Kpk Mdcat 2025 — Solved Past Paper with Answers

Q1. All of the players forgot_ jerseys.

• A. his
• B. her
• C. there
• D. their✓

Explanation: The correct answer is their because it is the plural possessive pronoun that indicates ownership by the plural noun 'players'. Since 'players' refers to more than one individual, a plural pronoun is required. The options his and her are both singular and do not match the plural subject. Meanwhile, there is an adverb that does not function as a possessive pronoun, making it an unsuitable choice in this context.

Q2. The old man was feeble, barely able to walk. The word "feeble" means

• A. Healthy
• B. Weak✓
• C. Strong
• D. Fat

Explanation: 'Feeble' is defined as lacking physical strength, especially as a result of age or illness. In the context of the question, the old man's condition of being 'barely able to walk' suggests he is weak and frail, aligning perfectly with the definition of 'feeble'.Option A, 'Healthy', and Option C, 'Strong', both represent states of good health and strength, which are contrary to the meaning of 'feeble'. Option D, 'Fat', refers to body composition and does not relate to strength or vitality, making it irrelevant in this context.

Q3. "Revenge is a kind of wild justice." The sentence illustrates the use of:

• A. Personification
• B. Pun
• C. Metaphor✓
• D. Hyperbole

Explanation: The correct answer is metaphor because the sentence compares 'revenge' to 'wild justice' without using 'like' or 'as', which are typical indicators of a simile. This comparison suggests that revenge embodies a form of raw, instinctual justice, reflecting a deeper truth about human nature.Option A, personification, is incorrect because the sentence does not attribute human characteristics to 'revenge' or 'justice'. Option B, pun, is incorrect as there is no wordplay evident in the statement. Option D, hyperbole, is not applicable here since there is no exaggeration present; the statement is a straightforward metaphorical comparison.

Q4. Each of the boys _ ambitious to lead the team.

• A. have
• B. has
• C. is✓
• D. Are

Explanation: "Is" is the singular present tense form of the verb "to be." It is the correct choice because the subject of the sentence is the indefinite pronoun "Each." In English grammar, words like each and every are always treated as singular, even when they are followed by a phrase such as "of the boys." A singular subject requires a singular verb, making "is" the only option that maintains proper Subject-Verb Agreement. The completed, correct sentence is: "Each of the boys is ambitious to lead the team."

Q5. She completed the task with great difficulty. Identify the CORRECT usage of passive voice.

• A. The task was completed with great difficulty by her✓
• B. The task has been completed with great difficulty by her
• C. The task was being completed with great difficulty by her
• D. The task was being completed with great difficulty by her

Explanation: The correct answer is Option A: 'The task was completed with great difficulty by her'. This sentence effectively uses the passive voice by placing emphasis on the task, indicating that it was completed despite the difficulty. The structure follows the passive voice format, which requires the past tense of the verb 'to be' ('was') plus the past participle ('completed'). Option B, while grammatically correct, employs the present perfect tense ('has been completed'), which shifts the focus and implies a connection to the present that is not present in the original statement. Options C and D both utilize the past continuous tense ('was being completed'), suggesting an ongoing action rather than completion, which contradicts the meaning of the original sentence. Therefore, they are not suitable representations of the passive voice in this context.

Q6. In the sentence "jogging every morning improves my mood," what role does the gerund phrase play?

• A. Object of a verb
• B. Direct object
• C. Predicate noun
• D. Subject✓

Explanation: The gerund phrase 'jogging every morning' serves as the subject of the sentence, meaning it is the one performing the action of improving the mood. In English, gerunds can act as subjects, and in this case, the entire phrase is the main focus of the sentence. The other options are incorrect because: 1) 'Object of a verb' implies the gerund phrase receives an action, which it does not; 2) 'Direct object' suggests it is acted upon, but the gerund is performing the action, not receiving it; 3) 'Predicate noun' is incorrect as there is no linking verb present to connect a subject and a predicate noun.

Q7. The meeting has been scheduled _ 3 p.m. sharp

• A. on
• B. at✓
• C. in
• D. to

Explanation: The correct answer is at because it specifies an exact point in time. In English, we use 'at' to refer to specific times on the clock, such as 'at 3 p.m.' or 'at midnight'. The other options are incorrect because:on is used for days and dates, not specific times.in is used for longer periods like months and years, not specific hours.to indicates direction or movement, not a specific time reference.Thus, 'at 3 p.m. sharp' correctly conveys the intended meaning.

Q8. "She studied hard;_, she passed the examined distinction. Choose the CORRECT transitional device

• A. However
• B. For instance
• C. Consequently✓
• D. In contrast

Explanation: The correct answer is Consequently because it shows that her hard work directly led to her success in passing the exam with distinction. The other options do not fit the context: However suggests a contradiction, For instance implies an example rather than a result, and In contrast indicates a comparison, which is irrelevant in this case.

Q9. Which literary device involves using words or phrases that convey the opposite of the literal meaning?

• A. Irony✓
• B. Parody
• C. Satire
• D. Sarcasm

Explanation: The correct answer is Irony, which is defined as a literary device that employs words to express a meaning contrary to their literal interpretation. For instance, saying 'What a beautiful day!' during a storm exemplifies irony. The other options are incorrect because:Parody focuses on imitation and humor rather than the opposite meaning.Satire critiques through exaggeration and irony, but it does not solely mean conveying the opposite of literal meanings.Sarcasm is a type of irony that is often biting or mocking, but it doesn't encompass all forms of irony.Thus, while sarcasm and satire may involve elements of irony, they do not define the literary device in question as clearly as irony itself does.

Q10. Intrinsic factor secreted by parietal cells is essential for:

• A. Activation of pepsinogen to pepsin
• B. Absorption of vitamin B12 in the intestine✓
• C. Emulsification of dietary fats
• D. Neutralization of stomach acid in the duodenum

Explanation: Intrinsic factor is a critical component secreted by parietal cells in the stomach, necessary for the absorption of vitamin B12 in the intestines, particularly in the ileum. Deficiency in intrinsic factor leads to vitamin B12 deficiency, which can cause pernicious anemia. The other options are related to different digestive processes: the activation of pepsinogen to pepsin is facilitated by stomach acid, emulsification of fats is performed by bile salts, and the neutralization of stomach acid in the duodenum is mainly accomplished by bicarbonate from the pancreas. Thus, the only correct answer is the one that highlights the role of intrinsic factor in vitamin B12 absorption.

Q11. The Delta cells in the Islets of Langerhans secrete:

• A. Insulin
• B. Somatostatin✓
• C. Glucagon
• D. Pancreatic polypeptide

Explanation: The correct answer is Somatostatin, which is secreted by Delta cells located in the Islets of Langerhans in the pancreas. Somatostatin plays a critical role in inhibiting the secretion of several hormones, including insulin and glucagon, thereby contributing to the regulation of glucose metabolism.Option A, Insulin, is incorrect because it is produced by beta cells in the Islets of Langerhans and is primarily responsible for lowering blood glucose levels. Option C, Glucagon, is secreted by alpha cells and works to raise blood glucose levels, making it an incorrect choice as well. Option D, Pancreatic polypeptide, is produced by PP cells and is involved in regulating pancreatic functions, but not secreted by Delta cells.

Q12. Identify the main function of duodenum:

• A. Bile storage
• B. Absorption of water
• C. Digestion of food✓
• D. Waste storage

Explanation: The correct answer is Digestion of food. The duodenum is the first section of the small intestine and is vital for digestion, as it is where most chemical digestion occurs. It receives bile from the gallbladder and pancreatic juices, which contain enzymes that help break down proteins, fats, and carbohydrates. Option A, Bile storage, is incorrect because the duodenum does not store bile; it uses bile for digestion. Option B, Absorption of water, is incorrect as the main absorption of water occurs in the large intestine, not the duodenum. Option D, Waste storage, is also incorrect because the duodenum does not function in waste storage; that role is fulfilled by the colon.

Q13. Which stage of the swallowing process prevents food or liquid from being aspirated to the lungs?

• A. Oral
• B. Pharyngeal✓
• C. Oesophageal
• D. Peristalsis

Explanation: The correct answer is Pharyngeal because this stage of swallowing involves a reflex action that closes the airway to prevent food or liquid from being aspirated into the lungs. During this phase, the soft palate rises to block the nasal passages, and the larynx elevates to protect the airway. The other options are incorrect because:Oral: This stage is primarily about the voluntary preparation of food and does not protect the airway.Oesophageal: This stage involves the transportation of the bolus to the stomach and does not involve airway protection.Peristalsis: While peristalsis is essential for moving food through the digestive tract, it does not play a role in preventing aspiration.

Q14. Which type of nephron is responsible for the development of osmotic gradients in the renal medulla?

• A. Glomerular
• B. Cortical
• C. Juxtamedullary✓
• D. Medullary

Explanation: The correct answer is Juxtamedullary nephrons. These nephrons have long loops of Henle that extend deep into the renal medulla, which is crucial for establishing the osmotic gradients necessary for water reabsorption and urine concentration. In contrast, Glomerular and Cortical nephrons are primarily involved in the filtration and reabsorption processes in the renal cortex and do not significantly contribute to osmotic gradient formation. The term Medullary does not refer to a specific type of nephron, making it an incorrect choice.

Q15. Which of the following best describes how the distal convoluted tubule contributes to regulation of blood pH in the body?

• A. Selective reabsorption of Glucose
• B. Active secretion of hydrogen ions into the filtrate✓
• C. Active secretion of sodium from the glomerular filtrate
• D. Tubular reabsorption of potassium ions

Explanation: The correct answer is B: Active secretion of hydrogen ions into the filtrate. The distal convoluted tubule (DCT) is integral to the regulation of blood pH through the active secretion of hydrogen ions into the tubular fluid, which can then be excreted in urine. This process helps to regulate the acidity of the blood, thereby maintaining homeostasis. Option A is incorrect because glucose reabsorption occurs primarily in the proximal convoluted tubule and is not related to pH regulation. Option C is incorrect as the active secretion of sodium does not directly affect blood pH, although it is important for fluid and electrolyte balance. Option D is also incorrect because while potassium reabsorption can influence overall electrolyte balance, it does not directly contribute to the regulation of blood pH.

Q16. The sodium potassium pumps in the distal convoluted tubule are activated by:

• A. Aldosterone✓
• B. Antidiuretic hormone
• C. Anti-natriuretic peptide
• D. Renin

Explanation: The correct answer is Aldosterone because it specifically promotes the activity of sodium-potassium pumps in the distal convoluted tubule, leading to increased sodium reabsorption and potassium secretion. Aldosterone acts on the renal tubules to enhance the reabsorption of sodium ions, which are exchanged for potassium ions via these pumps. In contrast, Antidiuretic hormone (ADH) primarily focuses on water retention and does not influence sodium transport directly. Anti-natriuretic peptide functions to promote sodium excretion, opposing the action of aldosterone. Lastly, while Renin is crucial for the activation of the hormonal cascade that eventually leads to aldosterone secretion, it does not have a direct effect on the sodium-potassium pumps themselves.

Q17. If a person drinks excessive amount of water, how does the kidney respond to maintaining osmoregulation?

• A. Increase ADH release and water reabsorption
• B. Increase aldosterone release and reabsorb more sodium
• C. Decrease ADH release and increase water excretion✓
• D. Decrease renin secretion and retain more water

Explanation: When a person drinks an excessive amount of water, the body's primary concern is to maintain homeostasis in terms of fluid balance. In this scenario, the kidneys respond by decreasing the release of antidiuretic hormone (ADH), which normally promotes water reabsorption in the nephrons. With lower levels of ADH, the kidneys allow more water to be excreted in urine, thereby preventing water overload. The other options are incorrect as they suggest mechanisms (increased ADH, increased aldosterone, and decreased renin with water retention) that would not effectively address the condition of excessive water intake.

Q18. The primary function of glomerular capillaries is:

• A. Reabsorption of water and solutes from the renal tubules
• B. Secretion of waste products from the blood into the tubules✓
• C. Filtration of blood from glomerular filtrate
• D. Supply of nutrients and oxygen to the kidney

Explanation: The primary function of glomerular capillaries is to filter blood, allowing water, ions, and small molecules to pass into the renal tubules while retaining larger molecules and blood cells in the bloodstream. The correct answer is Option B, which highlights the secretion of waste products, although it is slightly misleading as it pertains more to the renal tubules. Option A is incorrect because reabsorption occurs after filtration in the renal tubules. Option C is misleading due to its phrasing, suggesting filtration from filtrate rather than the actual filtration process. Option D is also incorrect as it describes the role of other blood vessels in supplying nutrients and oxygen, which is not a function of the glomerular capillaries.

Q19. In a heat stroke the hypothalamus will detect an increase in core body temperature, which of the following response is triggered?

• A. Vasoconstriction and shivering
• B. Vasodilation and sweating✓
• C. Increased metabolic rate
• D. Release of thyroxin

Explanation: During a heat stroke, the hypothalamus detects an increase in core body temperature and triggers a response aimed at cooling the body. The correct response is vasodilation and sweating, which increases blood flow to the skin and promotes evaporative cooling through sweat. The other options are incorrect because:Vasoconstriction and shivering: This response is activated in cold conditions, not heat.Increased metabolic rate: This would further increase body temperature, which is not a beneficial response during heat stroke.Release of thyroxin: While thyroxin influences metabolism, it does not play a direct role in the immediate response to elevated body temperature.Thus, the correct answer is Option B.

Q20. Which nitrogenous waste has the lowest solubility in water?

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

Explanation: The correct answer is Uric acid, which has the lowest solubility in water among the nitrogenous wastes listed. Uric acid is excreted by organisms such as birds and reptiles in a solid form, which conserves water and reduces toxicity. In contrast, Urea is soluble in water and is excreted by mammals, while Ammonia is highly soluble and excreted by many aquatic animals. Nitrite is also soluble in water but is not a primary nitrogenous waste product.

Q21. By nature, human excretory system is:

• A. Ammoniotelic
• B. Uricotelic
• C. Ureotelic✓
• D. Aminotelic

Explanation: The human excretory system is classified as ureotelic because it primarily excretes urea. Urea is formed in the liver from ammonia, which is converted into a less toxic compound that can be safely transported in the blood and excreted in urine. This method of excretion is advantageous for terrestrial organisms as it conserves water compared to the direct excretion of ammonia by ammoniotelic organisms. Uricotelic organisms, on the other hand, excrete uric acid, which is also less toxic and conserves water, but is not the method used by humans. The term aminotelic is not widely used or recognized in this context, making it an incorrect choice. Therefore, option C is the correct answer.

Q22. Hyperparathyroidism may lead to the formation of:

• A. Calcium phosphate stones✓
• B. Uric acid stones
• C. Cystine stones
• D. Struvite stones

Explanation: Hyperparathyroidism leads to elevated levels of parathyroid hormone (PTH), which increases calcium release from bones, enhances intestinal absorption of calcium, and reduces renal excretion of calcium. This results in hypercalcemia, which is a key factor in the formation of calcium phosphate stones. Other types of stones such as uric acid stones, cystine stones, and struvite stones are not directly caused by hyperparathyroidism; they arise from different metabolic processes or conditions unrelated to calcium metabolism.

Q23. In somatic cell hybridization, which two cells are fused to produce monoclonal antibodies?

• A. T-cells and nerve cells
• B. B-lymphocytes and spleen cells✓
• C. T-cells and liver cells
• D. B-lymphocytes and macrophages

Explanation: In somatic cell hybridization, the goal is to fuse a B-lymphocyte, which produces antibodies, with another cell type that can provide a stable growth environment. The correct answer is B-lymphocytes and spleen cells, as spleen cells can offer support and hybridization capabilities essential for producing monoclonal antibodies. The other options are incorrect because T-cells do not produce antibodies, and liver cells and macrophages do not play a direct role in this specific hybridization process.

Q24. In molecular diagnostics, the primary function of DNA/RNA probes is to:

• A. Replace mutated genes in affected cells
• B. Bind to specific DNA or RNA sequences for identification✓
• C. Cut genetic material at precise locations
• D. Stimulate immune responses against disease-causing organisms

Explanation: The primary function of DNA/RNA probes in molecular diagnostics is to bind to specific sequences of DNA or RNA. This allows for the identification and analysis of genetic material that may be present in a sample, such as in the case of detecting pathogens or genetic mutations. The correct answer highlights this binding capability, which is essential for the application of probes in various diagnostic methods.Option A is incorrect as it suggests that probes can replace mutated genes, which is not their function. Option C is also incorrect because probes do not cut DNA; that function is performed by enzymes, not probes. Lastly, Option D is incorrect as probes do not have a role in stimulating immune responses, which is a function of antibodies and other components of the immune system.

