Sindh Mcat Nts 2015 Lumhs — Solved Past Paper with Answers

Q1. Select the incorrect segment from the following:For his birthday which is on 1st February, I shall give him a bicycle.

• A. For
• B. birthday
• C. 1st February
• D. bicycle
• E. No Error✓

Explanation: The sentence 'For his birthday which is on 1st February, I shall give him a bicycle.' is grammatically correct. Each part of the sentence is properly constructed and appropriate for the meaning intended. Thus, 'No Error' is the correct choice. The other options are incorrect because they point to segments that are used correctly in the sentence.

Q2. Select the incorrect segment from the following:We intend to have this wall taken down in order to convert the two room into one.

• A. We intend
• B. have
• C. down
• D. two room✓
• E. No Error

Explanation: The segment 'two room' is incorrect because the noun 'room' should be plural to match the number 'two'. Therefore, it should be 'two rooms'. The other segments of the sentence are grammatically correct: 'We intend' properly introduces a plan, 'have' is the correct verb form, and 'down' correctly describes the action related to the wall.

Q3. Choose the word most similar in meaning to the capitalized one:FURIOUS

• A. Cool
• B. Peaceful
• C. Angry✓
• D. Sensible

Explanation: The word 'furious' denotes a very high level of anger, making 'angry' the most similar in meaning. 'Cool' and 'peaceful' suggest calmness and lack of anger, which are opposites of 'furious'. 'Sensible' pertains to rational thinking, not an emotional state like 'furious'.

Q4. Choose the word most similar in meaning to the capitalized one:DOUBTFUL

• A. Unsure✓
• B. Certain
• C. Accurate
• D. Selected

Explanation: The word Unsure aligns with Doubtful as both words convey a lack of certainty. When someone is doubtful, they are uncertain or hesitant about something. On the other hand, Certain is the direct opposite of doubtful, suggesting complete confidence. Accurate relates to precision and correctness, not uncertainty. Selected refers to something that has been chosen, which does not convey any form of doubt or certainty.

Q5. Choose the word most nearly opposite in meaning to the capitalized one:SUCCEED

• A. Do well
• B. Flourish
• C. Fail✓
• D. Bloom

Explanation: The correct answer is 'Fail' because it is the antonym of 'Succeed'. To succeed means to achieve a goal, while to fail means the opposite—falling short of achieving the desired outcome. The other options—'Do well', 'Flourish', and 'Bloom'—all imply success or growth, aligning more closely with succeeding rather than opposing it.

Q6. Choose the word most nearly opposite in meaning to the capitalized one:VIOLENT

• A. Aggressive
• B. Sadistic
• C. Nasty
• D. Obsessive
• E. Peaceful✓

Explanation: The word 'violent' describes behavior that is forceful and likely to cause harm. The opposite of this is 'peaceful,' which refers to a state of calmness and non-aggression. The other options—aggressive, sadistic, nasty, and obsessive—do not convey an opposite meaning to violent. Instead, they either share similar aggressive connotations or are unrelated to the concept of violence.

Q7. There is a striking and unhappy contrast between man’s brilliant success at solving scientific problems and his miserable failure to solve so many of his political and social problems.It is natural, indeed wise, to ask whether science cannot be applied more effectively to the cure of the social and political ills of the gathering world.There is, of course, much that science can do and is doing. Science adds enormously to the comfort and interest of modern living. It is doing much to diminish the social evils of poverty and disease.Without doubt, many social, political, and economic problems would be more wisely handled if they were treated with unprejudiced objectivity and strict regard for truth which characterizes the work of the physical scientist.It's possible to handle political and economic problems scientifically?

• A. The aptness and truth-loving nature of scientific methods can greatly assist in resolving political and economic issues.✓
• B. Political and economic problems do not exist in scientifically advanced societies.
• C. Political and economic problems are inherently unsolvable.
• D. Solving social and economic problems is crucial for development.

Explanation: The correct answer is Option A. The passage suggests that the objective and truth-seeking nature of scientific methods can be beneficial in addressing political and economic issues. This is supported by the idea that applying a scientific approach could lead to more effective resolution of such problems. Option B is incorrect because scientific development does not automatically eliminate political and economic issues. Option C is incorrect as it dismisses the possibility of solving these problems, which contradicts the passage. Option D, while true, does not relate specifically to the role of scientific methods in solving these problems.

Q8. There is a striking and unhappy contrast between man’s brilliant success at solving scientific problems and his miserable failure to solve so many of his political and social problems.It is natural, indeed wise, to ask whether science cannot be applied more effectively to the cure of the social and political ills of the gathering world.There is, of course, much that science can do and is doing. Science adds enormously to the comfort and interest of modern living. It is doing much to diminish the social evils of poverty and disease.Without a doubt, many social, political, and economic problems would be more wisely handled if they were treated with unprejudiced objectivity and strict regard for truth which characterises the work of the physical scientist.Which of the following contrasts is drawn in the given passage?

• A. Difference between social and economic problems.
• B. Difference between comforts and modern living.
• C. Difference in scientific successes, social and economic failures.✓
• D. Difference between poverty and disease.

Explanation: The correct answer is Option C: 'Difference in scientific successes, social and economic failures.' The passage explicitly contrasts the success in solving scientific problems with the ongoing failures in tackling political and social issues. This is evident from the first line of the passage. Option A is incorrect as it does not address the contrast outlined in the passage. Option B is incorrect as it misinterprets the passage's mention of comforts as a benefit of science, not a contrast. Option D is incorrect because poverty and disease are mentioned as issues science is addressing, not as contrasting elements.

Q9. Complete the sentences by choosing the most appropriate option from the following:Young people are often _ than old people.

• A. more enthusiastic✓
• B. most enthusiastic
• C. have enthusiastic
• D. had enthusiastic

Explanation: The correct answer is 'more enthusiastic'. The sentence compares young people to old people using 'than', which signals the need for a comparative form. 'More' is the correct comparative form to use with the adjective 'enthusiastic'. The option 'most enthusiastic' is incorrect because 'most' is a superlative used for comparing more than two items. 'Have enthusiastic' and 'had enthusiastic' are grammatically incorrect constructions as they do not appropriately utilize the adjective 'enthusiastic'.

Q10. I forgot _ take down his telephone number.

• A. too
• B. to✓
• C. the
• D. this
• E. though

Explanation: The correct answer is 'to' because it is used to form the infinitive 'to take', which is needed after 'forgot'. The word 'too' suggests excess, 'the' is an article, 'this' is a demonstrative pronoun, and 'though' is a conjunction, none of which appropriately fit into the sentence structure.

Q11. Which nucleic acid bases are pyrimidine?

• A. Adenine, Cytosine, and Thymine
• B. Cytosine, Thymine, and Uracil✓
• C. Cytosine, Thymine, and Adenine
• D. Guanine, and Adenine
• E. Uracil, Cytosine, and Adenine

Explanation: Nucleic acids contain five different nucleotide bases: adenine, guanine, cytosine, thymine, and uracil. Among these, adenine and guanine are classified as purines, which are double-ring structures. The pyrimidines, which have a single-ring structure, are cytosine, thymine, and uracil. Therefore, the correct answer is Cytosine, Thymine, and Uracil. The other options include adenine or guanine, which are not pyrimidines.

Q12. Which explains why Phenylketonuria has not been eradicated?

• A. Phenylketonuria is an inherited disease, so vaccination is not possible.✓
• B. Identification of carriers is too difficult as they show no symptoms.
• C. Phenylketonuria gives the individual some resistance against malaria.
• D. The gene responsible for Phenylketonuria has a high rate of mutation.

Explanation: Phenylketonuria (PKU) is an inherited metabolic disorder caused by a deficiency in the enzyme phenylalanine hydroxylase. This genetic basis means that PKU cannot be eradicated through conventional public health measures like vaccination. Effective management involves dietary restrictions, but carriers continue to pass the gene to offspring. Option A is correct because it accurately captures the hereditary nature of PKU, which is why it cannot simply be eradicated. Option B is incorrect because although carriers are asymptomatic, they can be identified through genetic testing. Option C is incorrect because PKU does not confer any known advantages, such as resistance to malaria. Option D is incorrect as the mutation rate of the PKU gene is not abnormally high.

Q13. Organisms of which of the following kingdoms have absorptive modes of nutrition?

• A. Prokaryotes
• B. Fungi✓
• C. Protoctista
• D. Plantae

Explanation: The correct answer is Fungi. Fungi are known for their absorptive mode of nutrition, where they secrete enzymes into the environment to digest organic material externally, then absorb the resulting nutrients. This mode of nutrition is distinct from other kingdoms.Prokaryotes have varied nutritional strategies, but absorption is not a defining characteristic. Protoctista also exhibit diverse nutritional methods, including photosynthesis and ingestion. Plantae are primarily autotrophic and use photosynthesis to obtain energy, not absorption.

