Model Paper 3

Chapter 4 · Full Model Papers · 200 questions in the paper · 33 min read

Model Paper 3

What the syllabus asks for 1
  • Zoology 40, Botany 40, Chemistry 50, Physics 50, Mental Agility Test 20, with an explained key

MODEL PAPER 3 — MECEE-BL (Group I). Time: 3 hours. Full marks: 200. Attempt all questions. Each question has four options with one best answer; choose the best and mark it on your answer grid. Each correct answer carries 1 mark and each wrong answer deducts 0.25 mark. Calculators are not allowed; do rough work in the margins. Sit this paper in one uninterrupted sitting, exactly as on the day.

How to score yourself: score = (number correct) − 0.25 × (number wrong). Do not leave blanks — in this marking scheme even a blind guess is worth +1/16 of a mark. Record your correct/wrong/blank counts per subject before you open the key.

This paper follows the official unit weightage exactly:

Subject Qs Per-unit counts in this paper
Zoology 40 Evolution 3 · Diversity 4 · Tissues 4 · Selected animals 6 · Digestive 2 · Respiratory 2 · Circulatory 3 · Excretory 2 · Nervous 2 · Endocrine 2 · Reproductive 2 · Diseases/Immunity 4 · Medical technology 2 · Environment 2
Botany 40 Components of life 2 · Virus/bacteria 2 · Fungi/lichens 2 · Algae/bryophytes 2 · Pteridophytes–angiosperms 3 · Ecology 4 · Cell biology 5 · Genetics fundamentals 2 · Genetic material 4 · Anatomy 3 · Water relations 2 · Photosynthesis/respiration 3 · Growth 1 · Developmental 2 · Applied 3
Chemistry 50 Physical 17 · Inorganic 10 · Organic 17 · Applied 3 · Analytical 3
Physics 50 Mechanics 10 · Heat 7 · Waves/Optics 8 · Current electricity/Magnetism 9 · Electrostatics 4 · Modern 12
MAT 20 Verbal 5 · Numerical 5 · Logical 5 · Spatial/Abstract 5

Zoology (questions 1–40)

