Sindh Mcat Nts 2009 — Solved Past Paper with Answers

Q1. Read the passage to answer the given question:It is of course a little absurd to speak of Asia as a unity, and only opposition to Western Imperialism which has caused people to think in these terms. Asia contains half the population of the world and at least three very distinct civilizations: that of Islam, that of India, and that of China. These differ from each other just as much as they differ from the civilization of Christened, there is not the faintest reason to expect them all to act in unison. What is to be hoped is, an endeavor after cultural or political unity, but a determination to uphold independence at home and to respect it elsewhere - and when I speak of independence, I am not only thinking of politics but also of culture. There is a great danger of too much cultural uniformity. No great civilization has ever been cosmopolitan.What can cultural uniformity not lead to?

• A. It will not lead to the formation of a great civilization✓
• B. It will lead to the formation of a great civilization
• C. It will lead to the formation of rich culture
• D. It will to the change of environment
• E. It will lead to the destruction of values

Explanation: “There is great danger of too much cultural uniformity. No great civilization has ever been cosmopolitan”As mentioned in the extraction from the passage above, cultural uniformity can not lead to the formation of a great civilization.

Q2. Read the passage to answer the given question:It is of course a little absurd to speak of Asia as a unity, and only opposition to Western Imperialism which has caused people to think in these terms. Asia contains half the population of the world and at least three very distinct civilizations: that of Islam, that of India, and that of China. These differ from each other just as much as they differ from the civilization of Christened, there is not the faintest reason to expect them all to act in unison. What is to be hoped is, an endeavor after cultural or political unity, but a determination to uphold independence at home and to respect it elsewhere - and when I speak of independence, I am not only thinking of politics but also of culture. There is a great danger of too much cultural uniformity. No great civilization has ever been cosmopolitan.What can cultural uniformity not lead to?

• A. It will not lead to the formation of a great civilization✓
• B. It will lead to the formation of a great civilization
• C. It will lead to the formation of rich culture
• D. It will to the change of environment
• E. It will lead to the destruction of values

Explanation: “There is great danger of too much cultural uniformity. No great civilization has ever been cosmopolitan”As mentioned in the extraction from the passage above, cultural uniformity can not lead to the formation of a great civilization.

Q3. Complete the sentences by choosing the most appropriate word, from the given lettered choices (A to E) below each:Nearly everyone dreams of building _ ideal house.

• A. Its
• B. Their✓
• C. His
• D. Him
• E. Them

Explanation: Option A: “Everyone” is not referred to as an objectOption B: 'Their' represents everyone.Option C: 'His' talks about one specific person.Option D: 'Him' shows belonging.Option E: 'Them' also shows belonging.

Q4. Complete the sentences by choosing the most appropriate word, from the given lettered choices (A to E) below each:Life _ water, light, a moderate temperature and a variety of chemical elements.

• A. Finds
• B. Reveals
• C. Designs
• D. Calculates
• E. Requires✓

Explanation: Option A: This option is incorrect. Option B: This option is incorrect. Option C: Life is not capable of designing. Option D: Life is not capable of calculating. Option E: For life, water, light, a moderate temperature and a variety of chemical elements are required.

Q5. Identify the word or phrase that needs to be changed for the sentence to be correct:The stories that she makes out for her children ought to be written down and published.

• A. That
• B. Makes out✓
• C. Ought to
• D. Written down
• E. No error

Explanation: "That" is correctly placed as a demonstrative pronoun.To "make out" means to manage with some difficulty to see or hear someone or something so it is incorrectly used here. "Makes" would be the correct word for the blank."Ought to" can be used to indicate light responsibility or urgency. It is correctly used in the sentence.It means to record something by writing down.An error was present in the sentence.

Q6. Choose the word most similar in meaning to the capitalised one.DISRUPTION

• A. Comfort
• B. Luxury
• C. Trouble✓
• D. Freedom
• E. Calm

Explanation: Problems which interrupt an event, activity, or process. Option A: Disruption is negative, comfort is positive. Option B: Luxury is comfort. Option C: Trouble and disruption are negative. Option D: Freedom is positive Option E: Calm positive and opposite to disruption.

Q7. Choose the word most similar in meaning to the capitalized one:INEVITABLE:

• A. Doubtful
• B. Deny
• C. Unexpected
• D. Certain✓
• E. Unusual

Explanation: Inevitable means something which is bound to happen or is very certain, undoubtful, and clear.

Q8. Choose the correct antonym of the given word:Eradication

• A. Suppression
• B. Termination
• C. Control
• D. Establish✓

Explanation: To establish something means to begin it or bring it about. It means the complete opposite of eradication.

Q9. Choose the correct antonym to the given word:Interruption

• A. Break
• B. Continuity✓
• C. Injury
• D. Difference

Explanation: The unbroken and consistent existence or operation of something over time is continuity. It is the opposite of interruption.

Q10. The muscles attached to the bones are

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

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

Q11. The law of Dominance is illustrated in green pea by:

• A. Homozygous Tall x Heterozygous Tall
• B. Heterozygous Tall x Heterozygous Tall
• C. Homozygous Tall x Homozygous Tall
• D. Pure short x Pure short
• E. Homozygous Tall x Pure short✓

Explanation: The law of dominance cross in green pea is performed between homozygous dominant and homozygous recessive.

Q12. In the Hardy-Weinberg principle, p2 + 2pq + q2 = 1, q2 is the frequency of the:

• A. Homozygous dominant
• B. Heterozygous dominant
• C. Heterozygous recessive
• D. Homozygous recessive✓
• E. Standard genes

Explanation: In the Hardy-Weinberg principle, p2 is homozygous dominant, 2pq is heterozygous and q2 is homozygous recessive.

Q13. Fungi do not contain:

• A. Cell wall
• B. Hyphae
• C. Chlorophyll✓
• D. Mycelium
• E. Spores

Explanation: Unlike plant cells, fungal cells do not have chloroplasts or chlorophyll. Many fungi display bright colours arising from other cellular pigments, ranging from red to green to black.

Q14. Identify the incorrect statement about Charles Darwin’s Theory:

• A. The individuals of species have variation among them
• B. There is always a tendency of overproduction in a species
• C. Vast gradual changes result in the origin of a new species
• D. Favourable variations survive and unfavourable will be terminated
• E. Intraspecific competition occurs between different species and interspecific competition occurs among the individuals in a species✓

Explanation: Theory in biology postulates that the various types of plants, animals, and other living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations.

Q15. Identify the incorrect statement from the following:

• A. Apical growth increases the length of stems and roots.
• B. Xylem is situated on the outer side of the cambium ring and phloem is situated on the inner side✓
• C. Secondary growth increases the diameter of stems and root.
• D. The cells in elongation phase don't divide.
• E. The cells in formative regions are closely packed together.