Q14. The following are all parts of the heart that control the heart action. The following are all parts of the heart that control the heart action.1. Purkinje tissue2. Sinoatrial node (SAN)3. Atrioventricular node (AVN)Which option corresponds correctly to Atrial and Ventricular contraction?

• A. Option A: The signal starts in the Purkinje tissue, triggering atrial contraction, followed by the SAN causing ventricular contraction.
• B. Option B: The Sinoatrial node (SAN) initiates the atrial contraction, followed by the Atrioventricular node (AVN) and Purkinje fibers that facilitate ventricular contraction.✓
• C. Option C: The AVN initiates both atrial and ventricular contractions simultaneously.
• D. Option D: The Purkinje fibers initiate the contraction sequence, followed by the SAN and AVN.

Explanation: The correct answer is Option B. The Sinoatrial node (SAN) is known as the heart's natural pacemaker because it initiates the electrical impulse that causes atrial contraction. The impulse then travels to the Atrioventricular node (AVN), which briefly delays the impulse to allow the atria to fully contract before passing it down the bundle of HIS and into the Purkinje fibers. This pathway facilitates the sequential contraction of the ventricles. Options A, C, and D are incorrect because they either misplace the role of the Purkinje fibers or incorrectly assign the initiation of the contraction sequence to nodes that do not perform that function.

Q15. What is a characteristic of all catalysts?

• A. They are broken down in a reaction
• B. They are made of protein
• C. They are not changed by the reaction✓
• D. They can not change the rate of the reaction

Explanation: Catalysts are substances that speed up chemical reactions without being consumed or altered permanently in the process. This characteristic allows them to be used repeatedly. Option C is correct because it accurately describes this fundamental property of catalysts. Option A is incorrect because catalysts are not broken down in reactions. Option B is incorrect because not all catalysts are proteins; many are metals or other non-protein substances. Option D is incorrect because the defining feature of a catalyst is its ability to change the rate of a reaction, usually by lowering the activation energy.

Q16. The diagram shows the teeth of the lower jaw of a human. Which tooth is an incisor?

• A. A
• B. B✓
• C. C
• D. D

Explanation: Incisors: These are the sharp, flat teeth at the front of your mouth used for biting and cutting food into smaller pieces. Canines: Located next to the incisors, these pointed teeth are used for tearing and gripping food. Premolars: Situated behind the canines, premolars have a flat surface and are used for crushing and shredding food. Molars: These are the large, flat teeth at the back of your mouth that are designed for grinding and crushing food to prepare it for swallowing.

Q17. A person with emphysema must consciously contract muscles in order to breathe out. What makes his muscle contraction necessary?

• A. Constriction of bronchioles
• B. Excess mucus blocking the air passages
• C. Paralysis of cilia in the air passages
• D. Loss of elasticity in the alveolar walls✓
• E. None of the given options

Explanation: In emphysema, the primary issue is the loss of elasticity in the alveolar walls, which impairs lung recoil during exhalation. This necessitates the use of respiratory muscles to actively expel air from the lungs. While bronchoconstriction, excess mucus, and cilia dysfunction can contribute to breathing difficulties, they are not the primary reasons for the need for muscle contraction in exhalation in emphysema. Therefore, the correct answer is the loss of elasticity in the alveolar walls.

Q18. Which row describes the shoulder joint of an arm?

• A. Humerus and scapula connection✓
• B. Hip joint structure
• C. Elbow joint function
• D. Wrist joint motion

Explanation: The correct answer is the option describing the connection between the humerus and scapula, which forms the shoulder joint, a ball-and-socket joint allowing for a wide range of motion. The other options incorrectly describe different joints: the hip, elbow, and wrist, each with distinct structures and functions unrelated to the shoulder.

Q19. Which of the following types of mammalian cell does not carry out oxidative phosporylation?

• A. Erythrocytes✓
• B. Neuron
• C. Oxyntic cell
• D. Cardiac muscle cell

Explanation: Erythrocytes, or red blood cells, do not perform oxidative phosphorylation because they lack mitochondria, the organelles where this process occurs. Instead, they rely on glycolysis, a process that occurs in the cytoplasm and produces ATP anaerobically. This is in contrast to neurons, oxyntic cells, and cardiac muscle cells, all of which contain mitochondria and depend on oxidative phosphorylation for efficient ATP production. Neurons and cardiac muscle cells, in particular, have high energy demands, necessitating the presence of mitochondria for sustained ATP synthesis.

Q20. Occasionally, non-disjunction of the entire genome occurs during meiosis producing abnormal gametes. Which type of genetic variation may result when one such gamete is fertilised by a normal gamete?

• A. Aneuploidy
• B. Deletion
• C. Inversion
• D. Translocation
• E. Triploidy✓

Explanation: Triploidy results from the fertilization of a gamete that contains an entire extra set of chromosomes by a normal gamete, leading to an organism with three sets of chromosomes. This can occur when non-disjunction affects the entire genome during meiosis. In contrast, aneuploidy involves a single extra or missing chromosome rather than a complete extra set. Deletion, inversion, and translocation involve structural changes to chromosomes rather than changes to the number of chromosome sets.

Q21. The diagram shows two pairs of homologous chromosomes. Which stage of nuclear division is shown?

• A. Anaphase of mitosis
• B. Anaphase 1 of meiosis
• C. Metaphase of mitosis
• D. Metaphase 1 of meiosis✓

Explanation: Metaphase 1 of meiosis is characterized by the alignment of homologous chromosome pairs (bivalents) at the cell's equator, where they are attached to spindle fibers. This stage is crucial for genetic diversity due to independent assortment, where the arrangement of homologous pairs is random. Other stages, such as anaphase of mitosis and metaphase of mitosis, involve different arrangements and separations of chromosomes.

Q22. Right atrium is seperated from right ventricle by:

• A. Bicuspid valve
• B. Tricuspid Valve✓
• C. Semilunar valve
• D. Interatrial Septum

Explanation: The right atrium is separated from the right ventricle by the tricuspid valve. The tricuspid valve is a three-leaflet valve that allows blood to flow from the right atrium to the right ventricle. The tricuspid valve is located at the opening of the right ventricle. The tricuspid valve is made up of three leaflets, which are called the septal leaflet, the anterior leaflet, and the posterior leaflet. The leaflets are attached to the papillary muscles by chordae tendineae. The papillary muscles are attached to the walls of the right ventricle.

Q23. Nociceptors are specialized for the detection of sense of:

• A. Deep pressure
• B. Tough
• C. Pain✓
• D. Temperature

Explanation: Specialized peripheral sensory neurons known as nociceptors alert us to potentially damaging stimuli at the skin by detecting extremes in temperature and pressure and injury-related chemicals, and transducing these stimuli into long-ranging electrical signals that are relayed to higher brain centers.

Q24. The pancreas is stimulated to secrete its digestive enezyme by;

• A. the liver
• B. bile
• C. the gallbladder
• D. secretin✓
• E. insulin

Explanation: The correct answer is secretin. Secretin is released by the small intestine in response to acidic chyme entering from the stomach. It stimulates the pancreas to secrete bicarbonate-rich pancreatic juice, which helps neutralize the acid and provides an optimal environment for digestive enzymes. Cholecystokinin, mentioned in the original explanation, also plays a role in stimulating pancreatic enzyme secretion, but the question specifically asks for the stimulus that directly triggers the secretion of pancreatic digestive enzymes. The other options, such as the liver, bile, gallbladder, and insulin, do not directly stimulate the pancreas to secrete digestive enzymes.

Q25. Which of the follwoing is different from the others:

• A. Lycopsida
• B. Mimosaceae✓
• C. Pteropsida
• D. Caesalpiniaceae
• E. Anthocerotae

Explanation: The difference is that while options a, c, e, and d refer to different groups of plants (lycopsids, pteropsids, hornworts, and the Caesalpiniaceae family), option b (Mimosaceae) refers to a family of flowering plants within the same order as option d (Caesalpiniaceae). Therefore, option b) Mimosaceae is different from the others as it represents a different level of classification (family) compared to the others.

Q26. Pheretima posthuma is the scientific name of:

• A. planaria
• B. liver fluke
• C. tape worm
• D. ascaris
• E. earth worm✓

Explanation: The correct answer is earthworm. Pheretima posthuma is the scientific name for the common earthworm, a terrestrial invertebrate that plays a crucial role in soil health. The other options are incorrect because: Planaria are flatworms typically in the genus Dugesia; liver flukes belong to the class Trematoda and include species like Fasciola; tapeworms are from the class Cestoda; Ascaris is a genus of parasitic nematode worms. None of these organisms share the scientific name Pheretima posthuma.

Q27. The nuclei of both plant and animal cells contain one or more dense bodies known as nucleoli. Which one of the following correct describes the function of nucleoli?

