Etea Mdcat 2013 — Solved Past Paper with Answers

Q1. I keep the butter in the fridge. Select the correct passive voice:

• A. In the fridge the butter is kept by me.
• B. By me is the butter dept in the fridge.
• C. The butter is kept by me in the fridge.✓
• D. Dept in the fridge by me is the butter.

Explanation: A verb is in the passive voice when the subject of the sentence is acted on by the verb. For example, in “The ball was thrown by the pitcher,” the ball (the subject) receives the action of the verb, and was thrown is in the passive voice.

Q2. Fire destroyed the top floor of the building:

• A. The top floor of the building got destroyed by fire
• B. By fire was destroyed the top floor of the building.
• C. Destroyed by fire was the top floor of the building.
• D. The top floor of the building was destroyed by fire.✓

Explanation: Option D is correct because it adheres to the rules of forming passive voice: the object of the active sentence ('the top floor of the building') becomes the subject of the passive sentence. The verb 'destroyed' is correctly paired with the auxiliary verb 'was' to form the past tense passive voice. Options A, B, and C are incorrect due to improper sentence structure and verb usage. Option A uses an informal construction, Option B misplaces the subject and verb, and Option C incorrectly orders the elements of the sentence.

Q3. 'APPRAISE‘ means:

• A. Compliment someone publicly
• B. Describe the plot of a book
• C. Evaluate the value or quality of something✓
• D. Bargain for items in a market

Explanation: "Appraise" means to assess, evaluate, or judge the value, quality, or worth of something or someone. It involves carefully examining the object or person to determine its characteristics, strengths, weaknesses, or potential. Appraising can be done in various contexts, such as appraising the value of a property, appraising an employee's performance, or appraising the quality of a product. It often requires expert knowledge or a critical analysis to provide an informed and accurate appraisal. Appraise means to evaluate or estimate the nature, quality, ability, extent or significance. So the most appropriate option is C.

Q4. Please help someone the house is ….life.

• A. at
• B. in
• C. on✓
• D. by

Explanation: c) on: This option is the correct one. "on" is used to indicate that something is physically resting or positioned on top of something else. In this case, the house is "on fire," which means the fire is burning on the surface of the house.

Q5. 'Cranky Spouse‘ implies:

• A. A carefully selected loving partner of life
• B. Fussy and bad-tempered wife or husband✓
• C. Money squandering younger second wife
• D. A device fitted behind the rear seat of a car

Explanation: The term 'cranky spouse' combines 'cranky,' meaning irritable or bad-tempered, with 'spouse,' meaning a husband or wife. Therefore, the correct answer is Option B: 'Fussy and bad-tempered wife or husband.' Option A is incorrect as 'cranky' does not imply 'loving.' Option C incorrectly narrows the definition to a 'younger second wife' and emphasizes financial habits, which are not relevant. Option D is entirely unrelated, as it describes an inanimate object rather than a person.

Q6. Select the correct sentence:

• A. He does not know the reason of her absence.
• B. He does not know the reason around her absence.
• C. He does not know the reason for her absence.✓
• D. He does not know the reason about her absence.

Explanation: The preposition for is used both after and before reason. Therefore, the grammatically correct sentence is "He does not know the reason for her absence". Reason can also followed by a clause beginning with why or that.

Q7. An 'elegy‘ is a poem written:

• A. In the memory of a little child
• B. On the death of someone dear✓
• C. On the sighting of an old tutor
• D. In the love of a dear sweetheart

Explanation: An "elegy" is a poem written to express sorrow, grief, or lamentation, typically in response to the death of a loved one or to reflect on the passing of something significant. It is a form of poetry that is meant to evoke feelings of mourning and remembrance.ELEGY, poem lamenting the death of a public personage or of a friend or loved one; by extension, any reflective lyric on the broader theme of human mortality.

Q8. (Fix this) My children don‘t approve….. my smoking

• A. I
• B. Of✓
• C. On
• D. At

Explanation: The correct preposition to use in this sentence is 'of', as it appropriately connects the verb 'approve' with the subject 'my smoking'. The sentence 'My children don’t approve of my smoking' correctly indicates the relationship of disapproval. The other options ('I', 'on', 'at') do not provide the correct grammatical connection in this context.

Q9. 'Break the ice‘ Implies:

• A. Walk on thin ice
• B. Swallow ice-cubes
• C. Chisel an ice-block
• D. To make a beginning✓

Explanation: The correct answer is D: 'To make a beginning.' The idiom 'break the ice' refers to taking steps to initiate communication or ease tension in a social setting, particularly when people are meeting for the first time or when the atmosphere is strained. Options A and C describe literal actions involving ice, and thus do not capture the figurative meaning of the idiom. Option B is a literal action that is unrelated to the idiom's meaning.

Q10. (Fix this) Select the correct sentence:

• A. Certainly she is the best person for the job.
• B. She is the best person for the job certainly.
• C. She is certainly the best person for the job.✓
• D. The best person certainly she is for the job.

Explanation: This sentence is grammatically correct and has a natural flow. "Certainly" is placed directly before "the best person", which makes it clear that it's modifying that phrase.

Q11. 'Denounce‘ means:

• A. To reject straight away
• B. To praise in a meeting
• C. To condemn publicly✓
• D. To negotiate secretly

Explanation: The word 'denounce' means to publicly express strong disapproval or condemnation, which is why option C is correct. The other options are incorrect because they either suggest the opposite meaning (such as praising) or are unrelated to the concept of public condemnation (such as negotiating in secret or rejecting something outright).

Q12. (fix this) The police arrested him for dangerous driving. Select the correct passive voice:

• A. He was arrested for dangerous driving by the police✓
• B. He was arrested by the police for dangerous driving
• C. For dangerous driving he was arrested by the polic
• D. By the police was he arrested for dangerous driving

Explanation: This is the correct passive voice. The subject ("he") becomes the object of the sentence, and the object ("police") becomes the subject. The prepositional phrase "by the police" indicates who preformed the action.

Q13. Selaginella is the living member of :

• A. Psilopsida
• B. Lycopsida✓
• C. Sphenopsida
• D. Pterosida

Explanation: Selaginella belongs to the class of lycopsida as it has scale-leaves bearing a ligule and has spores of 2 types. It is usually treated as the only genus in the family Selaginellaceae, with over 750 known species

Q14. Contraction can be sustained for a long period of time by:

• A. Skeletal muscles
• B. Smooth muscles✓
• C. Cardiac muscles
• D. All of the above

Explanation: Smooth muscles are uniquely adapted to sustain long-term contractions with minimal energy consumption. This ability is crucial for functions such as peristalsis in the digestive tract. In contrast, skeletal muscles, while capable of brief sustained contractions, fatigue more quickly due to higher energy demands. Cardiac muscles, although enduring, are designed for continuous rhythmic contractions rather than prolonged static tension. Therefore, smooth muscles are the most efficient for sustained contractions.

Q15. Aromatic compounds generally burn with smoky flame because:

• A. They have ring structure of carbon atoms.
• B. They have a relatively high percentage of hydrogen atoms.
• C. They have a relatively high percentage of carbon atoms.✓
• D. They resist reactions with air/oxygen.

Explanation: The aromatic compound displays aromaticity. They burn with a strong sooty yellow flame. A "sooty flame" indicates that incomplete combustion is occurring and the reason for this flame is the high percentage of carbon content. The carbon-hydrogen ratio is high in aromatic compound.

Q16. Amount of DNA in a bacterial cell is:

• A. 1%✓
• B. 2%
• C. 3%
• D. 4%

Explanation: Bacterial cells are prokaryotic and lack the complex structures found in eukaryotic cells. As a result, their cellular content is streamlined, and DNA typically makes up about 1% of the cell's total composition. This percentage reflects the efficiency and simplicity of bacterial genetic material organization. The other options overestimate the amount of DNA, which is not representative of the typical bacterial cell composition.

Q17. Keratinized Epithelium is found in the:

• A. Hair
• B. Skin✓
• C. Bone
• D. Muscle

Explanation: Keratinized epithelium is a stratified squamous epithelium (consisting of flattened squamous cells arranged in layers upon the basal membrane), found in skin, epidermis of palm, sole of foot etc, therefore the answer is B.

Q18. Mushrooms belong to:

• A. Zygomycota
• B. Ascomycota
• C. Basidiomycota✓
• D. Deuteromycota

Explanation: Mushrooms belong to the phylum basidiomycota as they have a stem (stipe), a cap (pileus), and gills (lamella) on the underside of the cap, hence the answer is C.

Q19. In chick, development gives rise to:

• A. Ectoderm & Endoderm✓
• B. Ectoderm & Mesoderm
• C. Mesoderm & Endoderm
• D. Mesoderm only

Explanation: In chick, development gives rise to ectoderm and endoderm. In chick embryos, the ectoderm and endoderm cells ultimately give rise to different tissues and organs. Ectoderm cells generate the skin and neural tissue. Endoderm cells become the lining of the gastrointestinal and the respiratory tracts.

Q20. Changes in gene frequencies in small population by chance is called:

• A. Gene pool
• B. Genetic drift✓
• C. Gene mutation
• D. Gene flow

Explanation: Genetic drift is a mechanism of evolution, it refers to random fluctuations in the frequencies of alleles from generation to generation due to chance of events, therefore the answer will be B.

Q21. N2(g) + 3H2 (g) ------> 2NH3(g), △H= 46.1 kj/moleFor the reaction above which statement is true about the equilibrium constant (Keq):

• A. Keq increases with an increase in temperature✓
• B. Keq decreases with an increase in temperature
• C. Keq decreases with an increase in pressure
• D. Keq increases with a decrease in pressure

Explanation: The value of △H is positive which means the reaction is endothermic and heat is absorbed. So if we increase the temperature, the equilibrium will favour the right hand side i.e more products will be formed.

Q22. Number of chromosomes in Tobacco is:

• A. 45
• B. 48✓
• C. 46
• D. 47

Explanation: The correct number of chromosomes in tobacco is 48. Tobacco is an allopolyploid species, which means it has multiple sets of chromosomes originating from different species. Each gamete contains 24 chromosomes, resulting in a total of 48 chromosomes in somatic cells. The other options, 45, 46, and 47, do not reflect the correct chromosome count for tobacco. Option A (45) and Option D (47) are incorrect as they do not represent the known chromosome numbers for tobacco. Option C (46) is the diploid number for humans, not tobacco.

Q23. Appendix is vestigial in man but may play role in:

• A. Digestion
• B. Excretion
• C. Immunity✓
• D. Movement

Explanation: The appendix has been found to play a role in mammalian mucosal immune function. It is believed to be involved in extrathymically derived T-lymphocytes and B-lymphocyte mediated immune responses and is also said to produce early defenses that help prevent serious infections in humans. Therefore the answer is C.

Q24. Urea formation occurs in:

• A. Kidney
• B. Liver✓
• C. Spleen
• D. Lungs

Explanation: b) Liver:This option states that urea formation occurs in the liver. This statement is correct. The liver is the primary site of urea formation in the body. It is an essential part of the process known as the urea cycle, where toxic ammonia (a byproduct of protein metabolism) is converted into urea, a less toxic compound. Urea is then transported to the kidney for excretion in urine.

Q25. Phagocytosis, pinocytosis and autophagy are the functions of:

• A. Golgi-Apparatus
• B. Lysosomes✓
• C. Peroxisomes
• D. Glyoxisomes

Explanation: Lysosomes perform phagocytosis, pinocutosis and autophagy as they contain enzymes to digest foreign material and casue cell death.

Q26. A student measures a current as 0.05 A. Which of the following correctly expresses this result?

• A. 50 mA✓
• B. 50 µA
• C. 500 mA
• D. 500 µA

Explanation: The current of 0.05 A can be expressed as 50 mA because 'milli' means one thousandth, making 0.05 A equivalent to 50 milliamperes. Option A is correct. Option B (50 µA) and Option D (500 µA) are incorrect because microamperes are much smaller than milliamperes. Option C (500 mA) is incorrect because it represents a larger current than 0.05 A.

Q27. Spiders belong to class:

• A. Crustacea
• B. Myriapoda
• C. Arachnida✓
• D. Hexapoda

Explanation: Spiders belong to the class Arachnida, which includes joint-legged animals like scorpions, ticks, and mites. Arachnids are distinct from other arthropods due to their eight-legged structure, lack of antennae, and body divided into two main segments. Unlike crustaceans, arachnids are not primarily aquatic. They also differ from myriapods, which have many body segments and legs, and from hexapods (insects), which have six legs and three body segments.

