Pk Mdcat Mock 5 — Solved Past Paper with Answers

Q1. Neither they nor their friend _ solved the question.

• A. Has✓
• B. Have
• C. Was
• D. Were

Explanation: In 'neither-nor' constructions, the verb agrees with the subject closest to it. In this sentence, the subjects are 'they' and 'their friend.' Since 'friend' is closest to the verb and is singular, the verb 'has' is the correct choice, as it aligns with the singular subject. The option 'have' is incorrect as it would require a plural subject. 'Was' and 'were' are incorrect as they do not fit the present tense context.

Q2. She was feeling _ even after five hours of the surgery.

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

Explanation: 'Mumbled' means to say something indistinctly and quietly, making it difficult for others to hear. 'Haggard' means looking exhausted and unwell, especially from fatigue, worry, or suffering. 'Pally' means having a close, friendly relationship. 'Grope' means to search blindly or uncertainly by feeling with the hands.

Q3. Identify errors in sentences:

• A. Neither the men who are listed as administrators nor the woman who is also listed has been appointed to the board.✓
• B. Neither the men who are listed as administrators nor the woman who is also listed have been appointed to the board.
• C. Neither the men who are listed as administrators nor the women who are also listed has been appointed to the board.
• D. Neither the men who is listed as administrators nor has the woman who is also listed been appointed to the board.

Explanation: When the subjects joined by or, nor, either ........ or, neither .........nor are of different persons, the verb agrees with the nearer.

Q4. Spot the error.If you lend him a book, he will lend it to someone else and never you will get it back.

• A. If you lend him a book
• B. He will lend it
• C. To someone else
• D. And never you will get it back✓

Explanation: Adverbs are placed after auxiliary verbs which include “will”. Hence, the correct option is "option D".

Q5. Choose the right option to complete the following sentence:The plot of this story is so _ that I can predict the outcome.

• A. Intricate
• B. Pivotal
• C. Trite✓
• D. Fictitious

Explanation: The purpose of this sentence is to show the plot is very basic and repetitive. Trite will be the best word here as it refers to lacking originality, and something being dull due to overuse.

Q6. Select the nearest correct meaning of the word given.Invidious

• A. Unbreakable
• B. Interesting
• C. Unpleasant✓
• D. Fair

Explanation: "Invidious" means (of an action or situation) likely to arouse or incur resentment or anger in others. This is closest in meaning to "unpleasant" which refers to causing discomfort, unhappiness, or revulsion; disagreeable (something that is likely to arouse or incur resentment or anger in others).

Q7. His credulous nature often landed him in trouble.What does 'credulous' mean over here?

• A. Dreamy
• B. Naughty
• C. Innocent
• D. Willing to believe easily✓

Explanation: Credulous means being very naive, gullible, and innocent hence, having or showing too great a readiness to believe things. The correct meaning of "credulous" in the given context is option D) "Willing to believe easily." When describing someone as credulous, it means that they are prone to accepting things as true without questioning or doubting them. Consequently, their trusting and gullible nature can lead them into difficulties or problematic situations.

Q8. Choose the correct passive voice:How did she defraud him of his savings?

• A. How had he been defrauded of his savings?
• B. How had he been defrauded by her?
• C. How was he defrauded of his savings?✓
• D. How was he defrauded by her of his savings?

Explanation: This option correctly transforms the sentence into the passive voice by using the verb “was defrauded” indicating the action being done to the subject “he”. The prepositional phrase “of his savings” remains intact as it represents what was taken from him.

Q9. Read the passage. Then answer the questions below.Mona doesn’t like to ask people for help. But it is hard for her to perform daily activities on her own. She is almost 13, yet she is no larger than a 5-year-old. Mona has trouble keeping her balance and can’t walk very far. When she uses a wheelchair, she can’t push it herself.Fortunately, Mona has a wonderful service dog named Sam. A service dog is a dog that has been trained to assist someone who has a physical problem. Sam lets Mona lean on him when she walks. He also pulls her wheelchair and turns lights on and off. When Mona dropssomething, Sam picks it up. He even pulls her socks off at night. Sam also helps Mona with everyday tasks at school. He carries her books from class to class in a special backpack. He puts Mona’s completed assignments in her teachers’ homework trays. In the lunchroom he throws away her trash.Besides making Mona less dependent on other people, Sam helps her lead a fuller life.Mona’s classmates flock around Sam like geese. This has helped her make friends. Sam also helps Mona be more active. With his aid, she raised over $500 in a walk-a-thon for her local humane society. Because of Sam, Mona doesn’t have to ask people for help. Sam brings her closer to other kids. And he even helps her contribute to her community.In the passage, the author writes, “Mona’s classmates flock around Sam like geese.” Which of the following literary techniques is used in this sentence?

• A. Allusion, characterized by a reference to, or representation of, people, places, events, literary work, myths, or works of art, either directly or by implication
• B. Personification, characterized by giving human traits to nonhuman things, such as animals or objects
• C. Irony, characterized by the use of words to express the opposite of their usual meaning
• D. Simile, characterized by the making of a comparison using the words “like” or “as”✓

Explanation: The literary technique used in the sentence "Mona’s classmates flock around Sam like geese" is simile.A simile is a figure of speech that directly compares two different things using the words "like" or "as" to highlight a similarity between them. In this case, the author is comparing Mona's classmates gathering around Sam to the way geese gather together, emphasizing the large and interested group of classmates surrounding the service dog.

Q10. 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.

Q11. Read the following passage to answer the given question;The fact that we were all as safe as kittens under a cook-stove did not, however, assuage in the least the fine despair and the grotesque desperation which seized upon the residents of the East Side when the cry spread like a grass fire that the dam had given way. Some of the most dignified, staid, cynical, and clear thinking men in town abandoned their wives, stenographers, homes, and offices and ran east. There are few alarms in the world more terrifying than 'The dam has broken!' There are few persons capable of stopping to reason when that clarion cry strikes upon their ears, even persons who live in towns no nearer than five hundred miles to a dam.The phrase "spread like a grass fire" means

• A. Rapid spread✓
• B. Firefighting
• C. Grass growth
• D. Dreadful sight
• E. Hidden news

Explanation: The phrase 'spread like a grass fire' is a metaphor used to describe something that spreads very quickly and widely, akin to how a fire can rapidly move through dry grass. In the passage, it illustrates the swift dissemination of panic among the residents.

Q12. Demonstrate correct use of articles and prepositions to clarify meaning:I advised her _ drink it.

• A. Don't
• B. Not to✓
• C. To not
• D. To don't

Explanation: A preposition must be placed before the adverb. Hence, the correct option is option B.