• A. The formation of new DNA molecules
• B. The organization of the spindle during nuclear division
• C. The replication of mitochondria following nuclear division
• D. The formation of ribosomes✓

Explanation: The nucleolus is a vital sub-structure within the cell nucleus, primarily tasked with the synthesis of ribosomal RNA (rRNA) and the assembly of ribosomal subunits. These subunits are exported to the cytoplasm, where they form functional ribosomes, essential for protein synthesis. Option D is correct as it accurately describes this key function of the nucleolus.Option A is incorrect because DNA replication, while occurring in the nucleus, is not a function of the nucleolus. Option B is incorrect since spindle organization is handled by centrosomes, not the nucleolus. Option C is incorrect because mitochondrial replication is independent and does not involve the nucleolus.

Q28. The diagram shows a section through the human brain:What are the names of the parts labelled 1, 2 and 3?

• A. Option A: Cerebrum, Cerebellum, Medulla✓
• B. Option B: Frontal Lobe, Parietal Lobe, Occipital Lobe
• C. Option C: Thalamus, Hypothalamus, Pituitary Gland
• D. Option D: Pons, Midbrain, Medulla Oblongata

Explanation: The correct answer is Option B: Frontal Lobe, Parietal Lobe, Occipital Lobe. These parts are distinct regions of the cerebral cortex, each with specific functions: the frontal lobe is involved in executive functions and decision making, the parietal lobe processes sensory input, and the occipital lobe is primarily responsible for visual processing. Options A, C, and D refer to different brain structures or regions that do not match the labelled parts in the diagram.

Q29. A tadpole’s tail is gradually broken down during metamorphosis into an adult frog. Which organelle increases in number in the cells of the tail at this time?

• A. Centriole
• B. Endoplasmic reticulum
• C. Golgi Apparatus
• D. Lysosomes✓

Explanation: The correct answer is lysosomes. During metamorphosis, the tadpole's tail is broken down and absorbed into the body as the tadpole transforms into a frog. This process requires the digestion of tail tissue, which is facilitated by lysosomes. Lysosomes are organelles that contain digestive enzymes capable of breaking down proteins, lipids, carbohydrates, and nucleic acids. The increased number of lysosomes in the cells of the tadpole's tail reflects their essential role in tissue breakdown and recycling during metamorphosis.Other organelles such as centrioles, endoplasmic reticulum, and Golgi apparatus are involved in different cellular functions, primarily related to cell division and protein synthesis, and therefore are not directly involved in the breakdown of cellular components.

Q30. Which of the following statements is true about the desert ecosystem?

• A. The desert experiences a short dry season and temperatures remain below 18˚C throughout the year
• B. The desert's subsoil is permanently frozen
• C. Desert rainfall can reach up to 300 cm per year
• D. In a desert, evaporation exceeds rainfall✓

Explanation: The correct answer is that evaporation exceeds rainfall in desert ecosystems. Deserts are defined by their arid conditions, where the amount of water lost through evaporation and transpiration is greater than the amount of precipitation received. This leads to very dry environments with limited water availability. Option A is incorrect as deserts typically experience high daytime temperatures and long dry seasons. Option B is incorrect because permanently frozen subsoil is typical of tundra, not deserts. Option C is incorrect because deserts receive significantly less rainfall, usually less than 25 cm per year.

Q31. Lamarcks theory is based on all of the follwoing points EXCEPT:

• A. Effects of Environment
• B. Use and Disuse of organs
• C. Natural Selection✓
• D. Inheritance of acquired characters

Explanation: Lamarck's theory is not based on natural selection, as this concept was proposed by Charles Darwin. Lamarck's focus was on the heritability of acquired characteristics, where organisms could pass on traits acquired during their lifetime to their offspring. This mechanism of inheritance of acquired characteristics formed the core of Lamarck's evolutionary theory.

Q32. The blastoderm in chicks splits into

• A. Epimere and Hypomere
• B. Epiblast and Epimere
• C. Epimere and Mesomere
• D. Epiblast and Hypoblast✓

Explanation: In chicks, the blastoderm splits into two distinct layers during early embryonic development. The upper layer, called the epiblast, gives rise to the embryo proper, forming all the tissues and organs of the chick. The lower layer, called the hypoblast, contributes to the extraembryonic structures, such as the yolk sac, but does not form the main body of the embryo. This division into epiblast and hypoblast is a crucial step that sets the stage for subsequent processes like gastrulation and the formation of the three germ layers.

Q33. For the impulse to transfer from presynaptic to post-synaptic neuron, the substance required is:

• A. Sodium
• B. Potassium
• C. Protein
• D. Calcium✓

Explanation: Calcium ions (Ca2+) are required for the transfer of impulses from the presynaptic neuron to the postsynaptic neuron. When an action potential reaches the presynaptic terminal, it triggers the opening of voltage-gated calcium channels. The influx of calcium ions into the presynaptic terminal leads to the release of neurotransmitter molecules from vesicles into the synaptic cleft. These neurotransmitters then bind to receptors on the postsynaptic membrane, transmitting the impulse from one neuron to another.

Q34. The floral formula of family rosacea or rose family is:

• A. Ca 5 Co 5 A1
• B. Ca 4 Co 4 A8
• C. Ca 5 Co 5 A∞✓
• D. Ca 6 Co 6 A12
• E. Ca 3 Co 3 A9

Explanation: The correct floral formula for the Rosaceae family is Ca 5 Co 5 A∞, indicating 5 sepals, 5 petals, and many stamens, a hallmark of this family. This family is most common in temperate and subtropical regions of the Northern Hemisphere. The other options suggest floral formulas that do not match the typical characteristics of Rosaceae, either due to the number of floral parts or stamen count.

Q35. The gland that responds to external conditions of light and darkness as sensed through the eyes is:

• A. Thymus gland
• B. Adrenal gland
• C. Pineal gland✓
• D. Thyroid gland
• E. Parathyroid gland

Explanation: The main function of the pineal gland is to receive information about the state of the light-dark cycle from the environment and convey this information by the production and secretion of the hormone melatonin.

Q36. In which of the following cell organelles can you find high concentrations of RNA?1. Endoplasmic reticulum2. Golgi Apparatus3. Ribosomes 4. Mitochondria

• A. 1 only
• B. 2 only
• C. 1 and 3✓
• D. 2 and 3

Explanation: Endoplasmic Reticulum (ER): High RNA concentration is found in the rough ER due to ribosomes on its surface, actively involved in protein synthesis.Golgi Apparatus: The Golgi Apparatus is not a primary site of high RNA concentration.Ribosomes: Ribosomes contain a significant amount of RNA (rRNA) and are directly involved in protein synthesis.Mitochondria: While mitochondria contain mitochondrial DNA (mtDNA, a type of RNA), they are not primarily known for high RNA concentrations related to protein synthesis.

Q37. Which row correctly shows structures which contain a nucleus?

• A. Row A
• B. Row B
• C. Row C
• D. Row D✓

Explanation: The correct answer is Row D. Mammal red blood cells do not contain a nucleus. In growing root hairs, the nucleus is positioned away from the apex. Tracheids in the xylem are without a nucleus and cytoplasm. Rows A, B, and C do not accurately represent structures containing a nucleus.

Q38. Tay-Sachs disease occurs when cells are unable to produce an enzyme, leading to a build up of certain lipids in cells. Which cell structure would not function correctly, resulting in the disease?

• A. Golgi apparatus
• B. Lysosome✓
• C. Mitochondria
• D. Smooth endoplasmic reticulum

Explanation: The correct answer is lysosome. Tay-Sachs disease is caused by a deficiency of the enzyme β-hexosaminidase A, which is located in the lysosomes. This deficiency leads to the accumulation of GM2 gangliosides, a type of lipid, which the lysosome cannot break down, causing the symptoms associated with Tay-Sachs disease. The other options are incorrect as they perform different functions: the Golgi apparatus is for protein and lipid sorting, mitochondria produce energy, and the smooth endoplasmic reticulum is involved in lipid synthesis and detoxification.

Q39. How does sucrose move from chloroplasts to the phloem?I. apoplast pathwayII. symplast pathwayIII. mass flow

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

Explanation: The pathway that sucrose molecules use to travel to the sieve tubes is not fully understood yet. The molecules may move by the: symplasticpathway (through the cytoplasm and plasmodesmata) which is a passive process as the sucrose molecules move by diffusion or apoplastic pathway (through the cell walls) which is an active process

Q40. By which process does oxygen pass out of the stem and root of a plant?

• A. Diffusion✓
• B. Osmosis
• C. Translocation
• D. Transpiration

Explanation: The exchange of gases in the roots and stems of a plant occurs by diffusion. In diffusion, gases move from an area of higher concentration to an area of lower concentration. Oxygen, which is needed for cellular respiration, diffuses into the plant cells, and carbon dioxide, a byproduct of respiration, diffuses out into the soil or atmosphere. Osmosis, on the other hand, is specifically the movement of water molecules and does not involve the exchange of gases. Translocation involves the transport of organic compounds, not gases, within the plant. Transpiration is related to water movement and loss from the plant, rather than gas exchange directly.