  1. The mutation theory of evolution was proposed byaHugo de VriesbWeismanncMendeldLamarck
  2. Analogous organs are illustrated by theaarm of man and wing of batbleg of dog and flipper of whalecheart of frog and mandwings of butterfly and bird
  3. Random genetic drift is most effective inavery large populationsbonly plant populationscpopulations with no variationdsmall populations
  4. A well-developed canal system for water circulation is present in the phylumaAnnelidabPoriferacMolluscadEchinodermata
  5. Flame cells (protonephridia) are the excretory organs ofaPlanariabAscariscearthwormdHydra
  6. The largest phylum of the animal kingdom, in number of species, isaMolluscabChordatacAnnelidadArthropoda
  7. Which of the following is a flightless bird?aPeacockbParrotcOstrichdVulture
  8. Areolar tissue is a type ofaepithelial tissuebmuscular tissuecloose connective tissuednervous tissue
  9. The Haversian system is characteristic ofacartilagebthe spinal cordcthe skindmammalian bone
  10. Thin squamous epithelium, suited for diffusion, lines theaalveoli of the lungsburetercstomachdtrachea
  11. The part of a neuron that normally receives nerve impulses is theadendritebaxoncmyelin sheathdSchwann cell
  12. The sexual cycle (sporogony) of Plasmodium is completed inside theahuman liverbhuman red blood cellscmosquitodhuman spleen
  13. Merozoites released from the liver of man next invade theawhite blood cellsbred blood cellscplateletsdplasma proteins
  14. The earthworm possesses hearts (contractile vessels) numberinga4 pairsb2 pairsc8 pairsd1 pair
  15. The excretory organs of the earthworm are theaMalpighian tubulesbflame cellscsegmental nephridiadgreen glands
  16. The third eyelid of the frog, protective under water, is theatympanumbcorneacnictitating membranediris
  17. The kidney of the adult frog is of the type calledapronephrosbmesonephroscmetanephrosdarchinephros
  18. Trypsin of pancreatic juice is secreted in the inactive form ofatrypsinogenbpepsinogencprorennindenterokinase
  19. A patient's bile duct is blocked by a gallstone. The digestive process most directly impaired by the lack of bile reaching the intestine is theaemulsification and absorption of fatsbdigestion of proteins in the stomachcsecretion of insulindformation of urine
  20. Most of the carbon dioxide in the blood is transported asacarbaminohaemoglobinbbicarbonate ionscdissolved CO₂dcarbonic acid
  21. The vital capacity of the lungs of a normal adult is abouta1200 mLb4600 mLc6000 mLd1500 mL
  22. The bundle of His and Purkinje fibres conduct the cardiac impulse from the AV node to theaSA nodebatriacbraindventricles
  23. A patient with an acute bacterial infection typically shows a raised count of the phagocytic leucocytes calledaneutrophilsblymphocytesceosinophilsdbasophils
  24. Lymph differs from blood mainly in lackingawaterbwhite blood cellscdissolved proteins entirelydred blood cells
  25. Desert mammals have very long loops of Henle, which help them toaproduce a large volume of dilute urinebconserve water by concentrating urinecfilter a larger volume of blood plasmadstore urine for longer in the bladder
  26. The hormone aldosterone increases the reabsorption, in the kidney tubules, ofaglucosebsodium ionscureadamino acids
  27. Coordination of muscular movement, posture and balance is the main function of theacerebellumbcerebrumcmedulladspinal cord
  28. The visual pigment present in the rod cells of the retina isaiodopsinbrhodopsincmelanindcarotene
  29. The hormone often called the emergency (fight-or-flight) hormone isainsulinbthyroxinecoxytocindadrenaline
  30. Oxytocin brings aboutarelease of the ovum (ovulation) from the ovarybproduction of sperms in the seminiferous tubulesccontraction of the uterus and milk ejectionda general increase in the growth of the body
  31. The acrosome at the tip of a sperm is derived from theamitochondriabcentriolecGolgi apparatusdnucleus
  32. In the human menstrual cycle, the surge of LH directly triggersamenstruationbimplantationcdegeneration of the corpus luteumdovulation
  33. Cholera is caused by the bacteriumaSalmonella typhibMycobacteriumcVibrio choleraedPlasmodium
  34. Interferons, released by virus-infected cells, areaantibodies secreted by plasma cellsbantibiotics obtained from certain fungicweakened viruses used as live vaccinesdantiviral proteins protecting neighbouring cells
  35. The antimalarial drug quinine is obtained from the bark ofapoppybneemcCinchonadRauwolfia
  36. Cancerous cells are characterised by the loss ofanucleibcell membranescpigmentsdcontact inhibition of growth
  37. An ECG (electrocardiogram) records the electrical activity of theabrainbheartceye musclesdstomach
  38. DNA fingerprinting identifies individuals by analysing theiraABO and Rh blood groups of the personbpattern of proteins in blood plasmacsequences of RNA found in the cellsdvariable repetitive DNA (VNTR) patterns
  39. Acid rain is caused mainly by the atmospheric pollutantsaCO and CO₂bSO₂ and oxides of nitrogencozoneddust particles
  40. In-situ conservation of a species means protecting itain a zoobin a seed bankcin its natural habitatdin a laboratory

Botany (questions 41–80)

