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Etea Mdcat 2013 — Solved Past Paper with Answers
All 200 MCQs from Etea Mdcat 2013, solved with the correct answer highlighted and a full explanation for every question. This is a free MDCAT KPK / ETEA past paper — no signup, no ads. Practise it interactively in timed mode, drill more with free MDCAT MCQs, or browse all KPK / ETEA papers.
Attempt this paper interactively →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.
Why the other options are wrong
- A. We have to go toward the most appropriate option. In this option In the fridge must be followed by a comma to make it a meaningful sentence. Moreover, in the passive voice, we start a sentence with a word that is an object in active voice.
- B. The structure of this sentence is totally wrong. By preposition comes after the verb in the passive voice.
- D. Here also, the structure of the sentence is wrong.
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 has the correct punctuation, grammar and past tense hence it is correct. The rest of the options are incoherent hence incorrect.
Why the other options are wrong
- A. As active voice is in past indefinite tense , while converting it to passive voice, past indefinite tense is converted into past continuous tense helping verb with 3rd form of verb. So we will use "was" with "destroyed".
- B. Structure of this sentence is totally wrong.
- C. Object had to come in start.
Q3. 'Appraise‘ means:
- A. Tell a story at bed time
- B. Evaluate the quality of✓
- C. Do shopping in a bazaar
- D. Praise a man out of place
Explanation: Appraise means to evalute the quality or assess.
Why the other options are wrong
- A. This is not the meaning of appraise
- C. Its also not meaning of appraise, we do appraise things in bazaar
- D. It is also not a meaning of appraise
Q4. (Fix this) 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.
Why the other options are wrong
- A. a) at:This option is not correct because it does not fit the context of the sentence. "at" is used to specify a particular location or point, but it doesn't work in this sentence, which describes an urgent situation where the house is on fire.
- B. b) in:This option is not correct either because "in" is used to indicate something located inside a space or container, which doesn't fit the situation of the house being on fire.
- D. d) by:This option is not correct because "by" is used to show the agent performing an action or the means used to achieve something, which doesn't apply to the context of the sentence.
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: Cranky means to be bad-tempered or irritable, whereas spouse is ones significant other i.e theri husband or wife, therefore the answer will be B
Why the other options are wrong
- A. Cranky doesn't mean careful
- C. It does not describe cranky spouse.Option C is also not right , as it is written about only wife, whereas spouse refers to life partner
- D. It doesn't have any connection with the word cranky spouse.Option D is not right because it has no discussion about wife or husband
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 sighting of an old tutor
- C. In the love of dear sweetheart
- D. On the death of someone dear✓
Explanation: An elegy is a form of poetry in which the poet or speaker expresses grief sadness, or loss and is traditionally written in response to the death of a person or group. Therefore the answer is D.
Why the other options are wrong
- A. this poem is in a memory of dead one.
- B. this poem is on the sorrow of dead one.
- C. this poem is that love must be dead
Q8. (Fix this) My children don‘t approve….. my smoking
- A. I
- B. Of✓
- C. On
- D. At
Explanation: "of" is the correct preposition to use in this sentence to show the relationship between the verb "approve" and the subject "my smoking".
Why the other options are wrong
- A. "I" is a subject pronoun and does not fit in the sentence in a way that makes sense.
- C. "On" does not work as a preposition to convey the relationship between "approve" and "my smoking" in this sentence.
- D. "At" also does not work as a preposition to convey the relationship between "approve" and "my smoking" in this sentence.
Q9. 'Break the ice‘ Implies:
- A. Walk on ice-heet
- B. Swallow ice-cubes
- C. Chisel an ice-block
- D. To make a beginning✓
Explanation: It means to do or say something to relieve tension or get conversations going in a strained situation or when strangers meet, hence the answer will be D
Why the other options are wrong
- A. This option don't even makes sense.
- B. it is not right.
- C. it's an idiom which doesn't has direct 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.
Why the other options are wrong
- A. This sentence is grammatically correct, but the adverb "certainly" feels awkwardly placed. So, this option is not correct.
- B. This statement is grammatically correct, but again the placement of "certainly" feels awkward. So, this option is also incorrect.
- D. This sentence is not grammatically correct because the subject and verb are separated by a phrase ("the best person certainly"). So, this option is also incorrect.
Q11. 'Denounce‘ means:
- A. To reject straight away
- B. To praise in a meeting
- C. To condemn publicly✓
- D. To negoticate secretly
Explanation: Denounce means to publicly condemn against something or someone, therefore the answer is C.
Why the other options are wrong
- A. a) To reject straight away:This option suggests that 'denounce' means to reject something immediately and outright. However, this is not the correct meaning of 'denounce.' To denounce something means to publicly declare strong disapproval or condemnation of it, not merely rejecting it outright.
- B. b) To praise in a meeting:This option states that 'denounce' means to praise something in a meeting. This is not correct. The word 'denounce' has the opposite meaning; it means to criticize or condemn something openly, not to praise it.
- D. d) To negotiate secretly:This option suggests that 'denounce' means to negotiate something secretly. However, this is not accurate. The word 'denounce' does not relate to negotiation at all. Instead, it deals with expressing condemnation or disapproval publicly.
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.
Why the other options are wrong
- B. This is also a correct passive voice. However, it is slightly less common to put the prepositional phrase "for dangerous driving" at the end of the sentence.
- C. This sentence is not incorrect, but it is not the typical word order in English. The object "police" still becomes the subject, but it sounds more natural to put the prepositional phrase after the verb "was arrested".
- D. This sentence is grammatically correct, but it is very formal and not commonly used in everyday English.
Q13. Selaginella is the living member of:
- A. Psilopsida
- B. Lycopsida✓
- C. Sphenopsida
- D. Pterosida
Explanation: Selaginella belongs to the class of lycopodiopsida as it has scale-leaves bearing a ligule and has spores of 2 types. Hence, the correct answer will be B.
Why the other options are wrong
- A. In Psilopsida, plants have rootless sporophytes. The stem is differentiated into an underground rhizome and an aerial part. The aerial branches are green, lealess and bear small veinless outgrowths. Psilotum and Tmesipteris are two living examples of Psilopsida.
- C. In Sphenopsida (Horsetails), the sporophyte is differentiated into root, stem and leaves. The leaves may be expanded or scale-like and are always arranged in whorls. Plants belonging to this group are also called arthrophytes because the whole plant body is composed of a large number of joints. Equisetum is its example.
- D. Pteropsida is a subdivision of vascular plants that is no longer in use. It included all flowering plants and ferns and was divided into Filicinae, Gymnospermae, and Angiospermae.
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 use action potentials so they can contract for longer.
Why the other options are wrong
- A. a) Skeletal muscles:This option suggests that contraction can be sustained for a long period of time by skeletal muscles. Skeletal muscles are the muscles attached to our bones that are responsible for voluntary movements, such as walking and running. While skeletal muscles can sustain contractions for some time, they are not as efficient in sustaining prolonged contractions compared to other types of muscles.
- C. c) Cardiac muscles:This option suggests that contraction can be sustained for a long period of time by cardiac muscles. Cardiac muscles are the specialized muscles found in the heart responsible for pumping blood. These muscles have exceptional endurance and can contract rhythmically and continuously throughout a person's lifetime without tiring.
- D. this option is incorrect.
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.
Why the other options are wrong
- A. 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.
- B. 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.
- D. 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 have 1% DNA, as they are smaller cells.
Why the other options are wrong
- B. b) 2%:This option states that the amount of DNA in a bacterial cell is 2%. This statement is not accurate either. The amount of DNA in a bacterial cell is more than 2% of the cell's content.
- C. c) 3%:This option suggests that the amount of DNA in a bacterial cell is 3%. This statement is also not correct. The amount of DNA in a bacterial cell is higher than just 3% of the cell's content.
- D. d) 4%:This option states that the amount of DNA in a bacterial cell is 4%..However, even this option is not entirely accurate. The amount of DNA in a bacterial cell is typically higher than 4% of the cell's content.
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.
Why the other options are wrong
- A. a) Hair:This option suggests that keratinized epithelium is found in hair. Keratin is a tough, fibrous protein that forms the main structural component of hair, and hair is made up of keratinized epithelial cells. These cells become filled with keratin as they grow, providing strength and protection to the hair shaft.
- C. c) Bone:This option suggests that keratinized epithelium is found in bone. This statement is not correct. Keratinized epithelium is not a component of bone tissue. Bone tissue consists of specialized cells and a mineralized extracellular matrix that gives bone its strength and rigidity.
- D. d) Muscle:This option states that keratinized epithelium is found in muscle. This statement is not correct. Keratinized epithelium is not associated with muscle tissue. Muscle tissue is primarily composed of muscle cells (muscle fibers) that contract to generate force and movement.
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.
Why the other options are wrong
- A. a) Zygomycota: This option suggests that mushrooms belong to the phylum Zygomycota. However, this is not correct. Zygomycota is a phylum of fungi that includes various mold species but not mushrooms. Members of Zygomycota produce zygospores during their sexual reproduction.
- B. b) Ascomycota: This option states that mushrooms belong to the phylum Ascomycota. This statement is not correct either. While Ascomycota is a phylum of fungi that includes various important fungal groups such as sac fungi and morels, it does not encompass mushrooms.
- D. d) Deuteromycota: This option states that mushrooms belong to the phylum Deuteromycota. This statement is not correct. Deuteromycota, also known as Fungi Imperfecti, was once considered a formal phylum, but it is no longer recognized as a natural taxonomic group. It consists of fungi that do not fit into any other established phylum, and it is not used to classify mushrooms.
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.
Why the other options are wrong
- B. 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.
- C. This option is incorrect. 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.
- D. This option is incorrect. 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.
Why the other options are wrong
- A. The total aggregate of genes in a population at any one time is called the population’s gene pool. It consists of all alleles at all gene loci in all individuals of the population.
- C. A genetic mutation is a change to a gene's DNA sequence to produce something different. It creates a permanent change to that gene's DNA sequence.
- D. Gene flow — also called migration — is any movement of individuals, and/or the genetic material they carry, from one population to another.
Q21. N2(g) + 3H2 (g) ------> 2NH3(g), △H= 46.1 kj/mole For the reaction above which statement is true about the equilibrium constant (Keq):
- A. Keq Increases with increase in temperature✓
- B. Keq decreases with increase in temperature
- C. Keq decreases with increase in pressure
- D. Keq increases with 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.
Why the other options are wrong
- B. this option is incorrect Keq does not decrease with increase in temperature.
- C. this option is incorrect Keq does not decrease with increase in pressure .
- D. this option is incorrect Keq does not decrease with decrease in pressure .
Q22. Number of chromosomes in Tobacco is:
- A. 45
- B. 48✓
- C. 46
- D. 47
Explanation: Tobacco is an allopolyploid species (n=24 in a gamete) , hence the answer will be (2x24) that is B.
Why the other options are wrong
- A. a) 45:This option suggests that the number of chromosomes in Tobacco is 45. This statement is not correct. Tobacco typically has a different number of chromosomes.
- C. c) 46:This option suggests that the number of chromosomes in Tobacco is 46. This statement is not correct. While the number 46 is the standard diploid number of chromosomes found in humans and many other animals, it is not the number of chromosomes in Tobacco.
- D. d) 47:This option suggests that the number of chromosomes in Tobacco is 47. This statement is not correct. Tobacco typically has a different number of chromosomes.
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.
Why the other options are wrong
- A. a) Digestion:This option suggests that the appendix may play a role in digestion. This statement is not entirely accurate. While the appendix was previously thought to be a vestigial structure with no significant function in humans, recent research suggests that it may have a minor role in the digestive system. The appendix contains some lymphoid tissue, which could potentially contribute to the body's immune response related to the digestive tract. However, its primary role is not directly involved in digestion.
- B. b) Excretion:This option states that the appendix may play a role in excretion. This statement is not correct. The appendix is not involved in the excretion of waste products from the body. Excretion primarily occurs through organs like the kidneys and the urinary system, not through the appendix.
- D. d) Movement:This option states that the appendix may play a role in movement. This statement is not correct. The appendix is not directly involved in movement. It is an organ that is located near the junction of the small intestine and large intestine and does not have a primary function related to movement.
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.
Why the other options are wrong
- A. a) Kidney:This option suggests that urea formation occurs in the kidney. This statement is not correct. While the kidney plays a crucial role in the excretion of urea from the body, it is not where urea is formed. Urea is produced in a different organ.
- C. c) Spleen:This option suggests that urea formation occurs in the spleen. This statement is not correct. The spleen is not involved in urea formation. It is an organ that plays a role in filtering and removing damaged or old blood cells from circulation and is not related to urea synthesis.
- D. d) Lungs:This option states that urea formation occurs in the lungs. This statement is not correct. The lungs are not involved in the production of urea. The lungs primarily function in the exchange of gases (oxygen and carbon dioxide) during respiration.
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.
Why the other options are wrong
- A. A Golgi body, also known as a Golgi apparatus, is a cell organelle that helps process and package proteins and lipid molecules, especially proteins destined to be exported from the cell. Named after its discoverer, Camillo Golgi, the Golgi body appears as a series of stacked membranes.
- C. Peroxisomes are organelles that sequester diverse oxidative reactions and play important roles in metabolism, reactive oxygen species detoxification, and signaling. Oxidative pathways housed in peroxisomes include fatty acid β-oxidation, which contributes to embryogenesis, seedling growth, and stomatal opening.
- D. Glyoxysomes are specialized types of plant peroxisomes containing glyoxylate cycle enzymes, which participate in the conversion of lipids to sugar during the early stages of germination in oilseeds.
Q26. A student measures a current as 0.05 A. Which of the following correctly expresses this result?
- A. 50 mA✓
- B. 50 MA
- C. 500 mA
- D. 500 MA
Explanation: 0.05 A can be written as 50 mA so option A is correct.
Why the other options are wrong
- B. 0.05 A can be written as 50 mA.
- C. 0.05 A can be written as 50 mA.
- D. 0.05 A can be written as 50 mA.
Q27. Spiders belong to class:
- A. Crustacean
- B. Myriapoda
- C. Arachnida✓
- D. Hexapoda
Explanation: Spiders belong to the class of arachnida which is a class of joint legged invertebrate animals. Therefore the answer is C.
Why the other options are wrong
- A. Crustaceans are aquatic and have gills for respiration. On the dorsal side of the cephalothorax the exoskeleton is in the form of carapace. In the exoskeleton deposition of salts in addition to chitin makes it more firm. Daphnia, Cyclops, Crabs, lobsters, prawn and woodlouse belong to this class.
- B. In members of class myriapoda, the body is divided into a large number of segments each having a pair of legs. A pair of antennae and a pair of eyes are present on the head e.g. centipedes and millipedes.
- D. Hexapods are named for their most distinctive feature: a consolidated thorax with three pairs of legs (six legs). Most other arthropods have more than three pairs of legs.
Q28. Polysaccharide cellulose is the building material of:
- A. Primary cell-wall✓
- B. Secondary cell-wall
- C. Middle lamella
- D. Plasma membrane
Explanation: Cellulose contains lignin, a polysaccharide that is the building material of the primary cell wall in plants. Hence the answer is A.
Why the other options are wrong
- B. The secondary wall is formed on its inner surface and is comparatively thick and rigid. Chemically it is composed of inorganic salts, silica, waxes, cutin lignin etc.
- C. The middle lamella is first to be formed in between the primary walls of the neighboring cells.Its main composition is said to be pectin and pectic acid.
- D. Plasma membrane or cell membrane is the outermost boundary of the cell. However, in most plant cells, it is covered by a cell wall. Cell membrane is chemically composed of lipids and proteins; 60 - 80% are proteins, while 20-40% are lipids. In addition there is a small quantity of carbohydrates.