Q41. Which of following is capable of oxidizing an aqueous solution Sn+2 ions to Sn+4 ions?

• A. Aqueous Fe+2
• B. Aqueous Li+1
• C. Aquoeus Mg+2
• D. Aqueos Fe+3✓

Explanation: Fe3+ is capable of oxidising Sn2+ to Sn4+ because standard reduction potential of Fe3+ is higher than that of the Sn2+ and hence Fe3+ have a greater tendency to accept electrons.

Q42. Which of the following reaction actually occurs?

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

Explanation: In order for a reaction to occur, the Ecell of the two electrodes must be a positive value.Ecell=Ered−EoxIn the question, Eox values are given. To convert from Eox to Ered or vice versa, only the +/- signs have to be reversed.E cell for all given options must be calculated in order to find out the one with a positive value.A: -0.76-(-0.8)= 0.04B: 0.8-0.76=0.04C: -0.76-(-0.8)= 0.04D: 0.76-(-0.8)=1.56Since in reaction D, the highest positive value for E cell is obtained, this is the more feasible reaction and will occur in priority to the rest.

Q43. The combustion analysis of an organic compound shows it to contain 65.44% carbon, 5.5% hydrogen and 29.06% oxygen. If the molecular mass of this compound is 110.5 g.mol-1. Calculate the molecular formula of the compound.

• A. C6H6O2✓
• B. C6H3O2
• C. C6H6O4
• D. C4H6O2
• E. C6H4O2

Explanation: To find the molecular formula, first determine the empirical formula. Divide the percentage of each element by its atomic mass: C (65.44/12), H (5.50/1), O (29.06/16). This gives you the moles of each element: C = 5.45, H = 5.50, O = 1.82. Divide each by the smallest number of moles, 1.82, to get the simplest whole number ratio: C : H : O = 3 : 3 : 1, giving the empirical formula C3H3O. The empirical formula mass is 55 g/mol. With the given molecular mass of 110.5 g/mol, divide this by the empirical formula mass: 110.5/55 = 2. Thus, the molecular formula is C6H6O2. The other options are incorrect as they do not match the calculated molecular mass or the derived empirical formula ratio.

Q44. Mg metal reacts with HCl to give hydrogen gas. What is the minimum volume of HCl solution (27% by weight) required to produce 12.1 g of H2? The density of HCl solution is 1.14 g/cm3. Mg(s) + 2HCl(aq) → MgCl2 (aq) + H2 (g)

• A. 1432 cm3✓
• B. 1852 cm3
• C. 4125 cm3
• D. 52.5 cm3

Explanation: First, calculate the moles of H2 produced using its molar mass: Moles of H2 = 12.1 g / 2 g/mol = 6.05 moles. According to the balanced equation, 2 moles of HCl are needed to produce 1 mole of H2. Therefore, 12.1 moles of HCl are required for 6.05 moles of H2. Calculate the mass of HCl needed: Mass of HCl = 12.1 moles × 36.458 g/mol = 437.64 g. Considering the HCl solution is 27% by weight, calculate the total mass of the solution: Total mass = 437.64 g / 0.27 = 1620.15 g. Finally, use the density to find the volume: Volume = Mass / Density = 1620.15 g / 1.14 g/cm3 = 1421.19 cm3, approximated to 1432 cm3. Other options result from errors in stoichiometry, concentration adjustment, or density application.

Q45. 250 cm3 of hydrogen is cooled from 127˚C to -27˚C by keeping the pressure constant. Calculate the new volume of the gas at low temperature.

• A. 100 cm3
• B. 200 cm3
• C. 250 cm3
• D. 153 cm3✓
• E. 130 cm3

Explanation: The correct answer is 153 cm3. To find the new volume of the gas, use Charles's Law, which states that the volume of a gas is directly proportional to its temperature in Kelvin at constant pressure. First, convert the temperatures from Celsius to Kelvin: T1 = 127 + 273 = 400 K and T2 = -27 + 273 = 246 K. Then set up the equation using the initial and final conditions: V1/T1 = V2/T2, which simplifies to 250/400 = V2/246. Solving for V2 gives V2 = 250 * (246/400) = 153 cm3. The other options are incorrect because they either overestimate or underestimate the effect of the temperature change on the volume.

Q46. A sample of nitrogen gas is enclosed in a vessel of volume 380 cm3 at 120˚C and pressure of 101325Nm2 . This gas is transferred to a 10 dm3 and cooled to 27˚C. Calculate the pressure in Nm-2 exerted by the gas at 27˚C.

• A. 3252.2 Nm-2
• B. 1000 Nm-2
• C. 2938.4 Nm-2✓
• D. 2580 Nm-2

Explanation: To find the final pressure, use the combined gas law: P1V1/T1 = P2V2/T2. Initial conditions: V1 = 0.38 dm3, T1 = 393 K, P1 = 101325 Nm-2. Final conditions: V2 = 10 dm3, T2 = 300 K. Solving for P2 gives 2938.4 Nm-2. Other options result from incorrect calculations or conversions. For instance, option A assumes incorrect temperature or volume conversions, while option B neglects the substantial initial pressure. Option D miscalculates the pressure by incorrectly applying the gas law.

Q47. 250 cm3 of the sample of hydrogen effuses four times as rapidly as 250 cm3 of an unknown gas. Calculate the molar mass of unknown gas.

• A. 45 g mol-1
• B. 40 g mol-1
• C. 41.2 g mol-1
• D. 38.2 g mol-1
• E. 32 g mol-1✓

Explanation: Graham's law states that the rate of diffusion or effusion of a gas is inversely proportional to the square root of its molar mass. The Formula can be written as: Let the rate of diffusion (r₁) of unknown gas be x and the molar mass of unknown gas be M₁. So, 250 cm³ of the sample of hydrogen refuses four times as rapidly as 250 cm³ of an unknown gas. Thus, the rate of diffusion (r₂) of a sample of hydrogen is 4x. We know that the rate of diffusion and molar mass of gases can be expressed as: r₁ / r₂ = √(M₂ / M₁) x / 4x = √(2 / M₁) 1 / 4 = √(2 / M₁) On squaring both sides we get. 1 / 16 = 2 / M₁ M₁ = 2 * 16 M₁ = 32 g/mol Therefore, the molar mass of unknown gas is 32 g/mol.

Q48. The following reaction was allowed to reach the state of equilibrium:2A(aq) + B(aq) ⇌ C(aq)The initial amounts of the reactants present in one dm3 of solution were 0.50 mole of A and 0.60 moles of B. At equilibrium, the amounts were 0.20 moles of A and 0.45 mole of B and 0.15 mole of C. Calculate the equilibrium constant Kc.

• A. 7.5
• B. 10
• C. 8.3✓
• D. 11.7
• E. 12.5

Explanation: To calculate the equilibrium constant Kc for the reaction 2A(aq) + B(aq) ⇌ C(aq), use the concentrations at equilibrium:[A] = 0.20 mol/dm3[B] = 0.45 mol/dm3[C] = 0.15 mol/dm3The equilibrium expression is given by:Kc = [C]/([A]^2[B])Substitute the equilibrium values:Kc = 0.15/(0.20^2 * 0.45) = 8.3Options A, B, D, and E result from incorrect calculations or assumptions, such as using initial concentrations or incorrect stoichiometric coefficients in the expression.

Q49. N2 and H2 combine to give NH3. The value Kc in the reaction at 500˚C is 6.0 x 10-2. Calculate the value of Kp for this reaction.

• A. 1.5 x 10-7
• B. 1.5 x 10-5✓
• C. 1.5 x 10-6
• D. 3.5 x 10-7
• E. 4.5 x 105

Explanation: The reaction is: N2 + 3H2 ⇌ 2NH3. To find Kp from Kc, use the formula: Kp = Kc (RT)Δn, where Δn is the change in moles of gas (products - reactants). Here, Δn = 2 - (1 + 3) = -2. Convert the temperature to Kelvin: 500°C = 773 K. The gas constant R = 0.0821 L atm / K mol. So, Kp = 6.0 x 102 * (0.0821 * 773)-2. This calculates to Kp = 1.5 x 10-5.The other options result from common calculation errors, such as using the wrong value for Δn, temperature in Kelvin, or gas constant.

Q50. How will the equilibrium of the following reaction be affected if more chlorine is added?PCI5 ⇌ PCI3 + Cl2 (g)

• A. It will be shifted to the right
• B. It will be shifted to the left✓
• C. It will be unaffected
• D. The effect on the equilibrium cannot be determined without more information
• E. More PCl3 will be produced.

Explanation: Le Chatelier's Principle explains that a system at equilibrium will adjust to counteract any changes in concentration, pressure, or temperature. When more chlorine (Cl2) is added to the reaction PCl5 ⇌ PCl3 + Cl2, the system will respond by shifting the equilibrium to the left, toward the formation of PCl5, in order to reduce the concentration of the added chlorine.Option A is incorrect because the equilibrium will not shift to the right to produce more Cl2 when its concentration is increased. Option C is incorrect because equilibrium is indeed affected by changes in concentration. Option D is incorrect because the shift can be predicted using Le Chatelier's Principle. Option E is incorrect because, overall, the shift will decrease the amount of PCl3 as the system seeks to consume the excess Cl2.

