Sindh Mdcat 2024 — Solved Past Paper with Answers

Q1. Spot the error in the given sentence:The stories that she makes up for the children ought to be written down and published.

• A. For
• B. Down
• C. Ought
• D. Stories
• E. No error✓

Explanation: The sentence 'The stories that she makes up for the children ought to be written down and published.' is grammatically correct. Each component of the sentence, including the preposition 'for', the phrase 'written down', and the modal verb 'ought', is used appropriately. The structure of the sentence clearly conveys that the stories are intended for children and should be recorded and published. Therefore, there is no error in the sentence. The other options suggest components that are actually used correctly, which confirms that the sentence itself stands without error.

Q2. Read the passage and choose the best option:As the big door swung behind me, I heard the sound of a roar of laughter that went up to the roof of the bank. Since then I use a bank no more. I keep my money in my pocket and my savings in silver dollars in a sock.Where did the writer put his savings in?

• A. Pocket
• B. Silver box
• C. Bank
• D. Sock✓

Explanation: Option D is correct, as the writer put his savings in socks.

Q3. Choose the correct option:

• A. He managed to write a letter to his son.
• B. He was very ill, he managed to write a letter to his son.
• C. He managed to write a letter to his son although he was very ill.
• D. Although he was very ill, he managed to write a letter to his son.✓

Explanation: Option D is correct. This option is correct. This is the best option as it clearly states the condition first and shows that despite being ill, he still managed to write the letter, enhancing the contrast.

Q4. Read the passage below and choose the best option for the statement:John Keats (1795-1821) was born in London and educated at the Enfield School, where a sympathetic headmaster inspired his passion for literature. After leaving school, he qualified himself for surgery but abandoned it for poetry. He published his first volume of verse in 1817 and "Endymion" in 1818. 1818 was indeed a tragic year for Keats. His brother Tom, whom he nursed devotedly through his last illness, died of Tuberculosis. Soon after his brother's death, Keats himself developed symptoms of the same disease. In a vain attempt to save his health and life, some of Keats' friends arranged for him to go to Italy. He died and was buried at Rome. His death at an early age was perhaps the greatest disaster to befall English poetry.John Keats and his brother died of this disease:

• A. Diabetes
• B. Alzheimer's disease
• C. Pneumonia
• D. Tuberculosis
• E. Tuberculosis✓

Explanation: Tuberculosis is correct. The passage states that both Keats' brother Tom and Keats himself died of tuberculosis.

Q5. Choose the correct phrase for the sentence given below:The aeroplane travelled 5,000 meters before it took on.

• A. Take into
• B. Took off✓
• C. Take over
• D. Took away
• E. Take on

Explanation: The correct answer is 'Took off'. This phrasal verb is commonly used to describe an airplane beginning its flight. The other options do not convey the intended action of an airplane starting to fly. 'Take into' is not a proper phrasal verb in this context, 'Take over' suggests assuming control, 'Took away' implies removal, and 'Take on' suggests assuming responsibility, none of which are suitable for the situation described in the sentence.

Q6. Choose the best possible option from the given homophones:How will they get across the river if the _ is not running?

• A. Furry
• B. Fairly
• C. Fairy
• D. Ferry✓
• E. Fury

Explanation: Option D is correct. This option is correct. Ferry is a boat or ship that carries people or goods across a body of water, making it the correct choice.

Q7. Choose the best possible antonym for the underlined word:The general's problem was to get 20,000 troops swiftly across this river.

• A. Slowly✓
• B. Thoroughly
• C. Anxiously
• D. Strongly

Explanation: Option A is correct. Slowly directly opposes "swiftly," meaning at a reduced speed or without haste.

Q8. Choose the correct sequenced option for the underlined words in the paragraph below:_ the invention of the personal computer and the internet, a new age in communications begins. _ people could communicate fastest and more easily than ever before. _, _ and storing information became quick and easy. It was no _ necessary to write draft after draft when changes could be made so easily using a _ processor program.

• A. Longer - With - Faster - Writing - Editing - Word - Now
• B. With - Now - Writing - Editing - Longer - Word - Faster
• C. With - Now - Faster - Writing - Editing - Longer - Word
• D. With - Now - Faster - Writing - Editing - Longer - Word✓

Explanation: Option D is the correct sequence as it maintains a coherent narrative flow. It begins with 'With the invention of the personal computer...', which clearly sets the stage for the advancements in communication. Following this, 'Now' emphasizes the current state of technology, while 'Faster' highlights the improvement in communication speed. The sequence continues logically with 'Writing' and 'Editing', which describe the ease associated with these tasks due to technological advancements.Finally, 'Longer' is used to contrast the previous complexity in writing drafts, and 'Word' processor wraps up the statement by referring to the specific technology that facilitates these changes.

Q9. The synonym of the word "Oblivion" is:

• A. Forgetfulness✓
• B. Observant
• C. Neglect
• D. Daunted

Explanation: The correct answer is Option A: Forgetfulness. 'Oblivion' refers to a state of being forgotten or the condition of being unaware or unconscious. 'Forgetfulness' captures this idea because it implies a lack of memory or awareness.Observant is incorrect because it means being attentive and aware.Neglect is incorrect because it refers to a lack of care, not a state of being forgotten.Daunted is incorrect as it relates to feeling intimidated or discouraged, not forgotten.

Q10. Choose the best option:Some of the race teams were still looking for _ equipment.

• A. Its
• B. It's
• C. There
• D. Their✓
• E. It

Explanation: Option D is correct. This option is correct. Their is the possessive form for "they," indicating that the equipment belongs to the race teams, making it the correct choice.

Q11. Read the passage and choose the best option:Nobody has ever been able to compute with any exactness how many people took part in the great rout of 1913, for the panic, which extended from the Winslow Bottling Works in the south and to Clintonville, six miles north, ended abruptly as it began. The shouting, weeping, tangled evacuation of the city lasted not more than two hours in all. Few people got as far east as Reynoldsburg, twelve miles away; fifty or more reached the Country Club, eight miles away; most of the others gave up, exhausted, or climbed trees in Franklin Park, four miles out.Most of the people gave up and climbed trees in:

• A. Winslow Bottling Works
• B. Clintonville
• C. Country Club
• D. Franklin Park✓

Explanation: The correct answer is Franklin Park because the passage specifically mentions that most of the people gave up and climbed trees there. The other options are areas mentioned as boundaries or destinations that only a few people reached, making them incorrect choices for where most people ended up.

Q12. Choose the correct prepositional phrase for the sentence given below:In today's session, he _the current situation of Pakistan.

• A. Suffers from
• B. Belongs to
• C. Begs for
• D. Compares with
• E. Comments on✓

Explanation: This is correct because "comment on" is the right phrase used when someone is expressing their opinion or making a statement about something, like a situation.

Q13. Spot the error in the given sentence:The bushes on the corner make it difficult for the driver to see the traffic approaching from the write.

• A. Write✓
• B. For
• C. Make
• D. Approaching
• E. Bushes

Explanation: Option A is correct. This option is correct. Write is a misspelling of right, which refers to the direction from which the traffic is approaching. The correct word should be "right" instead of "write."

Q14. Punctuate the following sentence:He said will you have time to play regularly

• A. He said,"Will you have time to play regularly?"✓
• B. He said, Will you have time to play regularly?
• C. He said, "Will you have time to play regularly."
• D. He said "Will you have time to play regularly'.
• E. He said, 'Will you have time to play regularly'.

Explanation: Option C is correct. This option is correct. This option is correct as it uses the proper quotation marks and punctuation for a direct question.

Q15. Complete the main clause of the following sentence:If I went to Paris, _

• A. I can see the Eiffel Tower
• B. I must see the Eiffel Tower
• C. I should see the Eiffel Tower
• D. I could see the Eiffel Tower
• E. I would see the Eiffel Tower✓

Explanation: "If I went" is a past subjunctive, used to express a hypothetical or unreal condition. The appropriate verb to match this tense is "would", which indicates a possible outcome in that hypothetical situation.

Q16. Correct the spelling & capitalization errors in the paragraph below:It was in korea, june 1953. I had been wounded, and they had strapt me on a stretcher and dumped me by the roadside to wait for an ambulance, if I didn't pegg out first. I wanted to die anyway. I had nothing to live for. The pain was pretty bad, I guess I fainted. When I came to, there was a korean girl sitting beside me. She was about fourteen; not pretty, of course; but friendly blue eyes and long plates hanging in front of her shoulders. She didn't say anything. She just smiled. And I smiled back.

• A. Korea - Pretty - Fainted-Korean - Sitting - Blue - Plaits - Shoulders
• B. Strapped - Roadside - Peg - Pretty - Fainted - Korean - Sitting - Blue - Plaits - Shoulders
• C. Korea - Strapped - June - Peg - Pretty - Fainted - Korean - Sitting - Blue - Plaits - Shoulders✓
• D. Korea - Strapped - Roadside - Peg - Sitting - Blue - Plaits - Shoulders
• E. Korea - June - Strapped - Pretty - Blue - Plaits - Shoulders

Explanation: Korea and June: These are proper nouns and need to be capitalized.Peg: The phrase "peg out" is a colloquial expression meaning "die," and "peg" is correctly used.Pretty: "Pretty" needs to be capitalized because it is in the middle of the sentence following a semicolon.Fainted: This should be in lowercase, unless it's at the start of a sentence. Here it is correctly used.Korean: As an adjective describing nationality, it needs to be capitalized.Sitting: This is correctly capitalized since it's after a period and begins a sentence.Blue: A color adjective, it should be lowercase unless starting a sentence.Plaits: "Plaits" (braids) is the correct spelling instead of "plates."Shoulders: Correctly used, describing where the plaits hang.

Q17. Choose the correct form of the tense:I would gladly have helped him if he _me into confidence.

• A. Took
• B. Has taken
• C. Had taken✓
• D. Have taken
• E. Takes

Explanation: This is the correct form because it is in the past perfect tense, which is used to indicate an action that was completed before another past action (in this case, the helping). The phrase sets up a conditional situation that did not occur in the past.

Q18. Fill in the blank with the appropriate preposition. The thief made an escape by _.

• A. Climbing up the wall
• B. Climbing on the wall
• C. Climbing to the wall
• D. Climbing over the wall✓
• E. Climbing into the wall

Explanation: "Climbing over the wall" indicates that the thief physically ascended the wall and then descended or moved beyond it, which aligns with the idea of escaping.Only "Climbing over the wall" effectively conveys the action of the thief successfully escaping by moving beyond the wall. The other options either limit the action to climbing without implying escape or suggest inappropriate directions or actions.

Q19. Stimuli such as pressure, touch, stretch, and motion stimulate which of the following receptors?

• A. Thermoreceptors
• B. Mechanoreceptors✓
• C. Gustatory receptors
• D. Olfactory receptors

Explanation: Mechanoreceptors are sensory receptors that respond to mechanical stimuli, such as pressure, touch, vibration, and stretch. They are found in the skin, muscles, and internal organs and play a crucial role in the sense of touch and proprioception (awareness of body position).

Q20. The situation when two alternative forms are expressed completely is said to have:

• A. Codominance✓
• B. Sex-influenced traits
• C. Multiple alleles
• D. Incomplete dominance
• E. Sex-limited traits

Explanation: Codominance is a genetic scenario where both alleles in a heterozygous individual are fully expressed, leading to a phenotype that exhibits traits from both alleles. For instance, in certain flowers, one allele may be responsible for producing red petals while another produces white petals; in the case of codominance, the resulting flowers can display both red and white petals concurrently.

Q21. The bacterium, with a tuft of flagella present at each of the two poles, is called:

• A. Amphitrichous✓
• B. Lophotrichous
• C. Peritrichous
• D. Monotrichous

Explanation: Amphitrichous refers to a type of bacterial flagellation where a single flagellum is present at both ends of the cell. This arrangement allows for movement in both directions, giving the bacteria greater mobility and versatility in navigating their environment.

Q22. What is the correct order of organelles in ultracentrifugation?