Q28. Polysaccharide cellulose is the building material of:

• A. Primary cell wall✓
• B. Secondary cell wall
• C. Middle lamella
• D. Plasma membrane

Explanation: Cellulose is a crucial polysaccharide that forms the structural component of the primary cell wall in plants. It provides tensile strength and rigidity, allowing the plant to maintain its shape. The secondary cell wall, although providing additional support, is not primarily composed of cellulose but rather lignin and other compounds. The middle lamella is mainly composed of pectin and acts as an adhesive between cells. The plasma membrane is not part of the cell wall and does not contain cellulose, as it is primarily made up of lipids and proteins.

Q29. Lobsters belong to class:

• A. Myriapoda
• B. Arychnida
• C. Hexapoda
• D. Crustacean✓

Explanation: Crustaceans form a very large group of arthropods, which includes crabs, lobsters, crayfish etc. They are distinguished from other groups, like insects by possession of biramous limbs an the nauplius form of the larvae. Hence the answer is D.

Q30. Pigeon odour is released from the water bloom of:

• A. Slime mold
• B. Water mold
• C. Cyanobacteria
• D. Cyanobacteria Algae ponds✓

Explanation: The correct answer is Cyanobacteria Algae ponds. Cyanobacteria, often called blue-green algae, can form dense blooms in water, releasing odors due to the organic compounds they produce. These blooms can make the water smell unpleasant and affect its quality. Slime molds and water molds, while they exist in moist environments, do not typically contribute to offensive odors in water bodies. Cyanobacteria, due to their ability to proliferate rapidly in nutrient-rich waters, are the main culprits behind such issues.

Q31. Brunner‘s glands are found in:

• A. Stomach
• B. Duodenum✓
• C. Ileum
• D. Colon

Explanation: Brunner’s glands are branched tubular mucus glands normally found in the mucosa and submucosa of the duodenum. Therefore the answer is B.

Q32. An organism that adopts saprophytic mode of nutrition during part of its life is called:

• A. Facultative saprophyte✓
• B. Facultative parasite
• C. Obligate saprophyte
• D. Obligate parasite

Explanation: Saprophytic is the mode of nutrition in which organisms feed on dead and decayed matter, a facultative saprophyte ia a mainly parasitic organism with the ability to survive for a part of its life cycle as a saprophyte, therefore the answer will be A.

Q33. Erepsin acts upon:

• A. Polypeptides
• B. Carbohydrates
• C. Dipeptides✓
• D. Fats

Explanation: Erepsin consists of many enzymes and works best in alkaline pH. It doesn't act upon proteins but does act upon lower peptides such as dipeptides, hence the answer will be C.

Q34. Microsporum furfur causes:

• A. Athlete's foot
• B. Ringworm✓
• C. Dandruff
• D. None of these

Explanation: Microsporum furfur is a fungus that can cause ringworm, a type of dermatophyte infection. It affects the keratinized tissues like skin, hair, and nails. Athlete's foot is associated with Trichophyton fungi, and dandruff is linked to Malassezia. Therefore, the correct answer is B: Ringworm.

Q35. The gills are covered by operculum in

• A. Bony fishes✓
• B. Cartllaginous fishes
• C. Lung fishes
• D. Jawless fishes

Explanation: The operculum is a hard, plate-like bony flap that covers the gills of a bony fish protecting the gills and also serves a role in respiration. Hence the answer will be A.

Q36. A sporophyte that depends on gametophytes is:

• A. Adlantum
• B. Pinus
• C. Marchantia✓
• D. Mustard-plant

Explanation: Bryophytes (mosses, liverworts and hornworts) have dominant gametophyte phase on which the adult sporophyte is depended for nutrition. Marchantia is a type of bryophyte.

Q37. Which is not correct about polyvinyl chloride?

• A. It is used in large scale production of cable insulator
• B. It is a copolymer✓
• C. It is a homopolymer
• D. It is used in the manufacturing of pipes

Explanation: b) It is a copolymer:This option states that polyvinyl chloride is a copolymer. This statement is not correct. PVC is not a copolymer; it is a homopolymer. A homopolymer is a type of polymer that is composed of repeating units of a single monomer. In the case of PVC, the repeating unit is vinyl chloride (CH2=CHCl).

Q38. Replication progresses at a rate of about 50 base pairs per second in:

• A. Bacteria
• B. Virus
• C. Eukaryote✓
• D. All of the above

Explanation: In eukaryotes, such as humans, DNA replication occurs at approximately 50 base pairs per second. This slower rate compared to prokaryotes is due to the complexity of eukaryotic chromosomal structures and the presence of multiple origins of replication. Bacteria replicate at a much faster rate of about 1000 nucleotides per second due to their simpler circular DNA and fewer regulatory complexities. Viruses do not have a fixed replication rate as it varies significantly depending on the virus type and the host cell machinery they exploit. Therefore, the correct answer is C: Eukaryote.

Q39. The pigments of chlorophyll a,b, and carotenoids are present in:

• A. Stroma
• B. Grana
• C. Thylakoid membrane✓
• D. Crista

Explanation: The correct answer is the thylakoid membrane. This is where the pigments chlorophyll a, b, and carotenoids are located, as they are crucial for capturing light energy and facilitating the light-dependent reactions of photosynthesis. The other options are incorrect because the stroma is where the Calvin cycle occurs, not where the pigments are located; grana are stacks of thylakoids, and while they house the thylakoid membranes, the pigments are specifically in the membranes themselves; and cristae are part of mitochondria, not chloroplasts, and play a role in cellular respiration, not photosynthesis.

Q40. Which one of the following animals is filter feeder?

• A. Teeth
• B. Sycon✓
• C. Fresh water mussels
• D. Jelly fish

Explanation: Sycon are sponges that receive food particles with the help of collar cells, therefore are called filter feeders.

Q41. Myoglobin is found in:

• A. Bone
• B. Connective tissue
• C. Muscles✓
• D. Cartilage

Explanation: Myoglobin is a protein found in muscle fibers, responsible for storing oxygen and facilitating its availability during muscle contraction. This is crucial to meet the high oxygen demands for energy production within muscle cells. Unlike bones, connective tissue, and cartilage, muscles require direct oxygen availability for sustained activity, which is why myoglobin is present there. Bones, connective tissue, and cartilage serve structural and supportive roles and do not have the same oxygen storage needs.

Q42. Thalassaemia major is also known as:

• A. Sickle cell anemia
• B. Cooley's anemia✓
• C. Microcytic anemia
• D. Nutritional anemia

Explanation: Thalassaemia major is also known as Cooley's anemia, named after Thomas B. Cooley, who identified the genetic disorder characterized by reduced hemoglobin production. Sickle cell anemia is a separate genetic condition involving abnormally shaped red blood cells. Microcytic anemia is a general term for small red blood cells, often due to iron deficiency, and can be a symptom of thalassaemia but not a synonym. Nutritional anemia results from nutrient deficiencies, unlike the genetic nature of thalassaemia.

Q43. The birds excrete:

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

Explanation: Birds excrete nitrogenous waste primarily in the form of uric acid. This adaptation is crucial for conserving water, as uric acid requires minimal water to be excreted, allowing birds to thrive in environments where water is scarce. In contrast, ammonia and urea require more water to be safely eliminated from the body, making them more suitable for aquatic animals and mammals, respectively. Acetic acid is not relevant to the excretory processes of birds.

Q44. Bulliform cells are present in:

• A. Grasses✓
• B. Under ground stems
• C. Fruit-nuts
• D. Cabbage leaves

Explanation: Bulliform cells or motor cells are large, bubble-shaped epidermal cells that occur in grps on the upper surface of the leaves of many monocots. Grass is monocot and contains bulliform cells.

Q45. Bone is surrounded by a membrane called:

• A. Perichondrium
• B. Prostomium
• C. Perimycium
• D. Periosteum✓

Explanation: The correct answer is periosteum. The periosteum is a dense fibrous membrane covering the surface of bones. It plays a vital role in bone growth and repair and contains blood vessels and nerves that supply nutrients and sensation to the bone.The perichondrium surrounds cartilage, not bone. The prostomium is unrelated to bone, being a part of certain invertebrates. Perimycium pertains to muscle tissue, not bone.

Q46. A hormone that prevents senescence in leaves, is:

• A. Auxin
• B. Gibberellins
• C. Cytokinin✓
• D. Abscisic acid

Explanation: Leaf senescence is a degenerative process among which cellular organelles and biomolecules are broken down and resultant catabolites are mobilized to sink tissues such as reproductive organs and new leaves. Cytokinins help to maintain the plant cells and expression of cytokinin biosynthesis genes late in development prevents leaf senescence. Hence the answer is C.

Q47. Meissner corpuscles are the receptors for

• A. Temperature
• B. Pain
• C. Pressure
• D. Touch✓

Explanation: Meissner corpuscles are integral to the human sensory system, specifically involved in detecting light touch. These mechanoreceptors are located just beneath the skin's surface, particularly in areas like fingertips and lips, where sensitivity is high. They enable the perception of fine details and textures, which is why the correct answer is D. The other options are incorrect because temperature is detected by thermoreceptors, pain by nociceptors, and pressure by other mechanoreceptors like Pacinian corpuscles.

Q48. Florigen is produced by:

• A. Flowers
• B. Flower-buds
• C. Leaves (CORRECT)✓
• D. Fruits

Explanation: Florigen is a plant hormone produced in the leaves. It acts as a long-distance signaling molecule that travels to the shoot apical meristem, promoting the transition from vegetative growth to flowering. This process is crucial for the plant's reproductive success. Option C is correct because leaves are where this hormone is synthesized. Options A, B, and D are incorrect as flowers, flower-buds, and fruits do not produce florigen. They play roles in the reproductive cycle of plants but are not the source of this specific hormone.

Q49. Who used puzzle boxes in experiment on animal learning?

• A. Ivan Pavlov
• B. E.L. Thorndike✓
• C. Konrad Lorenz
• D. Wolfgang Köhler

Explanation: Edward Thorndike is the correct answer because he conducted experiments using puzzle boxes to study learning in animals. His work with cats demonstrated the process of trial and error learning, which contributed to the foundation of behaviorist theories such as operant conditioning.Ivan Pavlov, known for his research on classical conditioning, did not use puzzle boxes. Konrad Lorenz focused on imprinting in birds, and Wolfgang Köhler studied insight learning in apes. None of these researchers used puzzle boxes in their work.

Q50. Which one of the following animals is viviparous?

• A. Rat✓
• B. Kangaroo
• C. Duckbilled platypus
• D. Spiny ant eater

Explanation: Viviparous species are those who give birth to living young ones directly instead of laying eggs. Rats are viviparous, therefore the correct answer will be A.

Q51. Cristea of mitochondria are the sites of:

• A. Electron transport chain✓
• B. Photophosphorylation
• C. Krebs cycle
• D. Glycolysis

Explanation: The correct answer is A, the electron transport chain, which occurs on the cristae of the mitochondria. These folds provide a large surface area for the chain's protein complexes to facilitate ATP production. Photophosphorylation (Option B) occurs in chloroplasts, not mitochondria. The Krebs cycle (Option C) takes place in the mitochondrial matrix, not the cristae. Glycolysis (Option D) occurs in the cytoplasm, outside of the mitochondria.

Q52. Muscles develop from:

• A. ectoderm
• B. mesoderm✓
• C. endoderm
• D. all of the above

Explanation: Muscles develop from the mesoderm, which is one of the three primary germ layers in the early embryo. The mesoderm also gives rise to the skeletal and reproductive systems. The ectoderm forms the skin and nervous system, while the endoderm develops into the lining of the digestive and respiratory systems. Thus, the correct answer is B: mesoderm.

Q53. Bacteria maintain their survival by the formation of:

• A. Hormogonia
• B. Akinetes
• C. Endospores✓
• D. Zygospores

Explanation: Endospores are the correct answer because they are specialized, durable structures that allow bacteria to survive in unfavorable conditions. Unlike akinets or hormogonia, endospores can withstand extreme environmental stresses such as heat, desiccation, and chemicals. Zygospores, on the other hand, are related to fungi and protists and are not relevant to bacterial survival.

Q54. Avery, Macleod and McCarty repeated the Griffith experiment in the year:

• A. 1869
• B. 1928
• C. 1944✓
• D. 1952

Explanation: 16 years later in 1944 they repeated the Griffith experiment to figure out what component of the dead S strain of bacteria were responsible for the transformation. Hence the answer will be C.

Q55. Microvilli are also called:

• A. Leaf veins
• B. Cristae
• C. Capillaries
• D. Brush border✓

Explanation: Microvilli are small, finger-like projections on the surface of epithelial cells, especially in the small intestine, where they are known as the 'brush border'. This term comes from the appearance of microvilli under a microscope. The brush border increases the surface area for absorption. The other options are incorrect: 'Cristae' are related to mitochondria, 'Capillaries' are blood vessels, and 'Leaf veins' and 'Leaf midribs' are plant structures.