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.
Why the other options are wrong
- A. In members of class myriapoda, the body is divided into a large number of segments each having a pair of legs. A pair of antennae and a pair of eyes are present on the head e.g. centipedes and millipedes.
- B. Class Arachnida is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes spiders, scorpions, ticks, mites, camel spiders, whip spiders and vinegaroons.
- C. Hexapods are named for their most distinctive feature: a consolidated thorax with three pairs of legs (six legs). Most other arthropods have more than three pairs of legs.
Q30. Pigeon odour is released from the water bloom of:
- A. Slime mold
- B. Water mold
- C. Cyanobacteria
- D. Cyanobacteria Algae ponds✓
Explanation: Algae ponds produce a pungent odour.
Why the other options are wrong
- A. Myxomycetes or plasmodial slime molds are commonly seen on decaying forest litter and rotting wood. They play an important role as decomposers and recyclers of nutrients in the food web. Their diet consists of the bacteria which feed on decomposing plant matter.
- B. Water molds produce asexual spores, called zoospores, which use surface water (such as rain or dew on plants) for movement. They also produce sexual spores, called oospores, that are double-walled, spherical structures used to survive adverse environmental conditions.
- C. The cyanobacteria are the largest and most diverse group of photosynthetic bacteria which was previously known as ‘blue green algae’. Cyanobacteria are true prokaryotes. They vary greatly in shape and appearance. They range in diameter from about 1-10um and may be unicellular, exist as colonies of many shapes, or form filaments consisting of trichomes (chains of cells) surrounded by mucilaginous sheath. They have normal Gram-negative type cell walls. They lack flagella and often use gas vesicles to move in the water, and many filamentous species have gliding motility.
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.
Why the other options are wrong
- A. a) Stomach:This option suggests that Brunner's glands are found in the stomach. This statement is not correct. Brunner's glands are not located in the stomach.
- C. c) Ileum:This option suggests that Brunner's glands are found in the ileum. This statement is not correct. While the ileum is part of the small intestine, Brunner's glands are not present in this region.
- D. d) Colon:This option states that Brunner's glands are found in the colon. This statement is not correct. Brunner's glands are not located in the colon.
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.
Why the other options are wrong
- B. A facultative parasite is an organism that may resort to parasitic activity, but does not absolutely rely on any host for completion of its life cycle. Examples of facultative parasitism occur among many species of fungi, such as family members of the genus Armillaria.
- C. An obligate saprophyte is an organism that relies completely on dead matter.
- D. An obligate parasite is a parasitic organism that is not able to complete its life cycle without exploitation of a suitable host. They can grow within a living cell only. They must live parasitically on the host and they die when the host dies.
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.
Why the other options are wrong
- A. a) Polypeptides:This option suggests that erepsin acts upon polypeptides. This statement is partially correct. Erepsin is a type of digestive enzyme that acts on polypeptides, which are long chains of amino acids formed during protein digestion. Erepsin helps to further break down polypeptides into individual amino acids, which can then be absorbed by the small intestine and utilized by the body for various functions.
- B. b) Carbohydrates:This option states that erepsin acts upon carbohydrates. This statement is not correct. Erepsin is not involved in carbohydrate digestion. Carbohydrate digestion primarily involves enzymes such as amylase, which breaks down carbohydrates into simpler sugars.
- D. d) Fats:This option states that erepsin acts upon fats. This statement is not correct. Erepsin is not involved in fat digestion. Fat digestion primarily involves enzymes like lipase, which breaks down fats into fatty acids and glycerol.
Q34. Microsporum furfur causes:
- A. Athlete‘s foot
- B. Ring wormergot✓
- C. Dandruff
- D. None of these
Explanation: Microsporum furfur is a fungus that causes ring worms, hence the answer is B.
Why the other options are wrong
- A. Athlete's foot is caused by the same type of fungi (dermatophytes) that cause ringworm and jock itch. Damp socks and shoes and warm, humid conditions favor the organisms' growth.
- C. The major culprit of dandruff is a fungus called Malassezia. This fungus exists on most adults' scalps. It feeds on the oils on your scalp, breaking it down and leaving oleic acid in its place. Many people are sensitive to oleic acid.
- D. this option is incorrect.
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.
Why the other options are wrong
- B. b) Cartilaginous fishes:This option states that the gills are covered by operculum in cartilaginous fishes. This statement is not correct. Cartilaginous fishes, such as sharks and rays, do not have an operculum. Instead, they have separate gill slits on the sides of their body that allow water to pass through and come into direct contact with the gills for gas exchange.
- C. c) Lung fishes:This option suggests that the gills are covered by operculum in lung fishes. This statement is not correct. Lung fishes belong to a group of freshwater fishes that have both gills and a lung-like organ, allowing them to breathe air in oxygen-poor environments. They do not possess an operculum to cover their gills.
- D. d) Jawless fishes:This option states that the gills are covered by operculum in jawless fishes. This statement is not correct. Jawless fishes, such as lampreys and hagfishes, lack jaws and have simple gill openings without an operculum.
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.
Why the other options are wrong
- A. Adiantum shows a regular alternation of sporophytic and gametophytic generations. Both generations are independent. Sporophyte produces the haploid spores by meiosis. The spores germinate to form haploid prothallus or gametophyte
- B. Pinus is monoecious. Plant develops both male and female strobili on the same plant. The strobili are monosporous. There is no vegetative reproduction in Pinus.
- D. In seed plants such as mustard plant , the evolutionary trend led to a dominant sporophyte generation, and at the same time, a systematic reduction in the size of the gametophyte: from a conspicuous structure to a microscopic cluster of cells enclosed in the tissues of the sporophyte.
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).
Why the other options are wrong
- A. a) It is used in large scale production of cable insulator:This option suggests that polyvinyl chloride (PVC) is used in the large-scale production of cable insulators. This statement is correct. PVC is widely used in the manufacturing of cable insulators due to its excellent electrical insulating properties, durability, and cost-effectiveness.
- C. c) It is a homopolymer:This option suggests that polyvinyl chloride is a homopolymer. This statement is correct. As mentioned earlier, PVC is a homopolymer because it consists of repeating units of vinyl chloride monomers bonded together.
- D. d) It is used in the manufacturing of pipes:This option states that polyvinyl chloride is used in the manufacturing of pipes. This statement is correct. PVC is one of the most commonly used materials for manufacturing pipes, especially for water distribution and drainage systems. PVC pipes are known for their durability, corrosion resistance, and affordability.
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; like humans DNA is replicated at about 50 base pairs per second. Therefore the answer is C.
Why the other options are wrong
- A. In bacteria / prokaryotes, the replication fork moves at the rate of 1000 nucleotides per second. DNA polymerase can only extend in the 5' to 3' direction, which poses a slight problem at the replication fork.
- B. The replication strategy of a virus is generally dependent upon the type of nucleic acid genome which it contains. Many classes of viruses exploit cellular proteins to replicate their genomes.Bacteria multiply quickly, but not as quickly as some viruses.
- D. this option is incorrect.
Q39. The pigments of chlorophyll a,b, and carotenoids are present in:
- A. Stroma
- B. Grana
- C. Thylakoid membrane✓
- D. Crista
Explanation: Chlorophyll a, b and carotenoids are found in the thylakoid membrane, hence the answer will be C.
Why the other options are wrong
- A. Stroma is the fluid filling up the inner space of the chloroplasts which encircle the grana and the thylakoids. In addition to providing support to the pigment thylakoids, the stroma are now known to contain chloroplast DNA, starch and ribosomes along with enzymes needed for the Calvin cycle. Stroma is composed of photosynthetic proteins, starch grains, DNA, and ribosomes.
- B. Grana, the plural of granum, are piles of designs called thylakoids, which are little plates of layer on which light-subordinate photosynthesis responses happen.
- D. Cristae are folds in the inner mitochondrial membrane. Mitochondria are organelles in eukaryotic cells. The major function of cristae is to increase the surface area of the mitochondrial membrane. This allows membrane processes to produce more energy at a faster rate.
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.
Why the other options are wrong
- A. a) Teeth:This option suggests that teeth are filter feeders. This statement is not correct. Teeth are not filter feeders. They are specialized structures found in the mouth of vertebrates (animals with a backbone) that are used for biting, chewing, and grinding food. Teeth play a crucial role in the mechanical breakdown of food during the process of digestion.
- C. c) Freshwater muscle:This option suggests that freshwater mussels are filter feeders. This statement is correct. Freshwater mussels are filter-feeding bivalve mollusks. They use specialized gills to filter small organic particles, plankton, and nutrients from the water in which they live. This feeding method helps them obtain their food while also helping to maintain water quality in their environment.
- D. d) Jellyfish:This option states that jellyfish are filter feeders.Jellyfish are marine animals belonging to the phylum Cnidaria. They are known for their bell-shaped bodies and stinging tentacles. Jellyfish are filter feeders and use their tentacles to capture plankton and other small organisms from the water. They then bring the captured food particles to their mouths for ingestion.
Q41. Myoglobin is found in:
- A. Bone
- B. Connective tissue
- C. Muscles✓
- D. Cartilage
Explanation: Myoglobin is found in the heart and skeletal muscles, hence the answer will be C.
Why the other options are wrong
- A. Bones are made up of a framework of a protein called collagen, with a mineral called calcium phosphate that makes the framework hard and strong. Bones store calcium and release some into the bloodstream when it's needed by other parts of the body.
- B. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. Loose connective tissue works to hold organs in place and is made up of extracellular matrix and collagenous, elastic and reticular fibers.
- D. Cartilage is a strong, flexible connective tissue that protects your joints and bones. It acts as a shock absorber throughout your body. Cartilage at the end of your bones reduces friction and prevents them from rubbing together when you use your joints.
Q42. Thalassaemia major is also known as:
- A. Sickle cell anemia
- B. Cooley‘s anemia✓
- C. Mycocystic anemia
- D. Nutritional anemia
Explanation: Thalassaemia major is also known as cooley's anemia.
Why the other options are wrong
- A. Sickle cell anemia is an inherited disease caused by a defect in a gene. A person will be born with sickle cell disease only if two genes are inherited—one from the mother and one from the father. A person who inherits just one gene is healthy and said to be a "carrier" of the disease.
- C. Microcytic anemia is defined as the presence of small, often hypochromic, red blood cells in a peripheral blood smear. Iron deficiency is the most common cause of microcytic anemia.
- D. The term 'nutritional anemia' encompasses all pathological conditions in which the blood hemoglobin concentration drops to an abnormally low level, due to a deficiency in one or several nutrients. The main nutrients involved in the synthesis of hemoglobin are iron, folic acid, and vitamin B12-
Q43. The birds excrete:
- A. Ammonia
- B. Urea
- C. Uric acid✓
- D. Acetic acid
Explanation: Nitrogenous waste is excreted in the form of uric acid in birds.
Why the other options are wrong
- A. Ammonia is very toxic and dissolves quickly in body fluids. Thus, it must be kept in low concentration in the body. To maintain its low concentration below that of the body requires a large volume of water also to eliminate it in urine as it is produced. This is possible in a hypotonic environment. Therefore, ammonia is kept as the excretory product of the animals inhabiting hypotonic (e.g. fresh water) environments. About 500 ml water is needed to excrete 1g of ammonia nitrogen.
- B. In restricted supply of water, ammonia cannot be kept as excretory product, the other alternative is to change it into a less toxic substance such as urea. Urea requires only 50 ml of water for its 1g of nitrogen removal. Here, excretory nitrogen is metabolically converted into urea by urea cycle in the animals inhabiting an environment with restricted supply of water e.g. terrestrial mammals.
- D. Since bacteria exist in a very competitive environment where nutrients are usually in short supply. They tend to store extra nutrients when possible. These may be glycogen, sulphur, fat and phosphate. In addition, cells contain waste materials that are subsequently excreted. For example, common waste materials are alcohol, lactic acid and acetic acid.
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.
Why the other options are wrong
- B. b) Underground stems:This option states that bulliform cells are present in underground stems. This statement is not correct. Bulliform cells are not typically found in underground stems. They are primarily associated with the leaves of grasses and similar plants.
- C. c) Fruit-nuts:This option suggests that bulliform cells are present in fruit-nuts. This statement is not correct. Bulliform cells are not related to fruit-nuts. They are specific to the leaves of certain plant species, as mentioned earlier.
- D. d) Cabbage leaves:This option states that bulliform cells are present in cabbage leaves. This statement is not correct. Bulliform cells are not found in cabbage leaves. They are specific to certain types of plants, particularly grasses and monocotyledonous plants.
Q45. Bone is surrounded by a membrane called:
- A. Perichondrium
- B. Prostomium
- C. Perimycium
- D. Periosteum✓
Explanation: The tough, thin outer membrane covering the bones is called periosteum.
Why the other options are wrong
- A. b) Prostomium:This option states that bone is surrounded by a membrane called prostomium. This statement is not correct. The prostomium is not related to bone. It is a structure found in some invertebrates, particularly in annelids, and is a sensory and feeding structure located at the anterior end of the body.
- B. b) Prostomium:This option states that bone is surrounded by a membrane called prostomium. This statement is not correct. The prostomium is not related to bone. It is a structure found in some invertebrates, particularly in annelids, and is a sensory and feeding structure located at the anterior end of the body.
- C. c) Perimycium:This option suggests that bone is surrounded by a membrane called perimycium. This statement is not correct. There is no anatomical structure called perimycium related to 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.
Why the other options are wrong
- A. Auxins are indole acetic acid (IAA) or its variants. In stem, promote cell enlargement in the region behind the apex. They promote cell division in cambium. In root, auxins promote growth at very low concentrations. They promote growth of roots from cuttings and calluses
- B. Gibberellins are produced commercially from fungal cultures. They promote cell enlargement in the presence of auxins and also promote cell division in apical meristem and cambium. They promote ‘bolting’ of some rosette plants
- D. Abscisic acid inhibits stem and root growth notably during physiological stress, e.g. drought, and waterlogging. • Promotes bud and seed dormancy and it also promotes flowering in short day plants, and inhibits in long day plants (antagonistic to gibberellins). Sometimes it promotes leaf senescence.
Q47. Meissner corpuscles are the receptors for
- A. Temperature
- B. Pain
- C. Pressure
- D. Touch✓
Explanation: Mesissner corpuscles are an integral aspect of the human sensory system, required for discriminatory touch and grip control. Therefore the answer is D.
Why the other options are wrong
- A. a) Temperature:This option suggests that Meissner corpuscles are the receptors for temperature. This statement is not correct. Meissner corpuscles are not specifically associated with temperature sensation. Temperature sensation is primarily detected by specialized nerve endings known as thermoreceptors.
- B. b) Pain:This option states that Meissner corpuscles are the receptors for pain. This statement is not correct. Meissner corpuscles are not involved in pain sensation. Pain is detected by pain receptors, also known as nociceptors, which are specialized nerve endings that respond to potentially damaging stimuli.
- C. c) Pressure:This option suggests that Meissner corpuscles are the receptors for pressure. This statement is not correct. Meissner corpuscles are not related to pressure sensation. Pressure sensation is typically detected by mechanoreceptors, which are nerve endings specialized to respond to mechanical forces like pressure.
Q48. Florigen is produced by:
- A. Flowers
- B. Flower-buds
- C. Leaves✓
- D. Fruits
Explanation: Florigen is a hormone generated in leaf vasculature, transported to the shoot apical meristem and promotes flowering, hence the correct options is C.