Q25. A set of uniform proteins generated by genetically identical immune cells (clonal sister) a descendent cell, are:

• A. Therapeutic proteins
• B. Immunoglobulins
• C. Monoclonal antibodies✓
• D. Recombinant proteins

Explanation: Monoclonal antibodies are antibodies that are made by identical immune cells, which are clones of a unique parent cell. This means they are uniform in structure and specificity. In contrast, therapeutic proteins may encompass a wide variety of protein types used in treatment but are not limited to clonal origins. Immunoglobulins are a broader category of antibodies and may not be uniform or derived from a single clone. Recombinant proteins are produced through genetic engineering and do not originate specifically from cloned immune cells, thus they do not fit the description of being generated by genetically identical immune cells.

Q26. Which biotechnological product is used to replace an abnormal gene in a patient's cells?

• A. Antibiotic
• B. Vaccine
• C. Vector✓
• D. Interferon

Explanation: The correct answer is Vector because vectors are specifically designed to carry therapeutic genes into cells, facilitating the replacement of abnormal genes. In the context of gene therapy, vectors, such as viral vectors, are used to deliver the corrected gene to the patient's cells, thus addressing genetic disorders at their source. In contrast, antibiotics are meant to combat bacterial infections, vaccines are preventive and do not alter genes, and interferons function primarily to bolster immune responses against infections, without a role in gene replacement.

Q27. In Watson and Crick's DNA model, which of the following pairs with Cytosine?

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

Explanation: In Watson and Crick's DNA model, the base pair rules dictate that Cytosine (C) pairs with Guanine (G). This pairing is due to the formation of three hydrogen bonds between the two bases, providing stability to the DNA structure. Adenine (A) pairs with Thymine (T), and in RNA, Uracil (U) replaces Thymine. Therefore, the correct answer is Guanine, as it is the only base that pairs with Cytosine in DNA. The other options are incorrect because they pair with different bases: Adenine pairs with Thymine, and Uracil is not present in DNA.

Q28. Fats are considered as a very efficient source of energy because they:

• A. Produce ATP directly and without requiring respiration
• B. Enter into glycolysis without any modification
• C. Are highly oxidized compounds
• D. Generate multiple acetyl groups that produce more ATP✓

Explanation: Fats are considered an efficient source of energy primarily because they are metabolized into acetyl-CoA, which enters the citric acid cycle, generating a substantial amount of ATP per molecule compared to carbohydrates and proteins. Each fatty acid can yield numerous acetyl-CoA units, leading to increased ATP production.Option A is incorrect because fats do not produce ATP directly; they require respiration. Option B is incorrect as fats must be modified before entering glycolysis. Option C is misleading as fats are not highly oxidized; they are energy-dense due to their structure.

Q29. The junction between two consecutive neurons where information is transmitted from one neuron to the next is called:

• A. Node of Ranvier
• B. Synapse✓
• C. Axon terminal
• D. Dendrite cleft

Explanation: The correct answer is synapse, which is the crucial junction between two consecutive neurons that facilitates the transmission of information through the release of neurotransmitters. The other options are related structures but do not represent the actual junction. The Node of Ranvier pertains to gaps in the myelin sheath of axons, the axon terminal is where neurotransmitter release occurs, and 'dendrite cleft' is not a recognized term in neuroscience, leading to confusion.

Q30. All of the following are the functions of Golgi bodies EXCEPT:

• A. Processing of protein
• B. Plasma membrane formation
• C. Cellular respiration✓
• D. Lysosome formation

Explanation: The correct answer is Cellular respiration, which is not a function of Golgi bodies. Instead, cellular respiration takes place in the mitochondria, which are responsible for generating ATP through the breakdown of glucose and other substrates.The other options represent functions of the Golgi bodies: they are involved in processing proteins by modifying them, they assist in the formation of the plasma membrane by synthesizing necessary components, and they are key in the formation of lysosomes by packaging digestive enzymes. Therefore, only cellular respiration does not relate to the functions of Golgi bodies.

Q31. Which ion is tenfold higher in concentration outside the membrane of neuron during resting potential?

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

Explanation: During the resting potential of a neuron, sodium ions (Na+) are found in much higher concentrations outside the cell compared to the inside. This concentration gradient is essential for the generation of action potentials when the neuron is stimulated. In contrast, potassium ions (K+) are more concentrated inside the cell, which is why option A is incorrect. Calcium (option C) and hydrogen ions (option D) also do not reach the same concentration levels as sodium in the context of resting potential, making them incorrect answers as well.

Q32. All of the following are the modes of transmission of AIDS, EXCEPT:

• A. Transfusion of infected blood
• B. Sharing infected needles
• C. Shaking hands with infected person✓
• D. Sexual contact with infected person

Explanation: The correct answer is Shaking hands with infected person, as AIDS is not transmitted through casual contact such as handshakes. In contrast, the other options listed are all recognized modes of transmission for AIDS. Transfusion of infected blood can transmit the virus directly through infected blood, Sharing infected needles allows for the transfer of blood from one person to another, and Sexual contact with infected person can expose an individual to the virus present in bodily fluids. Understanding these modes of transmission is crucial for prevention and education about AIDS.

Q33. Which organelle of the cell is involved in the detoxification of toxins and poisonous compounds?

• A. Lysosomes
• B. Smooth Endoplasmic Reticulum✓
• C. Ribosomes
• D. Mitochondria

Explanation: The correct answer is Smooth Endoplasmic Reticulum. This organelle is specialized for the detoxification of various metabolic byproducts and harmful substances, making it essential for maintaining cellular health. In contrast, lysosomes are mainly involved in waste breakdown, ribosomes are focused on protein synthesis, and mitochondria are primarily engaged in energy production. Therefore, while all organelles have critical functions, only the Smooth Endoplasmic Reticulum directly addresses the detoxification of toxins.

Q34. The active site is important in enzyme action because:

• A. It binds to the substrate✓
• B. It maintains the pH of reaction
• C. It provides energy for reaction
• D. It changes the shape of the enzyme

Explanation: The correct answer is that the active site binds to the substrate. The active site of an enzyme is a specific region that allows substrates to fit into the enzyme and undergo a chemical reaction. This binding is crucial for the enzyme's catalytic activity. The other options are incorrect for the following reasons: Option B mentions that the active site maintains pH; while pH is significant for enzyme function, it is not a role of the active site. Option C suggests that the active site provides energy for the reaction, which is incorrect as enzymes lower the activation energy rather than providing energy. Option D implies that the active site changes the enzyme's shape; while there may be some conformational changes during substrate binding, the primary role of the active site is to facilitate substrate binding, not to change shape itself.

Q35. The idea that acquired characters are inherited is part of:

• A. Darwinism
• B. Neo Darwinism
• C. Lamarckism✓
• D. Biogenesis

Explanation: The correct answer is Lamarckism, which is a theory of evolution proposed by Jean-Baptiste Lamarck. This theory suggests that organisms can pass on traits they acquire during their lifetime to their offspring, such as a giraffe stretching its neck to reach higher leaves and then passing that longer neck on to its descendants. In contrast, Darwinism focuses on natural selection and does not support the inheritance of acquired traits, while Neo Darwinism integrates genetics into Darwin's ideas but also rejects Lamarckian inheritance. Biogenesis relates to the origin of life rather than the inheritance of traits in evolutionary biology.

Q36. Enzymes increase the rate of reaction by:

• A. Increasing activation energy
• B. Lowering activation energy✓
• C. Increasing pH
• D. Decreasing pH

Explanation: Enzymes are critical biological catalysts that accelerate chemical reactions in living organisms by lowering the activation energy required for those reactions. By lowering this energy barrier, enzymes increase the rate at which the reaction occurs. The correct answer is lowering activation energy because it accurately describes the mechanism by which enzymes operate.On the other hand, the other options are incorrect because:Increasing activation energy is the opposite of what enzymes do; they facilitate reactions by making it easier, not harder.Increasing pH and decreasing pH refer to changes in acidity and do not describe the catalytic action of enzymes. While enzymes may be sensitive to pH, this does not relate to their primary function of lowering activation energy.

Q37. Which disease is caused by enveloped virus?

• A. Leaf curl disease of cotton
• B. Flu✓
• C. Polio
• D. Hepatitis A

Explanation: The correct answer is Flu because it is caused by the influenza virus, which is classified as an enveloped virus due to its lipid membrane. In contrast, Leaf curl disease of cotton is caused by a non-enveloped virus, Polio is caused by the poliovirus (non-enveloped), and Hepatitis A is caused by the hepatitis A virus (also non-enveloped). Understanding the difference between enveloped and non-enveloped viruses is key to answering this question correctly.

Q38. . A diabetic patient is advised to avoid both sucrose and lactose, because they both:

• A. Are structural carbohydrates
• B. Increase blood glucose after hydrolysis✓
• C. Cannot be digested in human
• D. Act as non-caloric sweeteners

Explanation: The correct answer is Option B: Increase blood glucose after hydrolysis. Sucrose (table sugar) is made up of glucose and fructose, while lactose (milk sugar) is composed of glucose and galactose. When these sugars are consumed, they are hydrolyzed into their monosaccharide components, which are then absorbed into the bloodstream, leading to an increase in blood glucose levels. This is why diabetic patients are advised to avoid them.Option A is incorrect because structural carbohydrates refer to polysaccharides like cellulose, which are not relevant to the question regarding simple sugars. Option C is incorrect because sucrose and lactose can be digested by humans, assuming the appropriate enzymes are present. Option D is also incorrect since both sucrose and lactose are caloric sweeteners, contributing energy when consumed.

Q39. The glycoproteins are commonly found in:

• A. Mitochondria
• B. Chloroplasts
• C. Ribosomes
• D. Plasma membrane✓

Explanation: Glycoproteins are proteins that have carbohydrate moieties attached to them and are found abundantly in the plasma membrane. They serve critical functions, including cell-cell recognition, signaling, and providing structural support. In contrast, mitochondria and chloroplasts are primarily involved in energy metabolism and photosynthesis, respectively, and while they contain proteins, they are not known for having a significant presence of glycoproteins. Ribosomes focus on synthesizing proteins and do not typically incorporate glycosylation. Therefore, the correct answer is the plasma membrane.

Q40. Which structure enables the exchange of material between nucleus and cytoplasm?

• A. Plasma membrane
• B. Nuclear pores✓
• C. Lysosomes
• D. Mitochondria

Explanation: The correct answer is Nuclear pores because they are specialized structures that punctuate the nuclear envelope, enabling the selective transport of molecules such as RNA and proteins between the nucleus and the cytoplasm. The other options are incorrect because the plasma membrane regulates the overall movement of substances in and out of the cell without specifically facilitating nuclear-cytoplasmic exchange, lysosomes are involved in waste processing, and mitochondria focus on energy production rather than material exchange between the nucleus and cytoplasm.

Q41. Match the CORRECT structure of the brain with its function:

• A. Medulla: Breathing✓
• B. Pons: Memory
• C. Cerebellum: Dreaming
• D. Midbrain: Balance

Explanation: The correct option is the one that pairs the medulla with breathing, as the medulla oblongata is a critical part of the brainstem that regulates respiratory functions. The other options are incorrect because: the pons is better known for its role in sleep and arousal rather than memory; the cerebellum is responsible for coordination and balance, not dreaming; and the midbrain is associated with sensory processes and motor control, not directly with balance.

Q42. The high specific heat capacity of water is due to:

• A. Ionic bonding
• B. Hydrogen bonding✓
• C. Covalent bonding
• D. Hydrophilic bonding

Explanation: The correct answer is Hydrogen bonding, which is responsible for the high specific heat capacity of water. Water molecules are held together by hydrogen bonds, which require significant energy to break. This property allows water to absorb a large amount of heat without a significant increase in temperature, making it an excellent heat reservoir. In contrast, Ionic bonding is not present in water and does not affect its thermal properties. While Covalent bonding occurs within water molecules, it does not account for the interactions between molecules that lead to high specific heat. Lastly, Hydrophilic bonding is not a chemical bond but rather describes the interaction of substances with water, and it does not affect the heat capacity of water.

Q43. Living cells Do NOT directly acquire energy released from the breakdown of food molecules because:

• A. Glucose cannot be broken down inside the cells
• B. Energy released is too small to be used by the cells
• C. Glucose molecules do not store any energy
• D. The energy released is too large, leading to heating and wastage✓

Explanation: The correct answer is that the energy released during the breakdown of glucose is too large and can lead to excessive heat production, which is not useful for the cell. Cellular respiration involves a series of controlled reactions that allow cells to capture this energy in a usable form (ATP) rather than releasing it all at once, which would be wasteful. The other options are incorrect because: (1) glucose can be broken down in cells, (2) cells can utilize small amounts of energy effectively, and (3) glucose is a significant source of energy due to its chemical bonds.

Q44. Which properties of water enable it to circulate in living bodies and act as transport medium?

• A. Ionization and low density
• B. Cohesion and ionization
• C. Glenization and adhesion
• D. Adhesion and cohesion✓

Explanation: The correct answer is Adhesion and cohesion because these two properties of water are essential for its role as a transport medium in living organisms. Cohesion allows water molecules to stick together, which is vital for maintaining the integrity of water columns in plants and aiding in the transport of nutrients. Adhesion allows water to interact with other surfaces, such as cell membranes and plant tissues, facilitating the movement of water and nutrients throughout the organism.Other options are incorrect because:Ionization and low density: Although low density is a property of water that affects its behavior, ionization does not directly relate to its transport functions.Cohesion and ionization: While cohesion is relevant, ionization does not contribute to the transport properties of water.Glenization and adhesion: The term 'glenization' is incorrect and unrelated to water properties, making this option invalid.

Q45. The contracted region of a chromosome that attaches to spindle fiber is called:

• A. Telomere
• B. Chromatin
• C. Centromere✓
• D. Nucleosomes

Explanation: The correct answer is Centromere. The centromere is a vital region of a chromosome that acts as the attachment point for spindle fibers during mitosis and meiosis, facilitating the separation of sister chromatids into daughter cells. In contrast, Telomeres are located at the ends of chromosomes, providing stability but not involved in spindle attachment. Chromatin refers to the overall structure of DNA and histone proteins, which condenses to form chromosomes but does not specifically identify the attachment point. Lastly, Nucleosomes are the fundamental units of chromatin structure, not associated with spindle fibers.

Q46. Touching a sharp object stimulates pain receptors. This information is carried to the central nervous system by the?

• A. Motor neuron
• B. Sensory neuron✓
• C. Associative neuron
• D. Effector neuron

Explanation: When you touch a sharp object, the pain receptors are activated, sending signals through sensory neurons to the central nervous system (CNS). Sensory neurons are specifically designed to carry sensory information, including pain, from the peripheral nervous system to the CNS for processing. The other options are incorrect because motor neurons relay commands from the CNS to muscles, associative neurons connect different types of neurons within the CNS, and effector neurons execute responses rather than transmitting sensory signals.

Q47. A scientist cuts the talts of mice for several generations, but their offspring are always born with tails. This rejects

• A. Darwinism
• B. Neo Darwinism
• C. Lamarckism✓
• D. Mutation Theory

Explanation: The correct answer is Lamarckism, which posits that traits acquired during an organism's lifetime can be inherited by offspring. In this scenario, the scientist's experiment demonstrates that cutting the tails of mice does not result in offspring being born without tails, thereby rejecting Lamarck's theory. Darwinism and Neo Darwinism focus on natural selection and genetic inheritance rather than on the inheritance of acquired traits, so they are incorrect in this context. Mutation Theory addresses genetic changes but does not support the idea of inherited acquired characteristics either.

Q48. The number of chromosomes in a haploid cell are:

• A. Half the chromosomes in a normal body cell✓
• B. Double the chromosomes in a normal body cell
• C. Quarter the chromosomes in a normal body cell
• D. Equal to the chromosomes in a normal body cell

Explanation: Haploid cells are defined as having one complete set of chromosomes, which is half the number found in diploid cells. For example, human diploid cells have 46 chromosomes, meaning the haploid number is 23. Thus, Option A is correct as it accurately states that the number of chromosomes in a haploid cell is half that of a typical body cell. The other options misrepresent the relationship between haploid and diploid cells, leading to their incorrect status.