Explanation: A plant grows new tissue from an apical meristem in apical growth which increases the length of stems and roots

Q16. According to _, protein layers are not confined to the surface of the membrane but embedded in lipid layers.

• A. Lock and Key model
• B. Induced fit model
• C. Fluid Mosaic model✓
• D. Lotka Volterra model
• E. All of the above

Explanation: The fluid mosaic model describes the cell membrane as a tapestry of several types of molecules (phospholipids, cholesterols, and proteins) that are constantly moving.

Q17. In a typical nucleotide, the nitrogenous base is attached to _ carbon of pentose sugar.

• A. 5th
• B. 4th
• C. 3rd
• D. 1st✓

Explanation: A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.

Q18. Binomial nomenclature was first proposed by:

• A. Charles Darwin (1859)
• B. Rudolph Virchow (1855)
• C. Louis Pateur (1862)
• D. Carolus Linnaeus (1707)✓
• E. Robert Brown (1773)

Explanation: The system of nomenclature in which two terms are used to denote a species of a living organism, the first one indicating the genus and the second the specific epithet.

Q19. _ causes amoebic dysentery in humans:

• A. Pelomyxa palustris
• B. Entamoeba histolytica✓
• C. Trichonympha
• D. Trypanosoma
• E. Radiolarian ooze

Explanation: Amoebic dysentery is caused by the protozoan parasite Entamoeba histolytica. It is transmitted in areas where poor sanitation allows contamination of drinking water and food with feces. In these areas, up to 40% of people with diarrhea may have amoebic dysentery.

Q20. The main process that occurs in the dark reaction in photosynthesis is:

• A. That water is split
• B. Light energy is converted into chemical energy
• C. That glucose is oxidized
• D. That carbon-dioxide is fixed✓
• E. None of the above

Explanation: The main process that occurs in the dark reaction (also known as the Calvin Cycle) in photosynthesis is the synthesis of glucose. The dark reaction takes place in the stroma of chloroplasts and does not directly require light. It follows the light-dependent reactions (such as photosystem I and II) that capture and convert light energy into chemical energy in the form of ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate). In the Calvin Cycle, the primary goal is to use the ATP and NADPH produced during the light-dependent reactions to convert carbon dioxide (CO2) into glucose. The key steps of the Calvin Cycle include carbon fixation, reduction, and regeneration of the starting molecule (RuBP, ribulose-1,5-bisphosphate). The final product is glucose, which can be used by the plant for energy and other metabolic processes.

Q21. _ is commonly known as hook worm:

• A. Ancyclostoma duodenale✓
• B. Ascaris lumbericoides
• C. Enteroblus vermicularis
• D. Hirudinaria
• E. Wuchereria

Explanation: Ancylostoma duodenale is a species of the roundworm genus Ancylostoma. It is a parasitic nematode worm and commonly known as the Old World hookworm.

Q22. An organism appears to be a segmented worm. Upon observation, it is determined that the organism has a closed circulation, a mouth, and an anus and does not have an exoskeleton. The organism most likely belongs to the phylum:

• A. Mollusca
• B. Annelida✓
• C. Echinodermata
• D. Arthropoda
• E. Chordate

Explanation: Annelida: This phylum includes segmented animals like; earthworms, leech, etc Their body is soft and bilaterally symmetrical Their body is divided into the ring like grove(segments) called annuli. They have a complete digestive system from the mouth to anus Excretion is by nephridia. They have a closed circulatory system. Sexes may be separate or united (sexual reproduction ). The true body cavity is present. Eg; Pheretima, leech.

Q23. Ileum is about _ long.

• A. 3.6 millimeters
• B. 3.6 centimeters
• C. 3.6 inches
• D. 3.6 meters✓
• E. 3.6 kilometers

Explanation: The ileum is about 3.6 meters.

Q24. The Latin words of the name given to a human being, Homo Sapiens, include the:

• A. Genus and family
• B. Family and order
• C. Order and class
• D. Genus and class
• E. Genus and species✓

Explanation: The scientific name for humans, Homo sapiens, follows the binomial nomenclature system, which consists of two parts: the genus and the species. In this system, the genus name is capitalized and the species name is lowercase, both in italics. The other options are incorrect because they do not reflect the components of this naming system. 'Genus and family', 'family and order', 'order and class', and 'genus and class' do not align with the binomial naming convention.

Q25. In paper chromatography xanthophylls will give _ colour:

• A. Orange
• B. Grey
• C. Yellow✓
• D. Blue - green
• E. Yellow - green

Explanation: Xanthophylls are yellow-coloured.

Q26. The propulsive movement of the gastrointestinal tract (GI tract) is:

• A. Peristalsis✓
• B. Epiglottis
• C. Antiperistalsis
• D. Anus
• E. None of these options

Explanation: Peristalsis is the contraction of muscle tissue that helps move and break down foodstuffs. The walls of the alimentary canal include layers of smooth muscle controlled by the autonomic nervous system. The alternating contraction and relaxation of these muscles is called peristalsis.

Q27. The Calvin Cycle consist of _ main reactions:

• A. 3✓
• B. 6
• C. 9
• D. 13
• E. 16

Explanation: Calvin cycle is the cycle of chemical reactions where the carbon from the carbon cycle is fixed into sugars.

Q28. Identify the incorrect statement about the Bathyal zone:

• A. It ranges from surface to depth of about 2000 metres
• B. It consists o° pelagic and benthic zones
• C. It is aphetic
• D. It contains producers that prepare food for consumers✓
• E. None of these options

Explanation: Sunlight does not reach this zone, meaning primary production, if any, is almost nonexistent. There are no known phytoplankton or aquatic plants in this zone because of the lack of sunlight necessary for photosynthesis. Hence the correct option is D. As it can be seen in the diagram below, the Baythal zone lies in the aphotic zone

Q29. Deamination in the liver initially produces:

• A. Ammonia✓
• B. Arginine
• C. Ornithine
• D. Urea
• E. Uric acid

Explanation: Deamination is the removal of an amino group from a molecule. Enzymes that catalyze this reaction are called deaminases. In the human body, deamination takes place primarily in the liver. The amino group is removed from the amino acid and converted to ammonia.

Q30. The causes of Cyanosis include:

• A. Deficiency of vitamin C
• B. Varicella-zoster virus
• C. Degeneration of the cartilage of joints
• D. Ventricular septum defect✓
• E. None of these options

Explanation: Cyanosis occurs when oxygen-depleted (deoxygenated) blood, which is bluish rather than red, circulates through the skin. This occurs when there is the mixing of blood which takes place when there is a septal defect in the heart, e.g Ventricular Septal Defect (VSD).