Why the other options are wrong
- A. a) Flowers:This option suggests that florigen is produced by flowers. This statement is not correct. Florigen is not produced by flowers; rather, it is a signaling molecule produced in other parts of the plant that initiates flowering in response to various environmental and internal factors.
- B. b) Flower-buds:This option states that florigen is produced by flower-buds. This statement is not correct either. While flower-buds are involved in the process of flowering, they do not produce florigen. Florigen is produced in other tissues of the plant.
- D. d) Fruits:This option states that florigen is produced by fruits. This statement is not correct. Florigen is not produced in fruits; its production is mainly associated with leaves.
Q49. Who used puzzle boxes in experiment on animal learning?
- A. Pavlove
- B. E.L. Thorndike✓
- C. Konrad Lorenz
- D. Kohle
Explanation: Edward Thorndike studied learning in animals (usually cats). He devised a classic experiment in which he used a puzzle box to empirically test the laws of learning. Hence the answer is B.
Why the other options are wrong
- A. a) Pavlov:This option suggests that Pavlov used puzzle boxes in experiments on animal learning. This statement is not correct. Ivan Pavlov was a Russian physiologist best known for his work on classical conditioning with dogs, where he studied the salivary reflex. He did not use puzzle boxes in his experiments.
- C. c) Konrad Lorenz:This option suggests that Konrad Lorenz used puzzle boxes in experiments on animal learning. This statement is not correct. Konrad Lorenz, an Austrian ethologist, is known for his pioneering work on the imprinting behavior of birds and other animals. He did not use puzzle boxes in his studies.
- D. d) Kohle:This option states that Kohle used puzzle boxes in experiments on animal learning. There is no well-known psychologist or researcher by the name "Kohle" associated with the use of puzzle boxes in animal learning experiments. Therefore, this option is not correct.
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.
Why the other options are wrong
- B. The kangaroo is also a viviparous animal as it gives birth to its young ones and does not lay eggs.
- C. Both duckbill platypus and spiny anteater are ovoviviparous i.e They produce eggs and keep them inside the mother's body until the fetus develops completely and is ready to hatch.
- D. Both duckbill platypus and spiny anteater are ovoviviparous i.e They produce eggs and keep them inside the mother's body until the fetus develops completely and is ready to hatch.
Q51. Cristea of mitochondria are the sites of:
- A. Electron transport chain✓
- B. Photophosphorylation
- C. Krebs cycle
- D. Glycolysis
Explanation: Mitochondrial cristae are the main sites of biological energy conversion in all non-photosynthetic eukaryotes, like the electron transport chain. Therefore the answer will be A.
Why the other options are wrong
- B. In eukaryotes, photophosphorylation occurs in chloroplasts to produce ATP.
- C. In eukaryotes, the Krebs cycle reactions take place in the mitochondrial matrix, a dense solution that surrounds the mitochondria crests: in addition to water, the matrix contains all the enzymes necessary for the biochemical reactions of the cycle, coenzymes, and phosphates.
- D. The process of glycolysis occurs in the cytoplasm of the cell.
Q52. Muscles develop from:
- A. ectoderm
- B. mesoderm✓
- C. endoderm
- D. all of the above
Explanation: Muscles and bones are formed from the mesoderm, therefore the correct answer will be B.
Why the other options are wrong
- A. The systems such as integumentary and nervous system develop from ectoderm.
- C. Endoderm forms the lining of the digestive tract and glands of the digestive system, such as the liver. The digestive system is of tube type i.e. having mouth at the anterior end and the anus at the posterior end.
- D. this option is incorrect.
Q53. Bacteria maintain their survival by the formation of:
- A. Hormogonia
- B. Akinetes
- C. Endospores✓
- D. Zygospores
Explanation: Bacteria maintain their survival via the formation of endospores, hence the answer is C.
Why the other options are wrong
- A. All cells in the trichome are mostly similar in structure but at intervals are found slightly large , round, light yellowish thick walled cells called heterocysts. Trichomes mostly break near heterocyst and form hormogonia and thus help in fragmentation.
- B. Akinetes are thick walled , enlarged vegetative cells which accumulate food and become resting cells. On arrival of favorable conditions they form normal vegetative cell
- D. The spores produced by fungi and protists are known as zygospores. These spores are robust and resistant in nature. The spores are formed by the fusion of two haploid nuclei and result in gametangia.
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.
Why the other options are wrong
- A. a) 1869:This option suggests that Avery, Macleod, and McCarty repeated the Griffith experiment in the year 1869. This statement is not correct. The Griffith experiment was not conducted in 1869. It was performed much later.
- B. b) 1928:This option states that Avery, Macleod, and McCarty repeated the Griffith experiment in the year 1928. This statement is not correct. While the Griffith experiment itself was conducted in 1928 by Frederick Griffith, the work of Avery, Macleod, and McCarty was not a repetition of the Griffith experiment; rather, it was a follow-up study building on Griffith's findings.
- D. d) 1952:This option states that Avery, Macleod, and McCarty repeated the Griffith experiment in the year 1952. This statement is not correct. The experiments by Avery, Macleod, and McCarty were conducted in 1944, not 1952.
Q55. Microvilli are also called:
- A. Leaf veins
- B. Cristae✓
- C. Capillaries
- D. Leaf midribs
Explanation: Microvilli, also known as a brush border for their appearance, are mostly found in the small intestine. They are also called 'cristae'
Why the other options are wrong
- A. a) Leaf veins:This option suggests that microvilli are also called leaf veins. This statement is not correct. Microvilli are not related to leaf veins. Leaf veins are the vascular structures found in the leaves of plants that transport water, nutrients, and sugars throughout the leaf.
- C. c) Capillaries:This option suggests that microvilli are also called capillaries. This statement is not correct. Capillaries are tiny blood vessels that form networks throughout the body, allowing for the exchange of gases, nutrients, and waste products between the blood and surrounding tissues.
- D. d) Leaf midribs:This option states that microvilli are also called leaf midribs. This statement is not correct. Leaf midribs are the central veins of a leaf that provide support and transport water and nutrients between the leaf blade and the petiole.
Q56. Cell death due to tissue damage is called:
- A. Cancer
- B. Apoptosis
- C. Necrosis✓
- D. Metastasis
Explanation: Necrosis is a form of cell injury which results in the premature death of cells in living cells by autolysis. Hence the answer will be C.
Why the other options are wrong
- A. Cancer is a disease caused when cells divide uncontrollably and spread into surrounding tissues. Cancer is caused by changes to DNA. Most cancer-causing DNA changes occur in sections of DNA called genes. These changes are also called genetic changes.
- B. Apoptosis is a type of cell death in which a series of molecular steps in a cell lead to its death. This is one method the body uses to get rid of unneeded or abnormal cells.
- D. The spread of cancer cells from the place where they first formed to another part of the body is called metastasis.
Q57. The two chains of DNA occur side by side in a:
- A. Straight direction
- B. Parallel but straight
- C. Parallel but opposite
- D. Parallel, opposite and folded spirally✓
Explanation: DNA molecules have a parallel structure, the two strands of the helix run in opposite directions to one another.
Why the other options are wrong
- A. a) Straight direction:This option suggests that the two chains of DNA occur side by side in a straight direction. This statement is not correct. The structure of DNA is a double helix, and the two chains (strands) of DNA run in a helical or twisted fashion, not in a straight direction.
- B. b) Parallel but straight:This option states that the two chains of DNA occur side by side in a parallel but straight manner. This statement is not correct. As mentioned earlier, the DNA strands are not straight but form a double helix, resembling a twisted ladder.
- C. this option is not correct.
Q58. In which of the following is the phenotypic and genotypic ratio the same?
- A. Co-dominance
- B. Over dominance
- C. Epitasis
- D. Incomplete dominance✓
Explanation: In incomplete dominance, a monohybrid cross shows the results as in the figure below; Here the genotypic and phenotypic ratios are the same, therefore the correct answer will be D.
Why the other options are wrong
- A. a) Co-dominance:In co-dominance, both alleles of a gene are expressed fully in the heterozygous condition. This means that neither allele is dominant or recessive to the other. As a result, both phenotypes associated with the alleles are expressed in the heterozygous individual. For example, in humans, the ABO blood group system is an example of co-dominance. If a person has one allele for blood type A (IA) and one allele for blood type B (IB), their blood type will be AB, and both phenotypes (A and B) will be expressed.
- B. b) Over dominance (Heterozygote advantage):In over dominance, the heterozygous individual has a phenotype that is superior or better than both of the homozygous individuals. In this case, the phenotypic ratio is not the same as the genotypic ratio because the heterozygous individual displays a different phenotype from either homozygous individual. A classic example of over dominance is sickle cell anemia, where individuals who are heterozygous for the sickle cell trait (HbAS) have an advantage in regions where malaria is prevalent.
- C. c) Epistasis:In epistasis, the expression of one gene masks or modifies the expression of another gene. The phenotypic ratio is not the same as the genotypic ratio in epistasis, as the presence of one allele at one gene locus affects the expression of alleles at another gene locus, resulting in different phenotypic ratios.
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.
Why the other options are wrong
- B. Chitin is one of the most important biopolymers in nature. It is mainly produced by fungi, arthropods and nematodes. In insects, it functions as scaffold material, supporting the cuticles of the epidermis and trachea as well as the peritrophic matrices lining the gut epithelium.
- C. Lignin is an important organic polymer which is abundant in cell walls of some specific cells. It has many biological functions such as water transport, mechanical support and resistance to various stresses.
- D. Pectin is a component of the cell walls of plants that is composed of acidic sugar-containing backbones with neutral sugar-containing side chains. It functions in cell adhesion and wall hydration, and pectin crosslinking influences wall porosity and plant morphogenesis.
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.
Why the other options are wrong
- B. A probe is a single stranded nucleotide sequence that will hybridize (pair) with a certain piece of DNA. Location of the probe is possible because the probe is either radioactive or fluorescent.
- C. For preparation of a recombinant DNA, the plasmid is cut with the same enzyme which was used for isolation of the gene of interest (Fig. 23.2). The gene of interest (insulin) is then joined with the sticky ends produced after cutting the plasmid with the help of another special enzyme known as DNA ligase. This enzyme seals the foreign piece of DNA into the vector. Now the two different pieces of DNA have been joined together, which is now known as recombinant DNA or chimeric DNA
- D. Plasmids are natural extrachromosomal circular DNA molecules which carry genes for antibiotic resistance and fertility etc.
Q61. When the entire body of a bacterium is covered by flagella, such a bacterium is called:
- A. Atrichous
- B. Lopho-trichous
- C. Lampi trichous
- D. Petri-trichous✓
Explanation: Bacteria bearing flagellum all over the body are called peritrichous, atrichous are those without any flagellum. Hence the correct answer is D.
Why the other options are wrong
- A. Atrichous bacteria are lacking flagella.e.g Cocci.
- B. Lophotrichous bacteria swim through fluid by rotating their flagellar bundle extended collectively from one pole of the cell body.
- C. Amphitrichous bacteria are such bacteria which are having flagella at both ends.
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. Remalns 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.
Why the other options are wrong
- B. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q63. Nucleus was discovered by:
- A. Waldyne
- B. T.H. Margan
- C. Robert Brown✓
- D. Kohler
Explanation: In 1831, Robert Brown discovered the nucleus in the cell, hence the answer is C.
Why the other options are wrong
- A. a) Waldyne:This option suggests that the nucleus was discovered by Waldyne. This statement is not correct. There is no well-known scientist or historical figure by the name "Waldyne" credited with the discovery of the nucleus.
- B. b) T.H. Margan:This option states that the nucleus was discovered by T.H. Margan. This statement is not correct. The correct spelling of the name is T.H. Morgan. While Thomas Hunt Morgan was a prominent geneticist and biologist, he is not credited with the discovery of the cell nucleus.
- D. d) Kohler:This option states that the nucleus was discovered by Kohler. This statement is not correct. There is no specific scientist or historical figure named "Kohler" associated with the discovery of the nucleus.
Q64. Which of the following is not a nucleophile?
- A. NH3
- B. HO
- C. HC = CH
- D. Br2✓
Explanation: The electron rich part of the double bond causes a dipole to form meaning that bromine becomes electron deficient and therefore becomes the electrophile (hence electrophillic addition) hence the answer is D. Rest of the options are incorrect as they have lone pair of electrons or an electron rich double bond (in case of alkenes) which makes them nucleophiles.
Why the other options are wrong
- A. a) NH3:This option suggests that NH3 (ammonia) is not a nucleophile. This statement is not correct. NH3 is a nucleophile. A nucleophile is a chemical species that donates a pair of electrons to form a new chemical bond with another atom or molecule. NH3 has a lone pair of electrons on the nitrogen atom, which makes it capable of participating in nucleophilic reactions.
- B. b) HO:This option states that HO (hydroxide ion) is not a nucleophile. This statement is not correct. HO (hydroxide ion) is indeed a nucleophile. The hydroxide ion, OH-, has a lone pair of electrons on the oxygen atom, making it a strong nucleophile that can participate in many chemical reactions.
- C. c) HC = CH:This option suggests that HC = CH (ethylene) is not a nucleophile. This statement is not correct. Ethylene (HC = CH) is not a nucleophile. Ethylene is a hydrocarbon and does not have a lone pair of electrons to donate for nucleophilic reactions.
Q65. Stroma of chloroplasts carries the fixation of
- A. N2
- B. O2
- C. CO2✓
- D. NH3
Explanation: The stroma contains the necessary enzymes for carbon fixation.
Why the other options are wrong
- A. a) N2:This option suggests that the stroma of chloroplasts carries the fixation of N2 (nitrogen gas). This statement is not correct. While nitrogen fixation is a crucial process for converting atmospheric nitrogen (N2) into a usable form by plants, it does not occur in the stroma of chloroplasts. Nitrogen fixation is mainly performed by certain nitrogen-fixing bacteria in the soil.
- B. b) O2:This option states that the stroma of chloroplasts carries the fixation of O2 (oxygen gas). This statement is not correct. The fixation of oxygen does not take place in the stroma of chloroplasts. Oxygen is primarily involved in the process of photosynthesis as a byproduct during the light reactions.
- D. d) NH3:This option states that the stroma of chloroplasts carries the fixation of NH3 (ammonia). This statement is not correct. The fixation of ammonia does not occur in the stroma of chloroplasts. Ammonia is involved in nitrogen assimilation processes that occur in other parts of the plant, such as the roots.
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.
Why the other options are wrong
- A. this option is incorrect.
- B. b) ATC:This option states that the anticodon of AUG is ATC. This statement is not correct. ATC is not the anticodon of AUG. In the genetic code, ATC codes for the amino acid isoleucine (Ile).
- D. d) UTC:This option states that the anticodon of AUG is UTC. This statement is not correct. UTC is not the anticodon of AUG. In the genetic code, UTC is not a valid codon or anticodon.
Q67. Potatoe plastids, which store starch, are known as
- A. Paramylum
- B. Amyloplasts✓
- C. Leucoplasts
- D. Glycoplasts
Explanation: Amyloplasts are plastids that produce and store starch within internal membrane compartments, commonly found in vegetative plant tissues such as tubers (potatoes) and bulbs.
Why the other options are wrong
- A. Paramylum is a reserve carbohydrate that is found in various protozoans and algae and resembles starch.
- C. The primary function of leucoplast is the storage of materials such as starch and oils.
- D. Glycoplasts are non-existent.
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.
Why the other options are wrong
- A. The temperature in the troposphere decreases with height in response. As one climbs higher, the temperature drops from an average around 62°F (17°C) to -60°F (-51°C) at the tropopause.
- B. In this region the temperature increases with height. Heat is produced in the process of the formation of Ozone and this heat is responsible for temperature increases from an average -60°F (-51°C) at tropopause to a maximum of about 5°F (-15°C) at the top of the stratosphere.