Q13. Read the passage. Then answer the questions below.Mona doesn’t like to ask people for help. But it is hard for her to perform daily activities on her own. She is almost 13, yet she is no larger than a 5-year-old. Mona has trouble keeping her balance and can’t walk very far. When she uses a wheelchair, she can’t push it herself.Fortunately, Mona has a wonderful service dog named Sam. A service dog is a dog that has been trained to assist someone who has a physical problem. Sam lets Mona lean on him when she walks. He also pulls her wheelchair and turns lights on and off. When Mona drops something, Sam picks it up. He even pulls her socks off at night.Sam also helps Mona with everyday tasks at school. He carries her books from class to class in a special backpack. He puts Mona’s completed assignments in her teachers’ homework trays. In the lunchroom he throws away her trash.Besides making Mona less dependent on other people, Sam helps her lead a fuller life.Mona’s classmates flock around Sam like geese. This has helped her make friends. Sam also helps Mona be more active. With his aid, she raised over $500 in a walk-a-thon for her local humane society.Because of Sam, Mona doesn’t have to ask people for help. Sam brings her closer to other kids. And he even helps her contribute to her community.Which of the following would be the best title for this passage?

• A. Why Mona Loses Her Balance
• B. How Mona’s Service Dog Helps Her✓
• C. Raising Money for the Humane Society
• D. Why Mona is dependent

Explanation: The best title for this passage would be:"How Mona’s Service Dog Helps Her"This title encapsulates the central theme of the passage, which revolves around the role of Sam, the service dog, in assisting Mona with various daily activities and enhancing her life in multiple ways, including social interactions and community involvement.

Q14. Answer on passage:The high school math department needs to appoint a new chairperson, which will be based on seniority. Ms. West has less seniority than Mr. Temple, but more than Ms. Brody. Mr. Rhodes has more seniority than Ms. West, but less than Mr. Temple. Mr. Temple doesn't want the job. Who will be the new math department chairperson?

• A. Mr. Rhodes✓
• B. Mr. Temple
• C. Ms. West
• D. Mr. Brody

Explanation: Mr. Temple has the most seniority, but he does not want the job. Next in line is Mr. Rhodes, who has more seniority than Ms. West or Ms. Brody.

Q15. Read the passage to answer the question:What is life? A little scum of no importance on the surface of an unimportant globe circling round a second-rate star? An accidental conglomeration of atoms which have come together by an odd chance, the result of an exceedingly improbable happening? That is what some astronomers would have us think. Looking out into the depth of space, they have discovered a universe of unthinkable dimensions. A billion suns in our own galaxy, beyond it perhaps abillion galaxies, only revealed to us as tiny smudges on aphotographic plate. No wonder they are impressed by the enormous disparity between the scaffolding and the result. Life seemed to be, as Jeans said, ‘an utterly unimportant by-product’ in a universe which was clearly not designed for life, and which, to all appearances, is either totally indifferent or definitely hostile to it’. It seemed ‘incredible that the universe can have been designed primarily to produce life like our own; had it been so, surely we have might expected to find a a better proportion between the magnitude of the mechanism and the amount of the product. The title of the passage can be:

• A. Gathering of atoms
• B. The life outside the earth
• C. Universe and it's unneeded vastness
• D. Life versus universe✓

Explanation: In this passage, the author can be seen talking about the majesty of the universe with respect to the existence of “life” in various respects. Hence the best title to this will be Life Versus Universe.

Q16. 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.

Q17. Given figures shows:

• A. Structure of Lenticel✓
• B. Hydathode showing gaseous vapour exchange
• C. Fungus reproducing by spore formation
• D. Algae reproducing by spore formation

Explanation: The figure shows the structure of 'Lenticel', which facilitates gaseous exchange and transpiration. These are aerating pores in the bark of woody trees. These are surrounded by loosely arranged thin walled complementary cells, enclosing intercellular spaces for gaseous exchange.

Q18. Four words are shown below:Branchioceranthus - sexual reproduction - nutritive - HydraThese words can be used in the spaces P, Q, R, and S to complete the sentence below:The coelenterates range in size from microscopic _P_ to macroscopic, _Q_, a hydrozoan polyp that may reach two meters in length. Cnidarians are found in two basic forms: the polyps and the medusae. Polyps are cylindrical animals, which in most cases are _R_ in function, hence named as gastrozooids. The medusae are umbrella-like in form. These are free-swimming. The medusae are involved in _S_ as they have gonads.

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

Explanation: Branchioceranthus is macroscopic and hydra is microscopic. P = Hydra Q =Branchioceranthus R = nutritive S= Sexual reproduction

Q19. If lipopolysaccharides did not appear in the wall of bacteria on staining then it will be known as _.

• A. Gram negative
• B. Gram positive✓
• C. Capsule
• D. Both Gram positive & negative

Explanation: The Gram stain procedure distinguishes between Gram positive and Gram negative groups by coloring these cells red or violet. Gram positive bacteria stain violet due to the presence of a thick layer of peptidoglycan in their cell walls, which retains the crystal violet these cells are stained with. Alternatively, Gram negative bacteria stain pink, which is attributed to a thinner peptidoglycan wall, which does not retain the crystal violet during the decoloring process.Gram-positive bacteria do not contain lipopolysaccharides, but carry surface teichoic acids, lipoteichoic acids and peptidoglycan instead.The outer membrane of Gram-negative bacteria contains lipopolysaccharides, proteins, and phospholipids.The bacterial capsule is a large structure of many bacteria. It is a polysaccharide layer that lies outside the cell envelope, and is thus deemed part of the outer envelope of a bacterial cell.

Q20. Spirochete is an example of which type of bacteria?

• A. Aerobic
• B. Facultative
• C. Anaerobic✓
• D. Both Options A and B are correct

Explanation: Spirochete are free-living non-pathogenic inhabitants of mud and water, typically thriving in anaerobic (oxygen-deprived) environments.

Q21. If more substrate is added to an already occurring enzymatic reaction, and more enzyme activity is seen, then this is because of which of the following?

• A. There is probably more substrate present than there is enzyme
• B. There is probably more product present than there is either substrate or enzyme
• C. The enzyme substrate complex is probably failing to form during the reaction
• D. There is probably more enzyme available than there is substrate✓

Explanation: When more substrate is added to already occurring enzymatic reaction and it is seen that activity has been increased this means that there are more enzyme available than substrate so that new added substrates make enzyme substrate complex with the available extra enzymes.OPTION A: If there is more substrate than there are enzymes than the product formation ceases and activity of enzyme decreases.OPTION B: It is not possible.OPTION C: One substrate, one enzyme forms one substrate complex and if more substrate is present than this complex fails to be formed.OPTION D: If more enzyme is available than substrate this means that there are more enzyme available than substrate so that new added substrates make enzyme substrate complex with the available extra enzymes.

Q22. Under the microscope, the bacteria appear a bluish-purple color. Which class of bacteria are on the slide?

• A. Helix
• B. Around
• C. Rod✓
• D. Rigid helix

Explanation: c) Rod: The correct answer is option (c) "Rod." Rod-shaped bacteria are also known as bacilli. They have a cylindrical or rod-like shape. When stained using the Gram stain technique, some rod-shaped bacteria appear bluish-purple under the microscope. The color is a result of the Gram stain's interaction with the bacterial cell wall, which helps in the classification of bacteria based on their cell wall composition.