• A. Ribosome → Nuclei → Mitochondria
• B. Lysosome → Ribosome → Mitochondria
• C. Nuclei→ Mitochondria✓
• D. Mitochondria → Nuclei → Golgi bodies
• E. Ribosome → Nuclei → Golgi bodies

Explanation: The correct order of organelles in ultracentrifugation, based on their size and density, is as follows: 1. Nuclei 2. Mitochondria Here's the explanation: Nuclei are the largest and heaviest organelles, so they sediment first. Mitochondria, while smaller than nuclei, are still quite dense, which is why they sediment next. Smaller and less dense organelles, such as ribosomes and Golgi bodies, sediment later at higher centrifugal forces.

Q23. A peptide hormone released from Sertoli cells that inhibits the secretion of FSH is:

• A. Testosterone
• B. GnRH
• C. FSH
• D. Inhibin✓
• E. Luteinizing hormone

Explanation: Inhibin is a hormone produced by the gonads (ovaries in females and testes in males) that inhibits the secretion of follicle-stimulating hormone (FSH) from the pituitary gland. It helps regulate reproductive functions by providing feedback to control the levels of FSH, thereby playing a role in regulating sperm production in males and follicle development in females.

Q24. Name the protein complex that stabilizes the separated strand of DNA during replication:

• A. Double Stranded binding proteins
• B. Double-stranded binding enzymes
• C. Single-stranded binding proteins✓
• D. Single-stranded binding enzyme

Explanation: Single-stranded (SSBs) are proteins that bind to single-stranded DNA during processes such as DNA replication and repair. They stabilize the unwound DNA strands, preventing them from re-annealing or forming secondary structures. By keeping the strands separate, SSBs allow other enzymes, like DNA polymerases, to access the DNA for replication and repair.

Q25. Which of the following is not essential for photosynthesis?

• A. Oxygen✓
• B. Chlorophyll
• C. ATP
• D. Light

Explanation: Oxygen is a chemical element (symbol O) essential for life on Earth. It is a colorless, odorless gas that makes up about 21% of the Earth's atmosphere. Oxygen is crucial for cellular respiration in most organisms, allowing them to produce energy by converting glucose and other nutrients. It also plays a key role in combustion and is involved in various chemical reactions.

Q26. Which size of sponge can filter an entire residential pool in one day?

• A. Tennis ball-sized
• B. Ladle-sized
• C. Basketball-sized✓
• D. Hockey ball-sized
• E. Teaspoon-sized

Explanation: The correct answer is Option C: Basketball-sized. This size of sponge provides the necessary surface area and volume to handle the filtration of a large body of water, such as a residential pool, in a single day. Smaller sponges, like those the size of a tennis ball, ladle, hockey ball, or teaspoon, do not have sufficient capacity to filter such a large volume effectively within 24 hours.

Q27. Proteins that cause disease in humans and animals are called:

• A. Prions✓
• B. Viroid
• C. Prophage
• D. Bacteriophage
• E. Antigens

Explanation: Prions are misfolded proteins that can induce other proteins to also misfold, leading to the accumulation of abnormal protein structures in cells. This can result in neurodegenerative diseases, such as Creutzfeldt-Jakob disease in humans and mad cow disease in cattle. Prions are unique because they can propagate without nucleic acids (DNA or RNA), making them distinct from other infectious agents like bacteria and viruses.

Q28. Koshland proposed a model for enzymes with the name of "induced fit model" in the year:

• A. 1959✓
• B. 1952
• C. 1954
• D. 1956
• E. 1949

Explanation: Koshlan proposed the "Induced Fit Model" of enzyme action in the year 1959.

Q29. Why do ribosomes require Mg²+ ions?

• A. To synthesize protein
• B. To transport amino acid to ribosome
• C. To stabilize the ribosomal structure✓
• D. To develop mRNA molecules
• E. To break down RNA molecules

Explanation: Ribosomes are complex structures made of RNA and proteins. The RNA molecules have a lot of negative charges due to their phosphate backbone. Mg²⁺ ions help to neutralize these charges, acting like a "glue" to hold the different components of the ribosome together. This stability is crucial for the ribosome to function properly

Q30. Hemoglobin fails to carry sufficient oxygen, leading to the death of a person then Glutamic acid is replaced by valine at which position?

• A. 3rd position
• B. 6h position✓
• C. 5th position
• D. 4th position

Explanation: The sixth position of the beta globin chain of the hemoglobin molecule is where glutamic acid is replaced by valine.

Q31. The formation of hard uric acid crystals in the joints is identified as:

• A. Rheumatoid arthritis
• B. Ankylosing spondylitis
• C. Osteoarthritis
• D. Callus
• E. Gout✓

Explanation: Gout is a form of inflammatory arthritis caused by the buildup of uric acid crystals in the joints.

Q32. Which virus kills cancer cells and aids immunity?

• A. Saccharomyces
• B. Lactobacillus
• C. Penicillium
• D. Lymph Bacterium
• E. Oncolytic✓

Explanation: Oncolytic viruses are viruses designed or naturally able to infect and destroy cancer cells while sparing normal tissue. They enter tumor cells, replicate inside them, and eventually cause those cells to break apart, which helps shrink the tumor and also alerts the immune system to attack remaining cancer cells.

Q33. The pigment in the muscles responsible for the binding of oxygen is:

• A. Oxyhemoglobin
• B. Plasmin
• C. Myoglobin✓
• D. Heme
• E. Hemoglobin

Explanation: Myoglobin is a protein found in muscle tissue that binds oxygen.

Q34. In Gram -ve bacteria, the peptidoglycan layer is:

• A. Condensed
• B. Thick
• C. Moderate
• D. Thin✓
• E. Entangled

Explanation: In gram-negative bacteria, the peptidoglycan layer is relatively thin compared to gram-positive bacteria.

Q35. The human enzymes are highly active at about:

• A. 8°C
• B. 15°C
• C. 37°C✓
• D. 45°C
• E. 55°C

Explanation: The optimum temperature for enzyme action in humans is typically around 37°C (98.6°F), which is the normal body temperature. At this temperature, enzymes generally exhibit the highest activity.

Q36. The locomotion in segmented worms is brought about by:

• A. True Pods
• B. Pseudopodia
• C. Setae✓
• D. Peritrichous flagella

Explanation: Locomotion in segmented worms, such as earthworms, occurs through a combination of muscular contractions and the movement of their bristle-like structures called setae. These worms have circular and longitudinal muscles that work together to elongate and shorten the body.

Q37. The type of carbohydrates, made up of 6 to 10 monosaccharides, which are comparatively less sweet in taste and less soluble in water, are called:

• A. Oligosaccharides✓
• B. Monosaccharides
• C. Starch
• D. Cellulose
• E. Polysaccharides

Explanation: Oligosaccharides are carbohydrates composed of a small number (typically 2 to 10) of monosaccharide units linked together by glycosidic bonds. They can be found in various foods and are important for human health, serving as prebiotics that promote gut health and supporting immune function. Oligosaccharides are often found in legumes, onions, and garlic, and they can contribute to the flavor and texture of food.

Q38. The technique is used to determine the growth of bacteria, rate of photosynthesis, and minute quantity of DNA:

• A. Electrophoresis
• B. Micrometry
• C. Microscopy
• D. Chromatography
• E. Spectrophotometry✓

Explanation: Spectrophotometry is a quantitative analytical technique used to measure the absorbance or transmittance of light by a substance. It relies on the principle that different substances absorb light at specific wavelengths, allowing for identification and quantification.

Q39. Which of the following is an example of a sub-viral particle that infects plants?

• A. Prion
• B. Viroid✓
• C. Bacteriophage
• D. Infectious protein

Explanation: Viroids are small, circular RNA molecules that can infect plants. They lack a protein coat and do not encode proteins, relying on the host's cellular machinery for replication. Viroids are responsible for various plant diseases, disrupting normal growth and development

Q40. In heterotrophs, during digestion, macromolecules are broken into monomers by hydrolysis with the help of:

• A. Chymosin
• B. Gastrin
• C. Rennin
• D. Hydrolytic enzyme✓
• E. Endonuclease

Explanation: Hydrolytic enzymes are enzymes that catalyse the breakdown of complex molecules by adding water (hydrolysis). They facilitate the cleavage of chemical bonds in substrates, resulting in smaller molecules.

Q41. Animals that have a ladder-type nervous system, consisting of two nerve cords and connecting nerves that look like a ladder, belong to the phylum:

• A. Protozoa
• B. Coelenterata
• C. Cnidarian
• D. Porifera
• E. Platyhelminthes✓

Explanation: The ladder-like nervous system in flatworms features a centralized cerebral ganglion (brain) at the front, with two longitudinal nerve cords running along the body. Transverse nerves connect these cords, allowing for coordinated movement and responses to stimuli.

Q42. The term enzyme was coined by:

• A. Darwin
• B. Lamarck
• C. Friedrich Wilhelm Kuhn✓
• D. Mendel
• E. Thomas Cech

Explanation: The term enzyme was coined by the German physiologist Wilhelm Kühne in 1878. Kühne used the term to describe the catalytic substances found in living organisms that facilitate biochemical reactions.

Q43. Which lipophilic hormone is found in every tissue of the body and is involved in dealing with inflammation, blood flow, and protection from injury?

• A. Estradiol
• B. Aldosterone
• C. Testosterone
• D. Prostaglandins✓
• E. Oestrogen

Explanation: Prostaglandins are lipid compounds derived from fatty acids that have various physiological functions in the body. They act as local hormones, influencing processes such as inflammation, pain perception, blood flow, and the regulation of blood pressure. Prostaglandins play a key role in the menstrual cycle, mediating uterine contractions, and are involved in the healing process by promoting inflammation. They are produced in response to injury or infection and have diverse effects depending on their specific types and the tissues in which they act.

Q44. Hardy-Weinberg Equation is:

• A. p² + 2pq + q2= 1✓
• B. p + 2pq + q = 1
• C. p + 2pq + q - 0
• D. 2p + q² = 1
• E. 2p + 2q = 1

Explanation: The Hardy-Weinberg equation, p² + 2pq + q2= 1, is used to predict the genetic variation of a population at equilibrium. In this equation, p represents the frequency of one allele, and q represents the frequency of the other allele in a diploid organism. The term p² represents the frequency of the homozygous genotype for the first allele, q² represents the frequency of the homozygous genotype for the second allele, and 2pq represents the frequency of the heterozygous genotype. This equation is a cornerstone of population genetics, illustrating how allele and genotype frequencies remain constant from generation to generation in the absence of evolutionary influences.Options B, C, D, and E are incorrect because they do not correctly represent the relationship between allele and genotype frequencies as outlined by the Hardy-Weinberg principle.

Q45. F.C Steward used this plant for his experiment i.e (tissue culture):

• A. Radish
• B. Corn
• C. Maize
• D. Carrot✓
• E. Mango

Explanation: The correct answer is Carrot. F.C Steward was a pioneer in plant tissue culture and used carrot phloem tissue to show that plant cells have the ability to develop into a whole plant, which is a demonstration of cellular totipotency. This was a significant breakthrough in biotechnology, as it laid the groundwork for modern plant tissue culture techniques. Radish, corn, maize, and mango were not used in Steward's experiments, which focused specifically on the carrot.

Q46. Histone proteins are rich in:

• A. Basic amino acid✓
• B. Acidic fatty acid
• C. Başic citric acid
• D. Acidic amino acid

Explanation: Basic amino acids are amino acids that have a positively charged side chain at physiological pH (around 7.4), due to the presence of an additional amino group (-NH₃⁺) in their side chains. These amino acids can accept protons (H⁺), making them basic.They are found in histones.

Q47. The site of maturation and storage of sperms is:

• A. Seminal vesicles
• B. Scrotum
• C. Testes
• D. Epididymis✓
• E. Vasa deferentia

Explanation: The epididymis is a coiled tube located at the back of each testis. Its primary function is to store and mature sperm produced in the testes. Sperm travel from the seminiferous tubules of the testes to the epididymis, where they undergo maturation, gaining motility and the ability to fertilize an egg. The epididymis also reabsorbs excess fluid and damaged sperm. During ejaculation, sperm are propelled from the epididymis into the vas deferens for transport.