  1. The disaccharide maltose is made up of two units ofaglucose + fructosebglucose + galactosecglucose + glucosedfructose + fructose
  2. An enzyme solution is boiled and then cooled back to body temperature, yet it no longer catalyses its reaction. The best explanation is that heating hasadestroyed the substrate moleculesbdestroyed the three-dimensional shape of the active sitecremoved all the water around the enzymedconverted the enzyme into a carbohydrate
  3. Viruses can multiply onlyain the airbinside living host cellscin dead organic matterdon artificial nutrient agar
  4. In bacteria, respiration (energy release) takes place at thearibosomesbcapsulecflagelladcell membrane (mesosomes)
  5. The cell wall of fungi is composed mainly ofachitinbcellulosecpeptidoglycandlignin
  6. The common edible mushroom Agaricus belongs to the classaAscomycetesbZygomycetescDeuteromycetesdBasidiomycetes
  7. The chloroplast of Spirogyra is characteristicallyacup-shapedbdiscoidcstar-shapedda spiral ribbon
  8. Marchantia, with a flat thalloid body, is a member of theamossesbliverwortschornwortsdalgae
  9. The prothallus of a fern is itsasporophytebgametophytecembryodspore
  10. The pollen grains of Pinus are provided withawings (air bladders)bflagellaca sticky coatdhooks
  11. A papilionaceous (butterfly-shaped) corolla is characteristic of the familyaFabaceaebLiliaceaecBrassicaceaedPoaceae
  12. The ecological niche of a species refers to itsaphysical shelterbfunctional role in the ecosystemcpopulation sizedtotal biomass
  13. A detritus food chain begins withagreen producersbherbivorescdead organic matterdcarnivores
  14. The phosphorus cycle differs from the carbon cycle in being mainly aagaseous cyclebatmospheric cyclecsedimentary cycledmarine cycle only
  15. Epiphytes grow upon other plants only forafoodbsupport and lightcwater from the hosts xylemdmineral salts
  16. The inner membrane of a mitochondrion is folded into theagranabthylakoidsccristaedstroma
  17. Sister chromatids separate and move to opposite poles duringametaphasebtelophasecanaphasedprophase
  18. The amount of DNA in a cell at the G₂ phase, compared with the G₁ phase, isadoublebthe samechalfdfour times
  19. Leucoplasts that store starch are calledachloroplastsbchromoplastscamyloplastsdelaioplasts
  20. The tonoplast is the membrane that surrounds theavacuolebnucleuscmitochondriondchloroplast
  21. Mendel's "law of purity of gametes" is the law ofasegregationbindependent assortmentcdominancedlinkage
  22. Crossing an F₁ hybrid with its recessive parent is called aareciprocal crossbself crosscdihybrid crossdtest cross
  23. Semiconservative replication of DNA was demonstrated experimentally byaMeselson and StahlbHershey and ChasecGriffithdAvery and coworkers
  24. In a nucleosome, DNA is wrapped around a core of proteins calledahistonesbpolymerasescribosomesdligases
  25. The process of translation (protein synthesis) takes place on theaGolgi bodiesblysosomescinner nuclear membranedribosomes
  26. The number of stop (termination) codons in the standard genetic code isaonebtwocfourdthree
  27. Companion cells are intimately associated with theavesselsbtracheidscsieve tube elementsdxylem fibres
  28. Annual rings in a woody stem are produced by the seasonal activity of theaapical meristembcortexcpithdvascular cambium
  29. Lenticels in the bark of a stem help inaphotosynthesisbconduction of watercgaseous exchangedmechanical support
  30. The diffusion pressure deficit (DPD) of a fully turgid cell isamaximumbequal to osmotic pressurecnegativedzero
  31. Plasmolysis of a plant cell occurs when it is placed in aahypertonic solutionbhypotonic solutioncisotonic solutionddistilled water
  32. The first stable compound formed in the Calvin cycle of C₃ plants isaoxaloacetatebphosphoenolpyruvatecglucosed3-phosphoglyceric acid
  33. The stage common to both aerobic and anaerobic respiration isathe Krebs cyclebglycolysiscthe electron transport chaindoxidative phosphorylation
  34. The respiratory quotient (RQ) for the complete oxidation of glucose isa0.7binfinityc1.0d1.33
  35. Cytokinins primarily promote, in plant tissues, the process ofacell elongationbseed dormancyccell divisiondleaf fall
  36. Syngamy (fusion of a male gamete with the egg) produces theaendospermbzygotecsynergiddantipodal cells
  37. A true fruit develops from theaovulebovarycstyledfilament
  38. The polymerase chain reaction (PCR) uses the heat-stable enzymeaDNA ligasebhelicasecrestriction enzymedTaq DNA polymerase
  39. Azadirachtin, a natural biopesticide, is obtained from the treeatobaccobneemctulsiddatura
  40. The somatic hybrid "pomato" (potato + tomato) was produced byaprotoplast fusionbgraftingcmutation breedingdcross-pollination

Chemistry (questions 81–130)