Q23. Booklungs serve the function of respiration in:

• A. Scorpion✓
• B. Earthworm
• C. Frog
• D. Cockroaches

Explanation: A book lung is a type of respiration organ used for atmospheric gas exchange that is present in many arachnids, such as scorpions and spiders. Each of these organs is located inside an open ventral abdominal, air-filled cavity (atrium) and connects with the surroundings through a small opening for the purpose of respiration.

Q24. The first viral disease namely _ was discovered in 1892.

• A. Hepatitis
• B. AIDS
• C. Rabies
• D. Tobacco mosaic disease✓

Explanation: Tobacco mosaic disease, caused by the tobacco mosaic virus, infects plants. It causes the leaves to become wrinkled, discolored, and mottled. It was discovered by Dmitry Ivanowsky.

Q25. The only promoter of leaf senescence among the following plant hormones is:

• A. Gibberellins
• B. Cytokinins
• C. Auxins
• D. Abscisic acid✓

Explanation: Abscisic acid promotes senescence.

Q26. Find the mass in grams of 1.69 mol of phosphoric acid:

• A. 165.6 g✓
• B. 157 g
• C. 148 g
• D. 138 g

Explanation: Moles = Mass / molar mass Moles x molar mass = mass in grams Molar mass of phosphoric acid H₃PO₄ = 98 g / mol 1.69 mol x 98 g /mol = mass in grams Mass = 165.6 g

Q27. The expression for the radius of the nth orbit of a hydrogen atom was derived by:

• A. Planks
• B. Bohr✓
• C. Rutherford
• D. Einstein

Explanation: The expression for the radius of the nth orbit of a hydrogen atom was derived by Bohr. According to Bohr's theory of the hydrogen atom, Bohr was able to derive the formula for the hydrogen spectrum using basic physics.

Q28. Which of the following catalysts is used in the industrial preparation of methanol?

• A. Zinc oxide and alumina
• B. Alumina and silica
• C. Silica and Chromium oxide
• D. Zinc oxide and Chromium oxide✓

Explanation: The catalyst used in the industrial preparation of methanol is zinc oxide and chromium oxide. This mixture of catalysts is known as **the ** Raschig process. The Raschig process is a catalytic reduction of carbon monoxide to methanol. The reaction is carried out at high temperatures (573-673 K) and pressures (25-35 atm) in the presence of a catalyst. The catalyst promotes the reaction by providing a surface for the reactants to adsorb on and by lowering the activation energy of the reaction.

Q29. What is the unit of slope obtained from Arrhenius equation?(slope=-Ea/2.303R)

• A. K¯
• B. J/mol K
• C. K✓
• D. Mol/K

Explanation: The slope is given by -Ea/2.303R. The units for activation energy or Ea are Jmol−1 and those for R are JK−1mol−1. By dividing Ea by R, K is obtained which is the unit of the slope.

Q30. Rate = K [N2O5 ] has _ of reaction.

• A. First order✓
• B. Pseudo first order
• C. Second order
• D. Third order
• E. Pseudo order

Explanation: The order of the reaction is the sum of all the exponents of reactants in the rate equation. Since the sum of exponents of reactants in this equation is 1. The order of reaction, in this case, is equal to 1.

Q31. What is the major product of the nitration reaction below?

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

Explanation: Since, NO2 is a meta-directing group, the incoming NO2 group would go on meta position. SInce, there is already one NO2 group at postion 3, so the second NO2 group will go on position 5.

Q32. Which of the following have the same number of molecules?

• A. 200 cm2 of Carbon dioxide and 500 cm2 of oxygen
• B. 300 cm2 of Carbon dioxide and 150 cm2 of oxygen
• C. 300 cm2 of Carbon dioxide and 150 cm2 of oxygen
• D. 300 cm2 of Carbon dioxide and 300 cm2 of oxygen✓

Explanation: 300 cm2 of Carbon dioxide and 300 cm2 of oxygen would have the same number of molecules since the number of moles in question is equal, thus the number of molecules would also be the same.

Q33. One Calorie is equal to:

• A. 4.18 kJ
• B. 4.18 J✓
• C. 0.418 KJ mol-1
• D. 0.418 KJ

Explanation: 1 calorie equals 4.18 J. It is very often confused with 1 kcal, which equals to 4.18 kJ

Q34. Which step should be repeated over and over to get a variety of substituted products?

• A. None of these
• B. Termination
• C. Propagation✓
• D. Initiation

Explanation: Radical chain reactions have three distinct phases: initiation, propagation, and termination. The initiation phase describes the step that initially creates a radical species. The propagation phase describes the ‘chain’ part of chain reactions. Once a reactive free radical is generated, it can react with stable molecules to form new free radicals. These new free radicals go on to generate yet more free radicals, and so on. This step, therefore, gives a variety of substituted products. The termination phase occurs when two free radical species react with each other to form a stable, non-radical adduct.

Q35. During oxidation of unsymmetrical ketones which atom is oxidized?

• A. Carbonyl carbon
• B. Carbon attached to smaller number of hydrogen atom✓
• C. Carbon attach to larger number of hydrogen atoms
• D. Hydrogen

Explanation: The oxidation of unsymmetrical ketones involves the cleavage of the carbon-carbon bond adjacent to the carbonyl group. The carbon atom that is attached to fewer hydrogen atoms is more electron deficient and therefore more susceptible to oxidation. This carbon atom is oxidized, and the other carbon atom is reduced. The result is the formation of two different carboxylic acids.

Q36. If the lowest energy X-rays have λ = 4.0 x 10-8 m , estimating the minimum difference in energy between two Bohr orbit, where an electronic transition would correspond to the emission of an X-ray, at what minimum Z (atomic number) would a transition from the second energy level to the first result in the emission of an X-ray?

• A. Z=2✓
• B. Z=3
• C. Z=4
• D. Z=5

Explanation: The energy of a photon emitted during a transition between two energy levels in a Bohr atom is given by the equation: △E = λhc = 6.63×10-34 J·s × 3.00×108 m/s / 4.0×10-8 m = 4.97×10-15 J. For a hydrogen-like ion, the energy difference between levels n=2 and n=1 is △E = 13.6 eV × Z2 × (1/n12 - 1/n22), where n1 = 1 and n2 = 2. Calculating for Z=2 gives the energy close to the X-ray energy calculated, thus confirming helium (Z=2) as correct. For higher Z values, the energy difference exceeds the given X-ray energy, eliminating options B, C, and D.

Q37. If a graph is plotted between pressure on x- axis and volume on y- axis for Boyle's law verification, the curve obtained is called

• A. Pseudotherm
• B. Isotherm✓
• C. Biotherm
• D. All of these

Explanation: If a graph is outlined in between pressure on the x-axis (abscissa) and volume on the y-axis (ordinate), then a curve is obtained. This curve is called isotherm 'iso' implies the same, “therm” implies heat.

Q38. This is is a structure of

• A. Menadione✓
• B. 𝛂 - Tocopherol
• C. Calciferol
• D. Thiamine
• E. Pyridoxine

Explanation: The above structure is of Menadione.