- D. The thermosphere lies between the exosphere and the mesosphere. “Thermo” means heat, and the temperature in this layer can reach up to 4,500 degrees Fahrenheit. It is the warmest place on earth.
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.
Why the other options are wrong
- A. OPTION A: The prefix "myria"
- B. OPTION B: The prefix "Giga" stands for 10^9.
- C. 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.
Why the other options are wrong
- A. Photoperiodism is the ability of plants and animals to measure environmental day length (photoperiod), typically by monitoring night length. This process underlies a biological calendar. Photoperiod is inversely correlated to the nightly duration of melatonin secretion in animals.
- B. To monitor the seasonal progression and to time their reproductive development, plants must be able to sense and remember environmental cues such as temperature. The process by which plants use a prolonged cold period – winter – to promote flowering is known as vernalization.
- D. Phytochromes are a class of photoreceptor in plants, bacteria and fungi used to detect light. They are sensitive to light in the red and far-red region of the visible spectrum.
Q71. Which one of the following is a sex-linked inheritance?
- A. Baldness✓
- B. Albinism
- C. Eye colour
- 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.
Why the other options are wrong
- B. b) Albinism:This option states that albinism is a sex-linked inheritance. This statement is not correct. Albinism is a genetic condition caused by mutations in genes that affect the production of melanin, which leads to a lack of pigment in the skin, hair, and eyes. Albinism is not sex-linked; it is typically inherited in an autosomal recessive manner, meaning both parents must carry a copy of the mutated gene for a child to have albinism.
- C. c) Eye color:This option suggests that eye color is a sex-linked inheritance. This statement is not correct. Eye color is a polygenic trait influenced by multiple genes, and it is not directly linked to the sex chromosomes (X and Y).
- D. d) Myopia:This option states that myopia (nearsightedness) is a sex-linked inheritance. This statement is not correct. Myopia is a refractive error of the eye, and its inheritance is not linked to the sex chromosomes.
Q72. When the light from two lamps falls on a screen, no interference pattern can be obtained. Why is this so?
- 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: The conditions for interference of light are: light source should be coherent and light waves should have same wavelength hence the answer will be C.
Why the other options are wrong
- A. This may also effect the interference pattern, but it is not the main reason why the interference pattern cannot be obtained.
- B. This wouldn't necessarily prevent the formation of an interference pattern, but it may affect the visibility or contrast of the pattern.
- D. This also would not necessarily prevent the formation of an interference pattern. The color of the light would only affect the color of the fringes in the pattern.
Q73. The valve between left ventricle 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.
Why the other options are wrong
- B. The bicuspid valve is situated between the left atrium and the left ventricle in the heart. It has two flaps (cusps) that open to allow blood flow from the left atrium to the left ventricle during diastole and close to prevent backflow during systole.
- C. c) Tricuspid valve:This option suggests that the valve between the left ventricle is called the tricuspid valve. This statement is not correct. The tricuspid valve is located between the right atrium and the right ventricle, not on the left side of the heart.
- D. d) Pulmonary valve:This option states that the valve between the left ventricle is called the pulmonary valve. This statement is not correct. The pulmonary valve is situated at the base of the pulmonary artery and separates the right ventricle from the pulmonary artery, not the left ventricle.
Q74. Which of the following misnamed?
- A. Aniline
- B. Methyl naphthalene
- C. Carboxyl benzene✓
- D. Benzene sulphonic acid
Explanation: When a carboxyl group is added to a Benzene ring, it is called Benzoic acid.Thus Option C is the right answer.
Why the other options are wrong
- A. a) Aniline:This option suggests that "Aniline" might be misnamed. This statement is not correct. Aniline is the correct name for the chemical compound with the molecular formula C6H5NH2. I
- B. this option is incorrect.
- D. this option is incorrect.
Q75. 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: pkb is a negative base logarithm of the base dissociation constant Kb of a solution, it is used to determine the strength of a base/alkaline solution,the smaller the value of pKb the stronger the base, therefore the answer is B.
Why the other options are wrong
- A. This option is incorrect.
- C. c) The stronger the acid:This option suggests that the smaller the value of pKb, the stronger the acid. This statement is not correct. pKb is related to bases, not acids. The strength of an acid is determined by its acid dissociation constant (Ka) and its pKa value (negative logarithm of Ka). A smaller pKa value corresponds to a stronger acid.
- D. d) None of the above:This option states that none of the given options is correct. This statement is not correct. As explained above, option (a) and option (b) are both correct. The correct answer is either option (a) or option (b), depending on how the question is framed.
Q76. Why is the boiling point of n-Pentane about 28‘C higher than that of its 2,2-Dimethylpropane isomer?
- A. The area of contact between 2,2-Dimethylpropane is small which results in weak forces of attraction.✓
- B. 2,2-dimehlprpane molecules repel each other
- C. N-pentane molecules cannot come into closer contact with each other
- D. Shapes of molecules have not effect on boiling point
Explanation: The more branched an isomer is, the smaller the area of contact and thus weaker intermolecular forces of attractions.Therefore the answer is A.
Why the other options are wrong
- B. b) 2,2-dimethylpropane molecules repel each other:This option suggests that the boiling point difference is due to repulsion between 2,2-Dimethylpropane molecules. This statement is incorrect.
- C. c) N-pentane molecules cannot come into closer contact with each other:This option suggests that the boiling point difference is because n-Pentane molecules cannot come into closer contact with each other. This statement is not correct. In n-Pentane, the linear chain allows the molecules to pack closely together, enabling stronger intermolecular forces compared to 2,2-Dimethylpropane. The ability of n-Pentane molecules to come into closer contact contributes to its higher boiling point.
- D. d) Shapes of molecules have no effect on boiling point:This option states that the shapes of molecules have no effect on the boiling point difference. This statement is not correct. The shape and structure of molecules significantly influence the strength of intermolecular forces and, therefore, the boiling points of substances. In the case of 2,2-Dimethylpropane and n-Pentane, the different shapes due to branching significantly affect their boiling points.
Q77. 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.
Why the other options are wrong
- B. b) (CH3)2CHOH:This option states that (CH3)2CHOH will undergo dehydrogenation. The chemical formula (CH3)2CHOH represents isopropanol, also known as 2-propanol. Isopropanol is a secondary alcohol, and it can undergo dehydrogenation under suitable conditions, resulting in the formation of acetone (COCH3). The α-hydrogen on the carbon adjacent to the hydroxyl group (OH) in isopropanol can be removed during dehydrogenation.
- C. c) (CH3)3COH:This option suggests that (CH3)3COH will not undergo dehydrogenation. The chemical formula (CH3)3COH represents tert-butanol, also known as 2-methyl-2-propanol. Tert-butanol is a tertiary alcohol, and tertiary alcohols do not undergo dehydrogenation because they lack α-hydrogens.
- D. d) CH3CH2OH:This option states that CH3CH2OH will undergo dehydrogenation. The chemical formula CH3CH2OH represents ethanol. Ethanol is a primary alcohol, and it can undergo dehydrogenation under suitable conditions, forming acetaldehyde (CH3CHO) as an intermediate.
Q78. 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.
Why the other options are wrong
- A. Glass is not a polymer substance. Glass is an amorphous solid that is primarily composed of silica (silicon dioxide). It is formed by cooling molten silicates rapidly, resulting in a non-crystalline, vitreous material. While glass is not a polymer, it is an important material used in various applications due to its transparency, hardness, and thermal properties.
- B. Iron is not a polymer substance. Iron is a chemical element with the symbol Fe and is a metal. It is not composed of repeating monomers like a polymer; rather, it consists of metallic bonds between iron atoms in a crystalline structure. Iron and its alloys are widely used in construction, machinery, and many other applications due to their strength and ductility.
- D. Copper is not a polymer substance. Copper is a chemical element with the symbol Cu and is a metal. Like iron, it consists of metallic bonds between copper atoms in a crystalline structure. Copper is an excellent conductor of electricity and is used in electrical wiring, plumbing, and many other applications.
Q79. 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: Enthalpy of combustion of Methane is -890kJ/mol1kJ = 0.239 kcal So 890kJ = 212.715 kcal
Why the other options are wrong
- B. This option is incorrect.
- C. This option is incorrect.
- D. This option is incorrect.
Q80. 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.
Why the other options are wrong
- A. a) Greater than 6:This option suggests that rainwater becomes acidic when the pH-value of rainwater becomes greater than 6. This statement is not correct. A pH value greater than 6 indicates that the rainwater is still slightly acidic but not to the extent of being a concern for acidity.
- B. b) Greater than 6.5:This option states that rainwater becomes acidic when the pH-value of rainwater becomes greater than 6.5. This statement is not correct. A pH value greater than 6.5 is in the neutral to slightly alkaline range, and it does not indicate acidic rainwater.
- C. c) Less than 5.6:This option suggests that rainwater becomes acidic when the pH-value of rainwater becomes less than 5.6. This statement is partially correct. Rainwater is considered acidic when its pH falls below 5.6. This can happen due to the dissolution of atmospheric pollutants such as sulfur dioxide (SO2) and nitrogen oxides (NOx), which combine with water vapor in the atmosphere to form sulfuric acid (H2SO4) and nitric acid (HNO3). These acidic compounds lower the pH of rainwater, making it acidic.
Q81. 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.
Why the other options are wrong
- A. a) 6.0 to 7.0:This option suggests that the pH of drinking water should range between 6.0 and 7.0. This statement is not entirely correct. While a pH range of 6.0 to 7.0 is considered slightly acidic to neutral, it is not the ideal pH range for drinking water. Most drinking water sources aim for a pH close to neutral (pH 7.0) to ensure it is neither too acidic nor too alkaline.
- C. c) 4.5 to 6.0:This option suggests that the pH of drinking water should range between 4.5 and 6.0. This statement is not correct. A pH range of 4.5 to 6.0 is considered acidic and is not suitable for drinking water. Water with such a low pH can be corrosive and may cause health issues if consumed.
- D. d) 8.5 to 9.0:This option states that the pH of drinking water should range between 8.5 and 9.0. This statement is not correct. A pH range of 8.5 to 9.0 is considered highly alkaline and is not suitable for drinking water. Water with such a high pH can have an unpleasant taste and may cause gastrointestinal discomfort.
Q82. 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: One gram of hydrogen contains one mole of hydrogen as its atomic weight is 1, one mole is 6.02 x 1023 atoms. Since hydrogen is diatomic the amount of molecules would be 3.01 x 1023, therefore the answer would be 3.01 x 1023, which will then be multiplied by 0.20.
Why the other options are wrong
- B. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q83. 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.
Why the other options are wrong
- B. Protons are not typically produced in a nuclear fission reaction.
- C. Electrons are not typically produced in a nuclear fission reaction.
- D. Alpha particles, which are composed of two protons and two neutrons, can be produced in certain types of nuclear reactions, but they are not typically produced in a nuclear fission reaction.
Q84. 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.
Why the other options are wrong
- A. a) Three polypeptide chains:This option suggests that a single molecule of hemoglobin is composed of three polypeptide chains. This statement is not correct. Hemoglobin is a complex protein present in red blood cells, and a single molecule of hemoglobin is actually composed of multiple polypeptide chains.
- C. c) Five polypeptide chains:This option suggests that a single molecule of hemoglobin is composed of five polypeptide chains. This statement is not correct. As explained earlier, hemoglobin is composed of four polypeptide chains, not five.
- D. d) Six polypeptide chains:This option states that a single molecule of hemoglobin is composed of six polypeptide chains. This statement is not correct. The correct number of polypeptide chains in hemoglobin is four, not six.
Q85. 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.
Why the other options are wrong
- A. a) –R:The functional group –R represents an alkyl group, which is a hydrocarbon chain. Alkyl groups are generally weakly deactivating and not ortho, para directing in electrophilic aromatic substitution reactions. Alkyl groups have a slightly electron-donating effect due to the release of electron density through hyperconjugation. However, their effect is not strong enough to significantly activate the benzene ring toward electrophilic substitution, and they do not direct incoming substituents to the ortho and para positions.
- C. c) –NH2:The functional group –NH2 represents an amino group, which is weakly activating and ortho, para directing in electrophilic aromatic substitution reactions. The amino group has a lone pair of electrons that can donate electron density to the benzene ring through resonance, making the ring more reactive toward electrophiles. Moreover, the amino group directs incoming substituents to the ortho and para positions.
- D. d) –NR2:The functional group –NR2 represents a secondary amine group, where R can be an alkyl or aryl group. Secondary amine groups are weakly activating and ortho, para directing in electrophilic aromatic substitution reactions. Similar to the –NH2 group, the lone pair of electrons on the nitrogen atom can donate electron density to the benzene ring through resonance, making it more reactive toward electrophiles. Also, the –NR2 group directs incoming substituents to the ortho and para positions.
Q86. 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.
Why the other options are wrong
- B. b) Copper and glass:In this option, copper is normally crystalline, as explained in the previous option. However, glass is not a crystalline substance. Glass is an amorphous solid, meaning it lacks long-range order in its atomic arrangement. Instead of having a regular crystal lattice, the atoms in glass are arranged in a disordered manner, leading to its non-crystalline or amorphous nature.
- C. c) Copper and rubber:In this option, copper is normally crystalline, as explained in the first option. However, rubber is not a crystalline substance. Rubber is a polymer, and its molecular structure does not have the long-range order needed for a crystalline lattice. Instead, rubber is typically amorphous in its solid state.
- D. d) Diamond and glass:In this option, diamond is normally crystalline, as explained in the first option. However, glass, as mentioned earlier, is not crystalline but amorphous.
Q87. Which one of the following is strongest acid?
- A. CH3COOH
- B. CH3 CH2 COOH
- C. C6H5CG2COOH
- D. FCH2COOH✓
Explanation: D is the correct optionas it contains a halogen which have strong electron withdrawing effects.
Why the other options are wrong
- A. a) CH3COOH (Acetic acid):This is acetic acid, also known as ethanoic acid. It is a weak acid, and its acidity is derived from the dissociation of the hydrogen ion (H+) from the carboxyl group (–COOH). It partially dissociates in water to form H3O+ and CH3COO- ions. Acetic acid is commonly found in vinegar.
- B. b) CH3CH2COOH (Propanoic acid):This is propanoic acid. It is also a weak acid, similar to acetic acid. Propanoic acid is derived from the dissociation of the hydrogen ion (H+) from the carboxyl group (–COOH). It partially dissociates in water to form H3O+ and CH3CH2COO- ions.
- C. c) C6H5CG2COOH (Benzoic acid):This is benzoic acid, which contains a phenyl group (C6H5) attached to the carboxyl group (–COOH). Benzoic acid is a weak acid, but it is slightly stronger than acetic and propanoic acids due to the electron-withdrawing effect of the phenyl group, which stabilizes the resulting carboxylate ion after dissociation.
Q88. 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.
Why the other options are wrong
- A. a) Benedicts reagent:Benedict's reagent is used to test for the presence of reducing sugars, not to distinguish between primary, secondary, and tertiary alcohols. Reducing sugars are a type of sugar that can donate electrons and reduce certain metal ions present in the Benedict's reagent. The presence of reducing sugars is indicated by a color change from blue to green, yellow, orange, or red, depending on the amount of sugar present.
- B. b) Tollen's reagent:Tollen's reagent, also known as silver mirror test, is used to distinguish between aldehydes and ketones. It involves the oxidation of aldehydes to carboxylic acids while reducing Tollen's reagent to form a silver mirror on the inside of the test tube. This test is not used to distinguish among primary, secondary, and tertiary alcohols.
