Newton’s formula is based on the fact that the compressions and rarefactions occur as _.

• A. Adiabatic process✓
• B. Isothermal process
• C. Isochoric process
• D. Isobaric process

Explanation: Laplace's correction to Newton’s formula recognizes that sound waves involve rapid compressions and rarefactions where there is insufficient time for heat exchange with surroundings, making the process adiabatic. Newton's original assumption of an isothermal process (constant temperature) was incorrect because it fails to consider the rapid temperature changes accompanying pressure variations in sound waves.The adiabatic process assumption accounts for these temperature changes, leading to a more accurate formula for sound speed in gases. The other processes—isochoric (constant volume) and isobaric (constant pressure)—do not describe the conditions experienced during sound wave propagation.

Q194. A car 500 kg is travelling at a constant speed of 9 m/s round a curve of 100m. What is the centripetal force?

• A. 205N
• B. 305N
• C. 405N✓
• D. 505N

Explanation: The formula for centripetal force is Fc = mv²/r, where:m is the mass of the car (500 kg)v is the speed of the car (9 m/s)r is the radius of the curve (100 m)Plugging in these values, we calculate:Fc = (500 kg * (9 m/s)²) / 100 mFc = (500 kg * 81 m²/s²) / 100 mFc = 40500 kg⋅m/s² / 100 mFc = 405 NThis confirms that the correct answer is 405N. Other options are incorrect due to errors in calculation or incorrect application of the formula.

Q195. When a train whistling passes near you, a considerable change in the pitch of the sound is heard. When the train is moving away, the pitch of the sound _ whereas the pitch of the sound _ when the train is approaching.

• A. Increases … decreases
• B. Increases … remains same
• C. Decreases … increases✓
• D. Decreases … remains same

Explanation: The correct answer is that the pitch of the sound decreases when the train is moving away and increases when the train is approaching. This phenomenon is explained by the Doppler effect, which describes how the frequency of a wave changes relative to an observer moving in relation to the source of the wave. When the train approaches, the sound waves are compressed, resulting in a higher frequency and thus a higher pitch. Conversely, when the train moves away, the sound waves are stretched out, leading to a lower frequency and lower pitch. The other options misunderstand this effect, suggesting incorrect changes in pitch or that the pitch remains unchanged, which is not consistent with the principles of wave motion and the Doppler effect.

Q196. The vector product of two vectors A and B is _ vectors A and B.

• A. Not equal to the product of magnitudes of
• B. In the plane parallel to
• C. Perpendicular to the plane containing✓
• D. Less in magnitude than the product of magnitudes of

Explanation: The vector product, or cross product, of two vectors A and B results in a vector perpendicular to the plane containing A and B. This is determined using the right-hand rule, which helps visualize the direction of the resulting vector. The magnitude of the cross product is |A × B| = |A||B|sin(θ), where θ is the angle between A and B. Option C correctly identifies the perpendicular nature of the resulting vector. Option A is incorrect because it misrepresents the nature of the cross product as a scalar. Option B is incorrect because it misinterprets the orientation as parallel rather than perpendicular. Option D is incorrect because it inaccurately describes the magnitude relationship without considering the sine component.

Q197. If a conductor carrying current I is placed in uniform magnetic field B, It experiences a magnetic force F. The direction of this force F.

• A. Is parallel to current I only
• B. Is perpendicular to current I only
• C. Is perpendicular to magnetic field B only
• D. Is perpendicular to both current I and magnetic field B✓

Explanation: The correct answer is that the force is perpendicular to both the current I and the magnetic field B. This is determined using the right-hand rule, where the thumb represents the direction of the current, the fingers represent the direction of the magnetic field, and the palm faces the direction of the force.The other options are incorrect because they fail to recognize the dual perpendicular nature of the force direction concerning both the current and the magnetic field.

Q198. If loop of Henle were absent from mammalian nephron which one of the following is to be expected?

• A. There will be no urine formation.
• B. There will be hardly any change in the quality and quantity of urine formed
• C. The urine will be more concentrated
• D. The urine will be more dilute✓

Explanation: Reabsorption is a process by which useful constituents of glomerular filtrate are returned into the blood streams. It occurs in convoluted tubules (proximal convoluted tubule) as well as loop of Henle. Basically loop of Henle, in association with vasa rectae, plays an important role in the counter current mechanism (the process which makes urine hypertonic, i.e., more concentrated).Therefore, if Henle’s loop was absent from mammalian nephron the urine will be more dilute.

Q199. If the time interval between the occurrence of two events is measured in a frame with no relative motion in which two events occur. Then the time measured by the observer in a frame moving with relative velocity v is _.

• A. t = t0 * √(1-v²/c²)
• B. t = t0 / √(1-v²/c²)✓
• C. t = t0 * (1-v²/c²)^{3/2}
• D. t = t0 / (1-v²/c²)

Explanation: The correct answer is Option B: t = t0 / √(1-v²/c²). This formula arises from the theory of special relativity and describes time dilation, which states that time measured in a moving frame appears to be longer compared to a stationary frame. The Lorentz factor, √(1-v²/c²), accounts for the effects of relative motion on the perception of time. The other options incorrectly apply or modify this factor, resulting in incorrect calculations of time dilation.

Q200. A travelling wave, in which the particles of the distributed medium, move parallel to the direction of propagation of the wave is called:

• A. Transverse wave
• B. Circular wave
• C. Longitudinal wave✓
• D. Stationary wave

Explanation: Longitudinal waves are characterized by particle motion that is parallel to the direction of wave propagation. This creates alternating regions of compression and rarefaction. Sound waves in air are a classic example, where air particles oscillate back and forth in the same direction as the wave is moving.Transverse waves, on the other hand, involve particle movement perpendicular to wave direction, as seen in waves on strings or electromagnetic waves. Circular waves are typically seen on water surfaces, where the motion is vertical and not parallel. Stationary waves involve a pattern of nodes and antinodes due to interference, with particles oscillating in place.