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Sindh Mdcat Mock Paper 5 — Solved Past Paper with Answers
All 180 MCQs from Sindh Mdcat Mock Paper 5, solved with the correct answer highlighted and a full explanation for every question. This is a free MDCAT Sindh / DUHS past paper — no signup, no ads. Practise it interactively in timed mode, drill more with free MDCAT MCQs, or browse all Sindh / DUHS papers.
Attempt this paper interactively →Q1. Identify the word or phrase that needs to be changed for the sentence to be correct:
- A. Option A
- B. Option B✓
- C. Option C
- D. Option D
- E. Option E
Explanation: The send version of the verb is only used in the present tense in request form e.g Send me the email, send that version of the letter please etc. In the sentence past is being used so ‘sent’ will be used instead, so option B is the answer.
Why the other options are wrong
- A. "She" is a pronoun that refers to a female person. Using "she" in this sentence is gramatically correct
- C. The sender sent the speaker a "postal-order" as a form ofpayment or gift on their birthday. This doesn’t affect the sentence grammatically.
- D. As a noun, "birthday" serves as the object of thepreposition "on" and provides information about the timing or contextof the action described in the sentence.
- E. The sentence actually has an error as per stated in "Option A"
Q2. Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters. GLOOMY:
- A. Dark
- B. Bright✓
- C. Unexciting
- D. Faint
Explanation: "Gloomy" refers to a state or atmosphere that isdim, dark, or lacking in light. It often implies a feeling of sadness,melancholy, or a general lack of hope or optimism. Bright means giving out or reflecting much light; shining, so the total opposite. So option B is the answer as bright has the opposite meaning of gloomy.
Why the other options are wrong
- A. "Dark" shares a similar meaning with gloomy, as both refer to a lack of light or brightness.
- C. "Unexciting" suggests something dull, uninteresting, or lacking in excitement. While it may contribute to a negative mood, it does not specifically relate to the absence of light or brightness associated with gloomy.
- D. "Faint" refers to something weak, indistinct, or barely perceptible. It does not directly convey the opposite meaning of gloomy, which pertains more to the lighting or mood aspect.
Q3. Read the passage and answer the following question:“What a silly boy you are!” cried the miller. “I really don’t know what is the use of sending you to school. You seem not to learn anything. If little Hans came up here and saw our warm fire, our good supper, and our great cask of red wine, he might get envious. Envy is the most terrible thing and would spoil anybody’s nature. I certainly will not allow Hans’s nature to be spoiled. I am his best friend, and I will always watch over him, and see that he is not led into any temptations. Besides, if Hans came here, he might ask me to let him have some flour on credit, and that I could not do. Flour is one thing and friendship is another and they should not be confused. Why? The words are spelt differently and mean quite different things. Everybody can see that.” What does the statement “ Flour is one thing, and friendship is another” tell about the nature of miller?
- A. Very kind
- B. Selfish✓
- C. Friendly
- D. Caring
Explanation: If the miller was kind, he would have lent the flour.If the miller was friendly and caring, as he claims in the previous lines by saying “I will not allow Hans’s nature to be spoiled”, he would certainly let Hans have some flour on credit if he asked him for it.Since he is saying that he will not give flour on credit even to someone he cares for, this makes him selfish
Why the other options are wrong
- A. As per explanation, this is incorrect.
- C. As per explanation, this is incorrect.
- D. As per explanation, this is incorrect.
Q4. Complete the sentences by choosing the most appropriate option, from the given lettered choices. Two airplanes crashed _ the fog yesterday?
- A. On
- B. Of
- C. In✓
- D. To
Explanation: The correct preposition to complete the sentence is "in." Using "in" suggests that the crash happened within the foggy conditions, effectively describing the environment of the crash. "On" and "of" do not correctly convey this spatial relationship—"on" implies a surface, and "of" suggests possession. "To" indicates movement towards something, which is irrelevant to this context. Therefore, "in" is the most suitable choice.
Why the other options are wrong
- A. "On" is used to denote a surface or a position on a surface. Crashing "on" the fog implies an incorrect spatial relationship, as fog is not a tangible surface.
- B. "Of" typically indicates possession, origin, or association, which does not apply to describing the location of a crash in this context.
- D. "To" often indicates direction or movement towards a place, which does not fit the context of where the crash occurred.
Q5. Identify the word or phrase that needs to be changed for the sentence to be correct.It’s too late to go for a walk now; besides, it’s beginning to rain.
- A. It's
- B. Go
- C. Besides
- D. Beginning
- E. No Error✓
Explanation: The given sentence is an example of a compound sentence. A compound sentence contains at least two independent clauses. These two independent clauses can be connected with a comma and a coordinating conjunction or with a semicolon.
Why the other options are wrong
- A. “It’s” is a contraction and is used where a sentence would normally read “it is” or “it has”. The use of the word “it’s” in the given sentence makes sense grammatically and hence, does not need to be changed.
- B. The word “go” is acting as an action verb that is the base verb combined with the word “to” to make an infinitive verb. The infinitive (to go) is used to discuss an action (going for a walk) without actually doing the action. The use of the word “go” in the given sentence makes sense grammatically and hence, does not need to be changed.
- C. The word “besides” is a conjunctive adverb that is used here to connect two independent clauses. It is also used to add an extra fact (the extra fact here is that it had begun to rain) to an argument (the argument here is why it was too late to go for a walk then). The use of the word “besides” in the given sentence makes sense grammatically and hence, does not need to be changed.
- D. The word “beginning” is the present continuous tense of the word “begin” used to describe an event (rain) that is happening in the present. The use of the word “beginning” in the given sentence makes sense grammatically and hence, does not need to be changed.
Q6. Choose the word nearly opposite in meaning to the capitalized one. MUFFLED
- A. Loud✓
- B. Quiet
- C. Soft
- D. Noiseless
Explanation: The word 'muffled' describes a sound that is muted or not clear due to some form of obstruction. The correct opposite of 'muffled' is 'loud', which denotes a sound that is strong and easily heard.
Why the other options are wrong
- B. 'Quiet' means silent or making little noise, which can be similar to 'muffled' as both imply a reduction in sound.
- C. A 'soft' sound is gentle and not harsh, similar to 'muffled' since both suggest a less intense volume.
- D. 'Noiseless' implies complete silence, which can be akin to 'muffled', as both suggest a lack of strong sound.
Q7. Identify errors in the sentences:Because of their identical appearance and dress, the twins were often mistaken for each other.
- A. Because of
- B. Identical
- C. And dress
- D. Were
- E. No error✓
Explanation: There is no error in the sentence above according to grammar.
Why the other options are wrong
- A. Option A is wrong as "Because" word is correct in the sentence according to the rules of grammar.
- B. Option B is wrong as "identical" word does not need to be changed.
- C. Option C is wrong as "and dress" is correct in the context of the sentence.
- D. Option D is wrong as word "were" is correct in the context of the sentence according to the rules of grammar.
Q8. Complete the sentences by choosing the most appropriate option, from the given lettered choices below. We must _ back by six o’clock.
- A. Be✓
- B. Can
- C. Has
- D. Have
Explanation: The sentence requires a word that fits grammatically and logically in the expression 'must _ back by six o’clock.' The correct choice is 'be' because 'must be back' is a standard expression indicating an obligation or necessity to return by a specified time. The other options ('can,' 'has,' 'have') do not form correct or meaningful expressions in this context.
Why the other options are wrong
- B. 'Can' does not fit well because 'must can back' is not a grammatically correct or meaningful expression.
- C. 'Has' is incorrect because 'must has back' is not a grammatically correct phrase. The correct form would be 'must have,' but it doesn't fit in context here.
- D. 'Have' is incorrect in this context because 'must have back' does not form a proper expression to indicate a necessity to return.
Q9. Complete the sentences by choosing the most appropriate option, from the given lettered choices (A to D) below each. The recent discoveries of medical science have_ life and health to millions of people.
- A. Brought✓
- B. Bring
- C. Had bought
- D. Bringing
Explanation: The question is talking about a thing that has already happened, so bringing and bring would not be correct options. Option C changes the word to “bought” which has a totally different meaning so is incorrect. So option A is correct.
Why the other options are wrong
- B. "Bring" is the base form of the verb, but itdoesn't match the tense of the sentence. The sentence is in the present perfecttense, indicating actions that have occurred in the past with a connection tothe present.
- C. "Had brought" is the past perfect tense, whichimplies an action that happened before another past action. However, there isno need to convey a sequence of past events in this sentence, so the pastperfect tense is not necessary.
- D. "Bringing" is the present participle form of theverb "bring," which indicates an ongoing action. However, thesentence is talking about recent discoveries in the past that have already hadan impact on millions of people, so the present participle form is notsuitable.
Q10. Root pressure develops due to
- A. Passive absorption
- B. Active absorption✓
- C. Increase in transpiration
- D. Low osmotic potential in soil
Explanation: Root pressure develops due to active absorption of mineral ions by root cells. This lowers the water potential inside the roots, causing water to enter by osmosis. The inward movement of water generates a positive pressure called root pressure.
Why the other options are wrong
- A. Passive absorption involves water movement driven by transpiration and does not generate root pressure.
- C. Increased transpiration does not lead to root pressure; rather, it creates a negative pressure that helps in the upward movement of water through the plant.
- D. Low osmotic potential in soil would hinder water uptake, not contribute to root pressure.
Q11. Keratin is an example of:
- A. Transport protein
- B. Fibrous protein✓
- C. Catalytic protein
- D. Globular protein
Explanation: (b) Fibrous protein (Correct Answer) – Keratin is a fibrous structural protein that provides strength and protection in hair, nails, and skin.
Why the other options are wrong
- A. (a) Transport protein – Incorrect. Transport proteins help move substances across cell membranes, like hemoglobin or ion channels.
- C. c) Catalytic protein – Incorrect. Catalytic proteins are enzymes that speed up chemical reactions, such as amylase and pepsin.
- D. (d) Globular protein – Incorrect. Globular proteins have a rounded shape and are usually soluble in water (e.g., enzymes, antibodies, hemoglobin). Keratin, being fibrous, does not fall in this category.
Q12. It is an example of keto-pentose:
- A. Ribulose✓
- B. Fructose
- C. Ribose
- D. Sedoheptulose
Explanation: (a) Ribulose (Correct Answer) – Ribulose is a five-carbon sugar (pentose) with a ketone functional group, making it a keto-pentose.
Why the other options are wrong
- B. (b) Fructose – Incorrect. Fructose is a keto-hexose because it has six carbons and a ketone group.
- C. (c) Ribose – Incorrect. Ribose is an aldo-pentose, meaning it has an aldehyde group, not a ketone.
- D. (d) Sedoheptulose – Incorrect. Sedoheptulose is a keto-heptose because it has seven carbons and a ketone group.
Q13. Which part of the tobacco plant is infected by Meloidogyne incognita?
- A. Stem
- B. Root✓
- C. Flower
- D. Leaf
Explanation: Meloidogyne incognita, commonly referred to as the root-knot nematode, infects the roots of the tobacco plant. The nematode is so named because it causes the formation of galls or knots on the roots, disrupting the plant's ability to absorb water and nutrients efficiently. This results in stunted growth and can significantly diminish crop yield. While the stem, leaves, and flowers may show signs of stress due to root damage, they are not directly infected by the nematode. Thus, the root is the primary site of infection.
Why the other options are wrong
- A. Although issues with the stem can arise due to poor root health, Meloidogyne incognita primarily targets the roots, not the stems directly.
- C. Flowers are not typically affected by root-knot nematodes like Meloidogyne incognita, as their primary site of infection is the root system.
- D. Leaves are not the primary target of Meloidogyne incognita. This nematode specifically infects the roots, leading to systemic issues that indirectly affect the leaves.
Q14. The deficiency of which of the following causes severe combined immunodeficiency?
- A. Hypoxanthine-guanine transferase
- B. Xanthine oxidase
- C. PRPP synthetase
- D. Adenosine deaminase✓
Explanation: ADA deficiency leads to SCID, a group of rare, inherited disorders characterized by a severe impairment of both the T and B lymphocytes of the immune system. Adenosine deaminase is involved in the breakdown of purines, and its deficiency results in the accumulation of toxic metabolites. that are particularly harmful to developing immune cells.
Why the other options are wrong
- A. Deficiency in hypoxanthine-guanine phosphoribosyltransferase (HGPRT) leads to Lesch-Nyhan syndrome, which is primarily characterized by neurological and behavioral abnormalities, along with an overproduction of uric acid. However, it is not linked to severe combined immunodeficiency (SCID).
- B. Xanthine oxidase is an enzyme critical for purine metabolism, facilitating the breakdown of purines into uric acid. Deficiency in this enzyme results in xanthinuria, marked by elevated levels of xanthine in the urine, but does not cause SCID.
- C. PRPP synthetase plays a key role in synthesizing 5-phosphoribosyl-1-pyrophosphate (PRPP), which is vital for nucleotide synthesis. A deficiency here can lead to PRPP synthetase superactivity, resulting in excessive purine production, but it is not associated with SCID.
Q15. Which one of the following technique rapidly replicates specific target fragment of DNA without cloning?
- A. DNA sequencing
- B. Genetic probe
- C. Gel electrophoresis
- D. Polymerase chain reaction✓
Explanation: PCR involves using short synthetic DNA fragments called primers to select a segment of the genome to be amplified, and then multiple rounds of DNA synthesis to amplify that segment.
Why the other options are wrong
- A. DNA sequencing refers to the general laboratory technique for determining the exact sequence of nucleotides, or bases, in a DNA molecule.
- B. A gene probe (also known as DNA probe or nucleic acid probe) is a single-stranded DNA or RNA fragment of known structure or function and is used to detect a target sequence of DNA in a sample
- C. Gel electrophoresis is a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size.
Q16. Nucleotides sequence that is identical to its complementary strand when each is read in the same chemical direction for example i-e; 5'GATC3' 3'CATG5' these are called as:
- A. Flanking sequences
- B. Nucleotide order
- C. Palindromic sequences✓
- D. Antagonistic sequences
Explanation: Palindromic sequences occur when a sequence of base pairs reads the same in both directions on complementary strands, like 5' GATC 3' and 3' CTAG 5'. Such sequences play a crucial role in genetic engineering, particularly in restriction enzyme recognition and cutting of DNA. The other options do not fit this definition: Flanking sequences are adjacent to DNA regions of interest, Nucleotide order refers to the sequence without implying symmetry, and Antagonistic sequences is not a concept in DNA sequence terminology.
Why the other options are wrong
- A. Flanking sequences are the regions adjacent to a specific DNA sequence, not characterized by identical reading in both directions.
- B. Nucleotide order simply refers to the linear sequence of nucleotides in a strand of DNA, without the reversible characteristic.
- D. Antagonistic sequences is not a recognized term in genetics with respect to DNA sequences.
Q17. In case of cystic fibrosis, the solution containing gene coated liposomes is sprayed into patients:
- A. Oral cavity
- B. Nostrils✓
- C. Thoracic cavity
- D. Mouth
Explanation: For treatment of cystic fibrosis, a solution containing gene coated liposomes is sprayed into patient's nostrils.
Why the other options are wrong
- A. Administering gene therapy through the oral cavity is ineffective for cystic fibrosis. The oral route does not deliver the gene to the respiratory epithelial cells, which are essential for treating the condition. Therefore, this option is incorrect.
- C. The thoracic cavity is not a viable route for delivering gene therapy. This option suggests a surgical approach, which is invasive and unsafe. Gene therapy for cystic fibrosis is designed to be administered non-invasively through the nasal passages, making this option incorrect.
- D. Similar to the oral cavity, administering the gene therapy through the mouth does not effectively reach the respiratory epithelial cells. The therapy needs to be targeted through the nasal passages for optimal delivery, making this option incorrect.
Q18. In vivo method of treatment is being tried in:
- A. SCIDS
- B. Cystic fibrosis✓
- C. Hypercholesterolemia
- D. Familial hypercholesterolemia
Explanation: The gene is introduced into the nasal sinus by coating it on liposomes which are sprayed just like inhalers in the nasal sinuses.
Why the other options are wrong
- A. SCIDS (Severe Combined Immunodeficiency Syndrome) is usually treated with ex vivo gene therapy. In this method, bone marrow stem cells are taken out of the patient’s body, infected with a retrovirus carrying the normal gene, and then reintroduced into the patient. Since the correction takes place outside the body (ex vivo), this option is not correct for in vivo treatment.
- C. Hypercholesterolemia, particularly familial hypercholesterolemia, involves defective LDL receptors. In gene therapy approaches, ex vivo techniques are often tried, where liver cells are modified outside the body and then returned. So, it does not primarily involve in vivo trials. This makes it an incorrect option here.
- D. Familial hypercholesterolemia is a severe inherited form of high cholesterol caused by mutations in the LDL receptor gene. While gene therapy has been explored for this condition, most of the approaches have focused on ex vivo methods, where liver cells are genetically altered in laboratory conditions and then transplanted back into the patient. It is not the standard example of in vivo treatment under study, so this option is also incorrect.
Q19. Liver cells are infected with retrovirus containing normal gene for the receptor for the treatment of:
- A. SCIDS
- B. Cystic fibrosis
- C. Hypercholesterolemia✓
- D. Cardiovascular disorder
Explanation: In this gene therapy, liver cells are infected with a retrovirus carrying the normal LDL receptor gene. This helps remove excess LDL cholesterol from the blood
Why the other options are wrong
- A. Severe Combined Immunodeficiency Syndrome (SCIDS) is a genetic disorder that affects the immune system. It is not treated by targeting liver cells or using retroviruses for gene delivery in the context described.
- B. Cystic fibrosis is a genetic disorder that primarily affects the lungs and digestive system. The treatment typically involves therapies targeting the lungs rather than liver cells.
- D. Cardiovascular disorders encompass a range of conditions affecting the heart and blood vessels. While cholesterol levels can impact cardiovascular health, the specific treatment detailed in the question pertains to hypercholesterolemia, not general cardiovascular disorders.
Q20. For the treatment of SCIDS, bone marrow stem cells are removed from the blood and are infected with a:
- A. Bacteriophage
- B. Retrovirus✓
- C. Lambda virus
- D. Bacterium
Explanation: The retrovirus acts as a vector for gene therapy.
Why the other options are wrong
- A. Bacteriophages are viruses that infect bacteria and are not used in gene therapy for SCIDS. They specifically target bacterial cells, not human cells.
- C. Lambda viruses primarily infect bacteria, particularly Escherichia coli, and are not appropriate for use in human gene therapy applications.
- D. Bacteria are living organisms and cannot serve as vectors for gene therapy. They do not deliver genetic material to human cells in the context of gene therapy.
Q21. There are two main methods used for gene therapy i.e:
- A. Ex – vivo and in vivo✓
- B. Ex vivo – Ex vitro
- C. Ex – vivo and in vitro
- D. In vitro – Ex vitro
Explanation: In ex-vivo method cells or tissurs are taken out of the body and after insersion of normal genes they are implanted in the body. However, in in-vivo method gene/genes is/are inserted into the cells or at their original site in the body.
Why the other options are wrong
- B. Ex vivo refers to procedures performed on living tissue outside of the organism, while Ex vitro typically involves experiments conducted outside of living organisms, such as in soil or other non-biological media. This option does not accurately represent the methods of gene therapy.
- C. Ex vivo involves working with cells or tissues removed from a living organism, while in vitro means experiments are performed outside of a living organism. Neither of these accurately describes the processes used in gene therapy methods.
- D. In vitro refers to studies conducted outside of a living organism, typically in a lab setting, and Ex vitro describes environments outside of artificial tissue culture. This option does not correctly identify either method of gene therapy.
Q22. A decrease in blood pressure/volume will not cause the release of:
- A. Atrial natriuretic factor✓
- B. Aldosterone
- C. ADH
- D. Renin
Explanation: The correct answer is Atrial natriuretic factor (ANF). ANF is secreted by the atria of the heart in response to increased blood volume and pressure, not a decrease. It works to reduce blood volume and pressure by promoting sodium excretion and decreasing the release of aldosterone. On the other hand, Aldosterone, ADH, and Renin are all released in response to a decrease in blood pressure or volume. Aldosterone increases sodium reabsorption, ADH reduces water excretion, and renin triggers the renin-angiotensin-aldosterone system to increase blood pressure.
Why the other options are wrong
- B. Aldosterone is released to counteract low blood pressure or volume by increasing sodium reabsorption, which leads to water retention, thus increasing blood volume and pressure.
- C. Antidiuretic hormone (ADH) helps to conserve water in the body in response to low blood pressure or volume, thereby increasing blood volume and pressure.
- D. Renin is released in response to low blood pressure, activating a series of reactions that lead to an increase in blood pressure.
Q23. The part of the nephron involved in active reabsorption of sodium is:
- A. Distal convoluted tubule
- B. Ascending loop of Henle✓
- C. Bowman’s capsule
- D. Descending limb of Henle’s loop
Explanation: The correct answer is the ascending loop of Henle, which is crucial for the active reabsorption of sodium ions from the filtrate back into the bloodstream. This segment utilizes active transport mechanisms to move sodium ions against their concentration gradient, which is essential for maintaining osmotic balance and blood pressure.The distal convoluted tubule causes gradual osmotic outlow of water from the iltrate back to kidney as it passes downward in the descending loop of Henle. Bowman's capsule serves a different function by filtering blood but does not participate in sodium reabsorption. Finally, the descending limb of Henle's loop is primarily involved in the passive reabsorption of water, making it ineffective for sodium reabsorption.
Why the other options are wrong
- A. The distal convoluted tubule (DCT) causes gradual osmotic outlow of water from the iltrate back to kidney as it passes downward in the descending loop of Henle.
- C. Bowman's capsule is responsible for the filtration of blood to produce filtrate but does not play a role in the reabsorption of sodium or other substances.
- D. The descending limb of Henle’s loop primarily facilitates water reabsorption due to its permeable nature but does not engage in active sodium reabsorption.
Q24. Which of the following does NOT favour the formation of large quantities of dilute urine?
- A. Renin✓
- B. Atrial Natriuretic Factor (ANF)
- C. Alcohol
- D. Caffeine
Explanation: Renin promotes sodium/water retention, reducing dilute urine formation.
Why the other options are wrong
- B. Atrial Natriuretic Factor (ANF) promotes the excretion of sodium and water, which leads to increased urine production and dilution.
- C. Alcohol acts as a diuretic by inhibiting the release of antidiuretic hormone (ADH), resulting in increased urine output and dilution.
- D. Caffeine is a diuretic that blocks the action of ADH, increasing urine volume and leading to the production of dilute urine.
Q25. The maximum amount of electrolytes and water (70 – 80 %) from the glomerular filtrate is reabsorbed in which part of the nephron?
- A. Ascending limb of loop of Henle
- B. Distal convoluted tubule
- C. Proximal convoluted tubule✓
- D. Descending limb of loop of Henle
Explanation: During glomerular filtration in kidneys, ultrafiltration of blood occurs i.e: almost all the constituents of plasma except proteins pass onto the Bowman’s capsule.Then nearly 99% of the filtrate is reabsorbed by renal tubules.The proximal convoluted tubules show maximum reabsorption and nearly all the essential nutrients and 70-80% of electrolytes and water are reabsorbed by this segment.
Why the other options are wrong
- A. The ascending limb of Henle's loop primarily reabsorbs sodium chloride (NaCl) and is impermeable to water, contributing to the creation of a concentration gradient in the medulla. It is not the site for maximum reabsorption of water and electrolytes.
- B. The distal convoluted tubule (DCT) plays a role in the fine-tuning of electrolyte and fluid balance, but it is not the primary site for massive reabsorption of water and electrolytes from the filtrate.
- D. The descending limb of the loop of Henle is primarily involved in the reabsorption of water, which concentrates the filtrate. However, it is not the nephron segment responsible for the maximum reabsorption of both electrolytes and water.
Q26. A fall in glomerular filtration rate (GFR) activates:
- A. Juxtaglomerular cells to release renin✓
- B. Adrenal cortex to release aldosterone
- C. Adrenal medulla to release adrenaline
- D. Posterior pituitary to release vasopressin
Explanation: Low GFR triggers renin release to maintain blood pressure.
Why the other options are wrong
- B. The release of aldosterone from the adrenal glands is regulated via the renin-angiotensin II-aldosterone system. This system is initially activated via a decrease in the mean arterial blood pressure to increase the blood pressure.
- C. Adrenaline is produced in the adrenal glands, which release adrenaline into the body during times of stress or danger. It prepares your body to face a stressful “fight or flight” situation.
- D. Vasopressin release is regulated by osmoreceptors in the hypothalamus, which are exquisitely sensitive to changes in plasma osmolality. Under hyperosmolar conditions, osmoreceptor stimulationleads to vasopressin release and stimulation of thirst. These two mechanisms result in increased water intake and retention.