Q39. Formation of Hydrogen molecule according to VBT theory involves overlap of:

• A. 1s orbital✓
• B. 2s orbital
• C. 2p orbital
• D. 2px orbital

Explanation: Valence bond theory describes bonding as a consequence of the overlap of two separate atomic orbitals on different atoms that creates a region with one pair of electrons shared between the two atoms. It involves 1s orbital because unpaired orbitals in the valence shells of two adjoining atoms can combine to form a chemical bond if they overlap significantly.

Q40. The unit cell parameters of the monoclinic system are:

• A. a=b≠c ; α=β=γ=90
• B. a≠b≠c ; α=γ=90 ; β≠90✓
• C. a≠b=c ; α=β=90; γ≠90
• D. a=b=c ; α=β=γ=90

Explanation: The monoclinic crystal system is characterized by three unequal axes, with two of them being perpendicular (α=γ=90°) and the third angle (β) differing from 90°. This distinguishes the monoclinic system from others where either all axes are equal or all angles are right angles. Option B correctly represents this with a≠b≠c ; α=γ=90° ; β≠90°. Options A, C, and D describe tetragonal, orthorhombic, and cubic systems, respectively, which do not fit the monoclinic parameters.

Q41. Which one among the following is the strongest reducing agent:Fe2+ + 2e -> Fe (-0.44V)Sn2+ + 2e -> Sn (-0.14 V)Ni2+ + 2e -> Ni (0.25 V)Fe3+ + e -> Fe2+ (-0.77 V)

• A. Fe3+
• B. Ni2+
• C. Fe2+✓
• D. Sn2+

Explanation: The half-reaction for Fe²⁺ to Fe has a reduction potential of -0.44 V. A more negative reduction potential indicates that Fe²⁺ is a stronger reducing agent, meaning it is more readily oxidized. Therefore, Fe²⁺ is the strongest reducing agent among the options provided.

Q42. The strength of an acid depends on?

• A. Ease of removal of proton
• B. Stability of the anion formed
• C. Stability of the cation formed
• D. Depends on both ease of removal of proton and stability of the anion formed✓

Explanation: The correct option is: Depends on both ease of removal of a proton and stability of the anion formed.Explanation:The strength of an acid is determined by its ability to donate a proton (H+) in a chemical reaction. This is often represented by the equation:Acid (AH) ⇌ H+ + Anion (A-)In this equation, the acid (AH) donates a proton (H+) to form the conjugate base or anion (A-). The strength of an acid is influenced by two main factors:Ease of removal of a proton: The more readily an acid can donate a proton, the stronger it is. Acids with weak bonds between hydrogen and the rest of the molecule are more likely to lose the proton and, thus, are stronger acids.Stability of the anion formed: After the acid donates its proton, the resulting anion (conjugate base) is formed. A stable anion is better able to handle the negative charge that results from gaining an electron. An unstable or highly reactive anion will make the acid weaker.Together, these factors play a crucial role in determining the strength of an acid. Acids with both a high tendency to release protons (ease of removal of a proton) and produce stable anions are considered strong acids. On the other hand, weak acids have a lower tendency to donate protons and/or form less stable anions.In summary, the strength of an acid depends on both the ease of removal of a proton and the stability of the anion formed after the proton donation.

Q43. Which of following has "higher boiling"and "melting point"?

• A. Acetone
• B. 2 - Butanol✓
• C. Propane
• D. 2 - Methylpropene

Explanation: OPTION A: Acetone has a boiling point of 56.5°C and a melting point of -94.9°C. It is a relatively small molecule and lacks the ability to form hydrogen bonds, resulting in weaker intermolecular forces.OPTION B: 2-butanol has a higher molecular size and the presence of an -OH group, allowing for intermolecular hydrogen bonding. Hydrogen bonding leads to stronger intermolecular forces, resulting in higher boiling and melting points. 2-butanol has a boiling point of 99.5°C and a melting point of -114.5°C.Hence, B is the correct option.OPTION C: Propane (C3H8) is a small molecule with weak London dispersion forces between its nonpolar molecules. It has a boiling point of -42.1°C and a melting point of -187.7°C.OPTION D: 2-methyl propene (also known as isobutylene) (C4H8) is also a small molecule with weak intermolecular forces. It has a boiling point of -6.9°C and a melting point of -159.7°C.

Q44. If the e/m value of electron is 1.7588 x 1011 C/kg, then what would be the mass of electron in grams (charge on electron is 1.6022 x 10-19 coulombs)?

• A. 9.1095 x 10-31 g
• B. 91.095 x 10-31 g
• C. 9.1095 x 10-28 g✓
• D. 0.919095 x 10-33 g

Explanation: If e/m is equal to 1.7588x10^11 and the charge on an electron is 1.6 x10^-19 then the mass can be calculated as: 1.7588x10^11=1.6x10^-19/m m-9.109 x 10^-31kg. In g, 9.1x10^-28 g As it is numerical, it can have only one possible answer.

Q45. The molecular structure of a hydrocarbon is shown below.

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

Explanation: B is a structural isomer of the structure shown above. Structure in A is the same as the structure shown. Structure C is not an isomer because it does not have the same number of carbon and hydrogen atoms as in the diagram shown. Structure D has a double bond that reduces two hydrogen atoms from it as compared to the structure shown that is why D can not also be an isomer of the diagram shown above.

Q46. A photon of wavelength 12.7 x 1015 m is emitted when it jumps from higher to n = 1, what will be a higher orbit?

• A. n = 2
• B. n = 3
• C. n = 4✓
• D. n = 5

Explanation: Option A is wrong because n=2 will not be the higher orbit. Option B is wrong because n=3 will not be the higher orbit. Option: C Rydberg's Formula: Rydberg's Formula, 1 λ = Rh ( 1/n21 − 1/n22), relates the wavelength of a photon emitted or absorbed by an electron transition.

Q47. The compression factor (compressibility factor) for one mole of a Van der Waals gas at 00 C and 100 atmosphere pressure is found to be 0.5. Assuming that the volume of the gas molecule is negligible, calculate the Van der Waals constant 'a'.

• A. 1.254✓
• B. 2.87
• C. 3.76
• D. 1.34

Explanation: This is the following solution.

Q48. A diabetic person’s exhaled breath contains propanone. A student tries to test the diabetes by asking the person to bubble the reagent with his exhaled breath. Which of the following reagents would give a positive result?

• A. Aqueous Bromine
• B. Fehling’s reagent
• C. Tollen’s reagent
• D. Alkaline aqueous iodine✓

Explanation: Propanone contains the R-CO-CH3 group hence it gives a positive triiodomethane or iodoform test. Iodoform test is used to check the presence of carbonyl compounds with the structure R-CO-CH3 or alcohols with the structure R-CH(OH)-CH3 in a given unknown substance. The reaction of iodine, a base, and a methyl ketone gives a yellow precipitate along with an “antiseptic” smell.