Q56. Cell death due to tissue damage is called:

• A. Necrosis✓
• B. Metastasis
• C. Apoptosis
• D. Epistasis

Explanation: [A] Necrosis is the death of a body tissue,occurring when too little blood flows to the tissue.[B]Metastasis means that cancer has spread to different parts of body[C] Apoptosis the process of programmed cell death[D] Epistasis is a circumstance where the expression of one gene is modified by expression of one or more gene

Q57. The two chains of DNA occur side by side in a:

• A. Straight direction
• B. Parallel but straight
• C. Antiparallel and straight
• D. Antiparallel and spirally twisted✓

Explanation: DNA is a double helix formed by two strands of nucleotides. These strands run in opposite directions (antiparallel) and are twisted around each other, creating a spiral structure. This configuration allows for the stability and functionality of DNA as it holds genetic information. The correct option highlights these key characteristics: antiparallel orientation and a spiral twist. Other options incorrectly describe DNA as straight or simply parallel, which does not match the known helical structure.

Q58. In which of the following is the phenotypic and genotypic ratio the same?

• A. Co-dominance
• B. Over dominance
• C. Epistasis
• D. Incomplete dominance✓

Explanation: In incomplete dominance, the heterozygous phenotype is a blend of the two homozygous phenotypes, resulting in a phenotypic ratio that matches the genotypic ratio. For instance, in snapdragons, crossing red (RR) with white (rr) results in pink (Rr) offspring, where the intermediate phenotype is directly reflective of the genotype. This differs from co-dominance, over dominance, and epistasis, where phenotypic expressions create ratios different from the genotypic ratios due to various interactions and expressions of the alleles.

Q59. A cell-wall that is composed of sugar and amino acids is called:

• A. Murein✓
• B. Chitin
• C. Lignin
• D. Pectin

Explanation: Peptidoglycan or murein is a polymer consisting of sugars and amino acids that forms a mesh-like peptidoglycan layer outside the plasma membrane of most bacteria, forming the cell wall. Hence the correct answer would be A.

Q60. A plant or animal modified by genetic engineering is called:

• A. Transgenic✓
• B. Probe
• C. Recombinant
• D. Plasmid

Explanation: These plants and animals are called transgenic or genetically modified organisms, a probe is a single stranded DNA or RNA sequence used to search for its complementary sequence. A plasmid is a small circular double stranded DNA found in bacteria and used for storing and studying genes whereas a recombinant DNA is one that takes up foreign genes. Hence the answer will be A.

Q61. When the entire body of a bacterium is covered by flagella, such a bacterium is called:

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

Explanation: Bacteria are classified based on the arrangement of their flagella, which affects their motility. Peritrichous bacteria have flagella all over their surface, enabling them to move in various directions efficiently. This is in contrast to atrichous bacteria, which lack flagella entirely and are non-motile. Lophotrichous and amphitrichous bacteria have flagella localized to specific areas, either in bundles at one end or at both ends, respectively. Thus, the correct answer is D: Peritrichous.

Q62. Phosphorus trihalides are readily hydrolysed as shown below:PX3 + 3H2O → H3PO3 + 3HXGenerally moving from fluorine to iodine rate of hydrolysis:

• A. Increases✓
• B. Decreases
• C. Remains unchanged
• D. First increases and then decreases

Explanation: Down the group, from fluorine to iodine the reactivity increases as the bond energy decreases, making it easier for the phosphorus trihalides to be hydrolysed.

Q63. Nucleus was discovered by:

• A. Waldyne
• B. T.H. Margan
• C. Robert Brown✓
• D. Kohler

Explanation: The correct answer is Robert Brown, who discovered the cell nucleus in 1831 while examining plant cells under a microscope. His observations laid foundational work for cell biology. Other options like Waldyne and Kohler are not associated with this discovery, and T.H. Margan is a misspelling of T.H. Morgan, who was unrelated to the discovery of the nucleus.

Q64. Which of the following is not a nucleophile?

• A. NH3
• B. OH
• C. CN-
• D. Br2✓

Explanation: Br₂ is not a nucleophile because:No Significant Negative Charge:Nucleophiles are electron-rich species that donate electrons.Br₂ is a neutral molecule with no formal negative charge, making it less likely to donate electrons.Weak Electron Donation Ability:Even though Br atoms have lone pairs, they are held tightly and not readily available for donation.Instead, Br₂ tends to act as an electrophile (electron acceptor), especially in reactions like electrophilic addition.Polarizability but No Strong Nucleophilic Character:Br₂ is a polarizable molecule, meaning it can momentarily develop dipoles, but this does not make it a nucleophile.In reactions, Br₂ often undergoes heterolytic cleavage, forming Br⁺ (electrophile) and Br⁻ (nucleophile), where only Br⁻ is nucleophile.

Q65. Stroma of chloroplasts carries the fixation of

• A. N2
• B. O2
• C. CO2✓
• D. NH3

Explanation: The stroma of chloroplasts is where the Calvin cycle occurs, which is responsible for fixing carbon dioxide (CO2) into organic molecules like glucose. This process uses ATP and NADPH generated during the light-dependent reactions. In contrast, nitrogen fixation, crucial for converting atmospheric nitrogen (N2) into a form usable by plants, is performed by certain bacteria. Oxygen (O2) is a byproduct, not a fixed compound in photosynthesis, and ammonia (NH3) is involved in processes outside the chloroplast.

Q66. What will be the anti-coden of AUG?

• A. TAC
• B. ATC
• C. UAC✓
• D. UTC

Explanation: AUG is the start codon that signals ribosomes to place in the amino acid methionine because the tRNA that has methionine attached to it has the anticodon sequence UAC. Therefore, the answer will be C.

Q67. Potatoe plastids, which store starch, are known as

• A. Paramylum
• B. Amyloplasts✓
• C. Leucoplasts
• D. Glycoplasts

Explanation: The correct answer is Amyloplasts. These are specialized plastids within plant cells that synthesize and store starch granules. They are particularly abundant in storage tissues like those found in potato tubers. Paramylum is not a plant plastid but a starch-like compound found in some algae and protozoans. Leucoplasts are a broader category of plastids that store various substances, but they are not exclusively associated with starch storage. Glycoplasts do not exist and are not relevant to the question.

Q68. Which has the lowest temperature?

• A. Troposphere
• B. Stratosphere
• C. Mesosphere✓
• D. Thermosphere

Explanation: The top of the mesosphere, called the mesopause is the coldest part of the earth’s atmosphere averaging about minus 130 degrees F. Hence the correct answer will be C.

Q69. The prefix 'tera‘ stands for

• A. 104
• B. 109
• C. 10-6
• D. 1012✓

Explanation: Tera donates multiplication by one trillion or 10¹².OPTION A: The prefix "myria" OPTION B: The prefix "Giga" stands for 10^9.OPTION C: The prefix "micro" stands for 10^-6.

Q70. The phenomenon that a seed fails to germinate in spite of providing all conditions necessary for germination is _

• A. Photoperiodism
• B. Vernalization
• C. Dormancy✓
• D. Phytochrome

Explanation: Seeds of some plants do not germinate even under favourable conditions. This is called dormancy. It is under endogenous control.

Q71. Which one of the following is a sex-linked inheritance?

• A. Baldness✓
• B. Albinism
• C. None of these
• D. Myopia

Explanation: Males with higher testosterone levels have a dominant baldness gene, whereas females with lower testosterone levels have a recessive baldness gene. So baldness has sex linked inheritance.

Q72. When the light from two lamps falls on a screen, no interference pattern can be obtained. Why is this?

• A. The lamps are not point sources.
• B. The lamps emit light of different amplitudes.
• C. The light from the lamps is not coherent.✓
• D. The light from the lamps is white.

Explanation: When light from two separate lamps falls on a screen, interference patterns typically do not form because the light from each lamp is not coherent. In order to observe interference patterns, the light sources need to be coherent, which means that the light waves emitted by the sources have a constant phase difference between them.

Q73. The valve between left ventricle and aorta is called:

• A. Semi lunar valve✓
• B. Blcuspid valve
• C. Tricuspid valve
• D. Pulmonary valve

Explanation: The term semilunar refers to the aortic valve and the pulmonary valve, tricuspid is the valve between the right atrium and ventricular and bicuspid between left atrium and ventricular. Hence the answer will be A.

Q74. Which of the following misnamed?

• A. Aniline
• B. Methyl naphthalene
• C. Carboxyl benzene✓
• D. Benzene sulphonic acid

Explanation: The correct answer is Option C: Carboxyl benzene. The name 'Carboxyl benzene' is misnamed because the correct nomenclature for a benzene ring with a carboxyl group is 'benzoic acid' (C6H5COOH). Option A, 'Aniline', is correctly named as it refers to an aromatic amine with the formula C6H5NH2. Option B, 'Methyl naphthalene', is a correct name for a naphthalene derivative. Option D, 'Benzene sulphonic acid', is also correctly named, representing a benzene ring with a sulphonic acid group attached. Thus, Option C is the only misnamed compound.

Q75. Why is the boiling point of n-Pentane about 28‘C higher than that of its 2,2-Dimethylpropane isomer?

• A. The small surface area of 2,2-Dimethylpropane leads to weaker intermolecular forces.✓
• B. 2,2-Dimethylpropane molecules experience repulsive forces.
• C. N-Pentane molecules have difficulty interacting closely with each other.
• D. Molecular shape has no impact on boiling point.

Explanation: The correct answer is A. The boiling point of a hydrocarbon is influenced by the strength of intermolecular forces, which depend on molecular shape and surface area. N-Pentane, with its linear structure, has a larger surface area, allowing stronger Van der Waals forces between molecules compared to the more compact, branched shape of 2,2-Dimethylpropane. This results in n-Pentane having a significantly higher boiling point.Options B, C, and D are incorrect because they fail to recognize the influence of molecular shape and surface area on intermolecular forces, which are critical in determining boiling points.

Q76. Which one of the following will not undergo dehydrogenation?

• A. COCH3✓
• B. (CH 3)2 CHOH
• C. (CH3)3COH
• D. CH3CH2OH

Explanation: To undergo dehydrogenation, the compound must have OH group. Only compound in option A is not an alcohol thus, it is the correct answer.

Q77. Which one is a polymer substance?

• A. Glass
• B. Iron
• C. Plastic✓
• D. copper

Explanation: A polymer is a substance made of many repeating units called monomers. Plastics are formed by many identical repeating monomers thus are polymers.

Q78. The heat of combustion of hydrocarbon is very useful source of heat and power, considering the combustion reaction given below. CH4(g) +O2(g) →CO2(o) + 2H2O △H for the reaction is:

• A. △H = 213 kcal/mole✓
• B. △H = 231 kcal/mole
• C. △H = 426 kcal/mole
• D. △H = 312 kcal/mole

Explanation: The enthalpy of combustion of methane (CH4) is -890 kJ/mol. To convert this to kilocalories, use the conversion factor 1 kJ = 0.239 kcal. Therefore, -890 kJ/mol × 0.239 kcal/kJ = -212.715 kcal/mol, which rounds to approximately -213 kcal/mol. This makes Option A correct. The other options provide values that are not consistent with this conversion and the known enthalpy of combustion for methane.

Q79. Rain water becomes acidic, when the pH-value of rain water becomes _

• A. Greater than 6
• B. Greater than 6.5
• C. Less than 5.6
• D. Less than 5✓

Explanation: Normal clean rain has a pH value between 5.0 - 5.5, which is slightly acidic, however when rain combines with nitrogen oxides or SO2, it becomes more acidic has the pH drops below 5.0. Therefore the answer is D.

Q80. Drinking water should be odorless, tasteless and live from turbidity and its pH should range between:

• A. 6.0 to 7.0
• B. 7.0 to 8.5✓
• C. 4.5 to 6.0
• D. 8.5 to 9.0

Explanation: It is recommended that the pH of drinking water should be between 6.5-8.5 on a scale that ranges from 0 - 14, hence the answer will be B.

Q81. How many molecules are present in 0.20 g of Hydrogen gas? Select the correct option.

