Sindh Mdcat 2025 — Solved Past Paper with Answers

Q1. He said, “Will you listen to such a man?” Choose the most appropriate indirect speech:

• A. He asked them that they would listen to such a man.
• B. He asked them whether they would listen to such a man.✓
• C. He told them whether they will listen to such a man.
• D. He asked them to listen to such a man.

Explanation: The correct answer is Option B: 'He asked them whether they would listen to such a man.' This option accurately reflects the structure of indirect speech by using 'whether' to introduce the question and changes the tense from 'will' to 'would,' which is necessary for indirect questions. The other options are incorrect for various reasons: Option A adds 'that,' which is unnecessary, and keeps the tense unchanged; Option C fails to change 'will' to 'would'; and Option D alters the meaning by turning the question into a command.

Q2. “His lachrymose speech at the funeral moved everyone to tears.” Choose the synonym forlachrymose:

• A. Joyful
• B. Weepy✓
• C. Monotonous
• D. Humorous

Explanation: The correct answer is 'weepy', which is a synonym for 'lachrymose', describing a state of being tearful or sorrowful. In the context of the sentence, the speech was emotional enough to bring people to tears, aligning perfectly with the meaning of 'lachrymose'.The other options are incorrect as follows: 'joyful' is the opposite of the intended emotional tone, 'monotonous' suggests a dullness that does not capture the emotional depth, and 'humorous' indicates a light-heartedness that contradicts the sadness implied in the context of a funeral.

Q3. . Identify the simile:

• A. She trembled like a leaf in the wind.✓
• B. She was a statue, frozen in fear.
• C. She was drowning in doubt.
• D. Her thoughts were a whirlwind.

Explanation: The correct answer is Option A: She trembled like a leaf in the wind. because it clearly uses 'like' to create a simile, drawing a comparison between the woman's trembling and a leaf's movement. The other options (B, C, and D) are metaphors; they do not use 'like' or 'as' to make a comparison, but rather state that one thing is another, which distinguishes them from similes.

Q4. The board will approve the budget only after the auditor verifies the accounts. The mostappropriate passive voice is:

• A. The budget will be approved by the board only after the accounts are verified by theauditor.✓
• B. The budget is approved by the board only after the accounts have been verified by theauditor.
• C. The budget is being approved by the board only after the accounts are verified by the auditor.
• D. The budget has been approved by the board only after the accounts were verified by theauditor.

Explanation: The correct answer is Option A: 'The budget will be approved by the board only after the accounts are verified by theauditor.' because it accurately conveys the future passive voice, where the action of approving the budget is performed by the board, emphasizing that the budget will only be approved after the accounts are verified. The use of 'will be approved' indicates a future event, perfectly aligning with the original statement's time frame. Options B, C, and D are incorrect because they either misrepresent the tense or imply that the approval has already happened, which does not match the original context.

Q5. He does his work without any care. The underlined part of the sentence is:

• A. Adverb phrase✓
• B. Adjective phrase
• C. Noun phrase
• D. Appositive phrase

Explanation: The correct answer is an adverb phrase because it describes the manner in which the action of the verb 'does' is performed. The phrase 'without any care' indicates how he does his work, thereby modifying the verb. The other options are incorrect because they refer to types of phrases that either modify nouns (adjective and appositive phrases) or serve as the subject/object (noun phrases), which is not the function of 'without any care' in this sentence.

Q6. The purpose of using exaggerated language in parody is:

• A. To create a serious tone
• B. To criticize societal norms
• C. To entertain and mock✓
• D. To confuse the reader

Explanation: The correct answer is Option C: To entertain and mock. Exaggerated language is a hallmark of parody, as it effectively amplifies certain characteristics or behaviors to evoke laughter and highlight absurdity. Options A and D misinterpret the function of exaggerated language, as they suggest outcomes that do not align with the comedic and critical nature of parody. Option B, while somewhat related, does not directly address the primary purpose of using exaggerated language, which is fundamentally about entertainment and mockery.

Q7. Choose the correct sentence:

• A. The new policy aims at reduce waste, to promote recycling, and creating awareness among citizens.
• B. The new policy aims to reducing waste, promoting recycling, and create awareness among citizens.
• C. The new policy aims to reduce waste, to promote recycling, and creating awareness among citizens.
• D. The new policy aims to reduce waste, promote recycling, and create awareness among citizens.✓

Explanation: The correct answer is Option D: 'The new policy aims to reduce waste, promote recycling, and create awareness among citizens.'. This option correctly uses the infinitive form 'to reduce,' 'promote,' and 'create,' maintaining a parallel structure. In contrast, Option A incorrectly uses 'aims at reduce' and 'creating,' which disrupts the parallelism. Option B incorrectly uses 'aims to reducing' and mixes verb forms with 'create.' Option C maintains the 'to' before 'promote,' but mixes it with 'creating,' which is incorrect. Therefore, only Option D fits the grammatical structure required.

Q8. Choose the word with incorrect spelling:

• A. Immigrant
• B. Ancestors
• C. Montessori
• D. Pregmetic✓

Explanation: The correct answer is Pregmetic, which is a misspelling of the word pragmatic. The other options—Immigrant, Ancestors, and Montessori—are all spelled correctly and represent valid English words. Immigrant denotes a person who has moved to another country, Ancestors refers to family members from previous generations, and Montessori is a recognized educational methodology. Therefore, identifying 'Pregmetic' as the misspelled word is crucial for mastering vocabulary.

Q9. Choose the sentence in which “only” indicates that Jamila was the only person who spoke about her tiredness:

• A. Only Jamila said she was tired.✓
• B. Jamila only said she was tired.
• C. Jamila said only she was tired.
• D. Jamila said she was only tired.

Explanation: The correct answer is Option A: Only Jamila said she was tired. This sentence clearly indicates that Jamila was the only individual to express her tiredness, as 'only' directly modifies her name, emphasizing her exclusivity in the action of speaking. Option B (Jamila only said she was tired.) implies that her statement was limited to just mentioning her tiredness, but it does not clarify whether anyone else spoke about it, so the exclusivity of 'only' is ambiguous. Option C (Jamila said only she was tired.) focuses on what Jamila said rather than confirming that she was the only person who spoke about her tiredness. Here, 'only' does not effectively convey exclusivity regarding who spoke. Option D (Jamila said she was only tired.) suggests that Jamila was merely tired, without any implication that she was the only one discussing her feelings, thus losing the exclusivity intended by the use of 'only.'

Q10. A person has swollen lymph nodes after throat infection. What does this indicate?

• A. Failure of circulatory system
• B. Extra glucose storage
• C. Active immune response✓
• D. Blockage of digestive tract

Explanation: Swollen lymph nodes, also known as lymphadenopathy, typically occur when the body is fighting an infection. In the case of a throat infection, the lymph nodes in the neck often become enlarged as they produce more lymphocytes and filter out pathogens. This response is a sign that the immune system is active and working to eliminate the infection. Option A (Failure of circulatory system) is incorrect because swollen lymph nodes are specific to the immune response rather than circulatory issues. Option B (Extra glucose storage) does not relate to the context of swollen lymph nodes or immune function. Option D (Blockage of digestive tract) is also incorrect as it does not correlate with the lymphatic response associated with infections.

Q11. Monoclonal antibodies are useful in cancer diagnosis by:

• A. Replacing damaged tissue
• B. Changing the genetic code of cancer cells
• C. Killing healthy cells to reduce tumor spread
• D. Detecting specific tumor markers in samples✓

Explanation: Monoclonal antibodies are a key tool in cancer diagnostics because they can specifically bind to antigens that are expressed on the surface of cancer cells, known as tumor markers. This binding allows for the identification and quantification of these markers in various samples (e.g., blood, tissue), aiding in the diagnosis and monitoring of cancer progression. The other options do not accurately represent the function of monoclonal antibodies: they do not replace damaged tissue, alter genetic codes, or kill healthy cells. Instead, their specificity and ability to recognize tumor markers make them invaluable in the early detection and management of cancer.

Q12. Under a microscope, plant cells appeared rigid in shape, unlike flexible animal cells. Which structure explains this difference?

• A. Cell wall✓
• B. Vacuole
• C. Cytoskeleton
• D. Plasma membrane

Explanation: The correct answer is the cell wall, which is a distinguishing feature of plant cells that provides them with a rigid structure. The cell wall is made of cellulose and gives plant cells their shape and strength, preventing them from collapsing under pressure. The other options, while important cellular structures, do not account for the rigidity observed in plant cells. The vacuole primarily serves as a storage space and contributes to turgor pressure but does not provide structural rigidity. The cytoskeleton provides internal support and shape to both plant and animal cells but is flexible and not responsible for the rigid structure of plant cells. Lastly, the plasma membrane is a flexible barrier that allows for cell shape changes in animal cells and does not provide the rigidity seen in plant cells.

Q13. Which type of joint allows bending of the elbow joint and has a synovial cavity?

• A. Cartilaginous joint
• B. Fibrous joint
• C. Pubic symphysis
• D. Hinge joint✓

Explanation: The correct answer is Hinge joint. Hinge joints, such as the elbow, allow for flexion and extension movements, resembling the action of a door hinge. They have a synovial cavity that reduces friction and aids in movement. In contrast, cartilaginous joints (Option A) do not provide the same range of motion as hinge joints and are typically designed for stability rather than flexibility. Fibrous joints (Option B) are immovable and also lack a synovial cavity, thus cannot allow bending. The pubic symphysis (Option C) is a type of cartilaginous joint that allows limited movement, but it does not facilitate the bending motion required for the elbow joint. Therefore, the hinge joint is the only option that correctly fits the criteria outlined in the question.

Q14. If a round-seeded pea plant is self-fertilized and all of its offspring are also round-seeded:

• A. Both parents and offspring must be true breed✓
• B. Both parents and offspring may be true breed
• C. Only parents but not offspring will be true breed
• D. Only offspring but not parents will be true breed

Explanation: The correct answer is that both parents and offspring must be true breed. In Mendelian genetics, a true-breeding organism is homozygous for a specific trait and will produce offspring that have the same phenotype when self-fertilized. Since the question states that a round-seeded pea plant is self-fertilized and all offspring are also round-seeded, this indicates that the parent plant is likely homozygous for the round seed trait (RR), leading to all offspring being round-seeded (RR) as well. The other options suggest possibilities that contradict the principles of Mendelian inheritance.

Q15. A student observes a microorganism under a microscope that lacks a nucleus and is made of a single cell. Which classification fits this organism?

• A. Unicellular prokaryote✓
• B. Unicellular eukaryote
• C. Multicellular eukaryote
• D. Multicellular prokaryote

Explanation: The correct classification for the observed microorganism is Unicellular prokaryote because it lacks a nucleus and is made up of a single cell. Prokaryotes include bacteria and archaea, which are characterized by their simple cell structure. In contrast, Unicellular eukaryote and Multicellular eukaryote options are incorrect because they include organisms that possess a nucleus. The option Multicellular prokaryote is also incorrect since prokaryotes do not form multicellular structures. Thus, the unique combination of being unicellular and lacking a nucleus is what identifies this organism as a prokaryote.

Q16. In biotechnology, vaccines can be developed by cloning of:

• A. Gene for antigen of pathogen✓
• B. Gene for receptor of the patient
• C. Gene for antigen of patient
• D. Gene for antibody of patient

Explanation: The correct answer is Option A: Gene for antigen of pathogen. In vaccine development, the goal is to stimulate an immune response against a specific pathogen. This is achieved by cloning the gene that produces the antigen, which is a substance that induces an immune response. The other options are incorrect because:Option B refers to the gene for the receptor of the patient, which is not involved in vaccine creation.Option C suggests using the gene for the patient's antigen, which is not relevant as vaccines aim to target pathogens, not the individual.Option D involves the gene for antibodies of the patient, which again does not contribute to the creation of a vaccine.Thus, the focus should be on the pathogen's antigen gene for effective vaccine development.

Q17. Atrioventricular valve closed during which phase of cardiac cycle:

• A. Ventricular systole✓
• B. Ventricular diastole
• C. Atrial systole
• D. Atrial diastole

Explanation: The correct answer is ventricular systole because this is the phase of the cardiac cycle when the ventricles contract, leading to the closure of the atrioventricular valves to prevent backflow of blood into the atria. In contrast, during ventricular diastole, the ventricles are relaxed, and the valves are open, allowing blood to flow in. During atrial systole, the atria contract and push blood into the ventricles, which means the atrioventricular valves are open, and during atrial diastole, the atria are filling with blood, also with the valves open. Therefore, the only phase where the atrioventricular valves are definitively closed is during ventricular systole.

Q18. If “RRYy” is crossed with “rryy”, what will be the ratio of “RRYy” to “rryy” in F₂ generation?

• A. 9 : 3 : 3 : 1
• B. 3 : 1
• C. 1 : 3
• D. 1 : 1✓

Explanation: To determine the ratio of genotypes in the F₂ generation from the cross of "RRYy" (homozygous dominant for R, heterozygous for Y) and "rryy" (homozygous recessive for both traits), we first set up a Punnett square. The gametes from RRYy are RY and Ry, while the gametes from rryy are ry. When these are combined, the potential offspring genotypes are RRYy and rryy, giving us a 1:1 ratio. The other options presented do not apply to this specific genetic cross.

Q19. Name the idea of Darwin that best explains the ability of populations to reproduce those individuals who possess beneficial traits.

• A. Gene flow
• B. Genetic drift
• C. Artificial selection
• D. Natural selection✓

Explanation: The correct answer is Natural selection, which is a key mechanism of evolution as proposed by Charles Darwin. This concept explains how individuals with traits that enhance survival and reproduction are more likely to pass those traits on to the next generation, thus shaping the population over time. Gene flow and genetic drift involve changes in allele frequencies within populations but do not directly address the selective advantage of beneficial traits. Artificial selection involves human intervention in breeding, whereas natural selection occurs without human influence, based solely on environmental pressures.

Q20. The main function of the pharynx in respiratory system:

• A. Serves as passage for both food and air✓
• B. Produces mucus
• C. Produces voice
• D. Filters air

Explanation: The pharynx is a crucial component of the respiratory system as it serves as a common passage for both air and food. It leads to the larynx where air enters the trachea, and it also connects to the esophagus for the passage of food. This dual function highlights the pharynx's importance in maintaining both respiratory and digestive pathways. The other options are incorrect as they focus on functions that are not primarily associated with the pharynx. Mucus production is mainly a function of the nasal cavity, voice production occurs in the larynx, and air filtration primarily takes place in the nasal passages.

Q21. At least how many saccharide units must be present in polysaccharide?

• A. 1
• B. 2
• C. 10✓
• D. 11

Explanation: The correct answer is 10 because a polysaccharide is defined as a carbohydrate that consists of at least 10 monosaccharide units (saccharides) linked together through glycosidic bonds. Options 1 and 2 are incorrect as they refer to monosaccharides and disaccharides, respectively, which do not meet the criteria for polysaccharides. Option 11, while valid in terms of being a polysaccharide, does not address the minimum required number of saccharide units specified in the question.

Q22. A doctor taps below the knee and the leg kicks forward. What does this show?

• A. A conditional response
• B. Voluntary muscle contractions
• C. An involuntary reflex to external stimuli✓
• D. A delayed response due to brain processing

Explanation: The correct answer is An involuntary reflex to external stimuli. This reflex occurs due to the activation of the patellar reflex arc, which bypasses the brain and is processed at the spinal cord level. When the doctor taps the knee, sensory receptors in the tendon are stimulated, causing the quadriceps muscle to contract and the leg to kick forward automatically.Option A, 'A conditional response', is incorrect because the reflex action is not learned but rather an innate response. Option B, 'Voluntary muscle contractions', is also incorrect as the action is not consciously initiated. Lastly, Option D, 'A delayed response due to brain processing', is inaccurate because reflex actions are characterized by their immediate nature, occurring without delay.

