Sindh Mcat Nts 2011 Lumhs — Solved Past Paper with Answers

Q1. Identify the word or phrase that needs to be changed for the sentence to be correct:Many of the new plastics is made from oil.

• A. Of
• B. New
• C. Is made✓
• D. Oil
• E. No error

Explanation: The phrase, ‘is made’ needs to be changed because plastics acts as a plural noun whereas ‘is’ is used for a singular noun. The correct sentence will be ; “Many of the new plastics are made from oil.”

Q2. Identify the word or phrase that needs to be changed for the sentence to be correct:Do not let your radio blare so as to disturbs your neighbours.

• A. Do not
• B. Blare
• C. To disturbs✓
• D. Neighbours
• E. No error

Explanation: The phrase, ‘to disturbs’ needs to be changed because the neighbours is plural whereas singular form of verb, ‘disturbs’ i.e ‘disturb’ is used. The correct sentence will be ; “Do not let your radio blare so as to disturb your neighbours.”

Q3. Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters.SHALLOW:

• A. Deep✓
• B. Dear
• C. Thin
• D. Clean
• E. Pure

Explanation: The word SHALLOW describes something that has little depth or extent downward. Its antonym is Deep, which means extending far down from the top or surface. Therefore, the correct answer is Deep. The other options do not relate to depth: Dear pertains to affection, Thin refers to breadth rather than depth, Clean is about purity or lack of dirt, and Pure refers to being unmixed, none of which oppose the concept of shallowness.

Q4. Choose the lettered word or phrase that is most nearly opposite in meaning to the word in capital letters.FAULT:

• A. Error
• B. Mistake
• C. Blunder
• D. Accurate✓
• E. Slip

Explanation: The word 'FAULT' refers to a mistake or error. Its opposite is 'Accurate,' which means free from mistakes or errors, indicating correctness and precision. Options such as 'Error,' 'Mistake,' 'Blunder,' and 'Slip' are all synonymous with 'FAULT,' as they all imply some form of mistake or error, which does not make them suitable opposites.

Q5. Choose the word most similar in meaning to the capitalised ones.ENGULF:

• A. Ingest✓
• B. Show
• C. Wipe
• D. Clarify
• E. Waste

Explanation: Engulf means to eat or swallow (something) whole, ingest being its synonym means to take (food, drink, or another substance) into the body by swallowing or absorbing it.

Q6. Choose the word most similar in meaning to the capitalised ones.STUMBLE:

• A. Walk
• B. Fall✓
• C. Study
• D. Acquire
• E. Compose

Explanation: The word 'STUMBLE' implies a momentary loss of balance, often leading to a fall. Therefore, the word most similar in meaning is 'Fall,' which also involves losing one's balance and collapsing. 'Walk' involves controlled, balanced movement, 'Study' pertains to learning, 'Acquire' refers to obtaining something, and 'Compose' involves creating or arranging, none of which relate to losing balance or control.

Q7. Read the following passage to answer the following question:The steam engine improved in efficiency during the nineteenth century and in 1843Stringfellow, an Englishman, achieved a remarkable technical and scientific triumphby getting a model aeroplane, powered by a small steam engine, to fly. However, itnever seemed likely - that a steam engine fitted to an aeroplane would ever get itsown weight and that of a man off the ground. Unlike the airship and the balloon,which are lighter than air, the aeroplane is a heavier-than-air machine which mustmove rapidly if it is to fly at all. Consequently it must have an engine that is verypowerful in proportion to its weight.It can be inferred from the passage that airship and balloon are:

• A. Heavier than air
• B. Heavier than aeroplane
• C. Lighter than aeroplane✓
• D. Of the same weight as the air
• E. Of the same weight as the aeroplane

Explanation: It can be inferred from the given passage that airships and air balloons are lighter than air whereas aeroplanes are heavier than air. Therefore airships and air balloons are lighter than aeroplanes. Air ships, air balloons < air < aeroplanes

Q8. Read the following passage to answer the following question:The steam engine improved in efficiency during the nineteenth century and in 1843. Stringfellow, an Englishman, achieved a remarkable technical and scientific triumph by getting a model aeroplane, powered by a small steam engine, to fly. However, it never seemed likely - that a steam engine fitted to an aeroplane would ever get its own weight and that of a man off the ground. Unlike the airship and the balloon, which are lighter than air, the aeroplane is a heavier-than-air machine which must move rapidly if it is to fly at all. Consequently it must have an engine that is very powerful in proportion to its weight.The word “its” in the passage refers to the:

• A. Balloon
• B. Steam engine✓
• C. Man
• D. Airship
• E. None of these options

Explanation: The word 'its' in the passage refers to the 'steam engine.' The passage discusses the necessity for the steam engine to have a high power-to-weight ratio, which is crucial for heavier-than-air machines like aeroplanes. The other options, such as 'balloon,' 'man,' and 'airship,' do not fit the context of requiring engine power in proportion to weight. Balloons and airships are lighter-than-air and do not rely on such engines, and 'man' refers to the load rather than being an engine component.

Q9. Complete the sentence by choosing the most appropriate word, from the given lettered choices (A to E) below each.It should be _ karachi than it is here.

• A. Warms in
• B. Warm in
• C. Warmest in
• D. Warmer in✓
• E. Warmed in

Explanation: The correct answer is 'Warmer in' because 'warmer' is the comparative form of 'warm,' used to compare two places: Karachi and 'here.' Comparatives are typically used with 'than' to highlight differences between two entities. The other options either do not fit the grammatical structure for comparison or are incorrectly tense-marked for the context of this sentence.

Q10. Complete the sentence by choosing the most appropriate word, from the given lettered choices (A to E) below each.The municipality prohibits parking _ the main road.

• A. At
• B. On✓
• C. Off
• D. In over
• E. None

Explanation: The correct answer is 'on' because it is the preposition used to describe something being placed or located on a surface. In the sentence, 'The municipality prohibits parking on the main road,' 'on' appropriately describes the position of the cars in relation to the road. The other options are incorrect because: 'At' implies a specific point rather than a surface; 'Off' suggests removal or away from a surface; 'In over' is not a valid preposition in this context; and 'None' incorrectly implies that no suitable preposition is available.

Q11. White blood cells picking up foreign bodies from the blood stream is an example of:

• A. Pinocytosis
• B. Exocytosis
• C. Phagocytosis✓
• D. Osmosis
• E. None

Explanation: The correct answer is Phagocytosis. This is the process by which certain cells, such as white blood cells, ingest or engulf other cells or particles, including foreign bodies. White blood cells use phagocytosis to clear the bloodstream of pathogens and debris. Pinocytosis and osmosis do not involve engulfing particles; exocytosis is the expulsion of materials, and 'None' is incorrect as phagocytosis is the appropriate process.

Q12. Arbiruses causes1. Encephalitis 2. Yellow fever3. Dengue

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

Explanation: Arboviruses, or arthropod-borne viruses, are transmitted by vectors such as mosquitoes and ticks. These viruses can cause a variety of diseases in humans. Encephalitis is an inflammation of the brain often caused by arboviruses. Yellow fever and dengue are also viral infections transmitted by mosquitoes belonging to the arbovirus group. Therefore, all the listed diseases (1, 2, and 3) are indeed caused by arboviruses. Options A, B, C, and D are incorrect because they do not account for all the diseases caused by arboviruses.

Q13. The most common method of bacterial reproduction is:

• A. Fission✓
• B. Transduction
• C. Endospore
• D. Conjugation
• E. Transformation

Explanation: The correct answer is Fission. Bacteria are prokaryotic organisms that reproduce asexually. The most common method of bacterial reproduction is binary fission, in which a single cell divides into two genetically identical daughter cells. This process allows for rapid multiplication.Other options listed, such as transduction, conjugation, and transformation, are methods of genetic exchange rather than reproduction. Endospore formation is a survival strategy, not a method of reproduction.

