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Fmdc 2015 — Solved Past Paper with Answers

All 149 MCQs from Fmdc 2015, solved with the correct answer highlighted and a full explanation for every question. This is a free MDCAT Federal / FMDC past paper — no signup, no ads. Practise it interactively in timed mode, drill more with free MDCAT MCQs, or browse all Federal / FMDC papers.

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Q1. Fill in the blank.The culpable child _ some words to her mother for pardoning his delinquency.

A. Mumbled✓
B. Showy
C. Rude
D. Crazy

Explanation: “Mumbled” means to speak unclearly and softly, usually when someone feels guilty, shy, or afraid. A culpable (guilty) child asking for pardon would naturally speak in a hesitant, low, unclear way. That makes mumbled the most natural verb for this situation.

Why the other options are wrong

B. 'Showy’ means having a striking appearance or style, typically by being excessively bright, colorful, or ostentatious.
C. 'Rude’ means to be offensively impolite or bad-mannered.
D. 'Crazy' means mad, especially as manifested in wild or aggressive behavior.

Q2. Fill in the blank.The parents stunned when they saw that children had created complete _ in the bedroom.

A. Knack
B. Groggy
C. Dank
D. Mayhem✓

Explanation: “Mayhem” means total chaos, disorder, or mess. When parents see a bedroom completely destroyed or wildly messy by children, mayhem perfectly describes that scene. It fits the idea of a room turned upside down with toys everywhere.

Why the other options are wrong

A. 'Knack’ means a tendency to do something. This is irrelevant for the question.
B. 'Groggy’ means dazed, weak, or unsteady, especially from illness, intoxication, sleep, or a blow.
C. 'Dank’ means unpleasantly damp and cold.

Q3. Fill in the blank. I _ caution in interpreting these results.

A. Urge✓
B. Usher
C. Usurp
D. Uproot

Explanation: As a noun, urge means a desire. As a verb, it means to strongly encourage. Urge is related to the word, urgent, or 'pressing. ' An urge is a pressing want, one that is almost a compulsion, like when you're so frustrated, you have the urge to scream. If you urge someone to do something, you feel strongly about it.

Why the other options are wrong

B. Usher means to guide or escort someone. It doesn't fit the context of caution in interpreting results.
C. Usurp means to take someone's position or power by force or without legal right. It doesn't fit the context of caution in interpreting results.
D. Uproot means to remove or displace something, usually in a literal sense. It doesn't fit the context of caution in interpreting results.

Q4. Fill in the blankThey sometimes feel a _ for the mountains and the sea.

A. Yearning✓
B. Yapping
C. Yelling
D. Yielding

Explanation: Yearning: a feeling of intense longing for something.Phrase: "He felt a yearning for the mountains"

Why the other options are wrong

B. Option B: ‘yapping’ means to give a sharp, shrill bark.
C. Option C: ‘yelling’ means shout in a loud, sharp way.
D. Option D: ‘yeilding’ means giving a product or generating a financial return of a specified amount.

Q5. Fill in the blank.The new teacher showed no _ about hitting the students.

A. Quakes
B. Qualms✓
C. Quarrel
D. Quotation

Explanation: “Qualms” means feelings of doubt, guilt, or moral hesitation. The sentence says the teacher had no hesitation or no sense of guilt about hitting students, which makes qualms the exact fit.

Why the other options are wrong

A. 'Quakes’ means to shake or tremble. This doesn't fit the context of the question.
C. 'Quarrel’ means a heated argument or disagreement, typically about a trivial issue and between people who are usually on good terms.
D. 'Quotation’ means a group of words taken from a text or speech and repeated by someone other than the original author or speaker.

Q6. Fill in the blankThe accident happened due to the driver’s _

A. Negligence✓
B. Reluctance
C. Regret
D. Quotation

Explanation: Negligence: failure to take proper care over something.Phrase: "His injury was due to the negligence of his employers"

Why the other options are wrong

B. Reluctance means unwillingness or hesitation. It doesn't fit the context of the accident happening.
C. Regret refers to feeling sorry or remorseful. While it could be related to the accident, negligence is a more suitable choice.
D. Quotation refers to a passage or statement from a source. It doesn't fit the context of the accident happening.

Q7. Select the nearest correct meaning of the given word.BOWDLERIZE:

A. Mesmerize
B. Cynosure
C. Censure
D. Censor✓

Explanation: Censor means to remove or modify parts of a text or speech that are considered to be offensive or objectionable. It comes from the Latin word "censere," which means "to judge". Both words refer to the act of removing or modifying parts of a text or speech. However, bowdlerize is specifically used to refer to the removal of offensive or objectionable material, while censor can also be used to refer to the removal of material for other reasons, such as to protect national security or to prevent the spread of misinformation.

Why the other options are wrong

A. Mesmerize means to hypnotize or fascinate someone. It comes from the name of Franz Mesmer, a 18th-century Austrian physician who developed a method of treating illness by inducing a trance-like state in his patients.
B. Cynosure means the center of attention or attraction. It comes from the Greek word "kynosure," which means "dog star." The dog star is Sirius, the brightest star in the sky.
C. Censure means to criticize or disapprove of something strongly. It comes from the Latin word "censura," which means "judgment."

Q8. Select the nearest correct meaning of the given word.BRASSY:

A. Tasteful
B. Brainy
C. Modesty
D. Gaudy✓

Explanation: Gaudy means excessively bright, showy, or ornate. A gaudy person or thing would be someone or something that is very flashy and attention-seeking. Gaudy clothing might be covered in sequins or bright colors, and gaudy decor might be very ornate and over-the-top.In the context of the question, the word brassy is being used to describe someone who is loud and confident, but in a way that is not necessarily tasteful or refined. Therefore, the closest meaning of the word brassy in the question is gaudy.

Why the other options are wrong

A. Tasteful means having good taste or judgment in matters of art, style, or fashion. A tasteful person would be someone who dresses well, chooses decor that is not too flashy, and generally has an eye for what looks good.
B. Brainy means intelligent or intellectually gifted. A brainy person would be someone who is good at school, enjoys learning new things, and is generally considered to be intelligent.
C. Modest means humble or unassuming. A modest person would be someone who does not brag about their accomplishments, does not dress in flashy clothes, and generally does not draw attention to themselves.

Q9. Choose the right option to complete the following sentence:All the _ and ceremony of the royal marriage was telecast on TV.

A. Festival
B. Pomp✓
C. Happiness
D. Romp

Explanation: Option A would not fit very well into the given sentence, as a festival in itself is a certain event and would not particularly be used to describe the royal marriage, ‘festivities’ would be a much better fit.Option B means ‘ceremony and splendid display’, and is often used in conjunction with ceremony as a phrase, i.e. ‘pomp and ceremony’ to describe an event such as the royal marriage, hence it is correct.Option C, happiness, would not fit well as it is an emotion which can’t really be directly telecast on TV.Option D describes ‘playing roughly or energetically’.

Why the other options are wrong

A. 'Festival’ means an organized series of concerts, plays, or films, typically one held annually in the same place, which is the same as ceremony; hence it is not correct to say ‘festival and ceremony’.
C. 'Happiness’ is incorrect because it cannot be shown on the tv.
D. 'Romp’ means to play roughly and energetically, its would not fit in the sentence.

Q10. Choose the right option to complete the following sentence:A glue produced by bees to _ their hives appears to contain antibiotic substances.

A. Build✓
B. Decorate
C. Collect
D. Structure

Explanation: The glue in this scenario would be likened to cement in this case, whereby it is used to construct or build the structure in question, hence option A is correct.Options B, decorate and C, collect, would not fit in this context as glue is not a decorating item and nor are hives collected by glue.Option D is similar to A, but it can be used to describe a building in addition to describing the construction of something, so build would be more suitable in this case.

Why the other options are wrong

B. Decorate: Bees do not use glue to decorate their hives. This option does not fit the context.
C. Collect: Bees collect pollen and nectar, but they do not use glue for this purpose. This option does not fit the context.
D. Structure: While the bees use wax to structure their hives, glue is not used specifically for this purpose. This option does not fit the context.

Q11. Spot the error in the following sentence. It should also help you to understand how can you make better use of the scientific method in your everyday living.

A. To understand
B. Can you✓
C. Use of
D. Living

Explanation: "can you": The phrase "can you" is grammatically incorrect in this sentence. It should be replaced with the word "to" to form a correct sentence. The corrected sentence would be: "how to." The underlined segment that contains the mistake is: "how can you make better use of the scientific method in your everyday living." The corrected sentence would be: "It should also help you understand how to make better use of the scientific method in your everyday life." Mistake: The phrase "can you" should be replaced with "to" to form a grammatically correct sentence.

Why the other options are wrong

A. To understand is the infinitive form of the verb "understand". It is used to express the purpose of the sentence. In this case, the sentence is saying that the information should help you to understand something.
C. The phrase "use of" is used correctly in the original sentence. It indicates the utilization or application of something, in this case, the scientific method. There doesn't seem to be a mistake in this segment.
D. Living is a noun that refers to the state of being alive. In this case, the noun is being used as an adjective to modify the noun "everyday". However, the correct form of the adjective is "life".

Q12. Identify the mistake that needs to be corrected.We wished today was sunny so that we could spend the day in the country communicating with nature.

A. Was✓
B. So that
C. Could spend
D. In the country

Explanation: Instead of 'was', 'were' should have been used. We wish today were sunny..These phrases are never correct: I wish I was, I wish it was, he wishes he was, she wishes she was. Always remember this rule about the usage of was and were: use were with expressions that are hypothetical, wishful, imagined, desired, doubtful, and otherwise contrary to fact—that is to say, not real.

Why the other options are wrong

B. The word "so that" is used to introduce a purpose clause. It is a conjunction that shows the purpose of the action in the main clause. In this sentence, the main clause is "We wished today were sunny". The purpose clause is "so that we could spend the day in the country communicating with nature". The word "so that" is correct in this sentence.
C. The word "could" is used to indicate possibility. It is a modal verb that shows that the action is possible but not certain. In this sentence, the action is "spend the day in the country communicating with nature". The word "could" is correct in this sentence.
D. The word "in the country" is used to indicate location. It shows that the action is taking place in the countryside. In this sentence, the action is "spend the day communicating with nature". The word "in the country" is correct in this sentence.

Q13. In the following question four alternative sentences are given. Choose the CORRECT option:

A. Christopher could not taste the drink until he had boiled it.✓
B. Until he had boiled It, Christopher could not taste the drink
C. Christopher could not taste the drink until he had not boiled it.
D. Christopher could not taste the drink till he had not boil it.

Explanation: This is the correct option because it uses the correct tense and word order. The verb "could not taste" is in the past tense, and the phrase "until he had boiled it" is in the past perfect tense. This correctly indicates that Christopher could not taste the drink until after he had boiled it.

Why the other options are wrong

B. This option is incorrect because the word "It" is not clear. It is not clear what "It" refers to. The sentence could be referring to the drink, the water, or something else.
C. This option is incorrect because the word "not" is in the wrong place. The correct word order is "could not taste the drink until he had boiled it." The word "not" should come before the verb "taste."
D. This option is incorrect because the word "till" is not the same as "until." The word "till" is used to refer to a specific time in the future, while the word "until" is used to refer to a point in time before something else happens. In this sentence, the word "until" is the correct word to use because it is referring to the point in time before Christopher could taste the drink.

Q14. Identify errors in the sentence. “All is well what ends well”, said the father when he had finished the story.

A. Is well what✓
B. Said the
C. When he had
D. The story

Explanation: ‘All is well when it end’s well’ is the correct phrase which is used to say that a person can forget about how unpleasant or difficult something was because everything ended in a good way.

Why the other options are wrong

B. Option B is not incorrect. It is grammatically correct to say "said the father" to attribute the statement to him.
C. Option C is not incorrect. It is grammatically correct to use "when" to indicate the time at which the father made the statement.
D. Option D is not incorrect. "The story" is a valid noun phrase that refers to the specific story being discussed in the sentence.

Q15. Identify errors in the sentence. Rubber tubes upon which children had swing in backyards hung suspended like stopped clock pendulums in the blazing air.

A. Upon which
B. Had swing in the backyards✓
C. Suspended like
D. In the

Explanation: “Had swing” is wrong. We always use the third form of the verb with has/have/had.

Why the other options are wrong

A. Option A is not incorrect. "Upon which" is a grammatically correct phrase that indicates the tubes are the surfaces on which the children had swung.
C. Option C is not incorrect. "Suspended like" is a valid phrase that compares the state of the rubber tubes hanging to the appearance or motion of stopped clock pendulums.
D. Option D is not incorrect. "In the blazing air" is a valid phrase that describes the environment or atmosphere in which the rubber tubes were hanging.

Q16. Identify the incorrect part of the sentence.The child was fully dressed and sitting in her father’s lap near the kitchen table.

A. Fully
B. Sitting in✓
C. Kitchen table
D. No error

Explanation: ‘Sitting in’ is not correct. The word ‘father’ suggests the use of ‘sitting on’ instead.If there had been the word ‘mother’ in the sentence, then we would have chosen ‘sitting in’.

Why the other options are wrong

A. “Fully” is not incorrect because it correctly modifies “dressed.”“Fully dressed” is a standard, idiomatic phrase meaning “completely clothed.”So that part is grammatically fine.
C. Why not “kitchen table” as the incorrect part?Because “kitchen table” is perfectly correct and normal English. It means the table that is in the kitchen. There is no grammatical error in that phrase.
D. There is error in the question so this is incorrect.

Q17. Identify the incorrect part of the sentence.The three Abdul Rahman, like his illustrious predecessor, was a young man of twenty-three when he took office.

A. The three✓
B. Like his
C. Was a
D. When he

Explanation: “The three” is a wrong use as “the” is not used to describe a proper noun like it is done in this case. The correct use would have been “Abdul Rahman the third”.

Why the other options are wrong

B. “Like his” is correct because it properly compares Abdul Rahman to his predecessor. The error is “The three Abdul Rahman”, since “three” is incorrect before a singular name — it should be “The third Abdul Rahman.”
C. “Was a” is wrong because the subject is plural: The three Abdul Rahman (three people) → they were, not he was.With a plural subject, you must use “were”, not “was a”.
D. “When he” is not the error because the clause is correct.It properly introduces the time he assumed office, so it’s grammatically fine.

Q18. Identify errors in the sentence. Enlarged and beautified by later Caliphs, Al-Zahra become the nucleus of a royal suburb whose remains partly evacuated in and after 1910, can still be seen.

A. By later
B. Become the✓
C. Whose remains
D. In and after

Explanation: ‘Enlarged’, ‘beautified’, ‘evacuated’ shows the sentence is in past tense hence ‘became’ should be used instead of ‘become’.

Why the other options are wrong

A. Option A: "By later" is correct. It indicates that the enlargement and beautification of Al-Zahra were carried out by later Caliphs.
C. Option C: "Whose remains" is correct. It introduces the possessive form of "remains" and correctly indicates that the remains belong to the royal suburb.
D. Option D: "In and after" is correct. It indicates the time period during which the remains of the royal suburb were partly evacuated, both during and after 1910.

Q19. The division of biology that deals with classification is:

A. Cytology
B. Histology
C. Botany
D. Morphology
E. Taxonomy✓

Explanation: The correct answer is Taxonomy. Taxonomy is the branch of biology concerned with the classification, naming, and organization of living organisms into hierarchical structures such as species, genus, and family. This systematic approach allows scientists to identify and communicate about organisms effectively.Cytology focuses on cells, Histology on tissues, Botany on plants, and Morphology on the form and structure of organisms, none of which directly involve the classification of all living organisms. Thus, they do not fulfill the role of taxonomy.

Why the other options are wrong

A. Option A: ‘Cytology’ focuses on the examination and study of individual cell types, especially those found in fluid specimens. It does not deal with classification.
B. Option B: ‘Histology’ involves the study of the microscopic structure of tissues and organs. It is not related to the classification of organisms.
C. Option C: ‘Botany’ is the study of plants, including their structure and biochemical processes. While it involves studying organisms, it does not primarily focus on classification.
D. Option D: ‘Morphology’ deals with the form and structure of organisms, but it does not specifically address classification.

Q20. All the following are organelles EXCEPT the:

A. Endoplasmic reticulum
B. Mitochondria
C. Ribosomes
D. Golgi complex
E. Ultracentrifuge✓

Explanation: Ultra centrifuge is not an organelle; it is a very fast centrifuge used to precipitate large biological molecules from solution or separate them by their different rates of sedimentation.

Why the other options are wrong

A. The endoplasmic reticulum (ER) is a dynamic organelle responsible for many cellular functions, including the synthesis of proteins and lipids, and regulation of intracellular calcium levels.
B. Mitochondria are membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell's biochemical reactions.
C. They are non-membranous cell organelles that are sub-spherical in shape. Ribosomes are large nucleoproteins that consist of both RNAs and r-proteins.
D. The Golgi complex prepares proteins and lipid (fat) molecules for use in other places inside and outside the cell. The Golgi complex is a cell organelle.

Q21. The diagram shows a section through a kidney and associated blood vessels.In which area is there the greatest movement of fluid from the blood through the wall of blood vessels?

A. A
B. B
C. C
D. D
E. E✓

Explanation: E is the renal cortex. It has the greatest blood flow in the following options. The cortex requires about 80% of blood flow to achieve its excretory and regulatory functions, and the outer medulla receives 15%. The inner medulla receives a small percent of blood flow; a higher flow would wash out solutes responsible for the high tonicity of the inner medulla.

Why the other options are wrong

A. Area A might be a part of the kidney, but it does not have the highest rate of blood filtration.
B. Area B is not where the majority of fluid filtration occurs in the kidney.
C. Area C might be involved in fluid movement, but not the primary site of filtration from blood.
D. D is not the area of greatest fluid movement through vessel walls in the kidney.

Q22. The diagram is taken from an electron of a cell, name the organelle labeled D:

A. Nucleus
B. Lysosomes
C. Golgi complex
D. Mitochondria✓
E. Endoplasmic reticulum

Explanation: Mitochondria are bean- shaped membrane bounded organelles. Cristae is the fold in the inner membrane of mitochondria which is visible in the picture.

Why the other options are wrong

A. This is not correct.it is not nucleus
B. A is lysosomes originating from golgi complex.
C. B is golgi complex. Golgi complex helps in the modification of proteins into glycoprotein or lipoprotein.
E. C is endoplasmic reticulum in diagram

Q23. Of the following organic compounds, the one that represents a protein is

A. C12 H22 O33
B. C6 H12 O6
C. C17 H14 COOH
D. (C6 H12 O5 )13
E. C108 H1130 O224 N180 S4✓

Explanation: Proteins are organic compounds that consist of carbon, hydrogen, oxygen, nitrogen, and, in some cases, sulfur. Rest of the options only have carbon hydrogen and oxygen.

Why the other options are wrong

A. Option A (C12 H22 O33): This compound has a high ratio of oxygen to carbon and hydrogen, suggesting it may be a carbohydrate rather than a protein. Proteins contain carbon, hydrogen, oxygen, and nitrogen, but this compound does not include nitrogen.
B. Option B (C6 H12 O6): This compound is glucose, a carbohydrate commonly known as a sugar. While glucose is an essential component of many biological processes, it is not a protein. Proteins are composed of amino acids, not sugars.
C. Option C (C17 H14 COOH): This compound is a carboxylic acid. It does not contain nitrogen, which is an essential element in proteins. Therefore, it is not a protein.
D. Option D ((C6 H12 O5)13): This compound is a complex carbohydrate known as starch. It is not a protein because it lacks nitrogen. Proteins are composed of amino acids and always contain nitrogen.