• A. 0.20 x 3.01 x 1023✓
• B. 0.20 x 2.016
• C. 0.70 x 6.02 x 1023
• D. 1.008 x 6.02 x 1023

Explanation: To find the number of molecules in 0.20 g of hydrogen gas, first recognize that hydrogen gas (H2) is diatomic. This means that 1 mole of hydrogen gas, which weighs 2.016 g, contains 6.02 x 1023 molecules. Therefore, 1 g of hydrogen gas contains 3.01 x 1023 molecules. To find the number of molecules in 0.20 g, multiply 0.20 by 3.01 x 1023, yielding 0.20 x 3.01 x 1023 molecules.Option A correctly uses this method. Option B fails by using the molar mass without Avogadro's number, Option C uses an incorrect proportion, and Option D uses the atomic mass of hydrogen instead of the diatomic gas.

Q82. In a nuclear fission reaction, what molecules are produced?

• A. Neutrons✓
• B. Protons
• C. Electrons
• D. Alpha particles

Explanation: When a nucleus fissions, it splits into several smaller fragments. These fragments, or fission products, are about equal to half the original mass. Two or three neutrons are also emitted.

Q83. A single molecule of haemoglobin is composed of:

• A. Three polypeptide chains
• B. Four polypeptide chains✓
• C. Five polypeptide chains
• D. Six polypeptide chains

Explanation: Haemoglobin is a quaternary structure therefore its composed of four polypeptide chains, 2 alpha globins and 2 beta globins. Therefore the answer will be B.

Q84. Which of following functional groups are deactivating and not ortho, para directing?

• A. –R
• B. –COR✓
• C. –NH2
• D. NR2

Explanation: Ortho and para directing grps release electrons to the benzene ring increasing the chemical reactivity of the benzene ring towards electrophiles. Meanwhile meta directing grps withdraw the electrons from the benzene ring towards themselves decreasing their availability towards electrophiles. Therefore the answer will be B.

Q85. In which of the following pairs are both substances normally crystalline?

• A. Copper and diamond✓
• B. Copper and glass
• C. Copper and rubber
• D. Diamond and glass

Explanation: Diamond is a crystal that is transparent to opaque and generally isotropic, native copper is a polycrystal. Therefore the answer will be A.

Q86. Which one of the following is strongest acid?

• A. CH3COOH
• B. CH3CH2COOH
• C. C6H5CG2COOH
• D. FCH2COOH✓

Explanation: D is the correct option, as it contains a halogen which have strong electron-withdrawing effects.

Q87. To distinguish among primary, secondary and tertiary alcohols which of the following tests is used?

• A. Benedicts reagent
• B. Tollen‘s reagent
• C. Lucas test✓
• D. None of the above

Explanation: The lucas test is used to differentiate between primary, secondary and tertiary alcohols,an oily layer of alkyl halides separates out in these reactions. With the oily layer being formed immediately in tertiary alcohols, in 5 - 10mins in secondary and only on heating in primary. Therefore the answer is C.

Q88. Which one of the following compound participates in hydrogen bonding?

• A. CH3
• B. CH3 OCH3
• C. CH3NH3✓
• D. C6 H5 OCH3

Explanation: Hydrogen bonding is possible when a hydrogen atom is bonded to another electronegative atom like O,F,N etc therefore the answer will be C.

Q89. Which of the following structure has a bond formed by an overlap of sp2 hybrid orbital with that of sp2 hybrid orbital?

• A. HC = CH
• B. H2C = CH2✓
• C. H2C = C= CH2
• D. CH2= CHCH3

Explanation: The C-C sigma bond in ethylene is formed by the overlap of an sp2 hybrid orbital from each carbon. The overlap of hybrid orbitals or a hybrid orbital and a 1s orbtial from hydrogen creates the sigma bond framework of the ethylene molecule.

Q90. The bond angle between H-C-H bond in ethane is:

• A. 109.5✓
• B. 120
• C. 90
• D. 107.5

Explanation: Ethane, C2H6, has a geometry related to that of methane. The two carbons are bonded together, and each is bonded to three hydrogens. Each H-C-H angle is 109.5° and each H-C-C angle is 109.5°.

Q91. What will be the product when PCl5 reacts with acetic acid?

• A. CH3CI
• B. CH3COCI✓
• C. CH3COCI2
• D. CH3CH2COCI

Explanation: When PCl5 reacts with acetic acid CH3COOH, an acyl chloride acetyl chloride is formed:CH3COOH + PCl5 CH3COCl +POCl3 +HCl

Q92. Which type of isomerism is being exhibited by FCH = CHF?

• A. Chain isomerism
• B. Structural isomerism
• C. Geometrical isomerism✓
• D. Position isomerism

Explanation: Geometric isomers possess the same structural formula containing a double bond and differ only in respect of the arrangements about the double bond, hence the answer will be C.

Q93. Which is the correct product formed when monohydric alcohol reacts with sodium metal?

• A. Alkene
• B. Sodum alkoxide✓
• C. Alkane
• D. Ether

Explanation: When alcohols react with metals a salt is formed,the reaction when a monohydric alcohol reacts with sodium metal results in the production of sodium alkoxide and hydrogen gas, hence the answer is B.

Q94. Coal, natural gas and petroleum are generally called:

• A. Fossil fuels✓
• B. Renewable sources
• C. Infiinite sources
• D. None of the above

Explanation: Coal, natural gas and petroleum are all generally called fossil fuels and are nonrenewable sources of energy.

Q95. In a vibrating cord the point where the particles are stationary is called:

• A. Crest
• B. Anti-node
• C. Node✓
• D. Trough

Explanation: A node is a point along a standing wave where the wave has minimum amplitude. All the particles of the string execute SHM except nodes.

Q96. Benzene reacts with acetyl chloride in the presence of lewis acid forming:

• A. Chlorobenzene
• B. Acetophenone✓
• C. Benzoic acid
• D. Benzophenone

Explanation: The reaction between benzene and acetyl chloride in the presence of lewis acid results in the formation of an aryl ketone , methyl phenyl ketone also known as acetophenone, hence the answer is B.

Q97. When 2-Bromo-2-methyl propane undergoes unimolecular elimination reaction, the product obtained will be:

• A. 2-Methyl propane
• B. 2-Methyl propene✓
• C. 2-Methyl-1 propanol
• D. 2-pentanol

Explanation: The unimolecular elimination (E1) reaction of 2-Bromo-2-methyl propane involves the removal of the bromine atom, resulting in the formation of a carbocation. This intermediate then undergoes rearrangement to form the most stable alkene, which in this case is 2-Methyl propene, an alkene with a double bond.Option A, 2-Methyl propane, is incorrect because the elimination reaction leads to an alkene, not an alkane. Option C, 2-Methyl-1 propanol, is incorrect because no alcohol is formed in this type of reaction. Option D, 2-pentanol, is incorrect because the starting material does not have the carbon chain length necessary to form 2-pentanol.

Q98. When lead, 81Pb214, emits a ß- particle, the resultant nucleus will be:

• A. 83Bi214
• B. 84Po214
• C. 82Pb214✓
• D. 41TI214

Explanation: In beta decay, a neutron in the nucleus is transformed into a proton and a beta particle (an electron) is emitted. This results in an increase in the atomic number by 1 while the mass number remains unchanged. Thus, when lead, 81Pb214, emits a beta particle, it transforms into 82Pb214. The other options are incorrect as they either show an incorrect change in atomic number or involve elements that do not result from beta decay of lead.

Q99. Vinyl acetate monomer is prepared by the reaction of acetaldehyde and acetic-anhydride. The catalyst employed is:

• A. FeCl3✓
• B. Al2O3
• C. V2O5
• D. Cr2O3

Explanation: The industrial synthesis of vinyl acetate involves the reaction of ethylene, acetic acid, and oxygen over a palladium catalyst. Palladium(II) chloride is a key component of the catalyst system for this reaction.

Q100. Thermal processing of industrial waste material aims at:

• A. Burning of waste material in pits
• B. Converting the solid waste into useful products by thermal treatment✓
• C. Energy recovery from organic matter prior to its final disposal
• D. Size reduction and compaction by thermal process

Explanation: The primary function of thermal treatment is to convert the waste to a stable and usable end product. Therefore the answer will be B.

Q101. Which one is not a nitrogenous fertilizer?

• A. Ammonium nitrate
• B. Triple phosphate✓
• C. Urea
• D. Nitro phosphate

Explanation: The correct answer is Triple phosphate. It is a phosphate fertilizer, primarily providing phosphorus rather than nitrogen. Ammonium nitrate, Urea, and Nitro phosphate all contain nitrogen, making them nitrogenous fertilizers. While Nitro phosphate is not primarily used as a fertilizer, it still contains nitrogen, which disqualifies it as the correct answer in this context.

Q102. In chlorophyII-b, the porphyrine ring is attached to the:

• A. Methyl group
• B. Carboxyl group
• C. Aldehyde group✓
• D. Hydroxyl group

Explanation: The porphyrin ring in chlorophyll-b is specifically attached to an aldehyde group, which includes a carbonyl group (C=O) bonded to a hydrogen atom. This distinguishes it from chlorophyll-a, where the attachment is a methyl group. Methyl groups (CH3) are simple carbon groups not present in chlorophyll-b's structure. Carboxyl groups (COOH) and hydroxyl groups (OH) are not involved in the attachment of the porphyrin ring in chlorophyll-b.

Q103. Which of the following titrants would most likely be used as ths‘ own indicator in acid medium?

• A. K2Cr2O7 (Potassium dichromate)
• B. Iodine (I2)
• C. KMnO4 (Potassium permanganate)✓
• D. H2O2 (Hydrogen peroxide)

Explanation: Potassium permanganate (KMnO4) is used as its own indicator because it changes color distinctly at the endpoint of a titration in an acidic medium. The intense purple color of KMnO4 fades to colorless (or a very faint pink) as it is reduced, providing a clear visual cue without the need for an additional indicator. In contrast, K2Cr2O7, Iodine, and H2O2 lack such a distinct color change when used in acidic conditions, making them unsuitable as self-indicators.

Q104. The atomic number of scandium is 21. What is its ground state electronic configuration?

• A. 1s22s22p63s23p63d3
• B. 1s22s22p63s23p63d14s2✓
• C. 1s22s22p63s23p63d34s2
• D. 1s22s22p63s23p63d34p1

Explanation: The electronic configuration of an atom is determined by the Aufbau Principle, which states that electrons fill the lowest energy orbitals first. For scandium, with an atomic number of 21, the correct ground state configuration is 1s22s22p63s23p63d14s2. This configuration fills the 4s orbital before starting to fill the 3d orbital, in accordance with the energy order of orbitals. The other options incorrectly fill the orbitals or suggest an incorrect order of electron filling, which does not represent the lowest energy, most stable configuration.

Q105. The centre of porphyrin ring of haemoglobin is occupied by:

• A. Magnesium
• B. Sodium
• C. Iron✓
• D. Potassium

Explanation: Hemoglobin is a protein in red blood cells responsible for oxygen transport. The core of its porphyrin ring, known as the heme group, contains iron. This iron atom binds oxygen, facilitating its transport throughout the body. Magnesium is central to chlorophyll in plants, while sodium and potassium are electrolytes not involved in the porphyrin structure of hemoglobin.

Q106. 40.0 dm3 of an ideal gas at 250C and 750 mm Hg is expanded to 50.0 dm3. The pressure of the gas changed to 765 mm Hg. What is the temperature of the gas?

• A. (298)(750)(50)/(40)(765)
• B. (298)(750)(40)/(50)(765)
• C. (298)(765)(50)/(750)(40)✓
• D. (40)(750)/(298)(50)(765)

Explanation: PV=nRTAccording to the ideal gas equation: PV = nRT. P1V1/T1=P2V2/T2 OrT2=P2V2T1/ P1V1 So T2 Should be solved as follows T2 =765*50*298/750*40

Q107. Premature death of plants is caused by the deficiency of:

• A. Magnesium✓
• B. Iron
• C. Phosphorus
• D. Potassium

Explanation: The correct answer is Magnesium. Magnesium is a critical component of chlorophyll, and its deficiency leads to chlorosis—a condition where leaves turn yellow due to insufficient chlorophyll production. This can severely affect photosynthesis, leading to premature death in plants if not corrected. While iron deficiency also causes chlorosis, it does not usually lead to premature death unless it is severe and prolonged. Phosphorus and potassium deficiencies impact other aspects of plant growth and health, but they do not directly lead to premature death.

Q108. Which electronic sub-shell do the lanthanides have incompletely filled?

• A. 3f
• B. 4f✓
• C. 5f
• D. 6f

Explanation: The lanthanides are characterized by their incompletely filled 4f sub-shells. They range from lanthanum (atomic number 57) to lutetium (atomic number 71). The 4f sub-shell can hold up to 14 electrons, and the lanthanides progressively fill this sub-shell. The 3f sub-shell does not exist, the 5f sub-shell is associated with actinides, and the 6f sub-shell is hypothetical and not part of any known series.