Q14. The number of protist phyla is:

• A. 1
• B. 3
• C. 5
• D. 7
• E. 9✓

Explanation: The number of protist phyla is generally considered to be more than 9, though the exact number is subject to scientific debate and ongoing research. Protists are a diverse group of eukaryotic organisms, and their classification has been challenging due to the diversity and complexity of these organisms. Recent studies and classification systems may propose a range from about 12 to over 70 phyla, but the commonly accepted number is at least 9. The options less than 9 do not reflect the broad diversity within the protist kingdom, while option 9 aligns with current scientific consensus.

Q15. Which of the following is an example of cloning;1. Identical twins in humans 2. Asexual reproduction in plants3. Tumor

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

Explanation: 1.Individual human cloning occurs naturally in the case of identical twins, when two individuals develop from a single fertilized egg.2.Cloning is a natural form of reproduction – an asexual type, to be precise. It is the reproduction method used by many organisms, such as plants, fungi, and bacteria.3.The human tumor cloning system is a soft agar technique which allows the growthof human tumors in vitro.So above written all the examples are part of cloning.

Q16. Holoenzyme consists of:

• A. Apoenzyme and prosthetic group✓
• B. Pro enzyme and Prosthetic group
• C. Co enzyme and Prosthetic group
• D. Pro enzyme and apo enzyme
• E. Apo enzyme and co enzyme

Explanation: A holoenzyme is the active form of an enzyme, consisting of an apoenzyme, which is the protein part, and a prosthetic group, which is a non-protein component that is tightly bound to the enzyme. This combination allows the enzyme to function properly. The other options are incorrect because they either involve inactive forms of enzymes (proenzymes) or refer to components that do not form a holoenzyme (coenzymes instead of prosthetic groups).

Q17. Excess water is forced out in the form of droplets through

• A. Stomata
• B. Cuticle
• C. Hydathodes✓
• D. Lenticles
• E. All of the above

Explanation: Excessive water is removed from the plant body by the process of transpiration. Hydathodes are special glands that remove water in the form of droplets.

Q18. Which of the following statement is correct:

• A. Aldosterone is secreted by adrenal medulla
• B. Parathormone is secreted by thyroid gland
• C. Vasopressin is secreted by posterior pituitary gland✓
• D. Aldosterone increases reabsorption of potassium ions in the nephron.
• E. Parathormone increases the reabsorption of sodium ions in nephron

Explanation: a. Aldosterone is secreted by adrenal cortex so option a is wrongb. Parathormone is secreted by parathyroid gland so option b is wrongc. It is a fact so c option is correct. Vasopressin along with oxytocin are secreted by posterior pituitaryd. Option d is correct as aldosterone is concerned with sodium ion reabsorption and excretion of potassium ione. Parathormone increases the reabsorption of Ca ions so last option is incorrect

Q19. The total number of bones in a human skeleton is

• A. 207
• B. 206✓
• C. 208
• D. 205
• E. 203

Explanation: The correct answer is 206. An adult human skeleton typically consists of 206 bones. This includes the bones of the axial skeleton (skull, vertebral column, rib cage) and the appendicular skeleton (limbs and girdles). Other options are incorrect as they either overestimate or underestimate the standard count of bones in a typical adult human skeleton.

Q20. Each myosin filament is surrounded by :

• A. 5 actin filaments
• B. 6 actin filaments✓
• C. 10 actin filaments
• D. 12 actin filaments

Explanation: Arrangement in sarcomere=1 myosin filament surrounded by 6 actin filaments.

Q21. The largest gland of the body is

• A. Pancreas
• B. Liver✓
• C. Pituitary gland
• D. Thyroid gland
• E. Parathyroid gland

Explanation: The liver is the largest gland in the human body and serves multiple critical functions including detoxification, protein synthesis, and chemical production for digestion. It is much larger in size compared to other glands like the pancreas, pituitary, thyroid, and parathyroid, which have specific but smaller roles in the body.

Q22. In the process of inspiration _ and _ are involved

• A. Intercostal muscles, diaphragm✓
• B. Deltoid muscles, diaphragm
• C. Trapezius, intercostal muscles
• D. Biceps, triceps
• E. None

Explanation: The correct answer is that the intercostal muscles and the diaphragm are involved in inspiration. The diaphragm is a dome-shaped muscle that contracts and moves downwards to increase the volume of the thoracic cavity, while the intercostal muscles contract to lift the ribs up and out, further expanding the chest cavity. This results in a decrease in pressure inside the lungs, causing air to flow in. Other muscle groups, like the deltoid, trapezius, biceps, and triceps, are not involved in the breathing process, as they are responsible for different types of movements unrelated to respiration.

Q23. Blinking of eye is an example of

• A. Taxes
• B. Reflex✓
• C. Learning
• D. Insight Learning
• E. Imprinting

Explanation: Blinking of eyes is an example of an involuntary reflex action, which occurs automatically without conscious effort to protect the eye from potential harm. Reflex actions are rapid and involve the nervous system. The other options do not describe automatic physiological responses: Taxes relate to economics, Learning and Insight Learning involve conscious processes, and Imprinting is a specific type of learning related to early life experiences.

Q24. Parthenogenesis is a type of reproduction which requires

• A. One parent female✓
• B. One parent male
• C. Two parents
• D. No parents
• E. None of the above

Explanation: Parthenogenesis is a form of asexual reproduction where a new individual is developed from an unfertilized egg. This process requires only one parent, specifically a female, as there is no involvement of male gametes. Organisms such as honey bees, ants, and certain birds can reproduce through parthenogenesis. Other options are incorrect because they either suggest the need for a male parent or no parent at all, which do not align with the concept of parthenogenesis.

Q25. Which of the following is a female sexual defect?

• A. Microcephaly
• B. Polydactyl
• C. Turner's syndrome✓
• D. Klinefelter's Syndrome
• E. Cleft lip and cleft palate

Explanation: Turner's syndrome is a unique condition affecting only females due to the complete or partial absence of one X chromosome, leading to a variety of medical and developmental issues, including those related to sexual development. Microcephaly, polydactyly, and cleft lip/palate are not specifically related to female sexual defects. Klinefelter's syndrome affects males, not females, and involves an extra X chromosome.

Q26. The chromosome number in humans is

• A. 3 pair
• B. 13 pair
• C. 23 pair✓
• D. 33 pair
• E. 43 pair

Explanation: Humans have 23 pairs of chromosomes, totaling 46 chromosomes. This includes 22 pairs of autosomes and one pair of sex chromosomes (XX in females and XY in males). Each parent contributes one chromosome to each pair. Options A, B, D, and E suggest incorrect numbers of chromosome pairs, which do not align with human genetics.

Q27. In down syndrome, the 21st pair of chromosomes:

• A. Lacks one chromosome
• B. Has an extra chromosome attached to it✓
• C. Is missing
• D. Lacks genes
• E. None

Explanation: Down syndrome is caused by trisomy 21, where an individual has three copies of chromosome 21 instead of the usual two. This results from abnormal cell division during the development of the sperm or egg cell. Option B is correct because it specifically describes the presence of an extra chromosome. Options A, C, and D are incorrect as they suggest a deficiency or absence of chromosomes or genes, which do not cause Down syndrome. Option E is incorrect because it suggests no chromosomal abnormality, which contradicts the fundamental cause of Down syndrome.

Q28. Which of the following activities occur during interphase 1. DNA duplication 2. RNA synthesis 3. Volume of the cell roughly doubles

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

Explanation: During interphase, a cell undergoes several critical processes to prepare for division, which include:DNA duplication: Ensures that each daughter cell will receive a complete set of genetic material.RNA synthesis: Production of RNA is necessary for protein synthesis, which supports various cellular functions and growth.Cell growth: The cell increases in size, roughly doubling its volume, to accommodate the resources needed for two daughter cells.Interphase is a collective term for the G1, S, and G2 phases of the cell cycle, during which these processes take place. The incorrect options either omit one or more of these activities, which are all essential during interphase.