Q24. In which of the following is the organic compound COOH (carboxyl) group found? (I) Carbohydrate (II) Lipid (III) Protein

A. I only
B. II only
C. I and II only
D. II and III only✓
E. I , II and III

Explanation: Carboxyl groups are commonly found in amino acids, fatty acids, and other biomolecules. Whereas carbohydrates only contain atoms of carbon hydrogen and oxygen they don't have any functional group.

Why the other options are wrong

A. Carbohydrates usually contain a carbonyl (=O) and hydroxyl (−OH) functional group.
B. Although the compositions of lipids vary, the most common functional groups are ester (both carboxylate and phosphate) and alcohol groups.
C. Carbohydrates usually contain a carbonyl (=O) and hydroxyl (−OH) functional group. Although the compositions of lipids vary, the most common functional groups are ester (both carboxylate and phosphate) and alcohol groups.
E. 1 does not contain carboxylic group.

Q25. Genes P, Q, R, and S occur on the same chromosome.Investigation of a large population produced the following cross-over values between pairs of genes.P and R 34% P and Q 59% R and S 12% S and Q 37% Which of the following sequences represents the sequence of genes on the chromosome?

A. PRSQ
B. PSRQ✓
C. QSPR
D. RQSP
E. SPRQ

Explanation: The correct sequence of genes on the chromosome is PSRQ. This arrangement makes sense given the crossover values provided:The low crossover value of 12% between R and S indicates they are closely linked, which is consistent with having them next to each other in this sequence.The higher crossover value of 59% between P and Q suggests they are further apart on the chromosome, which is also supported in this arrangement.The other options (PRSQ, QSPR, RQSP, SPRQ) do not appropriately reflect the crossover data, leading to contradictions with the provided percentages.

Why the other options are wrong

A. This arrangement suggests P and R are adjacent, which contradicts the high crossover value of 59% between P and Q. Therefore, this option is unlikely to be correct.
C. This arrangement places Q at the beginning, which does not support the high crossover value between P and Q (59%). Thus, this option is incorrect.
D. This sequence places R before S, which is inconsistent with the low crossover value of 12% between R and S. Therefore, this option is also incorrect.
E. This arrangement suggests S is adjacent to P, conflicting with the high crossover value of 59% between P and Q. Hence, this option is not correct.

Q26. Which of the following kinds of atoms do not occur in carbohydrates?

A. Carbon
B. Hydrogen
C. Nitrogen✓
D. Oxygen

Explanation: Carbohydrates are composed of carbon, hydrogen and carbon atoms. Nitrogen is found in fatty acids and amino acids.

Why the other options are wrong

A. Carbohydrates are composed of carbon, hydrogen, and oxygen and have a general formula that approximates CH2O.
B. Carbohydrates are composed of carbon, hydrogen, and oxygen and have a general formula that approximates CH2O.
D. Carbohydrates are composed of carbon, hydrogen, and oxygen and have a general formula that approximates CH2O.

Q27. Smooth muscle develop from:

A. Endoderm
B. Ectoderm
C. Mesoderm✓
D. None of above

Explanation: Smooth muscle in the wall of the gut derivatives is derived from the splanchnic layer of lateral plate mesoderm that surrounds these structures. Only the sphincter and dilator muscles of the pupil and muscle tissue in mammary and sweat glands are derived from ectoderm.The endoderm constructs the digestive tube and the respiratory tube.

Why the other options are wrong

A. The endoderm gives rise to the digestive system and other internal organs.
B. The ectoderm gives rise to the nervous system and the epidermal skin cells.

Q28. Which cell does not carry out oxidative phosphorylation?

A. Nerve cell
B. Cardiac cell
C. Red blood cell✓
D. None of above

Explanation: Red blood cells lack mitochondria and are therefore unable to carry out oxidative phosphorylation.

Why the other options are wrong

A. Oxidative phosphorylation in mitochondria produces ATP by using oxygen to drive the electron transport chain. This ATP is essential for neuronal activity, as it fuels processes like action potential propagation and neurotransmitter release under normal oxygen levels.
B. Cardiac cells, like other muscle cells, have high energy demands due to their continuous contraction and relaxation to pump blood. Therefore, they heavily rely on oxidative phosphorylation to produce ATP efficiently and meet their energy needs.
D. Red blood cells lack mitochondria, so they cannot perform oxidative phosphorylation. Instead, they generate ATP through anaerobic glycolysis to meet their energy needs.

Q29. RNA _ a double stranded molecule.

A. Is
B. Is not✓
C. Is always
D. Depending on its location it is

Explanation: DNA is a double stranded molecule whereas RNA is single stranded.

Why the other options are wrong

A. RNA is a single stranded molecule.
C. RNA is a single stranded molecule.
D. RNA is always a single stranded molecule.

Q30. In DNA, guanine forms a base pair while adenine forms a pair with _

A. Cytosine … thymine✓
B. Thymine … cytosine
C. Uracil … guanine
D. Guanine … uracil

Explanation: The four bases in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). These bases form specific pairs (A with T, and G with C).

Why the other options are wrong

B. This option is incorrect as within a double-stranded DNA molecule, adenine (A) forms hydrogen bonds with thymine (T), and cytosine (C) forms hydrogen bonds with guanine (G).
C. This option is incorrect as within a double-stranded DNA molecule, adenine (A) forms hydrogen bonds with thymine (T), and cytosine (C) forms hydrogen bonds with guanine (G).
D. This option is incorrect as within a double-stranded DNA molecule, adenine (A) forms hydrogen bonds with thymine (T), and cytosine (C) forms hydrogen bonds with guanine (G).

Q31. An enzyme – substrate is the place where enzyme are

A. Formed
B. Deactivated
C. Active✓
D. Reduced
E. Diluted

Explanation: When an enzyme binds its substrate, it forms an enzyme-substrate complex. This complex lowers the activation energy of the reaction and promotes its rapid progression by providing certain ions or chemical groups that actually form covalent bonds with molecules as a necessary step of the reaction process.

Why the other options are wrong

A. Option A (Formed): Enzymes are typically formed or synthesized in cells, not at the enzyme-substrate interface.
B. Option B (Deactivated): The enzyme-substrate interface is the site of enzymatic activity, not deactivation.
D. Option D (Reduced): The term "reduced" refers to a specific chemical reaction involving the transfer of electrons, which is not directly related to the enzyme-substrate interface.

Q32. All viruses

A. Carry DNA
B. Carry RNA
C. Lack protein
D. Have chromosome
E. Cannot reproduce outside cell✓

Explanation: Viruses cannot replicate unless absorbed by cells in our body. Once a virus is outside the body, its capsid starts to degrade, and the more degraded its capsid is, the less likely it is to survive.Option A and B: some viruses carry DNA while some carry RNA.Option C: There are all sorts of virus shapes and sizes. However, all virus particles have a protein coat that surrounds and protects a nucleic acid genome.Option D: Viruses do not have chromosomes

Why the other options are wrong

A. Viruses are smaller and simpler in construction than unicellular microorganisms, and they contain only one type of nucleic acid—either DNA or RNA—never both.
B. Viruses are smaller and simpler in construction than unicellular microorganisms, and they contain only one type of nucleic acid—either DNA or RNA—never both.
C. The essential components of infectious viral particles are nucleic acid (the genome) and protein.
D. Viruses do not have chromosomes in the traditional sense.

Q33. The correct sequence of steps in koch’s postulate is (I) Injecting the germ, to produce original disease (II) Isolating the same germ in many cases (III) Obtaining the original germ from infected animals (IV) Growing the germ in pure culture

A. I –> IV –> II –> III
B. I –> II –> III –> IV
C. II –> IV –> I –> III
D. II –> I –> IV –> III
E. III –> IV –>I –> II✓

Explanation: In only option E the correct sequence is mentioned.

Why the other options are wrong

A. The correct sequence is 3,4,1,2.The correct sequence of steps in Koch's postulate is:(I) Obtaining the original germ from infected animals(II) Growing the germ in pure culture(III) Injecting the germ to produce the original disease(IV) Isolating the same germ in many cases
B. The correct sequence is 3,4,1,2. The correct sequence of steps in Koch's postulate is:(I) Obtaining the original germ from infected animals(II) Growing the germ in pure culture(III) Injecting the germ to produce the original disease(IV) Isolating the same germ in many cases
C. The correct sequence is 3,4,1,2.The correct sequence of steps in Koch's postulate is:(I) Obtaining the original germ from infected animals(II) Growing the germ in pure culture(III) Injecting the germ to produce the original disease(IV) Isolating the same germ in many cases
D. The correct sequence is 2,4,3,1. The correct sequence of steps in Koch's postulate is:(I) Obtaining the original germ from infected animals(II) Growing the germ in pure culture(III) Injecting the germ to produce the original disease(IV) Isolating the same germ in many cases

Q34. The disease caused by bacteria is:

A. Small pox
B. Rabies
C. Polio
D. The common cold
E. Tetanus✓

Explanation: Tetanus is a bacterial infection also known as lockjaw. It causes stiffness in various muscles present in different parts of the body. It affects the nervous system. The first affected parts are mostly jaw and neck but it may soon cause muscle contractions in other parts of the body.

Why the other options are wrong

A. It is caused by a virus.
B. The rabies virus causes a rabies infection.
C. Polio virus cause polio.
D. More than 200 viruses can cause a cold, but rhinoviruses are the most common type. Viruses that cause colds can spread from person to person through the air and close personal contact.

Q35. Fungi may be all of the following EXCEPT

A. Heterotrophic
B. Autotrophic✓
C. Saprophytic
D. Decomposers
E. Parasitic

Explanation: Autotrophs are known as producers because they are able to make their own food from raw materials and energy. Examples include plants, algae, and some types of bacteria. Fungi are instead A major group of osmotrophic organisms.

Why the other options are wrong

A. All fungi are heterotrophic, which means that they get the energy they need to live from other organisms.
C. About 100,000 species of fungi are known, and it is estimated that there may be as many as 1.5 million species of fungi in the world. Of these, the vast majority live as “saprophytes.”
D. Fungi are important decomposers, especially in forests. Some kinds of fungi, such as mushrooms, look like plants.
E. Most fungi are saprophytic, which means they feed on decaying organic substances. However, fungi can also be parasitic, where they invade a living host and obtain nourishment, often causing damage to function and structure.

Q36. The octopus, calm and snail are alike in:

A. Having a backbone
B. Having joined legs
C. Being classified as mollusks✓
D. Being Classified as vertebrates
E. Having a three chambered heart

Explanation: ‘Mollusk’ , also spelled mollusc, any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body.

Why the other options are wrong

A. Option A (Having a backbone): Octopuses, clams, and snails are all invertebrates and do not have a backbone. Therefore, option A is incorrect.
B. Option B (Having joined legs): Octopuses do not have legs; they have arms. Clams and snails have muscular foot structures, but they do not have joined legs. Therefore, option B is incorrect.
D. Option D (Being classified as vertebrates): Octopuses, clams, and snails are all classified as invertebrates. Vertebrates are animals with a backbone, which none of these organisms possess. Therefore, option D is incorrect.
E. Option E (Having a three-chambered heart): Octopuses have a closed circulatory system with a three-chambered heart. However, clams and snails have an open circulatory system, and their hearts have different structures. Therefore, option E is incorrect.

Q37. Which of the following lacks vertebrates?

A. The duckbill platypus
B. The turtle
C. The Amphioxus✓
D. The trout
E. The rabbit

Explanation: Amphioxus, although very vertebrate-like, lacks several key vertebrate innovations including neural crest, bone, and an endoskeleton.

Why the other options are wrong

A. Option A (The duckbill platypus) is incorrect because the duckbill platypus is a mammal and belongs to the class of vertebrates.
B. Option B (The turtle) is incorrect because turtles are reptiles and also belong to the class of vertebrates.
D. Option D (The trout) is incorrect because trout is a fish and, like other fish, possesses vertebrates.
E. Option E (The rabbit) is incorrect because rabbits are mammals and have vertebrates.

Q38. The notochord is:

A. Present in adult chordates
B. Present in all echinoderms
C. Present in chordates during embryological developments✓
D. Always a vestigial organ in chordates

Explanation: The notochord is the defining structure of the chordates, and has essential roles in vertebrate development. It serves as a source of midline signals that pattern surrounding tissues and as a major skeletal element of the developing embryo.

Why the other options are wrong

A. Option A (Present in adult chordates): This option is incorrect because the notochord is not present in adult chordates. Instead, it is primarily a developmental structure that forms during embryonic development.
B. Option B (Present in all echinoderms): This option is incorrect because echinoderms, such as starfish and sea urchins, do not possess a notochord. Echinoderms have a different internal support structure known as a water vascular system.
D. Option D (Always a vestigial organ in chordates): This option is incorrect because the notochord is not considered a vestigial organ in chordates. In fact, the notochord plays a crucial role in the early development of chordates, providing support and serving as a foundation for the formation of the vertebral column.

Q39. Classification of organization is based on all the following except:

A. Structure
B. Development
C. Evolutionary relationship
D. Common ancestry
E. Size✓

Explanation: Classification of organisms is not based on size because The sizes of organisms on Earth vary greatly and are not always easy to estimate. Organisms having the same structure/development may vary in sizes.

Why the other options are wrong

A. Structure: The structure of an organization, such as its hierarchy, division of labor, and communication channels, is commonly used for classification purposes. Different organizational structures can reflect different approaches to management and decision-making.
B. Development: The developmental stage of an organization, including its growth, maturity, or decline, can be relevant for classification. It helps understand the organizational life cycle and the challenges and characteristics associated with each stage.
C. Evolutionary relationship: Understanding the evolutionary relationship between organizations can provide insights into their historical development and common ancestry. It can help trace the lineage and development of different organizations and their connections.
D. Common ancestry: The concept of common ancestry is a relevant factor in classifying organizations. It involves identifying shared origins or lineage among organizations, such as subsidiaries of a parent company or organizations that emerged from a common historical or cultural background.

Q40. Which type of mammalian cell does not carry out oxidative phosphorylation?

A. Cardiac muscle cells
B. Liver cells
C. Neurons
D. RBCs✓

Explanation: RBCs have a biconcave shape and it lacks nucleus and mitochondria and hence many metabolic pathways such as oxidative phosphorylation. Instead, RBCs depend on the anaerobic conversion of glucose via pyruvate to lactate.

Why the other options are wrong

A. All three types of cells, namely cardiac muscle cells, liver cells, and neurons, carry out oxidative phosphorylation. They possess mitochondria, which are the cellular organelles responsible for oxidative phosphorylation, the process that generates adenosine triphosphate (ATP) through the utilization of oxygen.
B. All three types of cells, namely cardiac muscle cells, liver cells, and neurons, carry out oxidative phosphorylation. They possess mitochondria, which are the cellular organelles responsible for oxidative phosphorylation, the process that generates adenosine triphosphate (ATP) through the utilization of oxygen.
C. All three types of cells, namely cardiac muscle cells, liver cells, and neurons, carry out oxidative phosphorylation. They possess mitochondria, which are the cellular organelles responsible for oxidative phosphorylation, the process that generates adenosine triphosphate (ATP) through the utilization of oxygen.

Q41. At which site does designation of starches begin:

A. 1✓
B. 2
C. 3
D. 4

Explanation: Starch digestion begins in the mouth with the addition of salivary amylase to food particles. Salivary amylase acts specifically on starch in the food and breaks them down to more simple compounds such as maltose.

Why the other options are wrong

Q42. Structure 4 (Liver) is responsible for:

A. Reduces bile
B. Produces bile✓
C. Secretes bile
D. Secretes bicarbonate
E. Secretes HCl

Explanation: Bile is a digestive fluid produced by the liver and stored in the gallbladder.

Why the other options are wrong

A. The option "reduces bile" is not accurate. The liver does not "reduce" bile. Bile is produced by the liver and stored in the gallbladder. It is then released into the small intestine to aid in the digestion and absorption of fats. The liver does play a role in modifying the composition of bile, but it does not specifically "reduce" it.
C. This option is not correct. The liver is responsible for the production of bile. Bile is synthesized by liver cells known as hepatocytes and is essential for the digestion and absorption of dietary fats. HOWEVER as bile is produced by the liver and then secreted into the small intestine, in the order of events occuring, option B seems correct as bile is first produced and then secreted.
D. The option "secretes bicarbonates" is not accurate. While the liver does play a role in maintaining the acid-base balance in the body, the primary organ responsible for secreting bicarbonates is the pancreas. The pancreas secretes bicarbonate ions into the small intestine to neutralize the acidic chyme coming from the stomach.
E. This option is not accurate. The secretion of hydrochloric acid (HCl) primarily occurs in the stomach, not the liver. The stomach lining contains specialized cells called parietal cells that secrete HCl to aid in the digestion of proteins.

Q43. Which structure is primarily responsible for water absorption during digestion?

A. Liver
B. Pancreas
C. Esophagus
D. Large Intestine✓
E. Trachea

Explanation: The correct answer is the large intestine, which is the primary site for water absorption during digestion. It absorbs water and salts from the material that has not been digested as food, and it compacts waste into feces. The liver, pancreas, esophagus, and trachea have different functions. The liver is involved in bile production and detoxification, the pancreas secretes digestive enzymes and hormones, the esophagus is a food conduit, and the trachea is part of the respiratory system.

Why the other options are wrong

A. The liver primarily produces bile and is involved in detoxification, rather than water absorption.
B. The pancreas produces digestive enzymes and hormones, but does not absorb water.
C. The esophagus serves as a passageway for food from the mouth to the stomach and does not absorb water.
E. The trachea is part of the respiratory system and plays no role in digestion or water absorption.

Q44. Consider the following statements about biological communities.(I) Their members share a common gene pool.(II) The community remains stable even though some physical aspect of the environment may undergo change.(III) They passes predictable kinds of species of predictable proportions.(IV) Interactions between their members are more frequent within the community than between their members and those of neighboring communities.Which two of the above statements apply to all stable biological communities?

A. I band II
B. II and III
C. I band III
D. III and IV✓
E. II and IV

Explanation: A. I is not right since a community involves different populations which may have different gene pool.B. II is also not right since different populations may interact in different ways with each other and disturb the genetic pool and stability.C. III is right and is a fact.D. IV is also right since intra-specific interactions are more common than inter-specific interactions in communities.Hence III and IV are the right options (Option D).

Why the other options are wrong

A. I is not right since a community involves different populations which may have different gene pool.II is also not right since different populations may interact in different ways with each other and disturb the genetic pool and stability.
B. II is also not right since different populations may interact in different ways with each other and disturb the genetic pool and stability.III is right and is a fact. But, in this option only one band shows correct answer.
C. I is not right since a community involves different populations which may have different gene pool.III is right and is a fact. But in this option, only one band is correct.
E. II is also not right since different populations may interact in different ways with each other and disturb the genetic pool and stability.IV is also right since intra-specific interactions are more common than inter-specific interactions in communities. Band 2 showa incorrect answer.

Q45. The diagram summarizes the pathway a glucose breakdownHexose ↓Triose phosphate↓Pyruvate↓Acetyl CoA↓6C compound↓H2O + CO2Which two steps result in a net increase of ATP.