Q31. The prolactin hormone, responsible for the activation of mammary glands to start producing milk, is a hormone of the:

• A. Pituitary gland✓
• B. Pancreas
• C. Thyroid gland
• D. Thymus gland
• E. Adrenal gland

Explanation: In humans, prolactin is produced both in the front portion of the pituitary gland (anterior pituitary gland) and in a range of sites elsewhere in the body. Lactotroph cells in the pituitary gland produce prolactin, where it is stored and then released into the bloodstream.

Q32. Which of the following bones are present in the palm of the hand:

• A. Carpals
• B. Metacarpals✓
• C. Phalanges
• D. Tarsal
• E. Radius

Explanation: The human forelimbs each consist of 30 bones: The humerus, which forms a ball and socket joint with the scapula, and two long parallel bones, the radius and ulna, at its distal end. The radius and ulna join the wrist with eight small carpal bones, which articulate with five metacarpals of the palm. From the palm extend the fingers containing 14 small bones called phalanges, arranged in 5 rows, one row in each finger. The relevant detail for this question is that the bones of the palm are called metacarpals, hence option B is correct.

Q33. Read the passage below to answer the question: Haemophilia is a disorder in which blood fails to clot. Saad, a male haemophiliac, marries Sara, a normal woman and together they have four children, two boys (Ahmed and Ali) and two girls (Alia and Ayesha). None of the children displays the symptoms of Haemophilia. Ahmed, Ali, Ayesha, and Ali all marry normal individuals and have children. None of Ahmed's or Ali’s children, male or female, display symptoms of haemophilia, but the sons of Alia and Ayesha display symptoms of haemophilia while the daughters of Alia and Ayesha do not. Which of the following best explains the reason that Ahmed, Ali, Ayesha and Alia do not display symptoms of haemophilia, even though their father, Saad, is a haemophiliac?

• A. Haemophilia is an X-linked disorder, and Saad can only pass on his Y chromosome
• B. Haemophilia is an X-linked disorder, and even though Alia and Ayesha received a hemophiliac X-chromosome from Saad, Sara gave them a normal X-chromosome✓
• C. Haemophilia is a Y-linked disorder, and therefore cannot be displayed in females
• D. Haemophilia is a Y-linked disorder ,and Ahmed and Ali must have received an X Chromosome from Saad
• E. Haemophilia is an X-linked disorder, and even though Ahmed and All received a Hemophilia X chromosome from Saad, Sara gave them a normal X chromosome

Explanation: Haemophilia is an X-linked chromosome, not a Y-linked chromosome. Daughters of Sara and Saad, Alia and Ayesha receive an X chromosome from both of their parents. Even though hemophilia X-chromosome is received by these daughters from Saad they received normal X from their mother, because of which they do not show any symptoms. Option A is wrong because Saad can pass X as well as Y chromosomes to his offspring. Options C and D are wrong because it is not a Y-linked but an X-linked disease. Option E is wrong because Ahmed and Ali can not receive an X chromosome from Saad (their father), they should receive a Y chromosome, for them to be male.

Q34. Haemophilia is a disorder in which blood fails to clot. Saad, a male haemophiliac, marries Sara, a normal woman and together they have four children, two boys (Ahmed and Ali) and two girls (Alia and Ayesha). None of the children display the symptoms of haemophilia. Ahmed, Ali, Alia, and Ayesha all marry normal individuals and have children. None of Ahmed’s or Ali’s children, male or female, display symptoms of haemophilia, but the sons of Alia and Ayesha display symptoms of haemophilia while the daughters of Alia and Ayesha do not.If one of Ali’s daughters marries a normal man, what is the probability that one of their children will display symptoms of haemophilia?

• A. 0%✓
• B. 25%
• C. 50%
• D. 5%
• E. 100%

Explanation: Ali has the normal allele for haemophilia XHY. He married a normal female XHXH. Their daughter would have normal alleles XHXH. She married a normal man XHY. Their children will all be normal.

Q35. Read the passage below to answer the question: Hemophilia is a disorder in which blood fails to clot. Saad, a male hemophiliac, marries Sara, a normal woman and together they have four children, two boys (Ahmed and Ali) and two girls (Alia and Ayesha). None of the children display the symptoms of Hemophilia. Ahmed, Ali, Ayesha, and Ali all marry normal individuals and have children. None of Ahmed or Ali’s children, male or female, display symptoms of hemophilia, but the sons of Alia and Ayesha display symptoms of hemophilia while the daughters of Alia and Ayesha do not. Which of the following individuals are heterozygous for hemophilia:

• A. Saad, Ahmed, and Ali
• B. Ahmed, Ali, Alia, and Ayesha
• C. Saad and Sara
• D. Alia and Ayesha✓
• E. Ahmed and Ali

Explanation: Male can’t be heterozygous or homozygous because they can only have one allele. Females can possibly be homozygous or heterozygous. Heterozygous are those females that are carriers as we know that Alia and Ayesha do not show any symptoms.

Q36. Which of the following would be most likely to occur in an ecosystem:

• A. As the number of prey decreases, the number of predators increases.
• B. As the number of predators increases, the number of prey increases.
• C. As the number of prey decreases, the number of predators decreases.✓
• D. As the number of prey increases, the number of predators decreases.
• E. As the number of predators decreases, the number of prey decreases.

Explanation: Option C is correct because as the prey decreases, the food for predators decreases thus decreasing their numbers.

Q37. Which biome contains maples, oaks, and bears:

• A. Tundra
• B. Tropical rainforest
• C. Temperate grasslands
• D. Taiga
• E. Deciduous forest✓

Explanation: The correct answer is the Deciduous forest. This biome is known for its four distinct seasons, rich soil, and trees like maples and oaks that shed their leaves annually. It supports a variety of wildlife, including black bears that feed heavily in preparation for hibernation. The other options are incorrect because:Tundra: Characterized by cold climates and limited vegetation, mainly mosses and lichens, not maples or oaks.Tropical rainforest: Known for its biodiversity and constant warm temperatures, but it does not support maples, oaks, or bears.Temperate grasslands: Dominated by grasses and lack significant tree cover, including maples and oaks.Taiga: A biome with coniferous forests, primarily pines and spruces, unlike the broadleaf trees of the deciduous forest.

Q38. The major sign and symptoms of microcephaly is:

• A. Sexual defects
• B. Excessive number of toes
• C. Mental retardation
• D. Small skull in proportion to the normal body size✓
• E. Split in upper lip and gap in the roof of mouth

Explanation: Microcephaly is a neurological condition in which a baby's head is much smaller than expected for the baby's age. The head circumference is typically below the third percentile for the baby's sex and age. Microcephaly can be caused by a variety of genetic and environmental factors, and it can be associated with a range of developmental disabilities.