- D. d) None of the above:The correct answer is not "None of the above" because the Lucas test (option c) is the specific test used to distinguish among primary, secondary, and tertiary alcohols.
Q89. 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.
Why the other options are wrong
- A. a) CH3:This option represents a methyl group, which consists of a carbon atom bonded to three hydrogen atoms. Methyl groups themselves do not participate in hydrogen bonding. Hydrogen bonding occurs between a hydrogen atom covalently bonded to an electronegative atom (e.g., oxygen, nitrogen, or fluorine) and another electronegative atom in a separate molecule.
- B. b) CH3OCH3:This compound is known as dimethyl ether. It consists of two methyl groups (CH3) linked by an oxygen atom (O). Dimethyl ether does not have hydrogen bonding. Although it contains oxygen, which is electronegative, the hydrogen atoms in the methyl groups are not bonded directly to the oxygen atom.
- D. d) C6H5OCH3:This compound is known as anisole. It consists of a phenyl group (C6H5) attached to an oxygen atom (O) with a methyl group (CH3) bonded to the oxygen. Anisole can participate in hydrogen bonding through the oxygen atom, which is bonded to a hydrogen atom.
Q90. 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.
Why the other options are wrong
- A. a) HC = CH:This structure represents ethyne, also known as acetylene. It consists of two carbon atoms triple-bonded to each other. The carbon atoms in ethyne are sp hybridized, but there is no overlap with an sp2 hybrid orbital in this molecule. Therefore, option a) is not the correct answer.
- C. c) H2C = C= CH2:This structure represents allene, also known as propadiene. It consists of three carbon atoms with the two terminal carbon atoms double-bonded to the central carbon. The terminal carbon atoms in allene are sp hybridized, and there is an overlap of sp hybrid orbitals with sp2 hybrid orbitals from the central carbon to form the double bonds.
- D. d) CH2 = CHCH3:This structure represents 2-methylpropene. It consists of three carbon atoms with a double bond between the first and second carbon atoms. The first carbon atom is sp2 hybridized, and the second carbon atom is sp3 hybridized, but there is no overlap of an sp2 hybrid orbital with an sp hybrid orbital in this molecule. Therefore, option d) is not the correct answer.
Q91. 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°.
Why the other options are wrong
- B. b) 120 degrees:This bond angle is characteristic of trigonal planar geometry, which is found in molecules with sp2 hybridization. However, ethane does not have a bond angle of 120 degrees. Trigonal planar geometry is not applicable to ethane's structure.
- C. c) 90 degrees:This bond angle is characteristic of molecules with sp hybridization. However, ethane does not have a bond angle of 90 degrees. Ethane consists of sigma (σ) bonds between the carbon atoms and hydrogen atoms, but its geometry is not linear.
- D. this option is incorrect.
Q92. 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
Why the other options are wrong
- A. a) CH3CI (methyl chloride):This is not the correct product. The reaction between PCl5 and acetic acid would not produce methyl chloride (CH3CI).
- C. c) CH3COCI2:This product is not formed in the reaction between PCl5 and acetic acid.
- D. d) CH3CH2COCI:This product is not formed in the reaction between PCl5 and acetic acid.
Q93. 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.
Why the other options are wrong
- A. a) Chain isomerism:Chain isomerism occurs when isomers differ in the arrangement of carbon atoms in the carbon chain. In the given compound FCH = CHF, there are only two carbon atoms, and their arrangement is the same in both isomers (i.e., connected by a double bond). Therefore, chain isomerism is not exhibited.
- B. b) Structural isomerism:Structural isomerism occurs when isomers have different structural arrangements of atoms, but they have the same molecular formula. In the given compound FCH = CHF, there is only one structural arrangement for the given molecular formula, so structural isomerism is not exhibited.
- D. d) Position isomerism:Position isomerism occurs when isomers have the same molecular formula but differ in the position of functional groups or substituents on the carbon chain. In the given compound FCH = CHF, there is no variation in the position of functional groups or substituents. Therefore, position isomerism is not exhibited.
Q94. 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.
Why the other options are wrong
- A. a) Alkene:The reaction between a monohydric alcohol and sodium metal does not directly lead to the formation of an alkene (a compound with a carbon-carbon double bond). The given reaction produces sodium alkoxide and hydrogen gas.
- C. c) Alkane:The reaction between a monohydric alcohol and sodium metal does not lead to the formation of an alkane (a compound with only single carbon-carbon bonds). Instead, the product is sodium alkoxide.
- D. d) Ether:The reaction between a monohydric alcohol and sodium metal does not directly produce an ether (a compound with an oxygen atom bonded to two alkyl or aryl groups). The correct product is sodium alkoxide.
Q95. 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.
Why the other options are wrong
- B. b) Renewable sources:Renewable sources refer to energy sources that are naturally replenished and can be used indefinitely. Examples of renewable sources include solar energy, wind energy, hydroelectric power, and geothermal energy. Unlike fossil fuels, these sources are not derived from ancient organic matter and can be harnessed without depleting their resources.
- C. c) Infinite sources:"Infinite sources" is not a standard term used in the context of energy or natural resources. The term "infinite" implies that the sources are endless and can never be exhausted, which is not applicable to any finite resource, including coal, natural gas, or petroleum.
- D. d) None of the above:As explained above, the correct classification for coal, natural gas, and petroleum is "fossil fuels." Therefore, option d) "None of the above" is not the correct answer.
Q96. In a vibrating cord the point where the particles are stationary is called:
- A. Node✓
- B. Anti-node
- C. Crest
- D. Trough
Explanation: Nodes are points of zero amplitude, therefore the answer will be A.
Why the other options are wrong
- B. b) Anti-node:An anti-node is a point in a vibrating medium where the amplitude of vibration is maximum. At an anti-node, the particles of the medium undergo maximum displacement from their equilibrium position. In other words, the oscillations at an anti-node are the most pronounced, and the amplitude is at its highest.
- C. c) Crest:The term "crest" is typically used in the context of transverse waves, such as water waves. A crest is the highest point of a wave, where the amplitude is maximum. In the case of vibrating cords, which involve longitudinal waves, the term "crest" is not commonly used to describe the stationary points.
- D. d) Trough:Similar to "crest," the term "trough" is commonly used in the context of transverse waves. A trough is the lowest point of a wave, where the amplitude is minimum. In vibrating cords, the term "trough" is not used to describe the stationary points.
Q97. 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.
Why the other options are wrong
- A. a) Chlorobenzene:Chlorobenzene is not the product formed in this reaction. Chlorobenzene is produced when benzene reacts with chlorine in the presence of a Lewis acid, but it is not the product of the Friedel-Crafts acylation reaction.
- C. c) Benzoic acid:Benzoic acid is not the product formed in this reaction. Benzoic acid is produced when benzene reacts with carbon dioxide (CO2) in the presence of a Lewis acid, but it is not the product of the Friedel-Crafts acylation reaction with acetyl chloride.
- D. d) Benzophenone:Benzophenone is not the product formed in this reaction. Benzophenone is produced through a different reaction called the Friedel-Crafts benzoylation, where benzene reacts with benzoyl chloride (C6H5COCl) in the presence of a Lewis acid.
Q98. 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: Bromine is eliminated and the product obtained is 2-Methyl propane hence option A is correct.
Why the other options are wrong
- B. b) 2-Methyl propene:This is not the correct product.
- C. c) 2-Methyl-1 propanol:This is not the correct product. The unimolecular elimination reaction of 2-Bromo-2-methyl propane does not result in the formation of 2-methyl-1 propanol.
- D. d) 2-pentanol:This is not the correct product. The unimolecular elimination reaction of 2-Bromo-2-methyl propane does not result in the formation of 2-pentanol.
Q99. When lead, 81Pb214, emits a ß- particle, the resultant nucleus will be:
- A. 83Bi214
- B. 84Po214
- C. 82Pb214✓
- D. 41TI214
Explanation: In Beta- particle emission the mass number remains constant while the atomic number +1.
Why the other options are wrong
- A. In this option, atomic number increases by +2. So, this option is incorrect.
- B. This option is also incorrect because atomic number increases by +3.
- D. This option is incorrect because atomic number decreases by 40.
Q100. Vinyl acetate monomer is prepared by the reaction of acetaldehyde and acetic-anhydride. The catalyst employed is:
- A. FeCI3✓
- B. AL2O3
- C. V2O5
- D. Cr2O3
Explanation: The catalyst used in this reaction is FeCl3. This has to be memorised.
Why the other options are wrong
- B. b) Al2O3 (Alumina):Al2O3 is not the correct catalyst for the preparation of vinyl acetate monomer. Alumina is a commonly used catalyst in various chemical processes, but it is not used in the Wacker process for VAM production.
- C. c) V2O5 (Vanadium pentoxide):This is not the correct catalyst for the preparation of vinyl acetate monomer. While vanadium pentoxide (V2O5) can be used as a catalyst in certain reactions, it is not the catalyst employed in the Wacker process.
- D. d) Cr2O3 (Chromium(III) oxide):This is not the correct catalyst for the preparation of vinyl acetate monomer. While chromium(III) oxide (Cr2O3) can be used as a catalyst in various reactions, it is not the catalyst used in the Wacker process for VAM production.
Q101. 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.
Why the other options are wrong
- A. a) Burning of waste material in pits:This option refers to open burning of waste material in pits, which is not an appropriate method of thermal processing for industrial waste. Open burning can lead to air pollution and the release of harmful gases and particulate matter, which can have negative environmental and health impacts.
- C. c) Energy recovery from organic matter prior to its final disposal:This option also describes a valid objective of thermal processing. Many industrial waste materials contain organic matter that can be converted into energy through processes like anaerobic digestion or incineration. The aim is to recover energy from the waste before its final disposal, reducing the environmental impact and maximizing resource utilization.
- D. d) Size reduction and compaction by thermal process:While thermal processing can lead to size reduction and compaction of certain waste materials, this is not the primary objective of thermal treatment for industrial waste. Size reduction and compaction are often achieved through mechanical methods, such as shredding or compacting machines, rather than solely relying on thermal processes.
Q102. Which one is not a nitrogenous fertilizer?
- A. Ammonium nitrate
- B. Triple phosphate✓
- C. Urea
- D. Nitro phosphate
Explanation: Triple phosphate is a phosphate fertilizer.
Why the other options are wrong
- A. a) Ammonium nitrate:Ammonium nitrate is a nitrogenous fertilizer. It is a compound that contains both ammonium ions (NH4+) and nitrate ions (NO3-), making it a source of readily available nitrogen for plants. It is commonly used in agriculture as a high-nitrogen fertilizer.
- C. c) Urea:Urea is a nitrogenous fertilizer. It is a white crystalline compound that contains a high percentage of nitrogen. Urea is widely used as a nitrogen fertilizer in agriculture due to its high nitrogen content and ease of handling.
- D. d) Nitro phosphate:Nitro phosphate is not a nitrogenous fertilizer. It is a compound that contains both nitrogen and phosphorus, but it is not primarily used as a fertilizer. Instead, it is used as an ingredient in certain explosives.
Q103. In chlorophyII-b, the porphyrine ring is attached to the:
- A. Methyl group
- B. Carboxyl group
- C. Aldehyde group✓
- D. Hydroxyl group
Explanation: c) Aldehyde group: The porphyrin ring in chlorophyll-b is attached to an aldehyde group. The aldehyde group is a functional group containing a carbonyl group (C=O) at the end of a carbon chain.
Why the other options are wrong
- A. a) Methyl group:The porphyrin ring in chlorophyll-b is not attached to a methyl group. Methyl groups are simple carbon groups consisting of three hydrogen atoms bonded to a carbon atom.
- B. The two chlorophylls i.e (A and B) differ only at position 3. Chlorophyll a contains a methyl group at this position, whereas chlorophyll b contains an aldehyde group.
- D. this option is incorrect.
Q104. Which of the following titrants would most likely be used as ths‘ own indicator in acid medium?
- A. K2Cr2O3
- B. Iodine
- C. KMnO4✓
- D. H2O2
Explanation: KMnO4 acts as an oxidising agent in acidic mediums only.
Why the other options are wrong
- A. a) K2Cr2O7 (Potassium dichromate):K2Cr2O7 is not likely to be used as its own indicator in acid medium. It is a powerful oxidizing agent and is typically used as a titrant in redox titrations rather than as an indicator.
- B. b) Iodine (I2):Iodine is not likely to be used as its own indicator in acid medium. Iodine itself does not have a distinct color change in an acid-base titration, so it is not a suitable indicator for such titrations.
- D. d) H2O2 (Hydrogen peroxide):H2O2 is not likely to be used as its own indicator in acid medium. Hydrogen peroxide itself does not have a distinct color change in an acid-base titration and is not commonly used as an indicator.
Q105. The atomic number of scandium is 21. What is its ground state electronic configuration?
- A. 1s22N22p63N23p63d3
- B. 1s22s22p63s23p63d14s2✓
- C. 1s22N22p63N23p63d34s2
- D. 1s22N22p63N23p63d34p1
Explanation: The ground state configuration is the most stable arrangement with the lowest energy.The filling of electrons is according to the Aufbau Principle which states that the lowest energy orbitals are filled first.So the ground state electronic configuration of scandium is 1s2 2s2 2p6 3s2 3p6 4s2 3d1
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q106. The centre of porphyrin ring of haemoglobin is occupied by:
- A. Magnesium
- B. Sodium
- C. Iron✓
- D. Potassium
Explanation: The haem group is a metal complex with iron as the central metal atom.
Why the other options are wrong
- A. a) Magnesium (Mg):The center of the porphyrin ring in hemoglobin is not occupied by magnesium. Although magnesium is present in chlorophyll (the green pigment in plants) and is a crucial element for photosynthesis, it is not the element present in hemoglobin.
- B. b) Sodium (Na):The center of the porphyrin ring in hemoglobin is not occupied by sodium. Sodium is an essential electrolyte in the body, but it is not part of the porphyrin ring in hemoglobin.
- D. d) Potassium (K):The center of the porphyrin ring in hemoglobin is not occupied by potassium. Potassium is an essential electrolyte in the body, but it is not part of the porphyrin ring in hemoglobin.
Q107. 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
Why the other options are wrong
- A. 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
- B. 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
- D. 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
Q108. Premature death of plants is caused by the deficiency of:
- A. Magnesium✓
- B. Iron
- C. Phosphorus
- D. Potassium
Explanation: Chlorosis is typically caused when leaves do not have enough nutrients to synthesise all the chlorophyll they need. It can be brought about by a combination of factors including: a specific mineral deficiency in the soil of Mg2+
Why the other options are wrong
- B. b) Iron (Fe):Iron deficiency can lead to yellowing of the young leaves, a condition known as chlorosis. While severe iron deficiency can weaken plants and affect their growth, it is not primarily associated with premature death.
- C. c) Phosphorus (P):Phosphorus deficiency can result in stunted growth, reduced flowering, and poor root development. It is crucial for energy transfer in plants and plays a vital role in various metabolic processes. While severe phosphorus deficiency can lead to poor plant health, it is not directly linked to premature death.
- D. this option is incorrect.
Q109. Which electronic sub-shell do the lanthanides have incompletely filled?
- A. 3f
- B. 4f✓
- C. 5f
- D. 6f
Explanation: Their 4f subshell is incompletely filled, lanthanides start from lanthanum atomic no. 57 to lutecium atomic no. 71 .
Why the other options are wrong
- A. a) 3f:The 3f sub-shell is not relevant to the lanthanides. The f-block elements, including the lanthanides, have electrons filling the 4f sub-shell.