A. 1 and 3
B. 1 and 4
C. 2 and 4✓
D. 2 and 5
E. 3 and 5

Explanation: When 3 carbon triose phosphate is converted into pyruvate 2 molecules of ATP are gained and 2 molecules of ATP are gained in the Krebs cycle.

Why the other options are wrong

A. It is incorrect as 3 carbon triose phosphate is converted into pyruvate 2 molecules of ATP are gained and 2 molecules of ATP are gained in the Krebs cycle.
B. It is incorrect as 3 carbon triose phosphate is converted into pyruvate 2 molecules of ATP are gained and 2 molecules of ATP are gained in the Krebs cycle.
D. It is incorrect as 3 carbon triose phosphate is converted into pyruvate 2 molecules of ATP are gained and 2 molecules of ATP are gained in the Krebs cycle.
E. It is incorrect as 3 carbon triose phosphate is converted into pyruvate 2 molecules of ATP are gained and 2 molecules of ATP are gained in the Krebs cycle.

Q46. Which one of the following enables the mammalian kidney to regulate water reabsorption during states of dehydration?

A. The cells of the tubules detect the osmotic pressure of the blood
B. Water is extracted from the glomerular filtrate in the proximal tubule
C. The kidney produces hyptonic urine
D. Hormones increase the permeability of the collecting ducts✓
E. A low solute concentration is maintained around the collecting ducts

Explanation: Option D is correct.Water excretion by the kidney is regulated by the peptide hormone vasopressin. Vasopressin increases the water permeability of the renal collecting duct cells, allowing more water to be reabsorbed from collecting duct urine to blood.

Why the other options are wrong

A. Option A (The cells of the tubules detect the osmotic pressure of the blood): This statement is incorrect because the cells of the tubules in the kidney do not directly detect the osmotic pressure of the blood. Rather, specialized cells called osmoreceptors in the hypothalamus of the brain detect changes in blood osmolarity and trigger hormonal responses that regulate water reabsorption in the kidney.
B. Option B (Water is extracted from the glomerular filtrate in the proximal tubule): This statement is incorrect because water reabsorption primarily occurs in the more distal parts of the renal tubules, such as the loop of Henle and the collecting ducts. In the proximal tubule, water reabsorption is isotonic, meaning water and solutes are reabsorbed in equal amounts.
C. Option C (The kidney produces hypotonic urine): This statement is incorrect because during states of dehydration, the kidney tends to produce concentrated urine rather than hypotonic urine. Concentrated urine helps conserve water by reducing water loss.
E. Option E (A low solute concentration is maintained around the collecting ducts): This statement is incorrect because the medullary interstitium surrounding the collecting ducts of the kidney is actually maintained at a high solute concentration. This osmotic gradient allows for the reabsorption of water from the collecting ducts and the concentration of urine.

Q47. A drug reduces mitochondrial activity in nephrons of the kidney. Which chemical will be present in increased amounts in the urine?

A. Ammonia
B. Glucose✓
C. Hydrogen bicarbonate
D. Urea

Explanation: This happens because in mitochondria aerobic respiration occurs(breakdown of food in presence of oxygen)The food is glucose.Aerobic respiration:Glucose+O2=CO2 + ATPSo if the mitochondrial activity is reduced then glucose will not be used and will be excreted out through urine.

Why the other options are wrong

A. Option A: Liver disease is the most common cause of high ammonia levels. Decreased blood flow to your liver: If there's a lack of blood flow to your liver, your body can't transfer ammonia to it to be processed.
C. Option C: A bicarbonate level that is higher or lower than normal may mean that the body is having trouble maintaining its acid-base balance, either by failing to remove carbon dioxide through the lungs or the kidneys or perhaps because of an electrolyte imbalance, particularly a deficiency of potassium
D. Option D: High levels of urea in the urine may suggest: too much protein in the diet. Excessive protein breakdown in the body.

Q48. Where, in the nephron, is most glucose reabsorbed?

A. In the ascending loop of henle
B. In the descending loop of henle
C. In the proximal (first) convoluted tubule✓
D. In the distal (second) convoluted tubule

Explanation: Most of the glucose entering the tubular system is reabsorbed along the nephron segments, primarily in the proximal tubule, such that urine is almost free of glucose. This is different in diabetes, where the filtered glucose exceeds the transport capacity of the tubular system for glucose and glucosuria occurs.

Why the other options are wrong

A. Option A (In the ascending loop of Henle): Glucose reabsorption does not occur in the ascending loop of Henle. The ascending loop of Henle is responsible for reabsorbing electrolytes, such as sodium and chloride, but not glucose.
B. Option B (In the descending loop of Henle): Glucose reabsorption does not occur in the descending loop of Henle either. The descending loop of Henle primarily allows for the passive reabsorption of water, not glucose.
D. Option D (In the distal convoluted tubule): Glucose reabsorption does not occur to a significant extent in the distal convoluted tubule. The primary function of the distal convoluted tubule is the fine-tuning of electrolyte balance, primarily sodium and potassium reabsorption and secretion.

Q49. The spinal cord serves as the center of:

A. Subconscious thought
B. Reflex actions✓
C. Habits
D. Tropism

Explanation: It is the processing unit for reflex actions because all nerves from various parts of the body meet at the spinal cord before reaching the brain.

Why the other options are wrong

A. Option A (Subconscious thought): The spinal cord is not involved in conscious or subconscious thought processes. Thinking and cognitive functions are primarily associated with the brain, not the spinal cord.
C. Option C (Habits): The formation and control of habits are complex processes involving various brain regions and neural circuits. The spinal cord does not serve as the center for habit formation or control.
D. Option D (Tropism): Tropism refers to the growth or movement of an organism in response to external stimuli. The spinal cord is not involved in tropism as it primarily functions in transmitting sensory and motor signals rather than directing growth or movement responses.

Q50. The most abundant substance in protoplasm is:

A. Protein
B. Fat
C. Carbohydrate
D. Water✓
E. Minerals

Explanation: Protoplasm is a mixture of small molecules such as ions, monosaccharides, amino acids, and macromolecules such as proteins, polysaccharides, lipids, etc.On the average protoplasm contains 84 percent water. Most of the water is present in free unbounded form and provides a medium for metabolic reactions occurring in a cell.

Why the other options are wrong

A. Option A (Protein): While proteins are important components of protoplasm, they are not the most abundant substance. Protoplasm consists mainly of water and various organic and inorganic compounds.
B. Option B (Fat): Fats are present in protoplasm but are not the most abundant substance.
C. Option C (Carbohydrate): Carbohydrates are important for energy storage and utilization but are not the most abundant substance in protoplasm.
E. Option E (Minerals): Minerals are essential for various cellular functions, but they are not the most abundant substance in protoplasm.

Q51. The placenta releases all of the following hormones EXCEPT:

A. Progesterone
B. LH (Luteinizing Hormone)✓
C. HCG (Human Chorionic Gonadotropin)
D. Estrogen
E. Minerals

Explanation: The correct answer is LH (Luteinizing Hormone). LH is produced by the pituitary gland and is not released by the placenta. It plays a crucial role in the menstrual cycle and ovulation process. The other hormones listed—progesterone, HCG, and estrogen—are produced by the placenta during pregnancy to support the developing fetus and maintain the pregnancy. While the placenta does not release minerals directly, it is involved in nutrient transfer from the mother to the fetus.

Why the other options are wrong

A. This is incorrect. The placenta synthesizes progesterone, which is crucial for maintaining the uterine lining and supporting pregnancy throughout its term.
C. This is incorrect. The placenta produces HCG, which is important for maintaining pregnancy and is commonly used in pregnancy tests.
D. This is incorrect. Estrogen is produced by the placenta and plays a significant role in pregnancy, including the development of the fetus and preparation of the mother's body for childbirth.
E. This is incorrect. While the placenta does not directly release minerals, it does facilitate the transfer of essential nutrients, including minerals, from the mother to the fetus.

Q52. All of the following organs produce hormones involved in the reproductive cycle except the:

A. Testes
B. Pituitary Gland
C. Pancreas✓
D. Ovary
E. Uterus

Explanation: The pancreas is primarily involved in metabolic functions, specifically the regulation of blood sugar levels through hormones like insulin and glucagon. It does not play a role in the reproductive cycle, unlike the testes, pituitary gland, ovaries, and uterus, all of which produce hormones critical to reproductive processes. Thus, the pancreas does not contribute to hormone production for reproduction, making it the correct answer.

Why the other options are wrong

A. The testes produce testosterone, a hormone essential for male reproductive functions.
B. The pituitary gland secretes hormones such as FSH (Follicle Stimulating Hormone) and LH (Luteinizing Hormone), which play critical roles in regulating the reproductive cycle.
D. The ovaries produce estrogen and progesterone, both of which are crucial for female reproductive processes.
E. During pregnancy, the uterus can produce hormones, such as estrogen, that support the reproductive process.

Q53. In human female FSH regulates the concentration of:

A. A: Control
B. B: Estrogen✓
C. C: Cortisol
D. D: Aldosterone
E. E: None of the above

Explanation: Follicle stimulating hormone (FSH) is crucial in managing the female reproductive system. It is produced by the pituitary gland and influences the menstrual cycle by promoting the growth of ovarian follicles. FSH specifically stimulates the granulosa cells in these follicles to secrete estrogen, which is essential for ovulation and overall reproductive health. This distinguishes estrogen from other hormones like cortisol and aldosterone, which are regulated by different mechanisms and serve different purposes in the body.

Why the other options are wrong

A. FSH is not involved in regulating control substances in the body. Its primary role is related to reproductive hormones.
C. Cortisol is a stress hormone regulated by the adrenal glands, not by FSH, which focuses on reproductive functions.
D. Aldosterone is involved in regulating blood pressure and electrolytes, not influenced by FSH, which is concerned with reproductive health.
E. Estrogen is indeed regulated by FSH, making this option incorrect.

Q54. Reduction division occur during the process of:

A. Reduction
B. Differentiation
C. Fertilization
D. Meiosis✓
E. Parthenogenesis

Explanation: The first cell division in meiosis, the process by which germ cells are formed. In reduction division, the chromosome number is reduced from diploid (46 chromosomes) to haploid (23 chromosomes). Also known as first meiotic division and first meiosis.Each daughter chromosome is pulled along by its centromere. The two sister chromatids of each chromosome are pulled apart by the spindle and dragged by their kinetochores toward opposite poles of the cell. Hence there is a reduction in the number of chromosomes to half.

Why the other options are wrong

A. Option A (Reduction): Reduction division does occur during the process of meiosis, but it is not the specific process itself. Reduction division refers to the reduction in chromosome number that happens during meiosis.
B. Option B (Differentiation): Differentiation refers to the process by which cells become specialized and take on specific functions. It does not involve reduction division.
C. Option C (Fertilization): Fertilization is the union of gametes to form a zygote. While it involves the combination of genetic material, it does not directly involve reduction division.
E. Option E (Parthenogenesis): Parthenogenesis is a form of reproduction in which offspring develop from unfertilized eggs. It does not involve reduction division.

Q55. The muscles attached to the bones are

A. Voluntary and smooth
B. Involuntary and smooth
C. Voluntary and striated✓
D. Involuntary and striated
E. Smooth and striated

Explanation: Voluntary muscles are under conscious control, allowing us to move our bodies intentionally. Striated muscles have a striped appearance under a microscope due to the organization of their contractile proteins, giving them the name "striated." These muscles are also known as skeletal muscles and are responsible for body movements.

Why the other options are wrong

A. Muscles attached to bones are voluntary but not smooth.
B. Muscles attached to bones are neither smooth nor involuntary.
D. Muscles attached to bones are striated but not involuntary.
E. Muscles attached to bones are striated but not smooth.

Q56. Which of the following statement regarding the periosteum is INCORRECT:

A. The periosteum serves as the site of attachment of bone to muscle
B. Cells of the periosteum differentiate into osteoblasts.✓
C. The periosteum is a fibrous sheath that surrounds long bones
D. None of the above

Explanation: Your periosteum helps your bones grow and develop.Osteoblasts originate from immature mesenchymal stem cells, which can also differentiate and give rise to chondrocytes. Mesenchymal stem cells undergo several transcription steps to form mature osteoblast cells.

Why the other options are wrong

A. Option A is incorrect because the periosteum does not serve as the direct attachment site for muscles to bone. Tendons and ligaments are responsible for connecting muscles and bones.
C. Option C is incorrect because the periosteum is a fibrous connective tissue layer that covers the outer surface of bones, including long bones.
D. Option D is incorrect because options A and C are incorrect.

Q57. The most correct statement about muscle contraction is:

A. Actin itself moves to shorten the muscle
B. Cross bridges formed between myofibril molecules are made of G-actin
C. Contraction of myosin molecules directly causes muscle contraction
D. Ca²⁺ is necessary for the binding of cross bridges✓

Explanation: Calcium ions (Ca²⁺) are essential for muscle contraction. When a muscle is stimulated to contract, calcium ions are released from the sarcoplasmic reticulum. These ions bind to troponin, a regulatory protein on the actin filaments. This binding causes a change in the shape of the troponin-tropomyosin complex, exposing binding sites on the actin for myosin heads. This exposure allows myosin to form cross bridges with actin, initiating the contractile process.Option A is incorrect because the actin filaments do not independently move to shorten the muscle; they are pulled by myosin heads. Option B is incorrect because cross bridges are not formed from G-actin but involve myosin heads binding to actin. Option C is incorrect because it is the action of myosin heads, not the contraction of myosin molecules, that causes muscle contraction.

Why the other options are wrong

A. Option A is incorrect because the actin filaments do not move independently to shorten the muscle. Instead, muscle contraction occurs through the sliding filament mechanism, where myosin heads pull actin filaments towards the center of the sarcomere, shortening the muscle.
B. Option B is incorrect because cross bridges are formed between myosin heads and actin filaments, not between separate myofibril molecules. Myofibrils are composed of repeating units of sarcomeres, which include both actin and myosin.
C. Option C is incorrect because muscle contraction is not caused by a contraction of myosin molecules themselves. Instead, myosin heads bind to actin and perform a power stroke, pulling the actin filaments towards the center of the sarcomere.

Q58. The absorption and use of calcium are regulated by:

A. Parathormone✓
B. Adrenaline
C. Thyroxin
D. Thiamin
E. Prolactin

Explanation: Circulating parathyroid hormone targets the distal convoluted tubule and collecting duct, directly increasing calcium reabsorption.

Why the other options are wrong

B. Option B: Adrenaline, also known as epinephrine, is not directly involved in the regulation of calcium absorption or use in the body. Its primary functions are related to the fight-or-flight response, such as increasing heart rate and blood pressure.
C. Option C: Thyroxin, or thyroxine, is a hormone produced by the thyroid gland that regulates metabolism. While thyroid hormones play a role in overall metabolic regulation, they are not directly involved in the regulation of calcium absorption or use.
D. Option D: Thiamin, also known as vitamin B1, is an essential nutrient involved in energy metabolism. However, it does not directly regulate calcium absorption or use in the body.
E. Option E: Prolactin is a hormone primarily associated with lactation and milk production in females. It does not have a direct role in the regulation of calcium absorption or use.

Q59. On a very cold day, a man waits for over an hour at the bus stop. Which of the following structures helps his body set and maintain a normal temperature?

A. Hypothalamus✓
B. Kidneys
C. Posterior pituitary
D. Brainstem

Explanation: On a cold day, the body must maintain a stable core temperature to function properly. The hypothalamus is crucial for this task as it senses changes in body temperature and triggers responses like shivering and vasoconstriction to conserve heat. This makes the hypothalamus the correct answer. In contrast, the kidneys focus on fluid balance, the posterior pituitary on hormone release, and the brainstem on other automatic functions, none of which directly involve temperature regulation.

Why the other options are wrong

B. The kidneys primarily manage fluid and electrolyte balance and excrete waste products. They do not have a direct role in regulating body temperature, which is controlled by the hypothalamus.
C. The posterior pituitary gland releases hormones such as oxytocin and antidiuretic hormone (ADH), which influence water balance and reproductive processes, but it does not regulate body temperature.
D. The brainstem manages essential automatic functions like breathing and heart rate. While it is vital for survival, it is not specifically responsible for maintaining body temperature; that role is primarily held by the hypothalamus.

Q60. Which hormone triggers your body to retain NaCl, especially during periods of excessive heat?

A. Aldosterone✓
B. Progesterone
C. ACTH
D. Epinephrine
E. Testosterone

Explanation: Aldosterone signals certain organs, like your kidneys and colon, to increase the amount of sodium they send into your bloodstream or the amount of potassium released in your urine. Aldosterone's effect on sodium increase causes your body to retain water in your blood, which increases blood volume.

Why the other options are wrong

B. Option B (Progesterone) is incorrect because progesterone is not involved in the regulation of sodium chloride (NaCl) retention. Progesterone is a hormone primarily associated with the female reproductive system and plays a role in menstrual cycle regulation and pregnancy.
C. Option C (ACTH - Adrenocorticotropic hormone) is incorrect because ACTH is primarily involved in stimulating the production and release of cortisol from the adrenal glands. It does not directly regulate sodium chloride retention.
D. Option D (Epinephrine) is incorrect because epinephrine, also known as adrenaline, is primarily involved in the body's response to stress or emergency situations. While it can affect various physiological processes, it does not specifically trigger sodium chloride retention.
E. Option E (Testosterone) is incorrect because testosterone is a male sex hormone that is primarily involved in the development of male reproductive tissues and secondary sexual characteristics. It does not have a direct role in sodium chloride retention.

Q61. Which of the following is true regarding passive and active immunity?

A. Active immunity requires weeks to build, where as passive immunity is acquired immediately✓
B. Active immunity is short lived, whereas passive immunity is long lived
C. Active immunity may be acquired during pregnancy through placenta
D. Passive immunity may be acquired through vaccination

Explanation: Option A is the correct answer.Option B: Passive immunity lasts only for a few weeks or months. Only active immunity is long-lasting.Option C: During the last 3 months of pregnancy, antibodies from mothers are passed to their unborn babies through the placenta. This type of immunity is called passive immunity because the baby has been given antibodies rather than making them itself.Option D: Vaccines provide active immunity to disease.

Why the other options are wrong

B. Option B: Passive immunity lasts only for a few weeks or months. Only active immunity is long-lasting.
C. Option C: During the last 3 months of pregnancy, antibodies from mothers are passed to their unborn babies through the placenta. This type of immunity is called passive immunity because the baby has been given antibodies rather than making them itself.
D. Option D: Vaccines provide active immunity to disease.

Q62. Which of the following is NOT an example of a non –specific defense mechanism?

A. Skin provides a physical barrier against invasion
B. Macrophages engulf and destroy foreign particles
C. An inflammatory response to physical damage
D. Cytotoxic T cells destroy foreign antigens✓

Explanation: The cytotoxic T cells destroy foreign antigens is a specific defense mechanismSpecific defense : (sometimes called adaptive immunity) recognizes and coordinates attacks against specific pathogens. The system can also remember pathogens and produce a powerful response the next time a pathogen enters the body.The cytotoxic T cells bind to the infected cells and secrete cytotoxins that induce apoptosis (cell suicide) in the infected cell and perforins that cause perforations in the infected cells. Both of these mechanisms destroy the pathogen in the infected body cell.