Q49. Born Haber cycle is used to determine:

• A. Electron affinity
• B. Lattice energy✓
• C. Crystal energy
• D. Both B and C

Explanation: The Born-Haber cycle is a thermochemical cycle that allows us to calculate the lattice energy of an ionic compound by considering the various energy changes involved in its formation. It uses Hess's Law to sum the enthalpy changes for individual steps, including ionization energy and electron affinity. Option A, 'Electron affinity,' while related to the cycle, does not represent the main purpose of the Born-Haber cycle, which focuses on lattice energy. Option C, 'Crystal energy,' is not a recognized term and does not apply, making it incorrect. Option D is also incorrect as it includes the invalid term 'crystal energy.' Thus, the correct and most relevant answer is Option B, 'Lattice energy,' as it directly corresponds to the primary purpose of the Born-Haber cycle.

Q50. Which of the following compounds possesses a single covalent bond between carbon and hydrogen?

• A. CH4
• B. C2H2
• C. C2H4
• D. All of the above✓

Explanation: All of the compounds contain a single covalent bond between carbon and hydrogen atoms. Only that C2H2 and C2H4 contain triple and double bonds between carbon atoms respectively.

Q51. Which of the following reactions is used for the production of alcohols on industrial scale?

• A. Hydrogenation of alkenes
• B. Hydration of alkenes✓
• C. Hydrohalogenation of alkenes
• D. Hydroxylation of alkenes

Explanation: Option A describes a reaction that produces alkanes from alkenes.Option B describes a reaction that produces alcohol from alkenes so, it is correct.Option C describes a reaction that produces alkyl halides from alkenes.Option D describes a reaction that produces glycol from alkenes, which is a type of alcohol but not the type that is produced on an industrial scale for commercial use.

Q52. Paramagnetic behaviour of transition elements is due to the presence of:

• A. s electrons
• B. Unpaired electrons✓
• C. Paired electrons
• D. Outer d electrons

Explanation: Option B is correct as paramagnetism (the ability of a material to be weakly attracted to a magnet due to its magnetic field, which induces an internal magnetic field of the material) is caused by the presence of "unpaired electrons", with each electron having a magnetic moment associated with its spin angular momentum and orbital angular momentum.

Q53. A 4s orbital has:

• A. One node
• B. Two nodes
• C. three nodes✓
• D. O nodes

Explanation: 4s orbital has 3 radial nodes plus 0 angular nodes

Q54. The flavour of amyl butyrate is:

• A. Mango
• B. Raspberry
• C. Apricot✓
• D. Orange

Explanation: c) Apricot: Amyl butyrate is often used to impart an apricot-like aroma and flavor. Therefore, the flavor of amyl butyrate can be described as apricot-like.

Q55. The IUPAC name of the following compound is:

• A. 1-Ethyl-2, 4-dimethlycyclohexane✓
• B. 2-Ethyl-1,4-dimethylcyclohexene
• C. 2-Ethyl-1, 1-dimethylcyclohexane
• D. 4-Ethyl-1, 2-dimethylcyclohexane

Explanation: The IUPAC name of the compound is 1-ethyl-2,4-dimethylcyclohexane. The parent compound is cyclohexane. The carbon to which ethyl is attached is considered carbon 1 according to alphabetical order. The two methyl groups are on carbon 2 and 4 respectively.

Q56. The cation that distort the electron cloud of NO3− ion more and facilitates its decomposition is:

• A. Li+
• B. Mg2+
• C. Cs+
• D. Be2+✓

Explanation: Polarizability refers to the ability of a cation to distort the electron cloud of an anion in an ionic compound and the anionic cloud is pulled towards the cation when it gets distorted. According to Fajan’s rule, the greater charge density(charge/size) on a cation leads to greater distortion. Due to higher charge and smaller size, the charge density of Be++ is and so it will distort the electron cloud of NO3- more facilitating its decomposition.

Q57. Enthalpy of a compound is equal to its

• A. Heat of combustion
• B. Heat of formation✓
• C. Heat of solution
• D. Heat of dilution

Explanation: The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, so the answer is B. The enthalpy of combustion of a substance is defined as the heat energy given out when one mole of a substance burns completely in oxygen. The heat of solution also referred to as the enthalpy of solution or enthalpy of dissolution, is the enthalpy change associated with the dissolution of a solute in a solvent heat of dilution, or enthalpy of dilution, refers to the enthalpy change associated with the dilution process of a component in a solution.

Q58. If the total energy of an electron in the first shell of an H-atom is –13.6 eV, then its potential energy in the 1st excited state would be:

• A. +6.8 eV
• B. +20.4 eV
• C. – 6.8 eV✓
• D. +3.4 eV

Explanation: This is the following solution:The energy of an electron in its nth orbit = -13.6/n2. For first excited state n=2 T.E in first excited state = -13.6/4 = -3.4 eV P.E = - 2ke2/r T.E = -ke2/r P.E = 2 (T.E) PE in the first excited state = -6.8 eV.

Q59. A chemical reaction is catalyzed by a catalyst X. Hence, X:

• A. Increases activation energy of the reaction
• B. Does not affect equilibrium constant of the reaction✓
• C. Decreases rate constant of the reaction
• D. Reduces enthalpy of the reaction

Explanation: A catalyst provides an alternative reaction pathway with lower activation energy, increasing the reaction rate. It does not change the energies of reactants or products, so the equilibrium position remains unchanged. Therefore, the correct answer is B .

Q60. Study the following redox reaction and answer the following question:10Clˉ +16H+ + 2MnO4ˉ → 5Cl2 + 2Mn2+ + 8H2O

• A. Manganese is oxidized from +7 to +2
• B. Chlorine ions are reduced from -1 to zero
• C. Chlorine is reduced from 0 to -1
• D. Manganese is reduced from +7 to +2✓

Explanation: The correct change in oxidation numbers

Q61. The rate of a gaseous reaction Is given by K [A] [B]. If the volume of the vessel containing these gases is reduced to 1/4th of the initial volume, the rate of reaction relative to the original rate would be:

• A. 16/1✓
• B. 1/16
• C. 4/1
• D. 1/8
• E. 8/1

Explanation: If the volume of the vessel is reduced by 1/4th that means according to formula C=n/V concentration of each gas in the flask increases by a factor of 4 times. Since concentrations of two gases are increased by this factor that increases the overall rate by 4x4=16.

Q62. On the hydrogen atom spectrum, a series of spectral lines that fall within the visible region is:

• A. Lymen series
• B. Balmer Series✓
• C. Paschen series
• D. Bracket series
• E. Pfund series

Explanation: Lyman series of hydrogen atom lies in ultraviolet region, Balmer series lies in visible region while Pfund and Paschen series lie in infrared region.

Q63. Why is it necessary to distill aldehyde formed from oxidation of primary alcohol through acidified potassium dichromate (VI) solution or acidified sodium dichromate (VI) solution?

• A. Aldehyde formed may be oxidized further to carboxylic acid concerned✓
• B. Aldehyde formed is unstable and decompose back to original precursor i.e. primary alcohol
• C. Aldehyde may be oxidised further to a ketone
• D. Aldehyde formed may react with primary alcohol, the original reactant.

Explanation: Oxidation of alcohols to aldehydes is partial oxidation, if aldehydes are further oxidized they form carboxylic acids. Therefore, the conditions required for making aldehydes are heat and distillation.