Q109. A wire has a resistance 'R‘. If its length is doubled and radius is reduced to half then its resistance will become:

• A. 2R
• B. 4R
• C. 8R✓
• D. 16R

Explanation: To determine the new resistance, use the formula Resistance = resistivity × length/area. When the length is doubled, the resistance is also doubled (2R). Reducing the radius to half causes the cross-sectional area (πr²) to become one quarter, which increases the resistance by a factor of four (4R). Therefore, the new resistance is 2 × 4 = 8R. Options 2R and 4R underestimate the effect of reducing the radius, while 16R overestimates it.

Q110. How many different values can m, assume in the electron sub-shell designated by quantum number n=5, l=4?

• A. 4
• B. 5
• C. 6
• D. 9✓

Explanation: 'n' is referred to as the principal quantum number and 'l' is the azimuthal quantum number. l=4 means the azimuthal quantum number is associated with 5g. Since 'g' has 9 subshells 'm' will be -4, -3, -2, -1, 0, +1, +2, +3, +4.

Q111. Which of the following is Hypochlorous acid?

• A. HCIO✓
• B. HCIO2
• C. HCIO3
• D. HCIO4

Explanation: a) HCIO (Hypochlorous acid):This is the correct option. Hypochlorous acid (HCIO) is a weak acid with the chemical formula HClO. It is formed when chlorine gas (Cl2) dissolves in water, and it is the active component responsible for the disinfectant properties of chlorine-containing solutions, such as bleach.

Q112. If 20.0 cm3 of 0.5 M solution is diluted to 1.0 dm3. What will be its new concentration?

• A. 0.001 M
• B. 0.01 M✓
• C. 1.0 M
• D. 10.0 M

Explanation: To find the new concentration after dilution, use the formula M1V1 = M2V2. Here, M1 is the initial concentration (0.5 M), V1 is the initial volume (20.0 cm3 or 0.02 dm3), and V2 is the final volume (1.0 dm3). Solving for M2 gives us M2 = (0.5 M * 0.02 dm3) / 1.0 dm3, resulting in a concentration of 0.01 M. The other options are incorrect because they either assume incorrect calculations or misunderstand the concept of dilution.

Q113. Which one of the following oxides exhibit amphoteric properties?

• A. K2O
• B. MgO
• C. ZnO✓
• D. CaO

Explanation: Zinc oxide (ZnO) is the correct answer because it is an amphoteric oxide. Unlike simple basic oxides, amphoteric oxides can react with both acids and bases. ZnO reacts with acids like hydrochloric acid to form zinc chloride (ZnCl2) and with bases like sodium hydroxide to form sodium zincate (Na2ZnO2). In contrast, K2O, MgO, and CaO are all basic oxides because they only react with acids and not with bases.

Q114. Which one of the following salts will produce an alkaline solution when dissolved in water?

• A. NH4Cl
• B. NaNO3
• C. Na2CO3✓
• D. Na2SO4

Explanation: The correct answer is Na2CO3. Sodium carbonate forms an alkaline solution because it undergoes hydrolysis in water, releasing hydroxide ions (OH-) which increase the pH. In contrast:NH4Cl forms an acidic solution due to ammonium ions generating hydronium ions.NaNO3 remains neutral as neither ion affects pH significantly.Na2SO4 also results in a neutral solution for similar reasons to NaNO3.

Q115. A neutral atom A has the electronic configuration: 1s2 2s2 2p6 3s2 3p6 4s1. It will gain or lose electron/s to form most probably an ion of valence:

• A. -2
• B. -1
• C. +2
• D. +1✓

Explanation: The element with atomic number 19 is potassium (K) which is a group 1 metal. Hence it loses one electron to form the ion valence of K+1. Therefore the answer will be D.

Q116. Which statement correctly describes a nucleon?

• A. Any atomic nucleus
• B. A radioactive atomic nucleus
• C. A neutron or a proton✓
• D. A neutron proton or an electron

Explanation: A nucleon is either a proton or a neutron, which are the subatomic particles found in the nucleus of an atom. They are held together by the strong nuclear force, which overcomes the repulsive forces between the positively charged protons. This binding is crucial for the stability and mass of the atom. The other options are incorrect: 'Any atomic nucleus' describes a region, not the specific particles; 'A radioactive atomic nucleus' refers to the behavior of the nucleus, not the definition of nucleons; and 'A neutron proton or an electron' includes an electron, which is not part of the nucleus.

Q117. Ozone gas is:

• A. Greenish, tasteless and light
• B. Greenish blue, bitter in taste
• C. Blue. Poisonous and explosive✓
• D. Purple yellow, non poisonous, non explosive

Explanation: Ozone gas is pale blue,it is a toxic substance and can lead to explosive destruction when concentrated and a trigger is applied, therefore the answer will be C.

Q118. Which one of the following is a lewis acid?

• A. (CH3)3N
• B. PH3
• C. BF3✓
• D. O2

Explanation: The correct answer is BF3 because it is an electron-deficient molecule with the ability to accept electron pairs, making it a Lewis acid. In contrast, (CH3)3N and PH3 are Lewis bases, as they possess lone pairs that can be donated. O2 is neither a Lewis acid nor a base because it is a stable molecule without the capability to accept or donate electron pairs in the context of Lewis acid-base reactions.

Q119. According to molecular orbital theory, which one of the following will indicate two unpaired electrons?

• A. N2
• B. O2✓
• C. F2
• D. He22+

Explanation: The correct answer is O2. According to molecular orbital theory, O2 has a configuration with two unpaired electrons in the π* 2p molecular orbitals, making it paramagnetic. In contrast, N2 and F2 have all paired electrons, making them diamagnetic. He22+ is a hypothetical species and unlikely to have unpaired electrons.

Q120. Which one of the following compounds will show covalent bonding?

• A. CaF2
• B. MgO
• C. KCI
• D. H2✓

Explanation: Covalent bond is a chemical bond that involves the sharing of electrons,options A, B and C all show ionic bonds, therefore the correct answer will be D.

Q121. Which one of the following has a covalent bonding by the overlap of sp hybridised orbital with p orbital?

• A. BF3
• B. H2O
• C. BeCl2✓
• D. NH3

Explanation: The correct answer is BeCl2. In BeCl2, beryllium undergoes sp hybridization, resulting in two sp hybrid orbitals that overlap with the p orbitals of chlorine atoms to form covalent bonds. This involves the overlap of sp hybridized orbitals with p orbitals.BF3 involves sp2 hybridization, not sp, and forms bonds with p orbitals of fluorine. H2O involves sp3 hybridization and does not have sp-p overlap. NH3 also involves sp3 hybridization and lacks sp-p overlap.

Q122. Four gas molecules have the speed 8.0 ms-1, 6.0 ms-1, 6.0 ms-1 and √120 ms-1 . What is their root-mean-square speed?

• A. 8.0 ms-1✓
• B. 6.0 ms-1
• C. 5.0 ms-1
• D. 7.0 ms-1

Explanation: To find the root-mean-square (RMS) speed of the gas molecules, use the formula:Vrms = √((v1^2 + v2^2 + v3^2 + v4^2) / total number of molecules)Substituting the given speeds, we calculate: Vrms = √((8.0^2 + 6.0^2 + 6.0^2 + (√120)^2) / 4) = √((64 + 36 + 36 + 120) / 4) = √(256 / 4) = √64 = 8.0 ms-1.However, the correct calculation is actually: Vrms = √((64 + 36 + 36 + 120) / 4) = √(64 + 36 + 36 + 120) / 4 = √64 = 8.0 ms-1, demonstrating the initial explanation was incorrect.Option A is correct because when calculated accurately, the RMS speed comes out to be 8.0 ms-1.

Q123. Considering the standard reduction chart, the strong reducing agent value is:

• A. Small negative values
• B. Large negative values✓
• C. Small positive values
• D. Large positive values

Explanation: The correct answer is Large negative values. A strong reducing agent has a large negative standard reduction potential. This implies that it readily donates electrons, making it effective in reducing other substances. In contrast, small negative values suggest a lesser tendency to donate electrons, while positive values, whether large or small, indicate a preference for gaining electrons, characteristic of oxidizing agents.

Q124. You are required to test the presence of NH4+ Ion in water. Which of the following reagent will solve your problem?

• A. Imethylglyoxime
• B. Tollen‘s reagent
• C. Nessler‘s reagent✓
• D. Magneson reagen

Explanation: Nessler’s reagent can be used to detect the presence of NH4+ ions in water as brown ppt is formed. Therefore the correct answer will be C.

Q125. The variable oxidation states of transition elements is attributed to the involvement of ns as well as:

• A. Unpaired d Electrons✓
• B. Unpaired p electrons
• C. Unpaired f electrons
• D. Paired up d electrons

Explanation: Transition elements exhibit variable oxidation states due to the involvement of their ns and (n-1) d electrons. The unpaired d electrons can participate in bonding through their ability to be removed or shared, leading to different oxidation states. In contrast, unpaired p and f electrons are not significant in this context. Paired d electrons are stable and do not contribute to the variability in oxidation states.

Q126. A sample of carbon-12 has a mass of 3.0 g. Which expression gives the number of atoms in the sample? (NA is the symbol of the Avogadro costant)

• A. 0.0030 NA
• B. 0.25 NA✓
• C. 3.0 NA
• D. 4.0 N A

Explanation: The number of atoms in a sample can be determined by first calculating the number of moles using the formula: Number of moles = Mass / Molar mass. For carbon-12, the molar mass is 12 g/mol, so the number of moles in a 3.0 g sample is 3/12 = 0.25 moles. The number of atoms is then found by multiplying the number of moles by Avogadro's constant (NA), which gives 0.25 NA. Therefore, option B is correct.Option A incorrectly calculates the moles, leading to a wrong number of atoms. Option C incorrectly assumes that mass in grams is equivalent to moles, and Option D makes an incorrect calculation of moles.

Q127. In contact process for the manufacture of sulphuric acid, sulphur trioxide is dissolved in sulphuric acid in form oleum. Oleum moleculr formula is:

• A. H2S2O3
• B. H2S2O5
• C. H2S2O6
• D. H2S2O7✓

Explanation: The correct answer is H2S2O7, which represents oleum. Oleum is formed when sulfur trioxide (SO3) is dissolved in sulfuric acid (H2SO4), resulting in the molecular formula H2S2O7. The other options are incorrect because they either represent non-existent or unrelated compounds.

Q128. Ethylene diamine tetra acetate ion (EDTA) is a polydentate ligand, it bonds to central metal atom through:

• A. Two of its atoms
• B. Three of its atoms
• C. Four of its atoms
• D. Six of its atoms✓

Explanation: When this ion bonds to a metal atom, the two N atoms, and four of the O atoms, are used. In this complex, a single EDTA4- ion forms 6 bonds to the Fe atom (i.e., 2 Fe-N bonds and 4 Fe-O bonds). The coordination number of 6 results in an octahedral structure.

Q129. Half cell reaction standard reduction potential, Eo=Fe2+ 2e- → Fe –0.41Cu2+ 2e- → Cu 0.34Ni2+ 2e- → Ni -0.25Zn2+ 2e- → Zn -0.76Referring to the table above which metal could be used to prevent iron from corrosion?

• A. Cu only
• B. Zn only✓
• C. Cu & Ni only
• D. Ni and Zn only

Explanation: The correct answer is Zn only. Zinc has a standard reduction potential of -0.76 V, which is more negative than iron's -0.41 V. This makes zinc an effective sacrificial anode, as it will oxidize before iron, thus protecting it from corrosion. Copper and nickel have higher (less negative) reduction potentials than iron, making them unsuitable for this purpose. Therefore, only zinc can provide the necessary protection.

Q130. Lipids are naturally occurring substances which are chemically:

• A. Proteins
• B. Amino acids
• C. Carbohydrates
• D. Esters✓

Explanation: Lipids are predominantly made up of fatty acids and glycerol. The ester bond formed between these components categorizes lipids as esters. This chemical structure is essential for their role in energy storage, insulation, and cell membrane formation. The other options, such as proteins, amino acids, and carbohydrates, represent different classes of biomolecules with distinct structures and functions. Proteins are polymers of amino acids, carbohydrates are simple sugars or complex polymers like starch, and amino acids are the monomers that constitute proteins.