Q48. A disease resulting in complete lack of spermatozoa in ejaculate is:

• A. Azoospermia✓
• B. Obstruction
• C. Oligospermia
• D. Zoospermia
• E. Ejaculation disorder

Explanation: Azoospermia is a medical condition characterized by the absence of sperm in a man's semen. This condition can result from various factors, including hormonal imbalances, blockages in the reproductive tract, or issues with sperm production in the testes

Q49. The type of bacteria which oxidize CO into CO2 is:

• A. Norcardia salmonicolor
• B. Hydrogenomonas
• C. Pseudomonas✓
• D. Thiobacillus
• E. Azobacter

Explanation: The correct answer is Pseudomonas because some species within this genus have the unique ability to oxidize carbon monoxide (CO) as a source of energy, facilitating their survival in environments where CO is present. The other options are incorrect because:Norcardia salmonicolor is involved in the degradation of organic compounds, not CO oxidation.Hydrogenomonas utilizes hydrogen rather than carbon monoxide.Thiobacillus is associated with sulfur and carbon cycles but does not oxidize CO.Azobacter is known for nitrogen fixation and does not rely on carbon monoxide for energy.Thus, Pseudomonas stands out as the only correct option in this context.

Q50. What structure holds sister chromatids together?

• A. Gene
• B. Nucleosome
• C. Centrosome
• D. Centromere✓

Explanation: A centromere is a region of a chromosome that plays a critical role during cell division. It is the constricted region where sister chromatids are held together.

Q51. The most widely accepted explanation for ascent of sap is:

• A. Role of root pressure
• B. Transpiration
• C. Capillarity
• D. Role of atmospheric pressure
• E. Cohesion and transpiration pull✓

Explanation: Cohesion and transpiration pull are two key concepts in the movement of water within plants.Cohesion provides the structural support needed for water movement, while transpiration pull drives the upward flow of water in plants.

Q52. In which of the following environments are plants, with aerenchyma, most likely to be found?

• A. Mesophytes
• B. Sciophytes
• C. Xerophytes
• D. Hydrophytes✓
• E. Halophytes

Explanation: Hydrophytes are aquatic plants that thrive in water-saturated environments.

Q53. Each helix of DNA is made up of four types of nucleotides and both helices are complementary to each other i.e. if one helix contains Adenine the opposite helix will contain:

• A. Histidine
• B. Uracil
• C. Cytosine
• D. Thymine✓

Explanation: According to Chargaff’s base pairing rule:Adenine (A) always pairs with Thymine (T) → by two hydrogen bondsCytosine (C) always pairs with Guanine (G) → by three hydrogen bondsSo,➡ If one helix (strand) contains Adenine,➡ The opposite helix (complementary strand) will contain Thymine.

Q54. Bacteriophages escape from host cells by the activity of:

• A. Non-Ribosome
• B. Lysozyme✓
• C. Peroxisome
• D. Lysosome

Explanation: Lysozyme is an enzyme that plays a crucial role in the immune system and is involved in breaking down bacterial cell walls.

Q55. Which soft-bodied animal is usually Ambisexual?

• A. Tapeworm
• B. Earthworm
• C. Jellyfish
• D. Snail
• E. Oyster✓

Explanation: Oysters are often considered ambisexual due to their ability to change sex during their lifecycle, starting as males and becoming females, depending on environmental conditions.

Q56. The number of teeth in deciduous and permanent teeth is:

• A. 21 and 32 respectively
• B. 18 and 22 respectively
• C. 12 and 32 respectively
• D. 10 and 32 respectively
• E. 20 and 32 respectively✓

Explanation: The correct answers are 20 and 32, respectively. Deciduous teeth, commonly known as baby teeth, total 20 and are typically present from infancy until they are gradually replaced by permanent teeth. Permanent teeth, which include wisdom teeth, sum up to 32 in a complete adult set. Each incorrect option either underestimates the number of deciduous teeth or the number of permanent teeth, which are well-established figures in human dental anatomy.

Q57. Which hormone is responsible to convert the ruptured follicle into a yellowish glandular mass known as corpus luteum?

• A. FSH
• B. ACTH
• C. DHT
• D. LH✓
• E. TSH

Explanation: Luteinizing Hormone (LH) is a key hormone in the reproductive system. In females, it triggers ovulation and helps form the corpus luteum, which produces progesterone essential for maintaining pregnancy

Q58. Phage genome incorporated with host DNA is called:

• A. Bacteriophage
• B. Viroids
• C. Prophage✓
• D. Prions

Explanation: A prophage is the latent form of a bacteriophage (a virus that infects bacteria) when it integrates its genetic material into the bacterial chromosome. In this state, the viral DNA is replicated along with the bacterial DNA during cell division without causing immediate harm to the host. The prophage can remain dormant for extended periods, but under certain conditions, it may reactivate and enter the lytic cycle, leading to the production of new viral particles and the lysis of the bacterial cell. Prophages can play a role in horizontal gene transfer, contributing to genetic diversity among bacteria and sometimes providing advantageous traits, such as antibiotic resistance. Understanding prophages is important in microbiology and virology, particularly in studying bacterial evolution and the dynamics of bacterial infections.

Q59. Plants oxidize sugar in chloroplasts during the day without production of energy. This process is called:

• A. Photorespiration✓
• B. Oxidative phosphorylation
• C. Non-cyclic photophosphorylation
• D. Cyclic oxidative phosphorylation

Explanation: The process you're describing is called photorespiration. During photorespiration, plants take up oxygen and release carbon dioxide, which occurs in chloroplasts when the enzyme RuBisCO reacts with oxygen instead of carbon dioxide. This process can lead to the oxidation of sugar, but it does not produce energy in the way that cellular respiration does.

Q60. Sufficient depolarization in neurolemma results in:

• A. Potassium leakage
• B. Resting membrane potential
• C. Action potential✓
• D. Repolarization
• E. Sub-threshold potential

Explanation: An action potential is a rapid and temporary change in the membrane potential of a neuron or muscle cell that allows for the transmission of electrical signals. It occurs when a stimulus depolarizes the membrane to a threshold level, typically around -55 mV.

Q61. Fusion of two genetically dissimilar parents through artificial pollination is:

• A. Selection
• B. Acclimatization
• C. Hybridization✓
• D. Evolution
• E. Back crossing

Explanation: Hybridization is the process of crossing two different species or varieties to produce a hybrid organism that typically exhibits traits from both parents. This phenomenon occurs in plants and animals and can lead to increased genetic diversity and the introduction of desirable characteristics.

Q62. In the flowering plant, food is translocated in the form of:

• A. Starch
• B. Sucrose✓
• C. Glucose
• D. Sugar
• E. Fructose

Explanation: In flowering plants, the carbohydrate transported long-distance through the phloem is primarily sucrose. Sucrose is a disaccharide (glucose + fructose) that is chemically stable, water-soluble, and non-reducing, so it can be loaded into sieve elements without reacting with cellular components or causing osmotic/chemical damage the way free glucose might. In a typical source (mature leaf) the products of photosynthesis are converted to sucrose and actively loaded into companion cells and then into sieve tube elements (either via plasmodesmatal symplastic routes or by membrane transporters in apoplastic loading).

Q63. Which reaction is also known as Z-scheme?

• A. Oxidative phosphorylation
• B. Cyclic photophosphorylation-
• C. Non-cyclic oxidative phosphorylation
• D. Non-cyclic photephosphorylation✓

Explanation: Non-cyclic photophosphorylation is often illustrated using the Z-scheme model. This model represents the linear flow of electrons during the light-dependent reactions of photosynthesis.

Q64. In gel electrophoresis, how do molecules migrate through the gel?

• A. Under the influence of agar
• B. By diffusion
• C. Under the influence of an electric field✓
• D. Active transport
• E. By osmosis

Explanation: In gel electrophoresis, molecules migrate through the gel under the influence of an electric field. When an electric current is applied, charged molecules such as DNA, RNA, or proteins move toward the electrode with the opposite charge. The gel acts as a molecular sieve, allowing smaller molecules to move faster than larger ones, thus achieving separation based on size and charge. The incorrect options, such as agar, diffusion, active transport, and osmosis, do not involve the electric field mechanism that is central to gel electrophoresis.

Q65. In carbohydrates, hydrogen and oxygen are present in the simple ratio of:

• A. 2:1✓
• B. 3:1
• C. 1:1
• D. 3:4
• E. 1:3

Explanation: Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen, commonly following the formula Cx(H2O)y. This reflects a 2:1 ratio of hydrogen to oxygen, similar to water. Option A is correct because it represents this fundamental characteristic of carbohydrates. Options B, C, D, and E are incorrect because they do not represent the standard 2:1 hydrogen to oxygen ratio found in carbohydrates.

Q66. Which of the pigments are common in both humans and plants?

• A. Carotenoids✓
• B. Fucoxanthin
• C. Xanthophyll
• D. Chlorophyll

Explanation: Carotenoids are found in both plants and human.In plants,carotenoids play a role in photosynthesis by absorbing light, while inhumans, they act as precursors to vitamin A and have antioxidant properties.

Q67. Two different gene pairs, located at different loci, all work for the same trait and express in an additive manner. This phenomenon is called:

• A. Codominance
• B. Polygenic inheritance✓
• C. Multiple alleles
• D. Incomplete dominance
• E. Epistasis

Explanation: Polygenic inheritance is a form of genetic inheritance where multiple genes (often located on different chromosomes) contribute to a single phenotype or trait. This results in a continuous range of phenotypic variation, rather than discrete categories.

Q68. Isolation of cellular components to determine their structure and chemical composition is:

• A. Cell fractionation✓
• B. Chromatography
• C. Microscopy
• D. Spectrometry
• E. Electrophoresis

Explanation: Cell fractionation is a laboratory technique used to separate different cellular components while preserving their function. It typically involves breaking open cells (lysis) and then using centrifugation to separate the cell contents based on size and density. This process allows researchers to isolate specific organelles, proteins, or other cellular structures for study and analysis.

Q69. The type of cancer common in young men between the ages of 15 and 34 that has a high cure rate with early treatment is:

• A. Skin cancer
• B. Lung cancer
• C. Blood cancer
• D. Lymph cancer
• E. Testicular cancer✓

Explanation: Testicular cancer primarily affects younger men, with the highest incidence occurring in those between the ages of 15 and 35.

Q70. This process inhibits the metabolism and growth of anaerobic microbes used for the treatment of gas gangrene.

• A. Desiccation
• B. Radiation
• C. Hyperbaric oxygen therapy✓
• D. High-pressure process
• E. Lyophilization

Explanation: Hyperbaric oxygen therapy (HBOT) involves breathing pure oxygen in a pressurised chamber. This therapy enhances oxygen delivery to tissues, promotes healing, and can treat conditions like decompression sickness, carbon monoxide poisoning, and certain infections. It may also be used for chronic wounds and other medical conditions, though its effectiveness can vary.

Q71. The branching network-like arrangement of cardiac muscles is called:

• A. Epimysium
• B. Syndesmosis
• C. Gomphosis
• D. Sarcolemma
• E. Syncytium✓

Explanation: A syncytium is a large cell-like structure formed by the fusion of multiple cells, resulting in a mass of cytoplasm with multiple nuclei. It occurs naturally in certain tissues, like muscle fibers, and in some viral infections, where infected cells merge. Syncytia play a role in both normal biological processes and some pathological conditions.

Q72. Molecules that bind to an enzyme away from the active site and increase the function of that active site are known as:

• A. Activation energy without enzyme
• B. Energy of reactants
• C. Activation energy with enzyme
• D. Energy of product
• E. Allosteric activators✓

Explanation: The correct answer is allosteric activators. These molecules bind to an enzyme at a location other than the active site, known as the allosteric site. This binding causes a conformational shift in the enzyme's structure that improves the accessibility or functionality of the active site, thus increasing the enzyme's catalytic efficiency.The other options relate to different concepts: 'Activation energy without enzyme' and 'Activation energy with enzyme' are about the energy barriers in reactions; 'Energy of reactants' and 'Energy of product' describe the energy states of substances in a reaction, not the modulation of enzyme activity.

Q73. The number of oxygen molecules that are transported by one hemoglobin molecule is:

• A. 1
• B. 4✓
• C. 3
• D. 2
• E. 5

Explanation: Hemoglobin is a protein found in red blood cells that has four heme groups, each capable of binding to one oxygen molecule. Thus, one hemoglobin molecule can transport a maximum of four oxygen molecules at a time. Options 1, 2, and 3 are incorrect as they suggest fewer binding sites than are available. Option 5 is incorrect as hemoglobin cannot bind more than four oxygen molecules.