Q51. The biggest ion from the following:

• A. Al3+
• B. Ba2+✓
• C. Na+
• D. Mg2+

Explanation: As you go down the rows of the periodic table, the cationic radius increases. Within a row (a "period"), the cationic radius decreases as you go across because you have the same number of electrons but a greater number of protons in the nucleus as you go across the table. So the correct order is Ba2+ > Na+ > Mg2+ > Al3+ (from largest to smallest cation by radius).

Q52. Titanium has the electronic structure, 1s2, 2s2, 2p6, 3s2, 3p6, 3d2, 4s2.Which of the following compounds is unlikely to exist?

• A. K2TiO4✓
• B. K3TiF6
• C. TiCl3
• D. TiO
• E. TiO2

Explanation: Titanium typically exhibits oxidation states of +2, +3, and +4. In the compound K2TiO4, titanium would need to have an oxidation state of +6, which is uncommon and thus makes the existence of this compound unlikely. The other compounds, such as K3TiF6, TiCl3, TiO, and TiO2, correspond to oxidation states that titanium is known to exhibit, making them more likely to exist.

Q53. The structure is H2SO4:

• A. Pyramidal
• B. Tetrahedral✓
• C. Irregular pentagonal
• D. Distorted

Explanation: The correct answer is 'Tetrahedral'. The H2SO4 molecule features a sulfur atom centrally bonded to four oxygen atoms, following a tetrahedral electron pair geometry. This results from the sp3 hybridization of the sulfur atom, accommodating the double bonds with two oxygen atoms and single bonds with two hydroxyl groups. The other options are incorrect as they do not describe the geometric or electronic arrangement of the sulfuric acid molecule.

Q54. Why are large alkane molecules cracked to form smaller molecules?

• A. Alkanes with large molecules are not useful✓
• B. Small alkane molecules cannot be polymerized
• C. Crude oil does not contain small alkane molecules
• D. To meet the demand for small alkane molecules

Explanation: There is more demand for shorter alkane molecules and alkenes than for many of the longer chains formed during fractional distillation. This is where cracking comes in. Cracking allows large hydrocarbon molecules to be broken down into smaller, more useful hydrocarbon molecules.

Q55. The compounds shown have the same:

• A. Boiling point
• B. Melting point
• C. Percentage composition by mass✓
• D. Structural formula

Explanation: The correct answer is Option C: Percentage composition by mass. When compounds have the same molecular formula, they have the same percentage composition by mass, as the number and types of atoms are identical. This is a key concept in understanding isomerism. The other options are incorrect because boiling point, melting point, and structural formula can vary between isomers due to differences in molecular structure and intermolecular forces.

Q56. The structures of an acid and an alcohol are shown:

• A. Acid=Ethanoic, Alcohol=Butanol
• B. Acid=Ethanoic, Alcohol=Propanol
• C. Acid=Propanoic, Alcohol=Propanol
• D. Acid=Propanoic, Alcohol=Butanol✓

Explanation: The correct answer is Acid=Propanoic, Alcohol=Butanol. The acid contains three carbon atoms, which corresponds to propanoic acid, as 'propane' indicates three carbons and '-oic acid' is the suffix for carboxylic acids. The alcohol contains four carbon atoms, which corresponds to butanol, with 'butane' indicating four carbons and '-ol' being the suffix for alcohols.Options A and B incorrectly identify the acid as ethanoic, which would have only two carbon atoms. Option C correctly identifies the acid but incorrectly identifies the alcohol as propanol, which has only three carbon atoms.

Q57. The electronegativity of cesium is 0.7 and that of fluorine is 4.0. The bond is formed between the two is:

• A. Covalent
• B. Electrovalent✓
• C. Coordinate
• D. Metallic

Explanation: The correct answer is Electrovalent. The large electronegativity difference between cesium (0.7) and fluorine (4.0) suggests that cesium can easily donate an electron to fluorine, resulting in the formation of an ionic bond, also known as an electrovalent bond. In this bond, cesium becomes a positively charged ion (cation) and fluorine becomes a negatively charged ion (anion). The other options are incorrect because:Covalent: Typically involves the sharing of electrons with smaller electronegativity differences.Coordinate: Involves one atom providing both electrons for a bond, which is not the case here.Metallic: Involves a sea of delocalized electrons among metal atoms, not applicable to the non-metal fluorine.

Q58. Which of the following statements is not correct for an electron that has the quantum numbers n=4 and m=2?

• A. The electron may have the quantum number s=+½
• B. The electron may have the quantum number l=4✓
• C. The electron may have the quantum number l=3
• D. The electron may have the quantum number l=0,1,2,3

Explanation: The correct answer is Option B: The electron may have the quantum number l=4. This is incorrect because for a principal quantum number n=4, the azimuthal quantum number (l) can only be 0, 1, 2, or 3. The value of l is determined by the rule that l can range from 0 to n-1. Thus, l cannot be 4.Option A is correct because the spin quantum number s can be +½ or -½ for any electron.Option C is correct as l=3 is within the allowed range for n=4.Option D is correct because it lists all valid values of l for n=4.

Q59. Sodium carbonate reacts with SO2 in an aqueous solution to give:

• A. NaHCO3
• B. NaHSO3✓
• C. Na2SO3
• D. NaHSO4

Explanation: The correct product when sodium carbonate reacts with sulfur dioxide in an aqueous solution is sodium bisulfite (NaHSO3). This is shown in the balanced chemical equation: Na2CO3 + 2SO2 + H2O → 2NaHSO3 + CO2. Option A, NaHCO3, is not produced in this reaction. Option C, Na2SO3, requires a different reaction pathway. Option D, NaHSO4, involves sulfuric acid, which is not involved in this reaction.

Q60. In the extraction of aluminium, the function of cryolite is to:

• A. Lower the melting point of alumina✓
• B. Increase the melting point of alumina
• C. Remove impurities from alumina
• D. Minimise the anodic effect

Explanation: In the extraction of aluminium, cryolite acts as a solvent for alumina, primarily to lower its melting point. This is crucial because it allows the electrolytic reduction process to occur at temperatures around 900-950°C, which is significantly lower than the melting point of pure alumina (around 2050°C). This reduction in temperature makes the process more energy-efficient and economically viable. Cryolite also enhances the conductivity of the molten mixture, further facilitating the electrolysis process. Other options are incorrect because cryolite is not used to increase the melting point, remove impurities, or minimise the anodic effect.

Q61. Copper can be extracted from:

• A. Kupfernickel
• B. Sulphide ore✓
• C. Malachite
• D. Galena

Explanation: Copper is predominantly extracted from sulfide ores such as chalcopyrite through a process called pyrometallurgy, which involves high-temperature treatments like smelting. This method is energy-intensive and requires careful management of by-products like sulfur dioxide. Other ores, such as malachite, are less commonly used for large-scale extraction due to their lower copper content. Kupfernickel and galena are unsuitable for copper extraction as they are primarily sources of nickel and lead, respectively.

Q62. Formula for Potassium hexacyanoferrate (II) is:

• A. K4 [Fe (CN)6]✓
• B. K3 [Fe (CN)6]
• C. K4 [Fe2 (CN)6]
• D. K4 [Fe (NO2)6]
• E. K4[CO (NO2)6]

Explanation: Potassium Hexacyanoferrate (II), with the formula K4[Fe(CN)6], is an inorganic compound where iron is in the +2 oxidation state and is coordinated with six cyanide (CN) ions. Each potassium ion balances the negative charge of the complex. Option A correctly reflects this structure.Option B is incorrect as it represents Potassium Hexacyanoferrate (III), where iron is in the +3 state. Options C, D, and E contain incorrect ligands or metal ions, which do not represent Potassium Hexacyanoferrate (II).

Q63. Natural Gas (Sui Gas) gas contains _% of Nitrogen in its composition.

• A. 1.05
• B. 0.28
• C. 3.88✓
• D. 0.02
• E. 0.17

Explanation: Natural Gas, including Sui Gas, typically contains around 3.88% nitrogen. This trace element is present in small amounts compared to the primary components like methane. Options A, B, D, and E represent lower percentages that do not accurately reflect the nitrogen content in natural gas. Knowing the typical composition of natural gas can help identify the correct percentage of nitrogen.

Q64. Hexadecanoic acid is IUPAC name of:

• A. Stearic acid
• B. Palmitic acid✓
• C. Butyric acid
• D. Formic acid
• E. Valeric acid

Explanation: The correct answer is Palmitic acid, which is known as hexadecanoic acid in IUPAC nomenclature. This indicates a saturated fatty acid with a 16-carbon chain. Stearic acid, with 18 carbons, corresponds to octadecanoic acid. Butyric acid, valeric acid, and formic acid have 4, 5, and 1 carbon atoms respectively, thus do not match the IUPAC name hexadecanoic acid.