Q131. A salt AB ionizes as AB = A+ > B- .The solubility product for the salt AB is 4.0 x 10-4. The molar solubility of the salt is:

• A. 4.0 x 10-4 M
• B. 2.0 x 10-2 M✓
• C. 8.0 x 10-4 M
• D. 2.0 x 10-4 M

Explanation: The solubility product (Ksp) of a salt AB that ionizes as AB = A+ + B- is given as 4.0 x 10-4. For a salt that dissociates in a 1:1 ratio, the Ksp expression is [A+][B-] = x2, where x represents the molar solubility. Solving for x, we find that x = √(4.0 x 10-4) = 2.0 x 10-2 M, which is option B. The other options are incorrect because they either confuse the Ksp value as the molar solubility or incorrectly perform the square root calculation.

Q132. The primers used in polymerase chain reaction has a sequence of bases

• A. 8
• B. 12
• C. 16
• D. 20✓

Explanation: Primers in PCR are typically designed to be 18-22 bases long. This length allows them to bind specifically to the target DNA sequence, providing both high specificity and efficiency at the annealing temperature. Options A, B, and C (8, 12, and 16 bases, respectively) are generally too short to offer the necessary specificity and might lead to non-specific binding or inefficient amplification. Therefore, option D, 20 bases, is the correct choice as it falls within the optimal range for PCR primer design.

Q133. Which one is least reactive towards reaction with Na?

• A. HCOOH (Formic Acid)
• B. CH3CH2COOH (Propanoic Acid)
• C. CH3OCH3 (Diethyl Ether)✓
• D. CH3COOH (Acetic Acid)

Explanation: The correct answer is CH3OCH3 (Diethyl Ether). Diethyl ether does not contain an active hydrogen atom that sodium can displace, unlike carboxylic acids such as formic acid (HCOOH), propanoic acid (CH3CH2COOH), and acetic acid (CH3COOH). These acids have a hydrogen atom in their carboxyl group that reacts with sodium to release hydrogen gas, making them more reactive than diethyl ether when reacted with sodium.

Q134. The element which has the smallest atomic radius is

• A. Fe
• B. Co
• C. Ni
• D. Cu✓

Explanation: Atomic radius decreases across a period since all these elements belong to the same period of the d-block, copper is the last element in the period amongst these elements. Hence it has the smallest atomic radius.

Q135. Which one of the following has negative temperature coefficient?

• A. Copper
• B. Thermistor✓
• C. Soft iron
• D. Platinum

Explanation: NTC, negative thermistors are resistors with a negative temperature coefficient which means the resistance decreases with increasing temperature. Hence the answer will be B.

Q136. Pulvinus tissues are present at:

• A. Leaf-tip
• B. Leaf-margin
• C. Leaf-base✓
• D. Middle-vein

Explanation: Pulvini may be present at the base or apex of the petiole, they consist of a core of vascular tissue within a flexible, bulky cylinder of thin walled parenchyma cells. Therefore the correct answer will be C.

Q137. Which isomers have difference in both their physical and chemical properties?

• A. Chain isomers
• B. Position isomers
• C. Functional group isomers✓
• D. Both (A) and (B)

Explanation: Functional group isomers differ in the functional groups within their structures, leading to distinct chemical reactions and variations in physical properties such as boiling and melting points. On the other hand, chain isomers vary mainly in the carbon skeleton arrangement, affecting physical properties to a lesser extent and minimally influencing chemical behavior. Position isomers have different locations of functional groups within the molecule, which might slightly vary physical attributes but rarely chemical properties. Thus, functional group isomers are unique in their significant differences in both physical and chemical properties.

Q138. Which of the following tests can be used to distinguish between aldehydes and ketone?

• A. Bacyer‘s test
• B. Fehling‘s test
• C. Silver mirror test
• D. Both (B) and (c)✓

Explanation: Both fehling’s test and silver mirror test also known as tollens’ test is used to distinguish between aldehydes and ketones. The correct answer will be D.

Q139. One way of expressing the equation of state for an ideal gas is by the equation pV = NkT. What do 'N‘ and 'K‘ represent respectively

• A. Avogadro constant; Boltzmann constant
• B. Avogadro constant; Molar gas constant
• C. Total number of molecules; Boltzmann constant✓
• D. Total number of molecules; Avogadro constant

Explanation: In the ideal gas equation pV = NkT, 'N' represents the total number of molecules of gas, while 'k' represents the Boltzmann constant. The other options are incorrect because 'N' does not represent Avogadro's constant or the molar gas constant, and 'k' is not the Avogadro constant.

Q140. On the ground, the gravitational force on a satellite is W. What is the gravitational force on the satellite when at a height R/50, where R is the radius of the earth?

• A. 1.04W
• B. 1.02W
• C. 0.50W
• D. 0.96W✓

Explanation: Gravitational force has formula,F=GMm/R2Where G is constant, M is mass of earth ,m is mass of object and R is distance between earth's center and objectOn ground Force= GMm/R2Because distance equals to radius of earthIn given orbit,Force=GMm/(R+R/50)²Taking LCM of R+R/50, we get 51R/50GMm/(51R/50)²GMm/(2601 R²/2500)= GMmx2500/2601R²Equating both these equations:GMm x 2500/2601R²=GMm/R2All the constants will be canceled and we will be left with;2500/2601 = 0.96WSo right option will be D

Q141. If a wave can be polarized, it must be:

• A. An electromagnetic wave
• B. A stationary wave
• C. Transverse wave✓
• D. A longitudinal wave

Explanation: Transverse waves which include all electromagnetic waves such as light, radio waves, and x-rays can be polarized, hence the answer will be C.

Q142. In the nuclear reaction shown below what is the value of the coefficient?92U235+ 0n1_ = 56Kr89+γon1 + 200MeV

• A. 0
• B. 1
• C. 2
• D. 3✓

Explanation: In the fission reaction, uranium absorbs a neutron and forms a barium and krypton nucleus which are extremely unstable and they instantaneously release three neutrons between themselves becoming barium144 and krypton89, therefore the answer is option D.Option A is incorrect because a neutron is always produced in fission reactions. Option B is incorrect because fission reactions usually release around 2-3 neutrons, not just one. Option C is incorrect because the fission of U-235 typically releases 2 or 3 neutrons, not just two.

Q143. The vectors A and B are such that |A + B| = |A – B|, then the angle between the two vectors is:

• A. 00
• B. 600
• C. 900✓
• D. 1800

Explanation: Consider the angle between A and B as ∅. The resultant of A + B vector is R = √(A²+B²+2AB cos∅) and the resultant of A - B vector is R = √(A²+B²-2AB cos∅). Given |A+B| = |A-B|, we can equate the expressions and solve for cos∅ to find ∅ = 90°. This is the correct angle between the vectors based on the provided equation.The other options are incorrect because they do not align with the properties of vector magnitudes and the equation given. Option A and D provide angles that are not supported by the equation, and Option B is based on a misinterpretation of the cosine function in this context.

Q144. A zirconium nucleus is a ß-emitter. The product nucleus is also a ß-emitter. What is the final resulting nucleus of these two decays?

• A. 100Sr38
• B. 100Mo42✓
• C. 98Zr40
• D. 100Zr40

Explanation: In beta decay, the atomic number increases by 1 for each decay. Since there are 2 beta decays, the atomic number increases by 2, resulting in the final nucleus being Mo-100. This is why option B is correct. Option A, C, and D are incorrect because they do not account for the increase in the atomic number during beta decay.

Q145. A racing car accelerates uniformly through three gear changes with the following average speeds:20 ms-1 for 2.0s ;40ms-1 for 2.0 s and 60 ms-1 for 6.0s. What is the overall average speed of the car?

• A. 12 ms-1
• B. 13.3 ms-1
• C. 40 ms-1
• D. 48 ms-1✓

Explanation: To find the overall average speed, we use the formula: Average speed = Total distance / Total time. First, calculate the individual distances traveled during each gear change:For the first gear change: Distance = 20 ms-1 x 2 s = 40 mFor the second gear change: Distance = 40 ms-1 x 2 s = 80 mFor the third gear change: Distance = 60 ms-1 x 6 s = 360 mThe total distance is 40 m + 80 m + 360 m = 480 m. The total time is 2 s + 2 s + 6 s = 10 s. Thus, the overall average speed is 480 m / 10 s = 48 ms-1, making Option D the correct answer.Options A, B, and C are incorrect because they do not correctly apply the formula for average speed, either due to incorrect calculations or by using incorrect values.

Q146. Which of the following lists contains scalar quantities only?

• A. Mass, acceleration, temperature, kinetic energy
• B. Mass, volume, electrical potential, kinetic energy✓
• C. Acceleration, temperature, volume, electric charge
• D. Momentum, electric intensity, density, magnetic flux.

Explanation: A scalar quantity contains only magnitude and no direction, making options B the correct answer. Mass, volume, and electrical potential are all examples of scalar quantities as they can be fully described by their magnitude alone. Kinetic energy is also a scalar quantity due to the mathematical relationship between mass and velocity. Options A, C, and D include vector quantities, such as acceleration, momentum, and electric intensity, which have both magnitude and direction, making them incorrect choices for this question.

Q147. A generator produces 100 kW of power at a potential difference of 10KV. The power is transmitted through cables of total resistance 5Q. How much power is dissipated in the cables?

• A. 50 W
• B. 750 W
• C. 500 W✓
• D. 1000 W

Explanation: To find the power dissipated in the cables, you need to first calculate the current flowing through the circuit. The power produced by the generator is 100 kW, which is equal to 100,000 W, and the potential difference is 10 kV, equal to 10,000 V. Using the formula P = VI, where P is power, V is voltage, and I is current, you can solve for current:I = P / V = 100,000 W / 10,000 V = 10 A.Now, using the formula for power dissipation in the cables, P = I²R, where I is the current (10 A) and R is the resistance of the cables (5 ohms), you calculate:P = 10² x 5 = 100 x 5 = 500 W.Therefore, 500 W of power is dissipated in the cables.Options A (50 W), B (750 W), and D (1000 W) are incorrect as they do not result from the correct application of the power loss formula I²R with the calculated current.

Q148. Read the statement and choose the option correctly.

• A. Option A✓
• B. Option B
• C. Option C
• D. Option D

Explanation: The general form of a rate law is: Rate =k[A]x[B]y1. Find the effect of changing [A] (Order with respect to A):Compare Experiment 1 and Experiment 2.In Experiment 1: [A]=0.1, [B]=0.1, Rate =2×10−5In Experiment 2: [A]=0.2, [B]=0.1, Rate =4×10−5Notice that [B] stays the same (0.1).When [A] doubles (from 0.1 to 0.2), the Rate also doubles (from 2×10−5 to 4×10−5).If doubling the concentration doubles the rate, the reaction is first order with respect to A. So, x=1.2. Find the effect of changing [B] (Order with respect to B):Compare Experiment 1 and Experiment 3.In Experiment 1: [A]=0.1, [B]=0.1, Rate =2×10−5In Experiment 3: [A]=0.1, [B]=0.2, Rate =4×10−5Notice that [A] stays the same (0.1).When [B] doubles (from 0.1 to 0.2), the Rate also doubles (from 2×10−5 to 4×10−5).If doubling the concentration doubles the rate, the reaction is first order with respect to B. So, y=1.3. Combine to find the Rate Law: Since x=1 and y=1, the rate law is: Rate =k[A]1[B]1 Which simplifies to: Rate =k[A][B]

Q149. Ultraviolet rays differ from the X-rays such that ultraviolet rays _

• A. Cannot be diffracted
• B. Cannot be polarized
• C. Have a low frequency✓
• D. Do not affect a photographic plate

Explanation: Option C is correct

Q150. if a body of mass M is released in a vacuum just above the surface of planet of mass M and radius R what would be its gravitational acceleration

• A. GMm/R
• B. GMm/R 2
• C. GM/R2✓
• D. GM/R2

Explanation: If a body of mass M is released just above the surface of a planet of mass M and radius R in a vacuum, the gravitational acceleration experienced by the falling body can be calculated using Newton's law of universal gravitation and the formula for gravitational acceleration:GM/R2

Q151. The first law of thermodynamics is a statement which implies that:

• A. No heat enters or leaves the system
• B. The temperature remains constant
• C. All work is mechanical
• D. Energy is conserved✓

Explanation: The first law of thermodynamics states that energy can neither be created nor destroyed, it is converted from one form to another, therefore the answer will be D

Q152. The function of a main transformer is to convert:

• A. one direct voltage to another direct voltage of different magnitude.
• B. one alternating voltage to another alternating voltage of different magnitude.✓
• C. a high value alternating voltage to low value direct voltage.
• D. A high value alternating current to low value direct voltage

Explanation: A transformer converts a high voltage low current alternating current to a low voltage high current one and vice versa. Therefore the answer will be B.

Q153. When monochromatic light of wavelength 5.0X 10-7 m is incident normally on a plane diffraction grating, the second order diffraction lines are formed at angles of 300 to the normal to the grating. What is the number of lines per millimeter of the grating?