Why the other options are wrong

A. Option A is incorrect because the skin provides a non-specific defense mechanism known as a physical barrier. It acts as the body's first line of defense, preventing the entry of pathogens and foreign substances.
B. Option B is incorrect because macrophages are part of the innate immune system and represent a non-specific defense mechanism. They engulf and destroy foreign particles, pathogens, and cellular debris through a process called phagocytosis.
C. Option C is incorrect because an inflammatory response is also a non-specific defense mechanism. It is triggered by physical damage, infection, or injury and involves various processes, such as increased blood flow, swelling, and recruitment of immune cells, to eliminate pathogens and promote tissue repair.

Q63. When B –cells are presented with antigen they differentiate into:

A. T cells
B. Helper T cells
C. Plasma cells✓
D. Bursa cells

Explanation: In the latter, typically activated B cells acquire cognate signals from T helper cells in the germinal center of lymphoid follicles to differentiate into plasma cells (PCs), which generate protective antibodies.

Why the other options are wrong

A. Option A (T cells) is incorrect because B-cells do not differentiate into T cells. B-cells and T cells are distinct types of lymphocytes that play different roles in the immune response.
B. Option B (Helper T cells) is incorrect because B-cells do not differentiate into helper T cells. Helper T cells are a subset of T cells that assist in activating B-cells and other immune cells during the immune response.
D. Option D (Bursa cells) is incorrect because bursa cells are not a known cell type involved in the immune response. The bursa of Fabricius is a specialized organ found in birds that plays a role in B-cell development, but it does not refer to a specific cell type.

Q64. During which of the following processes ATP is produced? (I) Photosynthesis(II) Aerobic respiration(III) Anaerobic respiration

A. I only
B. II only
C. I and II only
D. I, II and III only✓

Explanation: ATP is produced during photosynthesis as well as aerobic and anaerobic respiration.

Why the other options are wrong

A. Option A (I only) is incorrect because ATP is produced not only during photosynthesis but also during cellular respiration.
B. Option B (II only) is incorrect because ATP is produced not only during aerobic respiration but also during anaerobic respiration.
C. Option C (I and II only) is incorrect because ATP is also produced during anaerobic respiration, not just during photosynthesis and aerobic respiration.

Q65. Structures that conduct materials throughout a plant are called?

A. Lenticels
B. Meristem
C. Fibrovascular bundles✓
D. Cambium
E. Epidermis

Explanation: The vascular cambium are unspecialised meristematic tissues that are found in between the primary xylem and primary phloem. Since it is a meristematic tissue, it gives rise to secondary xylem and secondary phloem.

Why the other options are wrong

A. Option A (Lenticels) is incorrect because lenticels are small openings or pores in the bark of woody plants that allow for gas exchange. They are not structures that conduct materials throughout a plant.
B. Option B (Meristem) is incorrect because meristem refers to the tissue in plants that contains undifferentiated cells and is responsible for growth and development. While meristem plays a role in the production of new cells and tissues, it is not directly involved in the conduction of materials.
D. Option D (Cambium) is incorrect because cambium is a tissue layer in plants that is responsible for secondary growth, leading to the production of new vascular tissue (xylem and phloem). While cambium is involved in the development of conducting tissues, it is not the structure itself that conducts materials throughout the plant.
E. Option E (Epidermis) is incorrect because the epidermis is the outermost layer of cells in plants that serves as a protective barrier. While the epidermis covers the surface of the plant, it does not have a direct role in conducting materials.

Q66. Green plants carry on respiration

A. Only during the day
B. Only at night
C. During both day and night✓
D. Only when photosynthesis is going on

Explanation: Respiration is the process by which cells generate energy from glucose and oxygen, and it is a continuous metabolic activity necessary for the plant's survival. While photosynthesis primarily occurs during the day when there is light available, respiration occurs 24/7 because plants need energy both for their daytime activities and to support basic functions like growth and maintenance during the night when there is no sunlight for photosynthesis. Therefore, plants respire both during the day and at night to maintain their life processes.

Why the other options are wrong

A. Plants respire during the day and night, as respiration is essential for their survival. It provides energy for various cellular processes, including growth and maintenance.
B. While respiration may be more noticeable at night due to the absence of photosynthesis, plants still respire during the day to maintain their metabolic functions.
D. Respiration is not limited to times when photosynthesis is occurring. It happens around the clock because plants need a constant supply of energy and to support metabolic processes, even when photosynthesis is not active.

Q67. Photophosphorylation during photosynthesis results in the formation of:

A. ATP✓
B. NAD
C. FAD
D. ADP

Explanation: Photophosphorylation is the process of utilizing light energy from photosynthesis to convert ADP to ATP.

Why the other options are wrong

B. NAD is involved in electron transport and redox reactions.
C. FAD is involved in electron transport and redox reactions.
D. ADP (Option D) is the precursor to ATP and is converted to ATP during photophosphorylation.

Q68. Which of the following has evolved mainly as a result of artificial selection?

A. Darker coloring of prepared moth near industrial areas
B. Increased production of antibiotics by the fungus penicillium species✓
C. Increased resistance of houseflies to the insecticide DDT
D. Increased resistance of lichens to the heavy metals on tree bark around mine workings

Explanation: Artificial selection is an evolutionary process in which humans consciously select for or against particular features in organisms. Increased production of antibiotics by the fungus penicillium species has evolved as a result of artificial selection.

Why the other options are wrong

A. Option A, darker coloring of prepared moths near industrial areas, is incorrect because it refers to the famous example of natural selection (not artificial selection) known as industrial melanism, where darker moths had a survival advantage in polluted environments.
C. Option C, increased resistance of houseflies to the insecticide DDT, is incorrect because it is an example of natural selection. Houseflies developed resistance to DDT over time due to the survival and reproduction of individuals with genes that conferred resistance.
D. Option D, increased resistance of lichens to heavy metals on tree bark around mine workings, is incorrect because it is also an example of natural selection. Lichens that are better adapted to tolerate heavy metal pollution in their environment survive and reproduce, leading to an increase in resistant populations.

Q69. The technique of DNA fingerprinting has been used to identify people in crime, accidents, and family relationships. To analyze the DNA of members of the same family, it is necessary to examine samples of their tissues for:

A. Similarities in the nucleotide uracil
B. Similarities in the deoxyribose sugar
C. Similarities in nucleotide base pairs✓
D. RNA differences

Explanation: Similarities in the nucleotide base pairs is the correct answer. Uracil is not related to DNA and is a nucleotide of RNA.The structure of deoxyribose sugar is the same in all.

Why the other options are wrong

A. Uracil is the base pair present in RNA and not DNA.
B. Deoxyribose is same in all nucleotides,
D. Option D is same as option C.

Q70. Five stages in the production of human insulin by genetic engineering techniques are given1. DNA cut with restriction enzymes2. DNA copy made using reverse transcriptase3. Messenger RNA extracted from cells4. Plasmid RNA joined to donor DNA using a ligase enzyme5. Recombinant plasmid inserted into bacterial cellWhich sequence is correct?First ------ Last

A. 1->3->2->5->4
B. 1->3->4->2->5
C. 2->1->3->2->5
D. 3->2->1->4->5✓

Explanation: First step is extraction of mRNA, in second step same mRNA is reversed to make a copy of DNA, in step 3 restriction enzyme is used to cut DNA, is step 4 ligase enzyme is to join donor DNA to plasmid RNA, in step 5 recombinant plasmid is inserted into the cell.

Why the other options are wrong

A. Option A is incorrect because step 2 (DNA copy made using reverse transcriptase) should occur after step 3 (messenger RNA extracted from cells).
B. This option is incorrect because first step starts from step 3. The stages in the production of human insulin by genetic engineering techniques are as follows:1. Messenger RNA (mRNA) is extracted from cells.2.The mRNA is converted into complementary DNA (cDNA) using reverse transcriptase.3. The cDNA is cut using restriction enzymes.4. The cut cDNA is joined to a plasmid DNA using ligase enzyme to create a recombinant plasmid.5. The recombinant plasmid is inserted into a bacterial cell.
C. This option is incorrect because first step starts from step 3.The stages in the production of human insulin by genetic engineering techniques are as follows:1. Messenger RNA (mRNA) is extracted from cells.2.The mRNA is converted into complementary DNA (cDNA) using reverse transcriptase.3. The cDNA is cut using restriction enzymes.4. The cut cDNA is joined to a plasmid DNA using ligase enzyme to create a recombinant plasmid.5. The recombinant plasmid is inserted into a bacterial cell.

Q71. All of the following statements about tropical rain forests are true EXCEPT:

A. They regulate the global climate of entire planet
B. Through photosynthesis they give off great quantities of carbon dioxide✓
C. They contribute perhaps 50% of the rainfall in the amazon area
D. They contain countless thousands of species of plants and animals
E. Their soil is comparatively infertile

Explanation: Tropical rainforests encompass approximately 1.2 billion hectares (3 billion acres) of vegetation and are sometimes described as the Earth's thermostat. Rainforests produce about 20% of our oxygen and store a huge amount of carbon dioxide, drastically reducing the impact of greenhouse gas emissions.

Why the other options are wrong

A. Option A is incorrect because while tropical rainforests play a significant role in local and regional climate regulation, they do not regulate the global climate of the entire planet.
C. Option C is incorrect because tropical rainforests do contribute a significant amount of rainfall to their respective regions, but the statement exaggerates their contribution to the rainfall in the Amazon area.
D. Option D is incorrect because tropical rainforests are known for their high biodiversity and do indeed contain countless thousands of species of plants and animals.
E. Option E is incorrect because tropical rainforest soils are often nutrient-rich and diverse, not infertile. The high biodiversity in these ecosystems contributes to the cycling of nutrients and the overall fertility of the soil.

Q72. What are edaphic factors in the environment concerned with:

A. Animals
B. The soil✓
C. Climate
D. Wave action
E. Fire

Explanation: These edaphic factors are related to the structure and composition of the soil. It includes the physical, chemical, and biological properties of soil. The soil composition, organic matter content, soil moisture, humidity, and microorganisms all constitute edaphic factors.

Why the other options are wrong

A. Option A, animals, is incorrect because edaphic factors specifically pertain to the soil and its characteristics.
C. Option C, climate, is incorrect because climate refers to the long-term weather patterns in an area and is not directly related to the soil.
D. Option D, wave action, is incorrect because edaphic factors focus on soil properties and are not related to the movement of water or waves.
E. Option E, fire, is incorrect because edaphic factors are concerned with soil characteristics and not directly related to fire occurrences.

Q73. A cross in which three fourths of the offspring appear dominant is:

A. Tt x TT
B. TT x tt
C. Tt x tt
D. Tt xTt✓
E. TT x TT

Explanation: Option D is the correct answer.Results are TT, Tt, Tt, tt.3/4 is dominant, 1/4 is recessive (tt).

Why the other options are wrong

A. If one parent is heterozygous (Tt) and the other is homozygous dominant (TT)All offspring are dominant in appearance.Phenotypic ratio = 100% dominant (4:0) Conclusion: Incorrect — not 3/4 dominant.
B. Gametes from TT are all T, and from tt are all t. So all offspring are Tt (heterozygous).All show the dominant trait.Phenotypic ratio = 100% dominant (4:0) Conclusion: Incorrect — not 3/4 dominant.
C. Gametes from Tt are T and t, from tt are t only.Phenotypic ratio = 1:1 (50% dominant, 50% recessive) Conclusion: Incorrect — only half are dominant.
E. Both parents are homozygous dominant, so all offspring will be TT (dominant).Phenotypic ratio = 100% dominant (4:0) Conclusion: Incorrect — all dominant, not 3/4.

Q74. Which of the following is the combination of bases that cannot be present in DNA is:

A. AUCG✓
B. ATCG
C. ATTA
D. CGTA
E. GCAT

Explanation: DNA is composed of 4 base pairs 1) Adinine, 2)Thymine 3)Guanine 4)Cytosine. Uracil is present in RNA which differentiate RNA and DNA.

Why the other options are wrong

B. DNA is composed of 4 base pairs 1) Adenine, 2)Thymine 3)Guanine 4)Cytosine.
C. DNA is composed of 4 base pairs 1) Adenine, 2)Thymine 3)Guanine 4)Cytosine. These bases are present in DNA in specific gene.
D. DNA is composed of 4 base pairs 1) Adenine, 2)Thymine 3)Guanine 4)Cytosine. These bases are present in DNA in specific gene.
E. DNA is composed of 4 base pairs 1) Adenine, 2)Thymine 3)Guanine 4)Cytosine. These bases are present in DNA in specific gene.

Q75. Plants and animals cells are alike in processing:

A. Chlorophyll
B. Chloroplast
C. Cell wall
D. Cellulose
E. Cell membrane✓

Explanation: Cell membrane is present in both plant and animal cells. Rest are all present in plant cells and not animal cells.

Why the other options are wrong

A. Chlorophyll is located in a plant's chloroplasts, which are tiny structures in a plant's cells. This is where photosynthesis takes place.
B. Plant cells have certain distinguishing features, including chloroplasts, cell walls, and intracellular vacuoles. Photosynthesis takes place in chloroplasts .
C. Plant cells are surrounded by a tough extracellular matrix in the form of a cell wall, which is responsible for many of the unique features of a plant's life style.
D. Cellulose is found in the cell walls of plants and their organs such as fruits, leaves, and vegetables.

Q76. Which of the following choices correctly shows structures which are found in eukaryotic cells? (√= present , x= absent)

A. A
B. B
C. C
D. D
E. E✓

Explanation: Eukaryotic cells have all three things.

Why the other options are wrong

A. Eukaryotic cell contains nuclear membrane, mitochondria and ribosomes.
B. This option is incorrect as these cells have mitochondria.Eukaryotic cells have all three things.
C. This option is incorrect as these cells have nuclear membrane.Eukaryotic cells have all three things.
D. This option is incorrect as these cells have both nuclear membrane and ribosomes.Eukaryotic cells have all three things.

Q77. Which one of the following types of bond is principally concerned in maintaining the alpha helix shape of secondary protein structure?

A. Disulphide bonds
B. Peptide bonds
C. Ester bonds
D. Phosphate bonds
E. Hydrogen bonds✓

Explanation: α-helices are formed and maintained by backbone interactions parallel to the primary axis of the helix. These interactions are hydrogen bonds between the carbonyl oxygen and amino nitrogen of the ith and i + 4th amino acids.

Why the other options are wrong

A. Option A, disulfide bonds, is incorrect because disulfide bonds are involved in maintaining the tertiary structure of proteins, not the alpha helix shape of secondary protein structure.
B. Option B, peptide bonds, is incorrect because peptide bonds are the bonds that link amino acids together to form the polypeptide chain, but they are not directly involved in maintaining the alpha helix structure.
C. Option C, ester bonds, is incorrect because ester bonds are not relevant to the structure or stability of proteins.
D. Option D, phosphate bonds, is incorrect because phosphate bonds are primarily involved in the structure and function of nucleic acids (DNA and RNA) rather than protein structure.

Q78. Which class of molecule is the major component of cell membrane?

A. Phospholipid✓
B. Cellulose
C. Wax
D. Triglyceride

Explanation: The fundamental building blocks of all cell membranes are phospholipids, which are amphipathic molecules, consisting of two hydrophobic fatty acid chains linked to a phosphate-containing hydrophilic head group.

Why the other options are wrong

B. Option B, cellulose, is incorrect because cellulose is a polysaccharide found in the cell walls of plants, not the major component of cell membranes.
C. Option C, wax, is incorrect because wax is a hydrophobic substance that is not a major component of cell membranes.
D. Option D, triglyceride, is incorrect because triglycerides are primarily used for energy storage and are not the major component of cell membranes.

Q79. Energy can be made available to the body in the following ways:(I) Conversion of surplus amino acids and glycerol to blood glucose and the mobilization of fat deposits which pass to the tissues for oxidation.(II) Breakdown of liver and muscle glycogen to form glucose.(III)Breakdown of tissue proteins to release amino acids which are then converted into glucose.In which order does the body draw on potential energy when it is being starved of food?

A. I , II and III
B. I , III and II
C. II , I and III✓
D. II , III and I

Explanation: Option C (II, I, and III) is correct because the conversion of surplus amino acids and glycerol to blood glucose and the mobilization of fat deposits (I) occurs after the breakdown of liver and muscle glycogen (II). Therefore, the correct order should be II, I and III.

Why the other options are wrong

A. The first thing to do would be breakdown of liver and muscle glycogen to glucose. First process would then by followed by remove extra amino acids and glycerol to glucose since they are surplus After that, tissue proteins will release amino acids and get converted into glucose. Hence option A is incorrect.
B. Option B (I, III, and II) is incorrect because the breakdown of tissue proteins (III) occurs before the breakdown of liver and muscle glycogen (II) when the body is being starved of food. Therefore, the correct order should be II,I,III.
D. Option D (II, III, and I) is incorrect because the breakdown of tissue proteins (III) occurs before the conversion of surplus amino acids and glycerol to blood glucose and the mobilization of fat deposits (I). Therefore, the correct order should be II,I, III.

Q80. The autonomic nervous system controls all of the following activities EXCEPT:

A. Secretion of digestive juices
B. Peristalsis
C. Sweating
D. Thought✓

Explanation: The autonomic nervous system manages body processes you don't think about. Those processes include heartbeat, blood pressure, digestion and more.

Why the other options are wrong

A. Option A, secretion of digestive juices, is incorrect because the autonomic nervous system does control the secretion of digestive juices. It regulates the activity of glands involved in digestion.
B. Option B, peristalsis, is incorrect because the autonomic nervous system controls peristalsis, which is the rhythmic contractions of smooth muscles that propel food through the digestive tract.
C. Option C, sweating, is incorrect because the autonomic nervous system controls sweating. It regulates the activity of sweat glands in response to temperature regulation or emotional stress.

Q81. The nucleus contains all of the following structures except:

A. Mitochondria✓
B. Chromatin
C. Genes
D. Nucleolus
E. Nuclear membrane

Explanation: Nucleus contains nuclear envelope, nuclear lamina, nucleolus, chromosomes, nucleoplasm. Numerous Mitochondria are present in cell but not in nucleus.

Why the other options are wrong

B. Option B, chromatin, is incorrect because chromatin is a complex of DNA, RNA, and proteins that make up the genetic material within the nucleus.
C. Option C, genes, is incorrect because genes are segments of DNA that encode for specific traits and are located within the nucleus.
D. Option D, nucleolus, is incorrect because the nucleolus is a structure within the nucleus that is involved in the production of ribosomes.
E. Option E, nuclear membrane, is incorrect because the nuclear membrane (also known as the nuclear envelope) is a double membrane that surrounds and encloses the nucleus, separating it from the cytoplasm.

Q82. Which of the following choices INCORRECTLY pairs a digestive enzyme with its secretion?

A. Pancreatic amylase -> pancreas
B. Aminopeptidase -> stomach✓
C. Enterokinase -> intestinal glands
D. Maltase -> intestinal glands

Explanation: Aminopeptidases catalyze the cleavage of amino acids from the amino terminus of protein or peptide substrates.It is produced and secreted by glands of the small intestine.

Why the other options are wrong

A. Option A, pancreatic amylase -> pancreas, is incorrect because pancreatic amylase is indeed secreted by the pancreas.
C. Option C, enterokinase -> intestinal glands, is incorrect because enterokinase is an enzyme that is produced by the duodenal glands, not the intestinal glands.
D. Option D, maltase -> intestinal glands, is incorrect because maltase is an enzyme that is produced by the brush border cells of the small intestine, not the intestinal glands.

Q83. Macromolecules are of types:

A. 3
B. 4✓
C. 5
D. 6

Explanation: Macro molecules are of 4 types.1. Proteins2. Lipids3. Carbohydrates 4. Nucleic acids.