Q29. Mendel performed his famous experiment of heredity on

• A. Maize
• B. Bean plants
• C. Garden pea✓
• D. Mirabilis plant
• E. Wheat

Explanation: Mendel conducted his groundbreaking heredity experiments on the garden pea (Pisum sativum). He selected this plant because it had easily observable traits such as flower color and seed shape, which allowed him to derive the fundamental laws of inheritance. The traits in peas are distinct and exhibit simple dominant-recessive relationships, making them ideal for Mendel's study.Other plants, such as maize, bean plants, Mirabilis, and wheat, have since been used in genetic research, but they do not share the same historical significance in Mendel's original experiments. Maize is used in quantitative genetics, bean plants are used in ecological and physiological studies, Mirabilis is known for illustrating incomplete dominance, and wheat is studied for its agricultural and genetic properties.

Q30. A man who is normal for color vision marries a normal heterozygous woman. What is the chance of their son being color blind?

• A. 0%
• B. 25%
• C. 50%✓
• D. 75%
• E. 100%

Explanation: Red-green color blindness is an X-linked recessive condition. For a son to be color blind, he must inherit the Xn chromosome from his mother, as he will inherit the Y chromosome from his father. The mother, being heterozygous (XNXn), has a 50% chance of passing on the Xn chromosome. Therefore, there is a 50% chance that their son will be color blind. The options of 0%, 25%, 75%, and 100% do not accurately reflect the inheritance pattern for this X-linked trait, given the genotypes of the parents.

Q31. Thw enzyme used to seal the sticky ends of DNA restriction fragment is:

• A. Ligase✓
• B. Polymerase
• C. Adenosine deaminase
• D. Trypsin
• E. All

Explanation: DNA ligase is the correct enzyme used to join the sticky ends of DNA restriction fragments. It catalyzes the formation of phosphodiester bonds between adjacent nucleotides, thus enabling the recombination of DNA. Polymerase enzymes, on the other hand, are involved in DNA synthesis. Adenosine deaminase is unrelated to DNA fragment sealing as it functions in purine metabolism. Trypsin is a protein-digesting enzyme and has no role in DNA ligation. Therefore, 'All' is incorrect because not all the listed enzymes have the function of sealing DNA fragments.

Q32. Which of the following statement is FALSE based on Darwins theory of evolution

• A. Natural selection is the driving force of evolution
• B. Favorable genetic variations become more and more common in individuals throughout their lives✓
• C. There is always a tendency of overproduction in a species.
• D. All individuals of a species are not 100% alike
• E. None of the above

Explanation: The correct answer is Option B. Darwin's theory of evolution states that favorable genetic variations become more frequent in a population over generations, not within the lifespan of individuals. Natural selection acts on the genetic variation present in a population, leading to the evolution of traits that are advantageous for survival and reproduction. Option A is true as natural selection is indeed the driving force of evolution. Option C is also true as overproduction is a mechanism that leads to competition and natural selection. Option D is correct because genetic variation among individuals in a species is a fundamental principle of Darwin's theory. Option E is incorrect because Option B is a false statement based on the theory.

Q33. All of the following are primary consumers except:

• A. Grasshopper
• B. Frog✓
• C. Sheep
• D. Cow
• E. Rabbit

Explanation: The correct answer is the frog, which is a secondary consumer. This is because frogs primarily eat insects that are themselves primary consumers, feeding on plants. In contrast, grasshoppers, sheep, cows, and rabbits are all herbivores that directly consume plants, making them primary consumers.

Q34. The seen zone below 2000 metres is called

• A. Euphotic zone
• B. Bathyal zone
• C. Abyssal zone✓
• D. Platonic zone
• E. None

Explanation: The correct answer is the abyssal zone, which is defined as the oceanic zone ranging from about 2,000 meters (6,600 feet) to 6,000 meters (20,000 feet) deep. This zone is characterized by complete darkness, cold temperatures, and high pressure. The euphotic zone is much shallower, only extending to about 200 meters, where sunlight supports photosynthesis. The bathyal zone lies between the euphotic and abyssal zones, from 200 meters to 2,000 meters deep, with limited light penetration. The 'Platonic zone' does not exist in oceanographic terms, making it an incorrect option. The option 'None' is incorrect because the abyssal zone accurately describes the conditions stated in the question.

Q35. Mushrooms belong to:

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

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

Q36. The botanical name of touch me not is

• A. Acacia nilotica
• B. Mimosa pudica✓
• C. Acacia catechu
• D. Prosopis glandulosa
• E. Albizia lebbeck

Explanation: The correct answer is Mimosa pudica. Mimosa pudica is widely known as the 'touch me not' plant due to its unique characteristic of closing its leaves when touched. This reaction is a defense mechanism to protect against herbivores. The other options refer to different plant species: Acacia nilotica (gum arabic tree), Acacia catechu (catechu tree), Prosopis glandulosa (honey mesquite), and Albizia lebbeck (siris tree), none of which have the same sensitive leaf response as Mimosa pudica.

Q37. Bat is

• A. A bird
• B. An insect
• C. A mammal✓
• D. A reptile
• E. An amphibian

Explanation: Bats are classified as mammals because they have fur, are warm-blooded, and give birth to live young. They are unique among mammals as they are capable of sustained flight, thanks to their wing structure. The other options are incorrect as birds, insects, reptiles, and amphibians possess different characteristics and classifications that do not align with those of bats. Birds have feathers and lay eggs; insects are invertebrates; reptiles have scales and are cold-blooded; amphibians have a distinct life cycle involving water and land phases.

Q38. Annelida is

• A. Acoelomate
• B. Pseudocoelomate
• C. Hemocoelomate
• D. Coelomate✓
• E. None of the above

Explanation: Annelids are coelomate animals, meaning they have a true coelom, which is a fluid-filled body cavity completely lined by mesodermal tissue. This coelom allows for the development and suspension of internal organs, providing structural support and aiding in the distribution of nutrients and waste.Option A, 'Acoelomate,' is incorrect because acoelomates lack a body cavity entirely. Option B, 'Pseudocoelomate,' is incorrect because pseudocoelomates have a body cavity that is only partially lined with mesoderm. Option C, 'Hemocoelomate,' is incorrect as this term is used to describe organisms with a hemocoel, which is not applicable to annelids. Option E, 'None of the above,' is incorrect because option D 'Coelomate' is the correct classification for annelids.

Q39. Which of the following processes have a net reaction of Pyruvic acid + 3 water molecules + 5 carrier electron ->3 CO2 + 5 carrier electron

• A. Glycolysis
• B. Fermentation
• C. Tricarboxylic acid cycle✓
• D. ETC
• E. None

Explanation: The correct answer is the Tricarboxylic acid cycle, also known as the Krebs cycle. This cycle involves the oxidation of pyruvic acid into carbon dioxide while transferring electrons to electron carriers like NAD+ and FAD. Glycolysis and fermentation are processes that occur before the TCA cycle and do not result in the complete oxidation of pyruvic acid to carbon dioxide. The Electron Transport Chain (ETC) is responsible for using electrons from carriers like NADH and FADH2 to produce ATP, not the direct conversion of pyruvic acid to carbon dioxide.

Q40. The source of oxygen in photosynthesis is

• A. CO2
• B. Glucose
• C. ATP
• D. H2O✓
• E. NADP

Explanation: During photosynthesis, water (H2O) is used in the light-dependent reactions where it is split into oxygen, protons, and electrons. The oxygen atoms from water are released as molecular oxygen (O2) into the atmosphere. This was confirmed by tracing oxygen atoms using the heavy isotope 18O, demonstrating that the oxygen released comes from water. Other molecules like CO2, glucose, ATP, and NADP are involved in photosynthesis but do not serve as the source of the oxygen released.