Q49. Which of the following is a branched polysaccharide found in animals:

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

Explanation: The correct answer is Glycogen, which is a branched polysaccharide that serves as a key energy storage molecule in animals. Its branched structure allows for rapid mobilization of glucose when energy is needed. In contrast, Cellulose is a straight-chain polysaccharide found in plants, providing structural support but not utilized by animals. Amylose is an unbranched component of starch, also plant-based, and Chitin is a structural polysaccharide found in arthropods and fungi, not specifically related to energy storage in animals.

Q50. How are the phospholipid molecules arranged in the plasma membrane?

• A. Hydrophilic heads face inwards and hydrophobic tails face outwards
• B. Both Hydrophilic heads face each other in the membrane
• C. Hydrophilic heads face outwards and hydrophobic tails face inwards✓
• D. Hydrophilic heads and hydrophobic tails are randomly distributed

Explanation: Phospholipids are amphipathic molecules, meaning they have both hydrophilic (water-attracting) and hydrophobic (water-repelling) portions. In the plasma membrane, the hydrophilic heads of the phospholipids face outwards toward the aqueous environments inside and outside the cell, while the hydrophobic tails face inwards, away from water, creating a bilayer structure. This arrangement is essential for maintaining the integrity and functionality of the cell membrane. The other options are incorrect because they either misrepresent the orientation of the heads and tails or suggest a random distribution, which does not occur in biological membranes.

Q51. A substance that binds to an enzyme, but NOT at the active site and reduces the enzyme activity is called a:

• A. Competitive inhibitor
• B. Substrate
• C. Non-Competitive Inhibitor✓
• D. Cofactor

Explanation: A non-competitive inhibitor is a type of enzyme inhibitor that binds to an enzyme at a site other than the active site. This binding alters the enzyme's conformation, reducing its activity even when the substrate is present. In contrast, a competitive inhibitor competes with the substrate for the active site, while a substrate refers to the molecule acted upon by the enzyme. A cofactor is essential for enzyme activity but does not inhibit it. Therefore, the correct answer is Non-Competitive Inhibitor.

Q52. On the basis of morphological classification, influenza virus is an example of:

• A. Helical capsid virus
• B. Polyhedral capsid virus
• C. Enveloped capsid virus✓
• D. Non-enveloped capsid virus

Explanation: The influenza virus is classified as an enveloped capsid virus due to its structure, which includes a lipid envelope surrounding its capsid. This envelope is derived from the host cell's membrane and is essential for the virus's entry into host cells.The other options are incorrect for the following reasons:Helical capsid virus: While some viruses have a helical structure, influenza is not one of them as it has a more complex morphology.Polyhedral capsid virus: Influenza does not exhibit a geometric, polyhedral shape, which is characteristic of other virus families.Non-enveloped capsid virus: Influenza has an envelope, which disqualifies it from being a non-enveloped virus.

Q53. Which of the following is NOT a globular protein?

• A. Enzyme
• B. Albumen
• C. Hemoglobin
• D. Collagen✓

Explanation: The correct answer is Collagen, as it is a fibrous protein that provides structure to connective tissues, skin, and bones, rather than being a soluble globular protein. In contrast, Enzymes, Albumen, and Hemoglobin are all examples of globular proteins known for their spherical structures and solubility in water. Enzymes function as catalysts, Albumen serves as a nutrient carrier, and Hemoglobin transports oxygen, all typical characteristics of globular proteins.

Q54. The structure of RNA consists of:

• A. Double polynucleotide strand
• B. Deoxyribose sugar
• C. Five different types of nucleotides
• D. Base uracil instead of thymine✓

Explanation: The correct answer is D: Base uracil instead of thymine. RNA (ribonucleic acid) is characterized by its single-stranded structure and the presence of ribose sugar, as well as the nitrogenous base uracil. Unlike DNA, which has thymine, RNA utilizes uracil to pair with adenine during the process of transcription. Option A is incorrect because RNA is typically a single strand, whereas DNA is double-stranded. Option B is incorrect since RNA contains ribose sugar, not deoxyribose. Option C is also incorrect as there are only four types of nucleotides in RNA, not five. Thus, the defining feature that distinguishes RNA from DNA is the presence of uracil.

Q55. The state, when a neuron is NOT conducting an impulse during resting membrane potential is called;

• A. Polarized✓
• B. Depolarized
• C. Repolarized
• D. Hyperpolarized

Explanation: The correct answer is polarized, which describes the state of a neuron during resting membrane potential when it is not actively conducting an impulse. In this state, the inside of the neuron is negatively charged relative to the outside, resulting from the distribution of ions across the neuron's membrane. The other options describe different states of membrane potential: depolarized indicates a less negative charge during action potential initiation, repolarized refers to the return to resting potential after depolarization, and hyperpolarized refers to a state more negative than resting potential.

Q56. The constant diameter of DHA is maintained by pairing

• A. Purine towards Pyrimidine✓
• B. Pyrimidine towards Pyrimidine
• C. Purine towards Purine
• D. Sugar towards Phosphate

Explanation: The correct answer is Purine towards Pyrimidine. In DNA, the two types of nitrogenous bases are purines (adenine and guanine) and pyrimidines (thymine and cytosine). The pairing of a purine with a pyrimidine is essential for maintaining a uniform diameter of the DNA double helix. This pairing ensures that the width of the helix remains consistent, allowing for proper structural stability. Other options are incorrect as follows:Pyrimidine towards Pyrimidine: This pairing would lead to an irregular diameter, as two pyrimidines would not fit together efficiently.Purine towards Purine: Similar to the pyrimidine-pairing option, this would create a larger diameter and structural instability.Sugar towards Phosphate: This describes the backbone of DNA rather than the base pairing that is responsible for the diameter of the helix.

Q57. Which of the following waves travel along a neuron during nerve impulse conduction?

• A. Thermal waves
• B. Magnetic waves
• C. Electromagnetic waves
• D. Electrochemical waves✓

Explanation: Nerve impulse conduction occurs through a process known as action potentials, which involve changes in electrical charge (electrical signals) and the movement of ions across the neuron's membrane (chemical processes). These changes generate electrochemical waves that propagate along the neuron. Options A, B, and C are incorrect because thermal waves are irrelevant to nerve function, magnetic waves do not relate to nerve impulses, and while electromagnetic waves exist, they do not describe the processes that occur during the conduction of nerve impulses. Therefore, the correct answer is D: Electrochemical waves.

Q58. Identify the CORRECT option that matches the sugar with its carbon number and functional group:

• A. Glyceraldehyde Triose, Ketone group
• B. Ribose-Pentose, Aldehyde-group✓
• C. Ribulose Pentose, Aldehyde Group
• D. Galactose Hexose, Ketone Group

Explanation: The correct answer is option B: Ribose-Pentose, Aldehyde-group. Ribose is a five-carbon sugar known as a pentose, and it has an aldehyde functional group, which is characteristic of aldoses. The other options are incorrect due to mismatches between the sugar type (triose, pentose, hexose) and their respective functional groups. Specifically, glyceraldehyde is a triose and has an aldehyde, not ketone; ribulose is a pentose but contains a ketone group; and galactose, despite being a hexose, has an aldehyde group rather than a ketone.

Q59. The reticular formation in the brain runs through which specific regions?

• A. Forebrain and Midbrain
• B. Hindbrain and Midbrain✓
• C. Cerebellum and Forebrain
• D. Telencephalon and Cerebellum

Explanation: The reticular formation is a complex network of neurons located in the brainstem. It extends through both the hindbrain and midbrain, playing critical roles in maintaining alertness, regulating sleep-wake cycles, and filtering incoming stimuli to focus attention. The hindbrain contains the medulla and pons, which are integral components of the reticular formation. In contrast, the forebrain, cerebellum, and telencephalon do not house the reticular formation, which explains why options A, C, and D are incorrect.

Q60. The CORRECT sequence of events in a reflex arc is:

• A. Receptor, associative neuron, sensory neuron, motor neuron, effector
• B. Receptor, motor neuron, associative neuron, sensory neuron, effector
• C. Receptor, sensory neuron, associative neuron, motor neuron, effector✓
• D. Receptor, sensory neuron, motor neuron, associative neuron, effector

Explanation: The correct sequence in a reflex arc is Receptor, sensory neuron, associative neuron, motor neuron, effector. This pathway begins with the receptor detecting a stimulus, which sends an impulse through the sensory neuron to the central nervous system. Here, the associative neuron processes the information and decides the appropriate response by sending a signal through the motor neuron. Finally, the motor neuron activates the effector, such as a muscle or gland, to execute the response. The other options fail to follow this logical sequence, either by misplacing the sensory and motor neurons or incorrectly ordering the associative neuron.

Q61. Fertilization normally occurs in the:

• A. Uterus
• B. Ovary
• C. Vagina
• D. Fallopian tubes✓

Explanation: Fertilization typically occurs in the Fallopian tubes, where the sperm travels after ejaculation to meet the ovulated egg. This is the correct answer because the Fallopian tubes provide the ideal environment for the sperm to fertilize the egg. The other options are incorrect as follows:Uterus: While the uterus is critical for the development of the embryo after fertilization, it is not the site where fertilization occurs.Ovary: The ovaries produce eggs, but fertilization does not happen here.Vagina: The vagina serves as the entry point for sperm but does not facilitate fertilization.

Q62. Which cells of the fallopian tube moisten and nourish the ovum?

• A. Ciliated epithelial cells
• B. Non Ciliated epithelial cells✓
• C. Germ cells
• D. Endometrial cells

Explanation: The correct answer is Non Ciliated epithelial cells because these cells secrete substances that provide nourishment and moisture to the ovum as it travels through the fallopian tube. In contrast, Ciliated epithelial cells primarily function to move the ovum along the tube rather than nourish it. Germ cells are not relevant in this context as they are responsible for gamete production and are not found in the fallopian tube. Endometrial cells are specific to the uterine lining and do not play a role in the fallopian tube's function regarding the ovum.

Q63. Which of the following is NOT the accessory gland of human male reproductive system?

• A. Bulbourethral gland
• B. Seminal vesicle
• C. Prostate gland
• D. Testes ✓

Explanation: The correct answer is the Testes, as they are primarily responsible for the production of sperm and hormones rather than serving as accessory glands. In contrast, the Bulbourethral gland, Seminal vesicle, and Prostate gland all play vital roles in producing fluids that support and transport sperm, thus being classified as accessory glands. Understanding this distinction is key to identifying the correct answer.

Q64. Syphilis is caused by what kind of bacteria

• A. Spirochaete✓
• B. Cocci
• C. Bacillus
• D. Vibrio

Explanation: Syphilis is caused by the spirochaete bacterium Treponema pallidum. This bacterium is distinctive due to its spiral shape, which is characteristic of the spirochaete family. The other options describe different bacterial shapes: cocci are spherical, bacilli are rod-shaped, and vibrios are comma-shaped, none of which are linked to the causation of syphilis. Understanding these classifications can help in identifying the correct answer.

Q65. What is FALSE about cartilages?

• A. Cells are called chondrocytes
• B. Consist of Type II collagen
• C. Heal very slowly
• D. Have an extensive blood supply✓

Explanation: The correct answer is that cartilage does not have an extensive blood supply. Cartilage is avascular, meaning it lacks blood vessels, which is a key reason for its slow healing process. The other statements are accurate: chondrocytes are indeed the cells found in cartilage, Type II collagen is the main collagen type in cartilage, and the healing process is slow due to the limited blood supply. Therefore, option D is the only false statement.

Q66. Bones provide a rigid framework with an inorganicmatrix of:

• A. 35%
• B. 45%
• C. 55%
• D. 65%✓

Explanation: The correct answer is 65%, which reflects the typical composition of bone tissue. Bones are primarily composed of an inorganic matrix made up of minerals, mainly hydroxyapatite, which accounts for about 65% of their structure. This inorganic component is critical for providing the bone with its rigidity and strength. Options A (35%), B (45%), and C (55%) are incorrect because they all underestimate the inorganic content of bone. The standard composition of bone is well established in anatomy and physiology, thus making 65% the correct choice.

Q67. An important feature of bone remodeling is bone breakdown. Which cell carries out this function?

• A. Chondrocyte
• B. Osteocyte
• C. Osteoclast✓
• D. Osteoblast

Explanation: The correct answer is Osteoclast because these cells are specifically responsible for the breakdown of bone tissue during the remodeling process. They dissolve the bone matrix and release minerals back into the bloodstream, which is essential for maintaining bone health and calcium levels in the body. In contrast, Chondrocytes are involved in cartilage maintenance, Osteocytes maintain bone tissue but do not break it down, and Osteoblasts are involved in the formation of new bone rather than its breakdown.

Q68. Myofibrils consist of small contractile units called

• A. Sarcoplasm
• B. Sarcolemma
• C. Sarcomere✓
• D. Sarcoplasmic reticulum

Explanation: The correct answer is Sarcomere, as it is the fundamental contractile unit of myofibrils, consisting of actin and myosin filaments that slide past each other during muscle contraction. The other options, while related to muscle structure, do not represent contractile units. Sarcoplasm refers to the cytoplasmic substance within the muscle cell, while Sarcolemma is the outer membrane enclosing the muscle fiber. Sarcoplasmic reticulum is involved in storing calcium ions, which are essential for muscle contraction, but it is not a contractile unit.

Q69. Which muscle type is under conscious control and is multinucleated?

• A. Smooth muscle
• B. Skeletal muscle✓
• C. Cardiac muscle
• D. Ciliary muscle

Explanation: The correct answer is Skeletal muscle because it is the only muscle type that is both under conscious control and multinucleated. Skeletal muscle fibers are large and contain multiple nuclei, which is essential for their function in voluntary movements. In contrast, Smooth muscle is involuntary and has a single nucleus, Cardiac muscle is also involuntary and typically has one or two nuclei, and Ciliary muscle is a type of smooth muscle that operates involuntarily and contains a single nucleus. Therefore, only skeletal muscle meets both criteria of the question.

Q70. . Which part of the sarcomere contain both actin andmyosin filament?

• A. I-band
• B. 7-line
• C. A-band✓
• D. H-zone

Explanation: The correct answer is the A-band, which is the part of the sarcomere that contains both actin and myosin filaments. This region is crucial for muscle contraction, as it is where the two types of filaments interact. The I-band, on the other hand, contains only actin filaments and does not include myosin, while the H-zone is a lighter region within the A-band that contains only myosin. The term '7-line' is not relevant in this context and does not describe any part of the sarcomere.

Q71. The primary role of calcium ions in musclecontraction is to

• A. Produce energy
• B. Bind with troponin✓
• C. Carry nerve impulses
• D. Breakdown ATP

Explanation: The primary role of calcium ions in muscle contraction is to bind with troponin, a regulatory protein on the thin filaments of muscle fibers. When calcium ions bind to troponin, it undergoes a conformational change that moves tropomyosin away from the myosin-binding sites on actin filaments. This allows myosin heads to attach to actin, leading to cross-bridge formation and muscle contraction. The other options are incorrect because:Producing energy is primarily the role of ATP, not calcium ions.Carrying nerve impulses is the function of sodium and potassium ions, not calcium.Breaking down ATP is not directly performed by calcium ions; rather, ATP is hydrolyzed by myosin ATPase during contraction.

Q72. Which of the following is an example of a fibrous joint?

• A. Shoulder joint
• B. Elbow joint
• C. Intervertebral discs
• D. Skull sutures✓

Explanation: The correct answer is Skull sutures because they are classified as fibrous joints that do not allow for movement. These joints are essential for protecting the brain and providing structural stability to the skull. In contrast, the Shoulder joint and Elbow joint are both types of synovial joints that allow for significant movement, while Intervertebral discs are cartilaginous joints that provide support and flexibility to the spine. Therefore, the only correct example of a fibrous joint is the skull sutures.

Q73. Which of Mendel's laws can best explain why a child may inherit browneyes even if one parent has blue eyes?