Q27. Which one of the following is not a part of a renal pyramid?
- A. Peritubular capillaries
- B. Convoluted tubules✓
- C. Collecting ducts
- D. Loop of Henle
Explanation: Convoluted tubules are in renal cortex, not in pyramids.
Why the other options are wrong
- A. Peritubular capillaries surround the nephron tubules in the cortex and are involved in the reabsorption and secretion processes, not part of the renal pyramid.
- C. Collecting ducts are located in the renal pyramids, where they transport urine to the renal pelvis.
- D. The Loop of Henle descends into the medullary pyramids, playing a key role in the concentration of urine.
Q28. Which one of the following statements is correct with respect to kidney function regulation?
- A. When someone drinks a large amount of water, ADH release is suppressed.✓
- B. Exposure to cold temperatures stimulates ADH release.
- C. An increase in glomerular blood flow stimulates formation of angiotensin II.
- D. During summer when the body loses a lot of water due to evaporation, the release of ADH is suppressed.
Explanation: Antidiuretic hormone (ADH) or vasopressin increases the reabsorption of water in the distal convoluted tubule, collecting tubules and collecting ducts of the nephrons of the kidneys. As a result, the reabsorption of water from the glomerular filtrate is increased. When someone drinks lot of water, requirement of absorption of water decreases, so ADH release is suppressed.
Why the other options are wrong
- B. Cold temperatures do not directly stimulate ADH release; ADH is primarily regulated by fluid balance and osmolarity.
- C. An increase in glomerular blood flow typically results in higher filtration rates but does not directly stimulate angiotensin II formation.
- D. In conditions of water loss, such as during summer, ADH release is actually increased to conserve water.
Q29. Uricotelic mode of excreting nitrogenous wastes is found in:
- A. Reptiles and birds✓
- B. Birds and annelids
- C. Amphibians and reptiles
- D. Insects and amphibians
Explanation: The correct answer is Reptiles and birds. These animals are uricotelic, meaning they excrete nitrogenous wastes as uric acid, which is advantageous in conserving water due to its low solubility. This adaptation is particularly beneficial for survival in arid and water-scarce environments. On the other hand, while insects also excrete uric acid, amphibians usually excrete urea or ammonia, reflecting their more aquatic lifestyles. Annelids excrete ammonia or urea, not uric acid, which is why options involving these animals are incorrect.
Why the other options are wrong
- B. While birds are uricotelic, annelids typically excrete ammonia or urea, not uric acid.
- C. Amphibians primarily excrete urea or ammonia, especially in aquatic environments, whereas reptiles are uricotelic.
- D. Insects are uricotelic, excreting uric acid to conserve water, but amphibians are not, as they often excrete urea or ammonia.
Q30. A person who is on a long hunger strike and is surviving only on water, will have:
- A. Less amino acids in his urine
- B. More glucose in his blood
- C. Less urea in his urine✓
- D. More sodium in his urine.
Explanation: During starvation, the body must rely on body proteins for the amino acids. On high protein diets the carbon skeletons of the amino acids are oxidized for energy or stored as fat and glycogen, but the amino nitrogen must be excreted. To facilitate this process, enzymes of the urea cycle are controlled at the gene level. When dietary proteins increase significantly, enzyme concentrations rise. On return to a balanced diet, enzyme levels decline. Under conditions of starvation, enzyme levels rise as proteins are degraded and amino acid carbon skeletons are used to provide energy, thus increasing the quantity of nitrogen that must be excreted in the form of urea.
Why the other options are wrong
- A. This is incorrect because starvation leads to the breakdown of body proteins, increasing amino acid breakdown products in the urine.
- B. This is incorrect because during prolonged fasting, blood glucose levels tend to decrease as glycogen stores are depleted to provide for the decreasing energy levels.
- D. This is incorrect because sodium levels are typically conserved during fasting to maintain electrolyte balance.
Q31. If the loop of Henle were absent from the mammalian nephron, which one of the following is to be expected?
- A. There will be no urine formation.
- B. There will be hardly any change in the quality and quantity of urine formed
- C. The urine will be more concentrated
- D. The urine will be more dilute✓
Explanation: Reabsorption is a process by which useful constituents of the glomerular filtrate are returned into the bloodstream. It occurs in convoluted tubules (proximal convoluted tubule) as well as the loop of Henle. Basically loop of Henle, in association with the vasa recta, plays an important role in the countercurrent mechanism (the process which makes urine hypertonic, i.e., more concentrated). Therefore, if Henle’s loop was absent from the mammalian nephron, the urine would be more dilute.
Why the other options are wrong
- A. Henle's loop and vasa recta play an important role in the concentration of urine. When the filtrate flows in the two limbs o Henle's loop, the flow is in opposite directions, i.e.counter-current. Similarly, blood flows through the two limbs of the vasa recta in a countercurrent pattern.
- B. Quality and quantity of the urine will be affected as the loop of Henle is responsible for reabsorption of water and ions.
- C. No urine will not be concentrated because loop of henle plays a role in concentration of urine.
Q32. A condition of failure of kidney to form urine is called:
- A. Anuria✓
- B. Deamination
- C. Uremia
- D. Oliguria
Explanation: Anuria is the medical term for the complete cessation of urine production by the kidneys, often resulting from severe kidney damage or failure. In contrast, 'Deamination' refers to a metabolic process unrelated to kidney function. 'Uremia' describes a condition where waste products accumulate in the blood due to impaired kidney function, but does not specifically indicate the absence of urine production. Therefore, Anuria is the correct choice as it directly addresses the failure to form urine.
Why the other options are wrong
- B. Deamination is a process in protein metabolism where amino groups are removed, which is unrelated to urine formation.
- C. Uremia is a condition where waste products like urea accumulate in the blood due to kidney dysfunction, but it does not specifically mean urine is not produced.
- D. Oliguria refers to a reduced urine output, not a complete cessation, thus it does not describe the total failure to produce urine as 'Anuria' does.
Q33. In sexual reproduction, sex cells contain _ chromosomes when compared to other cells of the body:
- A. Same
- B. Half✓
- C. Double
- D. All of the above
Explanation: In sexual reproduction, sex cells (gametes) are formed through a process called meiosis, which reduces the chromosome number by half. This is crucial because it ensures that when two gametes fuse during fertilization, the resulting offspring has the correct diploid number of chromosomes. Option B is correct because sex cells contain half the number of chromosomes compared to somatic cells. Option A is incorrect because gametes do not have the same number of chromosomes as body cells. Option C is incorrect because gametes do not contain double the chromosomes. Option D is incorrect as only one option accurately describes the chromosome number in sex cells.
Why the other options are wrong
- A. This option is incorrect. Sex cells, or gametes, do not contain the same number of chromosomes as somatic cells. They undergo meiosis, which reduces the chromosome number.
- C. This option is incorrect. Sex cells do not have double the number of chromosomes; instead, they have half to ensure genetic diversity and stability in the offspring.
- D. This option is incorrect. Only one of the provided statements is true for sex cells concerning their chromosome number compared to other body cells.
Q34. Pituitary gland releases _ hormone and _ hormone while ovaries produce _ and progesterone.
- A. Follicle-stimulating and luteinizing, estrogen✓
- B. Estrogen and follicle-stimulating, luteinizing
- C. Luteinizing and estrogen, follicle-stimulating
- D. Follicle-stimulating and estrogen, luteinizing
Explanation: The pituitary gland is responsible for releasing the follicle-stimulating hormone (FSH) and luteinizing hormone (LH), both of which play key roles in regulating the reproductive processes. The ovaries, on the other hand, produce estrogen and progesterone, which are crucial for the development and regulation of the female reproductive system. Options B, C, and D incorrectly assign estrogen to the pituitary gland or misplace the order of the hormones.
Why the other options are wrong
- B. Incorrect. Estrogen is produced by the ovaries, not the pituitary gland. The correct hormones produced by the pituitary gland are FSH and LH.
- C. Incorrect. While LH is produced by the pituitary gland, estrogen is produced by the ovaries. FSH is another hormone produced by the pituitary gland, not by the ovaries.
- D. Incorrect. Estrogen is not produced by the pituitary gland. The pituitary gland releases FSH and LH, whereas the ovaries produce estrogen.
Q35. Which one is NOT an involuntary function:
- A. Breathing
- B. Pumping of blood
- C. Skeletal muscle movement✓
- D. Blinking of eyes
Explanation: Involuntary functions are those that occur without our conscious control.Skeletal muscle movement is not an involuntary function;it is voluntary/intentional.Blinking of eyes, heart-pumping of blood, and breathing are all involuntary.
Why the other options are wrong
- A. According to the given explanation, this is not correct.
- B. According to the given explanation, this is not correct.
- D. According to the given explanation, this is not correct.
Q36. The passageways of the respiratory system have mucous secreting cells called:
- A. Tracheal cells
- B. Goblet cells✓
- C. Surfactant cells
- D. Pleural cells
Explanation: Goblet cells are the specialized cells within the respiratory tract responsible for secreting mucus, which helps trap dust and microbes.
Why the other options are wrong
- A. While tracheal cells include goblet cells, they also contain ciliated cells which are not responsible for secreting mucus. Therefore, tracheal cells as a whole are not specifically mucous-secreting.
- C. Surfactant cells, or type II alveolar cells, produce surfactant to reduce surface tension in the alveoli, not mucus in the passageways.
- D. Pleural cells line the pleural cavity, involved in protecting the lungs, but are not related to mucus secretion in the respiratory passageways.
Q37. A man who has type AB blood cannot father a child with type _ blood, because he would pass on either the _ or the B allele to all of his offspring.
- A. A,O
- B. O,A✓
- C. B, O
- D. B, A
Explanation: The father can pass on either the A or B allele to each of his offspring. Even if the mother has blood type O, the child cannot have blood type O because of the A or B allele received from the father. A and B alleles are dominant over O. For blood type O (the recessive phenotype) to occur, there should be two copies of the O allele, one from each parent. This is impossible in the given situation.
Why the other options are wrong
- A. a) A, O – IncorrectThe statement says the man cannot father a child with type A or type O.But this is wrong because he can have a child with type A if the other parent contributes an "A" or "O" allele (e.g., if the mother is type A or O).However, he cannot have a child with type O, so the "O" part is correct, but "A" makes this option incorrect
- C. c) B, O – IncorrectThe statement suggests he cannot have a child with type B or O.But he can have a child with type B if the mother contributes a B or O allele.Again, he cannot have a child with type O, but including B in the option makes it incorrect.
- D. d) B, A – IncorrectThis statement says he cannot have a child with type B or type A, but this is wrong because he can have children with both A and B blood types, depending on the other parent's alleles.Since both A and B are possible, this option is incorrect.
Q38. Identify purine and pyrimidines from the following figures
- A. a and b purines, c, d, and e pyrimidines
- B. d and b purines, c, a and e pyrimidines
- C. a and e purines, c, d, and b pyrimidines
- D. a and c purines b, d, and e pyrimidines.✓
Explanation: Purines are those bases that are double-ringed. Pyrimidines have a single ring. As we can see, a and c are double-ringed so they are purines. b,c and d are single rings so they are pyrimidines.
Why the other options are wrong
- A. As per explanation, this is incorrect.
- B. As per explanation, this is incorrect.
- C. As per explanation, this is incorrect.
Q39. A cross between a black cat and a tan cat produces a tabby pattern (black and tan fur together). What percent of kittens would have tan fur if a tabby cat is crossed with a black cat?
- A. 100%
- B. 50%
- C. 25%
- D. 0%✓
Explanation: The correct answer is 0%. The black cat is homozygous for the black fur gene (BB) and does not carry an allele for tan fur. The tabby cat, being a hybrid, has one black fur allele (B) and one tan fur allele (T). When crossed with a black cat, the potential offspring genotypes are BB (black) and BT (tabby), with no possibility of a TT (tan) genotype. Thus, none of the kittens will have tan fur. The other options are incorrect because they suggest the presence of a tan allele in the black parent, which is not possible given the genetic information provided.
Why the other options are wrong
- A. If all offspring were tan, it would mean both parents carry only the tan gene, which is not the case here. The cross involves a tabby cat (BT) and a black cat (BB), which cannot produce tan-only offspring.
- B. For 50% of the offspring to be tan, the tabby cat would need to pass the tan gene (T) to half of its offspring, but the black cat (BB) has no tan gene to contribute.
- C. For 25% of the offspring to be tan, there must be a recessive tan gene present in both parents, but the black cat (BB) does not carry a tan allele.
Q40. Haemophilia is a sex-linked _ trait.
- A. Dominant
- B. Co-dominant
- C. Pleiotropic
- D. Recessive✓
Explanation: Haemophilia is a sex-linked recessive disorder. The abnormal gene responsible for haemophilia is carried on the X chromosome. Recessiveness is proved by the fact that when a woman has this gene on one X and a normal gene on the other X (heterozygous for hemophilia), she does not show haemophilia in phenotype.
Why the other options are wrong
- A. a) Dominant – Incorrect because haemophilia is not a dominant trait; affected males only need one faulty X chromosome, but females need two.
- B. b) Co-dominant – Incorrect because there is no equal expression of both normal and mutant alleles.
- C. c) Pleiotropic – Incorrect because pleiotropy refers to one gene affecting multiple traits, while haemophilia specifically affects blood clotting.
Q41. The "d" and "D" alleles are used for lighter and darker skin colour in humans, respectively. By keeping in view the inheritance pattern of skin colour in human beings(controlled by 3 genes), choose which combination shows medium skin colour from the following picture:
- A. Column A
- B. Column C✓
- C. Column D
- D. Column E
Explanation: The correct answer is Column C because it presents a balanced number of dominant (D) and recessive (d) alleles across all three genes, which results in a medium skin color. In contrast, Column A is incorrect as it shows homozygous recessive alleles (ddd) for all genes, leading to the lightest possible skin color. Column D is incorrect because it fails to show a balance between dominant and recessive alleles, skewing towards either lighter or darker skin. Column E is incorrect as it does not reflect the polygenic nature of skin color inheritance, which involves multiple genes working together, not just a single gene or row.
Why the other options are wrong
- A. This option is incorrect because it displays homozygous recessive genotypes (ddd) for all three genes, leading to the lightest possible skin color.
- C. This option is incorrect because it showcases a predominance of either dominant or recessive alleles, which does not result in a medium skin color.
- D. This option is incorrect as it does not adequately represent the polygenic nature of skin color determination, which requires a combination of multiple genes rather than a focus on a single row.
Q42. A/An _ is mostly a non-protein chemical compound that is required for the protein’s biological activity.
- A. Active site
- B. Substrate
- C. Cofactor✓
- D. Enzyme
Explanation: The correct answer is 'Cofactor'. A cofactor is a non-protein chemical compound required for the biological activity of some proteins, particularly enzymes. Cofactors can be metal ions or organic molecules and are essential for the catalytic activity of many enzymes.The other options are incorrect because:'Active site' refers to the region of the enzyme where the substrate binds, not a separate chemical compound.'Substrate' is the molecule upon which the enzyme acts, not a non-protein compound required for enzyme activity.'Enzyme' itself is a protein that facilitates biochemical reactions, whereas a cofactor is a non-protein component needed for some enzyme activities.
Why the other options are wrong
- A. The active site is the part of an enzyme where the substrate binds and the reaction is catalyzed. It is not a separate chemical compound but a specific region of the enzyme.
- B. The substrate is the specific reactant that an enzyme acts upon during a biochemical reaction. It is not a non-protein chemical compound required for the enzyme's activity.
- D. Enzymes are proteins that catalyze biochemical reactions, often requiring cofactors to function properly. They are not non-protein compounds themselves.
Q43. A group of biologically active molecules formed from amino acids which interact with the surface of the lipid bilayer of cell membranes are called:
- A. Integral Proteins
- B. Peripheral proteins✓
- C. Cell wall
- D. Plasmodesmata
Explanation: Peripheral proteins, or peripheral membrane proteins, are a group of biologically active molecules formed from amino acids which interact with the surface of the lipid bilayer of cell membranes. Unlike integral membrane proteins, peripheral proteins do not enter into the hydrophobic space within the cell membrane. Instead, peripheral proteins have specific sequences of amino acids which allow them to attract to the phosphate heads of the lipid molecules or to integral proteins.
Why the other options are wrong
- A. Integral proteins are proteins that are permanently embedded in a cell's membrane. They are essential for life and perform many functions, including transporting molecules, generating energy, and transducing signals.
- C. A cell wall is a rigid or flexible layer that surrounds some cells, providing structure, protection, and shape. Cell walls are found in bacteria, fungi, algae, and plants.
- D. Plasmodesmata are microscopic channels that connect plant and some algal cells. They allow for communication and transport between cells.
Q44. Read the passage below to answer the question:Hemophilia is a disorder in which blood fails to clot. Saad, a male hemophiliac, marries Sara, a normal woman and together they have four children, two boys (Ahmed and Ali) and two girls (Alia and Ayesha). None of the children display the symptoms of Hemophilia. Ahmed, Ali, Ayesha, and Ali all marry normal individuals and have children. None of Ahmeds or Ali’s children, male or female, display symptoms of hemophilia, but the sons of Alia and Ayesha display symptoms of hemophilia while the daughters of Alia and Ayesha do not. Which of the following individuals are heterozygous for hemophilia:
- A. Saad, Ahmed, and Ali
- B. Ahmed, Ali, Alia, and Ayesha
- C. Saad and Sara
- D. Alia and Ayesha✓
- E. Ahmed and Ali
Explanation: Hemophilia is an X-linked recessive disorder, meaning that males (XY) need only one affected X chromosome to express the disorder, while females (XX) need two affected X chromosomes to have the disease.Saad (hemophiliac male) has only one X chromosome, which carries the hemophilia mutation, and a Y chromosome.Sara (normal female) has two normal X chromosomes.Ahmed and Ali (sons of Saad and Sara) inherit their Y chromosome from Saad and a normal X chromosome from Sara, so they are unaffected.Alia and Ayesha (daughters of Saad and Sara) inherit one affected X chromosome from Saad and one normal X chromosome from Sara, making them carriers (heterozygous) for hemophilia.Since Alia and Ayesha are carriers, they do not show symptoms themselves but can pass the affected X chromosome to their sons. Their sons receive their Y chromosome from their fathers and have a 50% chance of inheriting the affected X chromosome from their mothers, leading to hemophilia.Thus, Alia and Ayesha are heterozygous for hemophilia.
Why the other options are wrong
- A. This is not correct as per explanations.
- B. Hemophilia is an X-linked recessive disorder, meaning that males (XY) need only one affected X chromosome to express the disorder, while females (XX) need two affected X chromosomes to have the disease.Saad (hemophiliac male) has only one X chromosome, which carries the hemophilia mutation, and a Y chromosome.Sara (normal female) has two normal X chromosomes.Ahmed and Ali (sons of Saad and Sara) inherit their Y chromosome from Saad and a normal X chromosome from Sara, so they are unaffected.Alia and Ayesha (daughters of Saad and Sara) inherit one affected X chromosome from Saad and one normal X chromosome from Sara, making them carriers (heterozygous) for hemophilia.Since Alia and Ayesha are carriers, they do not show symptoms themselves but can pass the affected X chromosome to their sons. Their sons receive their Y chromosome from their fathers and have a 50% chance of inheriting the affected X chromosome from their mothers, leading to hemophilia.Thus, Alia and Ayesha are heterozygous for hemophilia.
- C. Saad (hemophiliac male) has only one X chromosome, which carries the hemophilia mutation, and a Y chromosome.Sara (normal female) has two normal X chromosomes.
- E. Hemophilia is an X-linked recessive disorder, meaning that males (XY) need only one affected X chromosome to express the disorder, while females (XX) need two affected X chromosomes to have the disease.Saad (hemophiliac male) has only one X chromosome, which carries the hemophilia mutation, and a Y chromosome.Sara (normal female) has two normal X chromosomes.Ahmed and Ali (sons of Saad and Sara) inherit their Y chromosome from Saad and a normal X chromosome from Sara, so they are unaffected.Alia and Ayesha (daughters of Saad and Sara) inherit one affected X chromosome from Saad and one normal X chromosome from Sara, making them carriers (heterozygous) for hemophilia.Since Alia and Ayesha are carriers, they do not show symptoms themselves but can pass the affected X chromosome to their sons. Their sons receive their Y chromosome from their fathers and have a 50% chance of inheriting the affected X chromosome from their mothers, leading to hemophilia.Thus, Alia and Ayesha are heterozygous for hemophilia.
Q45. Given below is the ECG of a normal human. Which one of its components is correctly interpreted below?
- A. Complex QRS - one complete pulse
- B. Peak T initiation of total cardiac contraction
- C. Peak P and peak R together systolic and diastolic blood pressures
- D. Peak P initiation of left atrial contraction only✓
Explanation: P wave represents atrial depolarization, which initiates contraction of the atria.QRS complex represents ventricular depolarization, not “one complete pulse.”T wave represents ventricular repolarization, not initiation of total cardiac contraction.Blood pressures are not directly represented by peaks on the ECG.
Why the other options are wrong
- A. P wave represents atrial depolarization, which initiates contraction of the atria.QRS complex represents ventricular depolarization, not “one complete pulse.”T wave represents ventricular repolarization, not initiation of total cardiac contraction.Blood pressures are not directly represented by peaks on the ECG.
- B. P wave represents atrial depolarization, which initiates contraction of the atria.QRS complex represents ventricular depolarization, not “one complete pulse.”T wave represents ventricular repolarization, not initiation of total cardiac contraction.Blood pressures are not directly represented by peaks on the ECG.
- C. P wave represents atrial depolarization, which initiates contraction of the atria.QRS complex represents ventricular depolarization, not “one complete pulse.”T wave represents ventricular repolarization, not initiation of total cardiac contraction.Blood pressures are not directly represented by peaks on the ECG.
Q46. If due to some injury, the chordae tendinae of the tricuspid valve of the human heart is partially non-functional. What will be the immediate effect?
- A. The flow of blood into the aorta will be slowed down
- B. The 'pacemaker' will stop working
- C. The blood will tend to flow back into the left atrium
- D. The flow of blood into the pulmonary artery will be reduced✓
Explanation: The tricuspid valve is located on the right side of the heart and prevents backflow of blood from the right ventricle into the right atrium. If the chordae tendinae are partially non-functional, the tricuspid valve may not close properly, leading to regurgitation of blood from the right ventricle into the right atrium. This can result in a reduction of blood flow into the pulmonary artery, which carries blood from the right ventricle to the lungs.
Why the other options are wrong
- A. This option is not directly related to the tricuspid valve or the chordae tendinae. The aorta is a major artery that carries oxygenated blood from the left ventricle of the heart to the rest of the body. Issues with the tricuspid valve would not directly impact the flow of blood into the aorta.
- B. The 'pacemaker' refers to the sinoatrial (SA) node, which is responsible for initiating the electrical signals that regulate the heart's rhythm. Damage to the chordae tendinae of the tricuspid valve would not directly affect the function of the SA node, which is located in the right atrium.
- C. This option is not accurate. The tricuspid valve is located between the right atrium and right ventricle, so damage to its chordae tendinae would affect the flow of blood between these two chambers, not into the left atrium.
Q47. Which two of the following changes (i-iv) usually tend to occur in the plain dwellers when they move to high altitudes (3,500 m or more)? (i) Increase in red blood cell size (ii) Increase in red blood cell production (iii) Increased breathing rate (iv) Increase in thrombocyte count Changes occurring are?
- A. (ii) and (iii)✓
- B. (iii) and (iv)
- C. (i) and (iv)
- D. (i) and (ii)
Explanation: (ii) Increase in red blood cell production: When individuals move to high altitudes, there is a decrease in the availability of oxygen. As a response, the body increases the production of red blood cells to enhance oxygen-carrying capacity and improve oxygen delivery to tissues. (iii) Increased breathing rate: At higher altitudes, the partial pressure of oxygen in the air is lower, leading to reduced oxygen uptake in the lungs. To compensate for this, the body increases the breathing rate, allowing more oxygen to be taken in and delivered to the tissues.
Why the other options are wrong
- B. (iii) Increased breathing rate: This option is correct. Increased breathing rate is a common physiological response to high altitudes to compensate for reduced oxygen availability. (iv) Increase in thrombocyte count: Thrombocytes (platelets) are involved in blood clotting and wound healing. While some changes in blood components can occur at high altitudes, a significant increase in thrombocyte count is not a characteristic response.
- C. (i) Increase in red blood cell size: This change is not a typical response to high altitudes. Red blood cell size is not a major factor affected by altitude change. (iv) Increase in thrombocyte count: This option is not a commonly observed response to high altitudes. Thrombocyte count does not typically increase in response to altitude changes.
- D. (i) Increase in red blood cell size: This option is not a typical change associated with moving to high altitudes.(ii) Increase in red blood cell production: This option is correct. Increased red blood cell production is a well-documented response to high altitudes to improve oxygen transport.