Q39. The reaction involved in chemotrophic nutrition is:

• A. 6CO2 + 12H2O + light + chlorophyll -> C6H12 + 6H2O + 6CO2
• B. 2H2S + CO2 + light -> (CH2O)n + H2O + 2S
• C. NH4 + 3O2 + light -> 2NO2 + 2H2O + 4H+ + energy✓
• D. CH3COOH + enzyme -> CH3CHO + CO2
• E. 5GA3P + 3ATP -> 3RuBP + 2Pi

Explanation: The word Chemoautotrophic nutrition means energy produced through chemical reactions taking place. The primary work is on inorganic compounds used to synthesise different organic compounds. The reaction involved in chemotrophic nutrition is: NH4 + 3O2 + light -> 2NO2 + 2H2O + 4H+ + energy

Q40. Catenation is a process in which carbon shows the properties of:

• A. Making single bond
• B. Hybridization
• C. Making chains or rings of carbon atoms✓
• D. Isomerism
• E. Breaking of bonds

Explanation: Catenation is the process by which an atom is able to form a bond with another atom of its kind. Carbon possesses this ability hence is able to form ringed structures.

Q41. The maximum number of electrons that an orbital can accommodate is /are:

• A. 0
• B. 1
• C. 2✓
• D. 3
• E. 4

Explanation: Option A: No orbital contains zero electrons. Option B: Degenerated orbitals can be singly filled. Option C: Maximum number of electrons that an orbital can accommodate is 2. Option D: No orbital contains 3 electrons. Option E: No orbital contains 6 electron.

Q42. Which of the following is not a nucleophile?

• A. NH3
• B. OH
• C. CN-
• D. Br2✓

Explanation: Br₂ is not a nucleophile because:No Significant Negative Charge:Nucleophiles are electron-rich species that donate electrons.Br₂ is a neutral molecule with no formal negative charge, making it less likely to donate electrons.Weak Electron Donation Ability:Even though Br atoms have lone pairs, they are held tightly and not readily available for donation.Instead, Br₂ tends to act as an electrophile (electron acceptor), especially in reactions like electrophilic addition.Polarizability but No Strong Nucleophilic Character:Br₂ is a polarizable molecule, meaning it can momentarily develop dipoles, but this does not make it a nucleophile.In reactions, Br₂ often undergoes heterolytic cleavage, forming Br⁺ (electrophile) and Br⁻ (nucleophile), where only Br⁻ is nucleophile.

Q43. Chlorine is manufactured commercially by the electrolysis of aqueous sodium chloride (brine). Which other products are made in this process?

• A. Hydrochloric acid and hydrogen
• B. Hydrogen and sodium
• C. Hydrogen and sodium hydroxide✓
• D. Sodium and sodium hydroxide
• E. Hydrochloric acid and sodium

Explanation: Gas extraction: Chlorine can be manufactured by the electrolysis of a sodium chloride solution (brine), whichis known as the Chlor Alkali process. The production of chlorine results in the co-products of caustic soda (sodium hydroxide, NaOH) and hydrogen gas (H2).

Q44. Sodium reacts with water more vigorously than lithium because it:

• A. Has a higher atomic weight
• B. Is more electronegative
• C. Is more electropositive✓
• D. Is a metal
• E. Has a high melting point

Explanation: Sodium reacts more vigorously with water than lithium primarily because sodium is more electropositive. Electropositivity increases as you move down a group in the periodic table, which means sodium, being below lithium, loses electrons more easily. This increased tendency to lose electrons results in a more vigorous reaction with water. Other factors such as atomic weight, electronegativity, and melting point are not the primary reasons for this difference in reactivity. All alkali metals including sodium and lithium are metals, so this characteristic is not a differentiating factor either.

Q45. The crystals formed as a result of vander Waals interactions are:

• A. Molecular crystals✓
• B. Covalent crystals
• C. Metallic crystals
• D. Ionic crystals
• E. None of these

Explanation: Molecular crystals have Vander Waal forces between them. Covalent crystals have strong covalent bonds between their structures. Ionic crystals are bound by ionic bonding. Metallic bonds are bound by strong electrostatic attraction between positively charged ions and electrons dispersed in the matrix.

Q46. Which of the following statements about H2S is false?

• A. It is a covalent compound
• B. It is a gas with bad smell
• C. It is a stronger reducing agent than H2O
• D. It is a weak base in water✓

Explanation: H2S acts as weak acid in water, not as a weak base. In H2S, the influence of the nucleus is less and hence, it can give away its electrons.

Q47. The raindrop acquires a spherical shape and ink spread over blotting paper due to:

• A. Surface tension✓
• B. Adhesive forces
• C. Viscosity
• D. Polarity
• E. Latent heat of vaporization

Explanation: A raindrop falling through the atmosphere forms a roughly spherical structure due to the surface tension of water. This surface tension is the “skin” of a body of water that makes the molecules stick together. The cause is the weak hydrogen bonds that occur between water molecules.

Q48. 950 torr corresponds to:

• A. 3.5 atm
• B. 1 atm
• C. 3 atm
• D. 1.25 atm✓
• E. 2.25 atm

Explanation: 1 atm = 760 torr To convert torr into atm Value of torr is divided by 760 950/760 = 12.5.

Q49. The enthalpy change accompanying the gain of an electron by a neutral gaseous atom to form a negative ion is called:

• A. Ionization potential
• B. Electronegativity
• C. Electron affinity✓
• D. Lattice energy
• E. Potential energy

Explanation: When an electron is added to a neutral gaseous atom to convert it into a negative ion, the enthalpy change accompanying the process is called Electron affinity enthalpy. Ionization potential, in chemistry, is the amount of energy required to remove an electron from an isolated atom or molecule. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. Lattice energy is defined as the energy required to separate a mole of an ionic solid into gaseous ions. Potential energy is energy that is stored – or conserved - in an object or substance.

Q50. Sigma bond is formed by?

• A. Transferring the electrons
• B. Head on overlapping✓
• C. Mutual but unequal sharing of electrons
• D. Parallel overlapping
• E. All of the above

Explanation: Hybridization: Electron cloud overlaps at the time of bonding at the atomic level to form new orbitals called hybrid orbitals. Two types of bonds can be observed between hybrid orbitals: the Sigma bond and the Pi bond.

Q51. The heat of a reaction can be calculated by using:

• A. Joule's Law
• B. Ohm's Law
• C. Hess's Law✓
• D. Faraday's Law
• E. Boyle's Law

Explanation: Hess' law states that the change of enthalpy in a chemical reaction (i.e. the heat of reaction at constant pressure) is independent of the pathway between the initial and final states. In other words, if a chemical change takes place by several different routes, the overall enthalpy change is the same, regardless of the route by which the chemical change occurs (provided the initial and final conditions are the same). Hess’s law allows the enthalpy change (ΔH) for a reaction to be calculated even when it cannot be measured directly.