Q41. Ideal Gas Equation is obtained by combining:

• A. Boyle’s Law, Dalton’s Law and Charles's Law
• B. Boyle’s Law, Charle’s Law and Avogadro’s Law✓
• C. Dalton’s Law, Charle’s Law and Avogadro’s Law
• D. Boyle’s Law, Dalton’s Law and Avogadro’s Law
• E. All of the above

Explanation: The Ideal Gas Law is a fundamental equation in chemistry and physics that describes the behavior of an ideal gas. It is derived by combining three essential gas laws: Boyle's Law (which states that the pressure of a gas is inversely proportional to its volume), Charles's Law (which states that the volume of a gas is directly proportional to its temperature), and Avogadro’s Law (which states that the volume of a gas is directly proportional to the number of moles of gas). These relationships are mathematically expressed as PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature in Kelvin. Options including Dalton’s Law are incorrect because Dalton’s Law pertains to the partial pressures of gases in a mixture and does not directly contribute to the derivation of the Ideal Gas Equation.

Q42. Which light colour has the longest wavelength?

• A. Violet
• B. Blue
• C. Red✓
• D. Green
• E. Yellow

Explanation: The correct answer is Red. In the visible spectrum of light, red light has the longest wavelength, approximately 620 to 750 nanometers. Violet light, on the other hand, has the shortest wavelength, ranging from about 380 to 450 nanometers. Blue, green, and yellow light fall in between these two extremes, with blue having a shorter wavelength and yellow a longer wavelength compared to green.

Q43. The shape of the orbital is indicated by the symbol “ℓ” called:

• A. Principle Quantum number
• B. Magnetic Quantum number
• C. Azimuthal Quantum number✓
• D. Spin Quantum number
• E. None

Explanation: The correct answer is the azimuthal quantum number, denoted by the symbol 'ℓ'. This quantum number describes the shape of the orbital and is also known as the orbital angular momentum quantum number. It is distinct from other quantum numbers: the principal quantum number (n) indicates the size and energy of the orbital, the magnetic quantum number (m) describes the orientation of the orbital in space, and the spin quantum number (s) defines the spin orientation of the electron. Therefore, options A, B, D, and E are incorrect as they do not correspond to the quantum number that defines orbital shape.

Q44. Which of the following has same empirical and molecular formulas

• A. CH4
• B. H2O
• C. NaCl
• D. MgO
• E. All of these✓

Explanation: The smallest whole number ratio of atoms is present which represents the empirical formula. The molecular formula is also the same. In all other cases there is a whole number ratio of atoms which makes its empirical formula different from molecular formula.

Q45. In the Boyle’s Law, if the pressure of a gas is plotted versus the reciprocal of the volume, the curve obtained is:

• A. Parabolic curve
• B. Hyperbolic curve
• C. Straight line✓
• D. Symbolic
• E. All of these options

Explanation: When pressure is plotted against the reciprocal of the volume in Boyle's Law, a straight line is obtained. This straight line represents the inverse relationship between pressure and volume, where the gradient is the constant in Boyle's Law. On the other hand, plotting pressure against volume results in a hyperbolic curve, not a straight line.

Q46. Bioindicators are complex molecules that themselves are:

• A. Strong acids
• B. Strong bases
• C. Weak acids
• D. Weak bases
• E. Both weak acids and weak bases✓

Explanation: Bioindicators are complex molecules that can act as either weak acids (e.g. phenolphthalein) or weak bases (e.g. methyl orange). Strong acids and bases do not fall into the category of bioindicators, making options A and B incorrect. While weak acids (option C) and weak bases (option D) are possible bioindicators, the correct answer, option E, encompasses both weak acids and weak bases.

Q47. For a chemical reactionA → BThe threshold energy of reaction is 50 K.J/mol. The average internal energy of A is 25 K.J/mol. The activation energy of A is:

• A. 25 K.J/mol✓
• B. 50 K.J/mol
• C. 100 K.J/mol
• D. 125 K.J/mol
• E. 0 K.J/mol

Explanation: The activation energy for a chemical reaction is the minimum energy required to convert the reactants into products. It is calculated by subtracting the average internal energy of the reactants from the threshold energy. In this case, Activation energy = Threshold energy - Internal energy = 50 K.J/mol - 25 K.J/mol = 25 K.J/mol. This means option A is correct. Options B, C, and D are incorrect as they do not accurately reflect the relationship between threshold and internal energies. Option E is incorrect because it suggests no energy barrier, which is not the case here.

Q48. In a reaction:2H2O2(aq) + MnO2 → 2H2O(l) + O2(g)MnO2is a:

• A. Positive catalyst✓
• B. Negative catalyst
• C. Auto catalyst
• D. Bio catalyst
• E. None of these options

Explanation: Manganese dioxide (MnO2) is a positive catalyst in this reaction because it accelerates the decomposition of hydrogen peroxide into water and oxygen gas. It is not consumed in the process and does not appear as a product in the chemical equation.Negative catalysts slow down reactions, which MnO2 does not do here. An auto catalyst would be a product of the reaction that also acts as a catalyst, which is not the case for MnO2. Bio catalysts are enzymes, which are organic in nature, unlike the inorganic MnO2. Therefore, the correct classification for MnO2 in this context is a positive catalyst.

Q49. When the product of the ionic concentrations is equal to the solubility product, the solution is said to exist in:

• A. Unsaturated form
• B. Saturated form✓
• C. Super saturated form
• D. Both unsaturated form and saturated form
• E. None

Explanation: The correct answer is the saturated form. A solution is considered saturated when the product of the ionic concentrations equals the solubility product (Ksp). At this point, the solution cannot dissolve any more solute, and any additional solute will result in precipitation. This is not the case for an unsaturated solution, where the ionic product is less than the solubility product, allowing more solute to dissolve. A supersaturated solution occurs when the ionic product exceeds the solubility product, usually leading to the formation of a precipitate if disturbed. The option of both unsaturated and saturated is logically inconsistent, and 'None' is incorrect because the condition described is precisely that of saturation.

Q50. The conductance of electric current through solutions:

• A. Increases with dilution
• B. Increases with increase in concentration✓
• C. Increases with the decrease of absolute velocities of ions in a solution
• D. Increases by decreasing the temperature by 1 Celsius
• E. Increases by large increase in pressure

Explanation: The correct answer is that conductance increases with an increase in concentration. This is because a higher concentration of ions provides more charge carriers, which enhances the solution's ability to conduct electricity. Option A is incorrect because dilution reduces ion concentration, thus reducing conductance. Option C is incorrect because a decrease in ion velocity reduces ion mobility, leading to lower conductance. Option D is incorrect because conductance generally increases with temperature, not decreases. Option E is incorrect because pressure changes have an insignificant effect on the conductance of ionic solutions under normal conditions.

Q51. Which of the following is the characteristic of alkali metals?

• A. Low melting point✓
• B. High ionization energy
• C. High electronegativity
• D. Low boiling point
• E. None of the above

Explanation: Alkali metals, which are found in Group 1 of the periodic table, are characterized by their low melting points due to their atomic structure. They have a single electron in their outermost shell, which results in low ionization energy and low electronegativity. This makes them highly reactive and easily able to lose their valence electron. Options B and C are incorrect because alkali metals have low ionization energy and low electronegativity, not high. Option D is misleading because, although alkali metals have low melting points, their boiling points compared to non-metals are not necessarily low. Option E is incorrect because option A correctly describes a characteristic of alkali metals.

Q52. The formula of soda ash is

• A. Na2CO3H2O
• B. NaOH
• C. Na2CO3✓
• D. NaHCO3
• E. HCl

Explanation: Soda ash is commonly known as sodium carbonate, with the chemical formula Na2CO3. It is used in various industrial processes and products. The other options provided in the question are incorrect because they represent different compounds like sodium hydroxide, sodium bicarbonate, and hydrochloric acid, which are not equivalent to soda ash.