Q65. Which of the following factor/s affect the rate of reaction?

• A. Concentration of reactants
• B. Nature of reactant and temperature
• C. Presence of catalyst
• D. Radiation and Surface area of reactants
• E. All of the given options✓

Explanation: The rate of a chemical reaction is influenced by several key factors: the concentration of reactants affects how often particles collide; the nature of reactants determines the ease of reactions; temperature affects particle energy and collision frequency; catalysts offer a pathway with lower activation energy; radiation can add energy to the system; and increased surface area allows more particles to interact. Each option listed contributes to the understanding of how reaction rates are influenced, making Option E, 'All of the given options,' the correct choice as it encompasses all these factors.

Q66. The dipole moment of NH3 in coulombs metre is:

• A. 5.002 x 10-30✓
• B. 5.002 x 1030
• C. 6.137 x 10-30
• D. 3.436 x 10-30
• E. 3.436 x 1030

Explanation: The correct dipole moment of an ammonia (NH3) molecule is approximately 1.47 Debye (D). To convert this to coulombs meter (C·m), the conversion factor is 1 D = 3.34 x 10-30 C·m. Therefore, 1.47 D x 3.34 x 10-30 C·m/D = 4.91 x 10-30 C·m, which rounds to approximately 5.002 x 10-30 C·m. The other options either miscalculate this conversion or incorrectly represent the magnitude.

Q67. Radius of Cl atom is _ and Cl- ion is _ .

• A. 0.99 Å …. 1.81 Å✓
• B. 1.57 Å …. 0.95 Å
• C. 0.99 Å …. 0.99 Å
• D. 1.81 Å …. 0.99 Å

Explanation: Anions, like Cl-, have more electrons than protons, resulting in decreased nuclear attraction on the outermost electrons. This leads to increased electron repulsion and an expanded electron cloud, making the anion larger than its parent atom. Therefore, the radius of a Cl- ion (1.81 Å) is larger than that of a Cl atom (0.99 Å). Other options suggest incorrect relationships between the sizes of the Cl atom and the Cl- ion, misunderstanding the effects of electron repulsion and nuclear attraction.

Q68. Why the BCl3 molecule is planar, whereas the PH3 molecule is pyramidal/

• A. The boron atom has no d electron available for bonding
• B. The covalent radius of phosphorus is greater than that of boron
• C. The covalent radius of chlorine is greater than that of hydrogen
• D. The boron atom in BCl3 has six electrons in its valence shell, whereas the phosphorus atom has eight✓

Explanation: The correct answer is that the boron atom in BCl3 has six electrons in its valence shell, while the phosphorus atom in PH3 has eight. BCl3 is trigonal planar because boron forms three covalent bonds, resulting in a symmetrical distribution of electrons with no lone pairs. In contrast, PH3 is pyramidal because the lone pair on phosphorus repels the bond pairs, distorting the geometry. This causes a deviation from planarity, leading to a pyramidal shape for PH3. The other options are incorrect because they either do not address the key reason for the difference in molecular geometry (such as the absence of d electrons or differences in covalent radii) or they focus on atomic size rather than electron pair arrangement around the central atom.

Q69. The diagram illustrates the energy chage of a set of reactions. Which of the following statement/s is/are correct?

• A. The enthalpy change for reaction P → R is -33 kJ.mol-1
• B. The enthalpy change for the transformations S → P will be +42 kJ.mol-1
• C. The enthalpy change for the transformation R → Q will be endothermic✓
• D. Data is insufficient

Explanation: The correct answer is Option B: The enthalpy change for the transformations S → P will be +42 kJ.mol-1. This is deduced from the energy diagram, which clearly indicates this value. Option A is incorrect because the diagram provides a different value for P → R. Option C is also incorrect as the diagram shows R → Q as exothermic, not endothermic. Finally, Option D is incorrect because the energy diagram provides sufficient data to calculate the enthalpy changes for the specified reactions.

Q70. How many isomeric compounds will be obtained when di-substituted benzene is prepared from its momo substituted benzene?

• A. 1
• B. 2
• C. 3✓
• D. 4
• E. 5

Explanation: Di-substituted benzene refers to a benzene ring with two substituents. When creating di-substituted benzene from a mono-substituted benzene, the substituents can occupy different relative positions on the ring. The three possible isomers are: ortho (1,2-), meta (1,3-), and para (1,4-). These positions on the benzene ring lead to three distinct compounds. The other options are incorrect because they either underestimate or overestimate the number of possible isomers.

Q71. Ali pushes a toy car, initially at rest, towards Javed by exerting a constant horizontal force ‘F’ of magnitude 10 N through a distance of 2 metres. How much work is done on the toy car?

• A. 5 J
• B. 10 J
• C. 15 J
• D. 20 J✓
• E. 25 J

Explanation: The correct answer is 20 J. The work done on an object can be calculated with the formula W = F × d, where 'W' is the work done, 'F' is the force applied, and 'd' is the distance over which the force is applied. Here, the force (F) is 10 N and the distance (d) is 2 metres. Thus, W = 10 N × 2 m = 20 J. Options A, B, C, and E are incorrect because they either misapply the formula or use incorrect values for force or distance.

Q72. Calculate the change in gravitational potential energy when a 9000 N life moves from ground level to the top of a building 400 m above the ground level?

• A. 1.2 x 102 J
• B. 2.3 x 102 J
• C. 3.6 x 106 J✓
• D. 4.6 x 109 J
• E. 5.9 x 107 J

Explanation: The correct answer is 3.6 x 106 J. Gravitational potential energy is calculated using the formula PE = mgh, where m is the mass (in this case, the weight, which is 9000 N), g is the acceleration due to gravity (standard 9.8 m/s², but incorporated into the weight here), and h is the height (400 m). Thus, PE = 9000 * 400 = 3600000 J or 3.6 x 106 J.Options A and B are incorrect because they are significantly lower than the expected value and likely result from miscalculations. Option D is incorrect because the value is excessively high, suggesting a misinterpretation of the formula. Option E is also incorrect as it is higher than the correct answer, indicating a potential error in calculation or unit conversion.

Q73. A train is approaching a station at 90 km/h sounding a whistle of frequency 1000 Hz. What will be the apparent frequency of the whistle as heard by a listener sitting on the platform?(Speed of sound= 340 m/s)

• A. 9079.4 Hz
• B. 1079.4 Hz✓
• C. 1171.1 Hz
• D. 1311.9 Hz
• E. 1715.7 Hz

Explanation: When the train is approaching the station at 90 km/h, the apparent frequency heard by the listener can be calculated using the formula: f = [v / (v - u)] fo, where v is the speed of sound and u is the speed of the train. Plugging in the given values, we get 1079.36 Hz as the correct answer. The other options are incorrect because they do not correctly apply the Doppler effect formula or use the given values.

Q74. What will be the spring constant, when a body of mass 0.5 kg is attached to a spring and placed on a horizontal frictionless table. The spring is stretched 40 cm when a force of 10 N is applied.

• A. 5 N/m
• B. 10 N/m
• C. 20 N/m
• D. 25 N/m✓
• E. 35 N/m

Explanation: The spring constant can be found using Hooke's Law, which is F = kx, where F is the force applied, k is the spring constant, and x is the displacement from equilibrium (in meters). Given that the force F is 10 N and the displacement x is 0.4 m (since 40 cm = 0.4 m), we can substitute these values into the formula to solve for the spring constant k:10 N = k * 0.4 mk = 10 N / 0.4 m = 25 N/mTherefore, the spring constant is 25 N/m. The other options are incorrect because they result from either incorrect calculations of the displacement or incorrect applications of Hooke's Law.

Q75. Identify the example/s of thin films:I. Soap bubblesII. Thin Layer of oil floating on waterIII. Flowing of honey

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

Explanation: A thin film is a layer of material that is thin enough to create light interference patterns, resulting in visible color changes. Soap bubbles and a thin layer of oil on water are classic examples because they both exhibit these light interference effects. Flowing honey, on the other hand, is opaque and does not form a thin enough layer to create such patterns, which is why it is not considered a thin film.

Q76. An object 4 cm high is located 10 cm from the converging lens, whose focal length is 20 cm. The image that will be formed is:

• A. Virtual
• B. Erect
• C. Real
• D. Both Virtual and Erect✓
• E. Both Erect and Real

Explanation: The object is placed 10 cm from a converging lens with a focal length of 20 cm, meaning it is inside the focal point. For converging lenses, when the object is placed between the focal point and the lens, the image formed is virtual and erect. Thus, the correct answer is 'Both Virtual and Erect'.Options stating the image is real or simply erect without being virtual are incorrect because a real image would be inverted, and a solely erect image implies it must also be virtual.