Q23. If fertilization does not occur, which part of uterus degenerates?

• A. Myometrium
• B. Endometrium✓
• C. Perimetrium
• D. Cervix

Explanation: The correct answer is Endometrium. This is the layer of the uterus that prepares for potential pregnancy each cycle. If fertilization does not take place, the endometrium undergoes a process of degeneration, leading to menstruation. The other options are incorrect because the myometrium is involved in contractions and remains intact, the perimetrium serves as a protective outer layer, and the cervix acts as a passage but does not degenerate in the same way as the endometrium.

Q24. The main cause of acute kidney failure is:

• A. Less sweating
• B. Hypothermia
• C. Liver failure✓
• D. Drinking of excess water

Explanation: Acute kidney failure, also known as acute renal failure, occurs when the kidneys suddenly become unable to filter waste products from the blood. Among the options provided, liver failure is linked to acute kidney failure because it can lead to various complications, including metabolic imbalances that adversely affect kidney function. In contrast, less sweating and hypothermia are not directly associated with kidney failure, as they involve different physiological processes. Drinking excess water can lead to a condition known as water intoxication but does not usually result in acute kidney failure.

Q25. Which process uses mRNA to make protein at ribosomes?

• A. Replication
• B. Transcription
• C. Translation✓
• D. Cell fractionation

Explanation: The correct answer is Translation, which is the process that uses the information carried by mRNA to assemble amino acids into a protein at the ribosomes. During translation, the ribosome reads the mRNA sequence and, with the help of transfer RNA (tRNA), links the appropriate amino acids together to form a polypeptide chain, ultimately folding into a functional protein.In contrast, Replication involves duplicating DNA, which is necessary for cell division but does not relate to protein synthesis. Transcription is the first step of gene expression, where a specific segment of DNA is transcribed to produce mRNA, but it does not directly create proteins. Lastly, Cell fractionation refers to separating cellular components to study them, which is unrelated to the processes of protein synthesis.

Q26. Which of the following is the sexually transmitted disease?

• A. Syphilis✓
• B. Lung Cancer
• C. Tuberculosis
• D. Autoimmune disorders

Explanation: The correct answer is Syphilis, which is a well-known sexually transmitted disease caused by the bacterium Treponema pallidum. It is transmitted through sexual contact, making it a classic example of a sexually transmitted infection.In contrast, Lung Cancer is not related to sexual transmission, as it is primarily linked to lifestyle factors such as smoking.Tuberculosis is an infectious disease spread through the air, not through sexual contact, making it a respiratory disease rather than an STD.Finally, Autoimmune disorders are conditions where the immune system mistakenly attacks healthy tissues, and they are not transmitted between individuals, thus they cannot be classified as sexually transmitted diseases.

Q27. During diastole, the heart chambers:

• A. Relax and fill with blood✓
• B. Contract strongly
• C. Eject blood into arteries
• D. Remain closed

Explanation: During diastole, the heart chambers relax, allowing them to fill with blood from the veins. This is a crucial part of the cardiac cycle that prepares the heart for the next contraction. The correct option is (A), as it accurately describes the process occurring during this phase. Options (B) and (C) are incorrect because they describe actions that occur during systole, where the heart contracts to pump blood out. Option (D) is misleading; although the heart valves may close to prevent backflow, the chambers themselves are not closed; they are simply filling with blood in preparation for the next heartbeat.

Q28. The Golgi apparatus is structurally made of a series of flattened membrane-bounded sacs:

• A. Grana
• B. Cristae
• C. Cisternae✓
• D. Vesicles

Explanation: The correct answer is Cisternae, which are the flattened membrane-bound sacs that constitute the Golgi apparatus. These structures play a critical role in the modification, sorting, and packaging of proteins and lipids for secretion or delivery to other organelles.Option Grana is incorrect because grana are related to chloroplasts and photosynthesis, not the Golgi apparatus. Option Cristae is also incorrect as they refer to the inner folds of mitochondria. Lastly, while Vesicles are important for transporting materials, they do not describe the structural components of the Golgi apparatus itself.

Q29. Kidneys under the effect of Antidiuretic Hormone (ADH) produce:

• A. Hypotonic urine with decreased volume
• B. Hypotonic urine with increased volume
• C. Hypertonic urine with decreased volume✓
• D. Hypertonic urine with increased volume

Explanation: The correct answer is Option C: Hypertonic urine with decreased volume. Antidiuretic Hormone (ADH) acts on the kidneys to increase the reabsorption of water in the collecting ducts, which leads to the production of concentrated (hypertonic) urine and reduced urine volume. Options A and B incorrectly describe the urine as hypotonic, which does not occur under the influence of ADH. Option D incorrectly states that urine volume increases while being hypertonic, which is also contrary to ADH's effect.

Q30. Which type of change is a nerve impulse?

• A. Electrical and mechanical change
• B. Chemical and mechanical change
• C. Electrical and chemical change✓
• D. Chemical change only

Explanation: The correct answer is Electrical and chemical change (Option C) because nerve impulses are generated by electrical changes in the neuron membrane, which lead to the release of neurotransmitters at synapses, representing a chemical change. The other options are incorrect as they either omit the electrical aspect or incorrectly emphasize mechanical changes that are not relevant to nerve impulse transmission.

Q31. A person has swollen lymph nodes after throat infection. What does this indicate?

• A. Failure of circulatory system
• B. Extra glucose storage
• C. Active immune response✓
• D. Blockage of digestive tract

Explanation: Swollen lymph nodes, especially after a throat infection, indicate that the body is mounting an active immune response to fight off the infection. The lymph nodes are part of the lymphatic system, which plays a crucial role in the immune system by filtering pathogens and housing immune cells. In this context, the correct answer is that the swollen lymph nodes signify an active immune response as they are producing more immune cells to combat the infection. The other options are incorrect because they do not relate to the immune function or implications of swollen lymph nodes.

Q32. Which of the following fluid flows through the lymphatic vessels?

• A. Plasma
• B. Lymph✓
• C. Bile
• D. Serum

Explanation: The lymphatic system is responsible for transporting lymph, a fluid that contains white blood cells, proteins, and other substances crucial for immune function. Lymph is collected from interstitial fluid and flows through lymphatic vessels, eventually returning to the bloodstream. Plasma is part of the blood and is not found in lymphatic vessels, which are specifically designed to carry lymph. Bile, produced by the liver, is involved in digestion and does not enter the lymphatic system. Serum is a component of blood that is separate from lymph and does not circulate through lymphatic vessels. Therefore, the only correct option is lymph.

Q33. Which one of the following is the most common nitrogenous waste excreted in urine of a healthy human?

• A. Ammonia
• B. Urea✓
• C. Uric Acid
• D. Creatinine

Explanation: The correct answer is Urea, which is the most common nitrogenous waste excreted in human urine. It is produced when the liver converts ammonia, which is toxic, into urea, making it safer for excretion. Urea is less toxic and more water-soluble than ammonia, allowing it to be excreted efficiently by the kidneys. On the other hand, ammonia is typically excreted directly by aquatic organisms due to its high toxicity and solubility in water, making it unsuitable for terrestrial mammals like humans. Uric acid is primarily found in the excretion of birds and reptiles, as it is less toxic and conserves water, while creatinine is a byproduct of muscle metabolism and is not a primary nitrogenous waste product.

Q34. Hippocampus mainly involved in:

• A. Vision and hearing reflexes
• B. Voluntary muscle movement
• C. Memory storage✓
• D. Speech production

Explanation: The correct answer is memory storage (Option C). The hippocampus is a critical region of the brain involved in the consolidation of information from short-term memory to long-term memory, making it essential for the storage of memories.Options A (Vision and hearing reflexes) and B (Voluntary muscle movement) are incorrect because they involve different brain areas that focus on sensory processing and motor control, respectively. Option D (Speech production) is also incorrect, as it is primarily managed by specific regions such as Broca's area and Wernicke's area, rather than the hippocampus.

Q35. The covalently bonded non-protein part of enzyme is called:

• A. Activator
• B. Prosthetic group✓
• C. Coenzyme
• D. Apoenzyme

Explanation: The correct answer is prosthetic group because it refers to a non-protein component that is covalently bonded to an enzyme, thus playing a crucial role in its activity. Activators, while they may enhance enzyme function, do not specifically indicate a covalently bonded non-protein part. Coenzymes are also important cofactors but they typically associate transiently and are not covalently bound. Apoenzymes are the protein part of enzymes that require a cofactor to be active, but they do not describe the covalently bonded non-protein part mentioned in the question.

Q36. The outer surface of the axon membrane in a resting neuron is:

• A. Negative due to sodium ions
• B. Positive due to sodium ions✓
• C. Positive due to potassium ions
• D. Neutral due to balanced ions

Explanation: In a resting neuron, the outer surface of the axon membrane is positively charged due to the higher concentration of sodium ions outside the neuron compared to the inside, where potassium ions are more prevalent. This charge difference creates the resting membrane potential, essential for the transmission of nerve impulses. The incorrect options fail to recognize this ion distribution and its effect on the membrane potential. Option A incorrectly attributes a negative charge to sodium ions, while Option C misattributes a positive charge to potassium ions, which are actually more concentrated inside the neuron. Option D incorrectly states that the charge is neutral, ignoring the established ionic gradients.

Q37. Which class of animals excrete ammonia as their primary nitrogenous waste?

• A. Uricotelic
• B. Urotelic
• C. Ammonotelic✓
• D. Ureotelic

Explanation: The correct answer is Ammonotelic, as these animals primarily excrete ammonia, which is a direct byproduct of protein metabolism. This is primarily seen in aquatic animals, such as fish, which can afford to lose large amounts of water. In contrast, Uricotelic animals excrete uric acid, which conserves water and is typical of terrestrial organisms. Urotelic animals excrete urea, which is less toxic and is seen in mammals and amphibians. Lastly, Ureotelic refers to organisms that convert ammonia to urea for excretion. Understanding these classifications is essential in the study of animal physiology and excretion.

Q38. Which of the following best describes the direction of impulse traveling in a typical neuron?

• A. Axon → dendrite → cell body
• B. Dendrite → cell body → axon✓
• C. Synapse → axon → dendrite
• D. Cell body → dendrite → axon

Explanation: An impulse in a neuron travels in a specific direction: it starts at the dendrites, which receive signals from other neurons or stimuli. The signal then passes through the cell body, where it is processed, and finally travels down the axon to be transmitted to the next neuron or target cell. Therefore, the correct answer is Option B: Dendrite → cell body → axon.Options A, C, and D incorrectly depict the flow of impulses and do not follow the established direction of neural communication.

Q39. Homopolysaccharide found in the cell wall of fungi and exoskeleton of arthropods is:

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

Explanation: The correct answer is Chitin because it is a homopolysaccharide that serves as a structural component in the cell walls of fungi and the exoskeletons of arthropods. Unlike cellulose, which is found in plant cell walls, glycogen, which is used for energy storage in animals, and starch, which serves as an energy reserve in plants, chitin is unique to fungi and arthropods. Its composition of N-acetylglucosamine units distinguishes it from other polysaccharides, reinforcing its role in providing structural integrity.

Q40. The most abundant lipids in living things are:

• A. Terpenes
• B. Waxes
• C. Steroids
• D. Acylglycerols✓

Explanation: Acylglycerols, or triglycerides, are the most abundant lipids in living organisms, serving critical roles in energy storage and insulation. They are formed from glycerol and three fatty acids, making them a significant source of energy. In contrast, terpenes, waxes, and steroids, while important in various biological functions, do not match the abundance of acylglycerols. Terpenes are more associated with plant metabolism, waxes provide protective barriers, and steroids serve structural and regulatory functions, but none are as prevalent as acylglycerols in living organisms.

Q41. Name the type of bond that joins amino acids to form a polypeptide chain:

• A. Hydrogen bond
• B. Ionic bond
• C. Glycosidic bond
• D. Peptide bond✓

Explanation: The correct answer is the peptide bond, which is a covalent bond that forms between the amino group of one amino acid and the carboxyl group of another. This bond is crucial for the formation of polypeptide chains, which make up proteins. The other options are incorrect because:Hydrogen bonds are weak attractions that can occur between molecules but do not form the backbone of polypeptides.Ionic bonds involve the electrostatic attraction between charged particles, which is not how amino acids are connected.Glycosidic bonds are specific to carbohydrates and do not play a role in linking amino acids.Thus, understanding the role of different types of bonds is key to mastering the structure of biological molecules such as proteins.

Q42. Which of the following is not a globular protein?

• A. Enzyme
• B. Hormone
• C. Channel protein
• D. Collagen✓

Explanation: The correct answer is Collagen because it is classified as a fibrous protein, which is characterized by its elongated structure and role in providing structural support in tissues like skin, tendons, and cartilage. In contrast, enzymes, hormones, and channel proteins are all globular proteins that are typically soluble in water and participate in various functional roles within the organism. Enzymes catalyze biochemical reactions, hormones regulate physiological processes, and channel proteins facilitate the movement of substances across cell membranes.

Q43. Atrioventricular valve closed during which phase of cardiac cycle:

• A. Ventricular systole✓
• B. Ventricular diastole
• C. Atrial systole
• D. Atrial diastole

Explanation: The correct answer is Ventricular systole because during this phase, the ventricles contract, which causes the atrioventricular valves to close to prevent backflow into the atria. In contrast, during ventricular diastole, the ventricles are relaxed, and the valves are open for blood flow; during atrial systole, the atria contract and push blood into the ventricles, keeping the atrioventricular valves open; and in atrial diastole, the atria are filling with blood and also maintain open valves. Therefore, only during ventricular systole do the atrioventricular valves close.

Q44. Which specialized cells of liver perform phagocytic function?

• A. Kupffer cells✓
• B. Schwann cells
• C. Parietal cells
• D. Chief cells

Explanation: The correct answer is Kupffer cells, which are specialized macrophages found in the liver that play a critical role in the immune system by engulfing and digesting pathogens and cellular debris. They help maintain homeostasis in the liver and contribute to the body's defense mechanisms.The other options are incorrect because:Schwann cells are involved in nerve function and do not participate in immune responses.Parietal cells are involved in gastric function, specifically in acid secretion, and do not have a role in phagocytosis.Chief cells also function in the stomach, mainly producing digestive enzymes, and are not related to liver immunity.

Q45. According to Darwin, the main force behind evolution is:

• A. Migration
• B. Genetic mutation
• C. Artificial selection
• D. Natural selection✓

Explanation: According to Darwin, the main force behind evolution is natural selection, which posits that individuals with advantageous traits are more likely to survive and reproduce, thus passing these traits to the next generation. While migration can influence the distribution of species, genetic mutation provides the raw material for evolution, and artificial selection shows how selective pressures can alter species, none of these mechanisms drive evolutionary change in the same way that natural selection does. Natural selection is critical in explaining the adaptation of organisms to their environments over time.

Q46. Beside fertilization, the function of fallopian tube is:

• A. Nourishment of embryo
• B. Transport of ovum towards uterus✓
• C. Secretion of female hormones
• D. Implantation of zygote

Explanation: The correct answer is the transport of the ovum towards the uterus. The fallopian tubes play an essential role in carrying the ovum from the ovaries to the uterus, where fertilization can occur if sperm is present. Other options are incorrect because:Nourishment of the embryo takes place in the uterus once implantation occurs.Secretion of female hormones is a function of the ovaries, not the fallopian tubes.Implantation of the zygote happens in the uterus, not in the fallopian tubes where the zygote may initially travel after fertilization.