Q53. In the purification of bauxite, the method used for the purification of bauxite containing excess of silica is

• A. Hall's method
• B. Baeyer's method
• C. Serpeks method✓
• D. Electrolysis of pure alumina
• E. Hoopes electrolysis method

Explanation: Serpeck’s method is the correct choice as it is tailored for purifying bauxite ore containing excess silica. The process involves heating the powdered bauxite with carbon and passing a current of nitrogen to obtain aluminum nitride. The other options are incorrect as they are not specifically designed to address bauxite with high silica content.

Q54. The composition of turner's yellow pigment is

• A. Pb3(OH)2CO2
• B. Pb3O4
• C. PbCrO4
• D. PbCrO4 + PbO
• E. PbCl2·4PbO✓

Explanation: Turner's yellow, also known as patent yellow or lead oxychloride, has the chemical composition of PbCl2·4PbO. This compound is recognized for its strong yellow hue and has been historically used as a pigment in art. Other options provided represent different lead or chromium-based compounds, such as chrome yellow (PbCrO4), red lead (Pb3O4), or hypothetical formulations that do not correspond to Turner's yellow.

Q55. According to _ the elements are arranged in the ascending order of their atomic weights

• A. Dobereiner's triads
• B. Lothar Meyer's classification
• C. Newland's law of octaves✓
• D. Modern periodic law
• E. None of these

Explanation: Newland's law of octaves was an early attempt to classify elements based on the concept of periodicity. He arranged elements in increasing order of atomic masses and observed that every eighth element shared similar properties, akin to musical octaves. While it had limitations, this was a significant step toward the development of the periodic table. Dobereiner's triads grouped elements into sets of three based on similarities, but not by strict atomic weight order. Lothar Meyer's work focused on periodic trends but not specifically on atomic weights. The modern periodic law, developed later, organizes elements by atomic number rather than atomic weight.

Q56. Methane when heated in the absence of oxygen gives a by product " Carbon black" which is used in

• A. Rubber industry
• B. Pigments of paints
• C. Typewriter carbon paper
• D. Pigment of plastic
• E. All of the above✓

Explanation: Carbon black is a common black pigment that is produced by the incomplete combustion of hydrocarbons, such as methane. It is widely used across various industries due to its coloring and reinforcing properties. In the rubber industry, it is used to strengthen and color rubber products like tires. In the paint industry, it serves as a pigment for its deep black color. It is also used in making carbon papers and inks for writing and printing. Additionally, carbon black is used in plastics to provide pigmentation and improve UV resistance. Therefore, the correct answer is 'all of the above' as carbon black finds applications in all the mentioned areas.

Q57. Which of the following contain single bond

• A. Benzene
• B. Alkene
• C. Alkyne
• D. Alkane✓
• E. None of the above

Explanation: The correct answer is Alkane. Alkanes are composed entirely of single bonds between carbon atoms, making them saturated hydrocarbons. In contrast, Alkenes contain at least one double bond, Alkynes contain at least one triple bond, and Benzene is an aromatic compound with alternating single and double bonds. Therefore, only alkanes fit the description of containing solely single bonds.

Q58. 2 chloro 2 methyl propane is an example of

• A. Primary alkyl halide
• B. Secondary alkyl halide
• C. Tertiary alkyl halide✓
• D. Primary alcohol
• E. Secondary alcohol

Explanation: The correct answer is that 2-chloro-2-methylpropane is a tertiary alkyl halide. This is because the carbon atom bonded to the chloro group is also bonded to three other carbon atoms, which makes it a tertiary carbon. Primary alkyl halides have the halogen attached to a carbon bonded to only one other carbon, and secondary alkyl halides have it attached to a carbon bonded to two other carbons. Options D and E are incorrect because they refer to alcohols, which are characterized by the presence of a hydroxyl group (-OH), not a chloro group.

Q59. Potassium dichlorate is moderately soluble in water and gives

• A. Blue color in solution
• B. orange color in solution✓
• C. yellow color in solution
• D. purple color in solution
• E. black color in solution

Explanation: Potassium dichromate (K2Cr2O7) is a chemical compound that is well known for its bright orange color. This color is due to the presence of dichromate ions (Cr2O72−) in the solution. When dissolved in water, it imparts an orange hue to the solution. Other colors such as blue, yellow, purple, and black do not correspond to the appearance of potassium dichromate in solution. Blue is typically related to copper compounds, yellow to some chromates but not dichromates, purple to permanganates, and black is not characteristic of potassium dichromate.

Q60. CH3-C-CH3-CH3-CH3 is an example of

• A. Position isomerism
• B. Skeletal isomerism✓
• C. Functional group isomerism
• D. Metamerism
• E. None of the above

Explanation: The correct answer is skeletal isomerism, also known as chain isomerism. This type of isomerism occurs when compounds with the same molecular formula have different arrangements of their carbon backbone. In the case of CH3-C-CH3-CH3-CH3, also known as neo-pentane, the molecule can be rearranged to form other isomers like iso-pentane and n-pentane, which have different carbon skeletons.Position isomerism is incorrect because no functional groups or substituents change positions on the carbon chain. Functional group isomerism is not applicable as there is no change in functional groups. Metamerism is incorrect because it involves different alkyl groups attached to a heteroatom, which is not present in the molecule. None of the above is incorrect because skeletal isomerism accurately describes the situation.

Q61. When sodium acetate is heated with soda lime a hydrocarbon is obtained what is it

• A. Methane✓
• B. Ethane
• C. Ethyne
• D. Ethene
• E. Benzene

Explanation: When sodium acetate is heated with soda lime, a decarboxylation reaction occurs, leading to the formation of methane and sodium carbonate. The carboxyl group (COO-) in sodium acetate is removed as carbon dioxide, and the remaining methyl group (CH3-) forms methane (CH4). This is represented by the equation: CH3COONa + NaOH → CH4 + Na2CO3.The other options are incorrect because they do not result from the decarboxylation of sodium acetate. Ethane, ethyne, and ethene are hydrocarbons formed under different conditions and reactions. Benzene is a complex aromatic compound not related to this simple decarboxylation reaction.

Q62. In the first step of SN1 reaction _ molecule is/are involved so it is called

• A. one... unimolecular✓
• B. two... bimolecular
• C. three... trimolecular
• D. four... tetramolecular
• E. many... multimolecular

Explanation: In an SN1 reaction, the first step involves the ionization of the substrate to form a carbocation intermediate. This step is unimolecular because only the molecularity of one molecule (the substrate) changes. This unimolecular nature is why it is called SN1, where 'S' stands for substitution, 'N' for nucleophilic, and '1' for unimolecular. The other options are incorrect as they describe scenarios involving more than one molecule, which are not characteristic of the SN1 mechanism.

Q63. Which of the following is the composition of methylated spirit

• A. Ethanol 60, Water 20, Methanol 20.
• B. Ethanol 75, Water 10, Methanol 15.
• C. Ethanol 85, Water 11, Methanol 4✓
• D. Ethanol 90, Water 5, Methanol 5
• E. Ethanol 95, Water 4, Methanol 1

Explanation: The correct composition of methylated spirit is 85% ethanol, 11% water, and 4% methanol. This combination ensures that the spirit is effective for its intended uses, such as cleaning and fuel, while the methanol renders it undrinkable. Other options either have too much methanol, making them highly toxic, or too much ethanol, deviating from the standard formulation.

Q64. Which of the following is not the use of acetone

• A. It is used as a nail polish remover
• B. It is used in the silvering of mirror✓
• C. It is used in the formation of chloroform
• D. It is used in the preparation of artificial serum
• E. It is used in the preparation of synthetic rubber

Explanation: The correct answer is Option B: Acetone is not used in the silvering of mirrors. Silvering of mirrors typically involves chemicals like formaldehyde and silver nitrate. Acetone, on the other hand, is commonly used as a solvent, especially in removing nail polish, in chemical synthesis reactions such as forming chloroform, in preparing synthetic rubber, and in various laboratory applications such as preparing artificial serum. Therefore, all the other options are legitimate uses of acetone, whereas silvering of mirrors is not.