Q48. The fastest distribution of some injectable material/medicine and with no risk of any kind, can be achieved by injecting it into the:
- A. Capillaries
- B. Arteries
- C. Veins✓
- D. Lymph vessels
Explanation: Yes, the fastest distribution of an injectable material or medicine is achieved by injecting it into the veins. This is because veins are blood vessels that carry blood back to the heart. The blood in the veins is under pressure, which helps to push the medicine throughout the body quickly. Veins are blood vessels that carry blood back to the heart. They are typically thin-walled and have valves that prevent blood from flowing backwards.
Why the other options are wrong
- A. No, the fastest distribution of some injectable material/medicine and with no risk of any kind cannot be achieved by injecting it into capillaries. Capillaries are the smallest blood vessels in the body. They are located in the tissues and are responsible for the exchange of oxygen and nutrients between the blood and the cells. Injecting material into capillaries would not result in the fastest distribution of the material. This is because the capillaries are very small and the material would have to travel a long distance to reach the cells.
- B. No, the fastest distribution of some injectable material/medicine and with no risk of any kind cannot be achieved by injecting it into arteries. The arteries are the blood vessels that carry blood away from the heart. They are very high-pressure vessels, and injecting material into them can be dangerous. The material could be forced into the wrong parts of the body, or it could damage the arteries themselves.
- D. No, the fastest distribution of some injectable material/medicine and with no risk of any kind cannot be achieved by injecting it into the lymph vessels. The lymph vessels are part of the lymphatic system, which is a network of vessels that carry lymph fluid throughout the body. Lymph fluid is a clear, watery fluid that contains white blood cells, proteins, and other substances.The lymph vessels are not directly connected to the bloodstream. This means that any medicine that is injected into the lymph vessels will have to travel through the lymphatic system before it can reach the bloodstream.
Q49. Given below are four statements (i-iv) regarding human blood circulatory system. (i) Arteries are thick-walled and have narrow lumen as compared to veins. (ii) Angina is acute chest pain when the blood circulation to the brain is reduced. (iii) Persons with blood group AB can donate blood to any person with any blood group under ABO system. (iv) Calcium ions play a very important role in blood clotting. Which two of the above statements is/are correct?
- A. (i) and (iv)✓
- B. (i) and (ii)
- C. (ii), (iii) and (iv)
- D. (iii), (iv) and (i)
Explanation: The correct statements (i)and (iv) are correct.(i) Arteries are thick-walled and have narrow lumen as compared to veins. Arteries are blood vessels that carry oxygenated blood away from the heart to various parts of the body. They have thick walls containing smooth muscle and elastic fibers, which allow them to withstand the high pressure generated by the heart's pumping action. Arteries also have a smaller lumen (the central opening through which blood flows) to maintain the blood pressure and ensure proper blood flow to the tissues. (iv) Calcium ions play a very important role in blood clotting.The statement about calcium ions is correct. Calcium ions play a crucial role in the process of blood clotting or coagulation. When there is an injury or damage to blood vessels, a series of complex reactions involving various clotting factors take place, ultimately leading to the formation of a blood clot to prevent excessive bleeding. Calcium ions are essential for the activation of clotting factors and the formation of a stable blood clot.
Why the other options are wrong
- B. (i) This statement is correct. Arteries are thick-walled and have narrow lumen as compared to veins.Arteries are thick-walled and have narrow lumen as compared to veins. Arteries are blood vessels that carry oxygenated blood away from the heart to various parts of the body. They have thick walls containing smooth muscle and elastic fibers, which allow them to withstand the high pressure generated by the heart's pumping action. Arteries also have a smaller lumen (the central opening through which blood flows) to maintain the blood pressure and ensure proper blood flow to the tissues.(ii) The statement regarding angina is not correct. Angina is not related to reduced blood circulation to the brain but is a condition caused by reduced blood flow to the heart muscles due to narrowed or blocked coronary arteries. It results in acute chest pain or discomfort due to inadequate oxygen supply to the heart.
- C. (ii) The statement regarding angina is not correct. Angina is not related to reduced blood circulation to the brain but is a condition caused by reduced blood flow to the heart muscles due to narrowed or blocked coronary arteries. It results in acute chest pain or discomfort due to inadequate oxygen supply to the heart. (iii) The statement about blood group AB is not correct. Persons with blood group AB are universal recipients, meaning they can receive blood from any ABO blood group. However, they cannot donate blood to any person with any blood group. Blood group AB individuals can donate blood only to other individuals with blood group AB. (iv) Calcium ions play a very important role in blood clotting.The statement about calcium ions is correct. Calcium ions play a crucial role in the process of blood clotting or coagulation. When there is an injury or damage to blood vessels, a series of complex reactions involving various clotting factors take place, ultimately leading to the formation of a blood clot to prevent excessive bleeding. Calcium ions are essential for the activation of clotting factors and the formation of a stable blood clot.
- D. (i) Arteries are thick-walled and have narrow lumen as compared to veins. Arteries are blood vessels that carry oxygenated blood away from the heart to various parts of the body. They have thick walls containing smooth muscle and elastic fibers, which allow them to withstand the high pressure generated by the heart's pumping action. Arteries also have a smaller lumen (the central opening through which blood flows) to maintain the blood pressure and ensure proper blood flow to the tissues. (iv) Calcium ions play a very important role in blood clotting.The statement about calcium ions is correct. Calcium ions play a crucial role in the process of blood clotting or coagulation. When there is an injury or damage to blood vessels, a series of complex reactions involving various clotting factors take place, ultimately leading to the formation of a blood clot to prevent excessive bleeding. Calcium ions are essential for the activation of clotting factors and the formation of a stable blood clot. (iii) The statement about blood group AB is not correct. Persons with blood group AB are universal recipients, meaning they can receive blood from any ABO blood group. However, they cannot donate blood to any person with any blood group. Blood group AB individuals can donate blood only to other individuals with blood group AB.
Q50. The propulsive movement of the gastrointestinal tract (GI tract) is:
- A. Peristalsis✓
- B. Epiglottis
- C. Antiperistalsis
- D. Anus
- E. None of these options
Explanation: Peristalsis is the contraction of muscle tissue that helps move and break down foodstuffs. The walls of the alimentary canal include layers of smooth muscle controlled by the autonomic nervous system. The alternating contraction and relaxation of these muscles is called peristalsis.
Why the other options are wrong
- B. The epiglottis is a flap-like opening that covers the trachea during swallowing.
- C. Anti-peristalsis is the process by which food is pushed out through the mouth from the stomach during vomiting, etc. During vomiting, the propulsion of food up the oesophagus and out the mouth comes from contraction of the abdominal muscles; peristalsis does not reverse in the oesophagus.
- D. Anus is the opening of the GI tract through which undigested food is defecated.
- E. This is incorrect, as option A is correct.
Q51. The following sequence of events occurs at the neuromuscular junction. Nerve impulse -> release of V -> end plate potential -> W produced in muscle fibre -> X release from sarcoplasmic reticulum -> Formation of Y -> muscle contraction. Which one of the following shows the correct sequence from V -> Y?
- A. Option A✓
- B. Option B
- C. Option C
- D. Option D
- E. Option E
Explanation: Neurotransmitters called acetylcholine (V) are released, and an action potential (W) is generated. After an action potential is generated in the muscle fibre, calcium ions (X) are released from the sarcoplasmic reticulum. Ca ions act on troponin and displace it so that myosin can attach to the sites on the actin molecule, forming an actomyosin (Y) complex for muscle contraction.
Why the other options are wrong
- B. Neurotransmitters called acetylcholine (V) are released, and an action potential (W) is generated. After an action potential is generated in the muscle fibre, calcium ions (X) are released from the sarcoplasmic reticulum. Ca ions act on troponin and displace it so that myosin can attach to the sites on the actin molecule, forming an actomyosin (Y) complex for muscle contraction.
- C. Neurotransmitters called acetylcholine (V) are released, and an action potential (W) is generated. After an action potential is generated in the muscle fibre, calcium ions (X) are released from the sarcoplasmic reticulum. Ca ions act on troponin and displace it so that myosin can attach to the sites on the actin molecule, forming an actomyosin (Y) complex for muscle contraction.
- D. Neurotransmitters called acetylcholine (V) are released, and an action potential (W) is generated. After an action potential is generated in the muscle fibre, calcium ions (X) are released from the sarcoplasmic reticulum. Ca ions act on troponin and displace it so that myosin can attach to the sites on the actin molecule, forming an actomyosin (Y) complex for muscle contraction.
- E. Neurotransmitters called acetylcholine (V) are released, and an action potential (W) is generated. After an action potential is generated in the muscle fibre, calcium ions (X) are released from the sarcoplasmic reticulum. Ca ions act on troponin and displace it so that myosin can attach to the sites on the actin molecule, forming an actomyosin (Y) complex for muscle contraction.
Q52. The diagram shows some organs of the digestive system. Where is amylase present?
- A. 1,4 and 5✓
- B. 1,2 and 3
- C. 2,6 and 4
- D. 3,5 and 4
Explanation: Amylase is mostly present in the mouth, in pancreatic juice, and ileum; hence, option A is correct. Amylase is not present in the liver, no enzyme is present in the large intestine and only pepsin (protease) is present in the stomach. That is why, all other options B, C and D are wrong.
Why the other options are wrong
- B. Amylase is not present in the stomach and liver. So, it is the wrong option.
- C. Amylase is not present in the stomach and large intestine. So, it also will be the wrong option.
- D. Amylase is not present in liver. So, it is the wrong option.
Q53. Which of the following is correctly matched?
- A. AF, BG, CJ, DI, EH
- B. AH, BI, DF, CG, EJ✓
- C. AJ, BI, CH, DG, EF
- D. AH, BF, DG, CI, EJ
Explanation: To solve this quickly just match one or two organelles to their correct function,crossing out the wrong options while doing so. Peroxisomes carry out detoxification of alcohol which is only in option B so we can easily choose it,no other options have DF. To check others, we know that smooth ER deals with cholesterol and fats that is why E goes with J.Ribosomes carry out protein synthesis.Centrioles form astral rays.Lysosomes destroy foreign particles.Hence,AH, BI, DF, CG, EJ is correct.
Why the other options are wrong
- A. Option A is incorrect as all of the options are mismatched.
- C. Option C is incorrect as except option B, all other options are mismatched with their functions.
- D. Option D is incorrect because except option A and E, all other options are mismatched with their functions.
Q54. Which of the following statement(s) is/are correct regarding a nucleus? I.Stores wastes and other SubstancesII.Contains genetic materialIII.Helps in cellular transport systemIV.Control centre of the cell
- A. I only
- B. I&II
- C. II & III
- D. II & IV✓
- E. III & IV
Explanation: Nucleus is the control centre of the cell and stores the genetic material of the cell,so we say that statements II and IV are correct, making option D correct. Nucleus does not store wastes and other substances plus it also does not help in cellular transport system, that eliminate option A,B,C and E.
Why the other options are wrong
- A. Nucleus doesn't store wastes and any other kind of substances. Nucleus is the governor house of cell. It controls the life and activities of cells.
- B. Nucleus stores genetic material but doesn't store any kind of wastes . So , statement II makes option B incorrect.
- C. Nucleus doesn't help in cellular transport system. So , this option is incorrect.
- E. Nucleus is the control center of cell but does not help in cellular respiration. Thus , statement III makes option E incorrect.
Q55. In the pedigree of a family shown above, brown eyes are indicated as white circles and blue eyes as dark circles. Javeria and Juhi are twins. From this chart, it can be determined that:
- A. Tahir and Mary are homozygous for brown eyes
- B. Jawaria and Juhi are identical twins
- C. Juhi is heterozygous for blue eyes
- D. Juhi is homozygous for blue eyes✓
- E. Jawaria and Saad are homozygous for brown eyes
Explanation: It is imperative for a recessive trait present in a homozygous state to show up in phenotype so answer D is correct.
Why the other options are wrong
- A. Option A is wrong because if they would have been homozygous then they couldn't produce a child having blue eyes (which is a recessive trait), rather they are a confirmed case of heterozygous
- B. Option B is wrong because genotypically in identical twins not even a single gene can differ and Jawaria and Juhi have differences in genes of eye color.
- C. Option C is wrong as Juhi can not be heterozygous for blue eyes as a recessive trait should always be homozygous to be expressed in phenotype.
- E. Option E is wrong because Jawaria and Saad can be both homozygous or heterozygous for brown eyes as their parents are heterozygous. So it cannot be predicted from the diagram shown.
Q56. Choose the correct combinations of labeling the carbohydrate molecule involved in the Calvin cycle.
- A. A - RuBP, B - Triose phosphate, C - PGA
- B. A - PGA, B - RuBP, C - Triose Phsophate
- C. A - PGA, B - Triose Phosphate, C - RuBP
- D. A - RuBP, B - PGA, C - Triose Phosphate✓
- E. A - Triose Phosphate, B - PGA, C - RuBP
Explanation: The Calvin cycle is a metabolic pathway found in the stroma of the chloroplast in which carbon enters in the form of CO2 and leaves in the form of sugar. The cycle spends ATP as an energy source and consumes NADPH2 as reducing power for adding high energy electrons to make the sugar. In the first phase, carboxylation of RUBP takes place, which leads to the formation of 1,3-bis phosphoglycerate (PGA). PGA then gets reduced to triose phosphate (glyceraldehyde phosphate). Thus, the labelled molecules in the diagram are A- RUBP, B- PGA, C- triose phosphate. Thus, the correct answer is option D.
Why the other options are wrong
- A. As per explanation, this is incorrect.
- B. As per explanation, this is incorrect.
- C. As per explanation, this is incorrect.
- E. As per explanation, this is incorrect.
Q57. The prolactin hormone, responsible for the activation of mammary glands to start producing milk, is a hormone of the:
- A. Pituitary gland✓
- B. Pancreas
- C. Thyroid gland
- D. Thymus gland
- E. Adrenal gland
Explanation: In humans, prolactin is produced both in the front portion of the pituitary gland (anterior pituitary gland) and in a range of sites elsewhere in the body. Lactotroph cells in the pituitary gland produce prolactin, where it is stored and then released into the bloodstream.
Why the other options are wrong
- B. Option B is incorrect because the pancreas produces insulin and Glucagon, but not prolactin.
- C. Option C is incorrect because the thyroid gland is responsible for producing T3 and T4.
- D. Option D is incorrect because the thymus gland releases several hormones, including thymosin.
- E. Option E is incorrect because the adrenal gland produces a wide variety of hormones such as cortisol, aldosterone androgens, adrenaline, epinephrine, and norepinephrine.
Q58. The Law of Dominance Is illustrated in the garden pea by:
- A. Homozygous tall x heterozygous tall
- B. Heterozygous tall x heterozygous tall
- C. Homozygous tall x homozygous tall
- D. Pure short x pure short
- E. Homozygous tall x pure short✓
Explanation: The Law of Dominance states that in a heterozygous individual, the dominant allele will determine the phenotype while the recessive allele is masked. In this case, the cross between a homozygous tall plant (TT) and a pure short plant (tt) clearly illustrates this law, as all offspring (Tt) will be tall, demonstrating that the dominant allele 'T' expresses itself over the recessive 't'.The other options do not adequately illustrate the Law of Dominance: the first option shows both parents expressing the tall phenotype, while the second option leads to a mix of phenotypes. The third option results in only tall offspring, but both parents are homozygous dominant, failing to demonstrate dominance. The fourth option produces only short offspring, which lacks any dominant allele.
Why the other options are wrong
- A. This cross (TT x Tt) will produce offspring that are all tall, but it does not clearly illustrate the dominance of one allele over another since both parents exhibit the tall phenotype.
- B. This cross (Tt x Tt) will produce a mix of tall and short offspring (TT, Tt, and tt), demonstrating the segregation of alleles but not the direct influence of the dominant allele in a clear way.
- C. This cross (TT x TT) will produce only tall offspring, but it does not showcase the concept of dominance since both parents are homozygous dominant.
- D. This cross (tt x tt) will produce only short offspring, which does not illustrate dominance because there are no dominant alleles present to express.
Q59. Identify the incorrect statement about Charles Darwin’s theory:
- A. The individual of species have variations among them.
- B. There is always a tendency of over reproduction in a species.
- C. Vast gradual changes result in the origin of a new species.
- D. Favorable variations survive and unfavorable will be exterminated.
- E. Intra-specific competition occurs between different species and interspecific competition occurs among the individuals in a species.✓
Explanation: Option E has a factually incorrect statement. “Intraspecific” competition means competition between individuals of the same species.” Interspecific” competition means competition between two different species.
Why the other options are wrong
- A. Option A corresponds to point number 2, hence it is not incorrect.
- B. Option B corresponds to point number 1, hence it is not incorrect.
- C. Option C corresponds to point number 5, hence it is not incorrect.
- D. Option D corresponds to point number 4, hence it is not incorrect.
Q60. In which model do proteins float in membrane like icebergs in sea:
- A. Lock and key model
- B. Induced fit model
- C. Fluid mosaic model✓
- D. Lotka volterra model
- E. All of these
Explanation: As per the fluid mosaic model cell membranes have proteins as icebergs in a sea of lipids (lipid). Hence option C is correct.
Why the other options are wrong
- A. Option A is incorrect because the lock and key model is the model used to explain the mode of action of enzymes.
- B. Option B is incorrect because the induced fit model is another model used to explain the mode of action of enzymes, in which enzymes do not behave as rigid locks but can instead modify their shapes to ensure that they fit well around substrates.
- D. Option D is incorrect because the Lotka–Volterra model is a model that can theoretically predict the outcome of interspecific competition between two species.
- E. This option is incorrect.
Q61. In the Hardy - Weinberg principle, p2 + 2pq + q2 = 1. q2 represents the frequency of the:
- A. Homozygous dominant
- B. Heterozygous dominant
- C. Heterozygous recessive
- D. Homozygous recessive✓
- E. Blended genes
Explanation: q2 represents the homozygous recessive trait in the Hardy-Weinberg principle.It is calculated by squaring the frequency of the recessive allele q, where q is the frequency of the recessive allele and p is the frequency of the dominant allele. The entire equation is p2+2pq+q2 where p2 is the homozygous dominant frequency and 2pq is the heterozygous frequency.
Why the other options are wrong
- A. A is incorrect because p² is the frequency of homozygous dominant not q².
- B. B is incorrect because heterozygous cannot be dominant or recessive.
- C. C is incorrect because heterozygous cannot be dominant or recessive.
- E. E is incorrect because q² is not the frequency of blended genes.
Q62. Ileum is about _ long:
- A. 3.6 centimeters
- B. 3.6 millimeters
- C. 3.6 inches
- D. 3.6 meters✓
- E. 3.6 kilometers
Explanation: The ileum is about 3.6 meters (11.5 feet) long (or about three-fifths the length of the small intestine) and extends from the jejunum (the middle section of the small intestine) to the ileocecal valve, which empties into the colon (large intestine).
Why the other options are wrong
- A. a) 3.6 centimeters (cm) and b) 3.6 millimeters (mm): These are microscopic or very small measurements, comparable to the diameter of the ileum (around 2.5-3 cm) or the thickness of its wall (1.5 mm), not its entire length. The ileum needs significant length to provide a large surface area for absorbing nutrients and water from digested food.
- B. a) 3.6 centimeters (cm) and b) 3.6 millimeters (mm): These are microscopic or very small measurements, comparable to the diameter of the ileum (around 2.5-3 cm) or the thickness of its wall (1.5 mm), not its entire length. The ileum needs significant length to provide a large surface area for absorbing nutrients and water from digested food.
- C. This is roughly 9 cm, which is still much too short. Even the shortest part of the small intestine, the duodenum, is around 20-25 cm long.
- E. This is an enormous distance (over 2 miles) and is a completely unrealistic length for any organ within the human body.
Q63. Haemoglobin carries more oxygen than plasma by:
- A. 50 times
- B. 20 times
- C. 70 times✓
- D. 100 times
Explanation: Hemoglobin significantly enhances the oxygen-carrying capacity of blood by approximately 70 times compared to plasma. Hemoglobin, found in red blood cells, binds and transports oxygen efficiently, with each gram carrying about 1.34 mL of oxygen. Given the typical hemoglobin concentration of 15 g/dL in blood, this results in roughly 20 mL of oxygen per 100 mL of blood, far surpassing the minimal oxygen dissolved in plasma.
Why the other options are wrong
- A. This option is incorrect. While hemoglobin significantly enhances oxygen transport, the factor is not 50 times. It carries much more oxygen compared to plasma. Each gram of hemoglobin can bind about 1.34 mL of oxygen, making it extremely efficient at transporting oxygen. In total, hemoglobin carries around 20 mL of oxygen per 100 mL of blood, compared to only about 0.3 mL carried by plasma alone. This makes hemoglobin roughly 70 times more effective than dissolved oxygen in plasma.
- B. This option is incorrect. Hemoglobin's oxygen-carrying capacity is much greater, approximately 70 times that of plasma.
- D. This option is incorrect. Although hemoglobin significantly increases oxygen transport, the enhancement is not as high as 100 times compared to plasma.
Q64. Deficient production of hormones by adrenal glands results in:
- A. Cushing's syndrome
- B. Addison's disease✓
- C. Diabetes Mellitus
- D. Goiter
- E. Epilepsy
Explanation: Addison's disease is the result of insufficient production of hormones from the adrenal glands, particularly cortisol and aldosterone. This condition leads to symptoms such as fatigue, muscle weakness, and low blood pressure. Cushing's syndrome, in contrast, is caused by excessive cortisol. Diabetes Mellitus involves insulin issues and not adrenal hormones. Goiter relates to thyroid gland issues, and epilepsy is a neurological disorder, both unrelated to adrenal insufficiency.
Why the other options are wrong
- A. Cushing's syndrome occurs when the body produces too much cortisol, often due to prolonged use of corticosteroid medications or tumors that increase cortisol production.
- C. Diabetes Mellitus is a metabolic disorder characterized by high blood sugar levels over a prolonged period, due to insulin production or action issues, not related to adrenal hormones.
- D. Goiter is the enlargement of the thyroid gland, usually due to iodine deficiency or thyroid dysfunction, and is unrelated to the adrenal glands.
- E. Epilepsy is a neurological disorder marked by recurrent seizures, and is unrelated to hormone production by the adrenal glands.
Q65. In the pea plants, the factors round and yellow seeds (RRYY) is dominant over wrinkled and green seeds (rryy). Keeping this in mind, identify the seed that has the genotype round and green.
- A. RRyy✓
- B. rrYy
- C. RrYy
- D. RRYy
Explanation: The genotype RRyy produces round and green seeds. The 'RR' indicates the presence of the dominant trait for round seeds, while 'yy' indicates the recessive trait for green seeds. Other options either contain the recessive 'rr' indicating wrinkled seeds or 'YY' or 'Yy' indicating yellow seeds, which does not match the requirement for round and green seeds.
Why the other options are wrong
- B. Option B is incorrect. The genotype 'rrYy' results in wrinkled and yellow seeds because 'rr' is the recessive trait for wrinkled seeds, and 'Yy' contains the dominant yellow trait.
- C. Option C is incorrect. The genotype 'RrYy' results in round and yellow seeds because both 'Rr' and 'Yy' contain dominant traits for round and yellow seeds, respectively.
- D. Option D is incorrect. The genotype 'RRYy' results in round and yellow seeds due to the presence of dominant traits in both 'RR' for round and 'Yy' for yellow seeds.
Q66. Lysosomes function in:
- A. Protein synthesis
- B. Processing of cellular materials
- C. Intracellular digestion✓
- D. Lipid synthesis
- E. Carbohydrate synthesis
Explanation: Lysosomes are specialized organelles within the cell that contain hydrolytic enzymes capable of breaking down macromolecules like proteins, nucleic acids, lipids, and carbohydrates. Their primary function is intracellular digestion, where they degrade and recycle cellular waste, damaged organelles, and material ingested by the cell. Unlike ribosomes, lysosomes do not synthesize proteins, and they are not involved in lipid or carbohydrate synthesis, which occur in other organelles. Options such as 'protein synthesis', 'lipid synthesis', and 'carbohydrate synthesis' refer to processes that take place outside of lysosomes, highlighting their specialized role in cellular maintenance through digestion.
Why the other options are wrong
- A. Protein synthesis occurs in the ribosomes, not in lysosomes. Ribosomes translate genetic information into proteins, a process separate from the digestive function of lysosomes.
- B. While lysosomes process materials by breaking them down, their primary function is to degrade and recycle cellular waste, rather than processing it in a constructive manner.
- D. Lipid synthesis occurs in the endoplasmic reticulum and Golgi apparatus, not in lysosomes which are dedicated to digestion and recycling.
- E. Carbohydrate synthesis is carried out by specific enzymes in the cytoplasm, while lysosomes focus on breaking down and recycling cellular waste.