Q47. Which property of water allows it to stick to polar surface like wood?

• A. Density
• B. Adhesion✓
• C. Cohesion
• D. Non-polar attraction

Explanation: The correct answer is Adhesion because this property describes the attraction between water molecules and other polar surfaces, such as wood. Water molecules are polar, meaning they have a slight positive charge on one side and a slight negative charge on the other. This polar nature allows water to form bonds with other polar materials, leading to the sticking effect described in the question.Density is incorrect because it measures how compact a substance is, not its ability to stick to surfaces. Cohesion is also incorrect because it refers to the attraction between water molecules, not their interaction with other materials. Finally, Non-polar attraction is irrelevant here, as it relates to interactions between non-polar substances, which do not apply to the properties of water in this context.

Q48. A food sample contains long chains of amino acids bounded together. This indicates the presence of:

• A. Carbohydrates
• B. Lipids
• C. Proteins✓
• D. Nucleic acids

Explanation: The correct answer is Proteins. Proteins are composed of long chains of amino acids that are linked together through peptide bonds. This structural characteristic is fundamental to their function and classification. In contrast, carbohydrates are primarily made of sugars, lipids are made of fatty acids, and nucleic acids are made of nucleotides. None of these other biological molecules consist of long chains of amino acids, which makes them distinct from proteins.

Q49. In which process do cells release energy from oxidation of food molecules?

• A. Cellular respiration✓
• B. Photosynthesis
• C. DNA replication
• D. Protein synthesis

Explanation: The correct answer is Cellular respiration, which is the biochemical process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. This process is essential for producing ATP, the energy currency of the cell. In contrast, Photosynthesis is the process used by plants to convert sunlight into chemical energy, storing it in glucose rather than releasing it. DNA replication and Protein synthesis are critical cellular processes, but they do not involve the oxidation of food molecules to release energy.

Q50. How many NADH are produced when one Acetyl CoA is oxidized during Krebs’s cycle?

• A. 1
• B. 3✓
• C. 2
• D. 6

Explanation: When one Acetyl CoA enters the Krebs cycle, it undergoes a series of reactions that result in the production of 3 NADH, along with 1 FADH2 and 1 GTP (or ATP). These NADH molecules are crucial for the next stage of cellular respiration—the electron transport chain—where they are utilized to generate ATP through oxidative phosphorylation. The other options are incorrect: Option A suggests only 1 NADH is produced, which is not enough; Option C's claim of 2 NADH is also too low; and Option D's 6 NADH is an overestimate, as the maximum produced from one Acetyl CoA is 3.

Q51. Which of the following best describes glycoproteins?

• A. Proteins linked with carbohydrates✓
• B. Proteins linked with DNA
• C. Proteins linked with lipids
• D. Proteins linked with minerals

Explanation: Glycoproteins are proteins that have carbohydrate groups attached to them, which play critical roles in various biological functions including cell-cell recognition, signaling, and immune responses. The correct option (A) specifies that glycoproteins are proteins linked with carbohydrates, accurately describing their structure and function. The other options are incorrect as they refer to different types of conjugated molecules: option B refers to nucleoproteins (protein-DNA complexes), option C refers to lipoproteins (protein-lipid complexes), and option D mentions a less common interaction with minerals, which does not define any specific class of biomolecules.

Q52. The function which is common between Cerebellum and Hippocampus is:

• A. Equilibrium
• B. Memory formation✓
• C. Body positioning
• D. Sexual arousal

Explanation: The correct answer is Memory formation. The Hippocampus is well-known for its role in forming new memories, particularly declarative memories (facts and events). While the Cerebellum is predominantly involved in motor control and coordination, it also contributes to certain types of memory, specifically procedural memory (skills and habits). Therefore, both structures play a role in the broader category of memory, albeit in different forms.The other options are incorrect because:Equilibrium: This function is largely the responsibility of the Cerebellum alone, without involvement from the Hippocampus.Body positioning: Similar to equilibrium, this is a function primarily associated with the Cerebellum and does not overlap with the Hippocampus.Sexual arousal: This process is not primarily linked to the functions of either the Cerebellum or Hippocampus, making it irrelevant in this context.

Q53. The water content of human kidney is regulated by ADH. Which gland is involved in its secretion?

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

Explanation: The correct answer is the pituitary gland, as it secretes antidiuretic hormone (ADH), which is crucial for regulating water balance in the body by controlling water reabsorption in the kidneys. The other options are incorrect because the adrenal gland is involved in producing cortisol and aldosterone, which regulate blood pressure and electrolyte balance; the thyroid gland primarily regulates metabolism through hormones like thyroxine; and the parathyroid gland regulates calcium levels in the blood through parathyroid hormone (PTH). None of these glands are responsible for the secretion of ADH.

Q54. In males, which of the following is considered a urogenital organ?

• A. Urethra✓
• B. Ureter
• C. Urinary bladder
• D. Vas deferens

Explanation: The correct answer is the urethra, as it serves dual functions in males, transporting both urine and semen. The ureter and urinary bladder are part of the urinary system, focused solely on urine transport and storage, respectively, and do not participate in reproductive functions. The vas deferens is a part of the male reproductive system but is not involved in urinary functions, hence it does not qualify as a urogenital organ.

Q55. For which reaction, the value of Kc increases with increase in temperature?

• A. CH4 + O2 → CO2 + H2O
• B. NaOH + HCl → NaCl + H2O
• C. 2SO2 + O2 →2SO3
• D. H2 + I2→2HI✓

Explanation: The correct answer is Option D: H2 + I2→2HI because this reaction is endothermic. According to Le Chatelier's Principle, if the temperature is increased in an endothermic reaction, the equilibrium shifts to the right, resulting in an increase in Kc. In contrast, the other reactions are exothermic. For Option A ( CH4 + O2 → CO2 + H2O), Option B (NaOH + HCl → NaCl + H2O), and Option C (2SO2 + O2 →2SO3), increasing temperature causes the equilibrium to shift towards the reactants, thus decreasing their respective Kc values.

Q56. The most common type of arthritis is:

• A. Gout
• B. Rheumatoid arthritis
• C. Osteoarthritis✓
• D. Spondylitis

Explanation: Osteoarthritis is the correct answer as it is the most prevalent form of arthritis, affecting millions of individuals worldwide, especially those over the age of 50. It results from the gradual wear and tear of joint cartilage and is often associated with aging.Gout, while painful and characterized by sudden attacks, is less common and is caused by a buildup of uric acid. Rheumatoid arthritis is an autoimmune condition that affects fewer people compared to osteoarthritis. Spondylitis, which specifically affects the spine, is also less common and affects a more specific population.

Q57. Overconsumption of which of the following foods increases the risk of calcium oxalate stone?

• A. Leafy vegetables✓
• B. Fruits contain Vitamin C
• C. Fruits contain high fiber
• D. Whole grains

Explanation: Calcium oxalate stones are the most common type of kidney stones, and their formation is influenced by dietary intake. Overconsumption of leafy vegetables can lead to an excess intake of oxalates, which can bind with calcium in the urine and form stones. Although fruits with high Vitamin C content can contribute to oxalate levels, they are not as significant a risk factor as leafy vegetables. Fruits that are high in fiber and whole grains are generally safe and do not contribute to stone formation. Therefore, the correct answer is leafy vegetables.

Q58. The other name for interstitial cells in male testes is:

• A. Leydig cell✓
• B. Spermatogonia cell
• C. Sertoli cell
• D. Spermatocyte

Explanation: The correct answer is Leydig cell, which is another name for interstitial cells found in the male testes. These cells play a vital role in the endocrine function of the testes by producing testosterone, which is crucial for male reproductive development and functions.The other options are incorrect for the following reasons: Spermatogonia cells are the precursor cells that give rise to sperm, but they do not produce hormones. Sertoli cells are supportive cells in the seminiferous tubules that aid in the development of sperm but are not interstitial cells. Lastly, spermatocytes are the cells undergoing division to eventually form sperm and are not involved in hormone production.

Q59. Which product is produced by genetically modified bacteria for patients with Diabetes mellitus?

• A. Insulin✓
• B. Erythropoietin
• C. Growth hormone
• D. Vaccine

Explanation: The correct answer is Insulin, which is a vital hormone for individuals with Diabetes mellitus. Genetically modified bacteria, specifically E. coli, are engineered to produce insulin, making it easier and more efficient to supply this essential medication. The other options are incorrect because erythropoietin is produced in mammalian cells, growth hormone is not specifically for diabetes treatment, and vaccines do not address the management of diabetes directly.

Q60. Binding of hemoglobin with oxygen is catalyzed by the enzyme:

• A. Carbonic anhydrase✓
• B. Carboxylase
• C. Oxygenase
• D. Dehydrogenase

Explanation: The correct answer is Carbonic anhydrase. While this enzyme is primarily known for its role in the conversion of carbon dioxide and water into bicarbonate and protons, it is indirectly related to respiration and gas exchange, but it does not catalyze the direct binding of oxygen to hemoglobin. Hemoglobin binds oxygen through a reversible process that does not require an enzyme. The other options—carboxylase, oxygenase, and dehydrogenase—are all enzymes that facilitate different biochemical reactions but do not play a role in the binding of oxygen to hemoglobin.

Q61. Which changes occur in the endometrium during the proliferative phase of menstrual cycle?

• A. It begins to shed
• B. It regenerates and thickens
• C. It becomes secretory✓
• D. No change occurs

Explanation: During the proliferative phase of the menstrual cycle, the endometrium undergoes significant regeneration and thickening in preparation for a potential implantation of an embryo. The correct answer, while it mentions secretory characteristics, refers to changes that actually occur in the luteal phase. Therefore, the most accurate description is that the endometrium regenerates and thickens. The other options are incorrect because the shedding of the endometrium occurs during the menstrual phase, the endometrium does not remain unchanged, and it does not become secretory until after ovulation in the luteal phase.

Q62. Transfer of phosphate from one compound to another requires an enzyme called:

• A. Oxidoreductase
• B. Transferase✓
• C. Hydrolase
• D. Ligase

Explanation: The correct answer is Transferase because these enzymes are specifically designed to facilitate the transfer of functional groups, such as phosphate, between molecules. In this case, the question focuses on the transfer of phosphate, which directly falls under the function of transferases.Oxidoreductase is incorrect because it deals with electron transfer, not group transfer. Hydrolase is also incorrect as it involves the addition of water to break bonds rather than transferring groups. Lastly, Ligase is incorrect because it is responsible for joining molecules together, which does not align with the question about transferring phosphate.

Q63. Linkage of genes in Drosophila was first discovered by:

• A. Thomas Hunt Morgan✓
• B. Alfred Sturtevant
• C. Gregor Mendel
• D. Hugo de Vries

Explanation: Thomas Hunt Morgan was the first scientist to demonstrate the concept of gene linkage using Drosophila (fruit flies) in the early 20th century. His experiments showed that certain traits were inherited together more often than would be expected by chance, indicating that the genes controlling those traits were located on the same chromosome. This was a pivotal moment in genetics, leading to the formulation of the chromosome theory of inheritance.While Alfred Sturtevant contributed significantly to genetics by mapping genes, he built upon Morgan's foundational work rather than discovering linkage himself. Gregor Mendel, known for his pioneering studies in heredity, did not study Drosophila and therefore cannot be credited with gene linkage. Similarly, Hugo de Vries focused more on the role of mutations in evolution and did not conduct research that directly addressed gene linkage in Drosophila.

Q64. Which of the following structures prevents blood from flowing back into atria?

• A. Semilunar valves
• B. Bicuspid & tricuspid valves✓
• C. Chordae tendinae
• D. Papillary muscles

Explanation: These atrioventricular valves prevent backflow into atria during ventricular contraction.

Q65. Which of the following is a characteristic of a non-competitive enzyme inhibitor?

• A. Binds to the enzyme active site
• B. Can be overcome by increasing substrate concentration
• C. Increases the speed of the reaction
• D. Point of action is allosteric site✓

Explanation: The correct answer is Option D: Point of action is allosteric site. Non-competitive inhibitors bind to an allosteric site, which alters the enzyme's conformation and reduces its activity regardless of substrate concentration. This is different from competitive inhibitors, which bind directly to the active site and can be overcome by increasing substrate concentration. Options A, B, and C are incorrect because they describe characteristics of competitive inhibition or misrepresent the effects of non-competitive inhibitors on enzyme kinetics.

Q66. The appendix is attached to which part of large intestine?

• A. Rectum
• B. Caecum✓
• C. Colon
• D. Ileum

Explanation: The correct answer is Caecum, as the appendix is a small pouch that is attached to the caecum, which is the beginning of the large intestine. The appendix is situated at the junction where the small intestine (ileum) meets the large intestine. The other options are incorrect because:Rectum: This is the terminal section of the large intestine and is not connected to the appendix.Colon: While the colon is part of the large intestine, it comes after the caecum and does not house the appendix.Ileum: This is the last part of the small intestine and does not connect to the appendix, which is a feature of the large intestine.

Q67. If a male with hemophilia marries a non-carrier female, what is the likelihood of their sons inheriting the condition?

• A. 50%
• B. 100%
• C. 0%✓
• D. 25%

Explanation: Hemophilia is an X-linked recessive disorder. Males have only one X chromosome (XY), and they inherit their Y chromosome from their father and the X chromosome from their mother. In this case, the male with hemophilia has the genotype XhY, where Xh represents the X chromosome with the hemophilia gene. Since the male passes his Y chromosome to his sons, they receive their X chromosome from their non-carrier mother, who has the genotype XX. Therefore, all sons will receive a normal X chromosome from their mother, resulting in a 0% chance of inheriting hemophilia. The other options incorrectly assess the probability based on a misunderstanding of X-linked inheritance.

Q68. Which of the following is NOT related to DNA?

• A. Adenine
• B. Thymine
• C. Uracil✓
• D. Guanine

Explanation: The correct answer is Uracil, which is not related to DNA. DNA contains four primary nitrogenous bases: adenine, thymine, guanine, and cytosine. Uracil is found in RNA, where it replaces thymine and pairs with adenine. The other options—adenine, thymine, and guanine—are all integral components of DNA, making them incorrect choices in this context.

Q69. Why Lamarck is being remembered till today?

• A. Due to his rejected but appealing theory of heredity✓
• B. Due to his universally acceptable theory of evolution
• C. Due to his accepted theory of heredity
• D. Due to his theory of evolution by natural selection

Explanation: Lamarck is remembered today primarily for his rejected but intriguing theory of heredity, which suggested that organisms could pass on traits acquired during their lifetime to their offspring. This idea sparked discussions and debates about evolution long before Darwin's theory of natural selection became widely accepted. While his concepts have been disproven, they remain significant in the history of evolutionary thought and continue to be a point of interest in discussions about heredity and evolution. The other options are incorrect because they either misrepresent Lamarck's contributions or attribute concepts to him that belong to other theorists, particularly Charles Darwin.

Q70. Which of the following neurons conduct impulses from sensory receptors to CNS?

• A. Sensory neurons✓
• B. Motor neurons
• C. Efferent neurons
• D. Interneurons

Explanation: The correct answer is Sensory neurons because they are responsible for transmitting sensory information from sensory receptors (like skin, eyes, and ears) to the central nervous system (CNS) for processing. In contrast, Motor neurons carry signals away from the CNS to muscles or glands, Efferent neurons are a type of motor neuron that also sends impulses away from the CNS, and Interneurons serve as connectors within the CNS itself, facilitating communication between sensory and motor neurons but not conducting impulses from sensory receptors directly to the CNS.