Q65. Which of the following is the planar trigonal molecule

• A. HCl
• B. BeCl2
• C. BF3✓
• D. CO2
• E. CS2

Explanation: BF3 is a trigonal planar molecule because it consists of a central boron atom bonded to three fluorine atoms, with no lone pairs on the boron. This results in a 120-degree bond angle between the fluorine atoms, leading to a planar molecular shape. In contrast, HCl is a linear diatomic molecule, BeCl2 is linear due to its sp hybridization, and both CO2 and CS2 are linear due to their central atoms being bonded to two other atoms with no lone pairs.

Q66. Covalent compounds

• A. crystals are made up of ions
• B. are non-electrolytes✓
• C. are insoluble in organic solvents
• D. are soluble in water
• E. are electrolytes

Explanation: Covalent compounds are characterized by the sharing of electrons between atoms, forming molecules rather than ions. As a result, they do not conduct electricity and are classified as non-electrolytes. They are typically soluble in organic solvents due to similar polarities but are generally insoluble in water. The other options are incorrect because they describe properties that are not characteristic of covalent compounds, such as forming ions or being electrolytes.

Q67. The rate at which a substance reacts is proportional to its active mass and the rate of chemical reaction is proportional to the product of active masses o reactants

• A. Boyle's Law
• B. Law of Mass Action✓
• C. Charles's Law
• D. Avogadro's Law
• E. Dalton's Law

Explanation: The correct answer is the Law of Mass Action, which states that the rate of a chemical reaction is proportional to the product of the active masses, or concentrations, of the reactants. This principle is foundational in chemical kinetics. Boyle's Law, Charles's Law, Avogadro's Law, and Dalton's Law all relate to the behavior of gases under various conditions and do not pertain to the rates of chemical reactions.

Q68. the sign of Delta H in exothermic reaction is:

• A. negative✓
• B. positive
• C. neither positive nor negative
• D. continuously changing
• E. none of the above

Explanation: An exothermic reaction is characterized by the release of heat energy, resulting in a negative change in enthalpy (ΔH). This is why the sign of ΔH in an exothermic reaction is negative. The other options are incorrect because they describe characteristics of endothermic reactions or do not align with the definition of exothermic reactions.

Q69. Change in the property of a system (in thermodynamics) is equal to

• A. The value of the property in the final state minus the value of the property in the initial state✓
• B. The value of the property in the initial state minus the value of the property in the final state
• C. The sum of the value of the property in the initial state and the value of the property in the final state
• D. The product of the value of the property in the final state and the value of the property in the initial state
• E. Does not depend on the initial and final state of properties

Explanation: The correct answer is that the change in a property is the value of the property in the final state minus the value in the initial state. This principle is fundamental in thermodynamics, where changes are often expressed as differences (e.g., ΔU = Uf - Ui for internal energy). The incorrect options either reverse this order, use addition or multiplication instead of subtraction, or incorrectly suggest that the change is independent of the initial and final values, all of which are misinterpretations of how properties change in a system.

Q70. The advantages of synthetic fibers are

• A. Lightness of weight
• B. Ease of ironing
• C. Softness
• D. Heat reaction
• E. All of the above✓

Explanation: Synthetic fibers are produced through chemical processes, allowing for control over their properties. They are typically lighter and more durable than natural fibers, often require less ironing due to their wrinkle resistance, and can be engineered for softness. However, their reaction to heat can be a limitation, as synthetic materials may melt or deform at high temperatures. Thus, options A, B, and C are advantages, while D is less of an advantage, making E the most comprehensive choice.

Q71. The radioactivity of a certain radioactive element drops to 1/64 of its initial value in 30 seconds. Its half-life is:

• A. 2 seconds
• B. 5 seconds✓
• C. 4 seconds
• D. 6 seconds

Explanation: The radioactivity of the element drops to 1/64 of its initial value, which means it undergoes 6 half-lives (since (1/2)6 = 1/64). Given that this decay to 1/64 occurs in 30 seconds, the half-life (T1/2) can be calculated as:T1/2 = Total time / Number of half-lives = 30 seconds / 6 = 5 seconds.

Q72. In full wave rectification, the output D.C. voltage across the load is obtained for

• A. The positive half cycle of input A.C.
• B. The complete cycle of input A.C.✓
• C. The negative half cycle of input A.C.
• D. All of the given options

Explanation: In full wave rectification, the entire cycle of the input A.C. is converted into D.C. voltage across the load. This process utilizes both the positive and negative half cycles of the input A.C., effectively doubling the frequency of the output D.C. compared to half wave rectification. Option B is correct because full wave rectification processes the complete cycle of A.C., producing a continuous D.C. output.

Q73. The north pole of a magnet is brought near a metallic ring. The direction of the induced current in the ring will be:

• A. Clockwise
• B. Anticlockwise✓
• C. Towards north
• D. Towards south

Explanation: When a north pole of a magnet is brought near a metallic ring, Lenz's law states that the induced current will flow in a direction that opposes the change in magnetic field. Therefore, the ring will act to repel the approaching north pole by inducing a current that makes the ring itself behave like a north pole. This results in an anticlockwise current flow in the ring, as determined by applying the right-hand rule. The other options either describe directions that are not applicable to current flow or suggest a behavior (such as attraction) that does not align with Lenz's law.

Q74. Three lamps of 100 W each are operated for 2 hours daily. The energy consumed in one month will be:

• A. 1 kWh
• B. 18 kWh✓
• C. 6 kWh
• D. 24 kWh

Explanation: Each lamp of 100W translates to 0.1 kW. For 2 hours, one lamp consumes 0.2 kWh (0.1 kW x 2 hours). Three lamps together consume 0.6 kWh daily (0.2 kWh x 3). Therefore, over one month (30 days), the total energy consumed is 18 kWh (0.6 kWh x 30 days).Option A (1 kWh) significantly underestimates the usage as it might consider only one lamp or fewer days. Option C (6 kWh) also underestimates by perhaps not accounting for all lamps or full month usage. Option D (24 kWh) overestimates, possibly by assuming longer usage duration or additional lamps.

Q75. A bullet of mass 50g is fired horizontally from a building 45m high. It reaches the ground after

• A. 1s
• B. 5s
• C. 3s✓
• D. 4s

Explanation: The problem is solved by focusing on the vertical motion of the bullet. We use the second equation of motion, S = ut + (½)at², where S is the distance (45m), u is the initial vertical velocity (0 m/s since the bullet is fired horizontally), a is the acceleration due to gravity (10 m/s²), and t is the time.Substituting these values, the equation becomes: 45 = 0(t) + (½)(10)(t²). Simplifying this gives: 45 = 5t². Solving for t² gives t² = 9, hence t = 3 seconds.Thus, the correct answer is 3 seconds. Options 1s, 5s, and 4s are incorrect because they do not satisfy the equation derived from the given conditions.

Q76. Read the statement given below

• A. Option A: Hooke's Law✓
• B. Option B: Newton's First Law
• C. Option C: Pascal's Principle
• D. Option D: Bernoulli's Equation
• E. Option E: Archimedes' Principle

Explanation: The correct answer is Hooke's Law, which states that the force (F) applied to a spring is directly proportional to the displacement (x) of the spring, as long as the material remains within its elastic limit. This is expressed mathematically as F = kx, where k is the spring constant. This relationship is central to understanding material elasticity.Other options describe different principles: Newton's First Law pertains to motion, Pascal's Principle to fluid pressure, Bernoulli's Equation to fluid flow, and Archimedes' Principle to buoyancy. None of these relate directly to the force-displacement relationship in solids as Hooke's Law does.

Q77. Light can be polarised by all of the following methods, except:

• A. Selective absorption
• B. Double refraction
• C. Scattering of light
• D. Diffraction✓
• E. Reflection

Explanation: Diffraction does not polarize light because it involves the bending and spreading of waves around obstacles, which doesn't lead to the alignment of light waves in a specific direction. Other methods like selective absorption, double refraction, scattering, and reflection can polarize light by aligning the light waves in particular orientations. This is why diffraction is the correct answer as the method that does not cause polarization.