Q67. A _ is a junction between two neurons or between a motor neuron and a muscle cell.
- A. Impulse
- B. Synapse✓
- C. Axon
- D. Cleft
Explanation: In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. It can be visualized as a gap between two neurons; however, that gap isn't referred to as a synapse, but rather the gap, also known as the synaptic cleft, alongside the end of the pre-synaptic neuron and the start of the post-synaptic neuron is collectively known as the synapse. Option B is hence correct.
Why the other options are wrong
- A. Impulses are the signal that travels along the length of a nerve fiber in the form of action potentials and ends in the release of neurotransmitters. Option A is therefore incorrect.
- C. Axon, also called a nerve fiber, is a portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. A neuron typically has one axon that connects it with other neurons or with muscle or gland cells. You can remember A for Away. Option C is, hence, incorrect.
- D. A (synaptic) cleft, as mentioned earlier, is just a gap between the pre-synaptic and post-synaptic membranes. Since this is not a junction, Option D is also incorrect.
Q68. The lymph vessels empty into:
- A. Arteries
- B. Veins✓
- C. Capillaries
- D. None of the given options
Explanation: Lymph drains into subclavian veins, returning lymph to the bloodstream, maintaining fluid balance and immunity.
Why the other options are wrong
- A. Arteries are blood vessels that carry oxygenated blood away from heart. Thus, lymph vessels don't empty into arteries.
- C. Capillaries are sites of exchange between arteries and veins, not drainage points.
- D. This option is incorrect because option B is correct.
Q69. Which of the following is not the function of the cerebrum?
- A. Voluntary digestion✓
- B. Thinking
- C. Intelligence
- D. Skeletal muscles
Explanation: Functions of the cerebrum include initiation of movement, coordination of movement, temperature, touch, vision, hearing, judgment, reasoning, problem-solving, emotions, and learning, which do not involve digestion. Digestion is controlled by the autonomic nervous system- it is not a voluntary function!
Why the other options are wrong
- B. The cerebrum is heavily involved in thinking processes. It is responsible for complex cognitive functions, including reasoning, problem-solving, decision-making, and creativity.
- C. Intelligence is closely related to the functions of the cerebrum. The cerebrum, particularly the cerebral cortex, is responsible for higher-order thinking and intellectual abilities.
- D. The cerebrum is involved in the voluntary control of skeletal muscles. It sends signals through the motor cortex to initiate and coordinate voluntary movements.
Q70. The spinal nerves are functionally:
- A. Sensory nerves
- B. Motor nerves
- C. Mixed nerves✓
- D. Unknown
Explanation: The cell bodies of the sensory neurons are in the dorsal root ganglion, but the motor neuron cell bodies are in the grey matter. The two roots join to form the spinal nerve just before the nerve leaves the vertebral column. Because all spinal nerves have both sensory and motor components, they are mixed nerves.
Why the other options are wrong
- A. Option A is incorrect as sensory nerves are not mixed nerves.
- B. Option B is incorrect as motor nerves are not mixed nerves.
- D. Option D is incorrect as unknown is not the answer.
Q71. What are the functions of the inter, motor and sensory neurons in a reflex response?
- A. Option A✓
- B. Option B
- C. Option C
- D. Option D
Explanation: To relay nerve impulses from within the CNS, interneurons are used. To conduct the nerve impulses from the CNS to the effector, motor neurons are used. To conduct the nerve impulses from the receptors to the CNS, sensory neurons are used.
Why the other options are wrong
- B. Functions of sensory neurons: Sensory neurons are the nerve cells that are activated by sensory input from the environment - for example, when you touch a hot surface with your fingertips, the sensory neurons will be the ones firing and sending off signals to the rest of the nervous system about the information they have received. Functions of Motor Neurons: Motor neurons of the spinal cord are part of the central nervous system (CNS) and connect to muscles, glands, and organs throughout the body. These neurons transmit impulses from the spinal cord to skeletal and smooth muscles (such as those in your stomach), and so directly control all of our muscle movements. Functions of interneurons: As the name suggests, interneurons are the ones in between - they connect the spinal motor and sensory neurons. As well as transferring signals between sensory and motor neurons, interneurons can also communicate with each other, forming circuits of various complexity.
- C. Functions of sensory neurons: Sensory neurons are the nerve cells that are activated by sensory input from the environment - for example, when you touch a hot surface with your fingertips, the sensory neurons will be the ones firing and sending off signals to the rest of the nervous system about the information they have received. Functions of Motor Neurons: Motor neurons of the spinal cord are part of the central nervous system (CNS) and connect to muscles, glands, and organs throughout the body. These neurons transmit impulses from the spinal cord to skeletal and smooth muscles (such as those in your stomach), and so directly control all of our muscle movements. Functions of interneurons: As the name suggests, interneurons are the ones in between - they connect the spinal motor and sensory neurons. As well as transferring signals between sensory and motor neurons, interneurons can also communicate with each other, forming circuits of various complexity.
- D. This option is incorrect. Functions of sensory neurons: Sensory neurons are the nerve cells that are activated by sensory input from the environment - for example, when you touch a hot surface with your fingertips, the sensory neurons will be the ones firing and sending off signals to the rest of the nervous system about the information they have received. Functions of Motor Neurons: Motor neurons of the spinal cord are part of the central nervous system (CNS) and connect to muscles, glands, and organs throughout the body. These neurons transmit impulses from the spinal cord to skeletal and smooth muscles (such as those in your stomach), and so directly control all of our muscle movements. Functions of interneurons: As the name suggests, interneurons are the ones in between - they connect the spinal motor and sensory neurons. As well as transferring signals between sensory and motor neurons, interneurons can also communicate with each other, forming circuits of various complexity.
Q72. How many meninges cover the human brain?
- A. 5
- B. 4
- C. 3✓
- D. 2
- E. 1
Explanation: There are three layers of meninges around the brain and spinal cord. The outer layer, the dura mater, is tough, white fibrous connective tissue. The middle layer of meninges is the arachnoid, a thin layer resembling a cobweb with numerous threadlike strands attaching it to the innermost layer.
Why the other options are wrong
- A. This option is incorrect. The brain and spinal cord are covered by three membranes, collectively known as Meninges: the outer hard membrane (next to the cranium), the inner Pia mater (next to the brain and spinal cord), and the middle arachnoid mater.
- B. This option is incorrect. The brain and spinal cord are covered by three membranes.
- D. This option is incorrect.The brain and spinal cord are covered by three membranes, collectively known as Meninges: the outer hard membrane (next to the cranium), the inner Pia matter (next to the brain and spinal cord), and the middle arachnoid matter.
- E. This option is incorrect. The brain and spinal cord are covered by three membranes, collectively known as Meninges: the outer hard membrane (next to the cranium), the inner Pia mater (next to the brain and spinal cord), and the middle arachnoid mater.
Q73. The autonomic nervous system controls all of the following activities except:
- A. Digestion of food
- B. Heart beat
- C. Contraction of pupil of eye
- D. Thought✓
- E. Breathing rate
Explanation: The autonomic nervous system does not directly control thought processes. Thought is primarily regulated by the central nervous system, which includes the brain and spinal cord. While the autonomic nervous system can be influenced by certain thought patterns, such as stress or relaxation, it does not directly control the generation or content of thoughts.
Why the other options are wrong
- A. The autonomic nervous system (ANS) plays a crucial role in the regulation of digestion. It controls the smooth muscle contractions in the digestive tract, secretion of digestive enzymes, and the release of hormones involved in digestion. Therefore, digestion of food is indeed controlled by the autonomic nervous system.
- B. The autonomic nervous system is responsible for regulating the heartbeat. It controls the rate and force of the heart's contractions through a balance between the sympathetic and parasympathetic divisions of the ANS.
- C. The autonomic nervous system controls the constriction and dilation of the pupil of the eye. The circular muscles of the iris, known as the pupillary sphincter, are innervated by the parasympathetic division of the ANS.
- E. The autonomic nervous system controls the breathing rate by regulating the muscles involved in respiration. The respiratory centers in the brainstem receive inputs from various sensors, including chemoreceptors that detect the levels of oxygen, carbon dioxide, and pH in the blood.
Q74. Which of the following neurotransmitters function, both as neurotransmitter and hormones, decreasing our perception of pain?
- A. Epinephrine
- B. Serotonin
- C. Dopamine
- D. Endorphins✓
Explanation: Neurotransmitters are chemical messengers that transmit a message from a nerve cell across the synapse to a target cell. Hormones are chemical messengers that are secreted directly into the blood, which carries them to organs and tissues of the body to exert their functions. All the options are both, a hormone as well neurotransmitters. Epinephrine, commonly referred to as Adrenaline, relaxes the airway muscles, making it easier for the person to breathe. At the same time, it constricts blood vessels, helping to improve blood pressure. It also increases the heart rate. However, it does not decrease the response to pain. Hence Option A is rejected. Serotonin, on the other hand, is used by the body to send messages between nerve cells. It appears to play a role in mood, emotions, appetite, and digestion. As the precursor for melatonin, it helps regulate sleep-wake cycles and the body clock. Since it is not used to decrease pain response, Option B is rejected. Dopamine is a neurotransmitter that plays a role in how we feel pleasure. It's a big part of our unique human ability to think and plan. However, it plays no role in the pain response. Hence Option C is rejected. Endorphins are substances produced by the nervous system to cope with pain or stress. They are often called “feel-good” chemicals because they can act as pain relievers and happiness boosters. Hence, Option D is correct.
Why the other options are wrong
- A. Epinephrine, commonly referred to as Adrenaline, relaxes the airway muscles, making it easier for the person to breathe. At the same time, it constricts blood vessels, helping to improve blood pressure. It also increases the heart rate. However, it does not decrease the response to pain. Hence Option A is rejected.
- B. Serotonin, on the other hand, is used by the body to send messages between nerve cells. It appears to play a role in mood, emotions, appetite, and digestion. As the precursor for melatonin, it helps regulate sleep-wake cycles and the body clock. Since it is not used to decrease pain response, Option B is rejected.
- C. Dopamine is a neurotransmitter that plays a role in how we feel pleasure. It's a big part of our unique human ability to think and plan. However, it plays no role in the pain response. Hence Option C is rejected.
Q75. The following sequence of events occurs at the neuromuscular junction. nerve impulse -> release of V -> end plate potential -> W produced in muscle fibre -> X release from sarcoplasmic reticulum -> Formation of Y -> muscle contraction.Which one of the following shows the correct sequence from V -> Y?
- A. Option A✓
- B. Option B
- C. Option C
- D. Option D
- E. Option E
Explanation: The correct sequence of events at the neuromuscular junction is as follows:Nerve impulse triggers the release of Acetylcholine (V) from the presynaptic neuron.Acetylcholine binds to receptors, generating an End Plate Potential, leading to an Action Potential (W) in the muscle fiber.The Action Potential triggers the release of Calcium ions (X) from the sarcoplasmic reticulum.Calcium ions bind to regulatory proteins, allowing the formation of Actomyosin (Y) cross-bridges, leading to muscle contraction.V = Acetylcholine, W = Action Potential, X = Calcium ions, Y = Actomyosin ✅ (Correct)
Why the other options are wrong
- B. According to the given explanation, this is incorrect. because X and Y are swapped.
- C. According to the given explanation, this is incorrect. because they disrupt the correct physiological order.
- D. According to the given explanation, this is incorrect because they disrupt the correct physiological order.
- E. According to the given explanation, this is incorrect because they disrupt the correct physiological order.
Q76. The phytohormones controlling the plant movements are?
- A. Auxins
- B. Gibberellins
- C. Abscisic acid
- D. Cytokinins
- E. All of the above✓
Explanation: Phytohormones are critical for plant growth, development, and responses to stimuli. Auxins are directly involved in tropisms, which are movements towards or away from stimuli. Gibberellins, while primarily growth hormones, also influence tropic movements by modulating growth patterns. Abscisic acid is more related to stress responses but contributes to movement by regulating stomatal closure. Cytokinins affect growth and cell division, indirectly influencing movement. Thus, all these hormones together play a role in plant movements and responses.
Why the other options are wrong
- A. Auxins are crucial for plant movements like phototropism and gravitropism, which involve growth towards light and gravity. They are essential in cell elongation, making them key players in plant movement.
- B. Gibberellins aid in stem elongation and seed germination, with some influence on movements such as phototropism and gravitropism through growth regulation.
- C. Abscisic acid primarily functions in stress responses and stomatal closure, which is a form of movement. However, it is not typically associated with directional growth movements.
- D. Cytokinins promote cell division and growth, indirectly influencing movement by affecting overall plant growth and development, but not directly involved in tropisms.
Q77. Semilunar valves are not present:
- A. At the base of the pulmonary trunk
- B. At the base of the aorta
- C. In veins
- D. In the coronary arteries✓
Explanation: Semilunar valves exist only at the pulmonary trunk and aorta to prevent backflow. Coronary arteries and veins do not have valves.
Why the other options are wrong
- A. Semilunar valves are present at the base of the pulmonary trunk. These are called the pulmonary valves, and they prevent the backflow of blood from the pulmonary artery into the right ventricle during diastole.
- B. Semilunar valves are present at the base of the aorta, called the aortic valves. They prevent the backflow of blood from the aorta into the left ventricle during diastole, ensuring unidirectional blood flow out of the heart.
- C. Veins, especially in the limbs, have venous valves, which are cusps that prevent backflow of blood.
Q78. Which of the following occurs in the body in response to the secretion of Glucagon
- A. Conversion of glucose to glycogen in liver cells
- B. Decrease in blood glucose concentration
- C. Increased uptake of glucose by muscle cells
- D. Production of cyclic AMP in target cells✓
Explanation: Option D is correct. 'Glucagon' has the opposite role to 'insulin', i.e., it mobilizes blood glucose in the plasma when you’re hypoglycemic. When glucagon is released, it can perform the following tasks: Stimulating the liver to break down glycogen to be released into the blood as glucose. Activating gluconeogenesis is the conversion of amino acids into glucose. Break down stored fat (triglycerides) into fatty acids for use as fuel by cells. All of the other options, except D, explain the role of insulin and not glucagon. By simply using an elimination method, we can deduce that D is the right answer. Just a piece of additional information: The chief role of cyclic AMP in several tissues seems to be to facilitate or promote the mobilization of glucose and fatty acid reserves. In the liver, glucagon and catecholamines cause an increase in the intracellular level of cyclic AMP by stimulating adenylyl cyclase.
Why the other options are wrong
- A. Conversion of glucose to glycogen decreases blood glucose levels. It is a function of insulin.
- B. A decrease in blood glucose level is achieved with insulin.
- C. Muscle cells cause glucose to be used while doing work. It is not a function of glucagon because glucagon causes an increase in the blood glucose level.
Q79. _ is sometimes given by injection as an emergency treatment in cardiac arrest.
- A. Acetylcholine
- B. Dopamine
- C. Serotonin
- D. Epinephrine✓
Explanation: When CPR does not generate coronary perfusion of more than 15-20 mmHg, return of spontaneous circulation (ROSC) rarely or never occurs. After more than a few minutes of cardiac arrest, arterial tone collapses, and epinephrine or another vasoconstrictor is essential for restoration of cardiac activity.
Why the other options are wrong
- A. Acetylcholine is the neurotransmitter at neuromuscular junctions, at synapses in the ganglia of the visceral motor system. It is a major neurotransmitter outside the CNS, i.e., in the PNS.
- B. Dopamine is a chemical released in the brain that makes you feel good. Having the right amount of dopamine is important both for your body and your brain. Dopamine helps nerve cells to send messages to each other.
- C. Serotonin is a chemical that carries messages between nerve cells in the brain and throughout your body. Serotonin plays a key role in such body functions as mood, sleep, digestion, nausea, wound healing, bone health, and blood clotting.
Q80. The massive accumulation of blood within a tissue is called:
- A. Hemorrhage
- B. Haematoma✓
- C. Hepatoma
- D. Haemocoel
- E. Haematemesis
Explanation: A hematoma is a localized collection of blood outside vessels, usually due to vessel injury.
Why the other options are wrong
- A. Refers to excessive or uncontrolled bleeding from blood vessels, but it does not specifically describe blood accumulation within a tissue.
- C. Refers to a liver tumor (hepatic carcinoma) and is unrelated to blood accumulation in tissues.
- D. A body cavity in invertebrates where blood is present, but it is not related to blood accumulation in tissues.
- E. Hematemesis is the medical term for vomiting blood, a symptom of internal bleeding in the upper digestive tract (esophagus, stomach, duodenum) that can appear bright red or look like dark coffee grounds.
Q81. Growth movement caused in response to gravitational stimulus is called:
- A. Nutation
- B. Geotropism✓
- C. Nastic movement
- D. Tropic movement
- E. Turgor movement
Explanation: Growth movements induced by the stimulus of gravity are said to be geotropism.Nutation is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object. Nastic movements are non-directional responses to stimuli (e.g. temperature, humidity, light irradiance), and are usually associated with plants. The movement can be due to changes in turgor or changes in growth. One can define tropic movement or tropism as the directional movement of particular parts of a plant in response to environmental stimuli.Turgor movement is due to the difference of turgidity of the cells in the lower half and upper half of pulvinus (petiole of leaf).
Why the other options are wrong
- A. Nutation is a bending or oscillatory movement in plants. It can occur in stems, roots, leaves, and other plant organs.
- C. Nastic movements are non-directional plant movements that occur in response to environmental stimuli. They are usually associated with changes in turgor pressure, which causes swelling or shrinkage.
- D. Tropic movement is the growth or movement of a plant in response to a stimulus from the environment
- E. Turgor movement is a reversible change in a plant's position that's caused by changes in cell volume. This happens when the turgor pressure of specific cells changes.
Q82. The movement of plants in response to touch stimulus is called:
- A. Hydrotropism
- B. Chemotropism
- C. Geotropism
- D. Thigmotropism✓
- E. Phototropism
Explanation: Thigmotropism is a directional growth movement that occurs as a mechanosensory response to a touch stimulus. It is typically found in twining plants and tendrils; however, plant biologists have also found thigmotropic responses in flowering plants and fungi. Phototropism is movement in response to light, geotropism is movement due to gravitational forces, and chemotropism is movement in response to chemicals.
Why the other options are wrong
- A. Hydrotropism is the growth or movement of a plant in response to moisture or water stimuli.
- B. Chemotropism is a plant's growth movement in response to a chemical stimulus.
- C. Geotropism, also known as gravitropism, is the movement or growth of a plant in response to gravity.
- E. Phototropism is the orientation or movement of a plant in response to light stimuli.
Q83. Steroids consist of _ 6 membered carbon rings and one 5 membered carbon ring.
- A. Four
- B. Three✓
- C. Two
- D. Five
- E. Six
Explanation: The steroid core structure is typically composed of seventeen carbon atoms, bonded in four "fused" rings: three six-member cyclohexane rings and one five-member cyclopentane ring.
Why the other options are wrong
- A. This option is incorrect. Steroids have a total of four rings, but only three are six-membered.
- C. This option is incorrect. Steroids have more than two six-membered rings.
- D. This option is incorrect. Steroids do not contain five six-membered rings.
- E. This option is incorrect. Steroids have fewer than six six-membered rings.
Q84. Closely related species are grouped together into _ .
- A. Families
- B. Orders
- C. Phyla
- D. Kingdom
- E. Genus✓
Explanation: Closely related species are grouped together into a “Genus”.
Why the other options are wrong
- A. A family consists of multiple genera that share certain similarities. It is a broader classification than genus.
- B. An order is a higher taxonomic category that encompasses multiple families. It is broader than both genus and family.
- C. A phylum is a major taxonomic group that includes multiple classes. It is much broader than genus, family, and order.
- D. A kingdom is one of the highest levels of taxonomic classification, comprising multiple phyla. It is far broader than genus.
Q85. The cell wall of most of the bacteria have a unique macromolecule called_.
- A. Cellulose
- B. Chitin
- C. Fibres
- D. Fats
- E. Peptidoglycan✓
Explanation: A cell wall is a layer located outside the cell membrane found in plants, fungi, bacteria. Plant cell is made up of cellulose, fungi cell of chitin and bacteria cell is made up of peptidoglycan.
Why the other options are wrong
- A. CelluloseWhat it is: A polysaccharide composed of β-glucose units.Where it's found: Primarily in the cell walls of plants and some algae.Function: Provides structural support and rigidity to plant cells, not bacteria.
- B. ChitinWhat it is: A polysaccharide similar to cellulose but contains nitrogen (N-acetylglucosamine units).Where it's found: In the exoskeletons of arthropods and the cell walls of fungi.Function: Provides strength and protection, but not found in bacterial cell walls.
- C. FibresWhat they are: Thread-like structures made of various proteins or carbohydrates, depending on their origin.Types:Plant fibers like cellulose found in cotton, flax.Animal fibers like collagen found in tendons, wool.Function: Provides strength, flexibility, and structure, but not specific to bacterial cell walls.
- D. Fats (Lipids)What they are: A type of lipid used for energy storage, insulation, and forming cell membranes.Where they're found: In cell membranes, not part of the cell wall structure.Function: Essential for energy storage and insulation but not related to bacterial cell walls.
Q86. The process of replacing or supplementing the defective allele with a functional, normal allele is known as _.
- A. Allele transplant
- B. Physiotherapy
- C. Gene therapy✓
- D. Mutation
- E. Cloning
Explanation: Gene therapy is an experimental technique that uses an allele to treat or prevent disease,by replacing the defective allele. In the future, this technique may allow doctors to treat a disorder by inserting a gene into a patient's cells instead of using drugs or surgery.
Why the other options are wrong
- A. This term is not commonly used in biotechnology. Alleles can be transferred, but the process is not typically called an 'allele transplant.'
- B. Physiotherapy involves physical methods to promote health and wellness and is unrelated to genetic modification.
- D. Mutation refers to changes in the DNA sequence, which can be harmful, beneficial, or neutral, but does not involve replacing defective alleles with normal ones.
- E. Cloning creates genetically identical copies of a cell or organism and is not about replacing defective alleles.
Q87. In cats, the genes controlling coat color are co-dominant and are carried on the X chromosomes. When a black female was mated with a ginger male the resulting litter consisted of black male and tortoise-shell female kittens. What phenotypic ratio would be expected in the F2 generation?
- A. 1 black male : 1 ginger male : 2 tortoise - shell females
- B. 1 black male : 1 ginger male : 1 tortoise - shell female : 1 black female✓
- C. 2 black males : 1 tortoise - shell female : 1 ginger female
- D. 1 black male : 1 tortoise - shell female : 1 ginger female : 1 black female
- E. 2 black males : 1 tortoise - shell female : 1 black female
Explanation: A black male has a genotype of XbY Tortoise-shell female kittens will have: XbXg XbY and XbXg XbXb; XbXg; XbY; XgY Hence: 1 Black-female; 1 tortoiseshell female; 1 black male; 1 ginger male.
Why the other options are wrong
- A. This ratio suggests 50% of the offspring are black males and 25%are ginger females. For 50% to be black males, both alleles from the female would have to combine with the chromosome from the male, which is impossible since the male only passes on a allele 50% of the time. Also, a ginger female requires the female parent to contribute and the male parent to contribute, so he cannot contribute the allele. Therefore, this option is incorrect.
- C. This ratio is similar to the correct ratio (B) but incorrectly substitutes ginger male with ginger female. As established in the analysis of option C, the black male cannot pass on the allele required to create a homozygous ginger female. The genotype results in a ginger male, not a ginger female. Therefore, this option is incorrect.
- D. This ratio suggests 50% of the offspring are black males and completely omits the ginger male phenotype (X R Y). Since the F 1 tortoise-shell female (XB X R ) has an X R allele, there is a 25% chance she will pass it to a male offspring, resulting in a XR Y ginger male. Furthermore, the number of black males (XB Y) is only 25%, not 50%. Therefore, this option is incorrect.
- E. This ratio suggests 50%of the offspring are black males and completely omits the ginger male phenotype. Since the tortoise-shell female has an allele, there is a 25%chance she will pass it to a male offspring, resulting in a ginger male. Furthermore, the number of black males. Therefore, this option is incorrect.
Q88. A bean seed contains all of the following EXCEPT:
- A. A seed coat
- B. An epicotyl
- C. A hypocotyl
- D. A hypha✓
- E. Cotyledon
Explanation: A seed coat is the outer protective layer of a seed. An epicotyl is the part of the embryo that grows above the ground. A hypocotyl is the part of the embryo that grows below the ground. A cotyledon is a leaf-like structure that stores food for the embryo. A hypha is a thread-like filament that is found in fungi.
Why the other options are wrong
- A. The seed coat is the outer protective layer of a seed, shielding the embryonic plant inside.
- B. The epicotyl is a part of the plant embryo in a seed that will develop into the shoot bearing the first true leaves.
- C. The hypocotyl is the part of the embryo that becomes the stem below the seed leaves (cotyledons) and above the root.