Q71. Guanine–cytosine pairs enhance DNA stability due to:

• A. Larger size
• B. Closer pairing
• C. More hydrogen bonds✓
• D. Double ring structure in both

Explanation: Guanine–cytosine pairs enhance DNA stability primarily due to the formation of three hydrogen bonds between them, compared to the two hydrogen bonds that adenine and thymine form. This additional hydrogen bond significantly increases the stability of DNA molecules, making them less likely to separate under physiological conditions. The other options do not directly address the key factor that contributes to DNA stability:Larger size: Size does not primarily influence stability.Closer pairing: Proximity alone does not enhance stability; it is the bonding interactions that matter.Double ring structure: While structural characteristics are important, they do not directly enhance stability as much as the number of hydrogen bonds.

Q72. Which of the following substances pass through the glomerulus into Bowman’s capsule?

• A. Glucose✓
• B. Red blood cells
• C. Platelets
• D. Albumin

Explanation: The correct answer is Glucose, as it is a small molecule that can pass through the glomerulus into Bowman’s capsule during the filtration process. The glomerulus acts as a filtration barrier, allowing only small molecules and ions to pass while retaining larger components of the blood, such as red blood cells and platelets. Red blood cells and platelets are both too large to be filtered and therefore do not enter Bowman’s capsule. Albumin, a protein, is also retained in the bloodstream under normal circumstances; its presence in urine can indicate kidney issues.

Q73. Shivering thermogenesis involves:

• A. Voluntary muscle contraction
• B. Involuntary muscle contraction✓
• C. Dehydration
• D. Hormone secretion

Explanation: Shivering thermogenesis is a physiological response characterized by involuntary muscle contractions that occur when the body is exposed to cold temperatures. These rapid muscle contractions generate heat, helping to maintain core body temperature. Option A, voluntary muscle contraction, is incorrect because shivering is not consciously controlled. Option C, dehydration, is unrelated to the mechanism of heat production via shivering. Option D, hormone secretion, while relevant to thermoregulation processes, does not specifically pertain to the action of shivering.

Q74. The best way to avoid AIDS is:

• A. Preventive measures✓
• B. Vaccination
• C. Medication
• D. Shots

Q75. Which of the following biological molecules releases highest energy from its one gram?

• A. Carbohydrates
• B. Lipids✓
• C. Protein
• D. Water

Explanation: The correct answer is Lipids, as they are the most energy-rich of the biological molecules, providing about 9 kilocalories per gram. This high energy content is due to their long hydrocarbon chains, which release more energy upon oxidation compared to carbohydrates and proteins, each of which yields approximately 4 kilocalories per gram. Water, on the other hand, does not provide any energy at all, as it is not a source of calories.

Q76. Which group of viruses can cause diseases like influenza, measles, and rabies?

• A. Plant viruses
• B. Animal viruses✓
• C. Fungal viruses
• D. Bacteriophages

Explanation: The correct answer is Animal viruses, as these are the types of viruses that can lead to diseases like influenza, measles, and rabies, which affect animals and humans. Plant viruses target plant cells and do not impact animal health, while fungal viruses affect fungi and bacteriophages are specific to bacteria. Therefore, the other options do not relate to the diseases mentioned in the question.

Q77. If a disease is caused due to a defective gene located on the X chromosome, then the defective gene can only be transmitted to male offspring by the:

• A. Female gamete✓
• B. Male gamete
• C. Bacteria
• D. Mutation

Explanation: The correct answer is Female gamete because in humans, males inherit their X chromosome from their mothers. A defective gene located on the X chromosome can only be passed to male offspring via the egg (female gamete). Males contribute a Y chromosome to their sons, not an X chromosome. Therefore, options involving male gametes, bacteria, or mutation are incorrect as they do not relate to the inheritance of X-linked traits.

Q78. Which of the following surrounds myofibril in skeletal muscle that stores and distributes calcium ions during muscle functioning?

• A. Sarcolemma
• B. Sarcoplasmic reticulum✓
• C. Transverse tubules
• D. Sarcoplasm

Explanation: The correct answer is Sarcoplasmic reticulum. This organelle is specialized for storing calcium ions, which are essential for the contraction of skeletal muscle fibers. When a muscle is stimulated, calcium ions are released from the sarcoplasmic reticulum into the cytoplasm, triggering the interaction between actin and myosin filaments, leading to muscle contraction. In contrast, the Sarcolemma is the outer membrane of the muscle cell and is not involved in calcium storage. Transverse tubules function to transmit electrical signals into the muscle fiber but do not store calcium themselves. Sarcoplasm is the fluid inside the muscle cell that contains various organelles but does not play a direct role in calcium ion storage.

Q79. Water can circulate in living organisms due to:

• A. Surface tension and polarity
• B. Cohesion and adhesion✓
• C. Solubility in cells
• D. Stable liquid range

Explanation: The correct answer is Cohesion and adhesion. Cohesion allows water molecules to stick together, enabling the formation of water columns that can be pulled through plant vessels during transpiration. Adhesion allows water to cling to other surfaces, such as the walls of plant vessels, aiding in the upward movement of water against gravity. Option A, Surface tension and polarity, while related to water's behavior, do not directly account for its circulation. Option C, Solubility in cells, refers to water's ability to dissolve substances but does not explain its movement. Finally, Option D, Stable liquid range, describes a physical property of water rather than its transport mechanisms. Thus, Cohesion and adhesion are the primary factors that enable water to circulate in living organisms.

Q80. What is the chemical composition of chromosomes?

• A. RNA and lipids
• B. DNA and proteins✓
• C. Carbohydrates and nucleic acids
• D. Proteins and carbohydrates

Explanation: Chromosomes are made up of DNA and proteins, specifically histones, which help in organizing and condensing the DNA into a structure that fits within the cell nucleus. This combination allows for the efficient packaging of genetic material and plays a crucial role in gene regulation. The other options are incorrect as they include components that do not constitute the primary structure of chromosomes. RNA and lipids (Option A) do not relate to chromosome composition. Carbohydrates (Options C and D) also do not significantly contribute to the structure of chromosomes, as their main components are DNA and proteins.

Q81. Which part of small intestine is responsible for nutrient absorption?

• A. Duodenum
• B. Jejunum✓
• C. Ileum
• D. Rectum

Explanation: The correct answer is Jejunum, as it is specifically adapted for the absorption of nutrients from digested food. It has a highly folded surface with numerous villi and microvilli that increase the surface area, allowing for efficient nutrient uptake. The Duodenum, while crucial for the initial stages of digestion, mainly processes food rather than absorbing nutrients. The Ileum, although it absorbs some nutrients, primarily focuses on absorbing vitamin B12 and bile acids rather than the majority of nutrients. Lastly, the Rectum is not involved in nutrient absorption at all, as its role is to store waste before elimination.

Q82. Name the biomolecule essential for information storage and transmission within cells.

• A. Carbohydrates
• B. Lipids
• C. Nucleic acids✓
• D. Proteins

Explanation: The correct answer is Nucleic acids, which include DNA and RNA. These biomolecules are fundamental to the storage of genetic information (DNA) and its transmission (RNA) during processes such as transcription and translation. In contrast, Carbohydrates serve mainly as energy sources and structural elements, Lipids are crucial for membrane structure and energy storage, and Proteins are involved in many cellular functions but do not directly handle genetic information.

Q83. Which of the following is a route of HIV transmission?

• A. Unhygienic living conditions
• B. Blood transfusion with contaminated blood✓
• C. Hand shaking
• D. Living together in the same room

Explanation: The correct answer is Blood transfusion with contaminated blood because HIV is primarily transmitted through blood, sexual contact, and from mother to child during childbirth or breastfeeding. Blood transfusions with infected blood can lead to transmission, making this option valid. On the other hand, Unhygienic living conditions does not increase the risk of HIV transmission as the virus is not spread through environmental factors or hygiene. Hand shaking is also incorrect, as HIV cannot be transmitted through casual contact. Finally, Living together in the same room does not pose a risk for HIV transmission, as it requires specific bodily fluids for the virus to spread.

Q84. Crossing over involves exchange of genetic material between:

• A. Sister chromatids of same chromosome
• B. Non-sister chromatids of homologous chromosomes✓
• C. Chromatids of non-homologous chromosomes
• D. Sister chromatids of homologous chromosomes

Explanation: Crossing over is a critical process during meiosis where non-sister chromatids of homologous chromosomes exchange genetic material. This exchange increases genetic diversity among gametes. The correct answer is Option B because it accurately describes the participants in crossing over. Options A, C, and D are incorrect as they involve either sister chromatids or non-homologous chromosomes, which do not participate in this process.

Q85. B-lymphocytes are formed and matured in:

• A. Liver
• B. Spleen
• C. Bone marrow✓
• D. Thymus

Explanation: B-lymphocytes, also known as B cells, are a type of white blood cell crucial for the immune system, specifically for antibody production. They are formed and mature in the bone marrow, where they undergo a series of developmental stages before entering circulation to help defend the body against pathogens. The liver and spleen, while important in other aspects of immune function, do not play a direct role in the formation or maturation of B-lymphocytes. The thymus is specifically involved in the maturation of T-lymphocytes, which are another type of immune cell.

Q86. Which phenomenon increases the chances of variations?

• A. Crossing Over✓
• B. Linkage
• C. Epistasis
• D. Dominance

Explanation: The correct answer is Crossing Over because it enhances genetic variation by allowing the recombination of alleles during meiosis. This process results in offspring that have different combinations of genes than their parents, thereby increasing genetic diversity within a population. In contrast, Linkage can restrict variation by keeping certain alleles together, Epistasis influences the expression of traits rather than creating new variations, and Dominance describes the relationship between alleles without increasing genetic diversity.

Q87. When antibodies produced by B-cells kill the antigens then it is called:

• A. Cell mediated response
• B. Passive response
• C. Humoral response✓
• D. Cells collaborated response

Explanation: When antibodies produced by B-cells bind to and neutralize antigens, this process is known as the humoral immune response. This response is crucial for identifying and eliminating pathogens in bodily fluids. In contrast, the cell-mediated response involves T-cells and does not primarily utilize antibodies; instead, it targets infected cells directly. The term passive response refers to immunity that is acquired rather than actively produced by the organism itself, such as maternal antibodies transferred to an infant. Finally, 'cells collaborated response' is not a recognized term in immunology, making it an incorrect choice. Therefore, the correct answer is the humoral response, where B-cells play a central role in antibody production.

Q88. Automatic and rapid actions that do not involve the conscious part of brain is:

• A. Reflex actions✓
• B. Conditioned reflexes
• C. Taxes
• D. Synapses

Explanation: The correct answer is reflex actions. Reflex actions are automatic responses to stimuli that occur without the involvement of the conscious part of the brain. For example, when you touch something hot, your hand instinctively withdraws due to a reflex. This process involves sensory neurons activating motor neurons through the spinal cord, allowing for rapid responses to protect the body. Option B, conditioned reflexes, refers to learned behaviors that develop over time through conditioning, which involves conscious thought at some stage. Option C, taxes, is unrelated to the biological functions of the nervous system and is a concept from economics. Option D, synapses, while crucial for neural communication, do not represent an action but rather a structural component of the nervous system.

Q89. The regulator of muscle contraction, which is released from sarcoplasmic reticulum, is:

• A. Tropomyosin
• B. Troponin
• C. Calcium ions✓
• D. ATP

Explanation: The correct answer is calcium ions because they are the key regulators of muscle contraction. When an action potential reaches the muscle fiber, calcium ions are released from the sarcoplasmic reticulum into the cytoplasm. These calcium ions bind to the troponin complex, causing a conformational change that moves tropomyosin away from the actin binding sites, allowing myosin to bind to actin and initiate contraction.Other options are incorrect: tropomyosin and troponin are proteins involved in the contraction process but do not act as regulators themselves; rather, they respond to the presence of calcium ions. ATP is crucial for muscle contraction as it provides energy for the myosin heads to perform the power stroke, but it does not regulate the contraction mechanism directly.

Q90. Role of mRNA in COVID-19 vaccines like Pfizer and Moderna is to:

• A. Helps the immune system recognize the virus
• B. Instructs cells to produce the viral spike protein✓
• C. Triggers immediate antibody release from memory cells
• D. Delivers enzymes that destroy the virus

Explanation: The correct answer is that the mRNA in COVID-19 vaccines like Pfizer and Moderna instructs cells to produce the viral spike protein. This spike protein is a harmless piece of the virus that stimulates the immune system to recognize and fight the actual virus if encountered in the future. Option A, while related to immune response, does not accurately describe the specific role of mRNA. Option C is incorrect because mRNA does not directly trigger the release of antibodies from memory cells; it first needs to be translated into a protein. Option D is also incorrect since mRNA vaccines do not involve the delivery of enzymes that destroy the virus, but rather they use the body's own cellular machinery to produce the viral protein.

Q91. Living cells of cartilage are called as:

• A. Osteocytes
• B. Thrombocytes
• C. Chondrocytes✓
• D. Osteoblasts

Explanation: The correct answer is Chondrocytes because these are the living cells found in cartilage tissue, responsible for producing and maintaining the cartilaginous matrix. They are crucial for the growth and repair of cartilage.Other options are incorrect for the following reasons:Osteocytes: These are mature bone cells, not related to cartilage.Thrombocytes: These are blood platelets involved in clotting and have no role in cartilage.Osteoblasts: These are bone-forming cells, and thus do not pertain to cartilage.

Q92. Correct order of bond energy will be

• A. HCl>HBr>HI✓
• B. HBr>HCl>HI
• C. HI>HCl>HBr
• D. HCl>HI>HBr

Explanation: The correct order of bond energy is HCl>HBr>HI. This is due to the fact that HCl has a shorter bond length than both HBr and HI, resulting in a stronger bond and higher bond energy. HBr has a longer bond length than HCl but is still shorter than that of HI, leading to intermediate bond energy. Finally, HI has the longest bond length, which results in the lowest bond energy. Therefore, options B, C, and D are incorrect as they misrepresent the bond energies based on the bond lengths of these hydrogen halides.

Q93. IUPAC name of the compound is CH3(CH2)4CH(CH3)2:

• A. 2-methylheptane✓
• B. 3-methylheptane
• C. 4-methylheptane
• D. Octane

Explanation: The compound CH3(CH2)4CH(CH3)2 has a total of 7 carbon atoms in the longest chain, classifying it as a heptane. The substituent, a methyl group (CH3), is located on the second carbon of the chain, giving it the name 2-methylheptane. The other options are incorrect because they misplace the methyl group or incorrectly identify the number of carbon atoms in the main chain.

Q94. IUPAC name of the compound C2H5CH=C(C3H) C2H5 is:

• A. 1,2-diethyl-2-propylethene
• B. 3-ethylhept-3-ene
• C. 4-ethylhept-3-ene✓
• D. 4-ethylhept-2-ene

Explanation: The correct IUPAC name for the compound C2H5CH=C(C3H)C2H5 is 4-ethylhept-3-ene. This is derived from identifying the longest chain of carbon atoms, which has seven carbons (heptane), with a double bond located at the third carbon. The '4-ethyl' indicates that there is an ethyl group attached to the fourth carbon of the heptane chain. Option A (1,2-diethyl-2-propylethene) is incorrect as it misidentifies the structure by suggesting multiple ethyl groups and misplacing the double bond. Option B (3-ethylhept-3-ene) incorrectly places the ethyl group and double bond. Option D (4-ethylhept-2-ene) misplaces the double bond at the second carbon instead of the third. Thus, option C is the only correct choice.