Q52. According to the law of mass action,“The rate of chemical reaction” is proportional to the:

• A. The amount of product formed
• B. Product of the molar concentration of reactants✓
• C. The initial concentration of reactants
• D. Catalyst
• E. Pressure

Explanation: The speed at which the reactants are converted to products is called the rate of reaction. There are many factors that affect the speed of conversion of reactants into products:Nature of reaction: The state and number of reactants and complexity of reaction can affect the rate of reaction.Effect of concentration: From the law of mass action, the rate of reaction is directly proportional to the concentration of reactants, that is, the rate of reaction increases with the increase in the concentration of reactants.Pressure: The concentration of reactants can be increased by pressure. Hence, when pressure is increased the speed of reaction also increases.Catalyst: It can increase speed in both reverse and forward directions. This gives another path having low activation energy.Temperature: The reaction which takes place at a high temperature has more energy than a reaction at a low temperature. Now, we have to know what the law of mass action states which will give us a clearer answer to this question.The law of mass action states that, at a given temperature, the rate of a chemical reaction is directly proportional to the product of the molar concentrations of the reactants with their powers raised to their stoichiometric coefficient. The molar concentration of the reactant is also known as the: Q. Hence the correct option is B.

Q53. For the reaction: N2 + 3H2 ⇌ 2NH3 .The production of NH3 will be favored at:

• A. High pressure and catalyst✓
• B. Low pressure only
• C. Low pressure and catalyst
• D. High pressure only
• E. Catalyst only

Explanation: The forward reaction forms fewer moles of gas (4 → 2), so high pressure shifts equilibrium toward NH₃. A catalyst increases the reaction rate but does not change equilibrium position. Therefore, maximum ammonia production is achieved using high pressure along with a catalyst.

Q54. The sum of the exponents of the molar concentration of the reactants is equal to:

• A. Molecularity
• B. Polarity
• C. Activation energy
• D. Rate of reaction
• E. Order of reaction✓

Explanation: The sum of exponents of the molar concentration of reactants in the reaction equation is called the “order of reaction”.Activation energy is the minimum threshold of energy that should be achieved to initiate the reaction. The rate of reaction is the change of concentration of reactants/products per unit time. Polarity implies the dipole character of the compound.

Q55. Nascent hydrogen used in formation of methane, is obtained from the reaction of:

• A. NaHCO3 with Zn
• B. HCl with Zn✓
• C. KOH with Zn
• D. H2O with Zn
• E. CH3I with Zn

Explanation: Zn + HCl = ZnCl + H2

Q56. “Zymase”- a group of 14 enzymes used in the fermentation of starch, is present in:

• A. Bacteria
• B. Yeast✓
• C. Fungi
• D. Algae
• E. Virus

Explanation: Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide. It occurs naturally in yeasts. Zymase activity varies among yeast strains. Zymase is also the brand name of the drug pancrelipase.

Q57. The general formula for an aldehyde is:

• A. R-OH
• B. R-COOH
• C. R-CO-R
• D. R-X
• E. R-CHO✓

Explanation: Aldehydes and ketones have a carbonyl group (C=O) as a functional group. A ketone has two alkyl or aryl groups attached to the carbonyl carbon (RCOR’). The simplest ketone is acetone, which has two methyl groups attached to the carbonyl carbon (CH3COCH3).An aldehyde is similar to a ketone, except that instead of two side groups connected to the carbonyl carbon, they have at least one hydrogen (RCOH or R-CHO). The simplest aldehyde is formaldehyde (HCOH), as it has two hydrogens connected to the carbonyl group. All other aldehydes have one hydrogen bonded to the carbonyl group, like the simple molecule acetaldehyde, which has one hydrogen and one methyl group (HCOCH3).The carbonyl carbon in both aldehydes and ketones is electrophilic, meaning that it has a dipole due to the electronegativity of the attached oxygen atom. This makes the carbonyl carbon an ideal target for nucleophiles in a nucleophilic addition reaction. During this reaction, the nucleophile, or electron donor, attacks the carbonyl to form the tetrahedral intermediate. The negatively charged oxygen accepts a hydrogen ion to form a hydroxyl group.Typically, nucleophiles possess a negative charge or lone pair on a heteroatom, which can take several forms (OH-, RO-, CN-, R3C-, RNH2, ROH). For primary amines (RNH2), the reaction does not stop at the formation of the tetrahedral intermediate with a hydroxyl group. Rather, an elimination reaction occurs that produces a double-bonded carbon and nitrogen functional group known as an imine. Understanding the reactions that aldehydes and ketones can undergo provides a way to differentiate between these similar organic compounds.

Q58. When an element exists in more than one crystalline form, the phenomenon is termed as:

• A. Isomorphism
• B. Allotropy✓
• C. Isomerism
• D. Anisotropy
• E. Enthalpy

Explanation: Allotropy is the correct answer because it describes the ability of an element to exist in multiple forms or structures in the same physical state, such as carbon which can be found as diamond, graphite, and graphene.Isomorphism is incorrect as it refers to different substances with the same crystal structure. Isomerism is about different structural arrangements in organic compounds, not crystalline forms. Anisotropy deals with directional properties and not multiple forms of an element. Enthalpy involves thermodynamic measurements, not crystalline structures.

Q59. The formula of "Plaster of Paris" is:

• A. CuSO4.5H2O
• B. CaSO2.1/2H2O
• C. (CaSO4).2H2O✓
• D. MgSO4.7H2O
• E. Na2SO4.H2O

Explanation: (CaSO4).1/2H2O is the formula of "Plaster of Paris" also known as gypsum.

Q60. Linear combination of atomic orbitals (LCAO) results in the formation of:

• A. Sigma bond
• B. Pi bond
• C. Bonding molecular orbitals only
• D. Bonding and antibonding molecular orbitals✓
• E. All of these options

Explanation: According to Molecular Orbital Theory (MOT), two atomic orbitals overlap resulting in the formation of molecular orbitals. Number of atomic orbitals overlapping together is equal to the molecular orbital formed. The two atomic orbital thus formed by LCAO (linear combination of atomic orbital) in the same phase or in the different phase are known as Bonding Molecular Orbital (BMO) and Antibonding Molecular Orbitals (ABMO) respectively.

Q61. Given the equation:C3H8(g) + 5O2(g)—--> 3CO2(g) + 4H2O(g)At STP, how many liters of O2(g) are needed to completely burn 5.0 liters of C3H8 (g)?

• A. 5.0
• B. 10
• C. 10.5
• D. 15
• E. 25✓

Explanation: Volume -Volume stoichiometric relationship is shown which states that gasses always react in the ratio of small whole numbers by volume Solution: Molecules of C3H8= 1 Molecules of oxygen=5 Litres of C3H8 were given=5 Litres of oxygen given= x C3H8 5O2 1 5 5 X (Cross multiply) X=25 litres of oxygen is required.