Q74. The top milk-producing animal is:

• A. Nili-Ravi✓
• B. Bhadawari
• C. Godavari
• D. Blue-Ravi
• E. Jaffrabadi

Explanation: The Nili-Ravi is a breed of water buffalo recognised for its high milk yield, making it one of the top choices for dairy production, particularly in Pakistan and India. This breed's ability to produce large quantities of milk makes it highly prized among dairy farmers. Other options, such as the Bhadawari and Jaffrabadi, are also known for milk production but do not reach the same levels as the Nili-Ravi. The Godavari and Blue-Ravi are not established breeds known for high milk production.

Q75. Which one of the following is the precursor for the synthesis of testosterone, progesterone, and estrogens?

• A. Choline
• B. Cholesterol✓
• C. Oil
• D. Waxes
• E. Albumin

Explanation: Cholesterol serves as the building block for steroid hormones such as estrogen, testosterone, cortisol, and aldosterone, which are involved in processes like reproduction, stress response, and water balance.

Q76. A neural cable extending from the brain down through the backbone and enclosed in the vertebral column is called:

• A. Meninges
• B. Spinal cord✓
• C. Axon
• D. Brainstem
• E. Hindbrain

Explanation: The spinal cord is a long, cylindrical bundle of nerve fibers and supporting cells that extends from the brainstem (specifically the medulla oblongata) down through the vertebral column. It serves as the main communication pathway between the brain and the rest of the body. The spinal cord is a crucial component of the central nervous system (CNS), along with the brain, and it is protected by the vertebrae, the meninges, and cerebrospinal fluid (CSF).

Q77. Which of the following accurately describes Helicobacter pylori?

• A. Flagellated rod-shaped bacterium
• B. Flagellated chain bacterium
• C. Flagellated spiral-shaped bacterium✓
• D. Non-flagellated spiral-shaped bacterium
• E. Non-flagellated rod-shaped bacterium

Explanation: Helicobacter pylori is a flagellated spiral-shaped bacterium. Its spiral shape and flagella help it move through the mucus lining of the stomach, contributing to its pathogenicity. The other options are incorrect because they do not accurately describe both the flagellation and the spiral shape of H. pylori. Options describing it as rod-shaped or non-flagellated do not match its known scientific characteristics.

Q78. Water has a very high heat of vaporization, i.e.:

• A. 274 kcal/kg
• B. 374 kcal/kg
• C. 474 kcal/kg
• D. 574 kcal/kg✓
• E. 674 kcal/kg

Explanation: Water has a high heat of vaporization of 574 kcal/kg due to the extensive hydrogen bonding between its molecules. This property means that a significant amount of energy is needed to convert water from a liquid to a gas, impacting various biological processes such as temperature regulation in organisms. The other options are incorrect because they either underestimate or overestimate the energy required due to hydrogen bonding in water.

Q79. Which cells are responsible for the formation of cartilage?

• A. Neurosecretory cells
• B. Lymphocytes
• C. Osteocytes
• D. Leukocytes
• E. Chondrocytes✓

Explanation: Chondrocytes are the only cells found in healthy cartilage. They originate from chondroblasts and are responsible for producing and maintaining the cartilage matrix, which is made up of collagen and proteoglycans. Chondrocytes help maintain the structure and function of cartilage by regulating its repair and regeneration.

Q80. Behavioral responses are controlled by:

• A. Pituitary gland
• B. Cerebellum
• C. Thalamus
• D. Amygdala✓
• E. Hippocampus

Explanation: The correct answer is Amygdala because it plays a key role in processing emotions and controlling behavioral responses that are related to those emotions, particularly fear and aggression. The amygdala is involved in the emotional aspect of behavior, making it a key structure in behavioral control. In contrast, the Pituitary gland regulates hormones and bodily functions but does not directly manage behavioral responses. The Cerebellum is primarily focused on coordination and motor control, while the Thalamus serves as a sensory relay and is not directly associated with behavioral control. Lastly, the Hippocampus is important for memory formation, but it does not have an immediate role in controlling behaviors.

Q81. In skeletal muscles, which tube runs perpendicularly and is connected with the sarcoplasmic reticulum?

• A. Troponin
• B. T-tubules✓
• C. Monochondrion
• D. Myosin
• E. Actin

Explanation: T-tubules (transverse tubules) are invaginations of the cell membrane (sarcolemma) in muscle cells. They help transmit electrical impulses (action potentials) deep into the muscle fiber, ensuring that the signal for contraction reaches all parts of the muscle at the same time. This coordinated signaling triggers the release of calcium from the sarcoplasmic reticulum, which is essential for muscle contraction.

Q82. The active site of the enzyme is the region that:

• A. Binds with the product of catalytic reaction
• B. Is involved in catalytic reactions✓
• C. Is inhibited by coenzymes and cofactors
• D. Binds allosteric regulators of the enzyme
• E. Is inhibited by coenzymes only

Explanation: The active site of an enzyme is crucial because it is the region where substrates bind and undergo chemical transformation during a catalytic reaction. This is what makes Option B correct. The other options are incorrect because they either misunderstand the role of the active site or confuse it with other parts of the enzyme, such as allosteric sites or the role of cofactors and coenzymes. Coenzymes and cofactors often assist in the enzyme's function, rather than inhibit the active site, and allosteric regulators affect enzyme activity through different sites.

Q83. Frostbites are due to:

• A. Fluid retention
• B. Vasodilation
• C. Muscular expansion
• D. Vasoconstriction✓
• E. Vascular contraction

Explanation: Vasoconstriction is the narrowing of blood vessels, which reduces blood flow and increases blood pressure. It can occur in response to cold temperatures, stress, or certain hormones, helping to regulate blood distribution and maintain body temperature.

Q84. In which part of the brain are a set of neurosecretory cells found that exert control over the anterior pituitary gland by secreting, releasing, and inhibiting hormones?

• A. Pons
• B. Hypothalamus✓
• C. Hippocampus
• D. Amygdala
• E. Midbrain

Explanation: The hypothalamus is a small brain region that regulates essential bodily functions, including temperature, hunger, thirst, sleep-wake cycles, and emotional responses. It connects the nervous system to the endocrine system by controlling the pituitary gland, which releases hormones that influence various processes in the body.

Q85. It transports oxygen from the lungs to every tissue of the body.

• A. Hemoglobin✓
• B. Proteins
• C. Hormones
• D. Lipids
• E. Antibodies

Explanation: Hemoglobin is a protein found in red blood cells responsible for transporting oxygen from the lungs to the body's tissues and returning carbon dioxide from the tissues back to the lungs. It consists of four subunits, each containing an iron atom that binds to oxygen, giving blood its red color.

Q86. It is a condition of blindness where a person cannot distinguish blue color.

• A. Protanopia
• B. Monochromacy
• C. Dichromacy
• D. Deuteranopia
• E. Tritanopia✓

Explanation: Tritanopia is a rare form of color blindness where a person is unable to perceive blue light due to the absence or malfunction of blue cone cells. This causes difficulty distinguishing between blues and yellows, and often makes the world appear in shades of red, pink, green, and grey.

Q87. Chelate means:

• A. Bidentate
• B. lon
• C. Monodentate
• D. Crab claws✓
• E. Metal

Explanation: Chelates are sometimes metaphorically referred to as "crab claws" because of how they "grasp" a metal ion with multiple coordination sites, similar to how a crab uses its claws to hold onto something.

Q88. The shape of an ammonia molecule is:

• A. Angular
• B. Tetrahedral
• C. Linear
• D. Planar
• E. Pyramidal✓

Explanation: The shape of an ammonia (NH₃) molecule is trigonal pyramidal. This geometry arises because Nitrogen is at the center, bonded to three hydrogen atomst.It has one lone pair of electrons, which repels the bonded pairs, pushing the hydrogen atoms down into a pyramid shape.

Q89. It is used as a preservative and antibacterial agent in livestock feed:

• A. Butyric acid
• B. Formic acid✓
• C. Caroic acid
• D. Propionic acid
• E. Valeric acid

Explanation: **Formic acid** (HCOOH) is the simplest carboxylic acid with a pungent odor. It's found in ant and bee venom and is used in textiles, leather production, and as a preservative. It also has antibacterial properties.

Q90. The charge of an electron is:

• A. -1.602x10-19C✓
• B. 1.602x10-15C
• C. 1.602x10-2C
• D. 1.602x10-18C
• E. 1.602x10-1C

Explanation: The correct answer is Option A: -1.602x10-19C. This value is the recognized elementary charge representing the negative charge carried by an electron. The other options are incorrect as they either overestimate or underestimate this fundamental constant. Understanding the magnitude of elementary charge is crucial for solving problems related to atomic structure and electrostatics.

Q91. The equilibrium of this reaction would not be affected by an increase in pressure:

• A. 2SO2 + 02—-->2SO3
• B. N2 + 02 —---> 2NO✓
• C. 2NO + Cl —--› 2NOCI
• D. PCl5 → PCl3 + Cl2
• E. CO + 3H2 —--> CH4 + H20

Explanation: The correct answer is N₂ + O₂ → 2NO, because an increase in pressure doesn't affect the equilibrium since the number of gas molecules remains the same on both sides.

Q92. The density of benzene is:

• A. 0.80 g/cm³
• B. 0.88 g/cm³✓
• C. 0.85 g/cm³
• D. 0.82 g/cm³
• E. 0.08 g/cm³

Explanation: Benzene is a hydrocarbon with a density of approximately 0.879 g/cm³ at 20°C. This means it is less dense than water (1.00 g/cm³) and will float when placed in it. The closest option,0.88 g/cm³, accurately reflects this property. Other options either significantly underestimate or are slightly lower than the actual density of benzene.

Q93. According to Raoult's law, the relative lowering of vapor pressure is equal to:

• A. Mole fraction of solute✓
• B. Mole fraction of solvent
• C. Molarity
• D. Molality
• E. Parts per million

Explanation: In Raoult's Law, the lowering of vapor pressure of a solvent in a solution is directly related to the mole fraction of the solute.

Q94. When an unsymmetrical alkene undergoes addition reactions, the negative part of attacking reagent is added to that double-bonded carbon atom which contains:

• A. Highest number of chloride atoms
• B. Lesser number of hydrogen atoms✓
• C. Highest number of hydrogen atoms
• D. Moderate number of hydrogen atoms
• E. Lesser number of chloride atoms

Explanation: This is based on Markovnikov's Rule, which states that in the addition of a protic acid (such as HCl, HBr, etc.) to an unsymmetrical alkene, the hydrogen atom (the positive part of the reagent) attaches to the carbon with the greater number of hydrogen atoms, and the negative part (such as Cl⁻, Br⁻, etc.) attaches to the carbon with the fewer hydrogen atoms.

Q95. According to Charles, at 0º K (-273.15°C), the volume of a gas should be:

• A. -2
• B. Zero✓
• C. -1
• D. +2
• E. +1

Explanation: At 0 K (−273.15°C), the temperature is theoretically at absolute zero, where the kinetic energy of gas particles ceases. According to Charles's Law, which states that the volume of a gas is directly proportional to its temperature on the Kelvin scale, the volume would theoretically become zero as the temperature approaches absolute zero. This means the gas would occupy no space, as there would be no energy to maintain volume. Options suggesting negative or positive volumes are incorrect since they do not reflect the direct relationship outlined by Charles's Law.

Q96. The paramagnetic behavior of molecules such as oxygen molecules cannot be explained by:

• A. Molecular orbital theory
• B. Hybridization
• C. Valence bond theory✓
• D. Valence shell electron pair repulsion theory

Explanation: Molecular Orbital Theory (MOT): This theory accounts for paramagnetism by considering the arrangement of electrons in molecular orbitals, where unpaired electrons in these orbitals lead to paramagnetic properties.Valence Bond Theory (VBT): While VBT primarily focuses on the formation of bonds and hybridization, it can also address unpaired electrons in certain cases, indirectly linking to paramagnetism.Valence Shell Electron Pair Repulsion (VSEPR) Theory: This theory is primarily used to predict molecular shapes based on the repulsion between electron pairs. It does not consider the spin of electrons or their distribution in orbitals, and thus does not provide an explanation for paramagnetism.Hybridization: This concept can relate to paramagnetism when discussing the formation of bonds and the arrangement of unpaired electrons in hybrid orbitals.