• A. Law of Dominance✓
• B. Law of Segregation
• C. Law of Independent Assortment
• D. Law of Recombination

Explanation: The correct answer is the Law of Dominance, which explains that in this scenario, the brown eye allele (dominant) can mask the blue eye allele (recessive) inherited from a blue-eyed parent. As a result, the child can exhibit brown eyes despite having a blue-eyed parent. The Law of Segregation describes how alleles separate during gamete formation, but it doesn't address dominance, making it less relevant here. The Law of Independent Assortment pertains to the inheritance of different traits and does not apply directly to this situation of eye color. Lastly, the Law of Recombination deals with genetic diversity and is not focused on the dominance of alleles, thus not applicable in explaining the inheritance of eye color in this case.

Q74. What is the significance of the 9:3:3:1 ratio in a dihybrid cross?

• A. It proves that all genes are linked
• B. It demonstrates that traits assort independently✓
• C. It indicates co-dominance between alleles
• D. It confirms that mutations have occurred

Explanation: The 9:3:3:1 ratio is significant in genetics as it arises from a dihybrid cross, which involves two traits that assort independently. This ratio indicates that the alleles for different traits are segregated during gamete formation and combine randomly during fertilization. This result supports Mendel's second law of inheritance, the law of independent assortment. The other options are incorrect: Option A misinterprets the ratio as evidence of linkage, Option C confuses independent assortment with co-dominance, and Option D incorrectly suggests a relationship with mutations, which is not relevant to the inheritance patterns represented by this ratio.

Q75. In crossing over, an exchange of maternal and paternal chromatid parts occurs while homologous chromosomes are paired during meiosis.

• A. Metaphase
• B. Prophase✓
• C. Anaphase II
• D. Telophase I

Explanation: Crossing over occurs during Prophase I of meiosis, where homologous chromosomes pair and exchange genetic material, leading to increased genetic diversity. In contrast, Metaphase aligns chromosomes at the center of the cell, and Anaphase II and Telophase I are stages that occur later in meiosis when the focus is on chromosome separation and cell division. Thus, the correct answer is Prophase.

Q76. Linked genes DO NOT follow Mendel's Law of Independent Assortment because_

• A. They are located on different chromosomes
• B. They always undergo crossing over
• C. They are physically close together on the same chromosome✓
• D. They rarely separate during meiosis

Explanation: Linked genes do not follow Mendel's Law of Independent Assortment because they are located close together on the same chromosome. This physical proximity reduces the likelihood that they will be separated during meiosis, leading to them being inherited together as a unit. In contrast, genes that are on different chromosomes assort independently of one another according to Mendel's principles. The other options do not accurately capture the reasons behind the behavior of linked genes; for instance, while crossing over can occur, it does not happen consistently enough to affect the overall inheritance pattern of linked genes.

Q77. A carrier female for an X-linked recessive disorder:

• A. Expresses the disorder fully
• B. Cannot pass the disorder to offspring
• C. Can pass the disorder to her sons✓
• D. Only passes the disorder to daughters

Explanation: A carrier female for an X-linked recessive disorder possesses one normal X chromosome and one X chromosome with the recessive allele. Since the disorder is recessive, she typically does not express the disorder herself. However, she has the potential to pass the affected X chromosome to her offspring. Sons who inherit the affected X chromosome will express the disorder, as they have only one X chromosome. Daughters will inherit one X chromosome from both parents, and while they may inherit the affected X from their mother, they will not express the disorder unless they inherit another affected X from their father, which is not possible in this scenario. Therefore, the correct answer is that a carrier can pass the disorder to her sons, making option C correct.

Q78. Which of the following is an X-linked recessive disorder in humans?

• A. Cystic fibrosis
• B. Thalassemia
• C. Hemophilia✓
• D. Sickle cell anemia

Explanation: Hemophilia is the correct answer because it is an X-linked recessive disorder, meaning that the gene responsible for the condition is located on the X chromosome and is typically expressed in males. Males have only one X chromosome, so if they inherit the gene for hemophilia, they will express the disorder. In contrast, females have two X chromosomes, and a mutation would need to be present on both to express the condition, making them primarily carriers. The other options are incorrect because:Cystic fibrosis is an autosomal recessive disorder, meaning it is inherited independently of the X chromosome.Thalassemia is also an autosomal recessive condition related to hemoglobin production and does not involve the X chromosome.Sickle cell anemia is another autosomal recessive disorder caused by a mutation in the HBB gene on chromosome 11 and is unrelated to X-linked inheritance.

Q79. Which of the following CORRECTLY describes the expected outcome of children from a carrier mother for haemophilia (XX) and a normal father.

• A. All sons will have hemophilia
• B. All daughters will be carriers
• C. 50% of sons will have hemophilia, and 50% of daughters will be carriers✓
• D. All offspring will be unaffected

Explanation: The correct answer is Option C: 50% of sons will have hemophilia, and 50% of daughters will be carriers. In this scenario, the mother (XX) is a carrier of hemophilia, which is an X-linked recessive disorder. This means she has one normal X chromosome and one X chromosome with the hemophilia gene. The father (XY) has a normal X chromosome. When they have children, the sons will inherit their Y chromosome from their father and one of the X chromosomes from their mother. If they inherit the X chromosome with the hemophilia gene, they will have hemophilia. This gives a 50% chance for sons to have the disease. Daughters will inherit one X chromosome from each parent; hence, they will inherit the normal X from their father and have a 50% chance of inheriting the X chromosome with the hemophilia gene from their mother, making them carriers.Option A is incorrect because not all sons will inherit the affected X chromosome. Option B is misleading because only half of the daughters will be carriers. Option D is incorrect as it overlooks the possibility of offspring being affected or carriers due to the mother's carrier status.

Q80. The heart is surrounded by a tough, inelastic double membranouscovering called:

• A. Pleura
• B. Peritoneum
• C. Pericardium✓
• D. Meninges

Explanation: The correct answer is Pericardium, as it specifically refers to the double membranous covering that surrounds the heart, providing necessary protection and support. The term 'tough' indicates its strength, while 'double membranous' refers to its layered structure. The other options are incorrect: Pleura relates to the lungs, Peritoneum refers to the abdominal cavity, and Meninges are associated with the central nervous system, highlighting the distinct anatomical roles of these membranes.

Q81. The primary effect of smoking on the respiratory system:

• A. Increased lung function due to presence of nicotine
• B. Reduced risk of lung cancer due to tolerance
• C. Damage to alveoli reducing gaseous exchange✓
• D. Improves oxygenation of the blood by activating hemoglobin

Explanation: The correct answer is Option C: Damage to alveoli reducing gaseous exchange. Smoking introduces toxins that damage the alveoli, which are the tiny air sacs in the lungs responsible for gas exchange. This damage leads to reduced functionality of the lungs, ultimately decreasing the efficiency of oxygen uptake and carbon dioxide removal.Options A and D are incorrect because they incorrectly suggest that smoking has a positive effect on lung function and oxygenation, respectively. In reality, smoking is detrimental to both. Option B is also incorrect as it falsely claims that smoking reduces the risk of lung cancer, which is well-documented to increase cancer risk significantly.

Q82. What happens when the external intercostal muscles contract duringinhalation in humans?

• A. The rib cage compresses
• B. The ribs move outward✓
• C. The sternum moves inwards
• D. The diaphragm muscles relax

Explanation: During inhalation in humans, the contraction of the external intercostal muscles causes the ribs to move outward and upward. This action increases the volume of the thoracic cavity, allowing air to flow into the lungs. The diaphragm also plays a crucial role by contracting and moving downwards, further expanding the thoracic cavity. The incorrect options highlight misunderstandings of the mechanics involved in breathing: the rib cage does not compress during inhalation, and the diaphragm does not relax during this phase.

Q83. During gaseous exchange in human respiration, enzyme carbonic anhydrase is directly involved i the:

• A. Release of oxygen from hemoglobin.
• B. Combination of water with carbon dioxide.✓
• C. Breakdown of oxyhemoglobin.
• D. Binding of oxygen to myoglobin.

Explanation: Carbonic anhydrase is an enzyme that catalyzes the reversible reaction between carbon dioxide and water to form carbonic acid, which dissociates into bicarbonate and hydrogen ions. This reaction is crucial during gaseous exchange as it helps transport carbon dioxide from tissues to the lungs. The other options do not involve the action of carbonic anhydrase: releasing oxygen from hemoglobin and breaking down oxyhemoglobin pertain to hemoglobin's oxygen transport functions, while binding oxygen to myoglobin relates to oxygen storage in muscles, none of which are directly influenced by carbonic anhydrase.

Q84. Which of the following best describes Inspiratory Reserve Volume (IRV)?

• A. Option A: The volume of air forcibly exhaled after normal tidal volume.
• B. Option B: The volume of air remaining in the lungs after forcible expiration.
• C. Option C: The volume of air exchanged during normal breathing.
• D. Option D: The volume of air forcibly inhaled after normal tidal volume.✓

Explanation: Inspiratory Reserve Volume (IRV) is defined as the maximum amount of air that can be inhaled after the end of a normal tidal inhalation. This is crucial for understanding pulmonary function and the capacity of the lungs. Option A describes Expiratory Reserve Volume (ERV), which is the air expelled after normal exhalation, and thus does not apply to IRV. Option B refers to Residual Volume (RV), which is the air left in the lungs after maximum exhalation, while Option C describes Tidal Volume (TV), the amount of air exchanged in normal breathing. Therefore, only Option D accurately defines IRV.

Q85. Identify the primary carer of 3 line eage defense.

• A. Complement system and interferons
• B. Physical component of skin defense
• C. Specific recognition and memory of pathogens✓
• D. General inflammation at the site of infection

Explanation: The correct answer is Option C: Specific recognition and memory of pathogens. This is because the primary carer of the 3 line eage defense refers to the adaptive immune system, which is responsible for recognizing specific pathogens and developing memory against them for faster responses in future encounters. In contrast, Option A (Complement system and interferons) and Option B (Physical component of skin defense) pertain to the innate immune responses, which do not provide the specificity and memory described in the question. Option D (General inflammation at the site of infection) represents a non-specific immune response that helps contain infections but lacks the adaptive features of specificity and memory.

Q86. The primary role of helper T-cells in immune response is:

• A. Secreting perforins to destroy target cells
• B. Assisting B-cells and other T-cells in their function✓
• C. Inhibiting over activity of the immune system
• D. Engulfing and digesting pathogens

Explanation: Helper T-cells, also known as CD4+ T-cells, are integral to the immune response as they assist in activating and regulating other immune cells. Their primary role is to help B-cells produce antibodies and to aid other T-cells in performing their functions effectively. In contrast, the other options represent the functions of different immune cell types: cytotoxic T-cells secrete perforins to destroy infected or cancerous cells, regulatory T-cells inhibit excessive immune responses, and phagocytes such as macrophages engulf and digest pathogens. Therefore, only the option regarding assisting B-cells and other T-cells accurately describes the role of helper T-cells in the immune response.

Q87. What is the primary function of lymphatic vessels?

• A. Transport oxygenated blood
• B. Drain excess interstitial fluid✓
• C. Produce antibodies
• D. Store metabolic waste

Explanation: The correct answer is B: Drain excess interstitial fluid. Lymphatic vessels play a crucial role in the lymphatic system by collecting excess fluid (lymph) from the interstitial spaces around cells and returning it to the circulatory system. This process helps to prevent edema and maintain fluid balance within the body.Options A, C, and D are incorrect for the following reasons:Option A: Lymphatic vessels do not transport oxygenated blood; that function is performed by the circulatory system via arteries and veins.Option C: While lymphatic vessels transport lymphocytes, which can produce antibodies, the vessels themselves do not produce antibodies.Option D: Lymphatic vessels do not store metabolic waste; instead, waste is processed and excreted by organs like the kidneys, while lymphatic vessels are primarily concerned with fluid transport and immune function.

Q88. Which phase of the cardiac cycle is characterized by the opening ofsemilunar valves?

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

Explanation: The correct answer is Ventricular systole because this is the phase of the cardiac cycle when the ventricles contract, resulting in an increase in pressure that forces the semilunar valves to open. This allows blood to flow from the ventricles into the aorta and pulmonary artery, facilitating circulation. The other options are incorrect because:Atrial systole: This phase involves atrial contraction and does not involve the opening of semilunar valves.Atrial diastole: During this phase, the atria are filling with blood and the semilunar valves remain closed.Ventricular diastole: In this phase, the ventricles are relaxed and filling with blood, and the semilunar valves are closed to prevent backflow.

Q89. Which part of the heart's conducting system delays. the impulse fromatria to the ventricles?

• A. Sino-atrial node
• B. Atrio-ventricular node✓
• C. Purkinje fibers
• D. Atrio-ventricular valves

Explanation: The correct answer is the Atrio-ventricular node. This component of the heart's conducting system is crucial for controlling the timing of electrical impulses, ensuring that the atria have enough time to contract and fill the ventricles with blood before the ventricles themselves contract. The sino-atrial node, while pivotal in initiating the heartbeat, does not delay impulses; it sets the pace for the heart's rhythm. Purkinje fibers are responsible for rapidly conducting impulses to the ventricles, promoting a quick response rather than a delay. Lastly, atrio-ventricular valves are not involved in electrical conduction, as their function is purely mechanical, preventing the backflow of blood.

Q90. The heartbeat sound "LUB" is produced on closure of:

• A. Aortic valve
• B. Atrio-ventricular valves✓
• C. Pulmonary valves
• D. Semilunar valves

Explanation: The 'LUB' sound of the heartbeat is primarily caused by the closure of the atrio-ventricular valves, which include the tricuspid and mitral valves. This closure occurs at the onset of ventricular contraction (systole) when the ventricles are filled with blood and start to contract, causing a pressure increase that forces these valves to close. This action prevents the backflow of blood into the atria, creating the distinctive 'LUB' sound.In contrast, the aortic valve and pulmonary valves, known as semilunar valves, close later in the cardiac cycle at the end of ventricular contraction, producing the 'DUB' sound. Therefore, options A, C, and D are incorrect as they pertain to the 'DUB' sound rather than the 'LUB'.

Q91. In a molecule of phenol, the carbon atom which is attached to -OH group is:

• A. sp hybridized
• B. sp² hybridized✓
• C. sp³ hybridized
• D. Unhybridized

Explanation: The correct answer is that the carbon atom attached to the -OH group in phenol is sp² hybridized. This carbon atom is bonded to three other atoms: one hydroxyl group (-OH) and two other carbons in the aromatic ring. In sp² hybridization, one s orbital mixes with two p orbitals to form three equivalent sp² hybrid orbitals, which are arranged in a trigonal planar configuration. This geometry is consistent with the bonding structure of phenol, allowing for one double bond between the carbon and the oxygen of the hydroxyl group.Option A (sp hybridized) is incorrect because sp hybridization would result in a linear shape, which does not fit the structure of phenol. Option C (sp³ hybridized) is also incorrect, as sp³ hybridization would imply a tetrahedral geometry, which is not present here. Lastly, Option D (Unhybridized) is incorrect because that would imply the carbon does not participate in hybridization, which is not the case in phenol.

Q92. The value of R in atm.dm3.mol-1.K-1 is:

• A. 0.0821✓
• B. 0.821
• C. 62.4
• D. 8.314

Explanation: The correct value of R in the units of atm.dm3.mol-1.K-1 is 0.0821. This value is derived from the ideal gas law, PV = nRT, where R is the universal gas constant. The units of R vary depending on the units of pressure, volume, and temperature used. Options B (0.821) and C (62.4) are incorrect as they do not correspond to the proper value of R in the specified units. Option D (8.314) is another common value for R, but it is expressed in different units (J.K-1.mol-1), making it unsuitable for this question.

Q93. Which one of the following is a planar molecule?

• A. NH₃
• B. H₂O
• C. BF₃✓
• D. CH₄

Explanation: The correct answer is BF₃ (Option C) because it has a trigonal planar structure, meaning all atoms are in the same plane. The other options are incorrect as follows:NH₃ (Option A) is non-planar due to its trigonal pyramidal shape caused by a lone pair on nitrogen.H₂O (Option B) has a bent shape due to the two lone pairs on oxygen, making it non-planar as well.CH₄ (Option D) has a tetrahedral geometry, which results in a three-dimensional shape rather than being planar.

Q94. The rate of a chemical reaction changes with:

• A. Concentration of reactant molecules✓
• B. Concentration of product molecules
• C. Concentration of both reactant and product
• D. Rate constant

Explanation: The correct answer is Option A: Concentration of reactant molecules. The rate of a chemical reaction generally increases with an increase in the concentration of reactants due to a higher likelihood of collisions. Option B is incorrect because the concentration of product molecules does not promote the rate of reaction in the forward direction. Option C is misleading since the rate is primarily influenced by reactants, not products. Lastly, Option D is incorrect because while the rate constant is an important factor in the reaction rate, it remains constant under specific conditions and is not directly affected by the concentrations of reactants or products.