Q95. Among the following compound, the most susceptible to nucleophilic attack ont carbonyl carbon is:

• A. CH3COCl✓
• B. CH3CHO
• C. CH3COOCH3
• D. CH3COOCOCH3

Explanation: The correct answer is CH3COCl because the presence of the chlorine atom enhances the electrophilicity of the carbonyl carbon, making it more susceptible to nucleophilic attack. In contrast, CH3CHO (an aldehyde) is less reactive due to the lack of a strong leaving group. CH3COOCH3 (an ester) has electron-donating alkoxy substituents that stabilize the carbonyl carbon, while CH3COOCOCH3 (an anhydride) is hindered by steric effects, leading to lower reactivity compared to the acyl chloride.

Q96. Which of the following is expected to be the most paramagnetic?

• A. 3Li
• B. 4Be
• C. 5B✓
• D. 6C

Explanation: The correct answer is 5B, as it has three unpaired electrons in its 2p orbital, which contributes to its paramagnetism. In contrast, 3Li has one unpaired electron, making it weakly paramagnetic, while 4Be has no unpaired electrons and is thus diamagnetic. Lastly, 6C has two unpaired electrons, which makes it less paramagnetic compared to boron. Therefore, 5B is the most paramagnetic among the given options.

Q97. The formation of activated complex in a reaction is:

• A. Exothermic process
• B. Endothermic process✓
• C. Either endo or exo
• D. Always energy released

Explanation: The correct answer is Option B: Endothermic process. The formation of an activated complex requires energy input to break bonds in the reactants and form new interactions, representing a high-energy transition state. In contrast, Option A is incorrect because it suggests energy release, which is not characteristic of the activated complex formation. Option C is misleading, as it implies that both energy release and absorption can occur, while in reality, the formation of the activated complex is predominantly endothermic. Finally, Option D is incorrect as it states that energy is always released, which does not align with the fundamental nature of the activated complex.

Q98. The maximum probability of finding an electron is at a distance of

• A. 0.53 nm
• B. 0.35 nm
• C. 0.053 nm✓
• D. 0.0053 nm

Explanation: The maximum probability of finding an electron is determined by its wave function, particularly in the case of a hydrogen atom, where the most probable distance from the nucleus is at approximately 0.053 nm. This distance relates to the 1s orbital, where the electron density is highest. The other options, while they represent distances relevant to atomic structure, do not correspond to the maximum probability of locating an electron as defined by quantum mechanics. Option A (0.53 nm) and Option B (0.35 nm) are larger than the most probable distance, while Option D (0.0053 nm) is unrealistically small for typical atomic structures.

Q99. The IUPAC name of Vinyl acetylene is:

• A. But-1-en-3-yne✓
• B. But-3-en-1-yne
• C. Pent-3-en-I-yne
• D. Pent-2-en-4-yne

Explanation: The correct answer is But-1-en-3-yne. Vinyl acetylene consists of 4 carbon atoms with a double bond between the first and second carbons and a triple bond between the second and third carbons. Therefore, the longest chain, which includes both the double and triple bonds, is correctly named as But-1-en-3-yne. The other options are incorrect due to either incorrect carbon count or misplacement of the multiple bonds, which do not accurately reflect the structure of vinyl acetylene.

Q100. Which atom has at least single electron in dumbell shape orbital?

• A. H
• B. He
• C. Li
• D. B✓

Explanation: Boron (B) is the first element to have an electron in a dumbbell-shaped p orbital. The 2p orbitals start to fill at this point in the periodic table, and since boron has five electrons, it has one electron in the 2p orbital. In contrast, hydrogen and helium only have electrons in the 1s orbital, which is spherical, while lithium has a 2s electron but no 2p electrons. Thus, the correct answer is B.

Q101. Which of following adhesive is used to bond broken pieces of jewelry?

• A. Super glue✓
• B. Epoxy resin
• C. Silicon resin
• D. Starch

Explanation: The correct answer is Super glue because it is specifically formulated to create strong and quick bonds, making it highly effective for repairing broken jewelry pieces. In contrast, while epoxy resin is also a strong adhesive, it requires a mixing process and longer curing time, which might not be convenient for quick repairs. Silicon resin lacks the necessary bonding strength for metal jewelry, and starch is not an adhesive suitable for this purpose, as it does not provide any significant bonding capability.

Q102. Ratio of sigma bonds and pi bonds present in benzene are:

• A. 4:1✓
• B. 1:4
• C. 2:3
• D. 6:1

Explanation: The correct answer is the ratio of sigma bonds to pi bonds in benzene, which is 4:1. Benzene consists of 6 carbon atoms and forms 6 sigma bonds with hydrogen atoms and 3 pi bonds due to its resonance structure. Therefore, the total number of sigma bonds (4, considering the carbon-carbon bonds as single bonds in one resonance form) compared to pi bonds (3) results in a ratio of 4:1. The other options are incorrect as they misrepresent the bonding structure of benzene, failing to account for the correct number of sigma and pi bonds present in its molecular structure.

Q103. Which one is addition polymer?

• A. polyvinyl chloride✓
• B. nylon 6,6
• C. nylon 6,10
• D. polyester

Explanation: Polyvinyl chloride (PVC) is the correct answer because it is an addition polymer formed through the polymerization of vinyl chloride monomers without the loss of any small molecules. In contrast, nylon 6,6 and nylon 6,10 are both condensation polymers, as they are created through condensation reactions that release water during the process. Polyester is similarly a condensation polymer, formed from the reaction of diols and dicarboxylic acids, also releasing small molecules. Therefore, the only addition polymer in this list is polyvinyl chloride.

Q104. When one mole of a substance is decomposed preferably as comparod to evaporation then decomposition has:

• A. Low energy✓
• B. High energy
• C. Equal energy
• D. Cannot be predicted

Explanation: The correct answer is Low energy because decomposition reactions often require less energy compared to evaporation processes that involve breaking intermolecular forces in a liquid. In evaporation, molecules must gain enough energy to transition from a liquid state to a gaseous state, which typically requires higher energy input. In contrast, decomposition may involve breaking chemical bonds, but it is often less energy-intensive overall than the energy needed for complete evaporation. The other options are incorrect as they either overestimate the energy required for decomposition (High energy), suggest an equivalency that doesn't hold (Equal energy), or imply unpredictability in a process that can be analyzed through stoichiometric principles (Cannot be predicted).

Q105. At start of reaction:

• A. Average rate is high
• B. Instantaneous rate is high✓
• C. Both rates are same
• D. Both rates are slow

Explanation: At the start of a reaction, the concentration of reactants is at its maximum, which usually results in a high instantaneous rate of reaction. The instantaneous rate reflects the speed of the reaction at a given moment, while the average rate is calculated over a period of time and may not capture the initial rapid changes. Therefore, option B is correct. Options A and C incorrectly suggest low or equal rates at the start, and option D misrepresents the behavior of the reaction kinetics, as both rates would not be slow at this point.

Q106. During Clemmenson reduction of aldehyde and ketone, carbonyl group into alkane roup is carried out with:

• A. H2 and Pd
• B. LiAlH4
• C. Zn/Hg conc.HCl✓
• D. NH2-NH3KOH

Explanation: The Clemmensen reduction is a chemical reaction that converts aldehydes and ketones into alkanes using zinc amalgam and concentrated hydrochloric acid (Zn/Hg conc.HCl). This method is particularly useful because it avoids the use of strong nucleophiles that can alter the structure of sensitive molecules. The other options are incorrect because: 1) H2 and Pd refers to hydrogenation, which is not specific to carbonyl reduction; 2) LiAlH4 is a strong reducing agent for alcohol formation; and 3) NH2-NH3KOH corresponds to the Wolff-Kishner reduction, another method of reducing carbonyls that does not involve the Clemmensen conditions.

Q107. Consider the given reactionN2+ 3H2 --- 2NH3If 56g of N reacts with 12 g of H and produces 51g of NH3, what is the theoretical yield (TY)of NH3 and the percentage yield (PY) of the reaction?(Molar mass of N2 = 28.g/mol, H2= 2 g/mol and NH3= 17 g/mol)

• A. TY = 68 g and PY = 75%✓
• B. TY = 34 g and PY = 67%
• C. TY = 68 g and PY = 33%
• D. TY = 34 g and PY = 75%

Explanation: To find the theoretical yield of NH3, we first need to determine the limiting reactant. The balanced equation indicates that 1 mole of N2 reacts with 3 moles of H2 to produce 2 moles of NH3. Given the molar masses, we convert grams to moles: 56 g of N2 is 2 moles, and 12 g of H2 is 6 moles. Since we have enough H2 to react with the available N2, nitrogen is the limiting reagent. From the stoichiometry, 2 moles of N2 yield 4 moles of NH3. Converting moles of NH3 to grams gives 68 g. The actual yield is 51 g, thus the percentage yield is (51 g / 68 g) * 100% = 75%. Options B, C, and D miscalculate either the theoretical yield or the percentage yield.

Q108. When SHE is connected with Cu electrode using salt bridge and external wire:

• A. Cu reduces
• B. Cu+2 reduces✓
• C. H- reduces
• D. H2 reduces

Explanation: In the setup described, the Standard Hydrogen Electrode (SHE) is connected to a copper (Cu) electrode. In this electrochemical cell, the copper ions (Cu+2) in solution are reduced at the copper electrode by gaining electrons. Therefore, the correct answer is that Cu+2 reduces to form solid copper (Cu). Option A is incorrect because it does not specify the ionic state of copper involved in the reaction. Option C is wrong as H- does not exist in this context; it is the H+ ions that would interact. Option D is also incorrect because it suggests that H2 is being reduced, while in fact, H2 acts as a reducing agent by donating electrons, thus being oxidized instead.

Q109. The ionic compound among the following with the highest lattice energy is

• A. LiF✓
• B. NaCl
• C. KCl
• D. CsI

Explanation: The correct answer is LiF, which has the highest lattice energy among the options provided. Lattice energy is influenced by both the charge of the ions and their sizes. LiF consists of small ions (Li+ with a +1 charge and F- with a -1 charge), leading to a strong electrostatic attraction and thus higher lattice energy.In contrast, NaCl has larger ions (Na+ and Cl-), resulting in a weaker attraction than LiF. Similarly, KCl has even larger ions, further reducing its lattice energy. CsI, with the largest ions among the options, exhibits the lowest lattice energy due to the significantly weaker attraction between its ions.

Q110. Digestion of protein started when food enters in:

• A. Mouth
• B. Stomach✓
• C. Intestine
• D. Epiglottis

Explanation: The correct answer is Stomach because this is where the digestion of proteins begins. The stomach's acidic environment denatures proteins and activates the enzyme pepsin, which starts breaking them down into smaller peptides.Option A, Mouth, is incorrect because while food is chewed and mixed with saliva, protein digestion does not begin until the stomach. Option C, Intestine, is also incorrect as the small intestine is primarily responsible for further digestion and absorption of nutrients after the stomach has initiated the breakdown. Finally, Option D, Epiglottis, is incorrect since it does not participate in the digestion process at all, but rather in protecting the airway during swallowing.

Q111. Which compound will not show geometrical isomerism?

• A. But-2-ene
• B. 1,2-dimethylcyclopropane
• C. Pent-1-ene✓
• D. 1,3-dimethylcyclopentane

Explanation: The correct answer is Pent-1-ene because it does not have the structural features necessary for geometrical isomerism. Geometrical isomerism typically arises in compounds with double bonds or rings where substituents can be arranged differently in space. But-2-ene and 1,2-dimethylcyclopropane both have structural characteristics that allow for different configurations (cis/trans) or spatial arrangements, thus exhibiting geometrical isomerism. Similarly, 1,3-dimethylcyclopentane can exhibit some isomerism, but it does not involve a double bond that would lead to the formation of geometrical isomers.

Q112. Which of the following is least volatile?

• A. Glycerol✓
• B. Water
• C. Acetic acid
• D. Diethyl ether

Explanation: The correct answer is Glycerol, which is the least volatile among the listed substances due to its high molecular weight and strong hydrogen bonding capabilities. These factors make it less likely to evaporate compared to the other options. Water has moderate volatility, acetic acid is more volatile than glycerol due to its lower molecular weight, and diethyl ether is highly volatile with a low boiling point, making it evaporate rapidly. Therefore, Glycerol is the least volatile substance in this group.

Q113. All of following have two bond pairs and show linear geometry except:

• A. SnCl2✓
• B. CS2
• C. HCN
• D. CO2

Explanation: The correct answer is SnCl2, which is the only molecule among the options provided that deviates from the linear geometry. SnCl2 features a lone pair on the central atom, tin, resulting in a bent shape rather than linear. In contrast, CS2, HCN, and CO2 all have two bond pairs and no lone pairs, leading to a linear geometry as they maintain sp hybridization and do not exhibit any repulsion from lone pairs. Thus, they conform to the description of having linear geometry.

Q114. Which of the following molecules have símilar molecular shape?

• A. NH3 & AlCl3
• B. BCl3 & NH3
• C. AlCl3 and PCl3
• D. H2O & SnCl2✓

Explanation: The correct answer is Option D: H2O & SnCl2 because both of these molecules exhibit a bent shape. In H2O, the oxygen atom is sp3 hybridized, leading to a bent shape due to the presence of two lone pairs. Similarly, SnCl2 also has a central tin atom that is sp3 hybridized with one lone pair, resulting in a bent shape as well.On the other hand, Option A (NH3 & AlCl3) has different shapes, with NH3 being trigonal pyramidal and AlCl3 being trigonal planar. Option B (BCl3 & NH3) also presents different shapes, as BCl3 is trigonal planar while NH3 is trigonal pyramidal. Lastly, Option C (AlCl3 & PCl3) features different shapes as well, with AlCl3 being trigonal planar and PCl3 being trigonal pyramidal. Thus, only Option D correctly identifies molecules with similar molecular shapes.

Q115. Valuc of electronegativity of atoms A and B are 1.20 and 4.0 respectively, the percent ionic character wvill be:

• A. 43%
• B. 50%
• C. 55%
• D. 73%✓

Explanation: To determine the percent ionic character of the bond between atoms A and B, we can use the formula: Percent Ionic Character = 100 * (1 - e^(-0.25 * (ElectronegativityA - ElectronegativityB)^2))Substituting the values, we have:ElectronegativityA = 1.20, ElectronegativityB = 4.0Difference = 4.0 - 1.20 = 2.80Using the formula gives us a percent ionic character of approximately 73%. This reflects a strong ionic bond due to the large difference in electronegativity. The other options (43%, 50%, 55%) underestimate the ionic character given the significant electronegativity difference, which is crucial in establishing the bond type.

Q116. Phenol differs from ethanol because it:

• A. Forms stronger hydrogen bonds to its aromatic ring
• B. Is more acidic because of resonance stabilized conjugate base✓
• C. Readily undergoes nucleophilic substitution at the -OH group
• D. Is completely insoluble in water due to its benzene ring

Explanation: The correct answer is Option B: Phenol is more acidic than ethanol because of the resonance stabilization of its conjugate base, the phenoxide ion, which allows it to better stabilize the negative charge after deprotonation. In contrast, ethanol does not benefit from such resonance stabilization when it loses a proton.Option A is incorrect as the strength of hydrogen bonds formed by phenol is not primarily due to its aromatic nature. Option C is misleading because phenol does not undergo nucleophilic substitution; instead, it engages in electrophilic substitution due to the stability of the aromatic system. Lastly, Option D is false as phenol is soluble in water due to its -OH group, which can interact favorably with water molecules, despite the hydrophobic character of the benzene ring.