Q97. The decomposition of H2O2 is inhibited by:

• A. MnO2
• B. Ethanol
• C. Glycerin✓
• D. V203
• E. Iron powder

Explanation: the decomposition of hydrogen peroxide is suppressed by adding glycerol to the solution of it. Thus, glycerine or glycerol acts as a negative catalyst

Q98. The bond length between C-C in benzene is:

• A. 1.34 Å
• B. 1.39 Å✓
• C. 1.56 Å
• D. 1.38 Å
• E. 1.46 Å

Explanation: Option B is correct because the bond length of C-C in benzene is approximately 1.39 Å. This is due to the delocalization of electrons across the ring, resulting in bond lengths that are neither purely single nor double bonds. Option A (1.34 Å) is too short, suggesting a double bond, which does not apply here. Option C (1.56 Å) is indicative of a single bond, which is also not the case. Option D (1.38 Å) is close, but slightly off the experimentally determined value. Option E (1.46 Å) is too long and does not fit the resonance hybrid model of benzene.

Q99. "In an orbital of an atom, no two electrons can have the same set of four quantum numbers; at least one quantum number must be different." This statement is:

• A. Aufbau principle
• B. Pauli's exclusion principle✓
• C. Hund's rule
• D. Wissewser rule
• E. Magnetic quantum number

Explanation: Pauli's exclusion principle states that no two fermions (such as electrons) can occupy the same quantum state simultaneously within an atom. This principle explains why electrons in an atom fill different orbitals and have distinct quantum numbers.

Q100. The IUPAC name of isopropyl alcohol is:

• A. 1-butanol
• B. 2-propanol✓
• C. 1-propanol
• D. 2-butanol
• E. propanol

Explanation: The correct IUPAC name for isopropyl alcohol is propan-2-ol. This name reflects the structure of the molecule: a three-carbon chain (propane) with a hydroxyl group (-OH) attached to the second carbon atom. The prefix 'iso-' in isopropyl indicates the branching at the second carbon, which aligns with the IUPAC naming as 'propan-2-ol'.Option A (1-butanol) and Option D (2-butanol) are incorrect because they describe four-carbon alcohols, not three. Option C (1-propanol) is incorrect because the hydroxyl group is on the first carbon, not the second. Option E (propanol) is too vague as it doesn't specify the position of the hydroxyl group.

Q101. The unit of rate constant for the first-order reaction is:

• A. conc.s-1
• B. M2s-1
• C. s-1✓
• D. M-1s-1
• E. M-1s-2

Explanation: The unit of the rate constant for a first-order reaction is s-1. This is because, for a first-order reaction, the rate is directly proportional to the concentration of one reactant, and the order of the reaction dictates the units of the rate constant. For a first-order reaction, the units of the rate (M s-1) divided by the concentration (M) give the rate constant units of s-1. Other options, like M2s-1 and M-1s-1, correspond to higher-order reactions or are not applicable to standard reaction orders.

Q102. Volume is a:

• A. Intensive property
• B. Entropy
• C. Path function
• D. Isolated system
• E. State function✓

Explanation: A state function is a property of a system that depends only on its current state, rather than the path taken to reach that state. This means that the value of a state function is determined solely by the state of the system at a given moment, regardless of how the system arrived at that state.

Q103. Collection of gas over water is an example of:

• A. Boyle's law
• B. Avogadro's law
• C. Dalton's law✓
• D. Graham's law
• E. Gay-Lussac law

Explanation: Dalton's Law states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of each individual gas. When collecting gases over water, the total pressure of the gas collected is the sum of the partial pressure of the gas and the vapor pressure of the water at that temperature. For instance, if the vapor pressure of water at a certain temperature is 20 mmHg and the measured total pressure is 740 mmHg, the partial pressure of the gas collected can be found by subtracting the vapor pressure

Q104. Dry ice is an example of:

• A. Molecular solid✓
• B. Metallic solid
• C. Covalent solid
• D. Ionic solid
• E. Plastic

Explanation: In dry ice, the CO₂ molecules are held together in the solid by weak intermolecular forces (not by strong covalent or ionic bonds).Because of these weak forces, dry ice sublimates easily at −78.5°C instead of melting into a liquid under normal atmospheric pressure.

Q105. A low atmospheric pressure system is called:

• A. Diffusion
• B. Depression✓
• C. Effusion
• D. Contraction
• E. Cooling

Explanation: In the context of atmospheric pressure, depression typically refers to the decrease in pressure experienced in specific situations, such as weather phenomena or within a closed system.

Q106. The pH value of human blood is:

• A. 7.80
• B. 7.35✓
• C. 7.33
• D. 6.62
• E. 7.05

Explanation: The pH of human blood is typically maintained between 7.35 and 7.45. This range is slightly basic, as a pH of 7 is considered neutral. The body has several mechanisms to regulate blood pH tightly, including the bicarbonate buffer system. Option B, 7.35, falls within this normal range. Option A, 7.80, is too alkaline for blood, whereas Options C, D, and E (7.33, 6.62, 7.05) are too acidic, indicating varying degrees of acidosis.

Q107. It is used to distinguish between primary, secondary, and tertiary alcohol:

• A. Tollens Reagent
• B. Grignard Reagent
• C. Benedict Reagent
• D. Bloor Reagent
• E. Lucas Reagent✓

Explanation: Lucas reagent, a mixture of concentrated hydrochloric acid (HCl) and zinc chloride (ZnCl₂), is primarily used to distinguish between primary, secondary, and tertiary alcohols through a process known as the Lucas test. When an alcohol is treated with Lucas reagent, the reaction proceeds via the formation of an alkyl chloride. Tertiary alcohols react rapidly, often within minutes, to form insoluble alkyl chlorides, leading to an immediate cloudiness. Secondary alcohols take longer, while primary alcohols react very slowly, if at all, under these conditions. This differential reactivity helps in identifying the alcohol type based on the time taken for the reaction to occur.

Q108. An example of an endothermic reaction is:

• A. Photosynthesis✓
• B. Synthesis of NH3
• C. Nuclear fission
• D. Oxidation of sulfur gases
• E. Burning of fuel and coal

Explanation: Photosynthesis is an endothermic process. During photosynthesis, plants absorb light energy from the sun and convert it into chemical energy by synthesizing glucose from carbon dioxide and water.

Q109. Stoichiometry is the study of _relationship between reactants and products in a chemical reaction by using a balanced chemical equation:

• A. Quantitative✓
• B. Qualitative
• C. Chemical
• D. Descriptive
• E. Physical

Explanation: The correct answer is Option A: Quantitative. Stoichiometry is fundamentally about the quantitative relationships between reactants and products in chemical reactions, using balanced equations to determine the amounts involved. Option B (Qualitative) is incorrect because it deals with non-numeric properties. Option C (Chemical) is too broad, as it does not capture the quantitative nature. Option D (Descriptive) focuses on explanations rather than calculations. Option E (Physical) relates to physical properties, not the quantity-focused aspect of stoichiometry.

Q110. Ketones, when treated with LiAlH4, reduce to:

• A. Primary alcohol
• B. Tertiary alcohol
• C. Alcohol
• D. Dihydric alcohol
• E. Secondary alcohol✓

Explanation: Ketones reduce to form secondary alcohols in the presence of lithium aluminum hydride (LiAlH₄). LiAlH₄ is a strong reducing agent that donates hydride ions (H⁻) to the carbonyl carbon of the ketone, resulting in the formation of the corresponding alcohol. For example, if you reduce a ketone like acetone (2-propanone), it will be converted to isopropanol (2-propanol).

Q111. The term "active mass" used in the Law of Mass Action means:

• A. Number of moles per dm2
• B. Number of moles per dm3✓
• C. Gram per dm'
• D. Number of moles
• E. Number of molecules

Explanation: The term "active mass" in the Law of Mass Action refers to the concentration of a substance involved in a chemical reaction, usually expressed in moles per decimetercube (mol/dm3) for solutions or partial pressure for gases. The Law of Mass Action states that the rate of a chemical reaction is directly proportional to the product of the active masses (concentrations) of the reactants, each raised to the power of their respective stoichiometric coefficients in the balanced chemical equation.

Q112. The neutron was discovered by:

• A. Max Planck
• B. Neil Bohr
• C. J.J. Thomson
• D. Goldstein
• E. James Chadwick✓

Explanation: James Chadwick is best known for his discovery of the neutron in 1932, a breakthrough that significantly advanced our understanding of atomic structure.

Q113. When chlorobenzene reacts with sodium hydroxide at 350°C and 150 atmospheric pressure, it gives rise to the formation of:

• A. Sodium chromate
• B. Phenol
• C. Sodium phenoxide✓
• D. Sodium sulfate
• E. Phenoxide

Explanation: When chlorobenzene (C₆H₅Cl) reacts with sodium hydroxide (NaOH) at 350°C and 150 atmospheric pressure, it undergoes a nucleophilic substitution reaction known as the Dow process, resulting in the formation of sodium phenoxide (C₆H₅ONa). The reaction benefits from the high temperature and pressure, which facilitate the substitution of the chlorine atom with a hydroxide ion. Sodium phenoxide can later be acidified to produce phenol (C₆H₅OH). Other options, such as sodium chromate and sodium sulfate, are incorrect as they are not products of this reaction. Phenol is formed only after further processing of sodium phenoxide, and phenoxide alone does not specify the sodium salt form.

Q114. The carboxylic acid is stronger than:

• A. PCl3
• B. H2SO4
• C. HNO3
• D. HCI
• E. СН3ОН✓

Explanation: Methanol is a very weak acid with a much higher pKa (around 15.5) compared to carboxylic acids (pKa around 4-5). Carboxylic acids, like acetic acid, are much stronger due to their ability to stabilize the negative charge on the conjugate base (carboxylate anion) through resonance.

Q115. The initial discovery of natural gas in Pakistan dates back to _ when it was found in the Sui area of Baluchistan:

• A. 1955
• B. 1954
• C. 1956
• D. 1952✓
• E. 1992

Explanation: The discovery of natural gas in the Sui area of Balochistan in 1952 was a landmark event in Pakistan's history, initiating the development of its natural energy resources. This discovery was crucial for the country's energy infrastructure. Options 1955, 1954, and 1956 are incorrect because they do not align with the actual year of discovery, and 1992 is far too late, occurring decades after the initial event.

Q116. Reduction of aldehydes & ketones by Zn-Hg amalgam and concentrated HCl results in conversion to an alkane. This reaction is known as:

• A. Down Reduction
• B. Cope Reduction
• C. Wolff-Kishner Reduction
• D. Clemmensen reduction✓
• E. Sodium tetrahydroboride

Explanation: Clemmensen reduction is a chemical reaction used to convert carbonyl compounds (such as aldehydes and ketones) into alkanes. This reduction is typically carried out using zinc amalgam (Zn/Hg) in the presence of hydrochloric acid (HCl).

Q117. Deficiency causes loss of weight, appetite, and taste.

• A. K
• B. P
• C. Fe
• D. Zn✓

Explanation: Zinc plays a crucial role in the functioning of taste and smell receptors. A deficiency can result in altered taste perception (dysgeusia) or a diminished sense of smell (hyposmia), making food less appealing. zinc deficiency can lead to loss of appetite. This symptom is part of a broader range of effects that zinc deficiency can have on the body.

Q118. The rate of SN1 mechanism depends upon:

• A. Concentration of nucleophile
• B. Concentration of both substrate and nucleophile
• C. Polar non-polar solvent
• D. Concentration of substrate only✓
• E. Concentration of reactant

Explanation: The rate of an S_N1 reaction (unimolecular nucleophilic substitution) depends solely on the concentration of the substrate (the molecule undergoing substitution). This is because the rate-determining step is the formation of the carbocation after the leaving group departs. Once the carbocation is formed, the nucleophile can quickly react with it.