Q77. The energy that flows from a high-temperature object to a low-temperature object is called:

• A. Electricity
• B. Sound
• C. Solar energy
• D. Heat✓
• E. Hydro energy

Explanation: Heat is the correct answer because it specifically refers to the transfer of energy from a high-temperature object to a low-temperature object. This process occurs when there is a temperature difference between two objects or systems. Other options like electricity, sound, solar energy, and hydro energy refer to different types of energy that are not directly related to temperature differences. Electricity involves electric charge flow, sound involves vibrations, solar energy comes from the sun, and hydro energy is derived from water movement.

Q78. The amount of charge that flows through a given cross-section of a wire in one second, if there is a steady current of 1 ampere in the wire is known as:

• A. Electric Potential
• B. Coulomb✓
• C. Joule
• D. Flux Density
• E. Electron Volt

Explanation: The correct answer is 'Coulomb'. A current of 1 ampere indicates that 1 coulomb of charge flows through a cross-section of a wire every second, based on the formula I=Q/t where I is the current in amperes, Q is the charge in coulombs, and t is the time in seconds. The other options represent different physical quantities: 'Electric Potential' (volts), 'Joule' (energy), 'Flux Density' (magnetic fields), and 'Electron Volt' (energy, not charge).

Q79. Two opposite point charges each of magnitude ‘q’ are separated by a distance 2d. What is the electric potential at a point ‘p’ midway between them?

• A. 0✓
• B. 10
• C. 20
• D. 30
• E. 40

Explanation: The electric potential at a point due to a point charge is given by V = kq/r, where k is Coulomb's constant, q is the charge, and r is the distance from the charge to the point of interest. At point 'p', which is equidistant from both charges, the potential due to each charge is equal in magnitude but opposite in sign (since one charge is positive and the other is negative). Hence, they cancel each other out, resulting in a net electric potential of zero.The other options propose non-zero values for the potential, which overlook the fundamental principle that potentials from equal and opposite charges at equal distances will cancel each other out.

Q80. Two capacitors C1 (6µF) and C2 (12µF) are in series across 180 volts d.c. supply. Calculate the charges on C1 and C2

• A. 720 x 10-6 C ….. 720 x 10-6 C✓
• B. 920 x 10-6 C …. 730 x 10-6 C
• C. 660 x 10-6 C …. 480 x 10-6 C
• D. 440 x 10-6 C …. 770 x 10-6 C
• E. 910 x 10-6 C …. 750 x 10-6 C

Explanation: In a series circuit, the same charge is stored across each capacitor. The equivalent capacitance Ceq is given by the formula 1/Ceq = 1/C1 + 1/C2. For C1 = 6µF and C2 = 12µF, the equivalent capacitance Ceq is 4µF. The total charge Q can be calculated by Q = Ceq × V, where V is the voltage. Therefore, Q = 4µF × 180V = 720µC or 720 x 10-6 C. This charge is the same for both capacitors in series, making Option A correct. Other options incorrectly assume different charges for C1 and C2, which contradicts the properties of capacitors in series.

Q81. 1 x 107 electrons pass through a conductor in 1.0 µs. Find the current in ampere flowing through the conductor. Electronic charge is 1.6 x 10-19 C.

• A. 1.6 x 10-6 A✓
• B. 3.6 x 10-6 A
• C. 5.6 x 10-6 A
• D. 7.6 x 10-6 A
• E. 9.6 x 10-6 A

Explanation: To find the current flowing through the conductor, we use the formula I = Q/t, where I is the current, Q is the total charge, and t is the time. The total charge Q can be calculated by multiplying the number of electrons (1 x 107) by the charge of each electron (1.6 x 10-19 C). This gives Q = (1 x 107) x (1.6 x 10-19 C) = 1.6 x 10-12 C. Given that the time t = 1.0 µs = 1.0 x 10-6 s, the current I = Q/t = (1.6 x 10-12 C) / (1.0 x 10-6 s) = 1.6 x 10-6 A. Thus, Option A is correct. The other options reflect incorrect calculations of either the charge or the time interval.

Q82. An electric device has a resistance of 300 Ω, find the current in it when it is connected to a 450 volt source?

• A. 9.5 A
• B. 7.5 A
• C. 5.5 A
• D. 3.5 A
• E. 1.5 A✓

Explanation: The correct answer is 1.5 A. According to Ohm's Law, which states that V = IR, you can find the current (I) by rearranging the formula to I = V/R. Plugging in the values from the question, I = 450V / 300Ω = 1.5 A. The other options are incorrect due to miscalculations or misapplications of Ohm's Law.

Q83. A battery of 12 volts is connected to two resistors of 6 Ω and 4Ω joined together in series. Find the potential drop across each resistor respectively?

• A. 3.7 V …. 2.5 V
• B. 5.9 V …. 3.1 V
• C. 7.2 V …. 4.8 V✓
• D. 8.1 V …. 5.3 V
• E. 9.7 V …. 7.7 V

Explanation: To solve this problem, use Ohm's Law, which states V = IR. The total voltage (V) is 12 V, and the total resistance (R) is 6 Ω + 4 Ω = 10 Ω. Thus, the current (I) is V/R = 12 V / 10 Ω = 1.2 A.The potential drop across each resistor is calculated by multiplying the current by the resistance of each resistor. For the 6 Ω resistor, the voltage drop is 1.2 A x 6 Ω = 7.2 V. For the 4 Ω resistor, it is 1.2 A x 4 Ω = 4.8 V.Options A, B, D, and E are incorrect as they do not correctly apply the formula V = IR to find the correct voltage drops across each resistor.

Q84. The sum of the products of the tangential component of magnetic field of induction and the length of an element of a closed curve taken in the magnetic field is µ0 times the current which passes through the area bounded by the curve is known as:

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

Explanation: The question describes Ampere’s Law, which states that the line integral of the magnetic field around a closed path is equal to µ0 times the current passing through the area enclosed by the path. This is a fundamental concept in electromagnetism. The other options, such as Faraday’s Law, Coulomb’s Law, Newton’s Law, and Ohm’s Law, pertain to different phenomena in physics and do not match the description provided in the question.

Q85. If two coils are close together, then a changing current in one (the primary) sets up a changing magnetic field in the other (the secondary) and so induces an e.m.f. In it. This effect is known as:

• A. Simple induction
• B. Self induction
• C. Mutual induction✓
• D. Relative induction
• E. Non-Relative induction

Explanation: Mutual induction occurs when a changing current in one coil produces a changing magnetic field that induces an electromotive force in a nearby coil. This effect is utilized in devices like transformers. The incorrect options are either not real terms (Simple induction, Relative induction, Non-Relative induction) or describe different phenomena (Self induction refers to induction within the same coil).

Q86. What will be the value of shunt resistance that must be connected across a galvanometer of 50.0 Ω resistance which gives full-scale deflection with 2.0 mA current so as to convert it into an ammeter of range 10.0 A?

• A. 5.07 Ω
• B. 4.09 Ω
• C. 3.05 Ω
• D. 0.01 Ω✓
• E. 2.01 Ω

Explanation: The correct shunt resistance is 0.01 Ω. To determine this, first calculate the voltage across the galvanometer when it shows full-scale deflection: V = I x R = 2 mA x 50 Ω = 0.1 V. To convert this galvanometer into an ammeter with a 10 A range, the total resistance must allow for 10 A to create the same 0.1 V across the galvanometer, which implies R = V/I = 0.1 V / 10 A = 0.01 Ω. This means the shunt resistor needs to provide a very low resistance path to allow most of the current to bypass the galvanometer. Therefore, the correct answer is 0.01 Ω. Other options are incorrect because they would not permit the galvanometer to measure the larger current accurately.

Q87. When an external voltage is applied to the junction in such a direction that it cancels the potential barrier, thus permitting current flow, is known as:

• A. Forward Biasing✓
• B. Reverse Biasing
• C. Intermediate Biasing
• D. Simple Biasing
• E. Collective Biasing

Explanation: The correct answer is Forward Biasing. When a p-n junction is forward biased, the external voltage is applied in such a way that it reduces or cancels the potential barrier. This reduction in the barrier allows charge carriers to move across the junction, thereby permitting current flow. In contrast, Reverse Biasing increases the potential barrier, preventing current flow. The terms Intermediate Biasing, Simple Biasing, and Collective Biasing are not standard terms in semiconductor physics and do not accurately describe any conditions affecting the potential barrier or current flow in p-n junctions.

Q88. Identify the postulate/s of the special theory of relativity:I. There is no preferred or absolute inertial frame of reference i.e. all the interstitial frames are equivalent for the description of all physical law.II. The speed of light in a vacuum is the same for all observers in uniform translational relative motion and is independent of the motion of the observer and the source.