- E. The cotyledon is a significant part of the seed, acting as a food storage structure to nourish the developing plant embryo.
Q89. Highly condensed portions of the chromatin are called:
- A. Heterochromatin✓
- B. Nucleosome
- C. Super coils
- D. None of these
Explanation: Heterochromatin represents the highly condensed portions of chromatin. This dense packing makes the DNA inaccessible to the transcription machinery, leading to a transcriptionally inactive state. In contrast, euchromatin is less condensed and allows for active gene transcription. Nucleosomes are the structural units of chromatin, and supercoiling refers to the additional twisting of the DNA helix to aid in its compaction, not its condensation state. Therefore, heterochromatin is the best answer to describe highly condensed chromatin.
Why the other options are wrong
- B. A nucleosome is the basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound around a core of histone proteins. It is not a highly condensed portion of chromatin, but rather a structural component of it.
- C. Supercoiling refers to the over-twisting or under-twisting of the DNA helix, which aids in DNA compaction. Although it contributes to DNA packaging, it describes the topology of DNA molecules rather than the condensation state of chromatin.
- D. This option is incorrect as there is a correct answer provided among the other choices.
Q90. All of the following are sexually transmitted diseases except:
- A. Syphilis
- B. Gonorrhea
- C. Alzheimer's disease✓
- D. Genital herpes
- E. AIDS
Explanation: Alzheimer's disease is not a sexually transmitted disease. It is a progressive neurodegenerative disorder unrelated to sexual activity, primarily influenced by genetic and age-related factors. In contrast, syphilis, gonorrhea, genital herpes, and HIV/AIDS are all conditions that are transmitted through sexual contact. Identifying Alzheimer's disease as the exception is key to answering this question correctly.
Why the other options are wrong
- A. Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. It spreads through sexual contact and can lead to serious health issues if left untreated.
- B. Gonorrhea is a common STI caused by the bacterium Neisseria gonorrhoeae. It is typically transmitted through sexual activities such as vaginal, anal, or oral sex.
- D. Genital herpes is a viral infection caused by the herpes simplex virus (HSV), usually HSV type 2. It is a sexually transmitted infection that can be spread through intimate contact.
- E. AIDS (Acquired Immunodeficiency Syndrome) results from infection with HIV, which is primarily transmitted through unprotected sexual contact, sharing needles, or from mother to child. While AIDS itself is not an STI, it is the result of an STI (HIV).
Q91. Electronic configuration of M2+ ion is 2, 8, 14 and its atomic mass is 56 amu. The number of neutrons in its nucleus are:
- A. 30✓
- B. 32
- C. 42
- D. 52
Explanation: Total number of electrons in M2+ ions are 2+8+14=24, since they lost two electrons to become this ion that means neutral M will have 26 electrons. Since neutral atoms have the same numbers of electrons and protons so the number of protons in M is also 26. As the question states that the mass number of M2+ is 56. Mass number, being the sum of protons and neutrons, can be used to calculate neutrons, by subtracting protons from it(56-26=30)
Why the other options are wrong
- B. Number of neutrons is 30 not 32.
- C. Number of neutrons is 30 not 42.
- D. Number of neutrons is 30 not 52.
Q92. The quantum numbers +½ and -½ for the electron spin represent:
- A. Rotation of the electron in clockwise and anticlockwise direction respectively
- B. Rotation of the electron in anticlockwise and clockwise direction respectively
- C. Magnetic movement of the electron pointing up and down respectively
- D. Two quantum mechanical spin states which have no classical analogue✓
Explanation: This is the most suitable option as it covers all aspects of describing the spin quantum number and its states.The two states +1/2 and -1/2, describes the spin of an electron. It is the term used for denoting the property of an electron only in Quantum physics and it does not have any proof in classical physics. That's why the term "no classical analogue" is used.
Why the other options are wrong
- A. Incorrect. Electron spin quantum numbers do not describe physical rotation like a planet spinning.
- B. Incorrect. The concept of electron spin does not involve literal clockwise or anticlockwise rotations.
- C. Incorrect. While electron spin does relate to magnetic properties, this description is overly simplistic and does not capture the full quantum mechanical nature.
Q93. The diagram below represents the process of:
- A. Hydrolysis
- B. Condensation✓
- C. Neutralization
- D. Metabolism
Explanation: When two monomers join together to form a single product, with the removal of H2O, the process is called the condensation process. Hence, option B is correct.
Why the other options are wrong
- A. Option A is wrong as hydrolysis is the opposite of condensation; it is the breakdown into smaller molecules by the addition of H2O.
- C. Option C is wrong as neutralization is the process by which acid neutralizes base to form salt and water.
- D. Metabolism is the breakdown of substances. That makes option D incorrect.
Q94. The basic functional unit of human kidney is
- A. Nephridia
- B. Loop of Henle
- C. Pyramid
- D. Nephron✓
Explanation: A nephron is a unit of structure and function in a kidney. A kidney contains about a million nephrons, each approximately 3 cm long. A nephron is a long tubule differentiated into four regions having different anatomical features and physiological role : Bowman’s capsule, proximal convoluted tubule (PCT), loop of Henle, and distal convoluted tubule (DCT). The latter opens into one of the collecting ducts. Nephridia are the excretory organs of annelids.
Why the other options are wrong
- A. Nephridia is the excretory organ of many invertebrates, consisting of a tubule with one end opening into the body cavity and the other opening into a pore at the body surface.
- B. The loop of Henle is a part of the Nephron in the kidneys, which helps to reabsorb water and salt from the kidney tubules.
- C. The main renal pyramid function is to collect and transport urine through almost 1.25 million nephrons in the kidneys.
Q95. The electronic configuration of iron is:
- A. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d5
- B. 1s2, 2s2, 2p6, 3s2, 3p6, 4s1, 3d5
- C. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d6✓
- D. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d3
- E. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d2
Explanation: The electronic configuration of iron (Fe) with 26 electrons is: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d6. This follows the Aufbau principle, where electrons fill orbitals starting from the lowest energy level. The 4s subshell is filled before the 3d subshell. Options A, B, D, and E account for fewer electrons than iron's 26, each missing one or more electrons in their configuration.
Why the other options are wrong
- A. Incorrect. This configuration accounts for only 25 electrons, but iron has 26 electrons. The 3d subshell should have 6 electrons.
- B. Incorrect. This configuration accounts for only 24 electrons. Iron needs a total of 26 electrons. Both 4s and 3d subshells should be completely filled to the necessary number.
- D. Incorrect. This configuration accounts for only 23 electrons. Iron requires a total of 26 electrons, with specific numbers in the 4s and 3d subshells.
- E. Incorrect. This configuration accounts for only 22 electrons. Iron's electron configuration should account for 26 electrons, with the correct distribution in the 4s and 3d subshells.
Q96. IUPAC Nomenclature of: CH3 - CH = CH - CH2 - CH = CH2 is:
- A. 2 - pentene
- B. 1, 4 - hexadiene✓
- C. 3 - methyl butane
- D. 1, 3, 5 - heptatriene
- E. 1, 3, 6 - hexatriene
Explanation: The correct IUPAC name for the compound CH3 - CH = CH - CH2 - CH = CH2 is 1,4-hexadiene. This is because the compound has a longest chain of 6 carbon atoms, indicated by the prefix 'hex'. The double bonds are located at the first and fourth carbon atoms, which is specified in the name as 1,4-diene. The other options are incorrect because they either miscount the number of carbon atoms, suggest incorrect branching, or provide inappropriate locations for the double bonds.
Why the other options are wrong
- A. Incorrect. The compound contains 6 carbon atoms, not 5, so it cannot be a pentene.
- C. Incorrect. The compound is a straight chain with no branching, and it contains 6 carbon atoms, not 4.
- D. Incorrect. The compound has only 6 carbon atoms and two double bonds, not 7 carbons and three double bonds.
- E. Incorrect. The compound contains only two double bonds, not three. Also, the numbering of the double bonds is incorrect for the given structure.
Q97. For the equilibrium reaction 2NO2 ⇌ N2O4 (g) (-61 kJ), increase of temperature would:
- A. Favour the Formation of N2O4
- B. Favour the Decomposition of N2O4✓
- C. No Effect on Equilibrium
- D. Stop the Reaction
Explanation: The reaction is exothermic (ΔH = -61 kJ) in the forward direction (2NO₂ → N₂O₄). Increasing temperature adds heat, which the system counteracts by shifting toward the endothermic reverse reaction. Thus, the equilibrium shifts to decompose N₂O₄ into NO₂.
Why the other options are wrong
- A. Option A is wrong according to given reaction conditions.
- C. Option C is wrong according to given reaction conditions.
- D. Option D is wrong according to given reaction conditions.
Q98. The chief ore of aluminium is:
- A. Na3AlF6
- B. Al2O3.nH2O
- C. Al2O3
- D. Al2O3.2H2O✓
Explanation: The chief ore of aluminium is bauxite, with the chemical formula Al2O3.2H2O. Bauxite is primarily composed of aluminium hydroxide minerals, which are processed to produce pure aluminium. The other options are related to aluminium but are not the primary ore. Cryolite (Na3AlF6) is used in the extraction process, not as an ore. Alumina (Al2O3) is a refined product derived from bauxite, while Al2O3.nH2O refers to various alumina hydrates but not specifically to bauxite.
Why the other options are wrong
- A. Na3AlF6, known as cryolite, is used as a flux in the aluminium extraction process but is not the primary ore of aluminium.
- B. Al2O3.nH2O represents alumina hydrates, which are found in bauxite, the primary ore of aluminium. However, the specific composition varies.
- C. Al2O3 is alumina, a refined form of aluminium oxide, but is not the ore itself.
Q99. Sp hybrid orbitals are formed by the mixing of:
- A. One s and two p
- B. One s and three p
- C. One s and one p✓
- D. Two s and two p
Explanation: In sp hybridization, one s orbital and one p orbital hybridize to form two sp orbitals, each consisting of 50% s character and 50% p character. This type of hybridization is required whenever an atom is surrounded by two groups of electrons.
Why the other options are wrong
- A. The hybridization of one s and two p will form sp2. So, this is not correct.
- B. The hybridization of one s and three p will form sp3. So, this is not correct.
- D. 2s and 2p orbitals can undergo sp, sp², or sp³ hybridization, depending on the molecular structure and bonding requirements.
Q100. Ethers show the phenomenon of:
- A. Position isomerism
- B. Functional group isomerism
- C. Metamerism✓
- D. Cis-trans isomerism
Explanation: Metamerism is a type of isomerism in which molecules have the same molecular formula but different alkyl groups around the functional group.For example,CH3-CH2-O-CH2-CH3 and CH3-O-CH2-CH2-CH3 are two metamers of each other.
Why the other options are wrong
- A. Compounds that can show position isomers are those with a functional group or substituent that can be attached at different positions along the carbon chain, like alcohols (e.g., propan-1-ol and propan-2-ol), alkenes (e.g., 1-butene and 2-butene), and alkyl halides (e.g., 1-chloropropane and 2-chloropropane), where the position of the functional group changes while maintaining the same carbon skeleton.
- B. Compounds that exhibit functional group isomerism include alcohols and ethers, aldehydes and ketones, and carboxylic acids and esters; essentially, any pair of compounds with different functional groups but the same molecular formula can be considered functional group isomers.
- D. Compounds that exhibit cis-trans isomerism are typically alkenes (molecules with a carbon-carbon double bond), where the carbon atoms in the double bond each have two different groups attached to them, allowing for different spatial arrangements of those groups on either side of the double bond; a common example is "but-2-ene" which can exist as both cis and trans isomers depending on the position of the methyl groups relative to each other.
Q101. The net heat change in a chemical reaction is the same whether it is brought about in two or more different ways in one or several steps. This is known as:
- A. Henry's law
- B. Hess's law✓
- C. Joule's principle
- D. Dalton's law
Explanation: Hess's Law is a fundamental principle in thermochemistry, asserting that the total enthalpy change during a chemical reaction is the same regardless of the number of steps in which the reaction is carried out, because enthalpy is a state function. This means that it depends only on the initial and final states of the system, not on the path taken.Henry's law, Dalton's law, and Joule's principle all deal with different principles: Henry's law is about gas solubility in liquids, Dalton's law is about partial pressures in gas mixtures, and Joule's principle is about the conversion of electrical energy to heat in conductors. None of these involve the calculation of enthalpy changes in chemical reactions.
Why the other options are wrong
- A. Henry's law relates to the solubility of gases in liquids and the pressure above the liquid, not to energy changes in reactions.
- C. Joule's principle deals with the conversion of electrical energy into heat, specifically in resistive materials, and is not related to chemical reaction pathways.
- D. Dalton's law pertains to the pressures of gases in a mixture, not to the enthalpy changes of chemical reactions.
Q102. Metallic character of the elements:
- A. Decreases down the groups
- B. Increases down the groups✓
- C. Remains the same across the periods
- D. Increases across the periods
Explanation: The correct answer is that metallic character increases down the groups. This is because as we move down a group in the periodic table, the atomic size increases due to the addition of electron shells. As a result, the valence electrons are further from the nucleus and experience less effective nuclear charge, making them easier to lose and thus increasing metallic character.Option A is incorrect because metallic character increases, not decreases, down a group. Option C is incorrect because metallic character decreases as we move across a period from left to right, due to increased nuclear charge attracting electrons more strongly. Option D is incorrect because metallic character does not increase across a period for the same reason.
Why the other options are wrong
- A. Metallic character does not decrease down the groups. As we descend a group, the atomic size increases, reducing the effective nuclear charge felt by valence electrons, making them easier to lose. This results in an increased metallic character.
- C. Metallic character does not remain the same across the periods. It generally decreases as we move from left to right across a period due to increasing nuclear charge which holds the electrons more tightly.
- D. Metallic character does not increase across the periods. As we move from left to right across a period, the effective nuclear charge increases, making it more difficult for atoms to lose electrons, thereby decreasing metallic character.
Q103. Tritium, an isotope of hydrogen contains:
- A. Equal number of electrons and neutrons
- B. Equal number of electrons, protons and neutrons
- C. Number of neutrons is double than the number of protons✓
- D. Number of neutrons is half than the number of protons
Explanation: Tritium is the isotope of the hydrogen having mass number 3 and proton number 1.Number of neutrons are mass number-number protons which turn out to be 2. So we can say that the number of neutrons is twice the number of protons.
Why the other options are wrong
- A. As per explanation, this is incorrect.
- B. As per explanation, this is incorrect.
- D. As per explanation, this is incorrect.
Q104. The chemical name of K2[Zn(OH)4] is:
- A. Potassium tetrahydroxyzinc (II)
- B. Potassium tetrahydroxozincate (II)✓
- C. Potassium tetrahydroxyzincate (VI)
- D. Potassium hydroxyzinc (II)
Explanation: The chemical name of K2[Zn(OH)4] is derived by naming the cation first, which is Potassium. The complex ion is named by first identifying the central metal, Zinc, which has an oxidation state of +2, indicated in Roman numerals as (II). The presence of four hydroxide ions is denoted by 'tetrahydroxo'. Therefore, the correct name for the compound is Potassium tetrahydroxozincate (II), reflecting both the coordination number and the oxidation state of zinc. Other options are incorrect because they either misrepresent the oxidation state or the number of hydroxide ions in the compound.
Why the other options are wrong
- A. Incorrect. The term 'zincate' should be used instead of 'zinc' to indicate the presence of a complex ion structure.
- C. Incorrect. The oxidation state of zinc in this compound is +2, not +6. The Roman numeral must accurately reflect the oxidation state.
- D. Incorrect. This name suggests only one hydroxide ion is present, which contradicts the formula indicating four hydroxide ions.
Q105. Paramagnetic elements contain:
- A. All paired electrons
- B. All unpaired electrons
- C. Few unpaired electrons.✓
- D. Unequal electrons and protons
Explanation: Paramagnetic elements are those with one or more unpaired electrons. These unpaired electrons create a net magnetic moment, making the element attracted to an external magnetic field. Option C is correct because it acknowledges the presence of unpaired electrons, which is the primary cause of paramagnetism. Option A is incorrect because paired electrons result in diamagnetism, not paramagnetism. Option B is misleading as it implies that all electrons must be unpaired for paramagnetism, which is not true. Even one unpaired electron can result in paramagnetism. Option D is unrelated to paramagnetism; it describes ions, which have an imbalance of electrons and protons, resulting in a charge.
Why the other options are wrong
- A. Elements with all paired electrons are diamagnetic, not paramagnetic, as they do not have unpaired electrons to create a magnetic moment.
- B. While having unpaired electrons is a characteristic of paramagnetic materials, it is not necessarily true that all electrons are unpaired. Even one unpaired electron can result in paramagnetism.
- D. This refers to ions rather than paramagnetic elements. The number of electrons and protons does not determine paramagnetism directly.
Q106. The mass of an electron is:
- A. 1.008 amu
- B. 1.009 amu
- C. 0.000550 amu✓
- D. 0.5500 amu
Explanation: The mass of an electron is approximately 0.000550 amu, which is much smaller compared to the masses of protons and neutrons (approximately 1 amu each). This small mass is due to the electron's relatively lower contribution to the overall mass of an atom. The incorrect options suggest masses closer to those of protons and neutrons, highlighting the importance of distinguishing between the masses of different subatomic particles.
Why the other options are wrong
- A. Incorrect Answer. This is approximately the mass of a proton or neutron, not an electron.
- B. Incorrect Answer. This value is close to that of a proton or neutron, not an electron.
- D. Incorrect Answer. This value is much too large for an electron and closer to the mass of a proton or neutron.
Q107. SN2 reactions can be best carried out with:
- A. Primary alkyl halides✓
- B. Secondary alkyl halides
- C. Tertiary alkyl halides
- D. Both primary and tertiary alkyl halides
Explanation: SN2 reactions involve a nucleophilic attack on the electrophilic carbon, leading to the inversion of configuration. The reaction is sensitive to steric hindrance around the electrophilic center. Therefore, primary alkyl halides are most suitable for SN2 reactions as they present the least steric congestion, allowing for efficient backside attack by the nucleophile. In contrast, secondary alkyl halides present moderate steric hindrance, making SN2 reactions possible but less favorable compared to primary halides. Tertiary alkyl halides are too sterically hindered for SN2 reactions and instead undergo SN1 reactions. Thus, primary alkyl halides are the best choice for SN2 reactions.
Why the other options are wrong
- B. While secondary alkyl halides can undergo SN2 reactions, they do so more slowly than primary alkyl halides due to increased steric hindrance.
- C. Tertiary alkyl halides are highly hindered and typically undergo SN1 reactions instead of SN2 reactions.
- D. Only primary alkyl halides favor SN2 reactions due to minimal steric hindrance, while tertiary favor SN1.
Q108. Which one of the following is NOT a nucleophile?
- A. H2S
- B. BF3✓
- C. NH3
- D. CN-
Explanation: A nucleophile is an electron-rich species capable of donating electron pairs to electron-deficient species. In contrast, electrophiles are electron-deficient and seek electrons. BF₃ is not a nucleophile because it is electron-deficient and acts as an electrophile, accepting electron pairs into its vacant orbital. H₂S, NH₃, and CN⁻ all have lone pairs of electrons that enable them to act as nucleophiles by donating electrons in reactions.
Why the other options are wrong
- A. (a) H₂S - NucleophileSulfur in H₂S has lone pairs of electrons and is less electronegative than oxygen, making it a good nucleophile.It can effectively donate its lone pair in nucleophilic reactions.
- C. (c) NH₃ - NucleophileNitrogen in NH₃ has a lone pair of electrons that it can donate in nucleophilic reactions.This ability to donate electrons makes ammonia a good nucleophile.
- D. (d) CN⁻ - Strong NucleophileCN⁻ (cyanide ion) carries a negative charge and has a lone pair on carbon.The negative charge greatly enhances its ability to donate electrons, making it a very strong nucleophile.
Q109. The oxidation number of Nitrogen in HNO3 is:
- A. +4
- B. +2
- C. +6
- D. +5✓
- E. +7
Explanation: In HNO₃, hydrogen is +1 and each oxygen is –2. Total must equal zero: +1+x+3(−2)=0. Solving gives x=+5, so nitrogen has oxidation number +5.
Why the other options are wrong
- A. This option is incorrect. The oxidation number of Nitrogen in HNO3 is not +4.
- B. This option is incorrect. The oxidation number of Nitrogen in HNO3 is not +2.
- C. This option is incorrect. The oxidation number of Nitrogen in HNO3 is not +6.
- E. This option is incorrect. The oxidation number of Nitrogen in HNO3 is not +7.
Q110. The unit of rate of reaction is:
- A. Mole (dm3) sec
- B. Mole (dm3) sec-1
- C. Mole(dm-3) sec -1✓
- D. Mole(dm3) sec-2
- E. Mole (dm3)-1 sec -2
Explanation: Reaction rates are usually expressed as the concentration of reactant consumed or the concentration of product formed per unit time. The units are thus moles per decimeter cube per unit time [Mole (dm-3) sec-1 ].
Why the other options are wrong
- A. Incorrect as it doesn't involve the concept of time (sec) in the unit of rate.
- B. Incorrect because the rate is typically expressed as concentration per unit time, so sec-1 represents 1/second, which means change in concentration per second.
- D. Incorrect as it includes a second-order term (sec-2) in the unit, which doesn't represent the rate of a reaction.
- E. Incorrect because it includes an inverse term for volume (dm3)-1, which doesn't represent the unit for rate.
Q111. The chemical properties of Sulphuric Acid is/are:
- A. Acidic properties
- B. Oxidizing properties
- C. Dehydrating properties
- D. Sulfonating properties
- E. All of these✓
Explanation: Sulfuric acid is a multi-functional chemical with a range of properties:Acidic properties: As a strong acid, sulfuric acid dissociates completely in water, releasing H+ ions, which are responsible for its acidic nature.Oxidizing properties: In redox reactions, sulfuric acid can act as an oxidizing agent, accepting electrons from other substances.Dehydrating properties: Sulfuric acid can remove water from other compounds, a process evident in its interactions with organic materials like carbohydrates.Sulfonating properties: Its ability to add sulfonate groups to organic compounds is crucial for producing sulfonated derivatives.Therefore, the correct answer is All of these, as sulfuric acid exhibits all these chemical properties. Each of the individual options represents just one aspect of its chemical behavior.
Why the other options are wrong
- A. Sulfuric acid is a strong acid that fully ionizes in water, releasing hydrogen ions (H+). This characteristic gives it its acidic properties, as it can donate protons to other substances, particularly bases, forming salts.
- B. Sulfuric acid acts as an oxidizing agent in certain reactions by accepting electrons from other substances, thereby undergoing a reduction process itself. This property is evident in its ability to oxidize metals and non-metals.
- C. As a dehydrating agent, sulfuric acid has a strong affinity for water. It can remove water from other compounds, such as sugars, converting them into carbon and water vapor, while it itself remains undissolved.
- D. In concentrated form, sulfuric acid can introduce sulfonate groups into organic molecules, a process known as sulfonation. This makes it a valuable reagent in the chemical industry for creating sulfonated compounds.
Q112. Benzene can be prepared from:
- A. From Petroleum
- B. From Coal
- C. From Acetylene
- D. From Phenol
- E. All of these✓
Explanation: The correct answer is that benzene can be prepared from all the mentioned sources. Petroleum: Benzene is obtained through catalytic reforming and steam cracking of naphtha, which are standard industrial processes for hydrocarbon refinement. Coal: During the carbonization of coal, benzene is one of the volatile compounds distilled from coal tar. Acetylene: Acetylene undergoes cyclic polymerization at high temperatures, forming benzene as a result. Phenol: Reduction of phenol using zinc dust is another chemical method to synthesize benzene, with zinc oxide as a byproduct. Thus, each method demonstrates a valid approach to benzene production.
Why the other options are wrong
- A. Benzene can be derived from petroleum through processes such as catalytic reforming and steam cracking of naphtha. These methods involve refining lighter fractions of crude oil to yield benzene as a byproduct.
- B. Coal tar, a byproduct of coal carbonization, contains benzene. Through fractional distillation, benzene and other aromatic compounds are separated from coal tar at specific temperature ranges.
- C. Acetylene (ethyne) can be converted to benzene by cyclic polymerization. This process involves passing acetylene through a red-hot tube at high temperatures, leading to the formation of the benzene ring.
- D. Benzene can be obtained from phenol by reducing it with zinc dust. The reaction involves the reduction of phenol to form benzene and zinc oxide as a byproduct.
Q113. - ROR is the nucleophile of
- A. Alcohols
- B. Esters
- C. Cyanides
- D. Ethers✓
- E. Aldehydes
Explanation: We have to look at the general form of given functional groups.