- C. c) 5f:The 5f sub-shell is not associated with the lanthanides. Elements with electrons filling the 5f sub-shell belong to the actinide series, which is another group of f-block elements.
- D. d) 6f:The 6f sub-shell is not relevant to the lanthanides. Elements with electrons filling the 6f sub-shell belong to the superactinide series, which is a hypothetical extension of the periodic table beyond the actinides.
Q110. 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: The formula of resistance is equal to: Resistance = resistivity × length/areaDoubling the length, doubles the resistance while reducing the area to half, quadruples the resistance so in total the new resistance is 2 × 4 = 8R.
Why the other options are wrong
- A. this option is incorrect.
- B. this option is incorrect.
- D. this option is incorrect.
Q111. 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.
Why the other options are wrong
- A. a) 4:The magnetic quantum number (m) can take four different values: -4, -3, -2, -1, 0, +1, +2, +3, and +4. However, this option is not correct because there are nine different values that m can assume, not four.
- B. b) 5:The magnetic quantum number (m) can take five different values: -4, -3, -2, -1, 0, +1, +2, +3, and +4. This option is not correct because there are nine different values that m can assume, not five.
- C. c) 6:The magnetic quantum number (m) can take six different values: -4, -3, -2, -1, 0, +1, +2, +3, and +4. This option is not correct because there are nine different values that m can assume, not six.
Q112. 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.
Why the other options are wrong
- B. b) HCIO2 (Chlorous acid):Chlorous acid (HCIO2) is a different acid with the chemical formula HClO2. It is an intermediate compound in the redox reactions involving chlorine and chlorine-containing compounds.
- C. c) HCIO3 (Chloric acid):Chloric acid (HCIO3) is another acid with the chemical formula HClO3. It is a strong acid and is used as an oxidizing agent in certain chemical reactions.
- D. d) HCIO4 (Perchloric acid):Perchloric acid (HCIO4) is yet another acid with the chemical formula HClO4. It is a strong acid and is widely used in various chemical processes.
Q113. 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: Using the formula M1V1=M2V2 Or M2= M1V1/V2 = 0.5*0.02/1 = 0.01 M
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q114. Which one of the following oxides exhibit amphoteric properties?
- A. K2O
- B. MgO
- C. ZnO✓
- D. CaO
Explanation: Zinc oxide is amphoteric because it reacts with both acids and bases to form salts. Hence the answer is C.
Why the other options are wrong
- A. a) K2O (Potassium oxide):Potassium oxide is a basic oxide. It readily reacts with water to form a strong base, potassium hydroxide (KOH), but it does not exhibit amphoteric properties.
- B. b) MgO (Magnesium oxide):Magnesium oxide is a basic oxide. It reacts with water to form magnesium hydroxide (Mg(OH)2) and does not exhibit amphoteric properties.
- D. d) CaO (Calcium oxide):Calcium oxide is a basic oxide. It reacts with water to form calcium hydroxide (Ca(OH)2) and does not exhibit amphoteric properties.
Q115. Which one of the following salts will produce an alkaline solution when dissolved in water?
- A. NH4CI
- B. NaNO3
- C. Na2CO3✓
- D. Na2SO4
Explanation: Na2CO3 will form an alkaline solution because its formed by the reaction of a strong base NaOH and a weak acid H2CO3. Therefore the answer will be C.
Why the other options are wrong
- A. a) NH4Cl (Ammonium chloride):Ammonium chloride is an acidic salt. When dissolved in water, it forms an acidic solution due to the presence of ammonium ions (NH4+) that can react with water to produce hydronium ions (H3O+), making the solution acidic.
- B. b) NaNO3 (Sodium nitrate):Sodium nitrate is a neutral salt. When dissolved in water, it forms a neutral solution since neither sodium ions (Na+) nor nitrate ions (NO3-) significantly affect the pH of the solution.
- D. d) Na2SO4 (Sodium sulfate):Sodium sulfate is a neutral salt. When dissolved in water, it forms a neutral solution since neither sodium ions (Na+) nor sulfate ions (SO4^2-) significantly affect the pH of the solution.
Q116. 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.
Why the other options are wrong
- A. a) -2:An ion with a valency of -2 would gain two electrons. However, atom A already has one electron in its outermost shell (4s^1). To achieve a stable electron configuration, it is more likely to lose one electron rather than gain two electrons.
- B. b) -1:An ion with a valency of -1 would gain one electron. As mentioned earlier, atom A is more likely to lose an electron from its outermost shell (4s^1) to achieve a stable electron configuration.
- C. c) +2:An ion with a valency of +2 would lose two electrons. As stated earlier, atom A is more likely to lose only one electron from its outermost shell (4s^1) to attain a stable electron configuration.
Q117. 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, considered in its role as a component of an atomic nucleus.
Why the other options are wrong
- A. The atomic nucleus is the small, dense region consisting of protons and neutrons at the centre of an atom. So, it is an incorrect option.
- B. An atom is radioactive if the nucleus has an excess of internal energy. Instability of an atom's nucleus may result from an excess of either neutrons or protons. So, it is an incorrect option.
- D. It is an incorrect option according to the definition of nucleon.
Q118. 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.
Why the other options are wrong
- A. a) Greenish, tasteless, and light:This option is not correct. Ozone gas is not greenish in color, and it does not have any taste. It is a pale blue gas.
- B. b) Greenish-blue, bitter in taste:This option is not correct either. As mentioned before, ozone gas does not have a greenish-blue color, and it does not have any taste.
- D. d) Purple-yellow, non-poisonous, non-explosive:This option is not correct. Ozone gas is not purple-yellow in color. It is a pale blue gas, as mentioned earlier. Ozone is non-poisonous at low concentrations, but it can be harmful at higher concentrations. It is not explosive.
Q119. Which one of the following is a lewis acid?
- A. (CH3)3N
- B. PH3
- C. BF3✓
- D. O2
Explanation: BF3 acts as a lewis acid when it accepts the lone pair of electrons that NH3 donates. Hence the correct answer will be C.
Why the other options are wrong
- A. a) (CH3)3N:(CH3)3N, also known as trimethylamine, is a Lewis base. It has a lone pair of electrons on the nitrogen atom that can be donated to form a coordinate bond with a Lewis acid.
- B. b) PH3:PH3, also known as phosphine or phosphorus trihydride, is a Lewis base. It has a lone pair of electrons on the phosphorus atom, which can act as a donor in a coordinate bond with a Lewis acid.
- D. d) O2:O2, also known as molecular oxygen, is not a Lewis acid. It is a stable diatomic molecule, and both oxygen atoms are strongly bonded together by a double bond, without the presence of any vacant orbitals to accept electrons from a Lewis base.
Q120. According to molecular orbital theory, which one of the following will indicate two unpaired electrons?
- A. N2
- B. O2✓
- C. F2
- D. Hc 2+2
Explanation: O2 has two unpaired electrons in its p orbital, hence the correct answer will be B.
Why the other options are wrong
- A. a) N2:N2, also known as nitrogen gas, has a molecular orbital configuration of sigma 2s^2 sigma* 2s^2 pi 2p^4 sigma 2p^2, where the asterisk (*) indicates an antibonding orbital. In this configuration, there are three unpaired electrons, with two of them in the pi 2p molecular orbitals.
- C. c) F2:F2, also known as fluorine gas, has a molecular orbital configuration of sigma 2s^2 sigma* 2s^2 pi 2p^4 pi* 2p^4. In this configuration, there are one unpaired electron in the pi 2p molecular orbital.
- D. d) Hc2+2:Hc2+2 is not a common chemical species, and without further context, it is not clear what its molecular orbital configuration would be. Therefore, we cannot determine the number of unpaired electrons for this option.
Q121. 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.
Why the other options are wrong
- A. a) CaF2:CaF2 is calcium fluoride. It consists of a metal (calcium) and a non-metal (fluorine). In this ionic compound, calcium donates two electrons to each fluorine atom, forming ionic bonds. Therefore, CaF2 does not show covalent bonding.
- B. b) MgO:MgO is magnesium oxide. Similar to CaF2, it consists of a metal (magnesium) and a non-metal (oxygen). The magnesium atom donates two electrons to each oxygen atom, forming ionic bonds. Therefore, MgO does not show covalent bonding.
- C. c) KCl:KCl is potassium chloride. It is also an ionic compound, with potassium donating one electron to chlorine, forming an ionic bond. Therefore, KCl does not show covalent bonding.
Q122. Which one of the following has a covalent bonding by the overlap of sp hybridised orbital with p orbital?
- A. BF3✓
- B. H2O
- C. BeCI
- D. NH3
Explanation: BF3 molecule is formed by bonding between three sp2 orbitals of B and p of 3 F atoms.
Why the other options are wrong
- B. b) H2O:H2O is water. The oxygen atom in water undergoes sp^3 hybridization, resulting in four sp^3 hybrid orbitals. Two of these hybrid orbitals overlap with the s orbitals of two hydrogen atoms to form two sigma bonds, while the other two hybrid orbitals accommodate two lone pairs of electrons. There is no overlap of sp hybridized orbitals with p orbitals in H2O.
- C. c) BeCl2:BeCl2 is beryllium chloride. Beryllium has a ground-state electronic configuration of 1s^2 2s^2. To form two sigma bonds with two chlorine atoms, beryllium undergoes sp hybridization, resulting in two sp hybrid orbitals. However, there is no overlap of these sp hybridized orbitals with p orbitals in BeCl2.
- D. d) NH3:NH3 is ammonia. The nitrogen atom in ammonia undergoes sp^3 hybridization, resulting in four sp^3 hybrid orbitals. Three of these hybrid orbitals overlap with the s orbitals of three hydrogen atoms to form three sigma bonds, while the fourth hybrid orbital accommodates a lone pair of electrons. There is no overlap of sp hybridized orbitals with p orbitals in NH3.
Q123. 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: The root mean square speed is calculated by the formula Vrms = √ v1^+v2^+v3^+v4^ / total no. of molecules Vrms = √8^2+6^2+6^2+√120 / 4 = 6 ms-1
Why the other options are wrong
- B. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q124. 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 reducing agent is stronger when it has a more negative reduction potential, hence the answer will be B.
Why the other options are wrong
- A. this option is incorrect.
- C. c) Small positive values:A small positive value for the reduction potential (E°) indicates a weak reducing agent or a species that is more likely to be oxidized than reduced. It does not have a strong tendency to donate electrons and reduce other species.
- D. d) Large positive values:A large positive value for the reduction potential (E°) indicates a strong oxidizing agent. An oxidizing agent is the opposite of a reducing agent; it readily accepts electrons and gets reduced in a chemical reaction.
Q125. 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.
Why the other options are wrong
- A. a) Imethylglyoxime:Imethylglyoxime is a reagent used for the detection of nickel ions (Ni^2+), not NH4+ ions. It forms a red complex with nickel ions.
- B. b) Tollen's reagent:Tollen's reagent is used to test for aldehydes. It is not suitable for detecting NH4+ ions.
- D. d) Magneson reagent:Magneson reagent is used for the detection of aromatic compounds containing a phenolic group. It is not suitable for detecting NH4+ ions.
Q126. 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: Unpaired d electrons as the d subshell splits and excitation occurs.
Why the other options are wrong
- B. b) Unpaired p electrons:The p orbitals are not directly involved in the variable oxidation states of transition elements. The valence electrons of transition elements are mainly from the d orbitals.
- C. c) Unpaired f electrons:The f orbitals are part of the inner transition elements, which are found in the f-block of the periodic table. They are not directly involved in the variable oxidation states of the transition elements in the d-block.
- D. d) Paired up d electrons:Paired up d electrons do not contribute to variable oxidation states. It is the unpaired d electrons in the transition metal's valence shell that are responsible for different oxidation states.
Q127. 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. 0.0030NA
- B. 0.25 NA✓
- C. 3.0 NA
- D. 4.0 N A
Explanation: We calculate the moles using the formula moles = mass / Mr = 3/12 = 0.25 and then multiply it with NA to find total number of atoms. Number of moles= Mass/ Molar mass= 3/12= 0.25Number of atoms= 0.25NA
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q128. 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 molecular formular for oleum is H2S207, therefore the answer is D.
Why the other options are wrong
- A. a) H2S2O3:H2S2O3 is thiosulfuric acid, and it is not the molecular formula of oleum.
- B. b) H2S2O5:H2S2O5 is not a known compound, and it is not the molecular formula of oleum.
- C. c) H2S2O6:H2S2O6 is not a known compound, and it is not the molecular formula of oleum.
Q129. 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.
Why the other options are wrong
- A. a) Two of its atoms:If EDTA bonds to the central metal atom through two of its atoms, it would be a bidentate ligand. However, EDTA is a polydentate ligand, meaning it can form multiple bonds with the central metal atom.
- B. b) Three of its atoms:If EDTA bonds to the central metal atom through three of its atoms, it would be a tridentate ligand. While EDTA has multiple donor atoms, it can form more bonds than just three.
- C. c) Four of its atoms:If EDTA bonds to the central metal atom through four of its atoms, it would be a quadridentate ligand. Again, while EDTA has multiple donor atoms, it can form more bonds than just four.
Q130. Half cell reaction standard reduction potential, Eo= Fe2+ 2e- → Fe –0.41Cu2+ 2e- → Cu 0.34 Ni2+ 2e- → Ni -0.25 Zn2+ 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: Zn is the only element in the table which has its E0 value more negative then Iron, hence it will prevent iron from corroding by forming a layer of zinc carbonate.
Why the other options are wrong
- A. this option is incorrect because zinc could be used to prevent iron from corrosion.
- C. this option is incorrect because zinc could be used to prevent iron from corrosion.
- D. this option is incorrect because zinc could be used to prevent iron from corrosion.
Q131. Lipids are naturally occurring substances which are chemically:
- A. Proteins
- B. Amino acids
- C. Carbohydrates
- D. Esters✓
Explanation: Lipids are made up of fatty acids and glycerols which are joined together via ester bonds Hence the answer is D
Why the other options are wrong
- A. a) Proteins:Proteins are biomolecules composed of amino acids joined together by peptide bonds. They have important functions in various cellular processes but are not lipids.
- B. b) Amino acids:Amino acids are the building blocks of proteins, but they are not lipids. Lipids are a separate class of biomolecules.
- C. c) Carbohydrates:Carbohydrates are biomolecules composed of carbon, hydrogen, and oxygen atoms. They include sugars and starches but are not lipids.
Q132. 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: ksp = [A+] [ B-]4.0 x 10-4 = [x2]take under root of 4.0 x 10-4 to get the molar solubility of salt as 0.02 M i.e option B
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q133. The primers used in polymerase chain reaction has a sequence of bases
- A. 8
- B. 12
- C. 16
- D. 20✓
Explanation: Primers are single strands of DNA or RNA sequence that are around 20 to 30 bases in length, therefore the answer will be D.
Why the other options are wrong
- A. a) 8:Primers used in PCR are typically longer than 8 bases. They need to be long enough to provide specificity and anneal to the target DNA sequence.
- B. b) 12:Primers used in PCR are usually longer than 12 bases. While 12 bases might provide some specificity, PCR primers are generally longer to ensure accurate and specific binding to the target DNA.
- C. c) 16:Primers used in PCR can have a length of around 16 bases. This length allows for good specificity and annealing to the target DNA sequence.
Q134. Which one is least reactive towards reaction with Na?
- A. CHO3H
- B. CH 3 – CH2 - COOH
- C. CH3 – O- CH 3✓
- D. CH3 - COOH
Explanation: Since CH3 - O - CH3 is inert and it does not contain active group therefore it does not react with sodium.