• A. I only
• B. II only
• C. I and II✓
• D. Neither I nor II

Explanation: The special theory of relativity is based on two fundamental postulates proposed by Albert Einstein. The first postulate states that there is no preferred or absolute inertial frame of reference, meaning that the laws of physics are the same in all inertial frames. This implies that all inertial frames are equivalent for the formulation of physical laws. The second postulate asserts that the speed of light in a vacuum is constant and is the same for all observers, regardless of the motion of the light source or the observer. Therefore, both statements I and II are correct. Option D is incorrect because both postulates are indeed valid and integral to the theory.

Q89. Ruby is a crystal of:

• A. Al2O3:Cr✓
• B. PbO2
• C. KO2
• D. CO2
• E. SO4

Explanation: A ruby is a red gemstone and a variety of the mineral corundum, which is composed primarily of aluminium oxide (Al2O3). The red color of ruby is due to trace amounts of chromium (Cr) substituting for aluminium in the crystal structure, making the correct chemical representation Al2O3:Cr. None of the other options represent compounds related to ruby's composition. PbO2, KO2, CO2, and SO4 are chemically distinct and unrelated to the mineral corundum.

Q90. Identify the property/ies of a good coolant:I. It should have as little effect on neutrons as possible.II. It should not induce any chemical effect with other materials in contact with the system.III. The coolant should not break up under the effect of radiations.

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

Explanation: A good coolant in a reactor should fulfill all three criteria: it should not significantly affect neutrons (I), to avoid altering the nuclear reaction; it should not chemically react with system materials (II), which prevents corrosion and damage; and it should withstand radiation without degrading (III), ensuring long-term effectiveness. Options that include only one or two of these properties neglect important aspects of coolant function, making them insufficient.

Q91. A positively charged particle with mass one-fourth and charge one half of an α- particle is:

• A. Neutron
• B. Proton✓
• C. Beta particle
• D. Gamma particle
• E. Atomic Nucleus

Explanation: An alpha particle has a charge of +2 and a mass of approximately 4 atomic mass units. The described particle has a charge that is half of an alpha particle's, which is +1, and a mass that is one-fourth of an alpha particle's, which is 1 atomic mass unit. These properties match that of a proton. Neutrons are neutral, beta particles are negatively charged, gamma particles have no charge or mass, and an atomic nucleus is a composite of particles, not a single particle.

Q92. Find the angle between two forces of equal magnitude when the magnitude of their resultant is also equal to the magnitude of either of these forces:

• A. 30˚
• B. 45˚
• C. 55˚
• D. 65˚
• E. 120˚✓

Explanation: When two forces of equal magnitude act at an angle, the magnitude of their resultant can be found using the parallelogram law of vector addition. For the resultant to be equal to the magnitude of either of the forces, they must be arranged such that the angle between them is 120˚. This is a result of the law of cosines applied to the situation where the resultant magnitude equals one of the forces: R = 2Fcos(θ/2). When θ = 120˚, cos(60˚) = 0.5, thus satisfying the condition.The incorrect options suggest angles where the resultant magnitude would not match the individual forces' magnitude due to their trigonometric relationships.

Q93. Find the projection of vector A= 2i -8j + k in the direction of the vector B= 3i- 4j- 12k.

• A. 1
• B. 2✓
• C. 5
• D. 7
• E. 9

Explanation: To find the projection of vector A = 2i - 8j + k onto vector B = 3i - 4j - 12k, first calculate the dot product A.B. This equals (2)(3) + (-8)(-4) + (1)(-12) = 6 + 32 - 12 = 26. The magnitude of vector B, ||B||, is calculated as √(3² + (-4)² + (-12)² = 9 + 16 + 144 = 169), which is 13. The unit vector in the direction of B is B̂ = (3i - 4j - 12k)/13.The projection of A onto B is given by (A.B) / ||B|| = 26 / 13 = 2. This confirms that the correct answer is 2. The other options result from incorrect calculations or misunderstanding the projection formula.

Q94. A truck starts from rest and moves with a constant acceleration. During the 5th second of its motion, it covers a distance of 36 meters. What is the acceleration of the truck?

• A. 8 m/s2✓
• B. 12 m/s2
• C. 16 m/s2
• D. 20 m/s2
• E. 24 m/s2

Explanation: To determine the acceleration, we use the formula for the distance covered during a specific second of motion under constant acceleration. In this case, the formula for the distance covered during the nth second is: s = u + (a/2)(2n-1), where u is the initial velocity (0 m/s since the truck starts from rest). For the 5th second, the distance covered is 36 meters. Solving 36 = (0) + (a/2)(9) gives us an acceleration (a) of 8 m/s2.Option A correctly calculates the acceleration as 8 m/s2. Options B, C, D, and E propose higher accelerations that are not consistent with the distance covered during the 5th second.

Q95. One Kilogram x One m/s2=?

• A. 0.5 Newtons
• B. 1 Newton✓
• C. 2.5 Newtons
• D. 5 Newtons
• E. 7.5 Newtons

Explanation: The correct answer is 1 Newton. According to Newton's second law, force (F) is calculated by multiplying mass (m) by acceleration (a), expressed as F = m * a. In this question, the mass is 1 kilogram and the acceleration is 1 meter per second squared, resulting in a force of 1 Newton. Other options are incorrect as they do not accurately reflect the product of the given mass and acceleration.

Q96. A ball is thrown with a speed of 30 m/s in a direction 30˚ above the horizon. What is the height to which it rises?

• A. 9.5 m
• B. 11.5 m✓
• C. 13.5 m
• D. 15.5 m
• E. 17.5 m

Explanation: To find the maximum height, we need to use the vertical component of the initial velocity. The vertical velocity, vy0, can be calculated as v0sin(θ), where v0 is the initial speed (30 m/s) and θ is the angle of projection (30˚). Therefore, vy0 = 30sin(30˚) = 15 m/s. The maximum height, h, can be found using the kinematic equation: vy2 = vy02 - 2gh, where vy is 0 m/s at the maximum height. Solving gives h = 11.5 m. Other options result from errors in applying these calculations, such as incorrect trigonometric function usage or neglecting gravitational acceleration.

Q97. Saad has a mass of 80 kg when resting on the ground at the equator. What will be the centripetal acceleration on Saad if the radius of the earth is 6.4 x 106 m.

• A. 2.21 x 10-2 m/s2
• B. 3.37 x 10-2 m/s2✓
• C. 5.91 x 10-2 m/s2
• D. 7.96 x 10-2 m/s2
• E. 9.99 x 10-2 m/s2

Explanation: The centripetal acceleration is calculated using the formula a = v2/r, where v is the linear speed at the equator and r is the radius of the Earth. The speed is determined by the distance traveled in one day, which is the Earth's circumference, divided by the time period of 24 hours (converted to seconds). The correct calculation gives a speed of approximately 465 m/s, leading to a centripetal acceleration of 3.37 x 10-2 m/s2. The other options are incorrect due to errors in calculating either the speed or the application of the formula.

Q98. The gravitational force between two bodies does not depend upon?

• A. Size of the bodies
• B. Their separation
• C. The product of their masses
• D. The sum of their masses✓
• E. Both Size and Separation of the bodies

Explanation: The gravitational force between two bodies is calculated using the formula F = G(M1M2)/R2, where F is the force, G is the gravitational constant, M1 and M2 are the masses of the two bodies, and R is the distance between their centers. The force depends on the product of the masses (M1M2) and the distance (R), but not on the sum of their masses. Therefore, the sum of the masses does not influence the gravitational force, making Option D the correct answer. Option A is incorrect because size is not a factor in the gravitational formula. Option B is incorrect as separation does affect the force. Option C is incorrect because the product of the masses is a determinant of the force. Option E is incorrect because, although separation matters, size does not.

Q99. “A body at rest or moving with uniform velocity has zero acceleration. From Newton’s law of motion, the vector sum of all forces acting on it must be zero.” This is _ condition of equilibrium.

• A. First✓
• B. Second
• C. Third
• D. Fourth
• E. Fifth

Explanation: The correct answer is the 'First' condition of equilibrium. According to Newton's first law of motion, a body at rest or moving with uniform velocity has no net force acting on it, indicating zero acceleration. This is the first condition of equilibrium, which requires the vector sum of all forces acting on a body to be zero for it to maintain its state of motion or rest. The second condition of equilibrium, not applicable here, concerns the absence of net torque to prevent rotational motion. Options 'Third', 'Fourth', and 'Fifth' are distractors as they do not pertain to recognized conditions of equilibrium in physics.

Q100. The time that is referred to as the rotation of the earth about its axis is known as:

• A. Scalar time
• B. Vector time
• C. Universal time
• D. Half time
• E. Rotation time✓

Explanation: The correct answer is Rotation time. Earth's rotation time refers to the period it takes to spin once around its own axis, which results in the 24-hour day-night cycle. This is distinct from the concept of 'revolution,' which relates to Earth's orbit around the Sun, taking approximately 365.25 days. The other options, such as Scalar time and Vector time, are not applicable to Earth's rotation, while Universal time is a time standard rather than a description of Earth's motion. Half time is unrelated to this context entirely.