Q119. The total number of alpha amino acids is:

• A. 19
• B. 27
• C. 22✓
• D. 25
• E. 28

Explanation: The correct answer is 22. This includes the 20 standard amino acids that are the building blocks of proteins, plus 2 special amino acids: selenocysteine and pyrrolysine, which are incorporated into proteins in specific circumstances. Options such as 19, 25, 27, and 28 either underestimate or overestimate this total, not accounting properly for these additional amino acids.

Q120. Which statement about tautomerism is correct?

• A. Only occurs in organic compounds
• B. Not influenced by temperature
• C. Have same molecular formula✓
• D. Have different molecular formula
• E. Identical chemical properties

Explanation: Tautomers are a specific type of isomerism characterized by having the same molecular formula but differing in the connectivity of atoms, specifically the position of a proton and a double bond. This means that while they share the same chemical composition, their structural differences can lead to variations in their chemical behavior and properties.Option A is incorrect as tautomerism is not limited to organic compounds alone. Option B is incorrect because temperature can influence the equilibrium between tautomers. Option D is wrong since tautomers must have the same molecular formula, and Option E is misleading as tautomers can exhibit different chemical properties despite having similar structures.

Q121. Aldehydes & ketones can be converted to alkane. This reaction is called:

• A. Ozonolysis
• B. Wolff-Kishner reaction✓
• C. Grignard reaction
• D. Friedel-Craft reaction
• E. None of these

Explanation: The Wolff-Kishner reaction is a chemical reaction used to reduce aldehydes or ketones to alkanes. This reaction involves the treatment of the carbonyl compound with hydrazine (NH₂NH₂) in the presence of a strong base (like potassium hydroxide, KOH) and heat. During the reaction, the carbonyl group (C=O) is converted into a methylene group (CH₂), effectively removing the oxygen atom. The reaction is performed under strongly basic conditions and is often used when acidic conditions are not suitable, unlike the Clemmensen reduction.

Q122. An example of a bidentate ligand among the following is:

• A. Br
• B. CN-
• C. C204-✓
• D. OH-
• E. CI

Explanation: Oxalate ion (C₂O₄²⁻): Bidentate ligand, anionic, coordinates through both oxygen atoms, forming chelate complexes with metal ions.

Q123. A fuel cell is a typical galvanic cell that is based on a reaction between:

• A. Hydrogen and copper
• B. Methane and oxygen
• C. Hydrogen and oxygen✓
• D. Nitrogen and oxygen
• E. Hydrogen and zinc

Explanation: Hydrogen and oxygen: This is the reaction in a hydrogen fuel cell, where hydrogen (H₂) reacts with oxygen (O₂) to produce electricity, water, and heat.

Q124. The alkali metal that gives a yellow color during a flame test is:

• A. Ba
• B. Na✓
• C. K
• D. Cs
• E. Li

Explanation: Sodium (Na), an alkali metal from Group 1, gives a bright yellow flame during a flame test. The yellow color comes from the excitation of sodium atoms, particularly due to the sodium D-line emission at wavelengths around 589 nm. When sodium ions are heated in a flame, their electrons get excited to higher energy levels and then fall back to lower levels, releasing energy as visible yellow light. This test is so sensitive that even trace amounts of sodium can make the flame appear yellow.

Q125. Which of the following possesses the weakest London dispersion forces?

• A. F2
• B. Br2
• C. Cl2
• D. I2
• E. He✓

Explanation: The correct answer is Option E: He. Helium is a noble gas characterized by its minimal atomic size and the lowest number of electrons among the options provided. This results in the weakest London dispersion forces. In comparison, F2 has more electrons than He, giving it stronger dispersion forces. Cl2 and Br2 are larger and have more electrons, further increasing their dispersion forces relative to He. I2 is the largest and heaviest, possessing the strongest dispersion forces of all.

Q126. Which of the following liquids shows maximum surface tension?

• A. Water
• B. Mercury✓
• C. Ethyl alcohol
• D. Chloroform
• E. Benzene

Explanation: The correct answer is Mercury (Option B). Mercury has the highest surface tension because of the strong cohesive forces between its metal atoms, which are much stronger than the hydrogen bonds in water or the van der Waals forces in other liquids like benzene, chloroform, and ethyl alcohol. While water has significant surface tension due to hydrogen bonding, it is still less than mercury. Ethyl alcohol and chloroform have even lower surface tensions due to weaker intermolecular forces, and benzene, with its weak van der Waals forces, has the lowest surface tension among the given options.

Q127. Hydroquinone is a phenol; it contains two OH groups at:

• A. Position 1 and 2
• B. Position 1 and 3
• C. Position 1 and 4✓
• D. Position 2 and 3

Explanation: The correct answer is Option C: Position 1 and 4. Hydroquinone is a type of phenol where the two hydroxyl (OH) groups are positioned opposite each other on a benzene ring, specifically at the 1 and 4 positions. This gives hydroquinone its distinct para configuration. Option A describes catechol, where the OH groups are adjacent. Option B refers to hydroxyquinone, where the OH groups are separated by one carbon. Option D describes resorcinol, which also has a separation by one carbon but at different positions than hydroquinone.

Q128. Generally, actual yield is:

• A. Less than theoretical yield✓
• B. Equal to the theoretical yield
• C. Greater than theoretical yield
• D. Greater than percent yield

Explanation: The correct answer is Option A: Less than theoretical yield. In most real-world chemical reactions, the actual yield is less than the theoretical yield due to factors such as incomplete reactions, side reactions, and material losses during processing. Option B, 'Equal to the theoretical yield,' is incorrect because this scenario is rare and assumes perfect efficiency. Option C, 'Greater than theoretical yield,' is incorrect as the theoretical yield is the maximum possible yield. Option D, 'Greater than percent yield,' is also incorrect because percent yield is a percentage that cannot exceed 100%, and actual yield cannot exceed the theoretical yield.

Q129. Formic acid is naturally found in:

• A. Butter
• B. Goat
• C. Milk
• D. Vinegar
• E. Ants✓

Explanation: Ants produce formic acid.

Q130. Urea was first synthesized by Wohler from an inorganic material named:

• A. Ammonium bicarbonate
• B. Ammonium nitrate
• C. Ammonium oxalate
• D. Ammonium cyanate✓
• E. Ammonium chloride

Explanation: Urea was synthesized by Friedrich Wöhler in 1828 using ammonium cyanate. This synthesis was significant because it demonstrated that organic compounds could be created from inorganic materials, which contradicted the prevailing belief in 'vitalism' — the idea that organic compounds could only be produced by living organisms. The other options, such as ammonium bicarbonate, ammonium nitrate, ammonium oxalate, and ammonium chloride, were not involved in Wöhler's synthesis of urea.

Q131. Oil of Vitriol refers to:

• A. Caustic soda
• B. Alum
• C. Borax
• D. Sulfuric acid✓
• E. Nitric acid

Explanation: The correct answer is Sulfuric acid (Option D). Historically, sulfuric acid was called 'oil of vitriol' because it was produced by roasting iron sulfate (vitriol) and has an oily consistency. The other options are not connected to the term 'vitriol':Caustic soda (Option A) is an alkaline substance and not an acid.Alum (Option B) is a compound of aluminum and not an acid.Borax (Option C) is a boron compound also unrelated to acids.Nitric acid (Option E) is another type of acid but not referred to as 'oil of vitriol'.

Q132. The number of five-membered and six-membered rings in Buckyball is, respectively:

• A. 40 and 20
• B. 12 and 12
• C. 5 and 15
• D. 5 and 10
• E. 12 and 20✓

Explanation: The Buckyball, or C₆₀ fullerene, is a molecular structure composed of 60 carbon atoms arranged in a pattern similar to a soccer ball. This configuration includes 12 pentagonal (five-membered) rings and 20 hexagonal (six-membered) rings. The pentagons are crucial for the curvature of the spherical shape. Option E is correct because it accurately represents this structural composition. Other options either overestimate or underestimate the number of rings, failing to match the known structure of a Buckyball.

Q133. It is an example of a crystalline solid:

• A. Plastics
• B. Charcoal
• C. Glass
• D. Alum✓
• E. Rubber

Explanation: Alum is a crystalline solid that typically forms in well-defined geometric shapes, often octahedral. It is a type of double salt, usually consisting of potassium aluminum sulfate (KAl(SO₄)₂·12H₂O) or sodium aluminum sulfate, and is known for its solubility in water. Alums are commonly used in water purification, as a mordant in dyeing processes, and in various food applications, such as pickling.

Q134. The structure of primary amines is:

• A. Trigonal
• B. Tetrahedral pyramidal✓
• C. Planar
• D. Linear
• E. Regular tetrahedral

Explanation: Tetrahedral pyramidal molecular shape, often referred to as trigonal pyramidal, occurs when a central atom is bonded to three other atoms and has one lone pair of electrons, resulting in a three-dimensional shape with bond angles of approximately 107 degrees

Q135. Mostly p-block elements react with-----each other to form binary compounds:

• A. Oxygen
• B. Water
• C. Halogens✓
• D. Nitrogen
• E. Hydrogen

Explanation: Option C is correct. P-block elements primarily react with halogens to form binary compounds, such as halides. These elements can also react with hydrogen to form compounds like hydrides, but the most common reactivity for forming straightforward binary compounds is indeed with halogens.

Q136. The maximum number of electrons in a given subshell is calculated by:

• A. n2
• B. 2(n+1)
• C. 2n2
• D. 2(2l+1)✓
• E. 2+1

Explanation: 2(2l + 1) is the correct formula for the maximum number of electrons in a subshell, as it accounts for the number of orbitals (2l + 1) in a subshell, with each orbital able to hold 2 electrons.

Q137. Which shape/geometry is found in AX2 when the bond angle is 180°?

• A. Pyramidal
• B. Bent
• C. Triangle
• D. Tetrahedral
• E. Linear✓

Explanation: Linear molecular shape occurs when atoms are arranged in a straight line, typically resulting from two atoms bonded with no lone pairs on the central atom, leading to a bond angle of 180 degrees.

Q138. A colloidal solution of liquid into liquid is known as:

• A. Solid foam
• B. Foam
• C. Fog
• D. Emulsion✓

Explanation: An emulsion is a stable mixture of two immiscible liquids, typically oil and water, where one liquid is dispersed in the other in the form of small droplets. Emulsions are commonly stabilized by emulsifiers, which are substances that reduce the surface tension between the two liquids, preventing them from separating. They are classified into two main types: oil-in-water (O/W) emulsions, where oil droplets are dispersed in water, and water-in-oil (W/O) emulsions, where water droplets are dispersed in oil. Emulsions are widely used in various industries, including food (e.g., mayonnaise), cosmetics (e.g., lotions), and pharmaceuticals, due to their ability to improve texture, stability, and delivery of active ingredients.

Q139. These hydrocarbons contain one or more double or triple bonds between the two adjacent carbon atoms in their structure:

• A. Alkenes and alcohol
• B. Alkenes and cycloalkanes
• C. Alkanes and alkyl halides
• D. Alkenes and alkynes✓
• E. Alkanes and alkenes

Explanation: Alkenes are unsaturated hydrocarbons characterized by at least one carbon-carbon double bond (C=C) and have the general formula CₙH₂ₙ. They are more reactive than alkanes due to the presence of the double bond, allowing for various chemical reactions such as addition reactions. In contrast, alkynes are also unsaturated hydrocarbons but contain at least one carbon-carbon triple bond (C≡C), with the general formula CₙH₂ₙ₋₂. Alkynes are even more reactive than alkenes, making them useful in a variety of chemical synthesis processes. Both alkenes and alkynes are essential in organic chemistry, serving as key intermediates and building blocks for more complex organic compounds.

Q140. The conjugated acid of NH3 is:

• A. NH4+✓
• B. NH
• C. NH2
• D. NH2-
• E. NH3

Explanation: NH₄⁺: This is the conjugated acid of NH₃ (ammonia). When NH₃ accepts a proton (H⁺), it forms NH₄⁺.

Q141. The linear momentum of a photon is given as:

• A. me
• B. mv
• C. me²
• D. moc²
• E. hv/c✓

Explanation: hv/c: This is the correct formula for the linear momentum of a photon, where h is Planck's constant, v is the frequency of the photon, and c is the speed of light.

Q142. The unit of resistance is:

• A. Volt
• B. Watt
• C. Coulomb
• D. Ohm✓
• E. Ampere

Explanation: Resistance is measured in ohms.