Why the other options are wrong
- A. For alcohol it must be ROH
- B. For esters, it must be R-COO-R
- C. For cyanides, it must be CN-
- E. For aldehydes, it must be RCHO
Q114. Primary Alcohol is produced by reactions of Grignard's reagent with _ followed by hydrolysis in an acidic medium.
- A. Carbon dioxide
- B. Formaldehyde✓
- C. Acetaldehyde
- D. Ketone
- E. Methyl chloride
Explanation: The Grignard Reaction involves the addition of an organomagnesium halide (Grignard reagent) to carbonyl compounds. When Grignard reagents react with formaldehyde, a primary alcohol is produced upon hydrolysis in an acidic medium. Formaldehyde is unique as it is the simplest aldehyde, thus allowing the formation of a primary alcohol. Other aldehydes and ketones lead to secondary and tertiary alcohols, respectively. Carbon dioxide reacts with Grignard reagents to form carboxylic acids, not alcohols, and methyl chloride does not react to form an alcohol.
Why the other options are wrong
- A. Grignard reagents react with carbon dioxide followed by acidic hydrolysis to produce carboxylic acids, not primary alcohols. The reaction adds a carbon atom to the original chain.
- C. Reacting a Grignard reagent with acetaldehyde or any aldehyde other than formaldehyde results in a secondary alcohol, not a primary alcohol.
- D. Grignard reagents react with ketones to form tertiary alcohols after acidic hydrolysis, not primary alcohols.
- E. Methyl chloride does not undergo a reaction to form an alcohol in the presence of a Grignard reagent. It serves as a precursor in the formation of the Grignard reagent itself.
Q115. If the reaction, P + Q → R + S, is described as being of zero-order with respect to P, it means that:
- A. P is a catalyst in this reaction
- B. No P molecules possess sufficient energy to react
- C. The concentration of P does not change during the reaction
- D. The rate of reaction is independent of the concentration of P✓
- E. The rate of reaction is proportional to the concentration of Q
Explanation: If the order of reaction with respect to P is 0 (zero), this means that the concentration of P doesn't affect the rate of reaction. Mathematically, any number raised to the power of zero (x0) is equal to 1. That means that that particular term disappears from the rate equation.
Why the other options are wrong
- A. P is a reactant in this reaction, not a catalyst. A catalyst is a substance that speeds up a reaction without being consumed, which is not the case for P.
- B. This statement is incorrect because the reaction occurs, indicating that P molecules do possess sufficient energy for effective collisions and to form products.
- C. While the rate is independent of P's concentration, the concentration of P actually decreases as it is consumed in the reaction.
- E. This cannot be determined from the information given. The dependence on Q's concentration requires experimental data to establish the reaction order with respect to Q.
Q116. The oxidation number of all the elements in the free state is:
- A. 1
- B. 3
- C. 0✓
- D. -1
- E. -3
Explanation: All the elements have an oxidation number of 0 in the free state.
Why the other options are wrong
- A. The oxidation number of 1 applies to elements in compounds where they typically lose or gain one electron, such as in Na+ or Cl-. In the free state, elements are neutral.
- B. An oxidation number of 3 can be found in elements that typically gain or lose three electrons in compounds, such as Fe3+. However, in the free state, elements do not exhibit this behavior.
- D. An oxidation number of -1 is typical for elements like halogens in compounds where they gain one electron, such as Cl-. Free state elements do not gain or lose electrons.
- E. Elements with an oxidation number of -3 generally gain three electrons in compounds, such as nitrogen in NH3. In the free state, elements maintain a neutral charge.
Q117. 2 grams of H2 molecules contain _ molecules.
- A. 12.04 x 1023
- B. 6.02 x 1023✓
- C. 3.01 x 1023
- D. 1.008
- E. 2
Explanation: 1 mole of hydrogen contains = 2×1 = 2g2g of H2 contain = 2/2 × avogadro number = 1 × 6.022 × 10²³ = 6.022 × 10²³ molecules.
Why the other options are wrong
- A. This option is incorrect. This value suggests twice the number of molecules in 2 grams of H2, which is not correct as only 1 mole of H2 is present.
- C. This option is incorrect. This value represents half of Avogadro's number, which would correspond to half a mole of H2, not the full 2 grams.
- D. This option is incorrect. This value is the atomic mass of hydrogen in atomic mass units, not the number of molecules.
- E. This option is incorrect. This number could suggest 2 molecules, but the question asks for the total number of molecules in 2 grams of H2.
Q118. What will be the product of the following reaction?
- A. A
- B. B
- C. C
- D. D✓
Explanation: Step 1: Starting compoundWe have p-cresol (4-methylphenol).Step 2: Reaction with CHCl₃/NaOHThis is the Reimer–Tiemann reaction.In this reaction, an aldehyde group –CHO gets introduced at the ortho position to the –OH group.So product A is o-formyl-p-cresol (4-methyl-2-hydroxybenzaldehyde).Step 3: Reaction with HCNAn aldehyde reacts with HCN to give a cyanohydrin.The –CHO group becomes –CH(OH)CN.So compound B is o-(CH(OH)CN)-p-cresol.Step 4: Hydrolysis with H₃O⁺On hydrolysis, –CN group converts to –COOH.So the final product C is o-(CH(OH)COOH)-p-cresol.Step 5: Match with given optionsLooking at the options:(a) has –CH₂COOH (wrong, no hydroxyl group)(b) also has –CH₂COOH (wrong)(c) has –CH(OH)COOH but with two methyls (wrong position)(d) has –CH(OH)COOH correctly at the ortho position to OH, with a para –CH₃ substituent (correct).
Why the other options are wrong
- A. Option A suggests a reaction product that does not involve the correct sequence of reactions or the correct functional group transformations.
- B. Option B presents an incorrect intermediate that might result from a misunderstanding of the nitrile hydrolysis step.
- C. this is not correctThis option shows the correct -CH(OH)COOH group, but the positions of the other groups on the benzene ring are different from the starting material. The reaction does not change the position of the methyl (CH_3) or hydroxyl (OH) groups.
Q119. The product for the given reaction is:
- A. Option A✓
- B. Option B
- C. Option C
- D. Option D
Explanation: Structure: Cyclohexene with a =CH₂ group (i.e., methylene cyclohexane).Explanation:This is the correct product.The –CH₂OH group loses water and forms a double bond at the exocyclic position.This is called an exocyclic alkene (double bond between ring carbon and exo carbon).Matches expected product of alcohol dehydration
Why the other options are wrong
- B. Structure: Cyclohexane (saturated six-membered ring).Explanation:This is fully saturated and has no functional group.Does not match the product of acid-catalyzed alcohol dehydration (which should be an alkene).❌ Incorrect. No elimination took place.
- C. Structure: Cyclohexene (a double bond inside the ring).Explanation:A double bond within the ring suggests a rearranged product.However, in this case, dehydration of –CH₂OH on cyclohexyl does not lead to internal cyclohexene.There's no hydride shift possible to move the carbocation into the ring.❌ Incorrect. Wrong position of double bond.
- D. Structure: Cyclohexene with a CH₃ substituent at exo position.Explanation:This is methylcyclohexene.It suggests that the –CH₂OH group became a methyl group, which is not possible under dehydration.No such methylation occurs in this acid-catalyzed reaction.❌ Incorrect. Does not follow reaction mechanism.
Q120. Which of the following values of heat of formation indicates that the product is least stable?
- A. - 94 kcal
- B. + 21.4 kcal
- C. - 231 kcal
- D. + 64.8 kcal✓
Explanation: In the context of heat of formation (ΔH), a negative value indicates that the formation of the compound is exothermic, meaning the compound is more stable compared to its constituent elements in their standard states.So, the least stable compound among the options provided would have the most positive (ΔH) value and option d has the most positive value ,hence that is the correct option.
Why the other options are wrong
- A. A negative value indicates that the formation of the compound is exothermic, meaning the compound is more stable compared to its constituent elements in their standard states.So, the least stable compound among the options provided would have the most positive (ΔH) value ,hence this option is incorrect.
- B. A negative value indicates that the formation of the compound is exothermic, meaning the compound is more stable compared to its constituent elements in their standard states.So, the least stable compound among the options provided would have the most positive (ΔH) value ,hence this option is not correct as option d)+64.8 has a more positive value.
- C. A negative value indicates that the formation of the compound is exothermic, meaning the compound is more stable compared to its constituent elements in their standard states.So, the least stable compound among the options provided would have the most positive (ΔH) value ,hence this option is incorrect.
Q121. Most abundant salt of sodium in nature is:
- A. NaNO3
- B. Na2SO4
- C. NaOH
- D. NaCl✓
Explanation: The most abundant salt of sodium in nature is sodium chloride (NaCl).The concentration of salt in seawater (its salinity) is about 35 parts per thousand; in other words, about 3.5% of the weight of seawater comes from the dissolved salts.
Why the other options are wrong
- A. NaNO3 is not abundant salt of sodium in nature.
- B. Na2SO4 is not abundant salt of sodium in nature.
- C. NaOH is not abundant salt of sodium in nature.
Q122. What is the volume in cm3 of 3.01 x 10^23 molecules of O2 gas at S.T.P.?
- A. 1000 cm3
- B. 11000 cm3
- C. 1120 cm3
- D. 11200 cm3✓
Explanation: 3.01*10^23 /6.02*10^23 = 0.5 mole at STP,1 mole of gas –––> 22,4 L 0,5 mole –––––––> x x= 11,2 L 11,2 L = 11200 cm3 As this is a numerical, it can only have one correct answer which is option D
Why the other options are wrong
- A. Volume is 11200cm³ not 1000cm³.
- B. Volume is 11200cm³ not 11000cm³.
- C. Volume is 11200cm³ not 1120 cm³.
Q123. In the reaction 2Fe+Cl2 -> 2FeCl3
- A. Fe is reduced
- B. Fe is oxidized✓
- C. Cl2 oxidized
- D. None of the above
Explanation: The Oxidation state of iron(Fe) is changed from "0" to "+3". Hence it is oxidised.
Why the other options are wrong
- A. The Oxidation state of iron(Fe) is changed from "0" to +3. Hence it is oxidised and not reduced.
- C. The Oxidation state of chlorine is reduced from "0" to "-1".
- D. Incorrect option.
Q124. Given the reaction: C3H8 + 5O2 → 3CO2 + 4H2O At STP , how many litres of O2 are needed to completely burn 5.0 litres of C3H8?
- A. 5
- B. 10
- C. 10.5
- D. 15
- E. 25✓
Explanation: Consider that no. of moles of reactants = volume of the reactants.As the molar ratio between C3H6 and O2 is 1:5, the volume ratio is also the same. For 1L of C3H6 we need 5L of O2. Since the volume of C3H6 is 5L now, to burn this, we require 25L of O2.All other options are incorrect because they do not follow the exact mole-volume relationship required in this case.
Why the other options are wrong
Q125. For the reaction: N2 + 3H2 ⇌ 2NH3 .The production of NH3 will be favored at:
- A. High pressure and catalyst✓
- B. Low pressure only
- C. Low pressure and catalyst
- D. High pressure only
- E. Catalyst only
Explanation: The forward reaction forms fewer moles of gas (4 → 2), so high pressure shifts equilibrium toward NH₃. A catalyst increases the reaction rate but does not change equilibrium position. Therefore, maximum ammonia production is achieved using high pressure along with a catalyst.
Why the other options are wrong
- B. To determine the favored conditions, you can apply Le Chatelier's Principle. Increasing pressure favors the side with fewer moles of gas. Since there are fewer moles on the right (2 moles of NH3) compared to the left (4 moles of N2 and 6 moles of H2), higher pressure would favor the production of NH3. There this option is not correct.
- C. To determine the favored conditions, you can apply Le Chatelier's Principle. Increasing pressure favors the side with fewer moles of gas. Since there are fewer moles on the right (2 moles of NH3) compared to the left (4 moles of N2 and 6 moles of H2), higher pressure would favor the production of NH3. Therefore this option is not correct.
- D. To determine the favored conditions, you can apply Le Chatelier's Principle. Increasing pressure favors the side with fewer moles of gas. Since there are fewer moles on the right (2 moles of NH3) compared to the left (4 moles of N2 and 6 moles of H2), higher pressure would favor the production of NH3.
- E. To determine the favored conditions, you can apply Le Chatelier's Principle. Increasing pressure favors the side with fewer moles of gas. Since there are fewer moles on the right (2 moles of NH3) compared to the left (4 moles of N2 and 6 moles of H2), higher pressure would favor the production of NH3. Therefore this option is not correct.
Q126. Catenation is a process in which carbon shows the properties of:
- A. Making single bond
- B. Hybridization
- C. Making chains or rings of carbon atoms✓
- D. Isomerism
- E. Breaking of bonds
Explanation: Catenation is the process by which an atom is able to form a bond with another atom of its kind. Carbon possesses this ability hence is able to form ringed structures.
Why the other options are wrong
- A. Catenation is the process by which an atom is able to form a bond with another atom of its kind. Carbon possesses this ability hence is able to form ringed structures.Option A is incorrect as catenation is the property of forming all kinds of bonds with the same kind of atoms either single, double or triple.
- B. Option B is incorrect as hybridization is the process in which atomic orbitals mix to form new hybrid orbitals suitable for the pairing of electrons to form chemical bonds.
- D. Option D is incorrect as isomerism is the phenomena exhibited by organic compounds in which compounds have the same molecular formula but different structural formula.
- E. Option E is incorrect as catenation does not involve breaking of bonds.
Q127. The maximum number of electrons that an orbital can accommodate is/are:
- A. 0
- B. 1
- C. 2✓
- D. 3
- E. 4
Explanation: The maximum number of electrons in a single orbital is two. The maximum number of electrons an orbital can accommodate is 2. As in an orbital two electrons can never have the same values of all 4 quantum no.s according to Pauli’s exclusion principle. So to follow this rule, an orbital can accommodate 2 electrons only.
Why the other options are wrong
- A. Option A is wrong as this is not the maximum amount of electrons that an orbital can accomadate.
- B. Option B is wrong as this is not the maximum amount of electrons that an orbital can accomadate.
- D. Option D is wrong as the number of electrons are beyond that an orbital can accomadate.
- E. Option E is wrong as the number of electrons are beyond that an orbital can accomadate.
Q128. The general formula for an aldehyde is:
- A. R-OH
- B. R-COOH
- C. R-CO-R
- D. R-X
- E. R-CHO✓
Explanation: Aldehydes and ketones have a carbonyl group (C=O) as a functional group. A ketone has two alkyl or aryl groups attached to the carbonyl carbon (RCOR’). The simplest ketone is acetone, which has two methyl groups attached to the carbonyl carbon (CH3COCH3).An aldehyde is similar to a ketone, except that instead of two side groups connected to the carbonyl carbon, they have at least one hydrogen (RCOH or R-CHO). The simplest aldehyde is formaldehyde (HCOH), as it has two hydrogens connected to the carbonyl group. All other aldehydes have one hydrogen bonded to the carbonyl group, like the simple molecule acetaldehyde, which has one hydrogen and one methyl group (HCOCH3).The carbonyl carbon in both aldehydes and ketones is electrophilic, meaning that it has a dipole due to the electronegativity of the attached oxygen atom. This makes the carbonyl carbon an ideal target for nucleophiles in a nucleophilic addition reaction. During this reaction, the nucleophile, or electron donor, attacks the carbonyl to form the tetrahedral intermediate. The negatively charged oxygen accepts a hydrogen ion to form a hydroxyl group.Typically, nucleophiles possess a negative charge or lone pair on a heteroatom, which can take several forms (OH-, RO-, CN-, R3C-, RNH2, ROH). For primary amines (RNH2), the reaction does not stop at the formation of the tetrahedral intermediate with a hydroxyl group. Rather, an elimination reaction occurs that produces a double-bonded carbon and nitrogen functional group known as an imine. Understanding the reactions that aldehydes and ketones can undergo provides a way to differentiate between these similar organic compounds.
Why the other options are wrong
- A. Option A is wrong as R-OH is the general formula of alcohol.
- B. Option B is wrong R-COOH is the general formula of carboxylic acid.
- C. Option C is wrong as R-CO-R is the general formula of ketone.
- D. Option D is wrong as R-X is the general formula of alkyl halides.
Q129. When an element exists in more than one crystalline form, the phenomenon is termed as:
- A. Isomorphism
- B. Allotropy✓
- C. Isomerism
- D. Anisotropy
- E. Enthalpy
Explanation: Allotropy is the correct answer because it describes the ability of an element to exist in multiple forms or structures in the same physical state, such as carbon which can be found as diamond, graphite, and graphene.Isomorphism is incorrect as it refers to different substances with the same crystal structure. Isomerism is about different structural arrangements in organic compounds, not crystalline forms. Anisotropy deals with directional properties and not multiple forms of an element. Enthalpy involves thermodynamic measurements, not crystalline structures.
Why the other options are wrong
- A. Isomorphism refers to the phenomenon where different compounds have the same crystal structure. It is not about a single element existing in different forms.
- C. Isomerism involves compounds having the same molecular formula but different structural arrangements, typically not related to crystalline forms.
- D. Anisotropy refers to the directional dependence of properties in a material, not to elements existing in different forms.
- E. Enthalpy is the measure of total heat content in a thermodynamic system, unrelated to crystalline forms of an element.
Q130. Which of the following statements about H2S is false:
- A. It is a covalent compound
- B. It is a gas with a bad smell
- C. It is a strong reducing agent
- D. It is a molecule which is non linear
- E. It is a weak base in water✓
Explanation: H2S is a weak acid, donating two hydrogen ions in neutralization reactions, forming HS- and S-2 ions, not a weak base. Hence option E is the correct answer.H2S is a covalent compound with a rotten egg smell. It is a strong reducing agent with a bent (non-linear) geometry.
Why the other options are wrong
- A. Option A is wrong as H2S is a covalent compound.
- B. Option B is wrong as H2S has a rotten egg smell which is pungent.
- C. Option C is wrong as it is a strong reducing agent.
- D. Option D is wrong as H2S has a bent (non- linear) geometry.
Q131. When 18 ×10-3 moles/dm3 of acetic acid react with 22×10-3 moles/dm3 of ethyl alcohol to form 40×10-3 moles/dm3 of ethyl acetate and 40×10-3 moles/dm3 of waterFind the value of equilibrium constant (Kc)
- A. 4.04✓
- B. 3.14
- C. 3.04
- D. 2.02
- E. 1.04
Explanation: Kc= Concentration of products / Concentration of Reactants. Reactants = acetic acid and ethyl alcohol Products = ethyl acetate and water Multiplication product of products (40 × 40 =1600) Divide by multiplication product of reactants (18× 22= 396) 1600/396= 4.04.
Why the other options are wrong
- B. This option is incorrect. Kc= Concentration of products / Concentration of Reactants.Reactants = acetic acid and ethyl alcoholProducts = ethyl acetate and waterMultiplication product of products (40 × 40 =1600)Divide by multiplication product of reactants(18× 22= 396)1600/396= 4.04.
- C. This option is incorrect. Kc= Concentration of products / Concentration of Reactants.Reactants = acetic acid and ethyl alcoholProducts = ethyl acetate and waterMultiplication product of products (40 × 40 =1600)Divide by multiplication product of reactants(18× 22= 396)1600/396= 4.04.
- D. This option is incorrect. Kc= Concentration of products / Concentration of Reactants.Reactants = acetic acid and ethyl alcoholProducts = ethyl acetate and waterMultiplication product of products (40 × 40 =1600)Divide by multiplication product of reactants(18× 22= 396)1600/396= 4.04.
- E. This option is incorrect. Kc= Concentration of products / Concentration of Reactants.Reactants = acetic acid and ethyl alcoholProducts = ethyl acetate and waterMultiplication product of products (40 × 40 =1600)Divide by multiplication product of reactants(18× 22= 396)1600/396= 4.04.
Q132. Sigma bond is formed by:
- A. Transferring the electrons
- B. Head-on overlapping of atomic orbitals✓
- C. Mutual but unequal sharing of electrons
- D. Parallel overlapping of atomic orbitals
- E. All of these options
Explanation: The sigma bond, the strongest type of covalent bond, is formed by the head-on overlapping of atomic orbitals. This overlap allows for maximum electron density between the two bonding nuclei, resulting in a stable bond. In contrast, ionic bonds are formed by the transfer of electrons (Option A), polar covalent bonds arise from mutual but unequal sharing of electrons (Option C), and pi bonds result from the parallel overlapping of atomic orbitals (Option D). Thus, Option B is the only correct description for sigma bond formation.
Why the other options are wrong
- A. Option A is incorrect because the transfer of electrons leads to the formation of ionic bonds, not sigma bonds.
- C. Option C is incorrect because mutual but unequal sharing of electrons results in a polar covalent bond, not a sigma bond.
- D. Option D is incorrect because parallel overlapping of atomic orbitals results in the formation of pi bonds, not sigma bonds.
- E. Option E is incorrect since only option B describes the correct process for forming sigma bonds.
Q133. The unit of viscosity is:
- A. Joule
- B. N/m2
- C. Dynes/cm
- D. Poise✓
- E. Ergs
Explanation: The cgs unit of viscosity is poise (P) whereas the SI unit of viscosity is newton-second per square meter, which is usually expressed as pascal-second.
Why the other options are wrong
- A. Joule is a unit of energy or work, not viscosity. It measures the amount of work done when a force is applied over a distance.
- B. N/m2, or pascal (Pa), is a unit of pressure, not viscosity. It represents force per unit area.
- C. Dynes per centimeter is a unit of surface tension, not viscosity. It measures force along a line of unit length.
- E. The erg is a unit of energy in the cgs system, not viscosity. It is a small unit of work or energy.
Q134. The maximum possible number of electrons a shell 'n' can accommodate is given by:
- A. n
- B. n2
- C. 2n2✓
- D. n3
- E. 3n2
Explanation: The maximum number of electrons that can be in a shell is 2n2.
Why the other options are wrong
- A. The principal quantum number 'n' indicates the energy level of an electron shell but does not determine its electron capacity directly.
- B. The formula n² gives the total number of orbitals in a shell but not the maximum number of electrons it can hold.
- D. n³ is not a recognized formula in atomic theory for calculating electron capacity or orbital count.
- E. 3n² is not a valid formula for determining electron capacity in atomic structure.
Q135. Cl + e ----> Cl-ΔH = -348kJ/molThe value -348KJ/mol in this case will be:
- A. Ionization energy
- B. Electronegativity
- C. Electron affinity✓
- D. Entropy
- E. Free energy
Explanation: As it can be seen in the equation, electrons are gained by the element chlorine to form a negative ion (anion). The process in which electrons are gained is called electron affinity.
Why the other options are wrong
- A. Ionization energy is the energy required to remove an electron from a gaseous atom. Here, an electron is being added, not removed.
- B. Electronegativity refers to an atom's ability to attract shared electrons in a bond. This process does not involve forming a bond, but rather adding an electron to form an ion.
- D. Entropy measures the disorder or randomness in a system. It does not directly relate to the energy change associated with adding an electron to an atom.
- E. Gibbs free energy measures the maximum reversible work done by a thermodynamic system at constant temperature and pressure. It is not specifically about adding an electron to an atom.
Q136. Which of the following is an instrument for monitoring radiations:
- A. GM tube
- B. Radar
- C. Wilson cloud chamber
- D. Both A and C✓
Explanation: The Geiger-Mueller (GM) detector is a common portable instrument choice for a general laboratory radioactive material survey. GM detectors are capable of detecting alpha, beta, and gamma radiation. However, this instrument is limited by its ineffectiveness in detecting lower energy beta and gamma emitters.Radars send out electromagnetic waves as short pulses which may be reflected by objects in their path, in part reflecting to the radar. When these pulses intercept precipitation, part of the energy is scattered back to the radar.A cloud chamber, also known as a Wilson cloud chamber, is a particle detector used for visualizing the passage of ionizing radiation.
Why the other options are wrong
- A. The Geiger Mueller (GM) detector is a common portable instrument choice for a general laboratory radioactive material survey. GM detectors are capable of detecting alpha, beta, and gamma radiation. However, this instrument is limited by its ineffectiveness in detecting lower energy beta and gamma emitters. Geiger counter is also called a Geiger tube. This instrument is used for detecting and measuring ionizing radiation like alpha particles, beta particles, and gamma rays. A Geiger-Müller counter can count individual particles at rates up to about 10,000 per second and is used widely in medicine and prospecting for radioactive ores.
- B. Radars send out electromagnetic waves as short pulses which may be reflected by objects in their path, in part reflecting back to the radar. When these pulses intercept precipitation, part of the energy is scattered back to the radar. It is an electromagnetic sensor used for detecting, locating, tracking, and recognizing objects of various kinds at considerable distances. It operates by transmitting electromagnetic energy toward objects, commonly referred to as targets, and observing the echoes returned from them.
- C. A cloud chamber, also known as a Wilson cloud chamber, is a particle detector used for visualizing the passage of ionizing radiation.