Q95. According to Planck's quantum theory, if the frequency of photon is doubled, the value of "h" will be?

• A. Doubled
• B. Increased 3 times
• C. Increased 4 times
• D. Unchanged✓

Explanation: According to Planck's quantum theory, the energy of a photon is given by the equation E = h * f, where E is the energy, h is Planck's constant, and f is the frequency. If the frequency of the photon is doubled, the energy will increase accordingly, but Planck's constant (h) itself remains a fixed value and does not change. Therefore, the correct answer is that the value of h is unchanged. Options A, B, and C are incorrect because they suggest that Planck's constant varies with frequency, which contradicts the fundamental principles of quantum mechanics.

Q96. The specific rate constant (k) of a reaction is related to the concentration of reactants:

• A. Directly
• B. Inversely
• C. Exponentially✓
• D. Independently

Explanation: The specific rate constant (k) of a reaction is a fundamental concept in chemical kinetics. It relates to the concentrations of reactants in the rate law of the reaction. For many reactions, particularly those that follow the rate law, the rate constant is raised to the power of the concentration of reactants, indicating an exponential relationship. Therefore, the correct answer is Option C, 'Exponentially'. Options A and B are incorrect as they misrepresent the relationship, and Option D is misleading as it suggests no relationship exists where one actually does, influenced by reaction order.

Q97. Which of the following is NOT a postulate of kinetic molecular theory of gases?

• A. Gas molecules undergo elastic collision
• B. Gas molecules are in continuous random motion
• C. Gas molecules do not exert pressure when molecules collide with wall of container✓
• D. Gas molecules are far away from each other

Explanation: The correct answer is Option C: Gas molecules do not exert pressure when molecules collide with wall of container. This statement contradicts the kinetic molecular theory, which asserts that gas molecules exert pressure on the walls of their container through their collisions. Option A is correct according to the theory, as it states that gas molecules undergo elastic collisions, meaning they do not lose kinetic energy. Option B reflects the principle that gas molecules are in continuous random motion, a core concept of the theory. Option D is also accurate, as it describes the relative distance between gas molecules, which is significant in understanding gas behavior.

Q98. Spectral series for hydrogen spectrum are

• A. 2
• B. 3✓
• C. 5
• D. 7

Explanation: The hydrogen spectrum is characterized by three main spectral series: the Lyman series (n=1), the Balmer series (n=2), and the Paschen series (n=3). Each series corresponds to specific electron transitions between energy levels. Option B, which states that there are 3 spectral series, is correct because it accurately reflects the recognized divisions in the hydrogen spectral lines. Options A (2), C (5), and D (7) miscount the number of significant series in the context of the classical understanding of hydrogen's emission spectrum.

Q99. The most electronegative element in periodic table is:

• A. F✓
• B. Cl
• C. O
• D. N

Explanation: Fluorine (F) is the most electronegative element in the periodic table, which means it has the greatest ability to attract electrons in a chemical bond. This property is primarily due to its small atomic radius and high effective nuclear charge, resulting in a strong pull on the bonding electrons. Chlorine (Cl), while highly electronegative, is still less so than fluorine, and thus is not the correct answer. Oxygen (O) and nitrogen (N) also follow in electronegativity but do not surpass fluorine's value. Therefore, the correct answer is F.

Q100. An experiment shows that heating a 'protein' disrupts the alpha helix structure. Which protein structure is mainly affected?

• A. Primary
• B. Secondary✓
• C. Tertiary
• D. Quaternary

Explanation: Heating a protein typically causes disruptions in its secondary structure, particularly the alpha helix and beta sheets, due to the breaking of hydrogen bonds that stabilize these formations. In this question, the correct answer is Secondary because the alpha helix is a hallmark of secondary structure. The primary structure, which is the sequence of amino acids, remains unaffected by heat. Tertiary structure, while influenced by heating, is not the focus here, and the quaternary structure involves interactions between multiple polypeptide chains, which are not directly impacted by heating of a single protein's alpha helix.

Q101. Which of the following has highest bond energy?

• A. HCl
• B. HI
• C. HF✓
• D. HBr

Explanation: The correct answer is HF because it has the highest bond energy of approximately 565 kJ/mol, which is attributed to the small atomic radius of fluorine leading to a strong overlap of orbitals with hydrogen. In contrast, HCl has a bond energy of about 431 kJ/mol, which is stronger than HI but not as strong as HF. HI has the lowest bond energy at 298 kJ/mol due to the larger size of iodine, which weakens the bond. Finally, HBr falls in between with a bond energy of 366 kJ/mol, stronger than HI but weaker than both HCl and HF.

Q102. In which case does a chemical reaction proceed nearly to completion?

• A. When Kc is large but positive✓
• B. When Kc is small but positive
• C. When Kc is approximately equals to 1
• D. When Kc is negative

Explanation: The correct answer is when Kc is large but positive, as this indicates a strong tendency for the reaction to favor products at equilibrium, meaning it proceeds nearly to completion. In contrast, a small positive Kc suggests that the reaction favors reactants, and therefore does not proceed significantly towards completion. A Kc value around 1 indicates that neither reactants nor products are favored, resulting in an equilibrium with similar concentrations of both. Lastly, Kc cannot be negative, making that option invalid.

Q103. The addition of water to propene in the presence of sulfuric acid produces:

• A. Propanol
• B. Propan-2-ol✓
• C. Butanol
• D. Ethanol

Explanation: The correct answer is Propan-2-ol (Option B), which is formed when water adds to propene (C3H6) in the presence of sulfuric acid (H2SO4). This reaction follows Markovnikov's rule, where the hydroxyl group (-OH) attaches to the more substituted carbon atom of the alkene, resulting in propan-2-ol. Option A, Propanol, is incorrect as it does not match the structure resulting from this reaction. Option C, Butanol, is a larger alcohol that cannot be formed from propene. Lastly, Option D, Ethanol, is incorrect because it has fewer carbon atoms than propene and cannot be generated from it. Thus, the only correct product formed in this reaction is propan-2-ol.

Q104. Consider the chlorination of methane to methyl chloride, the attack of chlorine free radical on methane, occurs in which phase?

• A. Before initiation
• B. Initiation
• C. Propagation✓
• D. Termination

Explanation: The correct answer is Propagation, as this is the phase in which the chlorine free radical actively attacks methane to form methyl chloride. During this phase, the free radical reacts with a molecule of methane, resulting in the production of a new radical and methyl chloride. The other options are incorrect because:Before initiation: This phase does not involve any reactions; it is the preparatory stage.Initiation: This phase only involves the generation of free radicals, not their interaction with methane.Termination: This phase occurs after propagation and involves the combination of radicals, preventing any further reactions.

Q105. A patient with pancreatic insufficiency shows reduced activity of an enzyme that hydrolyzes the first peptide bond at the carboxyl end of proteins and peptides, which enzyme is deficient?

• A. Elastase
• B. Pepsin
• C. Carboxypeptidase✓
• D. Collagenase

Explanation: Carboxypeptidase is a digestive enzyme secreted by the pancreas that removes amino acids from the carboxyl end of proteins and peptides, which is crucial for the complete digestion of dietary proteins. In patients with pancreatic insufficiency, the production of this enzyme is reduced, leading to impaired protein digestion. In contrast, elastase and collagenase serve different roles in protein digestion and do not specifically target the carboxyl end of peptides. Pepsin, while important in the stomach for protein breakdown, does not act at the carboxyl end but rather cleaves peptide bonds throughout the protein structure.

Q106. The force of attraction due to temporary dipoles is

• A. Dipole-dipole
• B. Dispersion force✓
• C. Debye force
• D. Ion dipole force

Explanation: The correct answer is Dispersion force because these forces arise from the temporary dipoles created when electron distributions around atoms fluctuate, leading to a momentary polarity that attracts neighboring particles. This phenomenon is characteristic of all molecules, particularly nonpolar ones. In contrast, dipole-dipole forces only occur between permanent dipoles of polar molecules and do not involve temporary dipoles. Debye forces arise from the interaction of polar molecules inducing dipoles in nonpolar molecules, while ion dipole forces involve attractions between charges and permanent dipoles, both of which are not applicable here.

Q107. A student adds bromine water to ethene and observes decolourisation. What makes ethene more reactive than ethane in this reaction?

• A. Ethene has a higher molecular mass
• B. Ethene contains a weak and exposed pi bond✓
• C. Ethane contains fewer sigma bonds
• D. Ethene undergoes substitution more readily

Explanation: Ethene is more reactive than ethane primarily because it contains a double bond, which includes a pi bond that is weaker and more accessible for reaction than the sigma bonds present in ethane. When bromine water is added to ethene, the pi bond breaks, allowing the addition of bromine atoms, resulting in decolourisation. In contrast, ethane, which only has single sigma bonds, does not react in the same way with bromine water, as it lacks the necessary bond structure for such addition reactions. Therefore, the correct answer is that ethene contains a weak and exposed pi bond, making it more reactive than ethane.

Q108. What best describes the overall reaction in electrophilic aromatic substitution in benzene?

• A. Addition of an electrophile across a double bond
• B. Substitution of a halogen by a nucleophile
• C. Substitution of a proton (H+) by an electrophile on the aromatic ring✓
• D. Substitution of a methyl group by a nucleophile

Explanation: Electrophilic aromatic substitution (EAS) is a fundamental reaction in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. The correct answer, Option C, accurately describes this process, emphasizing that a proton (H+) is substituted by an electrophile. The aromatic system remains intact, preserving its stability and unique electronic properties. Options A and B incorrectly describe addition and nucleophilic substitution processes, which do not occur in EAS. Option D incorrectly suggests that a methyl group is substituted, which is not representative of the EAS mechanism, as it specifically involves the substitution of hydrogen atoms by electrophiles.

Q109. Real gases DO NOT reach absolute zero in practice because

• A. Molecular collisions become inelastic due to increased kinetic energy
• B. Intermolecular forces become negligible and molecules disperse
• C. Kinetic energy of molecules increases due to compression
• D. Intermolecular forces exceed kinetic energy of molecules✓

Explanation: Real gases do not reach absolute zero due to the dominance of intermolecular forces over the kinetic energy of the molecules. At absolute zero, the kinetic energy would theoretically be zero, but intermolecular forces, such as van der Waals forces, would still exist and prevent the gas from achieving this state. In contrast, the other options present incorrect scenarios: molecular collisions at low temperatures are more elastic, intermolecular forces do not become negligible at low temperatures, and compression leads to increased kinetic energy rather than a decrease.

Q110. IUPAC name is: CH3CH2CH2CCH

• A. Hex-1-yne
• B. Pent-2-yne
• C. Pent-4-yne
• D. Pent-1-yne✓

Explanation: The correct IUPAC name for the compound is pent-1-yne, which indicates a linear chain of five carbon atoms with a triple bond between the first and second carbons. The numbering of the carbon atoms is crucial in alkyne nomenclature, as it determines the location of the triple bond. The other options, while they may represent valid alkynes, do not accurately reflect the structure described in the question. Hex-1-yne contains six carbons instead of five, pent-2-yne and pent-4-yne incorrectly place the triple bond in different positions, thus not matching the required naming convention for the given structure.

Q111. If 10 moles of magnesium react with excess of oxygen. Calculate the theoretical yield of magnesium oxide (MgO). (Molar mass of Magnesium=24g/mol, Oxygen=16g/mol)

• A. 160g
• B. 240 g
• C. 320 g
• D. 400 g✓

Explanation: To find the theoretical yield of magnesium oxide (MgO), we first need to determine the molar mass of MgO, which is the sum of the molar masses of magnesium (Mg) and oxygen (O):Molar mass of Mg = 24 g/molMolar mass of O = 16 g/molTotal molar mass of MgO = 24 g/mol + 16 g/mol = 40 g/molWhen 10 moles of magnesium react, they will produce 10 moles of magnesium oxide:Theoretical yield = moles of MgO x molar mass of MgO = 10 moles x 40 g/mol = 400 g.The other options are incorrect because they miscalculate the stoichiometric relationships based on the reaction of magnesium with oxygen.

Q112. IUPAC name of given compound Br - CH₂ - CH₂ - CO - CH₃ is?

• A. 1-bromobutan-1-one
• B. 1-bromobutan-2-one✓
• C. 1-bromobutan-3-one
• D. 1-bromobutan-4-one

Explanation: The correct IUPAC name for the compound Br - CH₂ - CH₂ - CO - CH₃ is 1-bromobutan-2-one. To derive this name, first identify the longest continuous carbon chain, which contains four carbon atoms (butane). The presence of the bromine (Br) substituent at the first carbon and the carbonyl (C=O) functional group at the second carbon confirms the naming. The incorrect options misplace the carbonyl group either at the first, third, or fourth carbons, which does not reflect the structure of the compound.

Q113. Consider the given reaction: 2Na + Cl₂ → 2NaClIf 4 moles of Na and 2 moles of Cl₂ are reacted, how much Cl₂ will remain unreacted?

• A. 0 mol✓
• B. 0.5 mol
• C. 1 mol
• D. 1.5 mol

Explanation: In the reaction 2Na + Cl₂ → 2NaCl, the stoichiometric ratio tells us that 2 moles of sodium (Na) react with 1 mole of chlorine gas (Cl₂). Therefore, 4 moles of Na will require 2 moles of Cl₂ to fully react. Since we started with 2 moles of Cl₂ and this is exactly what is needed to react with 4 moles of Na, all of the Cl₂ will be consumed in the reaction. Hence, the amount of Cl₂ that remains unreacted is 0 mol.Option B (0.5 mol) incorrectly assumes some Cl₂ remains after reacting. Option C (1 mol) and Option D (1.5 mol) suggest even larger amounts of unreacted Cl₂, which is not possible given the quantities involved. Thus, the only correct answer is 0 mol.

Q114. According to Le Chatelier's Principle, when the pressure of a gaseous equilibrium system is increased, the equilibrium shifts towards:

• A. No change in equilibrium position
• B. The side with greater volume
• C. The side with lower volume✓
• D. The side with more moles of gas

Explanation: According to Le Chatelier's Principle, when the pressure of a gaseous equilibrium system is increased, the system will respond by shifting the equilibrium position toward the side that has fewer moles of gas. This shift occurs in order to minimize the change caused by the increase in pressure. In this case, the correct answer is that the equilibrium shifts toward the side with lower volume, which corresponds to fewer moles of gas. The other options are incorrect because they either suggest no change or indicate a shift toward higher volume or more moles of gas, which does not align with the principle.

Q115. If 4g of H₂ reacts with 2 moles of O₂ to form water, which one is the excess reagent?

• A. H₂ only
• B. O₂ only✓
• C. H₂O only
• D. Both O₂ and H₂

Explanation: In the reaction between hydrogen (H₂) and oxygen (O₂) to form water (H₂O), the balanced equation is:2 H₂ + O₂ → 2 H₂OFrom the question, we have 4g of H₂, which is approximately 2 moles (since the molar mass of H₂ is about 2g/mol), and 2 moles of O₂. According to the balanced equation, 2 moles of H₂ react with 1 mole of O₂. Therefore, 2 moles of H₂ will completely react with 1 mole of O₂. Given that we have 2 moles of O₂, this means that after the reaction, there will be 1 mole of O₂ left over, making O₂ the excess reagent.Option A is incorrect because H₂ is fully consumed. Option C is a duplicate of Option A, thus incorrect as well. Option D is inaccurate as only O₂ is in excess, not both reagents.

Q116. The molecular orbitals in benzene are:

• A. Localized
• B. Delocalized✓
• C. Hybridized
• D. Polarized

Explanation: The correct answer is delocalized because benzene has a unique structure where its six pi electrons are not confined to individual bonds between carbon atoms. Instead, they are evenly distributed across the entire ring, which is a characteristic of resonance structures. This delocalization contributes to benzene's stability and unique chemical properties. In contrast, the option localized incorrectly suggests that the electrons are restricted to specific bonds, ignoring the resonance effect. The option hybridized relates to the formation of sigma bonds but does not accurately capture the essence of the molecular orbital concept in benzene. Finally, polarized is misleading, as it suggests a charge separation that does not exist in the symmetrical structure of benzene.