Q64. A rotating wheel of radius 0.5 m has an angular velocity of 5 rad/s at some instant and 10 rad / s after 5 s. Find the angular acceleration of a point on its rim.

• A. 1 rad/s2✓
• B. 3 rad/s2
• C. 5 rad/s2
• D. 7 rad/s2
• E. 9 rad/s2

Explanation: The angular acceleration of a rotating object can be found using the formula α = (ωf - ωi) / t, where ωf is the final angular velocity, ωi is the initial angular velocity, and t is the time interval. In this case, the initial angular velocity (ωi) is 5 rad/s, the final angular velocity (ωf) is 10 rad/s, and the time interval (t) is 5 seconds. Substituting these values into the formula gives: α = (10 rad/s - 5 rad/s) / 5 s = 1 rad/s2. Therefore, Option A is correct. All other options are incorrect as they do not result from applying this formula to the given values.

Q65. Doubly ionized atoms 𝑋 and 𝑌 of two different elements are accelerated through the same P.D. on entering a uniform magnetic field they describe circular paths of radii 𝑅1 and 𝑅2. The masses of 𝑋 and 𝑌 are in the ratio of:

• A. R1: 𝑅2
• B. 𝑅2: 𝑅1
• C. R21 : 𝑅22✓
• D. R22: 𝑅21

Explanation: Refer to the following

Q66. Magnetic flux is maximum when the angle, between the area vector and the magnetic field lines, is?

• A. 0°✓
• B. 90°
• C. 120°
• D. All of these

Explanation: Magnetic Flux refers to the number of magnetic field lines, passing through a particular area. The formula, to calculate magnetic flux, is; BA cos(theta), where 'B' is the magnetic flux density, 'A' is the area, and 'theta' is the angle between the two vectors. When theta is zero, which implies that the two quantities are parallel to each other, magnetic flux would be 'BA', which is the maximum amount.

Q67. Moment of inertia of a thin rod of mass m, length l about a line passing through its center is:

• A. ml2
• B. ½ ml2
• C. ⅓ ml2
• D. ⅖ ml2
• E. 1/12 ml2✓

Explanation: Moment of inertia of a thin rod of mass M and length L about an axis passing through its center is 1/12ML2.

Q68. Equations of kinetics are valid only when the acceleration is:

• A. Increasing
• B. Decreasing
• C. Constant✓
• D. Vary with time

Explanation: The equations of kinetics can be utilized for any motion that can be described as being either a constant velocity motion (an acceleration of 0 m/s/s) or a constant acceleration motion. They can never be used over any time period during which the acceleration is changing.○Equations of kinetics are only valid in uniform motion or non- accelerating motion or constant acceleration (a=0).

Q69. To determine the resistance of a voltmeter by discharging a capacitor through it, the instantaneous voltage is then given by the relation:

• A. V(t) = V0e-t/RC✓
• B. V(t) = V0(1 - e-t/RC)
• C. V(t) = V0et/RC
• D. V(t) = V0t/RC

Explanation: Option A is the correct option since Voe-t/RC gives the correct instantaneous voltage.

Q70. The six strings of a guitar are the same length under nearly the same tension, but they have different thicknesses. On which string do waves travel the fastest?

• A. The thickest string
• B. The thinnest string✓
• C. The wave speed is the same on all the strings
• D. None of the above

Explanation: The velocity of a transverse wave in a stretched string is given by: v = √(T/n). Where T is the Tension and n is the mass per unit lenthn = m/L = ρπr^2/L where r is the radius of the wirer = d/2 where d is the diameterSo, v = √ (4T/ρπd^2)v= 2/d √(T/ρπ)As it can be seen, v is inversely proportional to dThus, the velocity of wave is highest for thinnest string.

Q71. A disc, a hoop, and a sphere of the same mass and radius are rolled down from a frictionless, inclined plane. Which has a greater speed on reaching the ground?

• A. Disc
• B. Loop
• C. Sphere✓
• D. All have the same speed

Explanation: The sphere has most of its mass near the axis of rotation, so it will have the smallest moment of inertia and will reach the ground first.The disc has its mass uniformly distributed, so will have a greater moment of inertia and will arrive second.The hoop has all its mass concentrated away from the center, so will have the greatest moment of inertia. It will arrive last, but will then travel farther away on the horizontal plane than the other shapes, as it will have stored more of the original potential energy in the form of rotational energy.

Q72. “The magnitude of electrostatic force between two point charges is directly proportional to the product of the magnitude of the charges and inversely proportional to the square of the distance between them.” This is known as:

• A. Gauss’s Law
• B. Ohm’s Law
• C. Faraday's Law
• D. Newton's Law
• E. Coulomb's Law✓

Explanation: The statement given is a direct description of Coulomb's Law. This law quantitatively defines the electrostatic force between two point charges as F = k(q1*q2)/r², where F is the force, q1 and q2 are the magnitudes of the charges, r is the distance between the charges, and k is Coulomb's constant. This law is fundamental in understanding electrostatic interactions.Other options explain different physical laws: Gauss's Law pertains to electric fields, Ohm's Law to electrical circuits, Faraday's Law to electromagnetic induction, and Newton's Laws to mechanics. None of these describe the electrostatic force between point charges.

Q73. Two resistors R1 and R2 may be connected either in series or in parallel across a battery of zero internal resistance. It is required that the joule heating for parallel combination be five times that for series combination. If R1 = 100Ω, find possible values of R2.

• A. 38.2 Ω✓
• B. 35.3 Ω
• C. 48.2 Ω
• D. None of the above

Explanation: Correct option is 'A'.

Q74. Who stated the right-hand thumb rule?

• A. Oersted
• B. Maxwell
• C. Einstein
• D. Fleming✓

Explanation: The right-hand thumb rule was invented by British physicist John Ambrose Fleming in the late 19th century for use in electromagnetism.

Q75. A cathode ray oscilloscope is displaying an AC signal. If one wave is completed in 2 cm along X- axis and time-base setting is 10 ms/cm, then frequency of AC signal will be:

• A. 100 Hz
• B. 50 Hz✓
• C. 20 Hz
• D. 10 Hz
• E. 200 Hz

Explanation: The distance traveled by the wave along the X-axis in one complete cycle is the wavelength, which is given as 2 cm in the problem. The time-base setting is given as 10 ms/cm, which means that one centimeter along the X-axis represents a time of 10 ms. Therefore, the time taken for one complete cycle is:Time = (2 cm) x (10 ms/cm) = 20 msThe frequency, f, is given by the formula:f = 1/TWhere T is the time taken for one complete cycle. Substituting the value of T, we get:f = 1/20 ms = 50 HzTherefore, the frequency of the AC signal is 50 Hz. The correct answer is B.

Q76. The angular velocity of a rotating disk increases from 2 rad/s to 5 rad/s in 0.5s. What is the disk’s average angular acceleration?