Why the other options are wrong
- A. a) CHO3H:This compound, written as CHO3H, is a carboxylic acid with the formula HCOOH, which is also known as formic acid. When reacted with sodium (Na), formic acid will release hydrogen gas (H2) due to the displacement of a hydrogen atom by sodium. This reaction is relatively reactive.
- B. b) CH3 – CH2 - COOH:This compound is a carboxylic acid with the formula CH3CH2COOH, known as propanoic acid. When reacted with sodium (Na), propanoic acid will also release hydrogen gas (H2) due to the displacement of a hydrogen atom by sodium. This reaction is relatively reactive.
- D. d) CH3 - COOH:This compound is a carboxylic acid with the formula CH3COOH, known as acetic acid. Like formic acid and propanoic acid, acetic acid will also release hydrogen gas (H2) when reacted with sodium (Na), making this reaction relatively reactive.
Q135. 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.
Why the other options are wrong
- A. Iron (Fe) has a larger atomic radius than copper because it has fewer protons in the nucleus and thus a weaker attractive force on the electrons.
- B. Cobalt (Co) has a larger atomic radius than copper because it also has fewer protons in the nucleus than copper.
- C. Nickel (Ni) has a larger atomic radius than copper because it also has fewer protons in the nucleus than copper.
Q136. 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.
Why the other options are wrong
- A. Copper has a positive temperature coefficient of resistance, which means it's resistance increases as its temperature increases.
- C. Soft iron also has a positive temperature coefficient of resistance.
- D. Platinum also has a positive temperature coefficient of resistance.
Q137. 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.
Why the other options are wrong
- A. a) Leaf-tip:The leaf-tip refers to the apex or topmost part of a leaf. The leaf-tip is not where pulvinus tissues are typically present.
- B. b) Leaf-margin:The leaf-margin refers to the edge or border of a leaf. While some leaves may have specialized tissues along the margin for various functions, pulvinus tissues are not typically found at the leaf margin.
- D. d) Middle-vein:The middle-vein, also known as the midrib, is the central vein that runs down the middle of a leaf, providing support and transportation of water and nutrients. Pulvinus tissues are not typically found along the middle-vein.
Q138. 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: Chain and position isomers have almost similar chemical properties but different physical, whereas functional grp isomers have different chemical and physical properties.
Why the other options are wrong
- A. Chain isomers have the same molecular formula and only differ in the arrangement of the carbon chain, which does not significantly affect their physical or chemical properties.
- B. Position isomers have the same molecular formula and functional groups, and only differ in the position of their atoms or groups, so their Physical and chemical properties are nearly identical.
- D. this option is incorrect.
Q139. 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.
Why the other options are wrong
- A. Bacyer's test is used to distinguish between carbohydrates and ketones.
- B. This option is correct. Fehling's test is used to distinguish between Aldehydes and ketones.
- C. This option is also correct. Silver mirror test is also used to distinguish between Aldehydes and ketones.
Q140. 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; Boltzmnn constant
- B. Avogadro constant; Molar gas constant
- C. Total number of molecules; Boltzmann constant✓
- D. Total number of molecules; Avogadro constant
Explanation: K represents the boltzmann constant 8.31, whereas N is the number of molecules of gas
Why the other options are wrong
- A. "N" represents the number of molecules, not Avogadro's constant. So, this option is incorrect.
- B. This option is also incorrect. "N" represents the number of molecules, not Avogadro's constant, wheareas "k" represents the Boltzmann constant, not molar gas constant.
- D. "k" represents the Boltzmann constant, not Avogadro's constant. So, this option is incorrect.
Q141. 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
Why the other options are wrong
- A. We have to relate gravitational force while R equals radius and when R equals radius plus radius/50
- B. this option is incorrect.
- C. 2500/2601 equals 0.96
Q142. 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.
Why the other options are wrong
- A. Transverse waves that include electromagnetic waves can be polarized
- B. stationary waves as name said are stationary so polarization cannot differentiate them
- D. Longitudinal wave are produced by compression and rarefaction of the medium that can pass through any type of polarizer
Q143. 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 instamtaneously release three neutrons between themselves becoming barium144 and krypton89, therefore the answer is D.
Why the other options are wrong
- A. A neutron is always produced to further undergo fission reaction
- B. When a nucleus fissions, it splits into several smaller fragments. These fragments, or fission products, are about equal to half the original mass. approx.three neutrons are also emitted.
- C. A uranium-235 atom absorbs a neutron and fissions into two new atoms (fission fragments), releasing three new neutrons and some binding energy.
Q144. 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 angle between A and B is ∅The resultant of A + B vector is given as,R = √(A²+B²+2AB cos∅)The resultant of A-B vector is given as,R= √(A²+B²-2AB cos∅)As it is given in question,|A+B| = |A-B|√(A²+B²+2AB cos∅) = √(A²+B²-2AB cos∅)Solving,4ABcos∅ = 0Cos ∅ = 0∅ = 90°
Why the other options are wrong
- A. Cos of 90° is zero.
- B. if Cos∅ =0∅ = anti cos 0 = 90°
- D. This option is incorrect.
Q145. 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, mass number reamins the same but proton number increases by 1. Since there are 2 beta decays, proton number will be increased by 2.Zirconium has 40 protons so proton number will increases from 40 t0 42. Thus option B is correct.
Why the other options are wrong
- A. Atomic number will be increased by two.
- C. In gamma decay , there is no change in atomic number or atomic mass but in question they asked about beta decay which causes increase in atomic number.
- D. In beta decay, there is no change in mass number.
Q146. 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 ms1
- B. 13.3 ms-1
- C. 40 ms-1
- D. 48 ms1✓
Explanation: We have to find average speedAverage speed = distance/timeBut distance is not givenWe will find distance individually,For speed 20ms-¹ in 2s,Distance = speed x timeD1= 20 x 2D1 = 40 mFor speed 40ms-¹in 2s,Distance = speed x timeD2= 40 x 2D2 = 80 For speed 60ms-¹ 6s,Distance = speed x timeD3= 60 x 6D3= 360 mAverage speed= total distance/ total time = 40+80+360 / 2+2+6 = 480 / 10 = 48 ms-¹So right answer is D
Why the other options are wrong
- A. this option is incorrect.
- B. this option is incorrect.
- C. this option is incorrect.
Q147. 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 is one that contains only mass but no direction, therefore the answer is B.
Why the other options are wrong
- A. :If a physical quantity has both magnitude and direction, it is defined as a vector quantity. Because velocity has both magnitude and direction, it is a vector quantity. Therefore, Acceleration is also a vector quantity because it has both magnitude and direction.
- C. Acceleration is a vector quantity
- D. Momentum is the product of mass and velocity of a body. Mass is a scalar, and velocity is a vector. A vector multiplied by a scalar quantity results in a vector. So, momentum is a vector quantity, and its direction depends on that of the object's velocity.
Q148. 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: P = 100kWV = 10kVPower dissipated has formula,P = I²RWe have to find current first,We know,P = VII = P / VI = 100kW / 10kVI = 10 ANow finding power,P = I² RP = 10 x10 x 5P = 500 WSo, C option is right
Why the other options are wrong
- A. there are many formulas to find power but when they ask about power dissipated ,we use I²R
- B. Resistance is given as 5 ohm
- D. 500 W power is dissipated
Q149. Read the statement and choose the correct option
- A. A
- B. B
- C. C
- D. D✓
Explanation: The formula for power is force x velocity so option D is correct.
Why the other options are wrong
- A. This is not the power
- B. power never had this formula.
- C. it is also wrong option.
Q150. 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: Ultraviolet rays do affect photographic plates.
Why the other options are wrong
- A. UV rays do diffract.Diffraction radiation is produced when relativistic particles move near a target. If the target is a crystal or X-ray mirror, diffraction radiation in the X-ray region is expected to be diffracted at the Bragg angle and therefore be detectable. The diffraction of the UV rays in the glass in addition to the use of a non-coherent UV light source cause more glass material to be exposed at the bottom of the glass than at the vicinity of the mask.
- B. All the electromagnetic waves are transverse waves and they can be polarized.
- C. UV has a higher frequency and shorter wavelength than visible light, and it has a lower frequency and longer wavelength than X-radiation. UV with its longer wavelength and less energy is less penetrating than X-ray and is sometimes absorbed by matter.
Q151. 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
Why the other options are wrong
- A. a) GMm/R:This option is not correct. It not only gives the gravitational force (F) between the planet and the body, but also take into account the distance (R) from the center of the planet.
- B. b) GMm/R^2:This option is not correct. It gives the correct formula for the gravitational force (F) between the planet and the body, but it does not consider the mass of the body (m) to calculate the acceleration due to gravity (g).
- D. d) GM/R^2:This option is not correct. It only provides the expression for the acceleration due to gravity (g) at the surface of the planet, but it does not take into account the mass of the body (m) or the distance (R) from the center of the planet.
Q152. 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
Why the other options are wrong
- A. This statement refer to an adiabatic process, where no heat transfer occurs between the system and its surroundings. While, this statement is true for an adiabatic process, it is not a statement of the first law of thermodynamics.
- B. This statement refers to an isothermal process, where the temperature of the system remains constant. While the statement is true for isothermal process, it is not a statement of first law of thermodynamics.
- C. This statement is not a part of the first law of thermodynamics, but rather a statement about the type of Workdone by a system.
Q153. 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.
Why the other options are wrong
- A. This type of voltage conversion is not possible using a transformer because transformers work only with alternating voltages, not direct voltages.
- C. This type of voltage conversion is not possible using a transformer because transformers work only with alternating voltages, not direct voltages.
- D. This is not a typical function of a transformer because transformers work with voltages, not currents.
Q154. 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: Using the formula dsin(θn) = nλ d = 2 × 5 × 10^-7/ sin (30) , n = 2 × 10^-6 N = 1/ 2×10^-6 = 500000m = 500 mmExplanation is also given in image:
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q155. 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: Its up to 3 significant figures.
Why the other options are wrong
- B. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q156. 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.
Why the other options are wrong
- A. The pebble would not stop at the center of the earth because it will experience gravitational attraction from the mass on all sides of it, which will cause it to oscillate back and forth.
- B. The pebble will oscillate back and forth through the center due to gravitational attraction until it comes to rest at the center.
- D. this option is incorrect.
Q157. 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.
Why the other options are wrong
- A. This option is incorrect. The critical frequency is the highest frequency that can be reflected back to earth from the ionosphere.
- C. Work function is a property of a material, which is defined as the minimum quantity of energy which is required to remove an electron to infinity from the surface of a given solid.
- D. this option is incorrect.
Q158. 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
Why the other options are wrong
- A. this option is incorrect.
- B. this option is incorrect.
- C. this option is incorrect.
Q159. 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 at² u = 0, a = g t = 4s g ≈ 10 ms-²Then, s = (0)(4) + ½ (10)(4)² s = 0 + ½ (10)(16) s = ½ (160) s = 80m
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q160. "I saw him yesterday" she said. Select the correct indirect speech:
- 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: The question is in past tense and the option that follows this tense is option B.
Why the other options are wrong
- A. This option is not correct. It uses "told" instead of "said", which changes the meaning slightly. Also, "yesterday" needs to be changed to "the day before" to reflect that it's now in the past.
- C. Thus option changes the meaning of the original statement. "Could see" suggests that she had the ability to see him, but it does not necessarily mean that she did see him. Also, "the previous day" is not a common way to express the past tense in indirect speech.
- D. This option changes the tense of the verb from past tense to future tense, which is not correct. It also changes "saw" to "would see", which again changes the meaning of the original statement.
Q161. 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 - m0.2v P - 0.2p = (m) (v) (0.8) K.E = ½ mv² = ½ m (0.64v²) K.E = 36%
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q162. The antimatter of election is:
- A. Photon
- B. Roton
- C. Positron✓
- D. Antineutrino
Explanation: Antimatter is a type of matter made up of anti particles, positron is the antiparticle for electrons.
Why the other options are wrong
- A. Photons are elementary particles that make up electromagnetic radiation, such as light. They are not considered to have an antimatter counterpart since they are their own antiparticle.
- B. Rotons are collective excitations or quasiparticles that arise in certain types of materials, such as liquid helium. They are not fundamental particles and are not considered to have an antimatter counterpart.
- D. Antineutrinos are produced in certain types of radioactive decay, but they are not directly related to electron processes.
Q163. 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.
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q164. A body in equilibrium must not have:
- A. Kinetic energy
- B. Velocity
- C. Momentum
- D. Acceleration✓
Explanation: A body at equilibrium must have an acceleration of 0m/s2.
Why the other options are wrong
- A. A body in equilibrium can have Kinetic energy, but it must not have any net increase or decrease in its kinetic energy since it is not accelerating.
- B. A body in equilibrium can have velocity, but it must not have any increase or decrease in its velocity since it is not accelerating.
- C. A body in equilibrium can have momentum, but it must not have any net increase or decrease in its momentum since it is not accelerating.
Q165. 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.
Why the other options are wrong
- A. Microwaves have lower energy and longer wavelengths than Infrared radiation. They are typically associated with the rotational energy of molecules.
- C. Visible light has even higher energy and shorter wavelengths than Infrared radiation. It is typically associated with the electronic transitions in molecules.
- D. X-rays have much higher energy and much shorter wavelengths than visible light. They are typically associated with the ionization or excitation of inner-shell electrons in atoms and molecules.
Q166. 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 (each with resistance R) are connected in parallel, the equivalent reaistance is given 1/ Req = 1/R +1/R + 1/R = 3/R So, Req = 3/RWhen the same resistors are connected in series, the equivalent reaistance is the sum of the individual resistances: Req = R + R + R = 3RTherefore, the equivalent reaistance when the three equivalent resistors are connected in series is 3R.
Why the other options are wrong
- B. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q167. Ohm‘s law is valid only for
- A. Thermistor
- B. Bulb filament
- C. Metals✓
- D. Semiconductors
Explanation: Ohms law is valid for metallic conductors, hence the answer will be C.
Why the other options are wrong
- A. A thermistor is a type of resistor whose resistance changes with changes in temperature. Therefore, ohm's law is not valid for thermistors.
- B. Ohm's law is not valid for bulb filament because the resistance of the filament changes with temperature.
- D. Semiconductors such as silicon and germanium have a non-linear relationship between current and voltage. Hence, Ohm's law is not valid for Semiconductors.
Q168. 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: De broglies’ wave equation is used to calculate the wavelength =h / mv hence option B is correct.
Why the other options are wrong
- A. v = fλ is the formula for calculating the velocity.
- C. s = d/t is the formula for calculating the speed of an object that travels a distance (d) in a certain amount of time (t).
- D. This formula relates the momentum (p) of a photon to its wavelength (λ) and planck's constant (h). p = λ × h
Q169. 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: Since E = 1/2 QV, we can write E as 1/2CV2 OR E=Q2/2C thus option D is correct
Why the other options are wrong
- A. ½ CV² is the correct formula for the energy stored in a charged capacitor.
- B. ½ QV is also the correct formula for the energy stored in a charged capacitor.
- C. This option is incorrect. ½ mv² is the formula for the kinetic energy of an object with mass m and velocity v.
Q170. 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 strength of an electric field is calculated viaE = V/d, where V is the potential difference and d is the distance between the plates, hence the answer will be A.
Why the other options are wrong
- B. Separation and area of the plates is not needed in order to find the electric field strength between the plates.
- C. Permittivity of the medium; separation of the plates is not needed in order to find the electric field strength between the plates.
- D. Permittivity of the medium; separation and area of the plates is not needed in order to find the electric field strength between the plates.