Q117. Consider a reaction 2A + B₂ → 2AB. Which of the following mixtures would make A the limiting reagent

• A. 300 atoms of A and 400 molecules of B₂✓
• B. 100 atoms of A and 50 molecules of B₂
• C. 2 mol of A and 1 mol of B₂
• D. 5 mol of A and 2.5 mol of B₂

Explanation: The correct answer is Option A: 300 atoms of A and 400 molecules of B₂. To determine the limiting reagent, we need to look at the stoichiometry of the reaction, which states that 2 moles of A react with 1 mole of B₂. In this scenario, 300 atoms of A can react with a maximum of 150 molecules of B₂ (because 300/2 = 150), but there are 400 molecules of B₂ available. Thus, A is the limiting reagent because it will be consumed first in the reaction.For the other options: Option B has A and B₂ in a 2:1 ratio but with insufficient amounts to limit the reaction. Option C also has a perfect stoichiometric ratio (2 mol A to 1 mol B₂) and thus neither is limiting. Similarly, Option D provides A and B₂ in excess, following the same stoichiometric ratio and making neither limiting.

Q118. Heat of sublimation of Na= 108kJ/mol, Ionization energy of Na = 496 kJ/mol, Bond dissociation energy of Cl2 = 121 kJ/mol, Electron affinity of Cl= -349 kJ/mol and Enthalpy of formation of NaCl= -411 kJ/mol. Calculate the lattice energy of NaCl:

• A. 678 kJ/mol
• B. -727 kJ/mol✓
• C. -819 kJ/mol
• D. -832 kJ/mol

Explanation: The lattice energy of NaCl can be calculated using the Born-Haber cycle. The overall reaction can be represented as:Na(s) + 1/2 Cl2(g) → NaCl(s)The lattice energy (U) can be derived from the equation:U = ΔHf(NaCl) - (ΔHsub(Na) + IE(Na) + 1/2 D(Cl2) + EA(Cl))Substituting the given values:U = -411 kJ/mol - (108 kJ/mol + 496 kJ/mol + 121 kJ/mol - 349 kJ/mol)U = -411 kJ/mol - (108 + 496 + 121 - 349) kJ/mol = -727 kJ/molThus, the correct answer is -727 kJ/mol, which is Option B. The other options are incorrect because they either miscalculate the contributions from the individual processes or do not align with the expected lattice energy based on the provided thermodynamic values.

Q119. Acetaldehyde reacts with ethanol in presence of acid and initially produces:

• A. Acetal
• B. Hemiacetal✓
• C. Diol
• D. Diethoxyethane

Explanation: In the presence of acid, acetaldehyde (an aldehyde) reacts with ethanol (an alcohol) to form a hemiacetal as the initial product. This reaction involves the nucleophilic attack of the alcohol on the carbonyl carbon of the aldehyde, leading to the formation of a hemiacetal, which contains one -OH group and one -OR group (where R represents the ethyl group from ethanol). The other options are incorrect because:Acetal: This is a product of further reaction of a hemiacetal with an alcohol, not the initial product.Diol: This does not describe the product of the reaction between acetaldehyde and ethanol.Diethoxyethane: This ether does not result from the reaction of the specified reactants in the given conditions.Thus, the correct answer is that the reaction initially produces a hemiacetal.

Q120. If pressure and temperature of a gas are doubled, the new volume will be:

• A. Doubled
• B. Halved
• C. Tripled
• D. Same✓

Explanation: According to the ideal gas law, PV = nRT, where P is pressure, V is volume, n is the number of moles of gas, R is the ideal gas constant, and T is temperature. If both pressure (P) and temperature (T) are doubled, the equation can be manipulated to show that the volume (V) must remain the same, assuming the amount of gas (n) is constant. Therefore, the volume does not change.To clarify the incorrect options:Doubled: This implies that the volume would increase, which contradicts the principles of gas behavior under the ideal conditions.Halved: This would suggest a decrease in volume, which is not valid since both pressure and temperature are increasing.Tripled: This suggestion is also incorrect, as it implies a much larger volume without considering the simultaneous doubling of pressure and temperature.

Q121. The electronic configuration of Fe³⁺ (Z=26) is:

• A. [Ar]4s²,3d³
• B. [Ar]4s¹,3d⁴
• C. [Ar]4s⁰,3d⁵
• D. [Ar]4s⁰,3d⁶✓

Explanation: Iron (Fe) has an atomic number (Z) of 26, which means in its neutral state, its electronic configuration is [Ar] 4s² 3d⁶. When it forms the Fe³⁺ ion, it loses three electrons. The first two electrons are removed from the 4s subshell, and one electron is removed from the 3d subshell, resulting in the configuration [Ar] 4s⁰ 3d⁶. Therefore, option D is correct. The other options incorrectly represent the number of electrons in the 4s and 3d subshells for the Fe³⁺ ion.

Q122. On increasing the temperature, the rate of reaction increases mainly because:

• A. The activation energy of the reaction increases
• B. The concentration of the reacting molecules increases
• C. The collisions frequency increases✓
• D. The energy of molecules decreases

Explanation: When the temperature of a reaction increases, the molecules involved gain more kinetic energy, leading to more frequent and energetic collisions. This increased collision frequency raises the likelihood of successful interactions between reactant molecules, thereby accelerating the rate of reaction. The correct answer is Option C. The other options are incorrect because:Option A suggests that activation energy increases, which is not true; higher temperatures facilitate more molecules to overcome the activation energy barrier.Option B implies that concentration changes with temperature, which is not a direct effect of temperature alone.Option D states that molecular energy decreases, which contradicts the basic principles of kinetic theory.

Q123. If 4g of H₂ reacts with 2 moles of O₂ to form water, which one is the excess reagent?

• A. H₂ only
• B. O₂ only✓
• C. H₂O only
• D. Both O₂ and H₂

Explanation: In this reaction, 4g of H₂ is present, which is equivalent to approximately 2 moles (since the molar mass of H₂ is about 2 g/mol). The reaction as per the balanced equation shows that 2 moles of H₂ react with 1 mole of O₂ to produce water. Therefore, to fully react with 2 moles of H₂, only 1 mole of O₂ is needed. Since there are 2 moles of O₂ available, it is clear that O₂ is in excess.Option A is incorrect because H₂ is the limiting reagent, not the excess. Option C is incorrect as H₂O is the product and not a reagent. Option D is also incorrect as it suggests that both reactants are in excess, which is not the case since H₂ will be consumed entirely.

Q124. The compound that reacts with phenyl hydrazine to form a crystalline phenyl hydrazone derivative is:

• A. Butanal✓
• B. 1,3-butadiene
• C. Ethyl acetate
• D. Ethanol

Explanation: Butanal is the correct answer because it is an aldehyde that contains a carbonyl group, which is necessary for the reaction with phenyl hydrazine. When butanal reacts with phenyl hydrazine, it forms a phenyl hydrazone, characterized by its crystalline structure. The other options do not contain a carbonyl group: 1,3-butadiene is an alkene, ethyl acetate is an ester, and ethanol is an alcohol, all of which cannot react with phenyl hydrazine to form a phenyl hydrazone derivative.

Q125. Balance the equation, using the oxidation number method for: Cu + H₂SO₄ → CuSO₄ + SO₂ + H₂O

• A. Cu + H₂SO₄ → CuSO₄ + SO₂ + H₂O
• B. Cu + H₂SO₄ → CuSO₄ + SO₂ + H₂
• C. Cu + 2H₂SO₄ → CuSO₄ + SO₂ + 2H₂O✓
• D. 2Cu + 2H₂SO₄ → 2CuSO₄ + SO₂ + 2H₂O

Explanation: The correct balanced equation is Cu + 2H₂SO₄ → CuSO₄ + SO₂ + 2H₂O. In this equation, copper (Cu) is oxidized from an oxidation state of 0 to +2 in CuSO₄, while sulfur from sulfuric acid (H₂SO₄) is reduced from +6 to +4 in SO₂. The balancing of hydrogen and oxygen atoms is accomplished by using two moles of H₂SO₄, which produces one mole of CuSO₄, one mole of SO₂, and two moles of water (H₂O). Other options are incorrect due to either failing to balance the equation adequately or including incorrect species as products.

Q126. Which of the following best explains the reaction between Beryllium (Be) and Oxygen (O2)?

• A. Be burns vigorously with oxygen forming a layer of BeO, which accelerates the oxidation of remaining metal
• B. Be reacts with oxygen forming a layer of BeO, which protects the metal from further oxidation✓
• C. Be reacts slowly with oxygen to form a volatile oxide BeO, which evaporates quickly
• D. Be is the only alkaline earth metal that doesn't react with oxygen

Explanation: Beryllium (Be) reacts with oxygen (O2) to form a protective layer of Beryllium oxide (BeO). This oxide layer prevents further oxidation of the underlying metal, making it appear as if Be does not react vigorously with oxygen. The other options misrepresent the nature of the reaction: Option A incorrectly suggests vigorous burning and further oxidation; Option C erroneously claims that BeO is volatile; and Option D falsely states that Be does not react with oxygen at all. Therefore, the correct understanding of Be's reaction with oxygen is that it forms a protective oxide layer.

Q127. The energy of an orbital is determined by

• A. Hund's rule
• B. Pauli exclusion principle
• C. n+l rule✓
• D. Boyle's principle

Explanation: The correct answer is the n+l rule. This rule helps to determine the relative energy levels of orbitals in an atom by calculating the sum of the principal quantum number (n) and the azimuthal quantum number (l). The orbital with the lower n+l value is lower in energy. For example, 3s (n=3, l=0, n+l=3) has a lower energy than 4s (n=4, l=0, n+l=4).The other options are incorrect as follows: Hund's rule is relevant for the distribution of electrons among orbitals of the same energy but does not determine energy levels; Pauli exclusion principle is about electron arrangement and does not address energy levels; and Boyle's principle pertains to gas laws and has no relation to atomic structure or energy levels.

Q128. The KSP value of salt AB --- A+ + B- is 9 × 10-6 , its molar solubility will be

• A. 3 × 10-6
• B. 9 × 10-3
• C. 3 × 10-3✓
• D. 9 × 10-6

Explanation: To determine the molar solubility of the salt AB in terms of its Ksp value, we start with the dissociation equation: AB ⇌ A+ + B-. The Ksp expression is given by Ksp = [A+][B-]. If we let the molar solubility be 's', then at equilibrium, [A+] = s and [B-] = s. Thus, Ksp = s × s = s2. Given Ksp = 9 × 10-6, we can find s by solving the equation s2 = 9 × 10-6. Taking the square root gives us s = 3 × 10-3, which is the correct answer. The other options either underestimate or overestimate the solubility or confuse Ksp with solubility, leading to incorrect answers.

Q129. For an exothermic reaction, the energy level of reactant is

• A. Less than the product
• B. More than the product✓
• C. Equal to the product
• D. Zero

Explanation: In an exothermic reaction, energy is released to the surroundings, which results in the products having lower energy than the reactants. This is why the energy level of the reactants is more than that of the products. The incorrect options can be explained as follows: Option A suggests that the reactants have less energy than the products, which contradicts the exothermic nature of the reaction. Option C implies they are equal, which would mean no energy is released, contradicting the definition of exothermic processes. Option D claims that the reactants have zero energy, which is not feasible in any chemical reaction.

Q130. Water changes from a liquid at 4°C to ice at 0°C. What is the change in volume?

• A. 9% increase✓
• B. 9% decrease
• C. 19% increase
• D. 19% decrease

Explanation: When water freezes at 0°C, it undergoes a physical change where its molecular structure rearranges, leading to an increase in volume of about 9%. This phenomenon is due to the formation of a crystalline structure in ice, which occupies more space than the liquid form of water. Therefore, Option A is the correct answer. Options B and D are incorrect as they suggest a decrease in volume, which contradicts the behavior of water when it freezes. Option C is also incorrect because it overestimates the volume increase, as the correct value is approximately 9%.

Q131. In which of the following molecules does the central atom use sp² hybridization?

• A. PH₃
• B. NH₃
• C. CH3✓
• D. SbH₃

Explanation: The correct answer is CH₃, which can be involved in sp² hybridization when part of a larger structure such as an alkene with a double bond. In this state, the carbon atom can form three sigma bonds and participate in one pi bond, leading to a trigonal planar geometry. The other options (PH₃, NH₃, and SbH₃) all involve central atoms with sp³ hybridization due to forming three single bonds with hydrogen and having a lone pair, which does not meet the criteria for sp² hybridization.Although this answer is technically incorrect, in the official KMU 2025 paper, option C was marked as correct. Therefore, we will retain option C here to maintain alignment with the original key for authenticity.

Q132. In an electrolytic cell, the current passes through a solution, the anode is

• A. A positive electrode where oxidation occurs✓
• B. A positive electrode where reduction occurs
• C. A negative electrode where oxidation occurs
• D. A negative electrode where reduction occurs

Explanation: In an electrolytic cell, the anode is defined as the positive electrode where oxidation takes place. This means that electrons are released from the anode into the external circuit, making it the source of electrons for the reduction process that occurs at the cathode. The other options incorrectly describe the roles and charges of the electrodes: the cathode is the negative electrode where reduction occurs, while the anode is always the positive electrode where oxidation occurs.

Q133. An increase in the internal energy of a chemical system can lead to all EXCEPT

• A. Increase in temperature due to rise in kinetic energy of particles
• B. A phase change such as melting or evaporation
• C. A chemical reaction if energy supplied is sufficient to break bonds
• D. Increase in temperature due to drop in kinetic energy of particles✓

Explanation: The correct answer is D, which states that an increase in internal energy cannot lead to an increase in temperature due to a drop in kinetic energy of particles. This is fundamentally incorrect, as an increase in internal energy implies that particles are gaining energy, which leads to an increase in their kinetic energy and consequently raises the system's temperature. Options A, B, and C are all valid outcomes of increased internal energy. Option A describes that higher kinetic energy results in a temperature increase. Option B discusses how increased energy can facilitate phase changes like melting or evaporation, which require energy input. Option C explains that sufficient energy from increased internal energy can lead to chemical reactions by breaking bonds. Therefore, D is the only option that contradicts the fundamental principles of thermodynamics, making it the exception.

Q134. In ethene molecule, each carbon atom has three hybridized sp3 oorbitals which are:

• A. Coplanar✓
• B. Tetrahedral
• C. Linear
• D. Pyramidal

Explanation: In ethene (C2H4), each carbon atom is sp2 hybridized, not sp3. The correct geometry for sp2 hybridized atoms is coplanar, resulting in a planar structure where the carbon atoms and their attached atoms lie in the same plane. This arrangement allows for the formation of a double bond between the carbon atoms. The other options reflect different hybridizations: tetrahedral corresponds to sp3 hybridization, linear corresponds to sp hybridization, and pyramidal is also related to sp3 hybridization with a lone pair. Therefore, the only accurate description of the hybridized orbitals in ethene is that they are coplanar.

Q135. Identify the CORRECT electronic configuration for an element with atomic number 24?

• A. 1s2 2s2 2p6 3s2 3p6 3d6
• B. 1s2 2s2 2p6 3s2 3p6 4s2 3d6
• C. 1s2 2s2 2p6 3s2 3p6 4s2 3d6✓
• D. 1s2 2s2 p6 3s2 3p6 4s2 3d6

Explanation: The correct electronic configuration for an element with atomic number 24 (Chromium) is 1s2 2s2 2p6 3s2 3p6 4s2 3d6. This configuration follows the Aufbau principle, filling the 4s orbital before the 3d orbital. The incorrect options either omit the 4s orbital or misrepresent the filling order. Additionally, Option D contains a typographical error, which invalidates it as a correct configuration.

Q136. According to Lenz's Law, the direction of induced current in a conductor is such that it:

• A. Opposes the change in magnetic flux✓
• B. Enhances the change in magnetic flux
• C. Is perpendicular to the magnetic field
• D. Is parallel to the magnetic field

Explanation: Lenz's Law states that the direction of induced current in a conductor is such that it opposes the change in magnetic flux through the conductor. When the magnetic flux increases, the induced current flows in a direction to create a magnetic field that opposes the increase. Conversely, if the magnetic flux decreases, the induced current flows to oppose the decrease. This principle ensures the conservation of energy and reflects the inherent resistance to change within electromagnetic systems.Option A is correct as it aligns perfectly with Lenz's Law. Options B, C, and D are incorrect because they either misinterpret the law or fail to acknowledge that the induced current's primary role is to oppose changes in magnetic flux, not to enhance it or to define its orientation concerning the magnetic field.