• A. 67 rad/s2
• B. 46 rad/s2
• C. 36 rad/s2
• D. 16 rad/s2
• E. 6 rad/s2✓

Explanation: Average angular acceleration = Rate of change of angular velocity = (Final angular velocity - Initial angular velocity) / Time = (5 rad/s - 2 rad/s) / 0.5 s = 6 rad/s²

Q77. After a certain lapse of time, the fraction of radioactive polonium is found to be 12.5% of the initial quantity. If the half-life of polonium is 138 days, then the duration of time-lapse is _days.

• A. 34.5
• B. 276
• C. 414✓
• D. 125

Explanation: The problem states that the fraction of radioactive polonium remaining is 12.5% of the original amount. Since 12.5% is equivalent to 1/8, we can determine the number of half-lives needed to reach this fraction. Starting from N, after each half-life, the quantity is halved:1. After one half-life (138 days): N/22. After two half-lives (276 days): N/43. After three half-lives (414 days): N/8Thus, three half-lives are required for the quantity to reduce to 12.5% of its original amount, making the duration 414 days.Other options do not correctly match the number of half-lives or the resulting fraction of the remaining quantity.

Q78. Two capacitors C1 (6µF) and C2 (12µF) are in series across a 180 volts D.C supply. Calculate the charges on C1 and C2 respectively.

• A. 120x106 C, -420x106 C
• B. 320x10-6 C, 420x10-6 C
• C. 420x10-6 C, 320x10-6 C
• D. 720x10-6 C, 720x10-6 C✓
• E. 620x10-6 C, 420x10-6 C

Explanation: Charge remains same in series and charges of both capacitors are only same in Option D and so it is the right answer.You can even calculate the charge using this;net capacitance in series:1/C= 1/C1 + 1/C21/C = 1/12 + 1/6 C= 4x10-6 FC=Q/V4x10-6 = Q/180Q= 720 x 10-6 C

Q79. Which of the following is the angle of projection of a projectile if its range is equal to its height?

• A. 48
• B. 60
• C. 90
• D. 76✓

Explanation: This value should be learned for the exam because of the unavailability of calculators during the exam.There is a neat formula for the ratio of height to range:h/r=tanθ/4So whatever angle has a tangent of 4, that’s the angle that sets the ratio of height to range equal to exactly 1.tan−1(4)=75.96°

Q80. A shell of mass m moving with velocity v suddenly breaks into two pieces. The part having mass m/4 remains stationary. The velocity of the other shell will be:

• A. v
• B. 2v
• C. 3v/4
• D. 4v/3✓

Explanation: Using the law conservation of mass, Total momentum Before = Total momentum After Let x be the new speed of remaining mass (3m/4) mv = m1v1 + m2v2 mv = (m/4) (0) + (3m/4) (x) mv = (3m/4) x 4v/3 = x Options A, B and C cannot be derived from the given situation as they donot follow law of conservation of momentum.

Q81. Work done by friction force is always:

• A. Negative
• B. Positive
• C. Zero
• D. Maybe positive, maybe negative, or maybe zero✓

Explanation: The work done by frictional force will be positive when the displacement of the body is in the direction of the force. This can be understood by an example. Consider there are two blocks stacked one over the other. If the lower block starts to move slowly in one direction, then there is a frictional force between the two blocks that prevents the sliding of the two blocks. This force acts on the upper block in the direction of motion of the lower block. The upper block also moves along with the lower block, that is, in the direction of the frictional force. Hence, the work done by friction is positive in this case.The work done by friction can be negative. For example, when a block is sliding over a rough ground, the frictional force acts in a direction opposite to the direction of motion of the block and tries to bring it to a stop. Since, the direction of motion of the block and the direction of frictional force is opposite to each other, the work done by friction is negative.The work done by friction can also be zero. For example, if we try to push a very heavy block on a rough floor, the block does not move. This is because the force of static friction opposes our force. However, since the block does not move, the displacement is zero. Therefore, zero work is done by friction.

Q82. The K.E. of a body of mass 2kg and momentum of 2Ns is:

• A. 1 J✓
• B. 2 J
• C. 3 J
• D. 4 J

Explanation: Given:mass(m)=2kg, momentum(p)=2Nswe know; p=mvv=p/m​v=1ms-1Kinetic energy (K.E)= 1/2(mv2)K.E=1/2(pv) K.E=1/2x(2x1)K.E=1J

Q83. One wheel has a diameter of 30 inches and a second wheel has a diameter of 20 inches. The first wheel travels certain distance revolution in 240 revolutions. In how many revolutions did the second wheel travel the same distance?

• A. 170
• B. 160
• C. 360✓
• D. 420

Explanation: To solve this problem, we need to calculate the circumference of each wheel. The first wheel has a circumference of π × 30 = 30π inches, and the second wheel has a circumference of π × 20 = 20π inches. The ratio of the circumferences is 30π : 20π = 3 : 2. Since the first wheel travels the distance in 240 revolutions, the second wheel, with a circumference ratio of 3 : 2, would travel the same distance in 240 × 3/2 = 360 revolutions. Therefore, option C, 360 revolutions, is the correct answer. The other options provide incorrect calculations based on the same ratio and information given in the question.

Q84. One kilowatt - hour is equivalent to a factor _ in Joules.

• A. 1.2 x 105
• B. 1.2 x 106
• C. 3.6 x 105
• D. 3.6 x 106✓

Explanation: 1 kW =1000J/s 1 h =3600 s ∴ 1 kWh =1000 J/s×3600 s=36×10^5J = 3.6 X 106

Q85. The potential energy of a particle having a mass of 0.5 kg, moving along the x axis, is given by U= 2*x(x-3), where x = the distance moved by the particle. The speed of the particle will be maximum when it has moved a distance of:

• A. 1 m
• B. 1.5 m
• C. 2 m
• D. 3 m✓

Explanation: U = 2*3(3-3) = 0When potential energy is = 0, at that point all the potential energy would have been converted into kinetic energy. Thus when U = 0, K.E = max, and hence speed will be max.

Q86. Mark out the correct option.

• A. The energy of any small part of a string remains constant in a travelling wave
• B. The energy of any small part of a string remains constant in standing wave✓
• C. The energies of all small parts of equal length are equal in a travelling wave
• D. The energies of all small parts of equal length are equal in a travelling wave

Explanation: Option A, C and D are wrong as in a travelling wave energy does not remain constant and is transferred from one point to another.However, in a standing wave as mentioned in option B, Energy of small part remains constant or STANDING in that part.

Q87. Which combination of up (u) and down (d) quarks forms a neutron?

• A. u u u
• B. u u d
• C. u d d✓
• D. d d

Explanation: Quarks are fundamental and elementary particles, there are six flavors of quarks =up, down, top, bottom, charm, and strange.Down, bottom, and strange are the antiparticles of up, top, and charm respectively.Three of these are combined to make any particle such as the proton, neutron, etc.A neutron consists of two down quarks and one up quark.A proton consists of two up quarks and one down quark.Both protons and neutrons are baryons. Baryons are heavy subatomic particles made up of three quarks.

Q88. SI unit of equivalent dose is:

• A. Gray
• B. Radiation
• C. Sievert✓
• D. Rem

Explanation: The SI unit of measure for equivalent dose is the "sievert", defined as one Joule per kg.