Q171. A capacitor which has a capacitance of 1 farad will:
- A. Be fully charged in 1 second by a current of 1 ampere
- B. Store 1 coulomb of charge at a 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 aoross a resistor of resistance 1 ohm
Explanation: A capacitor with a capacitance of one farad will store one coloumb of charge when one volt of potential difference is applied across it.
Why the other options are wrong
- A. This option is not necessarily true because the time it takes for a capacitor to charge depends on the capacitance and the resistance of the circuit.
- C. This option is incorrect because the amount if energy stored in a capacitor is given by ½ CV², where C is the capacitance and V is the potential difference across the capacitor.
- D. This option is not necessarily true because the time it takes for a capacitor to discharge depends on the capacitance and the resistance of the circuit.
Q172. 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.
Why the other options are wrong
- A. The internal energy of a fixed case of an ideal gas does not depend on Pressure, but not volume or temperature.
- C. The internal energy of a fixed case of an ideal gas does not depend on Volume, but not pressure or temperature.
- D. The internal energy of a fixed case of an ideal gas does not depend on Pressure and temperature, but not volume.
Q173. 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 hook's law, the spring force is directly proportional to the displacement of the spring from its equilibrium. F = kx x = 70 - 50 mm x = 20 mm x = 0.02 k = 400 Nm-¹ Tension, F = kx F = 400 (0.02) F = 8 N
Why the other options are wrong
- B. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q174. 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.
Why the other options are wrong
- B. Since 501.85°C is equivalent to 775 K in thermodynamic temperature, this option is incorrect.
- C. Since 501.85°C is equivalent to 775 K in thermodynamic temperature, this option is incorrect.
- D. Since 501.85°C is equivalent to 775 K in thermodynamic temperature, this option is incorrect.
Q175. 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. 2n ms1
- D. 4n2 ms-2✓
Explanation: The formula for acceleration of an object is: a = w²r = s²/r w = 2π As it is the circumference r = 1Then, a = (2π)²(1) a = 4π² ms-²
Why the other options are wrong
- A. this option is incorrect.
- B. this option is incorrect.
- C. this option is incorrect.
Q176. 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: We find the peak value of current using the formula: = I / √2So, = 5 / √2 = 3.53 R = 10ΩThen we find power using the formula: P = I²R = (3.53)²(10) P = 125 W
Why the other options are wrong
- B. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q177. 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. This is because the force of gravity is the only force acting on the body, and the force of gravity is equal to the weight of the body. The rate of change of momentum is given by the following formula: Force = Rate of Change of Momentum where: Force acting on the object Rate of Change of Momentum is the rate at which the momentum of the object is changing The weight of an object is given by the following formula: Weight = Mass * Gravity where: Weight is the force of gravity acting on the object Mass is the mass of the object Gravity is the acceleration due to gravity Substituting the force of gravity into the formula for the rate of change of momentum, we get: Mass * Gravity = Rate of Change of Momentum This means that the rate of change of momentum of a body falling freely under gravity is equal to its weight.
Why the other options are wrong
- A. Impulse is the product of force and time. It is a vector quantity, which means that it has both magnitude and direction. The impulse of a force is given by the following formula: Impulse = Force * Time
- B. Kinetic energy is the energy of an object due to its motion. It is the energy that an object has because it is moving. Kinetic energy is a scalar quantity, which means that it has only magnitude and not direction. The kinetic energy of an object is given by the following formula: K.E. = 1/2 mv²
- C. Power is the rate at which work is done. It is the amount of work done per unit time. Power is a scalar quantity, which means that it has only magnitude and not direction. The power of an object is given by the following formula: Power = Work / Time
Q178. Radioactive activity is affected by:
- A. Temperature
- B. Pressure
- C. Humidity level
- D. None of the above✓
Explanation: Radioactivity is a spontaneous emission and does not depend on nor affected by external conditions such as temperature, air pressure etc. hence the correct answer will be D.
Why the other options are wrong
- A. Radioactive activity is not affected by temperature.
- B. Radioactive activity is also not affected by pressure.
- C. Radioactive activity is also not affected by humidity level.
Q179. 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
Why the other options are wrong
- B. The change in enthalpy at constant pressure, △H is not equal to △H = △E- P△V .
- C. The change in enthalpy at constant pressure, △H is not equal to △H = △E + P△V .
- D. The change in enthalpy at constant pressure, △H is not equal to △H = q - P△V .
Q180. 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. Slightly smaller than 41✓
- B. Slightly larger than 41
- C. Roughly equal to 3/2.
- D. Slightly larger than 21
Explanation: Fundamental wavelength 4xT
Why the other options are wrong
- B. b) Slightly larger than 41:This option suggests that the wavelength of the fundamental mode emitted by the organ pipe is slightly larger than 41 units. it is incorrect.
- C. c) Roughly equal to 3/2:This option suggests that the wavelength of the fundamental mode is roughly equal to 3/2 units. However, again, the units are not specified, and the value 3/2 does not seem to be directly related to the wavelength of the fundamental mode of an organ pipe.
- D. d) Slightly larger than 21:This option suggests that the wavelength of the fundamental mode emitted by the organ pipe is slightly larger than 21 units. Similar to the other options, the units are not specified, making it difficult to determine the exact value.
Q181. 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)
Why the other options are wrong
- A. a) Pb is converted to PbO2:When recharging an automobile battery, the lead-acid battery undergoes a chemical reaction in which lead dioxide (PbO2) is formed on the positive electrode (anode). During the discharge process, lead dioxide (PbO2) is reduced to lead sulfate (PbSO4) and lead (Pb) on the negative electrode (cathode). During the recharge process, the reverse reaction occurs, and lead (Pb) is oxidized back to lead dioxide (PbO2) on the positive electrode.
- B. b) PbSO4 is converted to Pb:This statement is incorrect. During the recharging process, lead sulfate (PbSO4) on the negative electrode is reduced to lead (Pb) and lead dioxide (PbO2) during the charging process. It does not directly convert to lead (Pb).
- D. this option is incorrect.
Q182. 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
Why the other options are wrong
- B. b) 1:This ratio also indicates that the two wires X and Y have the same value. It means that both wires are identical in terms of their length, diameter, and material. This is another way of expressing that the wires are equal.
- C. c) 2:This ratio means that the length of wire Y is twice the length of wire X, but the diameter of wire Y is the same as wire X. So, wire Y is longer than wire X, but they have the same cross-sectional area.
- D. d) 4:This ratio means that the length of wire Y is twice the length of wire X, and the diameter of wire Y is also twice the diameter of wire X. So, wire Y is both longer and
Q183. 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 ha a greater chrge than X
- C. Parallel but opposite
- D. Parallel, opposite and folded spirally.
Explanation: The drag force on the drops is proportional to the square of droplets radii but the weight of the droplets is proportional to its cube, therefore the larger the droplet the heavier it is and will fall faster after the field is removed, in order to keep the droplet in equilibrium when the field is applied, X must have a larger charge than Y, hence the answer will be A.
Why the other options are wrong
- B. b) Y had a greater charge than X:This option contradicts the observation made in the question. It states that drop Y had a greater charge than X, which is inconsistent with the fact that drop X fell more quickly than Y after the electric field was turned off.
- C. c) Parallel but opposite:This option is not relevant to the observation described in the question. It does not provide any explanation or deduction based on the behavior of drops X and Y.
- D. d) Parallel, opposite, and folded spirally:Similar to option c, this option is not related to the given observation and does not provide any deduction.
Q184. 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.
Why the other options are wrong
- B. This option is not correct. Reverberatory furnaces is not used for the production of wrought iron.
- C. This type of furnace is used for the mass production of steel, not for wrought iron production.
- D. This type of furnace is used for producing pig iron, not wrought iron.
Q185. A mass accelerates uniformly 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, if the mass accelerates uniformly, then the net force acting upon the object is inversely proportional to the mass, hence the answer will be B.
Why the other options are wrong
- A. This option is not correct. When the resultant force acting on a mass is zero, it does not accelerate but moves with a constant velocity.
- C. This option is also incorrect. When the resultant force acting on a mass increases uniformly with respect to time, the acceleration of the mass also increases uniformly.
- D. This option is also incorrect. When the resultant force acting on a mass is proportional to the displacement of the mass from a fixed point, the mass undergoes simple harmonic motion.
Q186. 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.
Why the other options are wrong
- A. a) Gamma rays, ultraviolet rays, radio waves:This option arranges the regions in increasing frequency order. Gamma rays have the highest frequency, followed by ultraviolet rays, and finally, radio waves have the lowest frequency.
- B. b) Gamma rays, visible radiation, ultraviolet rays:This option is not in increasing frequency order. It starts with gamma rays, which have the highest frequency, but then it jumps to visible radiation, which has a lower frequency than gamma rays. Ultraviolet rays are mentioned last, which have a higher frequency than visible radiation.
- D. d) Radio waves, visible radiation, infrared radiation:This option is in increasing frequency order. Radio waves have the lowest frequency, followed by visible radiation, and then infrared radiation with higher frequencies.
Q187. 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. No/8
- B. 2No/3
- C. No/3
- D. 7No/8✓
Explanation: One half like is ½ of the original sample so after 3 half lifes ⅛ of the sample will be left which means ⅞ has decayed, therefore the answer will be D.After each half-life, the number of nuclei remaining is halved. Therefore, after one half-life, N0 /2 nuclei remain.After two half-lives, N0/2 × ½ = N0/4 nuclei remain.After three half-lives, N0/2 × ½ × ½ = N0/8 nuclei remain.So, the number of nuclei that have decayed after a time interval of three half-lives is: N0 - N0/8 = 7N0/8 nuclei.
Why the other options are wrong
- A. this option is incorrect.
- B. this option is incorrect.
- C. this option is incorrect.
Q188. 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: The equation for diffraction grating is: dsin = mλFor the second order of X: dsin = 2λAnd for the third order of Y: dsin = 3λSince they coincide, 2λ = 3λ λ/λ = 3/2Hence, the correct answer will be C.
Why the other options are wrong
- A. this option is incorrect.
- B. this option is incorrect.
- D. this option is incorrect.
Q189. 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 formula for the phase difference between two points in a wave is given by: ∆φ = 2π∆x/λwhere ∆x is the distance between the two points, and λ is the wavelength of the wave. The wavelength of the sound wave can be calculated using the formula: λ = v/fwhere v is the speed of the wave and f is the frequency of the wave.Substituting the given values, we get: λ = 320/400 = 0.8m ∆x = 0.2m ∆φ = 2π (0.2)/0.8 = π/2 radiansTherefore, the phase difference between the two points 0.2 m apart in the direction of the travel is π/2 radians
Why the other options are wrong
- A. this option is incorrect.
- C. this option is incorrect.
- D. this option is incorrect.
Q190. 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 = Force/Area P = F/A = ma/m² = Kg (ms-²)/m² P = Kgm-¹s-²
Why the other options are wrong
- A. Kgms-¹ is the unit of momentum, not pressure.
- C. Kgm²s-² is the unit of energy or work, not pressure.
- D. This option is also incorrect. It is not the unit of pressure.
Q191. 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.
Why the other options are wrong
- A. a) V ∞ r^2 (V is proportional to r^2):This option suggests that the speed (V) of a satellite is proportional to the square of the radius (r) of its orbit. This relationship is incorrect. In reality, the speed of a satellite is not proportional to the square of the radius of its orbit.
- B. b) V ∞ r (V is proportional to r):This option suggests that the speed (V) of a satellite is proportional to the radius (r) of its orbit. This relationship is also incorrect. The speed of a satellite is not directly proportional to the radius of its orbit.
- C. c) V1 ∞ 1/r (V1 is proportional to 1/r):This option suggests that the initial velocity (V1) of a satellite is inversely proportional to the radius (r) of its orbit. This relationship is not accurate. The initial velocity of a satellite is determined by factors such as the launch velocity and the escape velocity required for the orbit.
Q192. 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.
Why the other options are wrong
- B. Wavelength is related to the frequency and speed of the wave by the equation: wavelength = speed/frequency. Therefore, wavelength is not independent of the other wave properties.
- C. The speed of the wave is also related to the wavelength and frequency by the equation: speed = wavelength × frequencyTherefore, speed is not independent of the other wave properties.
- D. Frequency is the number of cycles or oscillations of a wave that occur in one second, which is independent of other wave properties such as amplitude, wavelength, and speed.
Q193. 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: Since the charge is morving parallel to magnetic field, hence the froce will be zero. As the angle will be 0o and sin(0)o is 0.
Why the other options are wrong
- A. This option is not correct since the charge is moving parallel to magnetic field.
- B. this is not the formula of magnetic field.
- D. The given formula is for centripetal force.
Q194. Have you got a computer? She said. Select the correct indirect speech:
- A. She wanted to find whether I have a computer
- B. She wanted to know whether I had a computer.✓
- C. She wanted to know if I could use computer.
- D. She was interested to know about my computer.
Explanation: The tone is interrogatory and the only option that seems coherent with the question is option B.
Why the other options are wrong
- A. This is not correct indirect speech because the tense of the reported speech is not changed from present tense to past tense. The correct tense shift for reported speech would be to change "have" to "had".
- C. This is also not the correct indirect speech because it changes the question from whether the speaker has a computer to whether the speaker can use a computer.
- D. This is also not the correct indirect speech because it changes the question from whether the speaker has a computer to the speaker's computer in particular.
Q195. Add some milk and sugar ...... the tea.
- A. To
- B. At
- C. In✓
- D. On
Explanation: Milk and sugar are always added 'in' the tea so option C is correct.
Why the other options are wrong
- A. This preposition is also not used here. So, this option is incorrect.
- B. "At" is not the correct preposition to use in this sentence. "At" is used to indicate a location, not a direction, so it doesn't make sense to use it in this context.
- D. "On" is not the correct preposition to use in this sentence. "On" is used to indicate that something is physically resting on top of something else, which doesn't make sense in the context of adding milk and sugar in the tea.
Q196. "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 an indirect or passing reference, therefore the answer will be B.
Why the other options are wrong
- A. This definition is not accurate for the term "Allusion".
- C. This definition is also not accurate for the term "Allusion".
- D. This definition is also not accurate for the term "Allusion".
Q197. '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 get control of ones’ thoughts and emotions and stop acting in a foolish or uncontrolled way, hence the answer is C.
Why the other options are wrong
- A. This option is not related to "Get a hold of oneself".
- B. This option is also not related to the "Get a hold of oneself"
- D. This option is also not correct. It is not related to the " Get a hold of oneself"
Q198. 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.
Why the other options are wrong
- A. This sentence has the wrong word order. The adverb "hardly" should be placed before the verb "seem" to modify it properly.
- C. These both options have the wrong word order. So, these options are incorrect.
- D. These both options have the wrong word order. So, these options are incorrect.
Q199. 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: Precise is the gist of a passage expressed in as few words as possible containing all the essential points. Therefore the answer will be D.
Why the other options are wrong
- A. This option is not correct. Precise does not means a synopsis for writing an essay in a degree level examination.
- B. This option also does not describe the meaning of precise.
- C. A resume of the commercial achievements spread over a year is also not a correct statement.
Q200. 'I have been to Spain,' he told me. Select the correct indirect speech:
- 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: The answer is C which has the correct past tense.
Why the other options are wrong
- A. This sentence is not the correct indirect speech. It changes the meaning of the original sentence, as it suggests that he may visit Spain in the future, while the original sentence implies that he already went to Spain in the past.
- B. This sentence is not the correct indirect speech. The past perfect tense "has visited" should be changed to the past perfect tense "had been" to reflect that the action was completed before the time of reporting.
- D. This sentence is also not the correct indirect speech. The present perfect tense "has been" should be should be changed to the past perfect tense "had been" to reflect that the action was completed before the time of reporting.
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