• A. 250
• B. 500✓
• C. 1000
• D. 4000

Explanation: To solve this problem, we use the formula for diffraction grating: d sin(θ) = nλ, where d is the grating spacing, θ is the angle of diffraction, n is the order of diffraction, and λ is the wavelength.Given: λ = 5.0 × 10-7 m, θ = 30°, and n = 2.Substitute these values into the formula to find d: d = nλ / sin(θ) = (2 × 5.0 × 10-7) / 0.5 = 2 × 10-6 m.The number of lines per meter is the reciprocal of d: N = 1/d = 1/(2 × 10-6) = 500,000 lines/m.Converting to lines per millimeter: N = 500,000 / 1,000 = 500 lines/mm.Therefore, Option B is correct. The other options result from incorrect calculations or misunderstandings of the formula.

Q154. During the experiment, one measured the mass of mosquito and found it 1.20x 10-5 kg. The number of significant figures in this case is:

• A. 3 s.f✓
• B. 2 s.f
• C. 5 s.f
• D. 8 s.f

Explanation: When determining the number of significant figures in a measurement, focus on the digits that are known with certainty and the first estimated digit. In this case, the mass of the mosquito was measured as 1.20 × 10^-5, with the digits 1, 2, and the exponent -5 being certain and therefore significant. The leading zero is not significant. Therefore, the correct answer is 3 significant figures.

Q155. If a hole is bored through the center of the earth and a pebble is dropped in it, then it will:

• A. Stop at the center of the earth
• B. Drop to the other side
• C. Execute SHM✓
• D. None of the above.

Explanation: The pebble would fall down to the other side and in a ideal situation would oscillate between the two ends in simple harmonic motion. Therefore the answer would be C.

Q156. The minimum frequency of incident light required to emit photoelectrons from the metal surface is called:

• A. Critical frequency
• B. Threshold frequency✓
• C. Work function
• D. None of the above

Explanation: This minimum frequency is also called the threshold frequency, and the value of ν0​\nu, start subscript, 0, end subscript depends on the metal. For frequencies greater than ν0​\nu, start subscript, 0, end subscript, electrons would be ejected from the metal.

Q157. If two cars are moving with velocity 10 m/s and 5m/s in opposite direction to each other, then their relative velocity with respect to one another will be:

• A. 5m/s
• B. 10m/s
• C. -5m/s
• D. 15m/s✓

Explanation: The relative velocity of the two cars with respect to one another can be found by adding their velocities. Since they are moving in opposite directions, we need to subtract the velocity of one car from the other: Relative velocity = velocity of first car - velocity of second car = 10 m/s - (-5m/s) = 10 m/s + 5 m/s = 15 m/s

Q158. When released from a height a ball falls 5m in 1s. In 4s after release the ball will fall:

• A. 40m
• B. 80m✓
• C. 20m
• D. 100m

Explanation: Since,s = ut + ½ at²u = 0, a = gt = 4sg ≈ 10 ms-²Then,s = (0)(4) + ½ (10)(4)²s = 0 + ½ (10)(16)s = ½ (160)s = 80m

Q159. Select the correct in direct speech:"I saw him yesterday," she said.

• A. She told that she had seen him yesterday
• B. She said that she had seen him the day before✓
• C. She told that she could see him the previous day
• D. She said that she would see him the day before

Explanation: Option (b), "She said that she had seen him the day before," is the correct choice. It correctly changes the past simple "saw" to the past perfect "had seen," and it also shifts "yesterday" to "the day before," which is appropriate for indirect speech.

Q160. If the momentum of a body decreases by 20% the percentage decrease in K.E will be:

• A. 44%
• B. 36%✓
• C. 28%
• D. 20%

Explanation: Momentum p = mvIf momentum is decreased by 20%, the resulting new value is 80% of the original p-p'P - 0.2p = mv - m0.2vP - 0.2p = (m) (v) (0.8)K.E = ½ mv²= ½ m (0.64v²)K.E = 36%

Q161. The antimatter of election is:

• A. Photon
• B. Roton
• C. Positron✓
• D. Antineutrino

Explanation: Antimatter is a type of matter made up of antiparticles. A positron is the antiparticle of an electron, making it the correct answer. Photons and rotons do not have antimatter counterparts, and antineutrinos are not directly related to electron processes.

Q162. An organ pipe is open at both ends at its fundamental frequency. Neglecting any end effects, what wavelength is formed by this pipe in this mode of vibration, if the pipe is two meter long?

• A. 2m
• B. 4m✓
• C. 6m
• D. 8m

Explanation: For an open pipe at both ends, the fundamental frequency is given by: f = v/2LWhere v is the speed of sound and L is the length of the pipe.We can rearrange this equation to solve for the wavelength (λ): λ = 2LSubstituting the given value of L = 2m, we get: λ = 2 (2) = 4mTherefore, the wavelength formed by this pipe in its fundamental frequency is 4m.

Q163. A body in equilibrium must not have:

• A. Kinetic energy
• B. Velocity
• C. Momentum
• D. Acceleration✓

Explanation: For a body to be in equilibrium, it must have zero net acceleration, which is the result of all external forces canceling each other out. This ensures that the body does not change its state of motion. While kinetic energy, velocity, and momentum can exist, they must remain constant, indicating no net external force is present. Acceleration, however, signifies a change in the state of motion due to a net force, which contradicts the condition of equilibrium.

Q164. The differences in energy between different states of bond vibrations in a molecule correspond to which electromagnetic region?

• A. Microwave
• B. Infrared✓
• C. Visible
• D. X-rays

Explanation: The difference in energy between two vibrational states is equal to the energy associated with the wavelength of radiation that was absorbed, it lies in the infrared region, therefore the answer is B.

Q165. Three equivalent resistors connected in parallel have equivalent resistance R/3. When they are connected in series then the equivalent resistance is:

• A. 3R✓
• B. R/3
• C. R
• D. 2R

Explanation: When three equivalent resistors are connected in parallel, the equivalent resistance is 3/R. When these same resistors are connected in series, their resistances add up, resulting in an equivalent resistance of 3R. Therefore, the correct option is 3R. Options B, C, and D are incorrect because they do not align with the calculations for equivalent resistance in parallel and series resistor connections.

Q166. Ohm‘s law is valid only for

• A. Thermistor
• B. Bulb filament
• C. Metals✓
• D. Semiconductors

Explanation: Ohm's law is valid for metallic conductors because they have a linear relationship between current and voltage. This makes Option C, 'Metals', the correct answer. Thermistors, bulb filaments, and semiconductors do not follow this linear relationship and hence Ohm's law is not valid for them.

Q167. Which of the given formulae would be used to calculate the wavelength of an electron? Given its velocity(v), its mass (m) and constant h:

• A. v = f.λ
• B. λ = h / mv✓
• C. s = d/t
• D. p = λ x h

Explanation: The correct formula to calculate the wavelength of an electron is λ = h / mv, known as De Broglie's wave equation. This equation takes into account Planck's constant (h), the mass of the electron (m), and its velocity (v). Option B is correct because it correctly represents this calculation. Options A, C, and D are incorrect as they represent formulas for velocity, speed, and momentum, respectively, not wavelength.

Q168. The energy stored in a charged capacltor is given by:

• A. 1/2 CV2
• B. 1/2 QV
• C. 1/2 m v2
• D. Both A and B✓

Explanation: The correct answer is Option D: Both A and B. The energy stored in a charged capacitor can be represented by the formulas E = 1/2 CV² or E = 1/2 QV. Option A and B both correctly represent the energy stored in a charged capacitor. Option C is incorrect as 1/2 mv² is the formula for kinetic energy, not the energy stored in a capacitor.

Q169. The potential difference between a pair of similar and parallel conducting plates is known. What additional information is needed in order to find the electric field strength between the plates?

• A. Separation of the plates✓
• B. Separation and area of the plates
• C. Permittivity of the medium; separation of the plates
• D. Permittivity of the medium; separation and area of the plates

Explanation: The correct answer is Option A: Separation of the plates. The electric field strength between parallel conducting plates can be calculated using the formula E = V/d, where V is the potential difference and d is the distance between the plates. Therefore, knowing the separation of the plates is the additional information needed to determine the electric field strength in this scenario.Options B, C, and D include unnecessary information such as the area of the plates and permittivity of the medium, which are not directly required to find the electric field strength between the plates.

Q170. A capacitor which has a capacitance of 1 farad (F) will:

• A. Be fully charged in 1 second by a current of 1 Ampere
• B. Store 1 coulomb of charge at potential difference of 1 volt✓
• C. Gain 1 joule of energy when 1 coulomb of charge is stored on it
• D. Discharge in 1 second when connected across a resistor of resistance 3 ohms

Explanation: A capacitance of 1F produces 1V of potential difference for an electric charge of one coulomb (1C). This statement also fully agrees with the formula C=Q/V.

Q171. The internal energy of a fixed case of an ideal gas depends on:

• A. Pressure, but not volume or temperature
• B. Temperature, but not pressure or volume✓
• C. Volume, but not pressure or temperature
• D. Pressure and temperature, but not volume

Explanation: In an ideal gas the inter-molecular collisions are assumed to be absent and the collisions are perfectly elastic, thus, the gas only possesses kinetic energy and hence the internal energy of the ideal gas only depends on temperature,hence the answer will be B.

Q172. A spring obeying Book‘s law has an unstretched length of 50 mm and a spring contant of 400 Nm-01. What is the tension in the spring when its overall length is 70mm?

• A. 8.0N✓
• B. 28N
• C. 160N
• D. 400N

Explanation: According to Hooke's Law, the force F exerted by a spring is directly proportional to the displacement x from its equilibrium position, which can be expressed as F = kx.In this problem, the unstretched length of the spring is 50 mm. The stretched length is given as 70 mm, so the displacement x is 70 mm - 50 mm = 20 mm, which is 0.02 meters.The spring constant k is given as 400 N/m. Therefore, the tension in the spring is F = 400 N/m * 0.02 m = 8 N.Options B, C, and D are incorrect because they either miscalculate the displacement, misapply the spring constant, or misunderstand the relationship given by Hooke's Law.

Q173. Which thermodynamic temperature is equivalent to 501.850C?

• A. 775.00 K✓
• B. 774.85 K
• C. 228.85 K
• D. 228.70 K

Explanation: To convert from Celsius (C) to thermodynamic temperature, also known as Kelvin (K), you can use the formula:Kelvin (K) = Celsius (C) + 273.15So, to find the thermodynamic temperature equivalent to 501.85°C, you can do the following calculation:Kelvin (K) = 501.85 + 273.15Kelvin (K) = 775.00 KTherefore, 501.85°C is equivalent to 775.00 K.

Q174. An object travels at constant speed around a circle of radius 1.0 m in 1.0 s. what is the magnitude of its acceleration?

• A. Zero
• B. 1.0 ms-2
• C. 2π ms-2
• D. 4π2 ms-2✓

Explanation: To find the magnitude of the acceleration of an object moving in a circle, we use the formula for centripetal acceleration: a = ω²r. In this case, the angular velocity ω is 2π rad/s because the object completes one full circle (2π radians) in 1 second. The radius r is given as 1.0 m. Substituting these values, we find that the acceleration a = (2π)²(1) = 4π² ms-2.The other options are incorrect because they either assume no acceleration (which ignores the change in direction), or they use incorrect calculations or interpretations of the formula for centripetal acceleration.

Q175. An alternating current '1/A‘ varies with time 't/s‘ according to the equation I = 5sin(100πt). What is the mean power developed by the current in a resistive load of resistance 10?

• A. 125W✓
• B. 160W
• C. 250W
• D. 500W

Explanation: To find the mean power developed by the current in the resistive load, we first calculate the peak value of the current, which is 3.53. With a resistance of 10Ω, the power is determined using P = I²R = (3.53)²(10) = 125 W. The correct answer is 125W. The other options are incorrect because they do not accurately reflect the power calculated based on the values provided in the question.

Q176. The rate of change of momentum of a body falling freely under gravity is equal to its:

• A. Impulse
• B. Kinetic energy
• C. Power
• D. Weight✓

Explanation: Option D is correct. The rate of change of momentum of a body falling freely under gravity is equal to its weight. When an object is in free fall, the force of gravity is the only force acting on it, which can be expressed as its weight (mass * gravity). Therefore, according to Newton's second law, the rate of change of momentum (dp/dt) is equal to the gravitational force, synonymous with weight in this context.Why the other options are incorrect:Impulse: Although impulse is related to the change in momentum, it is not the rate of change of momentum; it is the product of force and the time during which the force acts.Kinetic Energy: Kinetic energy quantifies an object's energy due to motion but is not directly linked to the momentum change rate.Power: Power measures the rate of doing work, not the rate of change of momentum.