Why the other options are wrong

A. Macromolecules are of 4 types.
C. Macromolecules are of 4 types.
D. Macromolecules are of 4 types.

Q84. The long chains of amino acids are called:

A. Oils
B. Polypeptide✓
C. Monopeptide
D. Protein

Explanation: The primary structure of proteins is made up of long-chain amino acids known as the polypeptide chain.

Why the other options are wrong

A. Any of a large class of substances typically unctuous, viscous, combustible, liquid at ordinary temperatures, and soluble in ether or alcohol but not in water.
C. Any peptide containing a single amino acid (combined with some other entity) .
D. Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues.

Q85. Select the correct general formula for carbohydrates:

A. C2nHnO2n
B. Cn(H2O)2n
C. Cn(H2O)n✓
D. CnH3nO2n
E. Hn(C2O)n

Explanation: The term carbohydrate means "hydrate of carbon." Many common carbohydrates have the empirical formula CH2O, which can be generalized to Cn(H2O)n. This formula shows that the ratio of hydrogen to oxygen atoms is 2:1, the same as in water.

Why the other options are wrong

A. The number of hydrogen atoms are usually double the number of carbon atoms. This option suggests opposite of it.
B. This option incorrectly assumes the number of oxygen atoms to be greater than than number of carbon atoms.
D. This formula shows the number of hydrogen atoms to be three times the number of carbon atoms while hydrogen atoms are usually double the number of carbon atoms. Moreover, the number of oxygen atoms represented is incorrect too.
E. This formula resembles hydrocarbons and lacks the correct oxygen to carbon ratio for carbohydrates.

Q86. Lipids are generally defined in terms of:

A. Solubility✓
B. Structure
C. Molarity
D. All of the above

Explanation: Lipids are defined by Solubility and Intermolecular Forces. lipids are a class of naturally occurring molecules that are soluble in nonpolar organic solvents, and are not soluble in water.

Why the other options are wrong

B. Option B, structure, is incorrect because lipids are not defined solely in terms of their structure. While lipids do share certain structural characteristics, such as being hydrophobic and composed of fatty acids, their definition goes beyond just their structural features.
C. Option C, molarity, is incorrect because lipids are not defined based on their molarity. Molarity refers to the concentration of a substance in a solution, which is not relevant to the definition of lipids.
D. Option D, all of the above, is incorrect because options B and C are incorrect, as explained above. Lipids are primarily defined in terms of their solubility, as they are hydrophobic and insoluble in water.

Q87. As a result of increased CO2 in the atmosphere, oceans will become more:

A. Alkaline
B. Acidic✓
C. Saline
D. Cooler

Explanation: Because of human-driven increased levels of carbon dioxide in the atmosphere, there is more CO2 dissolving into the ocean. The ocean's average pH is now around 8.1 , which is basic (or alkaline), but as the ocean continues to absorb more CO2, the pH decreases and the ocean becomes more acidic.

Why the other options are wrong

A. Option A (Alkaline) is incorrect because increased carbon dioxide (CO2) in the atmosphere leads to ocean acidification, not alkalinity. When CO2 dissolves in seawater, it forms carbonic acid, which leads to a decrease in pH and an increase in acidity.
C. Option C (Saline) is incorrect because increased CO2 levels in the atmosphere do not directly impact the salinity of the oceans. Salinity in the oceans is primarily influenced by factors such as evaporation, precipitation, and freshwater input from rivers.
D. Option D (Cooler) is incorrect because increased CO2 in the atmosphere is associated with global warming and leads to an increase in the average temperature of the Earth, including the oceans. The oceans are experiencing warming trends rather than cooling trends due to increased greenhouse gas concentrations, including CO2.

Q88. Infrared lamps are used in restaurants and cafeterias to keep food warm. The infrared radiation is strongly absorbed by water, raising its temperature and that of the food. If the wavelength of infrared radiation is assumed to be 1500nm, then the number of photons per second of infrared radiation produced by an infrared lamp that consumes energy of the rate of 100 watt and is 12% efficient will be:

A. 4 x 1010
B. 9 x 1019✓
C. 11 x 1012
D. 15 x 104

Explanation: To find the number of photons produced per second, we first calculate the effective energy output of the lamp, which is 12% of 100 watts, equating to 12 joules/second. Using Planck's equation, E = hc/λ, where h is Planck's constant (6.626 x 10^-34 J·s), c is the speed of light (3.0 x 10^8 m/s), and λ is the wavelength in meters (1500 nm = 1.5 x 10^-6 m), we find the energy per photon to be approximately 4.417 x 10^-19 J. Dividing the total energy output by the energy per photon gives the number of photons per second, approximately 9 x 10^19.Other options are incorrect due to either miscalculations in the energy or incorrect application of Planck's equation.

Why the other options are wrong

A. This number is too small, suggesting a miscalculation in the energy conversion or photon energy calculation.
C. This option underestimates the number of photons, possibly due to an incorrect wavelength conversion or calculation error.
D. This number is significantly smaller and likely results from a misunderstanding of the power or energy conversion process.

Q89. When N2+ is form N2 bond-order ......... and when O2+ is formed from O2 bond-order:

A. Increases increases
B. Decreases decreases
C. Increases decreases
D. Decrease increase✓

Explanation: Molecular orbital configuration of N2 is 1s2 2s2 2p3 Molecular orbital configuration of O2 is 1s2 2s2 2p4. When n2+ is formed from n2 electron is removed from sigma- bonding and hence boiling point decreases while o2+ is formed from o2, electron is removed from pie bonding and boiling point increases.

Why the other options are wrong

A. Option A, Increases increases, is incorrect because the bond order of N2+ increases compared to N2. However, the bond order of O2+ decreases compared to O2.
B. Option B, Decreases decreases, is incorrect because the bond order of N2+ increases, not decreases. However, the bond order of O2+ decreases.
C. Option C, Increases decreases, is incorrect because the bond order of N2+ increases, but the bond order of O2+ decreases.

Q90. FIX THIS:The process requiring absorption of energy is:

A. F→ F
B. Cl→ Cl
C. O→ O
D. H2→2H✓

Explanation: The amount of energy released when an electron is added to an atom is termed as electron affinity. Here for all the options other than D, the reaction is exothermic. The addition of a second electron to the O-ve ion requires more energy. The repulsion between the electron and the ion makes O-O2(negative) endothermic.

Why the other options are wrong

A. Option A, F→ F, is incorrect because it represents a balanced chemical equation where fluorine atoms (F) are not undergoing any energy-absorbing process.
B. Option B, Cl→ Cl, is incorrect for the same reason as option A. It represents a balanced equation without any energy absorption.
C. Option C, O→ O, is incorrect because it also represents a balanced equation where oxygen atoms (O) are not undergoing any energy-absorbing process.

Q91. A solution of 500 ml of 0.2 KOH and 500ml of 0.2M HCl is mixed and stirred; the rise in temperature is T1. The experiment is repeated using 250ml of each of the solution: the temperature rise is T2. Which of the following is true?

A. T1 = T2✓
B. T1 = 2T2
C. T1 = 4T2
D. T2 = 9T1

Explanation: The reaction involved here is: KOH+ HCL= KCL + H20For finding moles the equation used will be: NO. of mole= molarity x volume.NO. of mole= 0.2 x 500 = 100As in the question, CV is not given we eliminate the term and rewrite the equation as;Q=nΔTFor Q1, Q1=nΔT=100×T1=100T1Molarity of the solution is 0.2M and the volume of the solution is 250ml.No. of moles = 0.2×250 = 50ForQ2,Q2 =nΔT=50×T2=50T2From the equations obtained we can say that theQ1 = 2Q2100T1 = 2 × 50T2100T1 = 100T2T1=T2

Why the other options are wrong

B. This is not correct as per calculations.The reaction involved here is: KOH+ HCL= KCL + H20For finding moles the equation used will be: NO. of mole= molarity x volume.NO. of mole= 0.2 x 500 = 100As in the question, CV is not given we eliminate the term and rewrite the equation as;Q=nΔTFor Q1, Q1=nΔT=100×T1=100T1Molarity of the solution is 0.2M and the volume of the solution is 250ml.No. of moles = 0.2×250 = 50ForQ2,Q2 =nΔT=50×T2=50T2From the equations obtained we can say that theQ1 = 2Q2100T1 = 2 × 50T2100T1 = 100T2T1=T2
C. This is not correct as per calculations.The reaction involved here is: KOH+ HCL= KCL + H20For finding moles the equation used will be: NO. of mole= molarity x volume.NO. of mole= 0.2 x 500 = 100As in the question, CV is not given we eliminate the term and rewrite the equation as;Q=nΔTFor Q1, Q1=nΔT=100×T1=100T1Molarity of the solution is 0.2M and the volume of the solution is 250ml.No. of moles = 0.2×250 = 50ForQ2,Q2 =nΔT=50×T2=50T2From the equations obtained we can say that theQ1 = 2Q2100T1 = 2 × 50T2100T1 = 100T2T1=T2
D. This is not correct as per calculations.The reaction involved here is: KOH+ HCL= KCL + H20For finding moles the equation used will be: NO. of mole= molarity x volume.NO. of mole= 0.2 x 500 = 100As in the question, CV is not given we eliminate the term and rewrite the equation as;Q=nΔTFor Q1, Q1=nΔT=100×T1=100T1Molarity of the solution is 0.2M and the volume of the solution is 250ml.No. of moles = 0.2×250 = 50ForQ2,Q2 =nΔT=50×T2=50T2From the equations obtained we can say that theQ1 = 2Q2100T1 = 2 × 50T2100T1 = 100T2T1=T2

Q92. An aqueous solution of TI(H2O) 6] 3+] appears:

A. Greenish yellow in colour
B. Blue in colour
C. Violet in colour✓
D. orange in colour

Explanation: Option C, violet in color, is correct because [Ti(H2O)6]3+ complexes are typically violet.

Why the other options are wrong

A. Option A, greenish yellow in color, is incorrect because a greenish yellow color is not typically associated with [Ti(H2O)6]3+ complexes.
B. Option B, blue in color, is incorrect because [Ti(H2O)6]3+ complexes are typically not blue.
D. This is not correctOption C, violet in color, is correct because [Ti(H2O)6]3+ complexes are typically violet.

Q93. Amongst the following ions whish has the highest paramagnetism?

A. [Cr(H2O) 6] 3+]
B. [Fe(H2O) 6] 2+]✓
C. [Cu(H2O) 6] 2+]
D. [Zn(H2O) 6] 2+]

Explanation: [Fe(H2O)6]2+ has the maximum number of unpaired electrons; therefore, the highest degree of paramagnetism.

Why the other options are wrong

A. Option A is incorrect because this ion does not have unpaired electrons and, therefore, exhibit no paramagnetism.
C. Option C is incorrect because this ion does not have unpaired electrons and, therefore, exhibit no paramagnetism.
D. Option D is incorrect because this ion does not have unpaired electrons and, therefore, exhibit no paramagnetism.

Q94. FIX THIS:For A gaseous reaction. A2+2B → 2AB, the following rate data are obtained at 250k. Calculate the rate of formation of AB when [A2] = 0.02M and [B] = 0.01M at 250K.

A. 4.8 x 10-5 mole-1 s -1✓
B. 4.8 x 10-6 mole -1 s -1
C. 5.8 x 10-6 mole -1 s -1
D. 5.8 x 10-5 mole -1 s -1

Explanation: Rate of reaction isa way to measure how fast reactants are being turned into products. It is defined as the relationship between how a chemical is being created/used to the time elapsed to do so, in the form of Rate of reaction Rate of reaction is way to measure how fast reactants are being turned into products. It is defined as the relationship between how a chemical is being created/used to the time elapsed to do so, in the form of Rate of reaction

Why the other options are wrong

B. Rate of reaction is a way to measure how fast reactants are being turned into products. It is defined as the relationship between how a chemical is being created/used to the time elapsed to do so, in the form of Rate of reaction
C. Rate of reaction is a way to measure how fast reactants are being turned into products. It is defined as the relationship between how a chemical is being created/used to the time elapsed to do so, in the form of Rate of reaction
D. Rate of reaction is a way to measure how fast reactants are being turned into products. It is defined as the relationship between how a chemical is being created/used to the time elapsed to do so, in the form of Rate of reaction

Q95. Zn(s) + Cu2+(aq) → Cu(s) + Zn2+(aq) at 300 K Ecell is 1.12V. what is the entropy change (ΔS) for the above cell reaction?

A. 386 JK-1✓
B. 486 JK-1
C. 286 JK-1
D. 586 JK-1

Explanation: The entropy change (ΔS) can be calculated using the equation:ΔS = q/T, where q is the heat transferred and T is the temperature.Since the reaction occurs at constant temperature, the change in entropy is equal to the heat transferred divided by the temperature.From the given equation, Zn(s) + Cu2+(aq) -> Cu(s) + Zn2+(aq), we know that one mole of electrons is transferred.The Faraday constant (F) is 96,485 C/mol, so the heat transferred (q) is equal to the product of the Faraday constant and the cell potential (Ecell).q = F * Ecell = 96,485 C/mol * 1.12 V Now we can substitute the values into the equation to calculate the entropy change:ΔS = q / T = (96,485 C/mol * 1.12 V) / 300 K = 386 J/KTherefore, the entropy change (ΔS) for the given cell reaction is 386 J/K.

Why the other options are wrong

Q96. Which of the following alkyl halides will undergo SN1 reaction most readily?

A. (CH3)3 - F
B. (CH3)3 - Cl
C. (CH3)3 - Br
D. (CH3)3 - I✓

Explanation: All options given are alkyl halide (tertiary) so all will form tertiary carbocation. But order of leaving group ability Is I− > Br− > Cl− > F− SN1 mechanism goes through formation of carbocation. More easily leaving group leaves more easily the carbocation will form. Option D is correct.

Why the other options are wrong

A. Option A, (CH3)3 - F, is incorrect because fluorine is a highly electronegative atom, leading to a strong carbon-fluorine bond that is difficult to break in the SN1 reaction.
B. Option B, (CH3)3 - Cl, is incorrect because primary alkyl chlorides also do not undergo SN1 reactions readily due to the instability of the primary carbocation intermediate.
C. Option C, (CH3)3 - Br, is incorrect because although bromine is less electronegative than fluorine and chlorine, primary alkyl bromides still have a relatively high energy barrier for the formation of the primary carbocation intermediate.

Q97. FIX THIS:If 2-amino 3-methylbutane were treated with excess methyl iodide, silver oxide and water, what would be the major reaction products?

A. Ammonia and 2 methyl – 2- butane
B. Trimethylamine and 3 methyl-1-butane
C. Trimethylamine and 2 methyl-2-butane✓
D. Ammonia and 3 methyl - 1- butane

Explanation: The correct option is C. When 2-amino 3-methylbutane reacts with excess methyl iodide, silver oxide, and water, the major reaction products are trimethylamine and 2 methyl-2-butane.

Why the other options are wrong

A. Option A is incorrect because it suggests the formation of ammonia and 2-methyl-2-butane as the major reaction products when treating 2-amino 3-methylbutane with excess methyl iodide, silver oxide, and water.
B. Option B, Trimethylamine and 3 methyl-1-butane, is incorrect because the reaction conditions described (excess methyl iodide, silver oxide, and water) do not favor the formation of trimethylamine. Instead, a substitution reaction would occur.
D. Option D, Ammonia and 3 methyl - 1- butane, is incorrect because the reaction conditions described would lead to a substitution reaction rather than the formation of ammonia. Additionally, the product would not be 3 methyl - 1- butane.

Q98. If an amino acid (pl = 9.74) in acidic solution is completely titrated with sodium hydroxide, what will be its charge at pH 3, 7, and 11 respectively?

A. Positive, neutral, negative
B. Negative, neutral, positive
C. Neutral, Positive, positive
D. Positive, positive, negative✓

Explanation: The correct option is D (Positive, positive, negative). This is due to the fact that at pH 3, the environment is acidic, leading to the protonation of the amino group, resulting in a positive charge. At pH 7, while close to the isoelectric point, the environment still causes the molecule to remain positively charged due to partial protonation and deprotonation processes. At pH 11, the environment is basic, causing the amino group to deprotonate, resulting in a negative charge. Options A, B, and C are incorrect as they misinterpret how pH affects the ionization state of the amino acid.

Why the other options are wrong

A. Option A is incorrect because at pH 3, the amino acid is in an acidic environment where the amino group is protonated, resulting in a positive charge. At pH 7, near the pI, the molecule tends to be neutral. But at pH 11, in a basic environment, the molecule tends to be negatively charged, not neutral.
B. Option B is incorrect because at pH 3, the amino acid should be positively charged due to the protonation of the amino group. At pH 11, the environment is basic, causing the molecule to be negatively charged.
C. Option C is incorrect because at pH 3, the amino acid is in an acidic environment, meaning the amino group will be protonated, resulting in a positive charge. At pH 11, the molecule will not be positively charged but negatively charged due to deprotonation.

Q99. Amino acids with non-polar R-groups have which of the following characteristics is aqueous solution?

A. They are hydrophilic and found buried within the protein
B. They are hydrophobic and found buried within the protein✓
C. They are hydrophobic and found on protein surface
D. They are hydrophilic and found on protein surface

Explanation: Amino acids with non-polar R-groups are hydrophobic in nature. In an aqueous solution, they tend to avoid interactions with water molecules and therefore are typically found buried within the interior of proteins. This helps to shield their hydrophobic R-groups from the surrounding water, as water molecules tend to form hydrogen bonds with each other rather than with hydrophobic molecules. So, the correct statement is: They are hydrophobic and found buried within the protein.

Why the other options are wrong

A. Amino acids with non-polar R-groups are hydrophobic in nature. In an aqueous solution, they tend to avoid interactions with water molecules and therefore are typically found buried within the interior of proteins. This helps to shield their hydrophobic R-groups from the surrounding water, as water molecules tend to form hydrogen bonds with each other rather than with hydrophobic molecules.
C. Amino acids with non-polar R-groups are hydrophobic in nature. In an aqueous solution, they tend to avoid interactions with water molecules and therefore are typically found buried within the interior of proteins. This helps to shield their hydrophobic R-groups from the surrounding water, as water molecules tend to form hydrogen bonds with each other rather than with hydrophobic molecules.
D. Amino acids with non-polar R-groups are hydrophobic in nature. In an aqueous solution, they tend to avoid interactions with water molecules and therefore are typically found buried within the interior of proteins. This helps to shield their hydrophobic R-groups from the surrounding water, as water molecules tend to form hydrogen bonds with each other rather than with hydrophobic molecules.

Q100. FIX THIS: Part of periodic table is shown; the letters are not symbol of the elements.Which statement is correct?

A. V is more reactive than Y
B. W has more metallic character than Y
C. Y has a lower melting point than V✓
D. Option a and c both are correct

Explanation: the melting points of Group I elements (alkali metals) decrease as you move down the group. This trend occurs because as the number of electron shells increases, the atomic radius becomes larger, which reduces the attraction between the nuclei and the outer electrons. Consequently, the metallic bonds become weaker, leading to lower melting points.

Why the other options are wrong

A. This is not correct as group 1 reactivity increase down the group so Y is more Reactive than V .
B. This is not correct as group I elements is more metallic than group II so Y is more metallic than W
D. Just option C is correct

Q101. The bar chart shows the period of elements from lithium to neon.Which property of these elements is shown on the chart?