Q143. Longitudinal waves do not exhibit:

• A. Refleetion
• B. Diffraction
• C. Polarization✓
• D. Interference
• E. Refraction

Explanation: Polarization refers to the orientation of the oscillations of a wave, typically applied to electromagnetic waves like light. In an unpolarized wave, the oscillations occur in all directions perpendicular to the direction of wave propagation. When a wave is polarized, its oscillations are confined to a specific direction.

Q144. One kilogram of mass is effectively converted into energy. The amount of energy will be:

• A. 9x10^16 J✓
• B. 3x10^10 J
• C. 9x10^-16 eV
• D. 9x10^6 J
• E. 9x10^15 eV

Explanation: The energy conversion from mass to energy can be calculated using Einstein's equation E=mc2, where E is the energy, m is the mass, and c is the speed of light in a vacuum (3x108 m/s). For a mass of 1 kilogram, E = 1 kg × (3x108 m/s)2 = 9x1016 J. This calculation confirms that the correct energy amount is 9x1016 Joules.Options B, C, D, and E are incorrect as they fail to accurately apply this calculation or use inappropriate units like electronvolts (eV) for expressing the result.

Q145. The unit of resistivity is:

• A. Ohm m✓
• B. Ampere
• C. Volt
• D. Watt
• E. Ohm

Explanation: The unit of resistivity is ohm meter.

Q146. The SI unit of power is:

• A. Ampere
• B. Coulomb
• C. Ohm
• D. Watt✓
• E. Joule

Explanation: Power is measured in Watts.

Q147. Total potential difference across the combination of three similar cells becomes maximum when:

• A. Two cells are connected in series and the third cell in parallel with the combination
• B. All three cells are connected in parallel
• C. Two cells are connected in parallel and the third cell in series with the combination
• D. The load connected to the combination is minimum
• E. All three cells are connected in series✓

Explanation: The potential difference is maximum across a circuit if cells are connected in series.

Q148. Which one of the following is correct for a transformer?

• A. Transformer converts DC into AC
• B. Transformer converts mechanical energy into electrical energy
• C. Transformer works on the principle of mutual induction✓
• D. Transformer converts AC into DC
• E. Transformer converts electrical energy into mechanical energy

Explanation: Transformers work on the principle of electromagnetic induction to change the voltage level in an AC circuit.

Q149. The time rate of change of linear momentum is equal to:

• A. Moment of force
• B. Force✓
• C. Angular momentum
• D. Torque
• E. Moment

Explanation: The rate of change of momentum (delta P) in unit time t is equal to force.

Q150. In projectile motion, the horizontal component of acceleration is:

• A. Zero✓
• B. 9.8m/s²
• C. 19.6m/s
• D. 4.9m/s²

Explanation: In projectile motion, the horizontal component of acceleration is zero. This is because no external force acts horizontally (assuming air resistance is negligible), so the horizontal velocity remains constant throughout the motion. The only acceleration is the vertical component, which is due to gravity.

Q151. Which of the following statements correct?

• A. Work can never be converted into heat.
• B. Work can be converted completely into heat.
• C. Both heat and work are interconvertible.✓
• D. Heat can never be converted into work.
• E. Heat can be converted completely into work.

Explanation: Yes, heat and work are interconvertible forms of energy. In thermodynamics, they can be transformed into each other.

Q152. The force responsible for the simple harmonic motion of a simple pendulum is:

• A. mg cosθ
• B. mg tanθ
• C. mg2 sinθ
• D. mg sinθ✓

Explanation: The force responsible for the simple harmonic motion of a simple pendulum is the component of gravitational force that acts along the arc of the pendulum's swing. This is given by mg sinθ, where mg is the weight of the pendulum bob and θ is the angle from the vertical. This force acts to restore the pendulum to its equilibrium position, hence it is known as the restoring force.Option A (mg cosθ) represents the component of gravitational force that acts perpendicular to the motion and does not contribute to the restoring motion. Option B (mg tanθ) is not a standard expression related to pendulum motion. Option C (mg2 sinθ) incorrectly suggests a squared force term, which is not applicable here.

Q153. "The current through a conductor is directly proportional to the potential difference between the ends of the conductor, provided that physical conditions remain the same." This is:

• A. Laplace's Law
• B. Ohm's Law✓
• C. Coulomb's Law
• D. Charles's Law
• E. Boyle's Law

Explanation: Ohm's Law states that the current through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance.

Q154. The measure of energy between any two points on a circuit is:

• A. Resistance
• B. Electromotive force
• C. Internal resistance
• D. Resistivity
• E. Potentíal difference✓

Explanation: Potential difference, often referred to as voltage, is the difference in electric potential between two points in an electric field. It represents the work done per unit charge to move a charge between those two points.

Q155. If electronic transitions in the hydrogen atom terminate in the second orbit, the emitted series is known as:

• A. Brackett series
• B. Paschen series
• C. Lyman series
• D. Balmer series✓
• E. Pfund series

Explanation: The Balmer series is a set of spectral lines in the hydrogen emission spectrum corresponding to electron transitions from higher energy levels to the n=2 energy level. These transitions result in the emission of visible light, making the Balmer series one of the most well-known series in atomic spectroscopy.

Q156. The force experienced by a current-carrying conductor placed in a magnetic field is:

• A. F = qBLθθ.
• B. F = BL sin θ.
• C. F = qvB sin θ
• D. F BL cos θ
• E. F = BIL sin θ✓

Explanation: The force experienced by a current-carrying conductor placed in a magnetic field is given by the formula F = BIL sin 0.

Q157. The ratio of'molar gas constant' to 'Avogadro's number' (R/Na) is called:

• A. Stefan's constant
• B. Boltzmann constant✓
• C. Rydberg's constant
• D. Coulomb's constant
• E. Planck's constant

Explanation: The ratio of the molar gas constant to Avogadro's number is called the Boltzmann constant .

Q158. "The electric force between two static point charges varies directly to the product of charges with each charge and inversely with the square of the distance between them." This is:

• A. Gay-Lussac's Law
• B. Coulomb's Law✓
• C. Faraday's Law
• D. Charles's Law
• E. Boyle's Law

Explanation: "The electric force between two static point charges varies directly to the product of charges with each charge and inversely with the square of the distance between them."

Q159. In radioactivity, the product of half-life T1/2 and decay constant (4) is equal to:

• A. 0.693✓
• B. 0.396
• C. 0.953
• D. 0.963
• E. 0.369

Explanation: In radioactivity, the product of half-life Tız and decay constant (4) is equal to 0.693.

Q160. The change in potential energy per unit charge between two points in an electric field is:

• A. Retentivity
• B. Potential difference✓
• C. Intensity
• D. Permittivity
• E. Permeability

Explanation: Potential difference, also known as voltage, is the difference in electric potential energy between two points in an electric field. It represents the work needed to move a unit charge from one point to another and is a measure of the driving force that pushes electric charges through a circuit.

Q161. Which of the following statements is correct?

• A. A magnetic field exerts a force if the charged particle moves opposite to the magnetic field.
• B. A magnetic field never exerts a force on a charged particle.
• C. A magnetic field exerts a force if the charged particle moves parallel to the magnetic field.
• D. A magnetic field exerts a force if the charged particle moves perpendicular to the magnetic field.✓

Explanation: A magnetic field exerts a force if the charge particle moves perpendicular to the magnetic field. This force is called Lorentz Force.

Q162. Resistivity depends on:

• A. Weight of material
• B. Charge of material
• C. Shape of material
• D. Size of material
• E. Temperature of material✓

Explanation: The resistivity of a material depends upon its temperature.

Q163. The speed of electromagnetic waves 'e' in free space is:

• A. c=3 x 108 m/s✓
• B. c =3 x 106 m/s
• C. c=3 x 10° m/s
• D. c=3 x 10 m/s

Q164. The constant power output of a machine is 6 W. The energy delivered by it in 2 minutes is:

• A. 12 joules
• B. 720 joules✓
• C. 72 joules
• D. 3 joules
• E. 120 joules

Q165. The process in which all the supplied heat is converted into work is called:

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

Explanation: The process in which all the supplied heat is converted into work is called a reversible isothermal process. However, it's important to note that in real-world scenarios, achieving 100% conversion of heat into work is impossible due to the Second Law of Thermodynamics, which states that some energy will always be lost as waste heat.

Q166. The charge-to-mass ratio (e/m) of an electron is:

• A. 9 x 10^4 C/kg
• B. 1.76 x 10° C/kg
• C. 1.76 x 1011 C/kg✓
• D. 1.602 x 10 C/kg
• E. 1.602 x 1011 C/kg

Explanation: The charge to mass ratio (e/m) of an electron is:1.76 x 10^11 C/kg.

Q167. If the instantaneous velocity of a body is equal to the average velocity, then:

• A. The body moves with decreasing velocity
• B. The body moves with variable acceleration
• C. The body moves with uniform velocity✓
• D. The body moves with uniform acceleration
• E. The body moves with increasing velocity

Explanation: If the instantaneous velocity is equal to average velocity then the body is moving with uniform velocity.

Q168. The waves that require medium for their propagation are known as:

• A. Electromagnetic waves
• B. De Broglie waves
• C. Mechanical waves✓
• D. Particle waves
• E. Matter waves

Explanation: Mechanical waves are waves that require a medium (solid, liquid, or gas) to propagate. They transfer energy through the vibration of particles in the medium.

Q169. The SI unit of the electric field is:

• A. JC-2
• B. N C-I✓
• C. Nm² C-1
• D. CN2
• E. Nm² C-2

Explanation: The SI unit of electric field is N C-I

Q170. An electron and proton enter a magnetic field perpendicularly with the same momentum:

• A. They move undeflected in opposite directions
• B. The electron deflects more than the proton
• C. They will deflect equally✓
• D. The proton deflects more than the electron.
• E. They will not deflect at all

Explanation: When an electron and a proton enter a magnetic field perpendicularly with the same momentum, they experience the Lorentz force, which is given by F = q(v × B), where q is the charge, v is the velocity, and B is the magnetic field. Since both the electron and proton have the same momentum, they will deflect equally in the magnetic field, regardless of their mass differences. The charge of the electron is negative, and the charge of the proton is positive, but since they are both moving in the same perpendicular field, the direction of their deflections will be opposite, but the magnitude will be the same. Thus, the correct answer is that they will deflect equally.Option A is incorrect because they cannot move undeflected when entering a magnetic field perpendicularly. Option B is misleading as it suggests that the deflection depends solely on mass; they deflect equally with the same momentum. Option D is incorrect because the proton's greater mass results in a smaller deflection for the same momentum. Option E is also incorrect since both particles will deflect.

Q171. A body starts from rest and falls freely under gravity; the distance covered by it in t' seconds is:

• A. 0.5gt^2✓
• B. gt
• C. 0.5g
• D. g

Explanation: The distance s covered by a body falling freely under gravity in t seconds, starting from rest, is given by the equation:s=1/2gt2

Q172. The total energy E of a body at any instant, executing simple harmonic motion, is:

• A. E =-2kx
• B. E=0.5(kx^2)✓
• C. E= -kx²
• D. E = kx

Explanation: The total energy E of a body at any instant, executing simple harmonic motion, is given by E=0.5(kx^2).

Q173. A reverse-biased semiconductor diode acts as:

• A. Rectifier
• B. On switch
• C. Inverter
• D. Off switch✓
• E. Amplifier

Explanation: A reverse-biased semiconductor diode can be thought of as an off switch because it prevents current from flowing through the circuit, similar to an open switch. Only a very small leakage current passes through until the breakdown voltage is exceeded.

Q174. For maximum work done by a constant force, the angle between force and displacement is:

• A. 45°
• B. 90°
• C. 65°
• D. 145°
• E. 0°✓

Explanation: Work done is given as F.dcosθ. cosθ is maximum at 0 degrees i.e 1.

Q175. A body is moving in a circle with constant speed. Which of the following statements is true?

• A. There is a force acting on the body at a tangent to the circle
• B. There is a force acting on the body toward the center of the circle✓
• C. There is no acceleration in the body
• D. There is a force acting on the body away from the center of the circle
• E. The net force acting on the body is zero

Explanation: When a body is moving in a circle a centripital force acts on it and although its speed remains constant it has a centripital acceleration as well.