Q62. If NaCl produced in the equation:FeCl3 + NaOH —-->Fe(OH)3 + NaClwas dissolved in water to make a liter of solution, the molarity would be:

• A. 0.1M
• B. 3M✓
• C. 8M
• D. 0.5M
• E. 1.5M

Explanation: To get the molarity we need to divide the number of moles of NaCl by the volume of the solution Molar mass of NaCl= 23+35.5= 58.5 Molar mass of H2O= 2+16=18 18/58.5 = 0.30 Ans= 3M

Q63. When 18 ×10-3 moles/dm3 of acetic acid react with 22×10-3 moles/dm3 of ethyl alcohol to form 40×10-3 moles/dm3 of ethyl acetate and 40×10-3 moles/dm3 of waterFind the value of equilibrium constant (Kc)

• A. 4.04✓
• B. 3.14
• C. 3.04
• D. 2.02
• E. 1.04

Explanation: Kc= Concentration of products / Concentration of Reactants. Reactants = acetic acid and ethyl alcohol Products = ethyl acetate and water Multiplication product of products (40 × 40 =1600) Divide by multiplication product of reactants (18× 22= 396) 1600/396= 4.04.

Q64. Harmful and undesirable reaction of metal when exposed to atmosphere or any chemical agent is known as:

• A. Allotropy
• B. Electroplating
• C. Collision
• D. Cracking
• E. Corrosion✓

Explanation: Gradual deterioration of metals caused by the action of air, moisture, or a chemical reaction (such as an acid) on their surface.

Q65. What is the product of both fermentation reactions and fractional distillation?

• A. An ester
• B. An acid
• C. An alcohol✓
• D. A soap
• E. As base

Explanation: Ethyl alcohol can be obtained by fermentation of starch, fermentation of molasses and fractional distillation of pyroligneous acid (obtained through destructive distillation of wood) gives Methyl alcohol.

Q66. The basic functional unit of human kidney is

• A. Nephridia
• B. Loop of Henle
• C. Pyramid
• D. Nephron✓

Explanation: A nephron is a unit of structure and function in a kidney. A kidney contains about a million nephrons, each approximately 3 cm long. A nephron is a long tubule differentiated into four regions having different anatomical features and physiological role : Bowman’s capsule, proximal convoluted tubule (PCT), loop of Henle, and distal convoluted tubule (DCT). The latter opens into one of the collecting ducts. Nephridia are the excretory organs of annelids.

Q67. Which gas is likely to deviate most from ideal gas behavior?

• A. HCl✓
• B. He
• C. CH4
• D. N2
• E. O2

Explanation: No gas is ideal because they show deviations. But those gasses that have more molecular mass than others will deviate the most from ideal gas behavior.

Q68. Purification of bauxite whose major impurity Is silica (SiO2) is carried out through:

• A. Baeyer’s Method
• B. Hall’s Method
• C. Serpek’s Method✓
• D. Contact Method
• E. Electrolytic Method

Explanation: Serpek's method is used for the purification of bauxite if it contains an excess amount of silica (SiO2). The powdered bauxite is mixed with carbon and heated up to 1800˚C and a current of nitrogen is passed, aluminum nitride is obtained. Silica is converted into silicon (Si).

Q69. The range of pH below_ and above _of soil represents its sterility.

• A. 5…..10
• B. 10…5
• C. 3….10✓
• D. 10…3
• E. 5…3

Explanation: Soil's highly acidic and hence sterile.

Q70. Due to the magnetic force, a positively charged particle executes uniform circular motion within a uniform magnetic field "B". If the charge is "q" and the radius is path "r", which of the following expression gives the magnitude of momentum?

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

Explanation: Momentum= mvFor a charged particle in a uniform circular motion, the required centripetal force is provided by a magnetic force equal to B*q*v.So, mv2/r = BqvWhich simplifies to mv=qBrHence Option A is the correct answer.

Q71. A transverse wave on a long horizontal rope with a wavelenght of 8m 2m/s. At t = 0, a particular point on the rope has a vertical displacement of where A is the amplitude of the wave. At what time the vertical displacement of same point on the rope be —A?

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

Explanation: The first thing to do while approaching this question is to figure out the period.v=λ/TT=8/2=4sGoing from amplitude ‘A’ to ‘-A’ takes half the period.So 4/2=2 seconds hence the correct answer is D.

Q72. An object Is placed 60 cm in front of a concave spherical mirror whose focal lenght is 40cm. which of the folowing best described the image?

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

Explanation: Substituting values into the formula 1/f= 1/v - 1/u1/-40= 1/v - 1/601/v= 1/60 - 1/401/v= -1/120v= -120 cmSince the object is placed between f and 2f, the image formed will be real (refer to the table) and 120 cm from the mirror. Therefore option D is correct.

Q73. An object is placed 60 cm from a spherical convex mirror. If the mirror forms a virtual image of 20 cm from the mirror, what is the magnitude of the mirror’s radius of curvature:

• A. 7.5 cm
• B. 15 cm
• C. 30 cm
• D. 60 cm✓
• E. 120 cm

Explanation: We can find focus coordinate from mirror equation: 1/u + 1/v = 1/f as the image is virtual, v is negative. And we find: 1/f = 1/60 - 1/20 = -2/60 = - 1/30 Hence, the focus is at 30 cm from the mirror. Focus and radius of curvature are connected as: R= 2f = 60 cm.

Q74. Find the unit vector paralel to the vector: B = 6i + 12j - 4k.

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

Explanation: For the unit vector, we have to simply divide the vector by its magnitude.The magnitude of a vector parallel to B = √ 6²+12²+4² = 14

Q75. A shot leaves a gun at the rate of 160m/s. Calculate the greatest distance to which it could be projected and the height to which it would rise? (g=10m/s2).

• A. 1560m, 540m
• B. 2560m, 640m✓
• C. 3560m. 740m
• D. 4560m, 840m
• E. 9595m, 348m

Explanation: R= u²sin2θ/gFor maximum range θ=45So 160²/10= 2650This alone is sufficient to enable us to narrow our answer to just B (do not waste time finding height while attempting the actual exam!)For height, H= u²sin²θ/2gat θ=45 H=u²/4g160²/4*10=640Which again confirms option B to be correct.

Q76. A car covers the first half of a certain distance with a speed V1 and the second half, with a speed V2. Find the average speed during the whole journey?

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

Explanation: Average speed= total distance/total timeThe car’s journey can be divided into two equal parts of distance ‘d’. Since both distances are equal,Total distance= 2dTotal time= d/v1 (for first part) and d/v2 (for second part)Average speed= 2d / d(1/v1+1/v2)d cancels out leaving 2 / (v1+v2/v1v2)Which can be written as 2v1v2 / v1+v2That is consistent with option B.