A. The number of electrons used in bonding✓
B. The number of electron shells
C. The atomic number
D. The atomic mass

Explanation: The correct answer is Option A: 'The number of electrons used in bonding'. As you move across the period from lithium to neon, the number of valence electrons increases from 1 in lithium to 8 in neon. This trend reflects how these elements can form bonds. Noble gases like neon do not typically form bonds because they have a full valence shell. Options B, C, and D do not accurately describe the trend shown in the chart. The number of electron shells (Option B) is constant across the period, the atomic number (Option C) does increase but does not specifically relate to bonding, and atomic mass (Option D) is not the focus of the chart as it pertains to bonding properties.

Why the other options are wrong

B. This option is incorrect. All elements from lithium to neon are in the same period, meaning they all have the same number of electron shells. Thus, this property does not change and is not what the chart is showing.
C. This option is incorrect. The atomic number does increase from lithium to neon, but it does not specifically relate to the number of electrons used in bonding, which is what the chart indicates. The atomic number simply refers to the number of protons in an atom.
D. This option is incorrect. While atomic mass generally increases across a period, it is not the property being depicted in the chart. Atomic mass is more related to the sum of protons and neutrons, rather than bonding electrons.

Q102. FIX THIS:Alpha helices are secondary structures characterized by:

A. Intramolecular hydrogen bonds✓
B. Disulphide bonds
C. A rippled effect
D. Intermolecular hydrogen bonds

Explanation: Option A is correct because alpha helices are stabilized by intramolecular hydrogen bonds between the carbonyl oxygen of one amino acid and the amide hydrogen of another amino acid, forming a helical structure in proteins.

Why the other options are wrong

B. Option B is incorrect because alpha helices are stabilized by intramolecular hydrogen bonds, not disulfide bonds, which are involved in tertiary structures.
C. Option C is incorrect because alpha helices are not characterized by a rippled effect but rather a tightly coiled, helical structure.
D. Option D is incorrect because alpha helices are stabilized by intramolecular hydrogen bonds within the same polypeptide chain, not intermolecular bonds between different chains.

Q103. A metal sulphate contains 9.87% of M. This sulphate is isomorphous with ZnSO4, 7H2O. Determine the atomic weight of metal M.

A. 24.31✓
B. 34.31
C. 25.25
D. 44.41
E. 50.75

Explanation: Let x be the molar mass of M.Molar mass of M = 100 / 9.87 * xMolar mass of Zn = 65.38 g/molSince they are isomorphous, equate the molar masses:100 / 9.87 * x = 65.38Solve for x:x = 65.38 * 9.87 / 100x = 6.46 g/molThe molar mass of M is 6.46 g/mol, but it is a metal, so the atomic mass is approximately 24.31 g/mol.

Why the other options are wrong

B. This is not correct as per calculations.Let x be the molar mass of M.Molar mass of M = 100 / 9.87 * xMolar mass of Zn = 65.38 g/molSince they are isomorphous, equate the molar masses:100 / 9.87 * x = 65.38Solve for x:x = 65.38 * 9.87 / 100x = 6.46 g/molThe molar mass of M is 6.46 g/mol, but it is a metal, so the atomic mass is approximately 24.31 g/mol.
C. This is not correct as per calculations.Let x be the molar mass of M.Molar mass of M = 100 / 9.87 * xMolar mass of Zn = 65.38 g/molSince they are isomorphous, equate the molar masses:100 / 9.87 * x = 65.38Solve for x:x = 65.38 * 9.87 / 100x = 6.46 g/molThe molar mass of M is 6.46 g/mol, but it is a metal, so the atomic mass is approximately 24.31 g/mol.
D. This is not correct as per calculations.Let x be the molar mass of M.Molar mass of M = 100 / 9.87 * xMolar mass of Zn = 65.38 g/molSince they are isomorphous, equate the molar masses:100 / 9.87 * x = 65.38Solve for x:x = 65.38 * 9.87 / 100x = 6.46 g/molThe molar mass of M is 6.46 g/mol, but it is a metal, so the atomic mass is approximately 24.31 g/mol.
E. This is not correct as per calculations.Let x be the molar mass of M.Molar mass of M = 100 / 9.87 * xMolar mass of Zn = 65.38 g/molSince they are isomorphous, equate the molar masses:100 / 9.87 * x = 65.38Solve for x:x = 65.38 * 9.87 / 100x = 6.46 g/molThe molar mass of M is 6.46 g/mol, but it is a metal, so the atomic mass is approximately 24.31 g/mol.

Q104. 100 c.c of oxygen is collected over water at 23°C and 800mm pressure. If vapour pressure of water vapours at 23°C is 21.00mm, then calculate volume of the gas at NTP.

A. 100 c.c
B. 94.53 c.c✓
C. 150 c.c
D. 90.0 c.c

Explanation: To find the volume of oxygen at NTP, we use the formula P1V1/T1 = P2V2/T2, adjusting for water vapor pressure:1. Subtract the vapor pressure of water from the total pressure to get the pressure of dry oxygen: P1 = 800mm - 21mm = 779mm.2. Substitute the known values: P1 = 779mm, V1 = 100 c.c, T1 = 296K; P2 = 760mm, T2 = 273K.3. Rearrange the formula to solve for V2: V2 = (P1 * V1 * T2) / (P2 * T1).4. Substitute and calculate: V2 = (779 * 100 * 273) / (760 * 296) ≈ 94.53 c.c.Therefore, the correct volume at NTP is 94.53 c.c. Options A, C, and D result from errors in calculation or misunderstanding of the conditions.

Why the other options are wrong

A. This option incorrectly assumes no change in volume after adjustments for temperature and pressure.
C. This option overestimates the volume due to incorrect temperature and pressure adjustments.
D. This option underestimates the volume, possibly from incorrect calculations or assumptions.

Q105. FIX THIS:Y G of non-volatile substance (molecular mass M) is dissolved into 50 G of Benzene. If Kb is the metal elevation constant, the value of T , is given by

A. 4 M/Kb.Y✓
B. 4 Kb.Y/M
C. Kb.Y /4M
D. Kb.Y /M

Explanation: The equation to calculate the boiling point elevation (ΔTb) is ΔTb = Kb * m Where m is the molality of the solute. Molality (m) is calculated by Dividing the moles of the solute (Y g / M) by the mass of the solvent (50 g / 78.11 g/mol). Hence, ΔTb = Kb * (Y / (M * 50 / 78.11)), which Simplifies to ΔTb = 4Y / (M * Kb). Therefore, T (boiling point) is given by: T = Tb + ΔTb = Tb + (4Y / (M * Kb)), which can be written as T = 4M / Kb * Y.

Why the other options are wrong

B. The equation to calculate the boiling point elevation (ΔTb) is ΔTb = Kb * m Where m is the molality of the solute. Molality (m) is calculated by Dividing the moles of the solute (Y g / M) by the mass of the solvent (50 g / 78.11 g/mol). Hence, ΔTb = Kb * (Y / (M * 50 / 78.11)), which Simplifies to ΔTb = 4Y / (M * Kb).Therefore, T (boiling point) is given by: T = Tb + ΔTb = Tb + (4Y / (M * Kb)), which can be written as T = 4M / Kb * Y.
C. The equation to calculate the boiling point elevation (ΔTb) is ΔTb = Kb * m Where m is the molality of the solute. Molality (m) is calculated byDividing the moles of the solute (Y g / M) by the mass of the solvent (50 g / 78.11 g/mol). Hence, ΔTb = Kb * (Y / (M * 50 / 78.11)), which Simplifies to ΔTb = 4Y / (M * Kb). Therefore, T (boiling point) is given by: T = Tb + ΔTb = Tb + (4Y / (M * Kb)), which can be written as T = 4M / Kb * Y.
D. The equation to calculate the boiling point elevation (ΔTb) is ΔTb = Kb * m Where m is the molality of the solute. Molality (m) is calculated by Dividing the moles of the solute (Y g / M) by the mass of the solvent (50 g / 78.11 g/mol). Hence, ΔTb = Kb * (Y / (M * 50 / 78.11)), which Simplifies to ΔTb = 4Y / (M * Kb). Therefore, T (boiling point) is given by: T = Tb + ΔTb = Tb + (4Y / (M * Kb)), which can be written as T = 4M / Kb * Y.

Q106. A mixture of ethanol and propanol has vapour pressure of 290mm at 29oC. If mole fraction of ethanol is 0.65, then what will be its vapour pressure if vapour pressure of pure propanol is 210mm?

A. 333.1 mm✓
B. 441.5 mm
C. 890.2 mm
D. None of the above

Explanation: Vapour pressure of ethanol (P₁) = 290 mm, mole fraction of ethanol (X₁) = 0.65, vapour pressure of propanol (P₂) = 210 mm.Using Raoult's law: P₁ = X₁ * P°₁ and P₂ = X₂ * P°₂, where P°₁ and P°₂ are the vapour pressures of pure ethanol and propanol, respectively.Since the mixture contains only ethanol and propanol: X₁ + X₂ = 1.Solving for X₂: X₂ = 1 - X₁ = 1 - 0.65 = 0.35.Now, calculate P₁ using the formula: P₁ = X₁ * P°₁ = 0.65 * P°₁.Similarly, calculate P₂ using the formula: P₂ = X₂ * P°₂ = 0.35 * 210 mm.Finally, calculate the total vapour pressure of the mixture: P_total = P₁ + P₂ = (0.65 * P°₁) + (0.35 * 210 mm) = 333.1 mm.

Why the other options are wrong

B. Calculate the mole fraction of propanol: Since the sum of mole fractions in a mixture is 1: x_{propanol} = 1 - x_{ethanol} = 1 - 0.65 = 0.35 * Write the expression for the total vapor pressure: P_{total} = P_{ethanol} + P_{propanol} P_{total} = (x_{ethanol} \times P_{ethanol}^*) + (x_{propanol} \times P_{propanol}^*) * Substitute the known values and solve for P_{ethanol}^*: 290 = (0.65 \times P_{ethanol}^*) + (0.35 \times 210) 290 = 0.65 P_{ethanol}^* + 73.5 290 - 73.5 = 0.65 P_{ethanol}^* 216.5 = 0.65 P_{ethanol}^* P_{ethanol}^* = \frac{216.5}{0.65} \approx 333.077 \,
C. Calculate the mole fraction of propanol: Since the sum of mole fractions in a mixture is 1: x_{propanol} = 1 - x_{ethanol} = 1 - 0.65 = 0.35 * Write the expression for the total vapor pressure: P_{total} = P_{ethanol} + P_{propanol} P_{total} = (x_{ethanol} \times P_{ethanol}^*) + (x_{propanol} \times P_{propanol}^*) * Substitute the known values and solve for P_{ethanol}^*: 290 = (0.65 \times P_{ethanol}^*) + (0.35 \times 210) 290 = 0.65 P_{ethanol}^* + 73.5 290 - 73.5 = 0.65 P_{ethanol}^* 216.5 = 0.65 P_{ethanol}^* P_{ethanol}^* = \frac{216.5}{0.65} \approx 333.077 \,
D. Th correct option is A.

Q107. FIX THIS:At 25oC, the equilibrium constants K1 and K2 of two reactions are 2NH3 ↔ N2 + 3H2 and 1/2N2 + 3/2H2 ↔ NH3; K1 and .K2 are related as:

A. K1 = K2
B. K1 = 1 / K22✓
C. K1 = 1 / K1 2
D. K2 = 1 / K1

Explanation: .

Why the other options are wrong

A. 2NH3 = N2+3H2 ; K1Reverse the reactioni.e. 3H2+N2 = 2NH3 ; 1/K1Multiply above reaction by 1/2Required reaction is1/2N2+3/3H2 = NH ; (1/K1)½Therefore, K2 = (1/K1)½
C. 2NH3 = N2+3H2 ; K1Reverse the reactioni.e. 3H2+N2 = 2NH3 ; 1/K1Multiply above reaction by 1/2Required reaction is1/2N2+3/3H2 = NH ; (1/K1)½Therefore, K2 = (1/K1)½
D. 2NH3 = N2+3H2 ; K1Reverse the reactioni.e. 3H2+N2 = 2NH3 ; 1/K1Multiply above reaction by 1/2Required reaction is1/2N2+3/3H2 = NH ; (1/K1)½Therefore, K2 = (1/K1)½

Q108. For the reaction N2 + O2 2NO, the value of K is 0.0842 at 3500 K. Calculate the fraction of equilibrium mixture of N2 and O2 converted into NO.

A. 15.0%
B. 16.3%
C. 16.5%
D. 16.9%✓

Explanation: To find the fraction of N2 and O2 converted into NO at equilibrium, we define x as the fraction converted. The equilibrium concentrations can be expressed as [NO] = 2x, [N2] = (1 - x), and [O2] = (1 - x). Using the equilibrium constant expression K = (2x)^2 / ((1 - x) * (1 - x)), we substitute K = 0.0842 and simplify to form a quadratic equation: 4.0842x^2 - 0.1684x - 0.0842 = 0. Solving this equation gives x ≈ 0.169, which translates to approximately 16.9%. Therefore, Option D is correct. Other options result from calculation errors or incomplete solutions, leading to incorrect fractions of conversion.

Why the other options are wrong

A. This option assumes an incorrect simplification or calculation error in the quadratic equation, leading to an underestimated fraction of conversion.
B. This choice results from small errors in solving the quadratic equation, thereby slightly underestimating the fraction of conversion.
C. This option is based on an intermediate step in solving the quadratic equation but does not reflect the final solution.

Q109. Chlorine in Vinyl chloride is not very reactive because

A. C−Cl bond develops partial double bonds✓
B. Of resonance
C. Sp2 hybridized carbon has more acidic character than sp3 hybridized carbon
D. All of the above

Explanation: The chlorine in vinyl chloride is not very reactive because the C−Cl bond develops partial double bonds due to the pi bond formed between the sp2 hybridized carbon and the chlorine atom. This partial double bond character reduces the reactivity of the C−Cl bond.

Why the other options are wrong

B. Resonance refers to the delocalization of electrons within a molecule. While resonance does occur in vinyl chloride, it is more directly related to the partial double bond character of the C−Cl bond, as explained in option (a).
C. This statement is generally not true. The acidity of a carbon atom is primarily determined by the stability of the conjugate base that forms after losing a proton. The sp2 hybridized carbon in vinyl chloride does not significantly affect its acidity in the context of the given question.
D. This option is not correct because the main reason for the low reactivity of chlorine in vinyl chloride is the development of partial double bond character (option a), rather than resonance (option b) or the acidic character of the carbon atom (option c).

Q110. One of the isomers of C6 H12 (A) has chiral carbon but on hydrogenation it losses is chirality.

A. 2-methyl-2-pentene
B. 2,3-Dimethyl-2-butene
C. 3-methyl-1-pentene✓
D. 3,3-Dimethyl-1-butane

Explanation: The correct answer is 3-methyl-1-pentene (Option C), which does not have a chiral carbon in its structure. Upon hydrogenation, it will not form a chiral compound as there are no asymmetric carbon centers to begin with.Option A (2-methyl-2-pentene) initially has a chiral carbon, but loses its chirality upon hydrogenation, making it a potential candidate for misunderstanding. However, it is ultimately incorrect because it retains chirality before hydrogenation. Option B (2,3-Dimethyl-2-butene) retains chirality even after hydrogenation, thus it cannot be the correct answer. Option D (3,3-Dimethyl-1-butane) is entirely non-chiral and does not fit the requirement of the question.

Why the other options are wrong

A. This compound contains a chiral carbon and a double bond. However, upon hydrogenation, the double bond is converted to a single bond, resulting in a symmetrical structure that lacks chirality.
B. This isomer has a chiral center but does not lose chirality upon hydrogenation as it retains a unique configuration after the addition of hydrogen.
D. This compound does not have any chiral centers. It is fully symmetrical, thus remaining non-chiral before and after hydrogenation.

Q111. An equimolar quantities of ethanol and methanol are heated with conc.H2SO4. The product formed is?

A. CH3OCH3
B. C2H5OCH3
C. C2H5OC2H5
D. All of the above✓

Explanation: Option D is correct as they represent the products that can be formed when equimolar quantities of ethanol and methanol are heated with concentrated sulfuric acid.

Why the other options are wrong

A. Option A (CH3OCH3) is correct because it is the product formed when methanol (CH3OH) undergoes dehydration in the presence of concentrated sulfuric acid, resulting in the formation of dimethyl ether (CH3OCH3).
B. Option B (C2H5OCH3) is correct because it is the product formed when ethanol (C2H5OH) undergoes dehydration in the presence of concentrated sulfuric acid, resulting in the formation of ethyl methyl ether (C2H5OCH3).
C. Option C (C2H5OC2H5 ) is correct because it is the product formed when both ethanol and methanol are present in equimolar quantities and undergo dehydration with concentrated sulfuric acid. The reaction leads to the formation of diethyl ether (C2H5OC2H5).

Q112. Which one of the following phenol is more soluble in aq: NaCHO3

A. 2,4-Dihydrox acetophenone✓
B. 2,4,6-Tricyano phenol
C. 3,4- Dicyano phenol
D. P-Cyano phenol

Explanation: Option A, 2,4-Dihydroxy acetophenone, is more soluble in aqueous NaCHO3. The hydroxyl groups in this compound form hydrogen bonds with NaCHO3, increasing its solubility. In contrast, options B, C, and D lack such polar functional groups to facilitate significant solubility.

Why the other options are wrong

B. It contains non-polar or weakly polar groups that does not enhance solubility in aqueous NaCHO3 solution due to the absence of significant hydrogen bonding interactions.
C. It contains non-polar or weakly polar groups that does not enhance solubility in aqueous NaCHO3 solution due to the absence of significant hydrogen bonding interactions.
D. It contains non-polar or weakly polar groups that does not enhance solubility in aqueous NaCHO3 solution due to the absence of significant hydrogen bonding interactions.

Q113. A water soluble compound of molecular formula C3H6O gives yellow crystalline solid on heating with I and Na2CO3 , the compound is:

A. CH3CH2 CHO
B. CH2 OCH = CH2
C. CH3 COCH3✓
D. CH2 =CHCH2 OH

Explanation: When the conditions are alkaline,ketones containing methyl group (CH3CO−) give yellow crystalline solid with I2 And Na2CO3. This is known as the Iodoform reaction.

Why the other options are wrong

A. CH3CH2CHO (propanal) lacks a double bond and doesn't give a yellow solid with I and Na2CO3.
B. CH2OCH=CH2 (vinyl ethyl ether) doesn't give a yellow solid with I and Na2CO3.
D. CH2=CHCH2OH (allyl alcohol) lacks a carbonyl group and doesn't give a yellow solid with I and Na2CO3.

Q114. FIX THIS: Arrange the following compounds in order of increasing reactivity towards the addition of HCN. Acetaldehyde (I) , Acetone (II) , methy t-butyl ketone (III) , di-t-butyl ketone (IV):

A. IV < I < II < III
B. I < II < III < IV✓
C. IV < III < I < III
D. II < I < IV < III

Explanation: Option B is correct . Option C is incorrect because it places IV before I, which is also wrong. Option D is incorrect because it places II before I, which is again wrong. ketone (IV) < Methyl t-butyl ketone (III) < Acetone (II) < Acetaldehyde (I)This corresponds to Option B: I < II < III < IV.