Q177. Radioactive activity is affected by:

• A. Temperature
• B. Pressure
• C. Humidity level
• D. None of the above✓

Explanation: Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting radiation. This process is governed by nuclear forces and is not influenced by external environmental factors such as temperature, pressure, or humidity. Therefore, the correct answer is None of the above. The other options are incorrect because they suggest that external conditions, which affect chemical reactions, also affect nuclear reactions, which they do not.

Q178. The change in enthalpy at constant pressure, △H is equal to:

• A. △H = q + P△V✓
• B. △H = △E- P△V
• C. △H = △E + P△V
• D. △H = q - P△V

Explanation: The change in enthalpy, ∆H, at constant pressure is equal to the sum of the heat absorbed or released, q, and the pressure-volume work, P∆V, done on or by the system during the process. This is because enthapy, H, is defined as the sum of internal energy, U, and the product of pressure and volume, PV, and at constant pressure, the change in enthalpy is equal to the heat transferred plus the Workdone.∆H = q + P∆V

Q179. An organ pipe of length T has one end closed but the other end open. What is the wavelength of the fundamental node emitted?

• A. 4 × T✓
• B. 2 × T
• C. 3 × T
• D. 1 × T

Explanation: The fundamental mode of a closed-open organ pipe produces a wavelength that is four times the length of the pipe. This is because the closed end is a displacement node and the open end is a displacement antinode, leading to a quarter wavelength fitting into the pipe length. Hence, the full wavelength is 4 times the pipe length, T. The other options do not account for the correct relationship between the pipe length and the wavelength in a closed-open pipe.

Q180. Which statement is correct while recharging the automobile battery?

• A. Pb is converted to PbO2
• B. PbSO4 is converted to Ph
• C. Pb is converted to PbSO4✓
• D. None of the above

Explanation: Pb oxidized to PBSO4When the battery is discharging, it acts as a galvanic cell and the following chemical reaction occurs:Negative:Pb(s) + HSO4- + H2O (l) → 2e- + PbSO4(s) + H3O+(aq)Pb is oxidized.Positive:PbO2 (s) + HSO4- (aq) + 3H3O+(aq) +2e- → PBSO4 (s) + 5H2O (l)

Q181. A vertical steel wire X of circular cross-section is used to suspend a load. A second wire Y, made of the same material but having twice the length and twice the diameter is used to suspend an equal load. What is the value of the ratio?

• A. 1/1✓
• B. 1
• C. 2
• D. 4

Explanation: Since the wires at made of the same material, their young modulus will be the same hence they have the same length, force and area. So the ratio is going to be 1/1 = 1

Q182. Drops X and Y, of the same oil, remained stationary in air in the same electric field. After the field was switched off, X fell more quickly than Y. which deduction can be made?

• A. X had a greater charge than Y✓
• B. Y had a greater charge than X
• C. Parallel but opposite
• D. Parallel, opposite and folded spirally.

Explanation: The correct answer is that X had a greater charge than Y. This conclusion is drawn from the observation that after the electric field was switched off, drop X fell more quickly than drop Y. The behavior of the drops in the electric field indicates that while the field was active, the electrostatic forces acting on each drop were balanced by the drag forces. Since X fell faster once the field was removed, it suggests that X must have had a greater charge to maintain equilibrium under the influence of the electric field. This indicates that the weight of the drops, which is proportional to the cube of their radii, was not sufficient to counteract the charge-induced forces on drop Y. Thus, drop X's greater charge allowed it to fall more rapidly once the electric field was no longer present.Other options are incorrect because they either contradict the observed behavior of the drops or are irrelevant to the relationship between the charges and the motion of the drops in the electric field.

Q183. Which of the following furnaces is used for the production of wrought iron?

• A. Open hearth furnace✓
• B. Reverberatory furnace
• C. Bessemer converter
• D. Blast furnace

Explanation: A puddling furnace is used which is a type of an open hearth furnace, it is constructed to pull hot air over the iron without the fuel coming in direct contact with the iron. Therefore the correct answer will be A.

Q184. A mass accelerates uniformily when the resultant force acting on it:

• A. Is zero
• B. Is constant but not zero✓
• C. Increases uniformly with respect to time
• D. Is proportional to the displacement of the mass from a fixed point

Explanation: A mass accelerates uniformly when the resultant force acting on it is constant but not zero.

Q185. Which of the following lists contains three regions of the electromagnetic spectrum in order of increasing frequency?

• A. Gamma rays, ultraviolet rays, radio waves
• B. Gamma rays, visible radiation, ultraviolet rays
• C. Microwaves, ultraviolet rays, X-rays✓
• D. Radio waves, visible radiation, infrared radiation

Explanation: The electromagnetic spectrum is as such as wavelength decreases frequency increases, therefore the correct answer would be C ,as the question requires in order of increasing frequencies and gamma has the highest frequency, whereas in option D infrared has a higher frequency than ultra violet.

Q186. A source contains initially N0 nuclei of a radioactive nuclide. How many of these nuclei have decayed after a time interval of three half-lives?

• A. N0/8
• B. 2N0/3
• C. N0/3
• D. 7N0/8✓

Explanation: Each half-life reduces the remaining number of nuclei by half. After one half-life, N0/2 nuclei remain. After two half-lives, N0/4 nuclei remain. After three half-lives, N0/8 nuclei remain. Therefore, the number of nuclei that have decayed is the initial amount minus the remaining amount: N0 - N0/8 = 7N0/8. Thus, Option D is correct. The other options are incorrect because they either represent the remaining amount of nuclei or an incorrect calculation of decayed nuclei.

Q187. Two monochromatic radiations X and Y are incident normally on a diffraction grating. The second order intensity maximum for X coincides with the third order intensity maximum for Y. what is the ratio wavelength of x/ wavelength of y?

• A. 1/2
• B. 2/3
• C. 3/2✓
• D. 2/1

Explanation: To determine the ratio of the wavelengths, use the diffraction grating formula: d sin θ = mλ, where d is the grating spacing, θ is the angle of diffraction, m is the order of the maximum, and λ is the wavelength.For radiation X, the second order maximum is given by 2λX. For radiation Y, the third order maximum is given by 3λY. Since these maxima coincide:2λX = 3λYRearranging gives the ratio of wavelengths: λX/λY = 3/2.Therefore, the correct answer is C. Other options do not satisfy the condition given by the coincidence of different order maxima.

Q188. A sound wave of frequency 400 Hz is travelling in a gas at a speed of 320 ms-1. What is the phase difference between two points 0.2 m apart in the direction of the travel?

• A. n/1 rad
• B. n/2 rad✓
• C. 2n/5 rad
• D. 4n/5 rad

Explanation: The phase difference between two points in a wave is given by the formula: ∆φ = 2π∆x/λ. In this case, the phase difference between points 0.2m apart can be calculated to be π/2 radians. This is because the wavelength of the sound wave is 0.8m, and the distance between the two points is 0.2m. Therefore, the correct answer is Option B. The other options are incorrect because they do not represent the accurate phase difference based on the given values.

Q189. Which of the following is the unit of pressure?

• A. Kg m s-1
• B. Kg m-1 s-2✓
• C. Kg m2 s-2
• D. Kg m-2 s-1

Explanation: Pressure is calculated as force per unit area. In this case, the correct unit of pressure is Kg m-1 s-2. This unit is derived from the formula P = F/A, where force is measured in Kg m s-2 and area in m2. This simplifies to Kg m-1 s-2, which is the unit of pressure.Option A is incorrect as it represents the unit of momentum, not pressure. Option C is also incorrect as it represents the unit of energy or work. Option D is not the unit of pressure either.

Q190. Satellites revolve around the earth in a circular orbit. What is the relationship between the radius of their orbits and their speeds?

• A. V ∞ r2
• B. V ∞ r
• C. V1 ∞ 1/r
• D. V ∞ 1/r2✓

Explanation: d) V ∞ 1/r^2 (V is proportional to 1/r^2):This option correctly represents the relationship between the speed (V) of a satellite and the radius (r) of its orbit. The speed of a satellite is inversely proportional to the square of the radius of its orbit. This means that as the radius of the orbit increases, the speed of the satellite decreases, and vice versa.

Q191. Of the following properties of a wave, the one that is independent of the others is its:

• A. Amplitude✓
• B. Wavelength
• C. Speed
• D. Frequency

Explanation: Amplitude of a wave is independent whereas speed wavelength and frequency are all depend on each other via the formulaSpeed = wavelength x frequency, hence the answer will be A.

Q192. The force 'F‘ on a charged partied 'q‘ moving with velocity ;v‘ parallel to magnetic held 'B‘ is given by:

• A. F = qvB
• B. F = qE
• C. F = 0✓
• D. F = mv2/r

Explanation: When a charged particle moves parallel to a magnetic field, the force acting on it is zero because the angle between the velocity and magnetic field is 0 degrees, resulting in sin(0) = 0. Therefore, the correct answer is Option C. Option A and Option B are incorrect as they represent formulas for different fields, while Option D is incorrect as it represents the formula for centripetal force, not magnetic force.

Q193. Select the correct indirect speech"Have you got a computer?" she said.

• A. She wanted to find a whether I have a computer
• B. She wanted to know whether I had a computer✓
• C. She wanted to know if I could use a computer
• D. She was interested to know about my computer

Explanation: Option (b), "She wanted to know whether I had a computer," is the correct choice. It accurately transforms the direct question into indirect speech by changing "have you got" to "I had," which correctly shifts the present tense to the past tense. It also maintains the original intent of asking about possession.

Q194. Add some milk and sugar _ the afternoon tea.

• A. With
• B. In
• C. On
• D. To✓

Explanation: Sure, here are sentences using each preposition:1. Use of: The use of smartphones has increased significantly in recent years.2. With: He decorated the cake with colorful icing and sprinkles.3. In: She found her keys in the drawer.4. On: Please place the book on the table.5. To: I'm looking forward to seeing you at the party.Use the preposition 'to' when indicating that there is movement from one place to another.

Q195. "Allusion‘ means:

• A. An idea haunting one‘s mind
• B. A casual or indirect reference✓
• C. Have a low frequency
• D. Do not affect a photographic plate

Explanation: Allusion is a figure of speech that involves making an indirect or passing reference to something else. Therefore, option B is correct. Options A, C, and D do not accurately define 'Allusion' and are incorrect choices for this question.

Q196. 'Get a hold of oneself ' implies:

• A. To start running
• B. To catch a thief
• C. To become calm✓
• D. To feel exhausted

Explanation: 'Get a hold of oneself' means to regain composure and control of one's thoughts and emotions, hence the correct answer is Option C. Options A, B, and D are incorrect as they do not capture the essence of regaining control and composure as the phrase implies.

Q197. Select the correct sentence:

• A. My feet seemed hardly to touch the earth.
• B. My feet hardly seamed to touch the earth.✓
• C. Hardly my feet seemed to touch the earth.
• D. My feet seemed to touch the earth hardly.

Explanation: To solve english questions, read the sentence outloud. You will eliminate all options except B since that is coherent.

Q198. In a composition writing exercise, 'Precise‘ means:

• A. A synopsis for writing an essay in a degree level examination
• B. A critique highlighting the weak point of a feature film story
• C. A resume of the commercial achievements spread over a year
• D. A short summary of the crucial ideas of a longer composition.✓

Explanation: The term 'precise' in this context refers to a concise summary that captures the key ideas of a longer composition. Option D is correct because it aligns with the definition of 'precise' as a short summary of essential points. The other options are incorrect as they do not accurately define 'precise' in the context of composition writing.

Q199. Select indirect speech"I have been to Spain," he told me.

• A. He told me that he could visit Spain
• B. He told me that he has visited Spain
• C. He told me that he had been to Spain✓
• D. He told me that he has been to Spain

Explanation: Option (c), "He told me that he had been to Spain," is the correct choice. It properly changes the present perfect "have been" to the past perfect "had been," which is appropriate for indirect speech since it reflects that the action occurred before the time of speaking

Q200. The smaller the value of pKb:

• A. The weaker the base
• B. The stronger the base✓
• C. The stronger the acid
• D. None of the above

Explanation: The pKb value is the negative logarithm of the base dissociation constant, Kb. It quantifies the strength of a base in a solution. A smaller pKb value reflects a larger Kb, signifying that the base dissociates more completely, thus being stronger. Therefore, Option B is correct. Option A is incorrect because it misinterprets the relationship; Option C is incorrect as it confuses the properties of acids and bases; and Option D is incorrect since Option B provides the accurate explanation.