Q77. The quantity of heat required to raise the temperature of one mole of a substance through 1K, and its units are J - mole-1 K-1 is called:

• A. Carnot Engine
• B. Molar specific heat✓
• C. Kinetic specific heat
• D. General Gas Law
• E. Boyle's Law

Explanation: The question describes the definition of molar specific heat, which matches option B.

Q78. A rescue helicopter drops a package of emergency ration to a stranded party on the ground. If the helicopter is traveling horlzontaly at 40m/s at height 100m above the ground, where does the package strike the ground relative to the point at which it was release.

• A. 120m
• B. 130m
• C. 140m
• D. 180.7m✓
• E. 200.3m

Explanation: This is a case of half-projectile motion.First, let’s find out the time taken for the package to strike the ground.s=ut+1/2at²100=0 + ½ (10) t² (vertical velocity is 0 at the highest point in full projectile & starting point in half-projectile)100=5t²t²=20 so t=√20Now, assuming there is no horizontal force, horizontal velocity stays constant So distance= velocity x timeOr 40x√20= 180.7 That gives option D as the correct answer.

Q79. The radius of the moon is 27% of the earth's radius and it's mass is 1.2% earth's mass. Find the acceleration due to gravity on the surface of the moon.

• A. 0.431 m/s2
• B. 1.615 m/s2✓
• C. 2.431 ms2
• D. 3.615 m/s2
• E. 4.431 m/s2

Explanation: Acceleration due to gravity on Earth= GMe/Re² = 9.81 (Me= mass of Earth, Re= radius of Earth)For moon g(moon)= G(0.012Me)/(0.27Re)²g(moon)= GMe/Re² * 0.1646g(moon)= 9.81 x 0.1646 = 1.615 m/s² This makes option B to be the correct choice for this question.

Q80. Two capacitors C1 = 2µ and C2 = 4µ F are connected in series across in a 100V supply. Find the effective capacitance.

• A. ½ µF
• B. 3/2 µF
• C. 5/2 µF
• D. 4/3 µF✓
• E. 2 µF

Explanation: Recall that the effective capacitance of capacitors in series is the reciprocal of the sum of reciprocals of individual capacitors (just like resistors in parallel)Therefore,1/Ceffective = 1/C1 + 1/C21/Ceffective = ½ +¼ 1/Ceffective = ¾C effective= 4/3 µF Hence option D is the correct answer.

Q81. A sample of an ideal gas occupies a volume "V" at pressure "p" and absolute temperature "T". The mass of each molecule is 'm'. If "k" is the Boltzmann constant then the density of the gas is:

• A. mkT
• B. P/KT
• C. P/kTV
• D. mP/kT✓
• E. 2mPT/k

Explanation: PV= NkTV= NkT/PThe mass of one molecule of gas is ‘m’So total mass= N*mThe density of the gas is = total mass/ total volumeDensity= N*m/ (NkT/P)Which simplifies to mP/kT That is consistent with option D.

Q82. A car is waiting at a traffic signal and when the signal turns green, the car starts ahead with a constant acceleration of 2 m/s2. At the same time as a bus traveling with a constant speed of 10 m/s overtakes and passes the car. How far beyond its starting point will the car overtake the bus?

• A. 40M
• B. 30M
• C. 90M
• D. 120M
• E. 100M✓

Explanation: To approach this question, remember that at the point when the car overtakes the bus, both vehicles be at the same distance from the starting point (ie have the same displacement)Now, s=ut + ½ at²For bus Sв=10t (since speed is constant, a=0)For car Sc= ½ (2) t² (u=0 as car starts from rest)Equating the two displacements, we get t²=10tWhich gives t=0 t=10 secondsThis means that 10 seconds after the journey, the car overtakes the bus.Simply substitute the time to find displacement of the car/bus (both will have the same displacement at this point)Sв=10t S= 10*10 = 100M Hence option E is correct.

Q83. When a car moves with constant acceleration, the velocity-time graph is a:

• A. Straight line✓
• B. Parabola
• C. Horizontal line
• D. Exponential curve

Explanation: Explanation:The slope of the velocity - time graph is equal to acceleration. As body moves with constant acceleration, the velocity-time graph will be a straight line. Slope = Constant

Q84. Assume that you have two balls of identical volume, one weighing 2 Newtons and the other 10 Newtons. Both are falling freely after being released from the same point simultaneously. Which of the following will then be true: I. The 10 N ball falling freely from rest will be accelerated at a greater rate than the 2 N ball II. At the end of the 4s of freefall, the 10 N ball will have 5 times the momentum of the 2 N ball III. At the end of the 4s of free fall, the 10 N ball will have the same kinetic energy as the 2 N ball IV. The 10 N ball possesses greater inertia than the 2 N ball

• A. I, Il and Ill only
• B. I and II only
• C. II and IV only✓
• D. IV only
• E. None of these

Explanation: Acceleration of free fall acts equally on all masses, this is why both objects despite having different masses have the same speed at any point in time. Statement II is correct because two objects have the same velocity but one having 5 times more mass than the other will have 5 times more momentum than the other object. Statement IV is also correct because inertia depends upon mass since a 10N ball has a higher mass it will have greater inertia. Statement III is wrong because objects have different masses so their kinetic energy can not be the same. Statement I is wrong because objects accelerate irrespective of their masses as mentioned before.

Q85. A ball moving horizontally with speed ‘v’ strikes the bob of a simple pendulum at rest. The mass of the bob is equal to that of the ball if the collision is elastic the bob will rise to a height:

• A. v2/g
• B. v2/2g✓
• C. v2/4g
• D. v2/8g
• E. v2/7g

Explanation: From the conservation of linear momentum before and after the collision, mv=(m+m)v′ ⟹v′=v/2 All the initial kinetic energy gets converted to gravitational potential energy at the maximum height. Thus, ½ (2m)v2=(2m)gh =>V2/2g

Q86. A point source of light is placed at the principal focus of a concave lens. Which of the following will be true of the refracted light?I- I will diverge.II- It will be paralel to be principle axis.III- It will seem to come from a point 1/2 of the radius of curvature from the lens.IV- It will converage.

• A. I, II and III Only
• B. I and III only
• C. II and IV only
• D. IV only
• E. None of the above✓

Explanation: Statement I is correct because a concave lens is diverging.Statement II is incorrect because the refracted rays will not be parallel to the principal axis.Statement III is incorrect because this is not true.Statement IV is incorrect because a concave lens is diverging while a convex lens is converging. Judging from our deductions about the statements, none of the options A, B, C, or D are correct. Hence option E is the right answer.

Q87. The dimensions of volume and acceleration (respectively) are:

• A. LT1 and LT2
• B. LT2 and LT-1
• C. L3 and LT-2✓
• D. L4T-1 and LT
• E. LT3 and T2

Explanation: The volume is simply a product of three dimensions of length. Therefore, the dimensions should be L³.Acceleration=change in velocity/timeThe dimensions of velocity and time are LT-1 and T respectively.LT-1/T = LT-2. This is consistent with option C.