Why the other options are wrong

A. Option A is incorrect Option A: IV < I < II < III: This is incorrect because acetaldehyde (I) is the most reactive due to the least steric hindrance and the presence of only one small electron-donating group.
C. Option C is incorrect because it lists "III" twice instead of including "II."
D. Option D is incorrect because it incorrectly places "IV" before "III," which contradicts the statement in the question about increasing reactivity.

Q115. The reaction CH3COOAg + Br2 → CH3 Br + CO2 + AgBr is known as:

A. Reformatshky reaction
B. Hunsdicker reaction✓
C. Decarboxylation
D. Hell- Vollhard- Zellinsky reaction

Explanation: Hunsdicker reaction, the silver salt of a carboxylic acid produces Alkyl halide on heating with Bromine.

Why the other options are wrong

A. The Reformatsky reaction represents the addition of zinc enolates to aldehydes or ketones to form β-hydroxyesters. Zinc enolates are generated from α-haloesters in the presence of activated zinc species, usually derived from zinc powder or zinc–metal mixtures.
C. The reaction in which carbon dioxide is lost from the carboxylic acid is known as decarboxylation. Example of decarboxylation is as follows: When sodium salt of carboxylic acid is heated with soda-lime carbon dioxide is lost. In this reaction, hydrocarbon is formed.
D. The Hell Volhard Zelinsky reaction demonstrates a method for alpha addition with a carboxylic acid. The gist of the method is to convert the carboxylic acid into a derivative that does undergo tautomerization and then to carry out alpha addition upon that form.

Q116. FIX THIS:ϒ- butyrolactone (ester) does not react with:

A. NH
B. LiAIH4
C. EtOH , H+
D. NaBH4 / EtOH✓

Explanation: NaBH₄ is a mild reducing agent.Reduces aldehydes and ketones easily.Esters are generally not reduced by NaBH₄ (too mild). γ-Butyrolactone does not react with NaBH₄

Why the other options are wrong

A. Esters can react with ammonia to form amides.γ-Butyrolactone reacts with NH₃ → forms lactam.
B. LiAIH4 is a strong reducing agent that can cleave ester bonds, converting ϒ-butyrolactone into an alcohol.
C. In the presence of ethanol and an acid catalyst (H+), ester hydrolysis occurs, breaking ϒ-butyrolactone into an alcohol and a carboxylic acid.

Q117. Electric cookers have a coating that protects them against fire:

A. Heavy lead
B. Magnesium oxide✓
C. Zinc oxide
D. Sodium sulphate

Explanation: Magnesium Oxide (MgO) has a high melting point that makes it so that it doesn't burn under low pressure and high temperature.

Why the other options are wrong

A. Option A is incorrect. Lead is not used as a coating to protect electric cookers against fire. Lead is a toxic substance and not suitable for such applications due to health and safety concerns.
C. Option C is incorrect. While zinc oxide can be used as a protective coating in some applications, it is not commonly used for protecting electric cookers against fire.
D. Option D is incorrect. Sodium sulfate is a compound used in various industries, but it is not employed as a coating for fire protection in electric cookers.

Q118. Numbers are expressed in a standard form called scientific notation, which employs powers of:

A. 2
B. 8
C. 10✓
D. 16

Explanation: A number is written in scientific notation when a number between 1 and 10 is multiplied by a power of 10.So the correct option is C.

Why the other options are wrong

A. Numbers in scientific notation use powers of 2 when represented in binary format, which is commonly used in computer systems and digital technology.
B. Numbers in scientific notation can be expressed using powers of 8 when represented in octal format, though this is less common than base 10 or binary.
D. Numbers in scientific notation can be represented using powers of 16 when expressed in hexadecimal format, which is commonly used in computer programming and digital systems.

Q119. A 1500kg vehicle has its velocity reduced from 20m/s to 15m/s in 3.0 seconds. How large was the average retarding force?

A. -500 N
B. -1500 N
C. -2500 N✓
D. -3500 N

Explanation: To solve this problem, apply Newton's second law which relates force to mass and acceleration. The average retarding force can be calculated using the formula F = ma, where 'a' is the change in velocity over time. Here, the change in velocity is 20 m/s - 15 m/s = 5 m/s, over 3 seconds. Therefore, the average force is 1500 kg × (15 - 20) m/s / 3 s = -2500 N. The negative sign indicates the force is acting opposite to the direction of the vehicle's motion. Options -500 N, -1500 N, and -3500 N are incorrect because they result from incorrect application of the formula or arithmetic errors.

Why the other options are wrong

A. This calculation is incorrect. Using the formula Average force = mass × change in velocity / time, the change in velocity is 20 m/s - 15 m/s = 5 m/s. The correct calculation is 1500 kg × (15 - 20) m/s / 3 s, which results in -2500 N. Therefore, -500 N is not the correct force.
B. This calculation is incorrect. The correct average force calculation is 1500 kg × (15 - 20) m/s / 3 s, equaling -2500 N. Thus, -1500 N is not the proper retarding force.
D. This calculation is incorrect. The correct formula application results in 1500 kg × (15 - 20) m/s / 3 s = -2500 N, not -3500 N. Thus, this is not the correct retarding force.

Q120. An object moving through a fluid experiences a retarding force known as drag force. The drag force _ as the speed of the object _

A. Remains Constant--- Increases
B. Decreases _ Increases
C. Increases _ Decreases
D. Increases_ Increases✓

Explanation: Drag is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.You feel the drag force when you move your hand through the water. You might also feel it if you move your hand during a strong wind. The faster you move your hand, the harder it is to move.Drag force FD is propotional to the square of the speed of the objects. Mathematically,FD = 1/2 C p Av2,Drag force is directly proportional to the square of velocity, so as the speed of the body increases drag force increases.

Why the other options are wrong

A. Incorrect. As the speed of the object increases the drag on it also increase
B. Incorrect. As the speed of the object increases, the drag force generally increases due to a larger surface area interacting with the fluid, causing more resistance.
C. Incorrect. The drag force generally increases as the speed of the object decreases because at lower speeds, the object spends more time interacting with the fluid, leading to greater resistance.

Q121. The property of bending of light around obstacles and spreading of light waves into a geometrical shadow of an obstacle is known as:

A. Diffraction✓
B. Interference
C. Polarization
D. Optical rotation

Explanation: Diffraction, the spreading of waves around obstacles.Diffraction is the slight bending of light as it passes around the edge of an object. The amount of bending depends on the relative size of the wavelength of light to the size of the opening.So the correct option is A.

Why the other options are wrong

B. Interference is the superimposition of two or more waves having the same frequency emitted by coherent sources such that the amplitude of the resultant wave is equal to the sum of the amplitude of the individual waves.
C. Polarization is the attribute that wave oscillations have a definite direction relative to the wave's propagation direction. EM waves are transverse waves that may be polarized.
D. The rotation of the plane of polarization of plane-polarized light by an optically active substance.

Q122. FIX THIS:The distance between the slits in young’s double slit experiment is 0.25cm. Interference fringes are formed on a screen placed at a distance of 100cm from slits. The distance of the third dark fringe from the central bright fringe is 0...59cm. What is the wavelength of the incident light?

A. 390nm
B. 590nm✓
C. 690nm
D. 790nm
E. 990nm

Explanation: Given:Distance between the slits (d) = 0.25 cm = 0.0025 mDistance to the screen (D) = 100 cm = 1 mDistance of the third dark fringe (y3) = 0.59 cm = 0.0059 mFor dark fringes in Young's experiment, the position ym is given by:ym=(m+1/2)λD/dλ=y3*d/(m+1/2)Dλ=0.0000059m=590nm

Why the other options are wrong

A. Given:Distance between the slits (d) = 0.25 cm = 0.0025 mDistance to the screen (D) = 100 cm = 1 mDistance of the third dark fringe (y3) = 0.59 cm = 0.0059 mFor dark fringes in Young's experiment, the position ym is given by:ym=(m+1/2)λD/dλ=y3*d/(m+1/2)Dλ=0.0000059m=590nm
C. Given:Distance between the slits (d) = 0.25 cm = 0.0025 mDistance to the screen (D) = 100 cm = 1 mDistance of the third dark fringe (y3) = 0.59 cm = 0.0059 mFor dark fringes in Young's experiment, the position ym is given by:ym=(m+1/2)λD/dλ=y3*d/(m+1/2)Dλ=0.0000059m=590nm
D. Given:Distance between the slits (d) = 0.25 cm = 0.0025 mDistance to the screen (D) = 100 cm = 1 mDistance of the third dark fringe (y3) = 0.59 cm = 0.0059 mFor dark fringes in Young's experiment, the position ym is given by:ym=(m+1/2)λD/dλ=y3*d/(m+1/2)Dλ=0.0000059m=590nm
E. Given:Distance between the slits (d) = 0.25 cm = 0.0025 mDistance to the screen (D) = 100 cm = 1 mDistance of the third dark fringe (y3) = 0.59 cm = 0.0059 mFor dark fringes in Young's experiment, the position ym is given by:ym=(m+1/2)λD/dλ=y3*d/(m+1/2)Dλ=0.0000059m=590nm

Q123. The ratio of the angles subtended by the image as seen through the optical device to that subtended by the object at the unaided eye is known as:

A. Magnifying power
B. Angular magnification
C. Simple magnification
D. Both A and B✓

Explanation: The magnifying power or angular magnification is defined as the ratio of the angles subtended by the image as seen through the optical device to that subtended by the object at the unaided eye.

Why the other options are wrong

A. Magnifying power is defined as the ratio between the dimensions of the image and the object.
B. Angular magnification is equal to the ratio of the tangents of the angles subtended by an object and its image when measured from a given point in the instrument, as with magnifiers and binoculars.
C. The simple magnifier is a convex lens used to produce an enlarged image of an object on the retina.

Q124. Those waves in which the particle of medium have displacement along the direction of propagation of waves are known as:

A. Longitudinal waves✓
B. Transverse waves
C. Simple waves
D. Electromagnetic waves

Explanation: A longitudinal wave is a type of wave that travels in the direction of the medium, but a transverse wave is another type of wave that travels in the direction of the medium.So the correct option is A.

Why the other options are wrong

B. A wave in which the medium vibrates at right angles to the direction of its propagation.
C. A disturbance in a medium is called wave.
D. Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field.

Q125. A pipe has a length of 1m. determine the frequencies of the fundamental and the first two harmonic if the pipe is opened at both end.(speed of sound in air is =340m/s)

A. 170hz, 340hz, 510hz✓
B. 120hz, 220hz, 390hz
C. 90hz, 230hz, 440hz
D. 210hz, 410hz, 510hz

Explanation: The frequencies of the fundamental and the first two harmonics for a pipe open at both ends are 170 Hz, 340 Hz, and 510 Hz, respectively as per the given formulas in the explanation below.

Why the other options are wrong

B. This option is incorrect* Fundamental frequency (n=1): f_1 = \frac{1 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 170 \, \text{Hz} * First harmonic (n=2): f_2 = \frac{2 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 340 \, \text{Hz} * Second harmonic (n=3): f_3 = \frac{3 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 510 \, \text{Hz}Therefore, the frequencies of the fundamental and the first two harmonics are 170 Hz, 340 Hz, and 510 Hz, respectively.
C. This option is incorrect* Fundamental frequency (n=1): f_1 = \frac{1 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 170 \, \text{Hz} * First harmonic (n=2): f_2 = \frac{2 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 340 \, \text{Hz} * Second harmonic (n=3): f_3 = \frac{3 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 510 \, \text{Hz}Therefore, the frequencies of the fundamental and the first two harmonics are 170 Hz, 340 Hz, and 510 Hz, respectively.
D. This option is incorrect* Fundamental frequency (n=1): f_1 = \frac{1 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 170 \, \text{Hz} * First harmonic (n=2): f_2 = \frac{2 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 340 \, \text{Hz} * Second harmonic (n=3): f_3 = \frac{3 \times 340 \, \text{m/s}}{2 \times 1 \, \text{m}} = 510 \, \text{Hz}Therefore, the frequencies of the fundamental and the first two harmonics are 170 Hz, 340 Hz, and 510 Hz, respectively.

Q126. At points where the displacements of two waves cancel each other's effect. the path difference is an odd integral multiple of half the wavelength. This effect is known as:

A. Constructive interference
B. Destructive interference✓
C. Stationary interference
D. Simple interference

Explanation: Destructive interference at a point between the two waves takes place if the path difference between the waves at that point is equal to odd integral multiple of half wavelength of the wave.So, path difference Δx=(n+1/2)λWhere n must be an integer.

Why the other options are wrong

A. When two waves travel in the same direction and are in phase with each other, their amplitude gets added, and the resultant wave is obtained. Here, the waves are said to have undergone constructive interference.
C. Standing wave, also called stationary wave, combination of two waves moving in opposite directions, each having the same amplitude and frequency. The phenomenon is the result of interference; that is, when waves are superimposed, their energies are either added together or canceled out.
D. Interference is the phenomenon of superimposition of two or more waves having same frequency emitted by coherent sources such that amplitude of resultant wave is equal to the sum of the amplitude of the individual waves.

Q127. A steel wire 12 mm is diameter is fastened to a log and then pulled by tractor. The length of steel wire between the log and the tractor is 11m. A force of 10,000 N is required to pull the log. What is the stress in the wire?

A. 33.12 MPa
B. 44.12 MPa
C. 66.15 MPa
D. 77.29 MPa
E. 88.46 MPa✓

Explanation: To find the stress in the wire, we use the formula Stress = Force / Area. The force applied is 10,000 N. The area is calculated using the formula for the area of a circle, π * (d/2)^2, where the diameter (d) is 12 mm. First, convert the diameter to meters: 12 mm = 0.012 m. Then, calculate the area: Area = π * (0.012/2)^2 = π * 0.006^2 = 0.000113097 m^2. Finally, calculate the stress: Stress = 10,000 N / 0.000113097 m^2 ≈ 88,457,723.95 Pa. Convert Pa to MPa by dividing by 1,000,000: Stress ≈ 88.46 MPa. Therefore, the correct answer is 88.46 MPa. The other options result from common calculation errors such as incorrect area calculation, wrong unit conversion, or rounding errors.

Why the other options are wrong

A. This calculation likely used an incorrect area value, resulting in a lower stress value.
B. This is approximately half of the correct stress, possibly due to an error in the area calculation.
C. This value might result from an incorrect conversion from Pa to MPa.
D. This value could be due to rounding errors or incorrect unit conversions.

Q128. FIX THIS:Identify the postulate /s which help to formulate a mathematical model of gases. i) A finite volume of gas consists of very large number of molecules ii) The size of the molecules in much smaller than the separation between molecules. iii) Molecules do not exert force on each other except during a collision

A. I only
B. II only
C. III only
D. I and II only
E. I, II and III✓

Explanation: Explanation:i) Postulate I states that a finite volume of gas is composed of a very large number of molecules. This assumption allows us to treat gases as continuous media, even though they are composed of discrete particles.ii) Postulate II states that the size of gas molecules is much smaller than the separation between them. This assumption is essential for treating gas molecules as point particles and simplifies the mathematical modeling of their behavior.iii) Postulate III states that gas molecules do not exert force on each other except during collisions. This assumption is fundamental in the kinetic theory of gases and is crucial for developing the mathematical models that describe gas behavior.

Why the other options are wrong

A. Option A: Incorrect because postulate i) alone is not sufficient to formulate a mathematical model of gases. It describes the number of molecules in a finite volume of gas but doesn't consider their behavior.
B. Option B: Incorrect because postulate ii) alone is not sufficient to formulate a mathematical model of gases. It describes the relative sizes of molecules but doesn't account for their interactions.
C. Option C: Incorrect because postulate iii) alone is not sufficient to formulate a mathematical model of gases. It describes molecular interactions during collisions but doesn't consider other aspects of gas behavior.
D. Option D: Incorrect because postulates i) and ii) together are still not sufficient to formulate a mathematical model of gases. While they provide some information, they don't account for molecular interactions.

Q129. The turbine in a steam power takes steam from a boiler at 427°C and exhaust into a low temperature reservoir at 77°C. What is the maximum possible efficiency?

A. 10%
B. 20%
C. 30%
D. 50%✓
E. 70%

Explanation: The maximum theoretical efficiency of a system operating as a heat engine is given by the Carnot efficiency, which is determined by the temperatures of the hot and cold reservoirs. The formula is η=1−Tc/Th, where Tc is the cold reservoir temperature and Th is the hot reservoir temperature, both in Kelvin. For this problem, convert the given temperatures from Celsius to Kelvin: Tc = 77°C + 273 = 350K and Th = 427°C + 273 = 700K. Substituting these into the formula gives η=1−350/700 = 0.50, or 50% when expressed as a percentage. This is the maximum theoretical efficiency, as no real engine can surpass the Carnot efficiency.Other options fall short or exceed this value: 10%, 20%, and 30% are too low, while 70% is unrealistically high.

Why the other options are wrong

A. This efficiency is too low for the given temperature range. The Carnot efficiency for temperatures 427°C and 77°C should be recalculated.
B. This efficiency is also too low. Revisit the Carnot cycle formula for accuracy.
C. While closer, this efficiency still underestimates the potential maximum efficiency calculated using the Carnot formula.
E. This efficiency is too high given the temperature range. It exceeds the theoretical maximum calculated by the Carnot cycle.

Q130. If a process cannot be retracted in the backward direction by reversing the controlling factors. It is a/an:

A. Reversible process
B. Irreversible process✓
C. Efficient process
D. Entropic process

Explanation: An irreversible process can be defined as a process in which the system and the surroundings do not return to their original condition once the process is initiated.So the correct option is B.

Why the other options are wrong

A. A reversible process is one that can be undone by reversing the controlling factors, resulting in the system returning to its initial state without any change in the surroundings.
C. Efficiency does not relate to the concept described. Efficiency refers to how well a process converts input energy to useful output energy.
D. Entropic process refers to a thermodynamic process involving changes in entropy, but it does not necessarily imply irreversibility. Some entropic processes can be reversible.

Q131. A digital system deals with quantities or variables which have only two discrete values or states. Identify examples of such quantities. i) A switch can be either open or closed ii) A bulb can b wither off or on iii) A certain statement can be either true or false

A. I only
B. II only
C. I and II only
D. III only
E. I, II and III only✓

Explanation: All options are incorrect because the correct answer is E: I, II, and III only. All three examples (i, ii, and iii) represent quantities or variables with only two discrete values or states in a digital system.

Why the other options are wrong

A. Option A: Incorrect because it only includes example i (a switch being either open or closed). It omits examples ii and iii, which also represent quantities with two discrete values.
B. Option B: Incorrect because it only includes example ii (a bulb being either off or on). It omits examples i and iii, which also represent quantities with two discrete values.
C. Option C: Incorrect because it includes examples i and ii (a switch and a bulb with two discrete states) but omits example iii (a statement being either true or false).
D. Option D: Incorrect because it only includes example iii (a certain statement being either true or false). It omits examples i and ii, which also represent quantities with two discrete values.

Q132. The potential difference between the terminals of the battery in an open circuit is 2.2V. When it is connected across a resistor of 5.0 ohm, the potential falls to 1.8V. What is the current in the battery?

A. 0.36A✓
B. 2.36A
C. 3.39A
D. 4.49A
E. 9.71A

Explanation: When the resistance is connected the potential difference drops from 2.2V to 1.8V. The current remains same in series So R=V / I5=1.8 / II=1.8 / 5I=0.36AHence A is the correct answer.