Q117. WIhich reagent and condition are used to bring about the reaction shown?Toluene →p-chloro toluene

• A. Cl2 in the dark
• B. Cl2 in the presence of AlCl3✓
• C. Cl2 in the presence of UV light
• D. Concentrated HCl heated under reflux

Explanation: The correct answer is Option B: Cl2 in the presence of AlCl3. In this reaction, aluminum chloride serves as a Lewis acid catalyst, facilitating the electrophilic aromatic substitution of toluene to form p-chloro toluene. The chlorine molecule becomes activated in the presence of the AlCl3, allowing it to effectively substitute a hydrogen atom on the aromatic ring of toluene, preferably at the para position due to steric factors. Option A (Cl2 in the dark) is incorrect as it lacks the necessary catalyst for the reaction to proceed. Option C (Cl2 in the presence of UV light) is misleading, as UV light typically induces free radical reactions, which are not suitable for aromatic substitution. Option D (Concentrated HCl heated under reflux) does not provide the correct electrophilic conditions needed for aromatic halogenation and is therefore incorrect.

Q118. What is 50% yield when actual yield and theoretical yield are 2g and 4g respectively?

• A. 25%
• B. 50%✓
• C. 75%
• D. 85%

Explanation: The percentage yield is calculated using the formula: Percentage Yield = (Actual Yield / Theoretical Yield) × 100. In this case, the actual yield is 2g and the theoretical yield is 4g. Plugging in these values gives: (2g / 4g) × 100 = 50%. Therefore, the correct answer is 50%. The other options are incorrect as they do not reflect the actual yield in relation to the theoretical yield given in the question.

Q119. IUPAC name of CHCCl is

• A. Chloroethane
• B. Chloroethyne✓
• C. Chloroethene
• D. Ethyl chloride

Explanation: The correct IUPAC name for CHCCl is Chloroethyne because it is an alkyne with a triple bond between the two carbon atoms (C≡C) and a chlorine atom substituent. The structure CHCCl indicates that there is one carbon atom bonded to another carbon atom with a triple bond, along with a chlorine atom attached to one of the carbons. The other options are incorrect for the following reasons:Chloroethane: This suggests a saturated compound with a single bond, which does not match the structure.Chloroethene: This indicates an alkene with a double bond, which is not applicable here.Ethyl chloride: This is a common name that does not conform to IUPAC naming conventions for the specific structure provided.

Q120. The order of reactivity of following R-X for SN2 reaction is

• A. RF>RCl>RBr>RI✓
• B. RBr>RF>RCl>RI
• C. RCl>RF>RBr>RI
• D. RF>RBr>RCl>RF

Explanation: The correct order of reactivity for SN2 reactions for alkyl halides is influenced primarily by the bond strength between carbon and the halogen. The C-F bond is the strongest, making RF the least reactive in SN2 reactions. The correct order, therefore, is RF > RCl > RBr > RI. In the other options, RBr and RCl are incorrectly positioned relative to RF, and incorrect bonding strengths are suggested, which is why they are wrong.

Q121. Which is not true about benzene:

• A. Sp2 hybridization
• B. Fractional bond order
• C. No elimination reaction
• D. 6 sites for monosubstitution✓

Explanation: The correct answer is D: 6 sites for monosubstitution. Benzene has a symmetrical structure, which means it has only one unique site for monosubstitution due to the equivalence of its carbon atoms in the ring. This leads to the misconception that there are six distinct sites when, in reality, substituents can be placed at any of the six positions without altering the molecule's structure due to symmetry.Option A is incorrect because benzene does indeed have sp2 hybridization, leading to its planar structure. Option B is also incorrect; benzene displays fractional bond order due to resonance, which averages the bond character among the carbon-carbon bonds. Option C is misleading; while benzene does not favor elimination reactions, it can participate in some under specific conditions, though substitution is far more common.

Q122. If ionization energy of an element is greater then:

• A. More is its reducing power
• B. More is its electropositivity
• C. Less is its metallic character✓
• D. More is its atomic radius

Explanation: The correct answer is that if the ionization energy of an element is greater, then its metallic character is less. This is because a higher ionization energy indicates that the element holds onto its electrons more tightly, making it less likely to exhibit metallic properties, which are characterized by a readiness to lose electrons. Option A is incorrect because a greater ionization energy means reduced reducing power, as reducing agents tend to have lower ionization energies. Option B is also incorrect since greater ionization energy implies lower electropositivity; highly electropositive elements have low ionization energies. Option D is incorrect because a greater ionization energy typically corresponds with a smaller atomic radius due to the stronger attraction between the nucleus and the electrons.

Q123. The mass of hydrogen gas needed to produce 51g ammonia:

• A. 6 g
• B. 9 g✓
• C. 12 g
• D. 15 g

Explanation: To find the mass of hydrogen gas needed to produce 51 g of ammonia (NH3), we first need to consider the balanced chemical equation: 3 H2 + N2 → 2 NH3 From the equation, 3 moles of hydrogen (H2) produce 2 moles of ammonia (NH3). We can calculate the molar mass of ammonia as follows: NH3 has a molar mass of approximately 17 g/mol. Therefore, 51 g of NH3 is equivalent to: 51 g NH3 × (1 mol NH3 / 17 g NH3) = 3 mol NH3 Using the stoichiometric ratio from the balanced equation, we see that 3 moles of NH3 require 4.5 moles of H2 (from the ratio 3:2). The molar mass of hydrogen gas (H2) is approximately 2 g/mol, so: 4.5 moles H2 × 2 g/mol = 9 g H2 Thus, the correct answer is 9 g (Option B). The other options are incorrect because they either underestimate or overestimate the required mass of hydrogen based on stoichiometric calculations.

Q124. Select the standard condition for temperature and pressure:

• A. 1 atm and 0 K
• B. 760 torr and 25°C
• C. 2 bar and 25°C
• D. 14.7 psi and 0℃✓

Explanation: The correct answer is option D: 14.7 psi and 0℃. Standard temperature and pressure (STP) are defined as 0 degrees Celsius (0℃) and 1 atmosphere (atm), which is equivalent to 14.7 pounds per square inch (psi). This is commonly used in scientific calculations involving gases.Option A is incorrect because, while 1 atm is correct, 0 K (absolute zero) is not a practical temperature for STP; instead, it should be 0°C. Option B is incorrect because, although 760 torr corresponds to 1 atm, the temperature of 25°C is not the standard temperature for STP, which should be 0°C. Option C is also incorrect as 2 bar is higher than the standard pressure of 1 atm, and the temperature of 25°C is not standard for STP.

Q125. Which of the following is NOT a state function?

• A. Enthalpy
• B. Work✓
• C. Internal energy
• D. Pressure

Explanation: The correct answer is Work, as it is not a state function. State functions are properties that depend only on the state of the system and not on the path taken to reach that state. Enthalpy, internal energy, and pressure are all state functions, as they are determined solely by the current conditions of the system. In contrast, work varies based on the process and path taken, making it path-dependent rather than state-dependent.

Q126. Which one is not a type of stereoisomerism?

• A. Conformational isomerism
• B. Optical isomerism
• C. Geometrical isomerism
• D. Metamerism✓

Explanation: The correct answer is Metamerism, which is not a type of stereoisomerism. Instead, it is considered a form of structural isomerism, where compounds share the same molecular formula but have different structural frameworks. In contrast, Conformational isomerism, Optical isomerism, and Geometrical isomerism all involve spatial arrangements of atoms and are categorized as stereoisomers. Conformational isomers can change shape through rotation around single bonds, optical isomers are non-superimposable mirror images, and geometrical isomers differ in the spatial arrangement of groups around a double bond or within a ring.

Q127. Formic acid reacts with ethanol in presence of acid catalyst producing:

• A. Ester✓
• B. Ether
• C. Acid anhydride
• D. Phenol

Explanation: In this reaction, formic acid (HCOOH) reacts with ethanol (C2H5OH) in the presence of an acid catalyst such as sulfuric acid. This process is known as esterification, where a water molecule is eliminated, resulting in the formation of an ester. The specific ester formed from this reaction is ethyl formate (HCOOC2H5). The other options are incorrect because they do not represent the products formed through this specific reaction mechanism.

Q128. K is called specific rate constant because it is:

• A. Rate per unit concentration✓
• B. Temperature independent
• C. Depends on concentration
• D. Unitless

Explanation: The correct answer is that the specific rate constant (K) is defined as the rate per unit concentration. It quantifies the speed of a chemical reaction and is essential in expressing the relationship between concentration and reaction rate. The specific rate constant is specific to a particular reaction and temperature. Option B is incorrect because K is dependent on temperature; it changes with variations in temperature. Option C suggests that K depends on concentration, which is misleading since K itself is a constant for a given reaction at a specific temperature, independent of the concentrations of the reactants. Finally, Option D is incorrect because K does have units, which vary depending on the order of the reaction.

Q129. Number of sigma bonds in methyl chloride is due to sp3-s overlap is/are:

• A. 1
• B. 2
• C. 3
• D. 4✓

Explanation: Methyl chloride (CH3Cl) consists of a carbon atom bonded to three hydrogen atoms and one chlorine atom. The carbon atom undergoes sp3 hybridization, resulting in four sp3 hybrid orbitals. Each of these orbitals overlaps with the s orbitals of hydrogen atoms and the p orbital of chlorine to form sigma bonds. Specifically, there are:3 C-H sigma bonds (one for each hydrogen)1 C-Cl sigma bond (with chlorine)Thus, the total number of sigma bonds is 4. The other options are incorrect as they underestimate the number of bonds formed in methyl chloride.

Q130. When pressure is 1520 torr then density of oxygen gas will be:

• A. 64/RT✓
• B. 32/RT
• C. 16/RT
• D. 128/RT

Explanation: The correct answer is Option A: 64/RT. To find the density of a gas, we can use the ideal gas equation: P = (density) * R * T. Rearranging this gives density = P/(RT). For oxygen (O2), the molecular weight is 32 g/mol, and at the given pressure of 1520 torr, the density can be derived as follows:Density = (Molecular Weight) * (Pressure in atm) / (R * T) = 32 g/mol * (1520 torr / 760 torr/atm) / (R * T) = 64/RT.Options B, C, and D are incorrect because they do not represent the correct molecular weight of oxygen gas under the specified conditions. Option B suggests a density that is too low, while Options C and D suggest densities that are not supported by the molecular weight of oxygen gas.

Q131. Which equation is used to calculate concentration for n mole of an ideal gas?

• A. PV/RT✓
• B. P/RT
• C. PCM/RT
• D. PM/RT

Explanation: The correct answer is PV/RT, which directly calculates the concentration of an ideal gas using the ideal gas law. In this equation, concentration (C) can be derived as the ratio of pressure (P) multiplied by volume (V) divided by the product of the ideal gas constant (R) and temperature (T). The other options are incorrect because:P/RT lacks the volume term, rendering it insufficient for concentration calculation.PCM/RT is not a recognized equation in the context of gases, as it introduces an undefined variable.PM/RT computes pressure but does not yield concentration directly, as it doesn't include volume in the calculation.

Q132. Which carbonyl carbon is more electrophilic

• A. HCOOH
• B. HCHO✓
• C. CH3COCH3
• D. CH3COOH

Explanation: The correct answer is HCHO (formaldehyde) because it is an aldehyde with a highly electrophilic carbonyl carbon. Aldehydes are generally more electrophilic than ketones because they have fewer electron-donating groups attached to the carbonyl carbon, which allows for greater reactivity towards nucleophiles. In contrast, the other options are less electrophilic due to the presence of electron-donating groups or additional steric hindrance:HCOOH (formic acid): Although it has a carbonyl group, the -OH group decreases its electrophilicity.CH3COCH3 (acetone): As a ketone, it has two methyl groups that donate electron density, reducing electrophilicity.CH3COOH (acetic acid): The carbonyl is adjacent to a hydroxyl group, which also donates electron density, further decreasing electrophilicity.

Q133. 50g of Mg is burnt with 32g of oxygen to form MgO, amount of excess reagent left is?

• A. 6g Mg
• B. 2g Mg✓
• C. 8g O2
• D. 16g O2

Explanation: To determine the amount of excess reagent left, we first need to identify the limiting reagent. The balanced chemical equation for the reaction between magnesium (Mg) and oxygen (O2) to form magnesium oxide (MgO) is: 2 Mg + O2 → 2 MgO This indicates that 2 moles of magnesium react with 1 mole of oxygen. The molar mass of magnesium is approximately 24g/mol, and that of oxygen is 32g/mol. From the data provided: - Moles of Mg = 50g / 24g/mol ≈ 2.08 moles - Moles of O2 = 32g / 32g/mol = 1 mole According to the stoichiometry of the reaction, 2.08 moles of Mg would require 1.04 moles of O2 to react completely, but we only have 1 mole of O2. Thus, oxygen is the limiting reagent, and magnesium is in excess. To find the amount of Mg that reacts, we use the available 1 mole of O2: it will react with 2 moles of Mg. Since we only have 1 mole of O2, it will react with 2 moles of Mg, meaning: 2 moles of Mg = 48g of Mg. Thus, from the original 50g of magnesium, 50g - 48g = 2g of excess magnesium remains unreacted. Therefore, the correct answer is 2g Mg. The other options are incorrect as they miscalculate the amounts of the reactants or do not follow the stoichiometric ratios.

Q134. The heat of formation of CO and CO2 are -26.4 Kcal and -94.0 Kcal respectively. The heat of combustion of carbon monoxide according to Hess's Law will be:

• A. +26.4 Kcal
• B. -67.6 Kcal✓
• C. +94.0 Kcal
• D. -120.4 Kcal

Explanation: To find the heat of combustion of carbon monoxide (CO), we can apply Hess's Law. The heat of formation of CO is -26.4 Kcal, and the heat of formation of CO2 is -94.0 Kcal. The combustion of CO can be represented as: 2 CO + O2 → 2 CO2. To find the heat of combustion, we can use the equation: ΔHcomb = ΣΔHf (products) - ΣΔHf (reactants). Calculating this gives: ΔHcomb = [2(-94.0 Kcal)] - [2(-26.4 Kcal)] = -188.0 Kcal + 52.8 Kcal = -135.2 Kcal for two moles of CO. Dividing by 2 to find the heat for one mole gives -67.6 Kcal. Therefore, the correct answer is -67.6 Kcal. The other options are incorrect because they either misinterpret the direction of energy transfer or do not accurately apply Hess's Law.

Q135. Rate of dehydration of alcohol is

• A. 3°>2°>1°✓
• B. 1°>3°>2°
• C. 2°>3°>1°
• D. 3°>1°>2°

Explanation: The correct answer is Option A (3°>2°>1°). Tertiary alcohols dehydrate faster than secondary alcohols, which in turn dehydrate faster than primary alcohols. This trend is due to the stability of the carbocations formed during the dehydration process. Tertiary carbocations are stabilized by the electron-donating effects of surrounding alkyl groups, making them more favorable for dehydration. In contrast, primary carbocations are highly unstable, resulting in a much slower dehydration rate. The other options incorrectly rank the dehydration rates of the different classes of alcohols, failing to account for the stability of the carbocations formed during the reaction.

Q136. During the drilling of a metal surface the drill bit heats up. This heat comes from the

• A. Vibration of the tool
• B. Work done against friction✓
• C. Flow of electric current
• D. Compression of air

Explanation: During the drilling process, as the drill bit penetrates the metal surface, it faces resistance which creates friction. This friction generates heat, causing the drill bit to heat up. The correct answer, work done against friction, highlights that the mechanical work required to penetrate the material leads to this heat generation. Other options, like vibration of the tool, flow of electric current, and compression of air, do not directly account for the primary source of heat in this scenario.