  1. The mass of 0.25 mol of sulphuric acid (molar mass 98 g/mol) isa98 gb49 gc24.5 gd12.25 g
  2. Avogadro's number, the number of particles in one mole, isa6.02 × 10²²b6.02 × 10²³c3.01 × 10²³d1.6 × 10⁻¹⁹
  3. According to Heisenberg's uncertainty principle, it is impossible to determine simultaneously the exact position and the exact ___ of an electron.achargebmasscspindmomentum
  4. The number of neutrons in a deuterium (²H) nucleus isaonebtwoczerodthree
  5. The elements of group 17 of the periodic table are collectively calledaalkali metalsbchalcogenschalogensdnoble gases
  6. An example of a typical ionic compound isaNaClbHCl gascCH₄dCO₂
  7. The hybridisation of the carbon atom in methane isaspbsp²csp³dsp³d
  8. A reducing agent brings about reduction by itself gettingareducedbneutralisedchydrolyseddoxidised
  9. A given volume of hydrogen gas effuses through a pinhole in 20 seconds. The same volume of oxygen (molar masses H₂ = 2, O₂ = 32) under identical conditions takes abouta5 sb80 sc40 sd20 s
  10. 4 g of NaOH is dissolved to make 500 mL of solution. Its molarity isa0.1 Mb0.2 Mc0.4 Md2.0 M
  11. An acidic buffer solution is a mixture ofaa strong acid and its saltba strong base and its saltca weak base aloneda weak acid and its salt with a strong base
  12. Calculate the approximate pH of a 0.1 M solution of acetic acid (Ka = 1.8 × 10⁻⁵) using [H⁺] ≈ √(Ka × c).a1.0b2.9c4.7d7.0
  13. In a titration with potassium permanganate solution, the indicator used isaphenolphthaleinbKMnO₄ itself (self-indicator)cstarch solutiondlitmus
  14. The rate of a certain reaction roughly doubles for every 10 °C rise in temperature. Raising the temperature from 20 °C to 50 °C increases the rate by a factor of abouta2b4c6d8
  15. How much copper is deposited at the cathode when 1 faraday of electricity is passed through copper sulphate solution (atomic mass of Cu = 63.5, Cu is divalent)?a31.8 gb63.5 gc15.9 gd127 g
  16. Given ΔH°f of CO₂ = −393 kJ/mol, of H₂O(l) = −286 kJ/mol and of CH₄ = −75 kJ/mol, the enthalpy of combustion of methane is abouta−890 kJ/molb−965 kJ/molc−604 kJ/mold+890 kJ/mol
  17. A piece of ancient wood shows a carbon-14 activity one quarter of that of living wood. If the half-life of carbon-14 is 5730 years, the age of the wood is abouta5730 yearsb2865 yearsc17,190 yearsd11,460 years
  18. "Dry ice" used for refrigeration is solidacarbon monoxidebcarbon dioxidecnitrous oxidedammonia
  19. Sulphur dioxide bleaches vegetable colours by the process ofaoxidationbdehydrationcneutralisationdreduction
  20. Concentrated nitric acid kept in light turns yellow because of dissolvedaNObN₂OcNO₂dNH₃
  21. The most reactive halogen isafluorinebchlorinecbrominediodine
  22. Copper pyrites (CuFeS₂) is the chief ore ofaironbzincccopperdlead
  23. The froth-flotation process is used for concentratingasulphide oresboxide oresccarbonate oresdnitrate ores
  24. Rust that forms on iron is chemicallyaFeObFe₃O₄cFe(OH)₂dhydrated ferric oxide, Fe₂O₃·xH₂O
  25. Zone refining is used to obtain ultra-pure samples ofaironbgermanium (for semiconductors)csodiumdcopper for wires
  26. The oxygen-carrying protein stored in muscles isahaemoglobinbchlorophyllcmyoglobindhaemocyanin
  27. Vitamin B₁₂ contains the metalaironbzincccobaltdcopper
  28. An electrophile in an organic reaction is a species that isaan electron-deficient species that seeks an electron pairba neutral molecule with a lone pair onlyca species that readily donates a protonda stable anion carrying extra electrons
  29. Keto–enol tautomerism is exhibited byabenzenebethanolcethyl acetoacetatedethane
  30. Phenol is more acidic than ethanol mainly because the phenoxide ion is stabilised byaits larger sizebhydrationcprecipitationdresonance
  31. A hydrocarbon has the molecular formula C₆H₁₀. Its index of hydrogen deficiency (double-bond equivalents) isa2b1c3d4
  32. Ozonolysis of ethene, followed by hydrolysis, yieldsaacetaldehydebcarbon dioxide onlycformic aciddformaldehyde
  33. Benzene reacts with chlorine in the presence of FeCl₃ to form mainlyahexachlorocyclohexanebchlorobenzenecbenzyl chlorideddichloromethane
  34. The iodoform (yellow precipitate) test is given byamethanolbethanolcpropan-1-oldphenol
  35. Williamson's synthesis is a standard method for preparingaethersbesterscamidesdaldehydes
  36. Phenol on distillation with zinc dust givesatoluenebbenzeneccyclohexanedaniline
  37. The alcohol that is dehydrated most easily by concentrated H₂SO₄ is aaprimary alcoholbmethanolcsecondary alcoholdtertiary alcohol
  38. Commercial formalin, used to preserve biological specimens, is an aqueous solution of about 40% ofaformaldehydebformic acidcacetaldehydedacetone
  39. The Rosenmund reduction converts an acyl (acid) chloride into the correspondingaalcoholbaldehydecalkanedcarboxylic acid
  40. Carboxylic acids react with sodium bicarbonate with brisk effervescence of the gasahydrogenboxygenccarbon dioxidedcarbon monoxide
  41. Sodium acetate heated with soda lime undergoes decarboxylation to giveamethanebethaneccarbon monoxidedmethanol
  42. In aqueous solution, the strongest base among the following isaethylaminebanilinecammoniadacetamide
  43. Hinsberg's reagent, used to distinguish primary, secondary and tertiary amines, isaacetyl chloridebcarbon disulphidecnitrous aciddbenzenesulphonyl chloride
  44. Picric acid, an explosive, is chemicallya2,4,6-trinitrophenolb1,3,5-trinitrobenzenectrinitrotoluenedo-nitrobenzoic acid
  45. Nylon belongs to the class of polymers calledapolyestersbpolyolefinscpolyamidesdacrylics
  46. Sodium benzoate is widely used in foodstuffs as aasweetenerbcolouring agentcpreservativedraising agent
  47. The major constituent (about 60–65%) of Portland cement isasilicabaluminacgypsumdlime (CaO)
  48. In the flame test, sodium salts impart to the flame the colouracrimsonbgreencgolden yellowdviolet
  49. The borax-bead test is used in qualitative analysis for detectingasodium ionsbcoloured metal ions such as Cu²⁺cchloride ionsdcarbonate ions
  50. Halogens present in an organic compound are estimated quantitatively by theaKjeldahl methodbCarius methodcDumas methoddLiebig method