Q78. A chess piece 4 cm high is located 10 cm from the converging lens whose focal length is 20 cm. The image will be formed at a distance of:

• A. +8 cm
• B. +10 cm
• C. +20 cm
• D. -20 cm✓
• E. -15 cm

Explanation: To find the image distance (v), use the lens formula: \( \frac{1}{f} = \frac{1}{v} + \frac{1}{u} \) where \( f = 20 \text{ cm} \) (focal length) and \( u = -10 \text{ cm} \) (object distance, negative as per sign convention for lenses). Rearranging gives \( \frac{1}{v} = \frac{1}{f} - \frac{1}{u} = \frac{1}{20} - \frac{1}{(-10)} \). Solving this, \( v = -20 \text{ cm} \). The negative sign indicates a virtual image on the same side as the object. Other options result from incorrect application of the lens formula.

Q79. When the direction of the force and displacement are opposite, work done is:

• A. Negative✓
• B. Positive
• C. Zero
• D. None of these

Explanation: According to the formula,W = FdcosθIf both force and displacement are opposite in direction, then θ = 180oW = Fd cos180oWe know cos 180o = -1W = Fd (-1)W = -FdHence, the work done will be negative. So, option A is the correct option.

Q80. A neutron of mass 1.7 x 10-27 kg travels a distance of 12m in a time interval of 3.6 x 10-4. Assuming its speed was constant, its kinetic energy is:

• A. 9.256 x 10-19 Joule✓
• B. 8.005 x 10-19 Joule
• C. 0.001 x 10-29 Joule
• D. 0.256 x 10-4 Joule
• E. 7.256 x 10-20 Joule

Explanation: To solve the problem, first calculate the speed of the neutron using the formula speed = distance / time. Here, the distance is 12 m and the time is 3.6 x 10-4 s, resulting in a speed of 3.3 x 104 m/s. Next, calculate the kinetic energy using KE = 1/2mv², where m is the mass of the neutron (1.7 x 10-27 kg) and v is the speed (3.3 x 104 m/s). The correct kinetic energy is 9.256 x 10-19 Joule. Other options are incorrect due to miscalculations, such as errors in the exponent or arithmetic mistakes.

Q81. The electric force between two static point charges varies directly to the product of charges and inversely with the square of the distance between them is:

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

Explanation: Coulomb's Law is the correct answer because it specifically addresses the force between two point charges, stating that this force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. This is a fundamental principle in electrostatics. The other laws mentioned pertain to different phenomena: Ohm’s Law to electrical circuits, Lenz’s Law to electromagnetic induction, Ampere’s Law to the relationship between electricity and magnetism, and Faraday’s Law to electromagnetic induction.

Q82. The electric flux is maximum when the angle “θ” between electric intensity and vector area is:

• A. θ = 90˚
• B. θ ≤ 90˚
• C. θ = 0˚✓
• D. θ ≥ 90˚
• E. θ = 180˚

Explanation: The electric flux, represented by Φ, is given by the equation Φ = EA cos(θ), where E is the electric field strength, A is the area through which the field lines pass, and θ is the angle between the electric field lines and the normal (perpendicular) to the surface. When θ = 0˚, cos(θ) = 1, making the electric flux maximum, Φ = EA. For θ = 90˚, cos(θ) = 0, resulting in zero electric flux. At θ = 180˚, cos(θ) = -1, leading to negative flux, indicating direction reversal. Therefore, only θ = 0˚ gives the maximum positive flux.

Q83. According to Ohm’s Law the relationship that exists between current and potential difference is:

• A. Parabolic
• B. Hyperbolic
• C. Linear✓
• D. Symbolic
• E. None of these

Explanation: According to Ohm's Law, the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points, provided the temperature remains constant. This relationship is mathematically expressed as V = IR, where R is the resistance. This indicates a linear relationship because as voltage increases, current also increases proportionally if resistance is constant. The other options (Parabolic, Hyperbolic, Symbolic) do not accurately represent this direct proportionality.

Q84. At a constant pressure the volume “V” of a given mass of a gas is directly proportional to its absolute temperature “T”, is stated by:

• A. Boyle’s Law
• B. Charles's Law✓
• C. Dalton’s Law
• D. General Gas Law
• E. None of these options

Explanation: Charles's Law is the correct answer as it states that the volume of a gas is directly proportional to its absolute temperature when pressure is held constant. Mathematically, this can be expressed as V = kT, where V is the volume, T is the temperature, and k is a constant.Boyle’s Law relates pressure and volume, but not temperature. Dalton’s Law deals with partial pressures in gas mixtures, not volume or temperature. The General Gas Law is an all-encompassing law but does not specifically highlight the direct relationship between volume and temperature at constant pressure as Charles's Law does.

Q85. Which of the following statement/s regarding the Second Law of Thermodynamics is/are correct?

• A. It is impossible to derive a continuous supply of work by cooling a body to a temperature lower than that of the coldest of its surroundings.✓
• B. It is possible to derive a continuous supply of work by cooling a body to a temperature lower than that of the coldest of its surroundings.
• C. It is impossible to derive a continuous supply of work by heating a body to a temperature more than that of the hottest of its surroundings.
• D. Both It is possible to derive a continuous supply of work by cooling a body to a temperature lower than that of the coldest of its surroundings & It is impossible to derive a continuous supply of work by heating a body to a temperature more than that of the hottest of its surroundings.
• E. None of these

Explanation: The correct answer is option A. According to the Second Law of Thermodynamics, specifically Kelvin's statement, it is impossible to derive a continuous supply of work by cooling a body to a temperature lower than that of the coldest of its surroundings. This is because absolute zero, the theoretical lowest temperature, is unattainable in practice. Options B and D are incorrect because they contradict this principle. Option C incorrectly shifts the focus to heating rather than cooling and does not align with standard thermodynamic principles. Option E is incorrect as it disregards the correct statement provided in option A.

Q86. circuit in which there is a current of 15 amperes is changed so that the current falls to zero in 0.5 seconds. If an average e.m.f of 300 volts is induced. What is the self inductance of the circuit?

• A. 4 henrys
• B. 6 henrys
• C. 8 henrys
• D. 10 henrys✓
• E. 2 henrys

Explanation: The correct answer is 10 henrys. The self-inductance (L) is calculated using the formula L = e.m.f / (dI/dt), where e.m.f is the electromotive force and dI/dt is the rate of change of current. Here, the change in current (dI) is 15 amperes and the time (dt) is 0.5 seconds, giving a rate of change of 15/0.5 = 30 A/s. With an average e.m.f of 300 volts, L = 300 / 30 = 10 henrys.Other options underestimate the self-inductance because they do not correctly apply the formula for self-inductance given the rate of change of current and the induced e.m.f.

Q87. Potentiometer is a device used for measuring the _ between the two points of a circuit:

• A. flux density
• B. resistance
• C. current
• D. voltage✓
• E. none of these

Explanation: A potentiometer is a device used to measure the potential difference, or voltage, between two points in a circuit. The potential difference is synonymous with voltage, and therefore, the correct option is 'voltage.' Other options like flux density, resistance, and current are measured with different instruments such as magnetometers, ohmmeters, and ammeters, respectively.

Q88. A galvanometer has a resistance of 50 Ohms and gives full scale deflection when a current of 0.005 amperes flows in it. Find the value of the shunt resistance to convert it into an ammeter of range 20 amperes.

• A. 0.316 ohms
• B. 0.0125 ohms✓
• C. 0.007 ohms
• D. 2.9 ohms
• E. 1.5 ohms

Explanation: To convert a galvanometer into an ammeter, a shunt resistance is added in parallel. The formula for shunt resistance (Rs) is given by Rs = IgRg / (I-Ig), where Ig is the current for full-scale deflection of the galvanometer, Rg is the resistance of the galvanometer, and I is the total current range of the ammeter. Substituting the given values: Rs = (0.005 x 50)/(20-0.005) = 0.0125 ohms, which is Option B.Other options result from errors such as incorrect formula application, arithmetic mistakes, or misunderstanding the problem's requirements.