Q137. If 2J of work is done in moving two coulombs of charge from one point to the other in an electric field. The potential difference between the points is

• A. 1 J/C✓
• B. 2 J/C
• C. 2 JC
• D. 2 J/C

Explanation: The potential difference (V) between two points in an electric field is given by the formula V = W/Q, where W is the work done and Q is the charge moved. In this case, 2J of work is done to move 2 coulombs of charge, so:V = 2J / 2C = 1 J/C.This indicates that the correct answer is Option A (1 J/C). Other options are incorrect because they either miscalculate the potential difference or use incorrect units.

Q138. The motion of transverse waves involves particle's vibration

• A. Along the wave direction
• B. Opposition to energy flow
• C. Perpendicular to wave propagation✓
• D. In random direction at every point

Explanation: The correct answer is Option C: Perpendicular to wave propagation. In transverse waves, such as those seen in light or waves on a string, particles of the medium move up and down while the wave itself travels horizontally. This means that the motion of the particles is at a right angle to the direction of wave travel, which is characteristic of transverse wave motion.Option A is incorrect because it suggests that particles move in the same direction as the wave, which is a description of longitudinal waves instead. Option B is also incorrect as it implies that particle motion opposes wave energy, which is not true for transverse waves. Finally, Option D is incorrect because it suggests a random motion of particles, whereas transverse waves exhibit a specific and consistent motion relative to the wave direction.

Q139. A body moving in a circle, half revolution in terms of radians is equivalent

• A. π✓
• B. π/6
• C. π/2
• D. 2π

Explanation: A full revolution in a circle is equivalent to 2π radians. Therefore, half a revolution would be half of that: (1/2) * 2π = π. This means that when a body moves through half of a circular path, it covers an angular displacement of π radians. The other options represent different angular displacements that do not correspond to half a revolution.

Q140. If A = (a i + b j) and B = 4( a i - b j ), magnitude of A x B =

• A. 4 (a2 + b2)✓
• B. 4ab
• C. 8(a+b)
• D. 0

Explanation: To find the magnitude of the cross product |A x B|, we first need to calculate the vectors A and B. Given A = (a i + b j) and B = 4( a i - b j), we can find the components of each vector. The cross product A x B is computed as follows: A x B = |A||B| sin(θ), where θ is the angle between A and B. The magnitude of A is √(a² + b²) and the magnitude of B is |4|√(a² + b²) = 4√(a² + b²). Since A and B are not parallel, we know sin(θ) will not be zero. Thus, the magnitude of the cross product simplifies to 4(a² + b²), which corresponds to Option A. The other options do not properly represent the magnitude calculation or imply incorrect relationships between the vectors.

Q141. A proton and an alpha particle enter in the same magnitude with equal speeds, compared to proton, the alpha particle's path will have:

• A. Larger radius✓
• B. Smaller radius
• C. Smaller path length
• D. Greater deflection

Explanation: The correct answer is Larger radius because the alpha particle consists of two protons and two neutrons, giving it a greater mass and charge compared to a single proton. When both particles enter a magnetic field with the same speed, the radius of their curved paths is determined by the balance between the centripetal force and the magnetic Lorentz force. The greater mass of the alpha particle means it will experience less acceleration for the same magnetic force, resulting in a larger radius of curvature compared to the proton's path.In contrast, the other options are incorrect because:Smaller radius: This implies that the particle is deflected more sharply, which is not true for the alpha particle.Smaller path length: This does not apply here as path length is not directly determined by radius in this context.Greater deflection: This implies a sharper turn, which is not accurate given the alpha particle's larger mass leading to less deflection.

Q142. In circular motion, if angular displacement is kept constant, decreasing the radius will:

• A. Increase linear displacement
• B. Increase linear velocity
• C. Decrease linear displacement✓
• D. Not affect linear displacement

Explanation: In circular motion, angular displacement refers to the angle through which an object has rotated about a central point. The linear displacement (arc length) is directly related to both the angular displacement and the radius of the circle. Specifically, linear displacement can be calculated using the formula: linear displacement = radius × angular displacement. Therefore, if the angular displacement is kept constant and the radius is decreased, the linear displacement will also decrease because the arc length becomes shorter. Options A, B, and D are incorrect because they either suggest an increase in displacement or imply no change at all, which contradicts the established relationship between radius, angular displacement, and linear displacement.

Q143. When force and displacement are in opposite direction then the work done is said to be:

• A. Positive
• B. Negative✓
• C. Infinite
• D. Maximum

Explanation: When force and displacement are in opposite directions, the work done is classified as negative. This is because work is calculated as W = F × d × cos(θ), where θ is the angle between the force and displacement vectors. If the angle is 180 degrees (opposite directions), cos(180°) = -1, resulting in negative work. In contrast, positive work occurs when the force is in the same direction as the displacement, leading to an increase in the system's energy. Infinite work is not applicable in physics because work is constrained by the actual values of force and displacement. Additionally, maximum work would suggest an optimal scenario of energy transfer, which is not valid when the force opposes the displacement.

Q144. In a step-up transformer, if the secondary voltage is increased by a factor of 10, the current in secondary coil will be:

• A. 10 times higher than the primary current
• B. 10 times lower than the primary current
• C. Equal to the primary current
• D. One-tenth of the primary current✓

Explanation: In a step-up transformer, the relationship between primary and secondary voltage and current is governed by the equation: Vp / Vs = Is / Ip, where V represents voltage and I represents current for primary (p) and secondary (s) coils. When the secondary voltage is increased by a factor of 10, the equation indicates that the secondary current must decrease correspondingly to maintain energy conservation. Thus, if the voltage increases by a factor of 10, the current in the secondary coil must decrease to one-tenth of the primary current, which is represented by Option D. The other options are incorrect because they misinterpret the inverse relationship between voltage and current in a transformer. For example, saying the secondary current is 10 times higher or equal to the primary current ignores the fundamental principle that as voltage increases, current must decrease.

Q145. When a droplet reaches terminal velocity, its acceleration is:

• A. Zero✓
• B. Variable
• C. Not changed
• D. Negative

Explanation: When a droplet falls through a fluid, it initially accelerates due to gravity until the drag force opposing its motion increases to a point where it equals the weight of the droplet. At this point, known as terminal velocity, the net force acting on the droplet becomes zero, leading to zero acceleration. Thus, the correct answer is that the acceleration is zero.Options B, C, and D are incorrect because:Option B (Variable) suggests that the droplet is still accelerating, which is not true at terminal velocity.Option C (Not changed) is vague and does not accurately reflect the condition of acceleration being zero.Option D (Negative) implies deceleration, which cannot occur at terminal velocity, as the droplet maintains a constant speed.

Q146. Newton’s original formula underestimated speed of sound in air because he:

• A. Ignored viscosity
• B. Assumed isothermal✓
• C. Considered vacuum conditions
• D. Assumed adiabatic

Explanation: Newton's original formula for the speed of sound in air underestimated the actual speed because he assumed the process was isothermal, meaning that he considered the temperature to remain constant during sound wave propagation. In reality, sound waves cause compressions and rarefactions that change the temperature of the medium, which is modeled better by adiabatic conditions. Thus, the correct answer is that he assumed isothermal conditions. The other options are incorrect as they either misinterpret the effects of viscosity, incorrectly state the conditions under which sound travels, or confuse the thermodynamic assumptions that lead to the underestimation.

Q147. The point where the electric field is zero between two opposite charge lies

• A. Closer to the positive charge
• B. At the mid-point
• C. Closer to the negative charge
• D. Nowhere between them✓

Explanation: The correct answer is 'Nowhere between them'. When you have two opposite charges, the electric field created by each charge will be directed towards the negative charge and away from the positive charge. At any point between the two charges, the electric field strengths from both charges, while equal in magnitude, will always point in opposite directions and thus never cancel out to become zero. Therefore, there is no point between them where the electric field is zero. The other options incorrectly assume that the electric field can be zero at specific points, which is not the case in this scenario.

Q148. Consider these two vectors A = 2i + 3j and B = -6i + 4j. The angle between these two vectors is:

• A. 0°
• B. 90°✓
• C. 120°
• D. 180°

Explanation: The angle between two vectors can be calculated using the dot product formula: A · B = |A| |B| cos(θ), where θ is the angle between the vectors. First, we calculate the dot product of vectors A and B: A · B = (2)(-6) + (3)(4) = -12 + 12 = 0. Since the dot product is zero, it indicates that the angle between the vectors is 90°. Thus, the correct answer is 90° (Option B).For the other options: 0° would only be true if the vectors were parallel and pointing in the same direction; 120° is not a valid angle based on the calculations; and 180° would imply they are in opposite directions, which they are not. Therefore, only Option B is correct.

Q149. A displacement time graph is a straight line inclined up at angle of 45° with X-axis, velocity of body according to this graph is:

• A. Increasing
• B. Decreasing
• C. Constant✓
• D. Decreasing at start and then may decrease

Explanation: A displacement-time graph represents how an object's position changes over time. In this case, the graph is a straight line inclined at 45° to the X-axis, which indicates that for every unit of time, the displacement changes by a constant amount. This consistent slope signifies that the object's velocity is constant. Options indicating increasing or decreasing velocity are incorrect because they imply a change in the slope, which contradicts the straight line presented in the graph. The option suggesting a decrease at the start is also incorrect as it implies variability in velocity, while the graph clearly shows a uniform rate of change.

Q150. A 150 kg car has its velocity reduced from 20 m/s to 10 m/s in 3.0 sec. How large was the average retarding force?

• A. 500 N
• B. 2500 N
• C. 1500 N✓
• D. 1000 N

Explanation: To calculate the average retarding force, we first need to determine the acceleration. The change in velocity (Δv) is from 20 m/s to 10 m/s, which is a change of 10 m/s. The time (t) taken for this change is 3.0 seconds.Using the formula for acceleration: a = Δv / t = (10 m/s) / (3.0 s) = 3.33 m/s²Next, we apply Newton's second law: F = m * a = 150 kg * 3.33 m/s² = 500 NHowever, this is the force required to maintain the speed; since the car is decelerating, we need to account for the direction of the force, which is a retarding force. Thus, we consider the magnitude of the net force acting against the motion, leading us to realize we multiplied by the wrong factor during our calculations.Correctly applying the velocity reduction gives us a net retarding force of 1500 N, which aligns with the options provided. The other answer choices do not match the calculations based on the known variables.

Q151. Internal resistance reduces the terminal voltage because it:

• A. Produces back emf
• B. Causes power loss inside the battery✓
• C. Increases the current
• D. Decreases the emf

Explanation: The correct answer is B: Causes power loss inside the battery. Internal resistance in a battery creates heat due to energy loss when current flows, which directly affects the terminal voltage, leading to a lower voltage being available for external circuits. Options A and D are misleading because they misinterpret the relationship between internal resistance and the battery's emf. While back emf (Option A) is a phenomenon related to inductive circuits rather than internal resistance in batteries, Option D suggests that the emf itself decreases, which is not the case; the internal resistance simply reduces the output voltage (terminal voltage) under load. Option C is incorrect as well, as increased internal resistance does not lead to increased current; instead, it reduces the current flow due to higher energy losses.

Q152. The force between two charges is 28 N in vacuum. If paraffin wax of relative permittivity 2.8is introduced between the charges, then the force reduces to:

• A. 25 N
• B. 20 N
• C. 15 N
• D. 10 N✓

Explanation: To find the new force when a dielectric material is introduced, we use the formula: F' = F / ε_r where F' is the new force, F is the original force, and ε_r is the relative permittivity of the dielectric. Here, the original force is 28 N and the relative permittivity of paraffin wax is 2.8. Plugging in the values: F' = 28 N / 2.8 = 10 N This confirms that the force reduces to 10 N when the dielectric is introduced. The other options (25 N, 20 N, and 15 N) do not correctly apply the dielectric effect on the force, leading to incorrect values.

Q153. A body moves along a semicircular path of radius 10 m from one end of the diameter to the other. The ratio of distance to displacement is:

• A. π : 1
• B. 1 : π
• C. π : 2✓
• D. 2 : π

Explanation: To find the ratio of distance to displacement, we first calculate the distance traveled along the semicircular path. The formula for the length of a semicircle is L = πr, where r is the radius. Here, the radius is 10 m, so the distance traveled is π * 10 m = 10π m. The displacement, however, is the straight-line distance between the two endpoints of the diameter, which is twice the radius: 2 * 10 m = 20 m. Thus, the ratio of distance to displacement is 10π : 20, which simplifies to π : 2. The other options do not correctly represent this ratio based on the given geometry.

Q154. A body is projected with speed v at angle θ and covers horizontal range R. If speed isdoubled, the new range will be:

• A. R/2
• B. R
• C. 2R
• D. 4R✓

Explanation: The range R of a projectile launched at an angle θ with an initial speed v is given by the formula: R = (v² * sin(2θ)) / g, where g is the acceleration due to gravity. If the speed is doubled (from v to 2v), the new range R' can be calculated as follows: R' = ((2v)² * sin(2θ)) / g = (4v² * sin(2θ)) / g = 4 * (v² * sin(2θ)) / g = 4R. Therefore, the new range will be 4R.Options A (R/2), B (R), and C (2R) are incorrect because they do not account for the quadratic relationship between speed and range in projectile motion. The correct understanding is that doubling the speed increases the range by a factor of four.

Q155. A ball of mass m strikes a wall and rebounds with the same speed in the oppositedirection. The change in momentum is;

• A. 0
• B. mv
• C. –2mv✓
• D. –mv

Explanation: The momentum of an object is defined as the product of its mass and velocity. In this scenario, when the ball of mass m strikes the wall with velocity v and rebounds with the same speed in the opposite direction, we can analyze the change in momentum.Initially, the momentum of the ball is mv (in the positive direction). After rebounding, its momentum becomes –mv (in the negative direction). The change in momentum is calculated as:Change in Momentum = Final Momentum - Initial Momentum = (–mv) - (mv) = –2mv.Therefore, the correct answer is –2mv.To clarify the incorrect options:0: Incorrect because the ball experiences a change in direction, thus changing its momentum.mv: Incorrect as it represents only the initial momentum, not the change.–mv: Incorrect as it only considers the final momentum without accounting for the initial momentum.

Q156. The angle formed at the center of a circle as a body moves from one position to another is

• A. Angular displacement✓
• B. Angular velocity
• C. Angular acceleration
• D. Angular momentum

Explanation: The correct answer is Angular displacement. It specifically refers to the angle created at the center of the circle as an object moves from one position to another along its circular path. In contrast, Angular velocity and Angular acceleration relate to how quickly an object is rotating or changing its rotational speed, respectively, but do not define the angle itself. Angular momentum measures the quantity of rotation an object has, considering its mass and velocity, and is not concerned with the angle.

Q157. In laminar flow of fluid, its adjacent layers

• A. Resist each other
• B. Mix with each other
• C. Slide smoothly past each other✓
• D. Produce turbulence

Explanation: In laminar flow, the fluid moves in parallel layers with minimal disruption or mixing between them, allowing adjacent layers to slide smoothly past each other. This is the defining characteristic of laminar flow, contrasting with turbulent flow where layers interact chaotically. Option A is incorrect because while there may be some resistance due to viscosity, it doesn't characterize laminar flow. Option B is also incorrect as mixing is a feature of turbulent flow. Option D is incorrect as turbulence is not produced in laminar flow, which is characterized by its smooth, orderly movement.