Q176. The unit of potential difference is:

• A. Ampere
• B. Coulomb
• C. Volt✓
• D. Watt
• E. Ohm

Explanation: The volt measures electric potential difference or voltage.

Q177. In the SI system, the specific heat capacity is measured in:

• A. J kg^-1 K^-1✓
• B. J Kg
• C. J kg-1 C
• D. Jg-1 C-1

Explanation: The SI unit of specific heat capacity is J kg^-1 K^-1.

Q178. The period of uniform circular motion is given as:

• A. T = w/2r
• B. T = 2π/ w✓
• C. T=2n o
• D. T = 2rT
• E. T = 2π w²

Explanation: The time period in uniform circular motion is the time taken to complete one full revolution around the circular path and is given by the formula T= 2n/w.

Q179. In the mathematical relationship Φ = hv, the symbol Φ represents:

• A. Magnetic flux
• B. Threshold frequency
• C. Work function✓
• D. Electric flux
• E. Wave function

Explanation: The symbol Φ in the equation Φ = hv represents the work function, which is the minimum energy required to remove an electron from the surface of a material. In the context of the photoelectric effect, this energy is provided by photons with energy hv, where h is Planck's constant and v is the frequency of the photon. The other options are incorrect as they pertain to different physical concepts: magnetic flux and electric flux relate to field lines through a surface, threshold frequency is the minimum frequency for the photoelectric effect but not represented by Φ, and the wave function is a concept from quantum mechanics describing the state of a system.

Q180. The unit of current is:

• A. Volt
• B. Ohm
• C. Watt
• D. Coulomb per second✓
• E. Coulomb

Explanation: The unit of current is Ampere which can also be written as coulumb per second.

Q181. Fast moving electrons stopped by a heavy metallic target in an evacuated glass tube give rise to the:

• A. Beta-rays
• B. Gamma-rays
• C. X-rays✓
• D. Cosmic rays
• E. Alpha-rays

Explanation: X-ray generation occurs when heated electrons are accelerated towards a tungsten target. Upon collision, these high-speed electrons produce X-rays through two main processes: Bremsstrahlung radiation, where electrons lose energy and emit X-rays, and characteristic X-rays, which arise when inner-shell electrons are displaced, prompting higher energy electrons to fall into lower energy levels and emit X-rays with specific energies. This process is fundamental to medical imaging and various industrial applications

Q182. The alternating emf (E) generated by an AC generator is given by:

• A. E = BvL sin θ
• B. E = - NBL sin θ
• C. E = NBL cos θ
• D. E = BNAω sin(ωt)✓
• E. E = BvL cos θ

Explanation: The correct formula for the emf generated by an AC generator is E = BNAω sin(ωt). This expression accounts for the magnetic field strength (B), the number of turns in the coil (N), the area of the coil (A), and the angular velocity of the coil (ω). This formula reflects the fundamental principle that the emf induced in a coil is proportional to the rate of change of magnetic flux through the coil.The other options are incorrect as they either omit essential factors or apply to different scenarios, such as a straight conductor moving linearly through a magnetic field, rather than a rotating coil in an AC generator.

Q183. In an N-type semiconductor, the minority carriers are:

• A. Photons
• B. Electrons
• C. Protons
• D. Holes✓
• E. Neutrons

Explanation: In n-type semiconductors, the minority charge carriers are **holes**. These are created when electrons from the valence band are excited to the conduction band, leaving behind vacancies (holes) in the valence band.

Q184. The binding energy of a deuteron (IH) is 2.3 MeV, its binding energy per nucleon will be:

• A. 0.51 MeV
• B. 0.2 MeV
• C. 1.02 MeV
• D. 1.1 MeV✓
• E. 1 MeV

Explanation: The correct answer is 1.1 MeV. To find the binding energy per nucleon, you must divide the total binding energy of the nucleus by the number of nucleons. For a deuteron, which consists of one proton and one neutron, there are two nucleons. Therefore, the binding energy per nucleon is calculated as:Binding Energy per Nucleon = Total Binding Energy / Number of Nucleons = 2.3 MeV / 2 = 1.15 MeV, which rounds to 1.1 MeV.Option D is correct. Option A (0.51 MeV) and Option C (1.02 MeV) result from incorrect division. Option B (0.2 MeV) largely underestimates the value, while Option E (1 MeV) rounds down the correct value inaccurately.

Q185. The mathematical relationship between magnetic flux and magnetic flux density is:

• A. Φ = (B)(A)cosθ✓
• B. Φ = (B)(Δt)cosθ
• C. B = (ΔΦ)(Δt)cosθ
• D. B = (ΔΦ)(Δt)
• E. Φ = (B)(Δt)

Explanation: The correct mathematical relationship between magnetic flux (Φ) and magnetic flux density (B) is given by the formula: Φ = B ⋅ A ⋅ cos(θ). In this formula:Φ is the magnetic flux, representing the total magnetic field passing through a given area.B is the magnetic flux density, measuring the strength of the magnetic field.A is the area through which the magnetic field passes.θ is the angle between the magnetic field lines and the normal to the surface area.The other options are incorrect because they include inappropriate variables such as time (Δt) and changes in flux (ΔΦ), which do not belong in the formula relating magnetic flux and magnetic flux density.

Q186. If the length of a simple pendulum is increased four times, its frequency:

• A. Increases 2 times
• B. Decreases 4 times
• C. Remains the same
• D. Increases 4 times
• E. Decreases 2 times✓

Explanation: The frequency of a simple pendulum is determined by the formula f = 1/2π√(g/L), which shows that the frequency is inversely proportional to the square root of the pendulum's length.When the length L is quadrupled, the new length is 4L. The new frequency is f' = 1/2π√(g/4L) = 1/2√4 × 1/2π√(g/L) = f/2.This means the frequency decreases by a factor of 2. Thus, Option E is correct.Other options are incorrect because they do not reflect the inverse square root relationship between frequency and length in a pendulum.

Q187. In the equation of nuclear decay p^1 → →n^1 + x , x is:

• A. Proton
• B. Positron✓
• C. Electron
• D. Photon
• E. Gamma ray

Explanation: n the equation for nuclear decay p^1 →n^1 + x , the particle x represents a positively charged particle, typically a positron (e+) or beta plus particle (β+).

Q188. A force of magnitude 10N is acting along the x-axis; its component along the y-axis is:

• A. Zero✓
• B. 5N
• C. 20N
• D. 10N
• E. 25N

Explanation: The correct answer is Zero. When resolving forces into components, a force acting along the x-axis has no y-component because it is entirely in the horizontal direction. Mathematically, the y-component of a force F acting at an angle θ from the x-axis is calculated as Fy = F sin θ. Here, θ is 0 degrees since the force is along the x-axis, resulting in sin(0) = 0. Therefore, Fy = 10 N × 0 = 0 N. The other options suggest non-zero y-components, which are incorrect since they imply that the force has a component along the y-axis, which it does not.

Q189. The proton number of a nucleus increases after emission of:

• A. Negative ß particle✓
• B. Positive B particle
• C. Proton
• D. Alpha particle
• E. Neutron

Explanation: In beta-minus decay, a neutron is converted into a proton, and an electron (beta particle) is emitted. The atomic number increases by 1, changing the element to the next higher one, while the mass number remains the same.

Q190. E = k * Q / r^2 K is called:

• A. Coulomb
• B. Constant of proportionality✓
• C. Relative permittivity of the medium
• D. Permittivity of the space
• E. Permittivity of the medium

Explanation: In Coulombs' law "k" is the constant of proportionality.

Q191. Newton (N) is not the SI unit of:

• A. Centripetal force
• B. Tension
• C. Coulomb's force
• D. Friction
• E. Momentum✓

Explanation: The SI unit of momentum is kgm/s

Q192. In law of radioactive decay N = Ne, the ratio N No is called:

• A. Activity
• B. Relative activity✓
• C. Absolute activity
• D. Stability
• E. Decay constant

Explanation: Relative activity refers to the comparison of the activity level of a particular enzyme, catalyst, or biological substance under different conditions or in relation to a standard or control. It is often used to measure how changes in factors like temperature, pH, or substrate concentration affect the effectiveness or efficiency of the substance's activity. In enzyme studies, relative activity helps determine optimal conditions for maximum performance.

Q193. In Einstein's photoelectric equation hv =ϕ +eV, the kinetic energy of photoelectrons is:

• A. K.Emax=p+eV
• B. K.Emax = -eV✓
• C. K.Emax = -hv
• D. K.Emax = hv - φ
• E. K.Emax = hv-eVo

Explanation: The equation K.Emax=−eV refers to the maximum kinetic energy (K.E) of electrons in the context of the photoelectric effect or electron emission.

Q194. Faraday's law of electromagnetic induction is mathematically represented as:

• A.
• B.
• C.
• D. ✓
• E.

Explanation: Faraday's law of electromagnetic induction states that the electromotive force (EMF) induced in a circuit is proportional to the rate of change of magnetic flux through that circuit.

Q195. Read the statement given, assume it is true, and select the correct course of action:A public sector television channel is worried about the quality of its programs and, considering the competition from several private sector television channels, has decided to provide some incentives in order to attract talent for its programs.Course of action:a) Public sector television channel has decided to revise its fee structure for artists.b) It should not revise its fee structure until the private sector channels do so.

• A. Both A and B follow
• B. Only A follows✓
• C. Only B follows
• D. Neither A nor B follows
• E. Either A or B follows

Explanation: By revising its fee structure, the public sector television channel can attract better talent, which can help improve the quality of its programs and make it more competitive against private sector channels.

Q196. Parveen, Qadir, Rehan, Salim, and Tehmina are five people in a family. If Parveen is the daughter of Qadir, Qadir is the son of Rehan, Rehan is the father of Salim, while Tehmina is the daughter of Parveen, then which of the following is true?

• A. Rehan is the uncle of Parveen
• B. Qadir is the grandfather of Parveen
• C. Qadir is the daughter of Salim
• D. Parveen is the sister of Tehmina
• E. None of them✓

Explanation: Let’s break down the relationships based on the information given:Parveen is the daughter of Qadir: This means Qadir is Parveen's father.Qadir is the son of Rehan: This means Rehan is Qadir's father.Rehan is the father of Salim: This means Rehan has two children—Qadir and Salim.Tehmina is the daughter of Parveen: This means Parveen is Tehmina's mother.

Q197. Look at the numbers below. Identify the pattern and logically deduce the correct option that should follow: 1, 4, 9, 16,

• A. 54
• B. 36
• C. 49
• D. 25✓

Explanation: These numbers are perfect squares of natural numbers.The next number should logically be 5^2 = 25

Q198. Read the two statements given and select the correct optionA. Advances in cancer chemotherapy have made more drugs available today.B. A large number of cancer patients now have a better outcome.

• A. Both statements A and B are effects of some common cause.
• B. Statement A is the cause and statement B is the effect✓
• C. Both statements A and B are effects of independent causes.
• D. Statement B is the cause and statement A is the effect.
• E. Both statements A and B are independent causes.

Explanation: Statement A describes a cause: new drugs are available because of advances in chemotherapy.Statement B is the effect of that cause. Because more drugs are available (A), cancer patients are benefiting and having better outcomes (B).

Q199. Which number is a multiple of its digits?

• A. 21
• B. 47
• C. 52
• D. 24✓
• E. 13

Explanation: The digits of 24 are 2 and 4. We need to check if 24 is divisible by both 2 and 4.-> 24 / 2 = 12, which means 24 is divisible by 2.-> 24 / 4 = 6, which means 24 is divisible by 4.Since 24 is divisible by both its digits (2 and 4), it is a multiple of its digits.

Q200. Look at the alphabets below. Identify the pattern and choose the correct option that should follow next: VSA, WRD, XQG, YPJ,-----

• A. VTC
• B. TLK
• C. MOZ
• D. ZOM✓
• E. ZNE

Explanation: Observing the pattern in each letter of the sequence:First Letter:V → W → X → Y → Z (Each letter moves forward by 1 position in the alphabet)Second Letter:S → R → Q → P → O (Each letter moves backward by 1 position)Third Letter:A → D → G → J → M (Each letter moves forward by 3 positions)Following this pattern, the next term should be ZOM.