Q88. A vector such as the velocity of a body undergoing uniform translational motion, which can be displaced parallel to itself and applied to any point known as:

• A. Unit vector
• B. Free vector✓
• C. Null vector
• D. Position vector
• E. Resultant vector

Explanation: Option B is the correct answer because a free vector is one whose action is not confined or associated with a unique line in space. For a body in uniform translational motion, the velocity of any point in the body may be taken as a vector and this vector will equally well describe the velocity of all points in the body. Hence, the velocity of such a body may be represented by a free vector.

Q89. What is the flux density at a point 3 cm from the long straint wire, when there is a current of 25A in the wire? (μo = 4π x 10-7)

• A. 0 .23 x 10-1 T
• B. 1.67 x 10-4 T✓
• C. 2.99 x 10-6 T
• D. 3.63 x 10-8 T
• E. 9.99 x 10-7 T

Explanation: The flux density B from a straight current-carrying wire = μI/2πr4πx10-7 x 252πx0.03= 1.67 x 10-4 Thus option B is the correct answer.

Q90. If an object is placed 30 cm from a convex loin whose local enuth is 15 cm, the size of the image compared to the size of the object will be approximately:

• A. Twice as large
• B. More than twice as large
• C. 1.5 times as large
• D. Smaller
• E. The same size✓

Explanation: For an object placed at twice the focal length of a convex lens, the image will be inverted, real, and the same size. So the correct answer here should be E. This can be confirmed using a ray diagram.

Q91. When a conductor of cross-sectional area 5.0 x 104m2 carries a current of 6.0A,the drift velocity of the conduction electrons is 1.2x10-4 ms-1 . What is the number density (number per unit volume) of the conduction electrons?

• A. 4.0 x 10-28 m-3
• B. 1.6 x 10-27 m-3
• C. 2.5 x 1027 m-3
• D. 6.3 x 1028 m-3✓
• E. 1.3 x 1034 m-3

Explanation: Recall that the formula for the drift velocity of charged particles isv= I/nAqMaking n (number density) the subject we get n= I/ AqvSubstituting the valuesn= 6/ 0.0005x1.6x10-19 * 0.00012n= 6.25 x 1026The closest answer to this value would therefore be D.

Q92. A thermocouple is connected cross a galvanometer of resistance 30Ω. One junction is immersed in water at 373 K and the other in ice at 273K. The e.m.f of the thermocouple is 90μ V for each 1K difference in temperature between the junctions, and the thermocouple resistance is 6Ω. What current will flow in the galvanometer?

• A. 1.8μA
• B. 250μA✓
• C. 300μA
• D. 1.5mA
• E. 1.8mA

Explanation: For every 1K difference in temperature, the emf of the thermocouple is 90µV.The difference in temperature between the junctions= is 373-273=100K.So the emf would be equal to 9000μV.The thermocouple resistance is 6Ω and the galvanometer resistance is 30Ω. Hence total resistance is 36ΩSo current through galvanometer I=V/RI=9000/36=250μA. Therefore the correct answer is B.

Q93. The first law of thermodynamics may be written as ∆U = Q+W. Where '∆U' is the increase in internal energy of the system, "Q" is the heat transfer to the system and "W" is the external work done on the system. Which of the following is correct for the case of an isothermal expansion of an ideal gas?

• A. W > 0
• B. W = 0
• C. ∆U = 0✓
• D. ∆U > 0
• E. Q = 0

Explanation: The internal energy of an ideal gas= 3/2NkT This shows that the internal energy depends upon the temperature of a gas since all other variables are constant. As long as the temperature does not change, the internal energy is constant. Now, for an isothermal expansion, the temperature is kept unchanged. This means that the change in internal energy is 0. Therefore option C is correct.

Q94. A body of mass 5kg, initially at rest, is moved by a horizontal force of 2N on a smooth horizontal surface. Find the work done by the force in 10s?

• A. 40J✓
• B. 30J
• C. 50J
• D. 20J
• E. 10J

Explanation: Firstly let's find out the acceleration of the body using F=ma (Newton's 3rd law)Now 2=5aa=⅖s= ut + ½ at²s= ½ * ⅖ * 10²s= 20 mNow work done= F * d2x20= 40 J This corresponds to option A.

Q95. A body of mass 5kg, initially at rest, is moved by a horizontal force of 2N on a smooth horizontal surface. Find the work done by the force in 10sec?

• A. 50 units
• B. 75 units
• C. 125 units
• D. 155 units
• E. 40 units✓

Explanation: a = F/m a = 2/5 m/s² S=1/2at² (on the grounds that u is zero) S=1/2*2/5*10² S = 2/10*100 S = 20m W=F.S W=2*20 W=40 J.

Q96. A body start sliding on a rough horizontal surface with a speed of 10 m/s. If the coeficient of friction is 0.2, find the distance travelled by the body before coming to rest. (g = 10 m/s2)

• A. 15m
• B. 25m✓
• C. 35m
• D. 40m
• E. 55m

Explanation: f= μFn = μmgf= 0.2x10mUsing newton’s 3rd law, f=maa=f/mHere the m cancels out and a=2 m/s²Now, using the equation of motion v²=u²+2as0²= 10²+2(-0.2x10)sMaking s the subject, s= 100/4 = 25 m. Hence the correct answer is option B.

Q97. A battery whose e.m.f. Is 40V has an Internal resistance of 5Ω. If this battery is connected to a 15Ω resistor "R", what will be the voltage drop across 'R'?

• A. 10V
• B. 30V✓
• C. 40V
• D. 50V
• E. 70V

Explanation: First, let us calculate the current that flows through the circuit.I=V/R= 40/ (15+5)I= 2 AThe voltage drop across R will be V= 2x15=30 V Therefore option B is the correct answer.

Q98. A particle of charge -0.04C is projected with speed 2 x 104 m/s into a uniform magnetic field "B" of strength 0.5T. If the particle's velocity as it enters the field is perpendicular tp "B", what is the magnitude of the magnetic force on this particle?

• A. 4N
• B. 8N
• C. 40N
• D. 80N
• E. 400N✓

Explanation: Magnetic force on a charged particle in a magnetic field B is equal toFв= Bqv sinΘ=0.5 -0.04x2x104xsin90=400 N Thus the correct answer is E.

Q99. Choose the word most similar in meaning to the following word:AVOID

• A. Reduce
• B. Insist
• C. Compel
• D. Ignore✓

Explanation: Avoid means to stay away from someone or something, or prevent something from happening; to refrain; ignoring something. Option D is correct: Ignore has the same meaning as that of the word avoid. It means to refuse to take notice of or acknowledge, or disregard something intentionally.