Physics (questions 131–180)

  1. A projectile is fired at 40 m/s at an angle of 30° above the horizontal. Its horizontal range (g = 10 m/s²) is abouta80 mb160 mc69 md139 m
  2. One horse power is approximately equal toa100 Wb550 Wc746 Wd1000 W
  3. A constant force of 20 N acts for 0.5 s on a 2 kg body initially at rest (no friction). The speed it acquires isa10 m/sb2.5 m/sc20 m/sd5 m/s
  4. A man of mass 50 kg climbs to a height of 10 m in 5 s (g = 10 m/s²). His average power isa1000 Wb500 Wc2500 Wd100 W
  5. A spinning skater with moment of inertia 6 kg m² rotates at 2 rad/s. On pulling in her arms the moment of inertia falls to 3 kg m². Her new angular speed isa1 rad/sb2 rad/sc6 rad/sd4 rad/s
  6. The SI unit of the coefficient of viscosity is theapoisebnewtoncpascaldpascal-second (Pa·s)
  7. A particle executes SHM with a time period of 0.5 s. Its frequency isa0.5 Hzb1 Hzc2 Hzd4 Hz
  8. A car negotiates a flat circular curve of radius 40 m. If the coefficient of friction between tyres and road is 0.4 (g = 10 m/s²), the maximum safe speed is abouta8 m/sb13 m/sc16 m/sd20 m/s
  9. The speed with which a satellite orbits close to the Earth's surface is abouta11.2 km/sb7.9 km/sc3.0 km/sd1.0 km/s
  10. A steel wire of cross-sectional area 1 × 10⁻⁶ m² carries a load of 200 N. If the Young modulus of steel is 2 × 10¹¹ Pa, the strain produced isa0.01b0.1c0.001d1.0
  11. The triple point of water on the kelvin scale is fixed at exactlya273.15 Kb0 Kc273.16 Kd373 K
  12. A perfectly black body is one whichaabsorbs all the radiation falling on itbabsorbs only visible lightcreflects all radiationdemits no radiation
  13. A bimetallic strip bends on heating because the two metals have differentadensitiesbspecific heatscthermal conductivitiesdcoefficients of linear expansion
  14. The heat required to raise 100 g of water through 10 °C (specific heat of water = 1 cal g⁻¹ °C⁻¹) isa100 calb1000 calc10,000 cald500 cal
  15. 500 cm³ of a gas is collected at 300 K and 76 cm Hg pressure. Its volume at 600 K and 38 cm Hg will bea250 cm³b1000 cm³c2000 cm³d4000 cm³
  16. According to the second law of thermodynamics, the efficiency of a heat engine can never bea50%b25%c100%d90%
  17. A Carnot engine operates between a source at 127 °C and a sink at 27 °C. Its efficiency isa79%b50%c75%d25%
  18. Sound waves of frequency above the audible range (ultrasonics) have frequencies greater thana20 Hzb2000 Hzc10,000 Hzd20,000 Hz
  19. To hear a distinct echo (persistence of hearing 0.1 s, speed of sound 340 m/s), the reflecting surface must be at least abouta10 m awayb5 m awayc17 m awayd34 m away
  20. An open organ pipe is 0.85 m long. The frequency of its fundamental note (velocity of sound = 340 m/s) isa100 Hzb400 Hzc200 Hzd170 Hz
  21. Short-sightedness (myopia) of the eye is corrected by using spectacle lenses that areaconvexbconcaveccylindricaldbifocal
  22. An object is placed 30 cm in front of a convex lens of focal length 10 cm. The image is formed at a distance ofa7.5 cmb20 cmc30 cmd15 cm
  23. The primary rainbow is produced by dispersion of sunlight combined withainternal reflection inside raindropsbdiffraction at cloud edgescscattering by dust onlydpolarisation in the atmosphere
  24. In Young's double-slit experiment (λ = 500 nm, slits 0.5 mm apart, screen 2 m away), the fringe width isa0.5 mmb1 mmc2 mmd4 mm
  25. Diffraction effects of a wave are most pronounced when the size of the obstacle or aperture isacomparable with the wavelengthbvery much larger than the wavelengthcinfinitedexactly zero