Q89. An object whose mass is 100 g starts from rest and moves with constant acceleration of 20 cm/s2. At the end of 8s its momentum in g cm / s is:

• A. 500
• B. 8000
• C. 16,000✓
• D. 33,000
• E. 64,000

Explanation: Step 1:force = mass * accelerationforce = 100 * 20force = 2000 g cm / s2Step 2:change in momentum = force * timechange in momentum = 2000 * 8change in momentum = 16000 g cm/s

Q90. A proton 'up' quark has a charge of:

• A. +2/3✓
• B. -1/3
• C. -2/3
• D. +1/3

Explanation: The two types of sub-atomic particles that you need to know are hadrons and leptons. Particles that are affected by the strong nuclear force are called hadrons, like protons and neutrons. Leptons are particles that are affected by the weak nuclear force, like electrons. Hadrons are made of quarks that can have one of 6 flavors. Two flavors found in a proton are up and down. The quark composition is such that the overall charge of the particle is maintained. In the case of a proton, that charge is +1. Proton: u u d The charge of 'u' is +2 / 3.

Q91. Motional e.m.f induced in a coil is dependent on?

• A. Magnetic field
• B. Orientation
• C. Length
• D. All of these✓

Explanation: The factors on which 'Motional emf' depends are nothing but, the 'magnetic field, velocity, and length of the rod'.

Q92. To generate force of repulsion both the charges must be

• A. Negative
• B. Positive
• C. May be positive or negative✓
• D. Cannot be determined

Explanation: For repulsion both the charges must be same, they can both be either positive or negative.

Q93. Identify the schematic representation of Fission Process from the following options?

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

Explanation: The correct answer is Option A because it correctly depicts the fission process, where a large atomic nucleus splits into two or more smaller nuclei, releasing energy and neutrons. This process does not necessarily result in identical fragments, allowing for variation in the sizes of the resulting nuclei. Options B and C are incorrect because they imply that the fission fragments must be identical, which is not a requirement. Option D is incorrect because it inaccurately states that energy is absorbed in the fission process, whereas energy is, in fact, released.

Q94. The nuclear force is :

• A. Spin independent
• B. Both charge and spin independent
• C. Spin dependent but charge independent✓
• D. Charge dependent

Explanation: The nuclear force is nearly independent of whether the nucleons are neutrons or protons. This property is called charge independence.It depends on whether the spins of the nucleons are parallel or antiparallel and has a noncentral or tensor component.

Q95. Radiation can cause:

• A. leukemia
• B. radiation sickness
• C. skin cancer
• D. gene mutations
• E. all of the above✓

Explanation: Radiation can lead to multiple adverse health effects, including leukemia, radiation sickness, skin cancer, and gene mutations. Each of these outcomes stems from the ability of radiation to damage biological tissues and DNA. Leukemia is linked to radiation's impact on bone marrow, radiation sickness results from acute high-level exposure, skin cancer is associated with UV radiation, and gene mutations can occur due to ionizing radiation disrupting DNA. Therefore, the most comprehensive answer is all of the above, as radiation can indeed cause all these effects.

Q96. Value of current in a short circuit is_

• A. Infinite✓
• B. zero
• C. minimum
• D. maximum

Explanation: Option A is correct since, in a short circuit, there is no resistance to the flow of charges so a large number of charges flow in a very short time. Thus, the current becomes infinite. Option B is incorrect since there is a flow of charges in a short circuit so the current is not zero Option C is incorrect since it states that current will be very less which is not true as current will be large Option D is incorrect as the maximum current can even occur with very low resistance. But when almost zero resistance is provided the current flow becomes infinite.

Q97. In amplitude modulation, what remains the same:

• A. Frequency of the wave✓
• B. Amplitude of the wave
• C. Wavelength of the wave
• D. Intensity of waves

Explanation: In amplitude modulation, the amplitude of the carrier wave is altered in accordance with the amplitude of the modulating signal. The frequency of the carrier wave is not altered in amplitude modulation. It is the inverse of frequency modulation.

Q98. Three resistors each having value 'R' are connected as shown in figure. What is the equivalent resistance between 'X' and 'Y'?

• A. 3R✓
• B. R
• C. R/3
• D. R3

Explanation: The resistors are connected in a series so the final resistance between x and y would be the sum of all resistances, R+R+R=3R

Q99. How many types of modulations are possible with sinusoidal carrier?

• A. Only one
• B. Two
• C. Three✓
• D. Four

Explanation: The carrier signal is a sine wave at the carrier frequency. The sine wave has three characteristics that can be altered. The term that may be varied is the carrier voltage Ec, the carrier frequency FC, and the carrier phase angle θ. So three forms of modulations are possible.

Q100. A neutron having mass equal to a proton (mp = 1.6 x 10-27 kg) is moving in a magnetic field of intensity 1.20 x 10-3 T with a speed of 2.0 x 107 ms-1 . What is the maximum force experienced by the neutron?

• A. 3.84 x 10-15 N
• B. 0✓
• C. 3.84 x 10-12 N
• D. 38.4 x 10-15 N

Explanation: Neutrons do not experience magnetic fields because it's a neutral particle, moving charged particles only experience the magnetic force

Q101. Newton's third law can be derived from:

• A. Newton's first law
• B. Newton's second law✓
• C. Both Options A and B are correct
• D. They are unrelated

Explanation: Newton's second law provides a mathematical description of force as it relates to mass and acceleration, forming the basis for understanding interactions between objects. From these interactions, Newton's third law can be derived, stating that for every action, there is an equal and opposite reaction. Newton's first law does not offer this mathematical basis, as it focuses solely on the state of motion without external forces. The option suggesting they are unrelated is incorrect, as Newton's laws collectively describe motion and force interactions. Thus, the correct answer is option B.

Q102. Which of the following statements is incorrect?

• A. ∆Hn can be determined by a glass calorimeter
• B. ∆Hc can be determined by a bomb calorimeter
• C. ∆Hlatt of NaCl is 787 kJ mol-1
• D. Na(s) → Na(g) + ∆H = -108 kJ mol-1✓

Explanation: The correct answer is Option C. The lattice enthalpy of NaCl should be a positive value, indicating the energy required to break the ionic bonds, not a negative value as suggested. Option A is correct as it describes the use of a glass calorimeter in measuring enthalpy changes, typically for reactions at constant pressure. Option B accurately describes the function of a bomb calorimeter in determining the heat of combustion. Option D incorrectly states the ∆H value for the atomization of sodium, which should be positive, reflecting the endothermic nature of the process.

Q103. Tropical plants such as sugarcane show high efficiency of CO2 fixation because of:

• A. Calvin cycle
• B. Hatch-slack✓
• C. TCA-cycle
• D. All of these

Explanation: The high efficiency of carbon dioxide (CO2) fixation in C4 plants, including tropical plants like sugarcane, is indeed associated with the Hatch-Slack pathway. The Hatch-Slack pathway, also known as C4 photosynthesis, is a mechanism that allows these plants to efficiently fix carbon dioxide even under high temperatures and intense sunlight.