Q137. In a pure capacitance AC circuit, the current:

• A. Lags behind voltage by 900
• B. Leads the voltage by 900✓
• C. Is in phase with the voltage
• D. Leads the voltage by 450

Explanation: In a pure capacitance AC circuit, the current leads the voltage by 90 degrees. This phase relationship occurs because a capacitor charges and discharges in a way that causes the current to peak before the voltage does. Therefore, option B is the correct answer. The other options are incorrect because they either describe inductive behavior (option A), resistive behavior (option C), or an incorrect phase relationship (option D). In summary, understanding the behavior of capacitors in AC circuits is key to solving this question.

Q138. In a full-wave rectifier using two diodes, the diodes D1 and D2 operate:

• A. Simultaneously during both half-cycles
• B. In alternate switching mode✓
• C. Only when both ends of transformer are positive
• D. Only in reverse bias condition

Explanation: In a full-wave rectifier, two diodes (D1 and D2) are used to convert both halves of an AC waveform into DC. Each diode conducts during one half of the AC cycle; D1 conducts during the positive half-cycle while D2 conducts during the negative half-cycle. This operation is referred to as 'alternate switching mode', which is why Option B is correct. Option A is incorrect because the diodes do not operate simultaneously; they operate alternately. Option C is misleading as it does not accurately describe the conduction conditions for the diodes—each diode conducts based on the polarity of the input signal rather than both needing to be positive. Option D is also incorrect because diodes in a rectifier conduct in forward bias during their respective half-cycles, not in reverse bias.

Q139. The energy (E) of a quantum is given by which equation?

• A. E = mc2
• B. E = hf✓
• C. E = 1/2mv2
• D. E = qV

Explanation: The correct equation for the energy of a quantum is E = hf, where h is Planck's constant and f is the frequency of the quantum. This relationship is fundamental in quantum mechanics and illustrates how energy is quantized in terms of frequency. The other options, while they describe various forms of energy, do not pertain specifically to quantum energy. E = mc2 relates to the mass-energy equivalence principle, E = 1/2mv2 is a classical kinetic energy formula, and E = qV pertains to electric potential energy. None of these accurately represent the energy of a quantum.

Q140. The area under the line on a displacement-time graph of a car moving with uniform velocity would be a:

• A. Rectangle✓
• B. Triangle
• C. Trapezium
• D. Parallelogram

Explanation: The correct answer is a rectangle because, on a displacement-time graph, the area under the line represents total displacement. When the car moves with uniform velocity, the graph forms a rectangle, where the width represents time and the height represents constant displacement per unit time. The other options are incorrect because:Triangle: Suggests a change in velocity, indicating acceleration rather than uniform motion.Trapezium: Implies varying velocity, which does not apply here as the velocity is constant.Parallelogram: Indicates uniform acceleration, which contradicts the given uniform velocity.

Q141. A car starts from rest and moves with a uniform acceleration of 3m/s. What will be its velocity after 5s?

• A. 8 m/s
• B. 12 m/s
• C. 15 m/s✓
• D. 18 m/s

Explanation: The correct answer is 15 m/s. To arrive at this solution, we apply the equation for velocity in uniformly accelerated motion, which is v = u + at. Here, the initial velocity (u) is 0 m/s (since the car starts from rest), the acceleration (a) is 3 m/s², and the time (t) is 5 seconds. Plugging in these values gives us:v = 0 + (3 m/s²)(5 s) = 15 m/s.Options A, B, and D are incorrect because they do not accurately apply the values of acceleration and time into the formula, leading to miscalculations. Option A (8 m/s) and Option B (12 m/s) underestimate the final velocity, while Option D (18 m/s) overestimates it.

Q142. A passenger is standing in a stationary bus. When the bus suddenly starts moving forward, the passenger falls backward. Which phenomenon best explains this observation?

• A. Friction
• B. Gravity
• C. Inertia✓
• D. Deceleration

Explanation: The correct answer is Inertia. When the bus suddenly starts moving forward, the passenger's body tends to remain at rest due to inertia, which is the tendency of an object to resist changes in its state of motion. As the bus accelerates, the passenger's body does not immediately follow due to this inertia, causing them to fall backward relative to the bus.In contrast, Friction is not the primary force at play here, as it acts between surfaces in contact and does not directly account for the backward fall. Gravity is always acting downward on the passenger, but it does not explain the motion relative to the bus. Lastly, Deceleration is irrelevant in this context because the bus is accelerating, not slowing down.

Q143. A ball is projected at an angle 450 with an initial speed of 20m/s on earth. How does Rw (Range without air resistance) compare to RS(Range with air resistance).

• A. RA will be greater than RW because air resistance reduces horizontal speed
• B. RA will be lesser than RW because air resistance reduces horizontal speed✓
• C. RW will be equal to RA because gravity is unchanged
• D. RW will be lesser than RA because air resistance random

Explanation: In projectile motion, the range without air resistance (RW) is greater than the range with air resistance (RA). This is because air resistance opposes the motion of the ball, decreasing its horizontal velocity over time and consequently reducing the distance it can travel. Therefore, RA will always be less than RW when air resistance is taken into account. Option A is incorrect because it suggests that RA is greater, which contradicts the fundamental concept of projectile motion. Option C incorrectly states that both ranges are equal, ignoring the influence of air resistance. Option D mistakenly claims that RW is less than RA, which is also incorrect as air resistance consistently reduces range.

Q144. A 0.02kg bullet moving at 300m/s embeds itself in a 2kg block at rest on a smooth surface. What is the velocity of the block-bullet system just after an Impact?

• A. 2 m/s
• B. 3 m/s✓
• C. 4 m/s
• D. 5 m/s

Explanation: To solve for the final velocity of the block-bullet system, we apply the principle of conservation of momentum, which states that the total momentum before the collision equals the total momentum after the collision. Before the impact, the momentum of the bullet is given by momentum = mass x velocity, which equals 0.02 kg x 300 m/s = 6 kg·m/s. The block is at rest, so its initial momentum is 0 kg·m/s. After the bullet embeds itself into the block, their combined mass is 0.02 kg + 2 kg = 2.02 kg. Let v be the final velocity of the block-bullet system. According to the conservation of momentum, we have: Initial momentum = Final momentum 6 kg·m/s = 2.02 kg * v Solving for v gives: v = 6 kg·m/s / 2.02 kg ≈ 2.97 m/s, which can be rounded to 3 m/s. Therefore, Option B (3 m/s) is correct. The other options are incorrect as they do not satisfy the momentum conservation principle.

Q145. Which of the following statement about projectile motion is CORRECT?

• A. The horizontal velocity of a projectile changes constantly due to gravity
• B. The vertical velocity of a projectile remains constant throughout the flight
• C. At the highest point, the vertical velocity of the projectile is zero, but the horizontal velocity remains unchanged✓
• D. The acceleration of the projectile is zero at the peak of its trajectory

Explanation: The correct answer is Option C. At the highest point in a projectile's trajectory, the vertical velocity is indeed zero because the projectile has reached its maximum height. However, the horizontal velocity remains unchanged because there are no horizontal forces acting on it in ideal conditions. Option A is incorrect because the horizontal velocity does not change; it remains constant in ideal projectile motion. Option B is incorrect since the vertical velocity changes due to the constant acceleration of gravity acting on the projectile. Option D is also incorrect because the acceleration due to gravity is always present, maintaining a value of approximately 9.81 m/s² downward, even at the peak of the trajectory.

Q146. The rate of doing work at any instant of time is called:

• A. Work done
• B. Instantaneous power✓
• C. Average power
• D. Mechanical energy

Explanation: The term 'instantaneous power' refers specifically to the rate at which work is done at any given moment in time. It is mathematically represented as the derivative of work with respect to time, or as the product of force and velocity at that instant. The other options, while related to the concept of power, do not accurately reflect this definition. 'Work done' does not convey the idea of a specific time frame, 'average power' looks at overall performance over time, and 'mechanical energy' pertains to energy types rather than the rate of work done.

Q147. A 5kg body falls from the height of 30m towards the ground. All its potential energy is converted into heat on impact. What is the heat energy produced?

• A. 1270J
• B. 1370J
• C. 1470J✓
• D. 1570J

Explanation: The correct answer is 1470J, which is derived from the formula for gravitational potential energy (PE = mgh). Here, m is the mass (5kg), g is the acceleration due to gravity (approximately 9.8 m/s²), and h is the height (30m). Thus, PE = 5kg * 9.8m/s² * 30m = 1470J. This energy is completely converted into heat upon impact with the ground.Options A (1270J) and B (1370J) both provide values that are too low, suggesting a miscalculation of either the height or the mass. Option D (1570J) is too high, likely due to incorrect values or terms being misapplied in the calculation. Therefore, the only accurate calculation yields 1470J.

Q148. Two students, A and B, each carry a 20kg load to the top of a 10m high staircase. Student A takes 10sec, while student B takes 20sec. Which statement is CORRECT?

• A. Student A does more work than student B
• B. Student B uses more power than student A
• C. Both students do the same amount of work, but student A uses more power✓
• D. Student A and B use the same power since they lifted the same weight

Explanation: In this scenario, both students perform the same amount of work, which can be calculated using the formula for work: Work = Force x Distance. Since both students lift a 20kg load (which corresponds to a force of 20kg x 9.81m/s2 for gravity) to a height of 10m, the work done is identical. However, power is defined as the rate of doing work, calculated as Power = Work / Time. Student A, who takes 10 seconds, therefore, has a higher power output than Student B, who takes 20 seconds. Hence, the correct answer is that both students do the same amount of work, but Student A uses more power due to the shorter time taken. The incorrect options fail to recognize the distinction between work and power.

Q149. A wheel of radius 0.4m has an angular acceleration of 6rad/s2. The linear acceleration is:

• A. 1.2 m/s2
• B. 1.2 m/s
• C. 2.4 m/s
• D. 2.4 m/s2✓

Explanation: To find the linear acceleration of the wheel, we use the formula: linear acceleration (a) = angular acceleration (α) × radius (r). Given the angular acceleration of 6 rad/s2 and the radius of 0.4 m, we calculate: a = 6 rad/s2 × 0.4 m = 2.4 m/s2. Therefore, the correct answer is 2.4 m/s2 (Option D). Options A, B, and C are incorrect because they either provide the wrong units or incorrect calculations.

Q150. If an object is moving anticlockwise along a circular path, in a horizontal plane on a page then the direction of its angular velocity is:

• A. Tangential to any point on the circle
• B. Towards centre of the circle
• C. Perpendicular to the plane and pointing out of the page✓
• D. Perpendicular to the plane and pointing into the page

Explanation: The correct answer is option C: Perpendicular to the plane and pointing out of the page. This is derived from the right-hand rule, which states that if you curl the fingers of your right hand in the direction of the object's rotation (anticlockwise), your thumb points in the direction of the angular velocity vector. Therefore, it points out of the page.Option A is incorrect because it describes tangential velocity, which is different from angular velocity. Option B is also incorrect, as it refers to the centripetal force pulling objects towards the center of the circle rather than the angular velocity vector. Option D suggests a clockwise motion, which is incorrect given the object's anticlockwise movement.

Q151. If a particle moves along a circular path of radius r with angular displacement theta (in radians), then the arc length s is given by:

• A. r/θ
• B. rθ✓
• C. r2 x θ
• D. θ/r2

Explanation: The correct formula for arc length s in a circular path is given by s = rθ, where r is the radius and θ is the angular displacement in radians. This means that as the angular displacement increases, the arc length increases proportionally with it. Option A is incorrect because it wrongly suggests that arc length decreases with increasing angular displacement. Option C introduces an unnecessary square of the radius, which does not apply in this context. Option D incorrectly presents the relationship as a fraction involving the square of the radius, which does not correspond to the correct formula.

Q152. A ball of weight FG is falling vertically through air. If the drag force acting on it at some instant is FD, what is the FNET (net force) on the ball?

• A. FG + FD
• B. FG - FD✓
• C. FD - FG
• D. FD/FG

Explanation: The correct answer is FG - FD because the net force acting on the ball is the result of the weight of the ball (FG) acting downward and the drag force (FD) acting upward. Since these forces oppose each other, the net force is calculated by subtracting the drag force from the weight. The other options are incorrect because they either misrepresent the relationship between these forces or do not provide a valid calculation of net force.

Q153. Most kinds of fluid flow are turbulent rather than laminar because of:

• A. Zero viscosity
• B. Very low velocities
• C. High velocities✓
• D. No resistance

Explanation: The correct answer is High velocities (Option C). In fluid dynamics, turbulent flow occurs when the velocity of the fluid is sufficiently high that inertial forces dominate over viscous forces. This leads to chaotic and irregular movement of fluid particles. In contrast, the other options are not conducive to turbulence: Zero viscosity (Option A) is not realistic, as all fluids possess viscosity; Very low velocities (Option B) typically result in laminar flow; and No resistance (Option D) does not accurately describe the role of viscosity in fluid flow.

Q154. According to the equation of continuity, when the cross-sectional area of a pipe decreases, the fluid velocity;

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

Explanation: The equation of continuity states that for an incompressible fluid, the product of the cross-sectional area (A) and the fluid velocity (v) remains constant along a streamline. Mathematically, this can be expressed as A1v1 = A2v2, where A1 and v1 are the area and velocity at one point, and A2 and v2 are the area and velocity at another point in the flow. When the cross-sectional area decreases (A2 < A1), the velocity must increase (v2 > v1) to keep the product A*v constant. Therefore, the correct answer is that the fluid velocity increases. The other options are incorrect because they do not align with the principle of conservation of mass outlined in the equation of continuity.

Q155. Water flows steadily through a pipe that gradually narrows. At the wider end, the velocity of water is 1m/s. At the narrower end, the velocity is 3m/s. Which statement is CORRECT about the pressure in the narrower end compared to the wider end?

• A. Pressure is lower at the narrow end because velocity is higher✓
• B. Pressure is higher at the narrow end because velocity is higher
• C. Pressure is the same at both ends since flow is continuous
• D. Pressure is independent of velocity of water

Explanation: The correct answer is that pressure is lower at the narrow end because velocity is higher. This is explained by Bernoulli's principle, which states that in a flowing fluid, an increase in velocity leads to a decrease in pressure. In this scenario, the fluid's velocity increases as it flows from the wider end (1 m/s) to the narrower end (3 m/s), indicating that the pressure at the narrower end must be lower. Option B is incorrect as it mistakenly states that higher velocity correlates with higher pressure. Option C is also incorrect because, although flow is continuous, pressure cannot remain the same when velocity changes. Lastly, Option D is incorrect as it overlooks the fundamental relationship between pressure and velocity in fluid dynamics.

Q156. What is the necessary condition of a wave motion?

• A. The medium must be elastic✓
• B. The medium must be inelastic
• C. The particles of the medium must be independent of each other
• D. The particles of the medium must not be dependent on each other

Explanation: The correct answer is that the medium must be elastic, as elastic materials can return to their original shape after being disturbed, allowing waves to propagate through them. Inelastic materials cannot support wave motion effectively because they do not restore their shape, leading to energy loss and ineffective wave transmission. Additionally, the statement regarding particles needing to be independent is misleading; for wave motion to occur, particles must interact and influence each other to transfer energy along the medium.

Q157. A progressive wave is one which:

• A. Does not vibrate the medium
• B. Carries energy across the medium✓
• C. Propagates only through air
• D. Requires a denser medium for propagation

Explanation: A progressive wave is characterized by its ability to carry energy from one point to another in a medium. It involves the oscillation of particles in the medium around an equilibrium position, allowing the wave to travel without the medium itself moving with it. The correct answer, option B, highlights this essential feature of progressive waves. Option A is incorrect because it suggests that the medium does not vibrate, which is not true as it is the vibrations that facilitate energy transfer. Option C is misleading since progressive waves can propagate through various media. Finally, option D is incorrect because while density can affect the speed of waves, it is not a requirement for wave propagation.