  26. In a balanced Wheatstone bridge, no current flows through the galvanometer when the ratio of resistances satisfiesaP + Q = R + SbPQ = RScP = Q = R = SdP/Q = R/S
  27. An electric heater is marked 60 W at 220 V. The resistance of its heating element is abouta403 Ωb807 Ωc1613 Ωd3.7 Ω
  28. A potentiometer measures the e.m.f. of a cell more accurately than a voltmeter because at the balance point itahas very low resistancebdraws no current from the cellcuses a longer wireddraws a large current
  29. A rectangular coil of 100 turns, area 0.01 m², carrying 2 A, has its plane parallel to a magnetic field of 0.5 T. The torque acting on it isa0.1 N mb0.5 N mc1 N md2 N m
  30. A tangent galvanometer works on the basis of the tangent law, B = B_H tan θ, where B_H is theafield of the coilbtotal fieldcvertical component of Earth's fielddhorizontal component of Earth's field
  31. The magnetic susceptibility of a diamagnetic substance isalarge and positivebsmall and negativecexactly zerodinfinitely large
  32. The energy stored in an inductor of inductance 0.5 H when a current of 2 A flows through it isa1 Jb2 Jc0.5 Jd4 J
  33. The average value of a sinusoidal alternating current over one complete cycle isaequal to its peak valuebzerocequal to its r.m.s. valuedhalf its peak value
  34. Eddy currents in the core of a transformer are minimised by making the coreaof solid ironbof thick copperchollowdlaminated
  35. Two parallel plates 2 cm apart are maintained at a potential difference of 100 V. The force on a charge of 2 μC placed between them isa0.01 Nb0.1 Nc1 Nd0.001 N
  36. If the plate area of a parallel-plate capacitor is doubled (separation unchanged), its capacitance becomesadoublebhalfcfour timesdunchanged
  37. One farad, the unit of capacitance, is equal to oneavolt per coulombbcoulomb per voltcjoule per coulombdampere per second
  38. The work done in moving a charge along an equipotential surface isaalways positivebzerocalways negativedinfinite
  39. Light of wavelength 400 nm falls on a metal of work function 2.0 eV (take hc = 1240 eV·nm). The maximum kinetic energy of the emitted photoelectrons isa1.1 eVb3.1 eVc5.1 eVdzero (no emission)
  40. The threshold (cut-off) frequency for photoelectric emission depends on theaintensity of the lightbtime of exposurecnature (work function) of the metaldarea of the metal surface
  41. The de Broglie wavelength associated with a moving particle is inversely proportional to itsachargebmomentumcfrequency of revolutiondtemperature
  42. The cut-off (minimum) wavelength of X-rays from a tube varies with the accelerating voltage V asaλ ∝ 1/Vbλ ∝ Vcλ ∝ V²dλ independent of V
  43. In the Bohr model, the angular momentum of the electron in the n-th permitted orbit isanhbnh/2πch/2πndany arbitrary value
  44. The mass defect in the formation of a nucleus is 0.05 u (1 u ≡ 931 MeV). The binding energy of the nucleus is abouta46.5 MeVb4.65 MeVc465 MeVd931 MeV
  45. An alpha particle is the nucleus of the elementaheliumbhydrogenclithiumdboron
  46. The energy of the Sun is produced mainly byafission of heavy nucleibfusion of hydrogen nucleicchemical burning of gasesdradioactive decay of uranium
  47. In a transistor, the most heavily doped region is theaemitterbbaseccollectorddepletion layer
  48. The binary (base-2) representation of the decimal number 13 isa1011b1110c1101d1001
  49. The cosmic microwave background radiation is strong evidence in support of theasteady-state theorybtheory of black holes onlycnebular hypothesisdBig Bang theory
  50. The strongest of the four fundamental forces of nature is theastrong nuclear forcebelectromagnetic forcecweak nuclear forcedgravitational force