Q137. The half-life of a radioactive element depends upon:
- A. Amount of element present
- B. Pressure
- C. Temperature
- D. None of the above options are correct✓
Explanation: The correct answer is Option D. The half-life of a radioactive element is a fundamental property of that element, determined by the stability of its nucleus, and does not change with external factors like the amount of element present, temperature, or pressure. Options A, B, and C are incorrect because they suggest that half-life could be influenced by these external conditions, which it is not.
Why the other options are wrong
- A. It does not depend on the temperature, concentration, or the amount of element and pressure, but just depends on the time factor.Hence, this is an incorrect option.
- B. It does not depend on the temperature, concentration, or the amount of element and pressure, but just depends on the time factor.Hence, this is an incorrect option.
- C. It does not depend on the temperature, concentration, or the amount of element and pressure, but just depends on the time factor.Hence, this is an incorrect option.
Q138. Radiation can cause:
- A. leukemia
- B. radiation sickness
- C. skin cancer
- D. gene mutations
- E. all of the above✓
Explanation: Radiation can lead to multiple adverse health effects, including leukemia, radiation sickness, skin cancer, and gene mutations. Each of these outcomes stems from the ability of radiation to damage biological tissues and DNA. Leukemia is linked to radiation's impact on bone marrow, radiation sickness results from acute high-level exposure, skin cancer is associated with UV radiation, and gene mutations can occur due to ionizing radiation disrupting DNA. Therefore, the most comprehensive answer is all of the above, as radiation can indeed cause all these effects.
Why the other options are wrong
- A. Radiation exposure is a known risk factor for the development of leukemia. The bone marrow is highly sensitive to radiation, which can disrupt the normal production of blood cells and lead to this type of cancer.
- B. Radiation sickness or acute radiation syndrome results from a high dose of radiation over a short period, leading to symptoms such as nausea, vomiting, and potential organ damage.
- C. Long-term exposure to ionizing radiation, especially UV radiation, can damage skin cell DNA, increasing the risk of skin cancer.
- D. Ionizing radiation can directly damage DNA, causing mutations that may lead to various health issues, including cancer. These mutations can also be inherited if they occur in germ cells.
Q139. The shortest wavelength photon emitted in the Balmer series is:
- A. 1.0974 nm
- B. 4 nm
- C. 364.6 nm✓
- D. 3.64 m
- E. 480 nm
Explanation: Attached below is the solution to the question above:
Why the other options are wrong
- A. This option confuses the Rydberg constant (R = 1.0974 x 107 m-1) with the wavelength. The shortest wavelength for the Balmer series is 364.6 nm, not 1.0974 nm.
- B. This value is incorrect because it is much smaller than the actual shortest wavelength in the Balmer series, which is 364.6 nm.
- D. This option incorrectly suggests a wavelength in meters. The correct shortest wavelength in the Balmer series is 364.6 nm, not 3.64 m.
- E. This option provides a wavelength longer than the correct shortest wavelength in the Balmer series, which is 364.6 nm.
Q140. One complete circle is equal to:
- A. 2π radian✓
- B. 3 radian
- C. 5 radian
- D. 9 radian
Explanation: There are 2π radians in a full circle. So 2π radians should equal 360°.
Why the other options are wrong
- B. The angular displacement of one complete circle is equal to 2π radian. 2x3.14=6.28 radian which can be approximated to 6 radian.
- C. The angular displacement of one complete circle is equal to 2π radian. 2x3.14=6.28 radian which can be approximated to 6 radian.
- D. The angular displacement of one complete circle is equal to 2π radian. 2x3.14=6.28 radian which can be approximated to 6 radian.
Q141. The frequency of a man's voice is 300 Hz. If velocity of sound is 336 m/s, the wavelength of the sound is:
- A. 1.12 m✓
- B. 300 m
- C. 330 m
- D. 112 m
- E. 11201 m
Explanation: We are given thatfrequency=300Hz, and velocity v=336ms−1From the relation v=f×λ,λ=v/f=336/300=1.12mOption "A" is correct.
Why the other options are wrong
- B. This option is incorrect. This value seems to incorrectly consider the velocity of sound as the wavelength without using the formula λ = v/f.
- C. This option is incorrect. It may have been calculated by mistakenly using the frequency as the wavelength instead of applying the correct formula.
- D. This option is incorrect, possibly due to a miscalculation or misplacement of the decimal point when using the formula λ = v/f.
- E. This option is incorrect and is likely an error due to a significant miscalculation or misplacement of the decimal point.
Q142. The physical quantity which produces angular acceleration in the body is
- A. Force
- B. Moment of inertia
- C. Impulse
- D. Torque✓
Explanation: Torque is a measure of the force that can cause an object to rotate about an axis. Just as force is what causes an object to accelerate in linear kinematics, torque is what causes an object to acquire angular acceleration
Why the other options are wrong
- A. Force is responsible for translational motion of a body.
- B. Moment of inertia is the rotational analogue of mass. It plays the same role as mass in translational motion.
- C. Impulse is the rate of change of momentum of a body.
Q143. A jeep travelling at a constant speed of 108 km/hr rounds a curve of radius 100 m. Find its acceleration.
- A. 3 m/s2
- B. 6 m/s2
- C. 7 m/s2
- D. 8 m/s2
- E. 9 m/s2✓
Explanation: The correct answer is 9 m/s2. To find the acceleration of the jeep as it rounds the curve, we use the formula for centripetal acceleration: a = v2 / r, where 'v' is the velocity and 'r' is the radius of the curve. The velocity is given as 108 km/hr, which must be converted to meters per second by dividing by 3.6, resulting in 30 m/s. Substituting into the formula: a = (30 m/s)2 / 100 m = 9 m/s2. The other options are incorrect because they arise from either incorrect unit conversion or misapplication of the centripetal acceleration formula.
Why the other options are wrong
- A. This is incorrect. Double-check the formula for centripetal acceleration and ensure that the units are converted correctly.
- B. This is incorrect. Revisit the conversion from km/hr to m/s and the calculation of centripetal acceleration.
- C. This is incorrect. Ensure that the formula for centripetal acceleration is applied correctly with the proper units.
- D. This is incorrect. Verify your calculation steps to ensure the correct application of the centripetal acceleration formula.
Q144. In what form is the energy stored in a charged capacitor?
- A. Gravitational
- B. Electrical potential✓
- C. Magnetic field
- D. Potential
Explanation: Energy is stored in a form of electrostatic field between plates of capacitor. This energy can be expressed in the form of work done by the battery.
Why the other options are wrong
- A. Energy stored in a charged capacitor is not in the form of gravitational energy. Gravitational energy is associated with the gravitational field and the position of objects relative to each other in a gravitational field, whereas a capacitor stores energy in an electric field.
- C. Energy stored in a charged capacitor is not in the form of a magnetic field. Capacitors primarily store energy in an electric field between their plates. While there might be small induced magnetic fields around the conductors carrying current during charging and discharging processes, the predominant energy storage mechanism in a capacitor is electric, not
- D. This option is somewhat related to option b). The energy stored in a capacitor is indeed related to potential, specifically electrical potential or voltage. The potential difference between the plates of the capacitor, caused by the accumulation of charges on the plates, represents the stored energy.
Q145. A body moves on a circular path subtending an angle of 2 radians at the center of a circle of radius 3.5 meters. The linear displacement of the body is _.
- A. 6.5 m
- B. 7 m✓
- C. 7.5 m
- D. 1.75 m
Explanation: The linear displacement of a body moving along a circular path can be determined using the formula:Linear Displacement = 2 × Radius × sin(θ/2)Here, the radius (r) is 3.5 meters, and the angle (θ) is 2 radians. Plugging in the values, we apply:Linear Displacement = 2 × 3.5 × sin(2/2) = 2 × 3.5 × sin(1) ≈ 7 metersTherefore, the correct linear displacement of the body is 7 meters. All other options (6.5 m, 5.8 m, 7.5 m, and 1.75 m) do not match the computed value from the provided formula and parameters.
Why the other options are wrong
- A. This option is incorrect because it does not accurately apply the formula for linear displacement.
- C. This option is incorrect because it overestimates the linear displacement based on the given parameters.
- D. This option is incorrect as it significantly underestimates the linear displacement derived from the radius and angle.
Q146. A car starts from rest and moves with a constant acceleration. During the 5th second of its motion, it covers a distance of 36 meters. What is the acceleration of the car?
- A. 12.5 m/s2
- B. 8 m/s2✓
- C. 15 m/s2
- D. 16 m/s2
- E. 14 m/s2
- F. 2.88 m/s2
Explanation: You will find the distance traveled in 5 and 4 seconds individually. After subtracting these two terms and equating it to 36 meters, all variables are fulfilled other than a which we can solve for.In the below equations, s is distance, a is acceleration, and t is time.In 4 seconds, the truck covers:s = 1/2 at2s = 1/2 (a) 42s = 1/2 (a) (16)s = 8 (a) metersIn 5 seconds, the truck coverss = 1/2 a t2s = 1/2 (a) 52s = 1/2 (a) 25s = 12.5 (a) metersThe distance covered in 5 seconds minus the distance covered in 4 seconds is the distance (36 meters) covered in the 5th second.36 = 12.5 a - 8 a36 meters = 4.5 seconds2 (a)a = acceleration = 8 m/s2
Why the other options are wrong
- A. This value is incorrect. It results from incorrect calculations or assumptions about the time and distance relationship under constant acceleration.
- C. This value is too high, which means the calculated acceleration is overestimated. Check the calculations for any arithmetic mistakes.
- D. This value is double the correct answer, indicating a misunderstanding of the motion equations or a calculation error.
- E. This is an overestimate. The calculations need to be revisited to ensure the correct use of formulas.
- F. This value is too low, suggesting an error in applying the kinematic equations or misinterpretation of the data.
Q147. Projectile must be launched at which angle with the horizontal to attain maximum range?
- A. 90 degrees
- B. 45 degrees✓
- C. 75 degrees
- D. 105 degrees
- E. 145 degrees
Explanation: To achieve maximum range, a projectile should be launched at an angle of 45 degrees with the horizontal. This angle provides the ideal balance between vertical and horizontal components of velocity, maximizing the distance traveled horizontally. The formula R = (v^2 sin2θ)/g confirms that maximum range occurs when sin2θ equals 1, which happens at θ = 45 degrees. Other angles, such as 90 degrees, result in no horizontal range, while angles greater than or less than 45 degrees reduce the range due to an imbalance in velocity components.
Why the other options are wrong
- A. Incorrect. At 90 degrees, the projectile goes straight up and comes straight down, resulting in zero horizontal range. The formula R = (v2 sin2θ)/g shows that sin2θ is zero when θ = 90 degrees.
- C. Incorrect. At 75 degrees, the projectile has a higher vertical component of velocity, leading to a higher peak but a shorter range than at 45 degrees. The maximum range is achieved at 45 degrees.
- D. Incorrect. Angles greater than 90 degrees imply the projectile is launched back towards the launch point with a reduced range. The optimal angle for maximum range is 45 degrees.
- E. Incorrect. This angle results in a negative horizontal component of velocity, reducing the range significantly. The maximum range is achieved at 45 degrees.
Q148. Law of conservation of momentum states that:I. there is no external force applied to a system, then the total momentum of that system remains constant II. if there is an external force applied to a system, then the total momentum of that system remains constant III. if there is no external force applied to a system, then the total momentum of that system keeps changing
- A. I only✓
- B. I and II only
- C. I and III only
- D. III only
- E. I, II and III
Explanation: If there is no external force applied to the system, then the total momentum of that system remains constant. If an external force is applied then the total momentum will change.The law of conservation of momentum states that, for two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed and will stay constant.
Why the other options are wrong
- B. Wrong answer. Law of conservation of momentum states that. For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.
- C. Wrong answer. Law of conservation of momentum states that. For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.
- D. Wrong answer. Law of conservation of momentum states that. For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.
- E. Wrong answer. Law of conservation of momentum states that. For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.
Q149. The half-life of C14 is about:
- A. 1637 years
- B. 892 years
- C. 10 years
- D. 100 years
- E. 5730 years✓
Explanation: Carbon-14 has a half-life of 5,730 ± 40 years—i.e. half the amount of the radioisotope present at any given time will undergo spontaneous disintegration during the succeeding 5,730 years.
Why the other options are wrong
- A. This is incorrect. 1637 years is not a recognized half-life for carbon-14 or any common isotope used in dating.
- B. This is incorrect. 892 years is not associated with the half-life of carbon-14.
- C. This is incorrect. 10 years is far too short for the half-life of carbon-14, which is used in dating ancient artifacts.
- D. This is incorrect. 100 years is not the half-life of carbon-14 and is not suitable for radiocarbon dating's time scale.
Q150. Sodium nucleus consists of 11 protons and 12 neutrons. The conventional symbol of this nucleus is?
- A. 11Na11
- B. 12Na12
- C. 11Na23✓
- D. 12Na23
- E. 12Na11
Explanation: The conventional symbol of the element contains the proton number(number of protons) and the mass number(proton number+number of neutrons), which is 11 and (11+12=)23, in this case. So the correct option is C. The conventional symbol of a sodium nucleus is 11Na23.
Why the other options are wrong
- A. As per the explanation, this option is incorrect.
- B. As per the explanation, this option is incorrect.
- D. As per the explanation, this option is incorrect.
- E. As per the explanation, this option is incorrect.
Q151. The process of natural decay of some heavy nuclides is because of the phenomenon:
- A. Emission Spectra
- B. Nuclear fusion
- C. Nuclear fission
- D. Radioactivity✓
Explanation: Radioactivity is the spontaneous emission of radiation in the form of particles or high-energy photons resulting from a nuclear reaction. It is also known as radioactive decay, nuclear decay, nuclear disintegration, or radioactive disintegration. Alpha, beta, and gamma decay are three common radioactivity processes
Why the other options are wrong
- A. Emission Spectra : The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an electron making a transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states.
- B. Nuclear fusion :Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles. The difference in mass between the reactants and products is manifested as either the release or absorption of energy.
- C. Nuclear fission: Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay.
Q152. The deviation of I-V graph from straight line is due to:
- A. Decrease in temperature and decrease in resistance
- B. Increase in temperature and increase in resistance✓
- C. Decrease in temperature and increase in resistance
- D. Increase in temperature and decrease in resistance
Explanation: The most common scenario leading to a deviation from a straight-line I-V graph is an increase in temperature and an increase in resistance. This is often observed in conductors and is known as a positive temperature coefficient of resistance. As temperature rises, the resistance increases, causing a departure from the ideal linear behavior in the I-V graph.
Why the other options are wrong
- A. If temperature decreases and resistance also decreases, it is less likely to cause a significant deviation from a straight-line I-V graph. Typically, resistance tends to increase with decreasing temperature.
- C. This combination is common in many materials. As temperature decreases, the resistance often increases. The increase in resistance can contribute to a deviation from the straight-line behavior in the I-V graph.
- D. This combination is less common for typical conductors. In most materials, as temperature increases, resistance also increases. However, certain materials like semiconductors may exhibit a decrease in resistance with increasing temperature under specific conditions.
Q153. A battery whose emf is 40 V has an internal resistance of 5 Ohms. If this battery is connected to a 15 Ohms resistor ‘R’, what will be the voltage drop across ‘R’:
- A. 10 V
- B. 30 V✓
- C. 40 V
- D. 50 V
- E. 70 V
Explanation: 40 = I x (15+ 5) 40= I x 20 I = 40/20 I= 2 AVoltage drop across resistor R V= IR V= 2 x 15 V= 30 V (hence B is the correct option)
Why the other options are wrong
- A. According to given data, this option is incorrect as explained below. Total voltage= current x total resistance 40 = I x (15+ 5) 40= I x 20 I = 40/20 I= 2 AVoltage drop across resistor R V= IRV= 2 x 15 V= 30 V (hence B is the correct option)
- C. According to given data, this option is incorrect as explained below. Total voltage= current x total resistance 40 = I x (15+ 5) 40= I x 20 I = 40/20 I= 2 AVoltage drop across resistor R V= IRV= 2 x 15 V= 30 V (hence B is the correct option)
- D. According to given data, this option is incorrect as explained below. Total voltage= current x total resistance 40 = I x (15+ 5) 40= I x 20 I = 40/20 I= 2 AVoltage drop across resistor R V= IRV= 2 x 15 V= 30 V (hence B is the correct option)
- E. According to given data, this option is incorrect as explained below. Total voltage= current x total resistance 40 = I x (15+ 5) 40= I x 20 I = 40/20 I= 2 AVoltage drop across resistor R V= IRV= 2 x 15 V= 30 V (hence B is the correct option)
Q154. What is the flux density at a point 3 cm from the current carrying conductor, when there is a current of 25 A in a wire: (u0= 4𝜋 x10-7)
- A. 0.23x10-1T
- B. 1.67x 10-4T✓
- C. 2.99x10-6T
- D. 3.63x10-8T
- E. 999x10-7T
Explanation: The correct answer is 1.67x10-4T. To find the magnetic flux density (B) at a distance (r) from a long straight wire carrying current (I), you can use the formula:B = (μ0 * I) / (2 * π * r).Substituting in the values: μ0 = 4π x 10-7 T·m/A, I = 25 A, and r = 0.03 m (3 cm), we get:B = (4π x 10-7 * 25) / (2 * π * 0.03) = 1.67 x 10-4T.Other options are incorrect because:0.23x10-1T is too high, not matching the expected results.2.99x10-6T is too low compared to the calculations.3.63x10-8T is orders of magnitude smaller than expected.999x10-7T converts to an unreasonably high value of 0.0999 T.
Why the other options are wrong
- A. This option suggests a magnetic flux density that is too high based on the provided current and distance. It does not reflect the calculations derived from the magnetic field formula.
- C. This value is significantly lower than what is expected from the calculations. It does not align with the magnetic flux density that should be derived from the given parameters.
- D. This option is incorrect as it indicates a magnetic flux density that is far too low based on the calculations using the given current and distance.
- E. This option misleadingly converts to 0.0999 T, which is excessively high compared to the expected magnetic flux density in this context.
Q155. A battery has an e.m.f of 6.0 volts and an internal resistance of 0.4 ohms. It is connected to a 2.6 ohms resistor through a SPST (single pole, single throw switch). When the switch is open, the potential difference between the terminal of the battery is:
- A. 0 V
- B. 0.8 V
- C. 2.6 V
- D. 5.2 V
- E. 6.0 V✓
Explanation: The emf of a battery is generated by the chemical action in the battery. When no current is being drawn from the battery, the difference in potential between the terminals is equal to the emf.
Why the other options are wrong
- A. This is incorrect according to the explanation.The emf of a battery is generated by the chemical action in the battery. As the switch is open no current is being drawn from the battery, hence the difference in potential between the terminals is equal to the emf that is 6.0 V.
- B. This is incorrect according to the explanation.The emf of a battery is generated by the chemical action in the battery. As the switch is open no current is being drawn from the battery, hence the difference in potential between the terminals is equal to the emf that is 6.0 V.
- C. This is incorrect according to the explanation.The emf of a battery is generated by the chemical action in the battery. As the switch is open no current is being drawn from the battery, hence the difference in potential between the terminals is equal to the emf that is 6.0 V.
- D. This is incorrect according to the explanation.The emf of a battery is generated by the chemical action in the battery. As the switch is open no current is being drawn from the battery, hence the difference in potential between the terminals is equal to the emf that is 6.0 V.
Q156. A coil of 600 turns is threaded by a flux of 8x10-5 webers if this flux is reduced to 3x10-5 webers in 0.015 seconds. The average induced e.m.f. is:
- A. -2.0 volts
- B. -3.0 volts
- C. +2.0 volts✓
- D. +2.5 volts
- E. +3.0 volts
Explanation: Emf = - N (dФ/dt)where number of turns are denoted by N, dФ is the change in flux and dt is the time interval.Change in flux = Final Flux - Initial FluxChange in flux = (3 × 10⁻⁵) - (8 × 10⁻⁵) WbChange in flux = - (5 × 10⁻⁵) Wbtime interval = 0.015 sectime interval = 15 × 10⁻³ secNumber of turns in coil = 600Putting all the values in formula.Emf = - 600 × (-(5 × 10⁻⁵)/15 × 10⁻³) VoltsEmf = 600 × (5 × 10⁻²/15 ) VoltsEmf = 600 × (10⁻²/3 ) VoltsEmf = 200 × 10⁻² VoltsEmf = 2 Volts
Why the other options are wrong
- A. As per explanation, this is incorrect.Emf = - N (dФ/dt)where number of turns are denoted by N, dФ is the change in flux and dt is the time interval.Change in flux = Final Flux - Initial FluxChange in flux = (3 × 10⁻⁵) - (8 × 10⁻⁵) WbChange in flux = - (5 × 10⁻⁵) Wbtime interval = 0.015 sectime interval = 15 × 10⁻³ secNumber of turns in coil = 600Putting all the values in formula.Emf = - 600 × (-(5 × 10⁻⁵)/15 × 10⁻³) VoltsEmf = 600 × (5 × 10⁻²/15 ) VoltsEmf = 600 × (10⁻²/3 ) VoltsEmf = 200 × 10⁻² VoltsEmf = 2 Volts
- B. As per explanation, this is incorrect.Emf = - N (dФ/dt)where number of turns are denoted by N, dФ is the change in flux and dt is the time interval.Change in flux = Final Flux - Initial FluxChange in flux = (3 × 10⁻⁵) - (8 × 10⁻⁵) WbChange in flux = - (5 × 10⁻⁵) Wbtime interval = 0.015 sectime interval = 15 × 10⁻³ secNumber of turns in coil = 600Putting all the values in formula.Emf = - 600 × (-(5 × 10⁻⁵)/15 × 10⁻³) VoltsEmf = 600 × (5 × 10⁻²/15 ) VoltsEmf = 600 × (10⁻²/3 ) VoltsEmf = 200 × 10⁻² VoltsEmf = 2 Volts
- D. Emf = - N (dФ/dt)where number of turns are denoted by N, dФ is the change in flux and dt is the time interval.Change in flux = Final Flux - Initial FluxChange in flux = (3 × 10⁻⁵) - (8 × 10⁻⁵) WbChange in flux = - (5 × 10⁻⁵) Wbtime interval = 0.015 sectime interval = 15 × 10⁻³ secNumber of turns in coil = 600Putting all the values in formula.Emf = - 600 × (-(5 × 10⁻⁵)/15 × 10⁻³) VoltsEmf = 600 × (5 × 10⁻²/15 ) VoltsEmf = 600 × (10⁻²/3 ) VoltsEmf = 200 × 10⁻² VoltsEmf = 2 Volts
- E. As per explanation, this is incorrect.Emf = - N (dФ/dt)where number of turns are denoted by N, dФ is the change in flux and dt is the time interval.Change in flux = Final Flux - Initial FluxChange in flux = (3 × 10⁻⁵) - (8 × 10⁻⁵) WbChange in flux = - (5 × 10⁻⁵) Wbtime interval = 0.015 sectime interval = 15 × 10⁻³ secNumber of turns in coil = 600Putting all the values in formula.Emf = - 600 × (-(5 × 10⁻⁵)/15 × 10⁻³) VoltsEmf = 600 × (5 × 10⁻²/15 ) VoltsEmf = 600 × (10⁻²/3 ) VoltsEmf = 200 × 10⁻² VoltsEmf = 2 Volts
Q157. A semiconductor photodiode is a:
- A. reverse biased junction diode✓
- B. forward biased junction diode
- C. half wave rectifier
- D. full wave rectifier
- E. Transistor
Explanation: The photodiode is reverse biased for operating in the photoconductive mode. As the photodiode is in reverse bias the width of the depletion layer increases. This reduces the junction capacitance and thereby the response time. In effect, the reverse bias causes faster response times for the photodiode.
Why the other options are wrong
- B. A forward biased junction diode is a semiconductor diode that has its p-side connected to the positive terminal of a battery and its n-side connected to the negative terminal. This allows current to flow continuously in one direction.
- C. A half-wave rectifier is a circuit that converts alternating current (AC) to direct current (DC) by only allowing one half of the AC waveform to pass through.
- D. A full wave rectifier is defined as a rectifier that converts the complete cycle of alternating current into pulsating DC.
- E. A transistor is a semiconductor device that controls and amplifies electrical signals. Transistors are a fundamental component of modern electronics.
Q158. A circuit in which there is a current of 5 amp is changed so that the current falls to zero in 0.1s. If an average e.m.f of 200 volts is induced, what is the self-inductance of the circuit?
- A. 4 henrys✓
- B. 8 henrys
- C. 12 henrys
- D. 16 henrys
- E. 20 henrys
Explanation: Initial currect= I1 = 5.0 A Final current= I2= 0 A change in current , dI= I1 -I2 =5A Time taken for the change= 0.1s Avg emf= 200V e=L di/dt L= e /di/dt 200/5/01 = 4H Hence the self inductance of the coil is 4H.