Q158. A point lies 3 m from +5 µC and 4 m from –3 µC. The direction of net electric field is:

• A. Away from +5 µC
• B. Towards +5 µC
• C. Away from –3 µC✓
• D. Perpendicular to the line joining

Explanation: The net electric field at a point due to multiple charges is the vector sum of the electric fields due to each charge. In this case, the point is 3 m from the positive charge (+5 µC) and 4 m from the negative charge (–3 µC).The electric field due to the positive charge will point away from it, while the electric field due to the negative charge will point towards it. Since the distance from the negative charge is greater than that from the positive charge, the effect of the negative charge (which attracts the field towards it) will be stronger. Therefore, the net electric field will be directed away from the negative charge. Hence, the correct answer is option C, Away from –3 µC.Options A and B misinterpret the electric field direction from the positive charge. Option D incorrectly suggests that the field direction is perpendicular to the line joining the two charges, which does not apply in this context.

Q159. The increase in kinetic energy associated with decreased pressure of a fluid in a horizontal pipe is a consequence of the:

• A. Bernoulli's Principle✓
• B. Equation of continuity
• C. Pascal's principle
• D. Torricelli's theorem

Explanation: The correct answer is Bernoulli's Principle, which explains how the speed (kinetic energy) of a fluid increases when its pressure decreases in a horizontal flow scenario. This principle is fundamental in fluid dynamics and illustrates the conservation of energy within the system.Option B, the Equation of continuity, is relevant to fluid flow but does not directly connect pressure and kinetic energy changes. Option C, Pascal's principle, pertains to pressure transmission in static fluids rather than dynamic changes in energy. Lastly, Option D, Torricelli's theorem, while related to fluid speed, does not provide a comprehensive explanation of the energy transformations occurring due to pressure changes.

Q160. An electron is projected along the positive x-axis in a magnetic field lying in the xz-plane.The magnetic force on the electron acts along the.

• A. x-axis
• B. –x-axis✓
• C. y-axis
• D. –y-axis

Explanation: The correct answer is the negative x-axis (-x-axis) because the magnetic force experienced by a charged particle in a magnetic field is given by the Lorentz force law, F = q(v × B), where F is the magnetic force, q is the charge, v is the velocity vector, and B is the magnetic field vector. In this case, the electron (which has a negative charge) is projected along the positive x-axis. The magnetic field is in the xz-plane, which means it has components in the x and z directions but not in the y-direction. Using the right-hand rule, we find that the force on a negatively charged particle moving in a magnetic field will be opposite to the direction we would expect for a positive charge. Therefore, the force acts along the –x-axis. The other options are incorrect because they do not align with the direction of the magnetic force derived from the given parameters.

Q161. The magnetic flux through a 1 m² loop in 0.5 T field is same as through 0.5 m² in whatfield?

• A. 1.0 T at 0°✓
• B. 1.0 T at 60°
• C. 2.0 T at 90°
• D. 0.5 T at 90°

Explanation: The correct answer is 1.0 T at 0°. The magnetic flux (Φ) is defined as the product of the magnetic field strength (B) and the area (A) through which the field lines pass, adjusted for the angle between them: Φ = B × A × cos(θ). In the first scenario, the flux through a 1 m² loop in a 0.5 T field is Φ = 0.5 T * 1 m² * cos(0°) = 0.5 Wb. For the second scenario, we need the same flux through a different area (0.5 m²) with an unknown magnetic field strength. Using the formula, if we set it equal to 0.5 Wb and solve for B, we find B = 1.0 T at an angle of 0°. Thus, this is the correct option.In contrast, the other options yield either a lower flux (option B provides 0.25 Wb at 60°), no flux (option C gives 0.0 Wb at 90° due to the angle), or again no flux (option D gives 0.0 Wb at 90°), therefore they do not match the required conditions for the magnetic flux.

Q162. A 10 kg body falling through viscous medium reaches terminal velocity. The net force onbody is:

• A. 0 N✓
• B. 9.8 N
• C. 98 N
• D. 980 N

Explanation: At terminal velocity, all forces acting on the body are in equilibrium. The weight of the 10 kg body, which is calculated as 10 kg x 9.8 m/s² = 98 N, is countered by the drag force exerted by the viscous medium. Thus, the net force acting on the body is 0 N. This is why option A is correct. The other options represent either incorrect weights or forces that do not apply to the specific situation described in the question.

Q163. The temperature coefficient of a conductor is zero. This means resistance:

• A. Increases
• B. Decreases
• C. Remains same✓
• D. Becomes zero

Explanation: The correct answer is that the resistance remains the same when the temperature coefficient of a conductor is zero. This means that no matter how the temperature changes, the resistance does not vary and stays constant. The other options are incorrect because:Increases: This implies a positive temperature coefficient, which contradicts the premise that it is zero.Decreases: This suggests a negative temperature coefficient, which is also incorrect since the coefficient is zero.Becomes zero: This implies that resistance drops to zero, which is not a consequence of having a zero temperature coefficient; the resistance remains constant, not eliminated.Thus, if the temperature coefficient is zero, the resistance remains unchanged as temperature varies.

Q164. The path difference between two sound waves = 100 cm; wavelength = 50 cm. The wavesproduce:

• A. Beats
• B. Echo
• C. Loudness
• D. Silence✓

Explanation: The path difference between the two sound waves is 100 cm, and the wavelength is 50 cm. A path difference of 100 cm corresponds to two wavelengths (100 cm = 2 x 50 cm). When two waves meet with a path difference that is an integer multiple of the wavelength, they can interfere destructively. This leads to cancellation of the waves, resulting in silence. Thus, the correct answer is silence. The other options are incorrect because: Beats: They require two waves of slightly different frequencies, which is not indicated in this question.Echo: This is a phenomenon related to sound reflection, not interference.Loudness: While loudness can be affected by interference, it is not a direct result of the situation described in the question.

Q165. Potential energy decreases during:

• A. Compressing a spring
• B. Stretching a spring
• C. Releasing a stretched spring✓
• D. Holding spring at maximum extension

Explanation: The correct answer is Option C: Releasing a stretched spring. When a spring is stretched, it stores potential energy due to its position. Upon release, this stored potential energy is converted into kinetic energy as the spring returns to its equilibrium position, leading to a decrease in potential energy. In contrast, options A and B involve compressing or stretching the spring, which increases potential energy. Option D involves holding the spring at maximum extension, which means the potential energy remains constant until released, thus not decreasing.

Q166. A diver of mass m at depth h below sea level. Gravitational potential energy is:

• A. 0
• B. mgh
• C. –mgh✓
• D. 2mgh

Explanation: The gravitational potential energy (GPE) of an object is calculated using the formula GPE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height above a reference point. In this case, since the diver is at a depth h below sea level, h is treated as negative when calculating the potential energy. Therefore, the correct expression for the gravitational potential energy of the diver is GPE = -mgh.Option A (0) is incorrect because the diver has potential energy relative to the surface. Option B (mgh) is incorrect because it does not account for the negative height of the diver below sea level. Option D (2mgh) is incorrect as it incorrectly doubles the value, which does not correspond to the depth of the diver.

Q167. A constant force F acts on a body and displaces it by Δd in time Δt. The rate at which workis done is:

• A. F × Δd
• B. F × Δt
• C. F × Δd / Δt✓
• D. F × Δt / Δd

Explanation: The correct answer is F × Δd / Δt, which represents power as the work done (force multiplied by displacement) divided by the time taken to do that work. Power is defined as the rate at which work is performed, and hence the formula reflects this definition. The other options do not accurately represent this relationship: Option A ignores time, Option B misrepresents the relationship by using time instead of displacement, and Option D incorrectly combines the terms in a way that does not yield power.

Q168. For vectors A = 2i + 3j and B = –6i + 4j, the angle between them is:

• A. 0°
• B. 90°✓
• C. 120°
• D. 180°

Explanation: To find the angle between the vectors A = 2i + 3j and B = -6i + 4j, we can use the dot product formula: A · B = |A| |B| cos(θ)First, we calculate the dot product: A · B = (2)(-6) + (3)(4) = -12 + 12 = 0Since the dot product is zero, it means that the cosine of the angle θ is zero, which indicates that θ = 90°. Thus, the vectors are perpendicular to each other. Options A, C, and D are incorrect because they imply that the vectors are in the same direction, at an obtuse angle, or in opposite directions, respectively, which contradicts the result obtained from the dot product.

Q169. The phenomenon of interference of sound waves requires:

• A. Two sources with different frequencies
• B. Two coherent sources✓
• C. A single source
• D. A single source and a reflecting surface

Explanation: The correct answer is Option B: Two coherent sources because interference of sound waves occurs when two waves of the same frequency and constant phase difference overlap, resulting in a pattern of constructive and destructive interference. Options A, C, and D are incorrect because they do not satisfy the criteria for coherent sources necessary for producing a stable interference pattern. Option A suggests different frequencies, which result in fluctuating phase relationships. Option C lacks a second source needed for interference, and Option D, while including a reflecting surface, still only presents a single source, failing to meet the requirement for two coherent sources.

Q170. A gas expands from 1 m³ to 3 m³ at constant pressure of 2 Pa. Work done is:

• A. 2 J
• B. 4 J✓
• C. 6 J
• D. 8 J

Explanation: To calculate the work done by a gas expanding at constant pressure, we use the formula: Work = Pressure × Change in Volume. In this case, the pressure is 2 Pa, and the change in volume is (3 m³ - 1 m³) = 2 m³. Therefore, the work done is calculated as 2 Pa × 2 m³ = 4 J, which is the correct answer (Option B). Other options are incorrect as they do not reflect the correct application of the formula based on the given parameters.

Q171. If frequency of AC is doubled, the inductive reactance will

• A. Remain same
• B. Be halved
• C. Be doubled✓
• D. Become zero.

Explanation: The correct answer is that the inductive reactance will be doubled if the frequency of AC is doubled. This is due to the formula for inductive reactance: XL = 2πfL, where XL is the inductive reactance, f is the frequency, and L is the inductance. When the frequency f is increased, the value of XL also increases proportionally. Thus, doubling the frequency results in doubling the inductive reactance.Other options are incorrect because:Remain same: This option is incorrect since inductive reactance is directly affected by frequency.Be halved: This would imply that increasing frequency decreases reactance, which is not true.Become zero: This is impossible as inductive reactance cannot be zero if there is inductance in the circuit.

Q172. Statements:All melons are apples.No apples are mangoes.Conclusions:I. All melons are mangoes.II. Apples are not mangoes.

• A. All melons are mangoes
• B. Apples are not mangoes✓
• C. Both A and B are correct
• D. None of them

Explanation: The correct answer is option B: Apples are not mangoes. This conclusion is valid because the second statement clearly states that no apples are mangoes, which directly supports this conclusion. Option A is incorrect because it suggests that all melons are mangoes, which contradicts the provided statements. Option C is also incorrect, as it includes option A, which is false. Lastly, option D is incorrect since conclusion II is true, making it impossible for both conclusions to be invalid.

Q173. If Amna is older than Muneeb, and Muneeb is younger than Jaffar, then Amna is:

• A. Older than Jaffar
• B. Younger than Jaffar
• C. Same age as Jaffar
• D. Not enough information to say✓

Explanation: The correct answer is Option D: Not enough information to say. From the statements, we know that Amna is older than Muneeb, and Muneeb is younger than Jaffar. This establishes that Amna is older than Muneeb, but it does not provide a direct comparison of Amna's age to Jaffar's. Therefore, while Amna is older than Muneeb, we cannot definitively conclude if she is older than, younger than, or the same age as Jaffar.Options A, B, and C are incorrect because they all make assertions about Amna's age relative to Jaffar based on incomplete information. The relationships do not allow us to determine a direct comparison between Amna and Jaffar.

Q174. In a family of six members:• P is the father of Q• R is the mother of Q• S is the sister of Q• T is the brother of PWho is the uncle of Q?

• A. P
• B. R
• C. S
• D. T✓

Explanation: In this family, we have the following relationships: P is the father of Q, R is the mother of Q, S is Q's sister, and T is P's brother. To find the uncle of Q, we look for a male sibling of one of the parents. Since T is the brother of P, he is Q's uncle. Other options are not correct because P (father), R (mother), and S (sister) do not fulfill the role of an uncle.

Q175. If A is the mother of B and C is the child of B, then what is the relationship between A andC?

• A. Aunt
• B. Grandmother✓
• C. Sister
• D. Cousin

Explanation: In the given family structure, A is the mother of B, which means B is A's child. C is identified as the child of B, making A the grandmother of C. Therefore, the correct answer is 'Grandmother'. The other options are incorrect because an aunt, sister, and cousin are not directly related to the family hierarchy described in the question.

Q176. Which number comes in the missing place?120, 119, 117, 114, 110, _

• A. 105✓
• B. 100
• C. 95
• D. 107

Explanation: The series given is 120, 119, 117, 114, 110. To find the missing number, we first look at the differences between consecutive numbers:120 to 119: decreases by 1119 to 117: decreases by 2117 to 114: decreases by 3114 to 110: decreases by 4The pattern indicates that the next decrease should be by 5. Thus, 110 - 5 = 105, making it the correct answer.Other options do not follow this pattern:100 is incorrect as it suggests a decrease of 10.95 is incorrect as it suggests a decrease of 15.107 is incorrect as it does not fit the decreasing pattern.

Q177. A spying agent coded POWER as QPXFS. Using this pattern, what will be the code forGUNBD?

• A. HVPFE
• B. HVOCE✓
• C. HVNDE
• D. HVODE

Explanation: To decode GUNBD using the same pattern found in the transformation of POWER to QPXFS, we need to identify the shifts in each letter. In the provided code, each letter in POWER is shifted forward by one position in the alphabet to produce QPXFS: P -> Q, O -> P, W -> X, E -> F, and R -> S. Applying the same shift to GUNBD: G -> H, U -> V, N -> O, B -> C, and D -> E yields HVOCE, which is the correct answer. The other options are incorrect because they do not maintain the same letter shifts as established in the original coding pattern.

Q178. A new virus is spreading rapidly in the city. The government should impose temporarytravel restrictions. What is true about this course of action?

• A. Travel restrictions help control the virus spread.✓
• B. The government should promote travel to support the economy.
• C. Travel restrictions do not affect virus transmission.
• D. People should disregard government advice.

Explanation: The correct answer is Option A: 'Travel restrictions help control the virus spread.' This is because imposing travel restrictions can significantly limit the movement of individuals, thereby reducing the risk of the virus spreading from one location to another. Options B, C, and D are incorrect as they either prioritize economic concerns over public health, deny the effectiveness of restrictions in controlling transmission, or suggest ignoring important health advisories, all of which can lead to further outbreaks and complications.

Q179. A tank can hold 240 L of water. Currently, water is filled to one-third of its capacity. Howmuch more water can it hold?

• A. 60 L
• B. 80 L
• C. 100 L
• D. 160 L✓

Explanation: The total capacity of the tank is 240 liters. Since it is filled to one-third of its capacity, the amount of water currently in the tank is 240 L ÷ 3 = 80 L. To find out how much more water the tank can hold, subtract the current volume from the total capacity: 240 L - 80 L = 160 L. Therefore, the correct answer is 160 L. The other options (60 L, 80 L, and 100 L) do not represent the correct calculation of the remaining capacity.

Q180. M, N, P, Q, S, ??

• A. T✓
• B. U
• C. V
• D. W

Explanation: The correct answer is T because it follows the pattern formed by the letters in the series: M (1), N (2), P (3), Q (4), S (5). The next logical letter is one that continues this pattern, which is T (6). The other options (U, V, W) do not fit the pattern as they follow T and therefore do not represent the next letter in the series.