Mental Agility Test (questions 181–200)

  1. Choose the word nearest in meaning to SCARCE.aPlentifulbRarecCostlydHidden
  2. Choose the word most opposite in meaning to VICTORY.aSuccessbTriumphcConquestdDefeat
  3. Eye : See :: Ear : ?aHearbNoisecDrumdFace
  4. Find the odd one out.aTrianglebSquarecCircledRectangle
  5. A person who speaks many languages is called aamonolingualbpolyglotcoratordbilingual person
  6. Find the next number in the series: 5, 10, 20, 40, ?a50b60c70d80
  7. One-quarter of one-half of 200 isa25b50c100d12.5
  8. Which number is divisible by both 3 and 4?a18b20c27d36
  9. A watch bought for Rs 800 is sold for Rs 920. The profit percentage isa15%b12%c20%d10%
  10. If 3 pens cost Rs 45, the cost of 7 pens of the same kind isaRs 90bRs 105cRs 120dRs 315
  11. Statements: No A is B. Some C are A. Which conclusion follows?aAll C are BbAll C are not BcSome C are not BdNo C is A
  12. Find the next letter in the series: A, C, E, G, ?aHbIcJdK
  13. Hari's brother is the father of Sita. How is Hari related to Sita?aFatherbUnclecGrandfatherdCousin
  14. In a class of 30 students, Ram is 7th from the top. His rank from the bottom isa23rdb25thc22ndd24th
  15. Statement: All mangoes are sweet. This fruit is not sweet. It follows thatathis fruit may still be a mangoball fruits are sweetcnothing followsdthis fruit is not a mango
  16. A square is drawn with both of its diagonals. How many triangles are formed in the figure in total?a4b6c8d10
  17. A clock shows 9:00. In its mirror image, the time appears to bea9:00b6:00c3:00d12:00
  18. You are facing south-east. You turn around through 180°. Which direction do you now face?aNorth-westbSouth-westcNorth-eastdEast
  19. A cube has 6 faces and 12 edges. The number of its vertices (corners) isa6b12c8d4
  20. Which digit looks the same when the page is turned upside down (rotated 180°)?a8b6c9d5

Answer key and explanations

Answers — Zoology (1–40)

1. (a) — de Vries proposed that new species arise by sudden mutations.

2. (d) — Insect and bird wings do the same job from different origins: convergence.