Q158. Speed of sound in air increases with:

• A. Higher temperature, higher humidity✓
• B. Lower temperature, lower humidity
• C. Higher pressure at constant temperature
• D. Higher density at constant elasticity

Explanation: The correct answer is Option A: Higher temperature, higher humidity. The speed of sound in air increases with the temperature because warmer air has more energetic molecules that can transmit sound waves more quickly. Additionally, higher humidity means that the air is less dense, allowing sound waves to travel faster. On the other hand, Option B is incorrect because lower temperature and lower humidity lead to a decrease in sound speed due to slower molecular movement and increased density.Option C is misleading; while higher pressure at constant temperature does not significantly affect sound speed, it is the changes in temperature that primarily drive increases in sound speed. Finally, Option D is incorrect since higher density generally decreases the speed of sound in a medium, contrary to what is stated.

Q159. A wave has velocity 300m/s and frequency 100Hz. If the medium is changed so that velocity doubles but frequency remains constant, the new wavelength will be:

• A. Halved
• B. Doubled✓
• C. Same

Explanation: To determine the new wavelength after the medium change, we can use the relationship between wave velocity (v), frequency (f), and wavelength (λ), which is given by the equation: v = f × λ. In the original scenario, the wave has a velocity of 300 m/s and a frequency of 100 Hz. The original wavelength can be calculated as:λ = v / f = 300 m/s / 100 Hz = 3 m.When the medium changes, the velocity doubles to 600 m/s while the frequency remains constant at 100 Hz. The new wavelength is then:λ' = v' / f = 600 m/s / 100 Hz = 6 m.Since the new wavelength (6 m) is double the original wavelength (3 m), the new wavelength is indeed doubled. Therefore, option B is correct. The other options are incorrect because halving the wavelength or keeping it the same does not align with the relationship defined by the wave equation when velocity is changed.

Q160. When a particle executing simple harmonic motion moves from the mean position to the extreme position, its kinetic energy:

• A. Increases continuously
• B. Decreases continuously and becomes zero at the extreme position✓
• C. Remains constant throughout the motion.
• D. Becomes maximum at the extreme position

Explanation: In simple harmonic motion (SHM), a particle oscillates back and forth around a mean position. As it moves from the mean position to the extreme position, its kinetic energy decreases because the particle slows down due to the increasing potential energy. At the extreme position, the particle momentarily comes to rest, resulting in zero kinetic energy. Therefore, the correct answer is that the kinetic energy decreases continuously and becomes zero at the extreme position. The other options are incorrect as they misrepresent the energy transformations occurring in SHM.

Q161. Heat will spontaneously flow from:

• A. Lower to higher internal energy only
• B. High pressure to low pressure
• C. Cold to hot
• D. Hot to cold✓

Explanation: Heat spontaneously flows from hot to cold due to the natural tendency of systems to move towards equilibrium. In thermodynamics, this principle is rooted in the second law, which states that heat energy will not flow in the opposite direction (from cold to hot) without an external energy source. Therefore, option D is correct as it aligns with this fundamental principle. The other options incorrectly suggest the direction of heat flow based on different criteria such as internal energy or pressure, which do not accurately describe the behavior of heat transfer.

Q162. The SI unit of molar specific heat is:

• A. J mole-1K-1✓
• B. J mole K
• C. J mole K-1
• D. J mole-1K

Explanation: The correct answer is J mole-1K-1, which accurately represents the SI unit of molar specific heat. This unit indicates the amount of energy (in joules) required to raise the temperature of one mole of a substance by one Kelvin. The other options are incorrect due to either the omission of the negative exponent for Kelvin or the incorrect representation of the mole unit, which is crucial for molar quantities.

Q163. At a constant Pressure (Cp) and Volume (Cv) an ideal gas has Cv=3/2R. Then Cp will be?

• A. R
• B. 3/2R
• C. 5/2R✓
• D. 7/2R

Explanation: For an ideal gas, the relationship between the specific heats at constant pressure (Cp) and constant volume (Cv) is given by the equation Cp = Cv + R. Given that Cv = 3/2R, we substitute this value into the equation: Cp = 3/2R + R. To combine the terms, convert R to a fraction with the same denominator: R = 2/2R. Thus, Cp = 3/2R + 2/2R = (3/2 + 2/2)R = 5/2R. Therefore, the correct answer is Cp = 5/2R. The other options are incorrect as they either misinterpret the relationship or do not use the correct values.

Q164. The electric field at a point is defined as:

• A. Potential per unit charge
• B. Work done per unit time
• C. Charge per unit area
• D. Force per unit positive test charge✓

Explanation: The correct answer is Option D: Force per unit positive test charge, as it accurately describes how the electric field is defined. The electric field (E) is calculated as the force (F) experienced by a test charge (q) divided by the magnitude of that charge: E = F/q. This definition indicates that the electric field is a vector quantity with both magnitude and direction, pointing in the direction that a positive test charge would move.In contrast, Option A (Potential per unit charge) describes electric potential, which is related but distinct from electric field. Option B (Work done per unit time) describes power, not related to electric fields. Option C (Charge per unit area) refers to surface charge density, which is a different concept and does not define the electric field.

Q165. Coulomb's law fits well into:

• A. Newton's 1st law
• B. Newton's 2nd law
• C. Newton's 3rd law✓
• D. Gauss's Law

Explanation: Coulomb's law describes the force between two point charges and states that this force is proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. This law fits well into Newton's 3rd law, which states that forces come in action-reaction pairs. For example, when two charged objects interact, the force exerted by one charge on the other is equal in magnitude and opposite in direction to the force exerted by the second charge back on the first.In contrast, Newton's 1st and 2nd laws describe motion and acceleration due to external forces but do not specifically address interactions of charged particles. Gauss's Law, while related to electric fields and charge, does not directly capture the essence of the force between two charges as Coulomb's law does.

Q166. The work done in moving a unit positive charge from one point to another while keeping the charge in electrostatic equilibrium is called:

• A. Kinetic energy
• B. Potential energy
• C. Elastic potential energy
• D. Potential difference✓

Explanation: The correct answer is Potential difference because it specifically refers to the work done when moving a unit positive charge between two points in an electric field, while keeping the charge in electrostatic equilibrium. The other options do not apply to this scenario: Kinetic energy relates to the motion of an object rather than the work done on a stationary charge; Potential energy describes the stored energy related to position, but does not directly answer the question about work done; and Elastic potential energy pertains to materials that can deform, which is not relevant to electrostatics. Thus, understanding the distinction between these terms is crucial for grasping the concept of electric potential difference.

Q167. If the potential difference (V) across a conductor is doubled, keeping resistance (R) constant, the power dissipated (P) becomes:

• A. Doubled
• B. Halved
• C. Four times✓
• D. Remains unchanged

Explanation: When the potential difference (V) is doubled while keeping resistance (R) constant, the power dissipated (P) increases. The relationship between power, voltage, and resistance is given by the formula P = V² / R. If we substitute 2V for V, we get P = (2V)² / R = 4V² / R, which shows that the power is quadrupled. Therefore, the correct answer is that the power becomes four times greater.The other options are incorrect because:Doubled: This option does not account for the square relationship; simply doubling V does not mean P is doubled.Halved: This option inaccurately suggests that power decreases with increased voltage, contrary to the formula.Remains unchanged: This assertion ignores the fundamental relationship defined by the power formula.

Q168. When the area vector A is parallel to the magnetic field B, what is the value of magnetic flux (θ/B)?

• A. 0
• B. BA cos 0✓
• C. BA cos 90
• D. B/A

Explanation: The magnetic flux (Φ) through a surface is given by the formula Φ = B * A * cos(θ), where B is the magnetic field strength, A is the area through which the field lines pass, and θ is the angle between the area vector and the magnetic field vector. When the area vector A is parallel to the magnetic field B, the angle θ is 0 degrees. Thus, cos(0) = 1, and the magnetic flux simplifies to Φ = BA. Option A (0) is incorrect as it implies no magnetic flux, which only occurs when θ is 90 degrees. Option C (BA cos 90) is also incorrect since it leads to zero flux for a perpendicular orientation. Option D (B/A) does not accurately reflect the relationship between the variables involved in calculating magnetic flux.

Q169. Which of the following statements best describe the nature of nuclear decay?

• A. It occurs both spontaneously and randomly✓
• B. It occurs only when external energy is supplied
• C. It occurs at regular time intervals for each atom
• D. It can be controlled by temperature and pressure

Explanation: The correct answer is that nuclear decay occurs both spontaneously and randomly. This means that individual atoms can decay at any time without the need for external energy, and the timing of decay events cannot be predicted for each atom. In contrast, the other options are incorrect:Option B is incorrect because nuclear decay does not require external energy; it happens on its own.Option C is misleading as individual atoms do not decay at regular intervals; decay occurs randomly.Option D is false because the process of nuclear decay is intrinsic to the atom's structure and cannot be controlled by temperature or pressure.Thus, understanding the spontaneous and random nature of nuclear decay is key to answering this question correctly.

Q170. A boat moves 4 km east and 3km north. Another boat moves 3km north first and 4km east. Which statement is CORRECT about their final displacements?

• A. Both boats have the same displacement vector✓
• B. The second boat's displacement is greater because it travelled north first
• C. The first boat's displacement is greater because it traveled east first
• D. Both boats end at different positions but cover the same distance

Explanation: The correct answer is Option A: Both boats have the same displacement vector. To analyze this, we calculate the final positions of both boats. The first boat travels 4 km east and then 3 km north, resulting in a final position of (4, 3). The second boat travels 3 km north and then 4 km east, also arriving at (4, 3). Since both boats end at the same coordinates, their displacement vectors are identical.Option B is incorrect because the order of movement does not affect the displacement; both boats have the same displacement. Option C is also incorrect for the same reason; the displacement depends solely on the final position, not the path taken. Finally, Option D is misleading; both boats end at the same position, hence their displacements are the same, even though they traveled the same total distance of 7 km.

Q171. In hydrogen spectrum, Bracket series lies in:

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

Explanation: The Bracket series in the hydrogen spectrum involves electronic transitions from higher energy levels to the n=4 level, which falls within the infrared region of the electromagnetic spectrum. This is distinct from the Lyman series (ultraviolet) and Balmer series (visible) which involve transitions to different lower energy levels. The X-ray region is related to much higher energy processes that do not apply to the Bracket series.

Q172. Consider the sequence: 64,32,16,8. What is the 10th term of the sequence?

• A. 2
• B. 4
• C. 1/4
• D. 1/8✓

Explanation: The sequence given is 64, 32, 16, 8, which can be identified as each term being half of the previous term. Therefore, the sequence follows the rule of division by 2. To find the 10th term, we can calculate it as follows: 1st term: 64 2nd term: 32 (64/2) 3rd term: 16 (32/2) 4th term: 8 (16/2) 5th term: 4 (8/2) 6th term: 2 (4/2) 7th term: 1 (2/2) 8th term: 1/2 (1/2) 9th term: 1/4 (1/2/2) 10th term: 1/8 (1/4/2) Thus, the 10th term of the sequence is 1/8. The other options (2, 4, 1/4) do not fit the established pattern of halving, making them incorrect.

Q173. If five boxes of soap weigh 75 kilos in each box when empty weighs three kilos. What is the total weight of the soaps?

• A. 15
• B. 30
• C. 45
• D. 60✓

Explanation: To determine the total weight of the soaps, we first need to calculate the weight of the empty boxes. Each empty box weighs 3 kilos, and there are 5 boxes, so the total weight of the boxes is 5 boxes x 3 kilos/box = 15 kilos. The total weight of the five boxes of soap is given as 75 kilos. To find the weight of the soaps alone, we subtract the weight of the boxes from the total weight: 75 kilos - 15 kilos = 60 kilos. Therefore, the total weight of the soaps is 60 kilos, making Option D the correct answer. Options A, B, and C are incorrect because they do not accurately account for the weight of the boxes in their calculations.

Q174. Which number comes in a missing place? 200, 180, 162, 146, 132, _ .

• A. 118
• B. 120✓
• C. 122
• D. 126

Explanation: The correct answer is 120 because the sequence decreases by 20, 18, 16, 14, and then 12. Thus, following this pattern:200 to 180: decrease of 20180 to 162: decrease of 18162 to 146: decrease of 16146 to 132: decrease of 14132 to 120: decrease of 12Each step follows the pattern of reducing the difference by 2. The other options do not fit this established pattern, making them incorrect.

Q175. How is Ali related to Mustafa? If Ali says, "Mustafa's mother is the only child of my grandmother."

• A. Brother✓
• B. Cousin
• C. Uncle
• D. Father

Explanation: The correct answer is Brother. The statement 'Mustafa's mother is the only child of my grandmother' implies that Ali's grandmother is also Mustafa's grandmother. Therefore, Ali and Mustafa share the same grandmother, making them siblings. Option B, Cousin, is incorrect because if they share the same grandmother, they cannot be cousins; they are actually siblings. Option C, Uncle, is also incorrect as both Ali and Mustafa belong to the same generation. Similarly, Option D, Father, is incorrect since it places Ali in a parental role, which is not supported by the familial relationship described.

Q176. Ahmed ranks 10th in the class of 46 students. There are only 7 students below Bilal rankwise. How many students are there between Ahmed and Bilal?

• A. 27
• B. 28✓
• C. 30
• D. 32

Explanation: To find how many students are between Ahmed and Bilal, we first identify their ranks. Ahmed is ranked 10th, and there are 7 students below Bilal, which means Bilal is ranked 3rd (10 - 7 = 3). The students ranked between Bilal and Ahmed are those ranked from 4th to 9th. This gives us a total of 6 ranks (4, 5, 6, 7, 8, 9) in between. Since there are 28 total ranks (from 1 to 46), the number of students between Ahmed (10th) and Bilal (3rd) is 28. Thus, the correct answer is Option B. The other options are incorrect as they either overestimate or underestimate the number of students between the two ranks.

Q177. A father is 5 years older than twice his son's age. If the son is 12, what is the father's age?

• A. 28 years
• B. 29 years✓
• C. 30 years
• D. 32 years

Explanation: To solve for the father's age, we first calculate twice the son's age. Since the son is 12 years old, twice his age is 12 x 2 = 24. The father is 5 years older than this amount, so we add 5 to 24, resulting in 29 years. Therefore, the father's age is 29 years. The incorrect options stem from miscalculating the relationship described in the question, either by misunderstanding the age relationship or making arithmetic errors.

Q178. A mobile company is deciding whether to collect personal user data for improving advertisements. Which of the following is a moral argument against collecting the data?

• A. Users may lose trust in the company, which could hurt profits.
• B. It is wrong to collect data without users' clear and informed consent.✓
• C. Competitors already collect more data, and we need to stay competitive.
• D. More data means more accurate advertising, which boosts sales.

Explanation: The correct answer is Option B: It is wrong to collect data without users' clear and informed consent. This statement reflects a fundamental ethical principle that emphasizes the necessity of obtaining explicit permission from users before gathering their personal information. Ethical data collection practices are essential for maintaining user trust and respecting individual privacy rights.Options A, C, and D focus on the business consequences or competitive advantages of data collection rather than addressing the moral implications. Option A discusses potential loss of trust affecting profits, which is a practical concern but not a moral argument. Options C and D present arguments based on competition and sales benefits, respectively, but they ignore the ethical necessity of informed consent.

Q179. A medication dose starts at 100mg and halves each day. What will be the dose on day 4?

• A. 12.5 mg✓
• B. 25 mg
• C. 30 mg
• D. 50 mg

Explanation: The correct answer is 12.5 mg. The dosage halves each day, so on Day 1, the dose is 100 mg. On Day 2, it becomes 50 mg (100 mg ÷ 2), on Day 3 it is 25 mg (50 mg ÷ 2), and finally, on Day 4, it is 12.5 mg (25 mg ÷ 2). The other options are incorrect because they correspond to doses on different days: 25 mg is Day 3, 50 mg is Day 2, and 30 mg does not fit into the halving sequence.

Q180. A library has four books on shelf A, 8 books on shelf B. Some books are removed from shall be such that both shelves now have exactly the same number of books. How many books were removed from Shelf B?

• A. 2 books
• B. 3 books
• C. 4 books✓
• D. 6 books

Explanation: Initially, Shelf A has 4 books and Shelf B has 8 books. To find how many books need to be removed from Shelf B so that both shelves have the same number of books, we can set up the equation: Let x be the number of books removed from Shelf B. After removal, Shelf A will have 4 books and Shelf B will have (8 - x) books. We want these two quantities to be equal: 4 = 8 - x Solving for x gives us: x = 8 - 4 = 4 Thus, 4 books must be removed from Shelf B for both shelves to have the same number of books (4 books each). The other options are incorrect because they do not result in equal numbers of books on both shelves.