Why the other options are wrong
- B. As per the calculation, this option is incorrect.
- C. As per the calculation, this option is incorrect.
- D. As per the calculation, this option is incorrect.
- E. As per the calculation, this option is incorrect.
Q159. The atomic spectra deals with the measurement of:
- A. Wavelengths
- B. Intensities of electromagnetic radiations emitted by atoms
- C. Intensities of electromagnetic radiations absorbed by atoms
- D. All of these options✓
- E. Both B and C
Explanation: The correct answer is D: All of these options. Atomic spectra encompass the study of both the wavelengths and the intensities of electromagnetic radiation emitted and absorbed by atoms. When electrons transition between energy levels, they emit or absorb photons, whose characteristics—like wavelength and intensity—can be measured. Options A, B, and C all address partial aspects of these measurements, but the full scope of atomic spectra includes all these components.
Why the other options are wrong
- A. The atomic spectra involve measurements of the wavelengths of electromagnetic radiation emitted or absorbed during electron transitions between energy levels.
- B. Atomic spectra also involve measuring the intensities of radiation emitted as electrons move to lower energy levels.
- C. Measurements of the intensities of radiation absorbed during electron transitions to higher energy levels are part of atomic spectra studies.
- E. This option is incomplete as it ignores the measurement of wavelengths, which is a key aspect of atomic spectra.
Q160. What will be the energy in Joules, when an electron acquires a speed of 10 m/s?
- A. 3.61 x 10-19 J
- B. 4.55 x 10-29 J✓
- C. 5.13 x 10-19 J
- D. 6.13 x 10-19 J
- E. 8.71 x 10-19 J
Explanation: KE = 1/2mv2KE = ½(9.11 x 10-31)(10)2KE = 4.55 x 10-29 J
Why the other options are wrong
- A. This value is calculated incorrectly by using an incorrect mass of the electron or speed in the formula for kinetic energy.
- C. This value results from an incorrect application of the kinetic energy formula, possibly due to errors in multiplication or unit conversion.
- D. This value does not correspond to the correct formula application for kinetic energy of an electron at the given speed.
- E. This option reflects a significant overestimation of energy, likely due to calculation errors in either mass or speed.
Q161. In a certain circuit, a transistor has a collector current of 10mA and a base current of 40μA. What is the current gain of the transistor?
- A. 150
- B. 200
- C. 250✓
- D. 300
- E. 350
Explanation: To determine the current gain (β) of a transistor, use the formula: β = IC/IB. Here, the collector current (IC) is 10mA (10 × 10-3 A) and the base current (IB) is 40μA (40 × 10-6 A). Calculating gives:Current gain = (10 × 10-3 A) / (40 × 10-6 A) = 250.Therefore, the correct answer is Option C: 250. The other options (150, 200, 300, 350) do not match the calculated current gain of 250, making them incorrect.
Why the other options are wrong
- A. This option suggests a current gain of 150. To calculate the current gain (β), use the formula: IC/IB. Given IC = 10mA and IB = 40μA, the current gain is 250, not 150. Therefore, this option is incorrect.
- B. This option suggests a current gain of 200. Using the calculation β = IC/IB, with IC = 10mA and IB = 40μA, the result is 250. Thus, this option is incorrect.
- D. This option suggests a current gain of 300. However, by dividing IC (10mA) by IB (40μA), the calculated current gain is 250, not 300. Hence, this option is incorrect.
- E. This option suggests a current gain of 350. Given the values IC = 10mA and IB = 40μA, the correct current gain is 250, not 350. Thus, this option is incorrect.
Q162. Electromagnetic wave theory was proposed by:
- A. Huygen
- B. Fraunhofer
- C. Fresnel
- D. Coulomb
- E. Maxwell✓
Explanation: James Clerk Maxwell is credited with formulating the electromagnetic wave theory in 1864. He proposed that light is a form of electromagnetic radiation, which was a groundbreaking unification of previously separate fields: electricity, magnetism, and optics. His set of equations, known as Maxwell's equations, describe how electric and magnetic fields interact and propagate as waves through space.Other options are incorrect as they contributed to different aspects of physics: Huygens with wave theory of light, Fraunhofer with spectral lines in light, Fresnel with wave optics, and Coulomb with electrostatics.
Why the other options are wrong
- A. Huygens is known for his wave theory of light, but it did not involve electromagnetic waves.
- B. Fraunhofer is recognized for his work with the spectrum of light and dark lines, called Fraunhofer lines, not for electromagnetic wave theory.
- C. Fresnel contributed to wave optics with his understanding of light as a transverse wave, but not electromagnetic wave theory.
- D. Coulomb is famous for his law regarding electrostatic force between charges, not electromagnetic wave theory.
Q163. If the speed of waves is 10m/sec and its frequency is 5Hz, find its wavelength:
- A. 1
- B. 2✓
- C. 4
- D. 6
Explanation: V=F λ λ = v/f λ =10/5 λ = 2m
Why the other options are wrong
- A. Incorrect as per formula
- C. Incorrect as per formula
- D. Incorrect as per formula
Q164. For the adiabatic process, the first law of thermodynamics is:
- A. w = ∆u = Q
- B. Q = -w
- C. Q = w
- D. w = -∆u✓
Explanation: An adiabatic process is one in which no heat is gained or lost by the system. The first law of thermodynamics with Q=0 shows that all the change in internal energy is in the form of work done. This condition can be used to derive the expression for the work done during an adiabatic process. When a gas expands, it does work on the surroundings; compression of a gas to a smaller volume similarly requires that the surroundings perform work on the gas. If the gas is thermally isolated from the surroundings, then the process is said to occur adiabatically. The first law is; ΔQ=ΔU+w In an adiabatic change, q = 0, so the First Law becomes 0=ΔU+w -ΔU=w or ΔU=-wSince the temperature of the gas changes with its internal energy, it follows that adiabatic compression of a gas will cause it to warm up, while adiabatic expansion will result in cooling.
Why the other options are wrong
- A. This option suggests that the work done (w), change in internal energy (Δu), and heat transfer (Q) are all equal, which is not true for an adiabatic process. In an adiabatic process, there is no heat transfer (Q=0), so this option is incorrect.
- B. This option suggests that the heat transfer (Q) is equal to the negative of the work done (w). However, in an adiabatic process, there is no heat transfer (Q=0), so this option is incorrect.
- C. This option suggests that the heat transfer (Q) is equal to the work done (w). However, in an adiabatic process, there is no heat transfer (Q=0), so this option is incorrect.
Q165. If the body is rotating with uniform angular velocity, then its torque is:
- A. Zero✓
- B. 90
- C. 1
- D. -1
Explanation: Torque will be zero because the force on the object is zero, since it is not accelerating. And also if the body is at rest or rotating with uniform angular velocity the angular acceleration will be zero in this case the torque acting on a body will be zero.Torque is given by solution i.e. torque = r.F sin (theta)Here force = maAcceleration is given by change in velocity/timeIf the change in velocity is zero, acceleration is zero, force is zero, thus torque is also zero. Any other value is not remotely possible
Why the other options are wrong
- B. As per the solution, this option is incorrect.
- C. As per the solution, this option is incorrect.
- D. As per the solution, this option is incorrect.
Q166. According to the first law of thermodynamics, ΔU = Q + W, where ΔU Is the increase in internal energy of the system, Q is the heat transferred to the system and W is the external work done by the system.Which of the following is NOT a correct expression?
- A. At constant temperature: Q = -W
- B. When no work is done: ΔU = Q
- C. In gaseous system: ΔU = Q + P Δ V
- D. When work is done by the system: ΔU = Q - W✓
Explanation: There are two sign conventions:1. ∆U= Q+W: Here, work done BYthe gas/system is taken POSITIVE. 2. ∆U= Q-W: Here, work done ON the gas/system is taken NEGATIVE. The equation provided in the question follows the first convention, according to which D is incorrect.
Why the other options are wrong
- A. ΔU = Δ K.E ΔK.E ∝ ΔT Since T is constant, change in temperature will be zero.Thys, ΔK.E is also zero.As, ΔU = ΔK.E, hence, ΔU is also zero.Hence, ∆U= Q+W 0 = Q + WQ = -W
- B. ΔU = Q +Wwhen W = 0ΔU = Q
- C. There are two sign conventions:1. ∆U= Q+W: Here, work done BYthe gas/system is taken POSITIVE. 2. ∆U= Q-W: Here, work done ON the gas/system is taken NEGATIVE in physics.
Q167. Two capacitors C1 = 2µ and C2 = 4µ F are connected in series across in a 100V supply. Find the effective capacitance.
- A. ½ µF
- B. 3/2 µF
- C. 5/2 µF
- D. 4/3 µF✓
- E. 2 µF
Explanation: Recall that the effective capacitance of capacitors in series is the reciprocal of the sum of reciprocals of individual capacitors (just like resistors in parallel)Therefore,1/Ceffective = 1/C1 + 1/C21/Ceffective = ½ +¼ 1/Ceffective = ¾C effective= 4/3 µF Hence option D is the correct answer.
Why the other options are wrong
- A. This option is incorrect.Recall that the effective capacitance of capacitors in series is the reciprocal of the sum of reciprocals of individual capacitors (just like resistors in parallel)Therefore,1/Ceffective = 1/C1 + 1/C21/Ceffective = ½ +¼ 1/Ceffective = ¾C effective= 4/3 µF
- B. This option is incorrect. Recall that the effective capacitance of capacitors in series is the reciprocal of the sum of reciprocals of individual capacitors (just like resistors in parallel)Therefore,1/Ceffective = 1/C1 + 1/C21/Ceffective = ½ +¼ 1/Ceffective = ¾C effective= 4/3 µF
- C. This option is incorrect. Recall that the effective capacitance of capacitors in series is the reciprocal of the sum of reciprocals of individual capacitors (just like resistors in parallel)Therefore,1/Ceffective = 1/C1 + 1/C21/Ceffective = ½ +¼ 1/Ceffective = ¾C effective= 4/3 µF
- E. This option is incorrect. Recall that the effective capacitance of capacitors in series is the reciprocal of the sum of reciprocals of individual capacitors (just like resistors in parallel)Therefore,1/Ceffective = 1/C1 + 1/C21/Ceffective = ½ +¼ 1/Ceffective = ¾C effective= 4/3 µF
Q168. Example(s) of spin motion is/are:
- A. The daily rotation of the earth about its own axis
- B. Jumping of a paratrooper from an helicopter
- C. Flow of a viscous liquid
- D. Rotation of flywheel about its axle
- E. Both the daily rotation of the earth and flywheel about its own axis✓
Explanation: Spin motion is the movement of an object about its own axis, which is depicted by;(i) the daily motion of the earth(ii)flywheel rotation about its own axis.
Why the other options are wrong
- A. Wrong answer.Spin is rotational motion of an object about an axis parallel to the axis of the object such as Earth rotating on its axis, a wheel turning on its axle.
- B. Wrong answer.Spin is rotational motion of an object about an axis parallel to the axis of the object such as Earth rotating on its axis, a wheel turning on its axle.
- C. Wrong answer.Spin is rotational motion of an object about an axis parallel to the axis of the object such as Earth rotating on its axis, a wheel turning on its axle.
- D. Wrong answer.Spin is rotational motion of an object about an axis parallel to the axis of the object such as Earth rotating on its axis, a wheel turning on its axle.
Q169. The following question belongs to the topic of momentum:
- A. Current
- B. Length
- C. Angular momentum✓
- D. Torque
- E. Displacement
Explanation: The correct answer is Angular momentum. In three-dimensional space, the angular momentum of a point particle is defined as the cross product of its position vector (r) with respect to a given origin and its linear momentum vector (p). This forms a pseudovector, which is essential in describing rotational motion in physics. The other options are incorrect because they do not correctly describe the properties or definitions related to momentum or angular momentum. 'Current' relates to electric charge flow, 'Length' and 'Displacement' relate to measures of distance, and 'Torque' is a measure of rotational force, not a type of momentum.
Why the other options are wrong
- A. This option is incorrect because current is related to the flow of electric charge, not momentum.
- B. This option is incorrect because length is a measure of distance, not related to momentum or angular momentum.
- D. This option is incorrect because torque is a measure of the force that causes rotation, not a form of momentum.
- E. This option is incorrect because displacement refers to a change in position, not related directly to momentum.
Q170. The amount of heat provided to a system at constant pressure (qp) is equal to _.
- A. Change in internal energy (ΔU)
- B. Change in enthalpy (ΔH)✓
- C. Change in free energy (ΔG)
- D. Change in temperature only (ΔT)
- E. Change in pressure only (ΔP)
Explanation: At constant pressure, the heat added to a system is equal to the change in enthalpy (ΔH). This is because enthalpy is defined as the sum of the internal energy and the product of pressure and volume (H = U + PV). Therefore, when heat is added at constant pressure, it primarily changes the enthalpy. Option B is correct. Option A is incorrect because internal energy change (ΔU) does not account for the work done by the system, while Option C (ΔG) involves entropy and is related to the spontaneity of reactions, not just heat change. Options D and E are unrelated to the direct measure of heat at constant pressure.
Why the other options are wrong
- A. Internal energy refers to the sum of all kinetic and potential energies of the molecules within a system. It changes due to heat and work done, but at constant pressure, the focus is on enthalpy rather than internal energy.
- C. Free energy change, ΔG, is related to the spontaneity of a reaction and involves both enthalpy and entropy, but it is not directly equal to the heat provided at constant pressure.
- D. While temperature is related to the energy of a system, the change in temperature alone does not account for the heat provided at constant pressure.
- E. The heat provided at constant pressure affects the enthalpy, not just the pressure. ΔP alone does not encompass the heat exchange at constant pressure.
Q171. A 10 nanofarad (10 x 10-9 F) parallel plate capacitor holds a charge of magnitude 50 µC on each plate.If the plates are separated by a distance of 0.885mm, what is the area of each plate?
- A. 1.0 m2✓
- B. 3.0 m2
- C. 5.5 m2
- D. 7.5 m2
Explanation: To find the area of each plate, we use the formula for the capacitance of a parallel plate capacitor: C = ε0 * (A/d), where C is the capacitance, ε0 is the permittivity of free space (approximately 8.85 x 10-12 F/m), A is the area of the plates, and d is the distance between the plates. Given C = 10 x 10-9 F and d = 0.885 x 10-3 m, we rearrange the formula to solve for A: A = (C * d) / ε0. Plugging in the values gives A = (10 x 10-9 F * 0.885 x 10-3 m) / 8.85 x 10-12 F/m = 1.0 m2. Thus, Option A is correct. The other options provide areas that are either too large or too small when calculated properly with the given values.
Why the other options are wrong
- B. This answer is incorrect. Using the capacitance formula with the given values leads to a smaller area.
- C. This answer is incorrect. The calculation does not support this larger area given the capacitance and charge.
- D. This answer is incorrect. Such a large area is not consistent with the physical parameters provided in the question.
Q172. If '-' means'+', '+' means '-', '*' means '÷' and '÷' means '*' then which of the following will be the correct equation?
- A. 30 + 5 +14 -10 * 15 = 122
- B. 10 + 5 - 14 + 10 * 15 = 158
- C. 30 - 5 + 14 +10 * 15 = 162
- D. 30 * 5 - 4 + 10 - 30 = 30✓
Explanation: Option A: 30 + 5 +14 -10 * 15 = 122= 30 - 5 - 14 + 10 ÷ 15 (substituting the new symbols)= 30 - 5 - 14 + 0 (10 ÷ 15 = 0)= 11Option B: 10 + 5 - 14 + 10 * 15 = 158= 10 - 5 + 14 ÷ 10 - 15 (substituting the new symbols)= 10 - 5 + 1 - 15 (14 ÷ 10 = 1)= -9Option C: 30 - 5 + 14 +10 * 15 = 162= 30 + 5 - 14 - 10 ÷ 15 (substituting the new symbols)= 30 + 5 - 14 - 0 (10 ÷ 15 = 0)= 21 Option D: 30 * 5 - 4 + 10 - 30 = 30= 30 ÷ 5 + 4 - 10 + 30 (substituting the new symbols)= 6 + 4 - 10 + 30 (30 ÷ 5 = 6)= 30
Why the other options are wrong
- A. 30 + 5 +14 -10 * 15 = 122= 30 - 5 - 14 + 10 ÷ 15 (substituting the new symbols)= 30 - 5 - 14 + 0 (10 ÷ 15 = 0)= 11
- B. 10 + 5 - 14 + 10 * 15 = 158= 10 - 5 + 14 ÷ 10 - 15 (substituting the new= 10 - 5 + 1 - 15 (14 ÷ 10 = 1)= -9
- C. 30 - 5 + 14 +10 * 15 = 162= 30 + 5 - 14 - 10 ÷ 15 (substituting the new symbols)= 30 + 5 - 14 - 0 (10 ÷ 15 = 0)= 21
Q173. Statement: I) No rabbit is lion. II) Some horses are lions. III) All rabbits are tables.Conclusions:I) Some tables are lions.II) Some horses are rabbits.III) No lion is table.
- A. Only I and II
- B. Only III follows
- C. Only II and III follow
- D. None follows✓
Explanation: To determine which conclusions logically follow from the premises, we analyze each statement:- Conclusion I: Some tables are lions. This cannot be determined as the statements do not establish any direct or indirect connection between tables and lions.- Conclusion II: Some horses are rabbits. This is contradicted by statement I, which says no rabbits are lions; since some horses are lions, they cannot be rabbits.- Conclusion III: No lion is table. While it may seem logical since all rabbits are tables and no rabbits are lions, the premises do not explicitly support this conclusion. The relationship between lions and tables is not defined in the provided statements.Therefore, none of the conclusions logically follow from the premises, making Option D the correct choice.
Why the other options are wrong
- A. This option suggests that both conclusions I and II are valid. However, conclusion I cannot be conclusively drawn from the premises, and conclusion II contradicts statement I, making this option incorrect.
- B. This option asserts that conclusion III is valid. While conclusion III may seem plausible due to the relationship between rabbits and tables, it is not explicitly supported by the premises, making this option incorrect.
- C. This option claims both conclusions II and III are true. Since conclusion II contradicts statement I and conclusion III is not supported by the premises, this option is also incorrect.
Q174. Statement: A large number of students are reported to be dropping out of school in villages as their parents want their children to help them in farms.Courses of Action:I. The government should immediately launch a programme to create awareness among the farmers about the value of education.II. The government should offer incentives to those farmers whose children remain in schools.III. Education should be made compulsory for all children up to the age of 14 and their employment banned.
- A. Only I and II follow
- B. Only II and III follow
- C. Only I and III follow
- D. All follow✓
Explanation: Literacy at basic level is the utmost need to prepare good future citizens. So, all children need to be educated. This can be achieved by creating awareness, providing incentives, enforcing education and banning employment of children. Thus, all the three courses follow.
Why the other options are wrong
- A. This is incorrect according to the interpretation.Literacy at basic level is the utmost need to prepare good future citizens. So, all children need to be educated. This can be achieved by creating awareness, providing incentives, enforcing education and banning employment of children. Thus, all the three courses follow.
- B. This is incorrect according to the interpretation.Literacy at basic level is the utmost need to prepare good future citizens. So, all children need to be educated. This can be achieved by creating awareness, providing incentives, enforcing education and banning employment of children. Thus, all the three courses follow.
- C. This is incorrect according to the interpretation.Literacy at basic level is the utmost need to prepare good future citizens. So, all children need to be educated. This can be achieved by creating awareness, providing incentives, enforcing education and banning employment of children. Thus, all the three courses follow.
Q175. Statement: Most of the steel producing companies in the country have made considerable profit during the last financial year. Many Asian countries have been importing huge quantities of steel from Pakistan
- A. Statement II is the cause and statement I is its effect
- B. Statement I is the cause and statement II is its effect
- C. Both statements I and II are independent causes
- D. Both statements I and II are effects of some common cause✓
Explanation: The correct answer is that both statements I and II are effects of some common cause. Statement I talks about steel companies making profit, which is likely the effect of the cause mentioned in statement II - many Asian countries importing steel from Pakistan. The explanation shows how the import of steel from Pakistan leads to increased profits for the country's steel companies. The other options are incorrect as they do not capture the cause-effect relationship between the statements accurately.
Why the other options are wrong
- A. This is incorrect because statement II does not directly cause statement I. While importing more steel can influence profits, the statements may both be effects of a third factor, such as increased global demand.
- B. This is incorrect because the profitability of steel companies does not directly cause an increase in steel imports by Asian countries.
- C. This is incorrect because there is a logical connection between the two statements suggesting they are not entirely independent.
Q176. Statement:The Management of School M has decided to give free breakfast from next academic year to all the students in its primary section through its canteen even though they will not get any government grant.Courses of Action:I. The school will have to admit many poor students who will seek admission for the next academic year.II. The canteen facilities and utensils have to be checked and new purchases to be made to equip it properly.III. Funds will have to be raised to support the scheme for years to come.
- A. Only II and III follows✓
- B. Only III and I follow
- C. Only I and II follow
- D. Only I follows
Explanation: Since the school has introduced the scheme without receiving any grant, it needs to pool up the funds and make adequate arrangements to keep the scheme going. So, only II and III follow.
Why the other options are wrong
- B. Since the school has introduced the scheme without receiving any grant, it needs to pool up the funds and make adequate arrangements to keep the scheme going. So, only II and III follow.
- C. Since the school has introduced the scheme without receiving any grant, it needs to pool up the funds and make adequate arrangements to keep the scheme going. So, only II and III follow.
- D. Since the school has introduced the scheme without receiving any grant, it needs to pool up the funds and make adequate arrangements to keep the scheme going. So, only II and III follow.
Q177. What should come next: save, secure, protect, -----
- A. Guard✓
- B. Lock
- C. Conserve
- D. Humble
Explanation: Save is a synonym of secure so to follow the pattern the answer needs to be a synonym of protect, which is guard. So, the correct option is A.
Why the other options are wrong
- B. While "lock" is related to security, it is not a logical continuation in the context of the given sequence. The previous words suggest a progression of actions, not an item.
- C. "Conserve" does not fit the sequence as it implies preservation or using resources wisely, which is not directly connected to the themes of saving, securing, or protecting.
- D. "Humble" is entirely unrelated to the sequence and does not align with the concepts of saving, securing, or protecting, making it an inappropriate choice.
Q178. Pick the odd word out:
- A. Just
- B. Fair
- C. Equitable
- D. Biased✓
Explanation: The words "just," "fair," and "equitable" are all synonyms related to impartiality and justice. "Biased" is an antonym, meaning to show prejudice for or against something, making it the odd one out.
Why the other options are wrong
- A. 'Just' means being based on or behaving according to what is morally right and fair, which is aligned with honesty.
- B. 'Fair' suggests treating people equally without favoritism or discrimination, closely related to honesty and impartiality.
- C. 'Equitable' refers to dealing fairly and equally with all concerned, synonymous with justice and fairness.
Q179. Each problem consists of three statements. Based on the first two statements, the third statement may be true, false, or uncertain.Blueberries cost more than strawberries.Blueberries cost less than raspberries.Raspberries cost more than both strawberries and blueberries.If the first two statements are true, the third statement is:
- A. True✓
- B. False
- C. Uncertain
- D. None of these
- E. None of these
Explanation: The first two statements provide a clear hierarchy of fruit prices: blueberries are more expensive than strawberries, and raspberries are more expensive than blueberries. Therefore, raspberries must be more expensive than both strawberries and blueberries, making the third statement true. Option A is correct as it accurately reflects this deduction. Options B and C are incorrect because the cost relationships provided lead to a definite conclusion about the third statement. Option D is also incorrect as it suggests there is no correct option, which contradicts the evidence given.
Why the other options are wrong
- B. This is incorrect because the first two statements confirm that raspberries are more expensive than blueberries and strawberries, validating the third statement as true.
- C. This is incorrect as the relationships given in the first two statements are sufficient to determine that the third statement is true.
- D. This is incorrect because option A is the correct answer, given the information provided in the first two statements.
- E. As option A is correct it's incorrect
Q180. Passage: A, P, R, X, S and Z are sitting in a row. S and Z are in the centre, and A and P are at the ends. R is sitting on the left of A. Then who is sitting on the right of P?
- A. A
- B. S
- C. X✓
- D. Z
Explanation: The statement "R is sitting on the left of A" establishes the orientation. If A is at one end and R is to his left, A must be at the right end. This makes P the left end. With S and Z in the center, the only person left to sit between P and the center is X. The order is P, X, (S, Z), R, A.
Why the other options are wrong
- A. A is at one end of the row, and given that R is to the left of A, A cannot be to the right of P.
- B. S is positioned in the center, so it cannot be directly adjacent to P, who is seated at an end.
- D. Z is in the center, adjacent to S, and cannot be directly to the right of P, who is at one end.
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