Q89. A battery of 10 volts is connected to two resistors of 3 ohms and 2 ohms joined together in series. The current through the circuit will be:

• A. 1.2 Amperes
• B. 1.0 A
• C. 2.0 A✓
• D. 3.0 A
• E. 5.0 A

Explanation: To find the current through the circuit, first calculate the total resistance of the resistors in series: R = 3 ohms + 2 ohms = 5 ohms. Then, apply Ohm's Law, I = V/R, where V is the voltage (10 volts) and R is the total resistance (5 ohms). This gives I = 10/5 = 2 A. Therefore, the correct answer is 2.0 A.Other options are incorrect due to errors in either the resistance calculation or the application of Ohm's Law.

Q90. A magnetic field is a region in which a force is experienced on a moving charge or a magnet. This force depends upon:I. The magnitude of charge qII. The speed of the moving charge vIII. The magnetic field of induction B

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

Explanation: We know that the force acting on the charge is F = qvBAccording to the formula, it depends on the charge q, its velocity v and the magnetic field in the region B. Hence, option E is correct.

Q91. Three dimensional images of projects obtained by using lasers is a process called:

• A. Plating
• B. Photography
• C. Welding
• D. Holography✓
• E. None of these

Explanation: Holography is the correct answer because it is a technique that uses lasers to create three-dimensional images known as holograms. While photography captures flat, two-dimensional images, holography records the light field, allowing the viewer to see different perspectives as if the object were real. Plating and welding are industrial processes unrelated to image creation. 'None of these' is incorrect because holography is a valid process for creating 3D images.

Q92. Which of the following statements is correct?

• A. RNA is the primary genetic material in bacteria
• B. RNA is the genetic material for all viruses
• C. DNA is the genetic material for the majority of living organisms
• D. Some viruses use RNA as their genetic material✓

Explanation: Some viruses use RNA as their genetic material. Viruses can contain either DNA or RNA, depending on the type. Examples of RNA viruses include the influenza virus, HIV, and SARS-CoV-2.Option A: Bacteria use RNA as their genetic material. This is incorrect because bacteria always use DNA, not RNA, as their hereditary material.Option B: All viruses use RNA as their genetic material. This is incorrect because many viruses, such as herpesvirus or adenovirus, have DNA genomes instead.Option C: DNA is the genetic material for most living organisms. While true in general, this statement does not specifically address viruses, so it does not answer the question in context.

Q93. The audible frequency range for a normal human ear is:

• A. 20 Hz to 20,000 Hz✓
• B. 20 Hz to 200,000 Hz
• C. 200 Hz to 20,000 Hz
• D. 20 Hz to 80 Hz
• E. 20 Hz to 200 Hz

Explanation: The audible frequency range for a normal human ear is from 20 Hz to 20,000 Hz, which encompasses the range of sound frequencies that humans can detect. Options B, C, D, and E all either have incorrect lower or upper limits that fall outside the true range of human hearing. Humans typically cannot hear frequencies above 20,000 Hz, and can hear frequencies as low as 20 Hz. This range covers everything from the low rumble of a bass to the high-pitched chirp of a bird.

Q94. The length of a measuring rod is 1m when it is at rest. What will be its length if it is moving with a velocity one third of the speed of light?

• A. 2√2 / 3 meters✓
• B. 1 meter
• C. 3/4 meter
• D. 0.5 meter
• E. 2/3 meter

Explanation: The length contraction formula, L = Lo√(1-(v²/c²)), is used to calculate the length of an object in motion. Here, Lo = 1 meter, v = c/3, and c is the speed of light. Substituting these values, we get L = 1√(1-(1/9)) = √(8/9) = 2√2 / 3 meters. This shows that the length of the measuring rod contracts to 2√2 / 3 meters when moving at one third the speed of light. The other options are incorrect as they either do not apply the formula correctly or do not account for length contraction at relativistic speeds.

Q95. The horizontal distance from the origin (x=0, y=0) to the point where the projectile returns (X=R, Y=0) is called

• A. Angle of the projectile
• B. Height of the projectile
• C. Range of the projectile✓
• D. Direction of the projectile
• E. None of these

Explanation: The horizontal distance traveled by a projectile is known as its 'range.' This is the distance from the point of launch (origin) to the point where it lands back at the same vertical level. The other options refer to different aspects of projectile motion. The angle of the projectile determines its trajectory, the height refers to the peak point in its path, and the direction indicates its path or line of motion. 'None of these' is incorrect because 'range' is the precise term for the horizontal distance.

Q96. The Right-Hand-Rule is applied to find:

• A. The direction of a vector obtained by the vector product of two vectors✓
• B. The magnitude of a vector obtained by the vector product of two vectors
• C. Neither the direction nor the magnitude
• D. Both the direction of a vector obtained by the vector product of two vectors & the magnitude of a vector obtained by the vector product of two vectors
• E. None of these

Explanation: The Right-Hand Rule is a mnemonic for understanding direction in the context of vector cross products in physics and mathematics. To apply it, position your right hand so that your thumb points in the direction of the first vector (v1), and your fingers curl towards the second vector (v2). Your thumb will point in the direction of the resultant vector (v1 x v2). This rule does not provide information regarding the magnitude of the vector, which is calculated using a separate formula involving the sine of the angle between the vectors.

Q97. The centre of mass of a system of particles:

• A. Coincides always with the centre of gravity
• B. Never coincides with the centre of gravity
• C. Coincides always with the centre of gravity only in a uniform gravitational field✓
• D. Coincides always with the centre of gravity only in a changing gravitational field.
• E. none of these

Explanation: The centre of mass of a system of particles coincides with the centre of gravity when the gravitational field is uniform across the entire system. In such fields, the gravitational force acts uniformly on all parts of the system, making the centre of gravity coincide with the centre of mass. In non-uniform gravitational fields, the centre of gravity may vary in position relative to the centre of mass due to differences in gravitational force across the system.

Q98. If we go away from the surface of the earth a distance equal to the radius of the earth, the value of ‘g’ will become:

• A. one fourth✓
• B. one eighth
• C. one ninth
• D. One sixteenth
• E. fourteen times

Explanation: The gravitational force (g) is given by the formula g = GM/R². If we move a distance equal to the Earth's radius (R) away from the surface, the distance from the center of the Earth becomes 2R. According to the inverse square law, the gravitational force is inversely proportional to the square of the distance from the center of the Earth. Thus, g' = GM/(2R)² = GM/4R² = 1/4 * (GM/R²). Therefore, the value of g becomes one fourth of its original value. Options B, C, D, and E are incorrect as they do not correctly apply the inverse square law to the change in distance.

Q99. Geiger counter is a portable device widely used for the detection of:

• A. charge
• B. Ionising particles✓
• C. velocity
• D. speed
• E. acceleration

Explanation: A Geiger counter is a portable device used for detecting and measuring ionising radiation, such as alpha and beta particles, and gamma rays. It is not designed to measure charge, velocity, speed, or acceleration. These other options are related to different physical concepts or quantities that require other types of instruments to measure.

Q100. machine needed 1000 J of energy to raise a 10 kg block at a distance of 6 m, what is the machine efficiency?

• A. 39%
• B. 59%✓
• C. 49%
• D. 100%
• E. none of these

Explanation: The machine's efficiency is determined by comparing the useful work output to the energy input. The energy input is given as 1000 J. The useful work output is calculated using the formula for gravitational potential energy, W = mgh, where m = 10 kg, g = 9.8 m/s2, and h = 6 m, resulting in 588 J. The efficiency is then calculated as (output/input) x 100% = (588 J / 1000 J) x 100% = 59%. Other options either misinterpret the energy values, assume perfect efficiency, or suggest values not supported by the calculations.