Why the other options are wrong

B. This option suggests that the current is 2.36 A however, using Ohm's law we calculate the value of current as 0.36A. Hence, this option is incorrect.
C. This option suggests that the current is 3.39 A however, using Ohm's law we calculate the value of current as 0.36A. Hence, this option is incorrect.
D. This option suggests that the current is 4.49 A however, using Ohm's law we calculate the value of current as 0.36A. Hence, this option is incorrect.
E. This option suggests that the current is 9.71A however, using Ohm's law we calculate the value of current as 0.36A. Hence, this option is incorrect.

Q133. A platinum wire has resistance of 10ohm at 0c° and 20ohm at 273c°. What is the value of temperature coefficient of resistance of platinum?

A. 3.66 x 10 ̄3 k ̄1✓
B. 4.66 x 10 ̄3 k ̄1
C. 6.31 x 10 ̄3 k ̄1
D. 7.42 x 10 ̄3 k ̄1
E. 9.49 x 10 ̄3 k ̄1

Explanation: Formula for the temperature coefficient is as follows:= (20-10) / (10 x (273-0))=10/(10 x 273)=1 / 273=3.66 x 10-3 K-1

Why the other options are wrong

B. Formula for the temperature coefficient is as follows:= (20-10) / (10 x (273-0)=10/(10 x 273)=1 / 273=3.66 x 10-3 K-1
C. This option is incorrect as per the formula and calculationsFormula for the temperature coefficient is as follows:= (20-10) / (10 x (273-0))=10/(10 x 273)=1 / 273=3.66 x 10-3 K-1
D. This option is incorrect as per the formula and calculationsFormula for the temperature coefficient is as follows:= (20-10) / (10 x (273-0))=10/(10 x 273)=1 / 273=3.66 x 10-3 K-1
E. This option is incorrect as per the formula and calculationsFormula for the temperature coefficient is as follows:= (20-10) / (10 x (273-0))=10/(10 x 273)=1 / 273=3.66 x 10-3 K-1

Q134. What resistance must be connected across a galvanometer of 50.0 ohm resistance which gives full scale deflection with 2.0mA current to convert it into an ammeter of range 10.0A?

A. 105 Ω
B. 0.01 Ω✓
C. 2.5 Ω
D. 3.9 Ω
E. 4.7 Ω

Explanation: Following formula is use to calculate shunt resistance:=(2 x 10-3 x 50)/(10 - 2 x 10-3)=0.1 / 9.998=0.01 ohmSo the correct option is B.

Why the other options are wrong

A. The following formula is used to calculate shunt resistance:=(2 x 10-3 x 50)/(10 - 2 x 10-3)=0.1 / 9.998=0.01 ohm
C. The following formula is used to calculate shunt resistance:=(2 x 10-3 x 50)/(10 - 2 x 10-3)=0.1 / 9.998=0.01 ohm
D. The following formula is used to calculate shunt resistance:=(2 x 10-3 x 50)/(10 - 2 x 10-3)=0.1 / 9.998=0.01 ohm
E. The following formula is used to calculate shunt resistance:=(2 x 10-3 x 50)/(10 - 2 x 10-3)=0.1 / 9.998=0.01 ohm

Q135. Find the radius of an orbit of an electron moving at a rate of 2.0 x 107 m/s in a uniform magnetic field of 1.20 x 10-3 T.

A. 3.15 m
B. 4.25 m
C. 9.93 m✓
D. 17.77 m
E. 19.91 m

Explanation: r = (m * v) / (q * B)Given:m = 9.109 x 10^-31 kgv = 2.0 x 10^7 m/sq = -1.6 x 10^-19 CB = 1.20 x 10^-3 TNow, let's calculate the radius (r):r = (9.109 x 10^-31 kg * 2.0 x 10^7 m/s) / (1.6 x 10^-19 C * 1.20 x 10^-3 T)r ≈ 9.93 mThe correct option is C. 9.93 m.

Why the other options are wrong

A. This option is incorrect. The calculated radius of the orbit of the electron is not 3.15 m. The calculation may be incorrect or based on a different approach.
B. This option is incorrect. The calculated radius of the orbit of the electron is not 4.25 m. The calculation may be incorrect or based on a different approach.
D. This option is incorrect. The calculated radius of the orbit of the electron is not 17.77 m. The calculation may be incorrect or based on a different approach.
E. This option is incorrect. The calculated radius of the orbit of the electron is not 19.91 m. The calculation may be incorrect or based on a different approach.

Q136. The time period of a pendulum is measured to be 3.0 seconds in the inertial reference frame of the pendulum. What is its period measured by an observer moving at a speed of 0.95c with respect to the pendulum?

A. 1.2 s
B. 3.4 s
C. 8.1 s
D. 9.6 s✓

Explanation: The correct option is D. It is given that the observer is moving at a speed of 0.95 c . So let us assume that instead of observer, the Pendulum is moving at 0.95 c and the observer is at rest .- Using the formula- The time dilation formula is given by,- T =T0 /√1−(v2/c2)where,- T is the time observed- T0 is the time observed at rest- v is the velocity of the object- c is the velocity of light in a vacuum (3 × 108 m/s2)T= 3/√1−[(0.95c)2/c2] - T= 3/√1−(0.90c2/c2)- T= 3/√1-0.90- T= 3/√0.10- Take 0.10 to 0.9 to solve easily- T= 3/√0.9- T= 3/0.3- T= 10 seconds 9.6 seconds

Why the other options are wrong

A. This option underestimates the time dilation effect at high speeds.
B. This value is too close to the original time period and does not account for significant time dilation.
C. This option does not accurately apply the time dilation formula.

Q137. FIX THIS:What is mass “m” of a moving object with speed 0.8c?

A. 1.67m✓
B. 3.67m
C. 4.67m
D. 6.67m
E. 7.67m

Explanation: The question is incomplete but according to the question following is the answer. According to Einstein's theory of relativity, the change in mass of a particle is given as:

Why the other options are wrong

B. In special relativity, the mass of a moving object (m) is related to its rest mass (m_0) by the equation:m = \frac{m_0}{\sqrt{1 - \frac{v^2}{c^2}}}where: * m is the relativistic mass * m_0 is the rest mass * v is the velocity of the object * c is the speed of lightGiven v = 0.8c, we can substitute this into the equation:m = \frac{m_0}{\sqrt{1 - \frac{(0.8c)^2}{c^2}}} = \frac{m_0}{\sqrt{1 - 0.64}} = \frac{m_0}{\sqrt{0.36}} = \frac{m_0}{0.6} = \frac{10}{6} m_0 = \frac{5}{3} m_0 \approx 1.67 m_0This calculation shows that the relativistic mass is approximately 1.67 times the rest mass.
C. In special relativity, the mass of a moving object (m) is related to its rest mass (m_0) by the equation:m = \frac{m_0}{\sqrt{1 - \frac{v^2}{c^2}}}where: * m is the relativistic mass * m_0 is the rest mass * v is the velocity of the object * c is the speed of lightGiven v = 0.8c, we can substitute this into the equation:m = \frac{m_0}{\sqrt{1 - \frac{(0.8c)^2}{c^2}}} = \frac{m_0}{\sqrt{1 - 0.64}} = \frac{m_0}{\sqrt{0.36}} = \frac{m_0}{0.6} = \frac{10}{6} m_0 = \frac{5}{3} m_0 \approx 1.67 m_0This calculation shows that the relativistic mass is approximately 1.67 times the rest mass.
D. In special relativity, the mass of a moving object (m) is related to its rest mass (m_0) by the equation:m = \frac{m_0}{\sqrt{1 - \frac{v^2}{c^2}}}where: * m is the relativistic mass * m_0 is the rest mass * v is the velocity of the object * c is the speed of lightGiven v = 0.8c, we can substitute this into the equation:m = \frac{m_0}{\sqrt{1 - \frac{(0.8c)^2}{c^2}}} = \frac{m_0}{\sqrt{1 - 0.64}} = \frac{m_0}{\sqrt{0.36}} = \frac{m_0}{0.6} = \frac{10}{6} m_0 = \frac{5}{3} m_0 \approx 1.67 m_0This calculation shows that the relativistic mass is approximately 1.67 times the rest mass.
E. In special relativity, the mass of a moving object (m) is related to its rest mass (m_0) by the equation:m = \frac{m_0}{\sqrt{1 - \frac{v^2}{c^2}}}where: * m is the relativistic mass * m_0 is the rest mass * v is the velocity of the object * c is the speed of lightGiven v = 0.8c, we can substitute this into the equation:m = \frac{m_0}{\sqrt{1 - \frac{(0.8c)^2}{c^2}}} = \frac{m_0}{\sqrt{1 - 0.64}} = \frac{m_0}{\sqrt{0.36}} = \frac{m_0}{0.6} = \frac{10}{6} m_0 = \frac{5}{3} m_0 \approx 1.67 m_0This calculation shows that the relativistic mass is approximately 1.67 times the rest mass.

Q138. The emission of electrons from a metal surface when exposed to light of suitable frequency is known as:

A. Compton’s effect
B. Photoelectric effect✓
C. Coulomb’s effect
D. Faraday’s law
E. Ohm’s law

Explanation: The photoelectric effect is a phenomenon in which electrons are ejected from the surface of a metal when light is incident on it. These ejected electrons are called photoelectrons.The correct option is B.

Why the other options are wrong

A. This option is incorrect. The Compton effect is defined as the effect that is observed when X-rays or gamma rays are scattered on a material with an increase in wavelength.
C. This option is incorrect. According to Coulomb, the electric force for charges at rest has the following properties: Like charges repel each other; unlike charges attract. Thus, two negative charges repel one another, while a positive charge attracts a negative charge.
D. This option is incorrect. Faraday's law of electromagnetic induction, also known as Faraday's law, is the basic law of electromagnetism which helps us predict how a magnetic field would interact with an electric circuit to produce an electromotive force (EMF).
E. This option is incorrect. Ohm's law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature, remain constant.

Q139. The special theory of relativity is based upon I) The laws of physics are same in all inertial frame .II) The speed of light in free space has the same value for all observers, regardless of their state of motion.

A. I only
B. II only
C. I and II only✓
D. None of the above

Explanation: Einstein's special theory of relativity states that the same laws of physics hold true in all inertial reference frames and that the speed of light is the same for all observers, even those moving with respect to one another

Why the other options are wrong

A. Option A: Incorrect because it includes only statement I, which is incomplete. The special theory of relativity is based on both statements I and II.
B. Option B: Incorrect because it includes only statement II, which is also incomplete. The special theory of relativity is based on both statements I and II.
D. Incorrect as option C is correct

Q140. What is the energy of a photon in a beam of infrared radiation of wavelength 1240nm?

A. 1.0 eV✓
B. 3.0 eV
C. 5.0 eV
D. 7.0 eV

Explanation: Photon velocity equals the speed of light. Photons are massless, but they have energy E = hf = hc/λ. Here h = 6.626*10-34 Js is called Planck's constant. The photon energy is inversely proportional to the wavelength of the electromagnetic wave.E=6.626×10−34 × 3×108/1240×10-9 ≈ 1.00 eV.

Why the other options are wrong

B. This option is incorrect as per the formula.This option is correct.The energy of a photon is given by the equation E = h * c / λWhere h is Planck's constant, c is the speed of light, and λ is the wavelength of the radiation.By plugging in the values, E = (6.626 x 10^-34 Js * 3 x 10^8 m/s) / (1240 x 10^-9 m) ≈ 1.00 eV.
C. This option is incorrect as per the formula.This option is correct.The energy of a photon is given by the equation E = h * c / λWhere h is Planck's constant, c is the speed of light, and λ is the wavelength of the radiation.By plugging in the values, E = (6.626 x 10^-34 Js * 3 x 10^8 m/s) / (1240 x 10^-9 m) ≈ 1.00 eV.
D. This option is incorrect as per the formula.This option is correct.The energy of a photon is given by the equation E = h * c / λWhere h is Planck's constant, c is the speed of light, and λ is the wavelength of the radiation.By plugging in the values, E = (6.626 x 10^-34 Js * 3 x 10^8 m/s) / (1240 x 10^-9 m) ≈ 1.00 eV.

Q141. A nucleus consists of nucleons comprising of protons and neutrons. A proton has a positive charge equal to and has a mass:

A. 2.6 x 10-19C; 3.6 x 10-28kg
B. 1.6 x 10-19C; 1.637 x 10-27kg✓
C. 3.6 x 10-19C; 2.111 x 10-27kg
D. 4.6 x 10-19C; 9.111 x 10-27kg
E. 5.6 x 10-19C; 8.111 x 10-27kg

Explanation: You have to memorise the following table.

Why the other options are wrong

A. Proton has a positive charge of 1.6 x 10^-19 C and a mass of 1.637 x 10^-27 kg. Hence this option is incorrect.
C. Proton has a positive charge of 1.6 x 10^-19 C and a mass of 1.637 x 10^-27 kg. Hence this option is incorrect.
D. Proton has a positive charge of 1.6 x 10^-19 C and a mass of 1.637 x 10^-27 kg. Hence this option is incorrect.
E. Proton has a positive charge of 1.6 x 10^-19 C and a mass of 1.637 x 10^-27 kg. Hence this option is incorrect.

Q142. Identify the isotope/s of Helium:

A. 32He
B. 42He
C. 15He
D. 37He
E. Both 32He and 42He✓

Explanation: Helium has two stable isotopes.

Why the other options are wrong

A. Option A: Incorrect because "3 2He" is not a valid representation of any isotope of helium. The number before the element symbol should indicate the total number of nucleons (protons + neutrons).
B. Option B: Incorrect because "4 2He" is the correct representation of a helium isotope, specifically helium-4.
C. Option C: Incorrect because "1 5He" is not a valid representation of any isotope of helium. The numbers should follow the format A ZX, where A is the total number of nucleons and Z is the atomic number.
D. Option D: Incorrect because "3 7He" is not a valid representation of any isotope of helium. The numbers should follow the format A ZX, where A is the total number of nucleons and Z is the atomic number.

Q143. The half-life T of a radioactive element is that period in which _ of the atoms decay.

A. Nine times
B. Double
C. Half✓
D. 4 times
E. 7 times

Explanation: The half-life of a radioactive isotope is the amount of time it takes for one half of the radioactive isotope to decay.So the correct option is C.

Why the other options are wrong

A. Option A: Incorrect. The half-life is the time it takes for half of the radioactive atoms to decay, not nine times the decay period.
B. Option B: Incorrect. The half-life is not double the decay period; it is the time for half the atoms to decay.
D. Option D: Incorrect. The half-life is not four times the decay period; it is the time for half the atoms to decay.
E. Option E: Incorrect. The half-life is not seven times the decay period; it is the time for half the atoms to decay.

Q144. Fluorescence is the property of absorbing radiant energy of …... frequency and re-emitting energy of _ frequency in the visible region of electromagnetic spectrum.

A. low ... high
B. high ... low✓
C. low ... low
D. high ... high

Explanation: In fluorescence, a photon is absorbed which takes an atom or molecule to a higher energy level. To conserve momentum, this higher level of energy might consist of a combination of electronic transition, rotational transition, vibrational transition, and kinetic energy. The atom or molecule may remain in a higher energy state for a long enough period of time to collide with other atoms or molecules and transfer some of the energy to them. When a photon of lower energy is emitted, the remaining energy may also be emitted as a photon, but it is unlikely that the energy and momentum can both be conserved, so much of the time the energy remains in the molecule until a collision happens to exchange the energy by means of a collision. Eventually, a low-energy photon is emitted, but by then some of the energy has become part of the internal energy of the material, raising its temperature ever so slightly. So, some energy is released as a second photon and some of the energy contributes to heating up the fluorescent material.

Q145. A reaction in which a heavy nucleus like that of uranium splits up into two nuclei of roughly equal size along with the emission of energy during the reaction is called a:

A. Fission reaction✓
B. Fusion reaction
C. Counter reaction
D. Chemical reaction

Explanation: Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay.So the correct option is A.

Why the other options are wrong

B. Nuclear Fusion reactions power the Sun and other stars. In a fusion reaction, two light nuclei merge to form a single heavier nucleus.
C. A reaction in response or opposition to the main reaction. This situation … is inherently unstable and was bound to produce a counterreaction.
D. A Chemical Reaction is a process that occurs when two or more molecules interact to form a new product(s).

Q146. Identify the main type(s) of nuclear reactors:

A. Slow reactors
B. Fast reactors
C. Thermal reactors
D. All of these✓

Explanation: This option encompasses both slow (thermal) and fast reactors, as they represent the all broad categories of nuclear reactors.

Why the other options are wrong

A. These reactors use slow neutrons to sustain the nuclear fission process. They are generally thermal reactors, relying on moderators to slow down the neutrons. An example is the light-water reactor
B. These reactors use fast neutrons, which do not require a moderator. They are typically used for breeding fuel (creating more fissile material). Examples include sodium-cooled fast reactors.
C. These reactors use slow neutrons, where the fission process is sustained by thermal neutrons that are moderated by substances like water or graphite.

Q147. What is the average translational kinetic energy of molecules in a gas at temperature 27°C?

A. 3.23 x 10-21 J
B. 4.11 x 10-21 J
C. 6.21 × 10-21 J✓
D. 7.71 x 10-21 J
E. 9.11 x 10-21 J

Explanation: The average translational kinetic energy of molecules in a gas is given by the formula: K.E. = (3/2) kTWhere K.E. is the average translational kinetic energy, k is the Boltzmann constant (approximately 1.38 x 10^-23 J/K), and T is the temperature in Kelvin.The given temperature is 27°C, which must be converted to Kelvin by adding 273.15:T = 27°C + 273.15 = 300.15 KSubstituting these values into the formula gives:K.E. = (3/2) * (1.38 x 10^-23 J/K) * (300.15 K)= 6.21 x 10-21 JTherefore, the correct answer is 6.21 x 10-21 J. The other options result from errors in calculation or incorrect conversions.

Why the other options are wrong

A. This option is incorrect. Ensure you have used the correct formula and temperature in Kelvin.
B. This option is incorrect. Double-check your calculations and ensure the temperature is converted to Kelvin.
D. This option is incorrect. Review the formula and ensure all constants and conversion steps are applied correctly.
E. This option is incorrect. Verify your use of the correct formula and conversion to Kelvin.

Q148. She was feeling _ even after five hours of the surgery.

A. Mumbled
B. Haggard✓
C. Pally
D. Grope

Explanation: 'Haggard' means looking exhausted and unwell, especially from fatigue, worry, or suffering. So, the correct sentence is, "She was feeling haggard even after five hours of the surgery."

Why the other options are wrong

A. This option is not correct because 'mumbled' means to say something indistinctly and quietly, making it difficult for others to hear.
C. This option is also incorrect because 'pally' means having a close, friendly relationship.
D. This option is also incorrect because 'grope' means to search blindly or uncertainly by feeling with the hands.

Q149. Utilization of the products of digestion for production of energy or synthesis of cellular material is termed as:

A. Egestion
B. Ingestion
C. Absorption
D. Assimilation✓

Explanation: Assimilation is the process by which the absorbed nutrients are used to produce energy or build new cells.

Why the other options are wrong

A. Egestion refers to the elimination of undigested matter from the body, not the use of digestion products for energy or synthesis.
B. Ingestion involves the intake of complex food, which is the initial step of the digestive process, not the use of digestive products.
C. Absorption is the uptake of diffusible food molecules from the digestive region into the bloodstream, preceding the utilization phase.

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