3. (d) — Chance changes in gene frequencies matter most in small populations.

4. (b) — Sponges pump water through a canal system for filter feeding.

5. (a) — Flatworms such as Planaria excrete through flame cells.

6. (d) — Arthropoda is by far the most species-rich phylum.

7. (c) — The ostrich is a flightless running bird.

8. (c) — Areolar tissue is the general loose packing connective tissue.

9. (d) — Haversian canals organise compact mammalian bone.

10. (a) — One thin cell layer lets gases diffuse quickly across alveoli.

11. (a) — Dendrites receive impulses and pass them to the cell body.

12. (c) — Fertilisation and sporogony of Plasmodium occur in the mosquito.

13. (b) — Liver merozoites invade red cells, starting the erythrocytic cycle.

14. (a) — Four pairs of lateral hearts pump blood in segments 7, 9, 12 and 13.

15. (c) — Metanephridia open segmentally to the exterior.

16. (c) — The transparent nictitating membrane covers the eye under water.

17. (b) — Adult amphibians have mesonephric (opisthonephric) kidneys.

18. (a) — Enterokinase later activates trypsinogen to trypsin in the duodenum.

19. (a) — Without bile salts, fats are neither emulsified for lipase nor absorbed well (fatty stools, fat-soluble vitamin deficiency).

20. (b) — About 70% of CO₂ travels as bicarbonate in the plasma.

21. (b) — Vital capacity = TV + IRV + ERV ≈ 4600 mL.

22. (d) — The His–Purkinje system spreads excitation through the ventricles.

23. (a) — Neutrophils are the first-responder phagocytes; their count rises sharply in bacterial infection.

24. (d) — Lymph is plasma-like but without red blood cells.

25. (b) — A long loop builds a steep medullary gradient for very concentrated urine.

26. (b) — Aldosterone promotes Na⁺ (and hence water) reabsorption.

27. (a) — The cerebellum fine-tunes movement and maintains balance.

28. (b) — Rhodopsin in rods serves dim-light vision.

29. (d) — Adrenaline prepares the body for emergency action.

30. (c) — Oxytocin contracts uterine muscle in labour and ejects milk.

31. (c) — The acrosome is a Golgi-derived cap of enzymes.

32. (d) — The mid-cycle LH surge ruptures the mature follicle.

33. (c) — Vibrio cholerae toxin causes the massive watery diarrhoea of cholera.

34. (d) — Interferons warn nearby cells to resist viral multiplication.

35. (c) — Quinine comes from Cinchona bark.

36. (d) — Normal cells stop dividing on contact; cancer cells ignore this control.

37. (b) — The ECG traces the heart's electrical cycle.

38. (d) — Variable tandem repeats differ between individuals, giving a DNA profile.

39. (b) — SO₂ and NOₓ form sulphuric and nitric acids in rain.

40. (c) — In-situ = on site, in the wild habitat; zoos/banks are ex-situ.

Answers — Botany (41–80)

41. (c) — Maltose = glucose + glucose.

42. (b) — Heat denatures the protein: the active site loses its shape, so it no longer binds the substrate even after cooling.

43. (b) — Viruses are obligate intracellular parasites and need living cells.

44. (d) — Lacking mitochondria, bacteria respire across the cell membrane.

45. (a) — Fungal walls are built of chitin.

46. (d) — Agaricus bears basidiospores on gills: a basidiomycete.

47. (d) — The ribbon-like chloroplast spirals through the Spirogyra cell.

48. (b) — Marchantia is a thalloid liverwort.

49. (b) — The heart-shaped prothallus is the fern's gametophyte.

50. (a) — Bladder "wings" help pine pollen float on wind and on the pollination drop.

51. (a) — Pea-family (Fabaceae) flowers have the standard–wings–keel arrangement.

52. (b) — The niche is what the species does, not merely where it lives.

53. (c) — Detritus chains run from dead matter through decomposers and detritivores.

54. (c) — Phosphorus cycles through rocks and sediments, with no large gas phase.

55. (b) — Epiphytes only perch for light; they photosynthesise and take no food from the host.

56. (c) — Cristae carry the respiratory chain of the mitochondrion.

57. (c) — Centromeres split at anaphase and chromatids move poleward.

58. (a) — After the S phase the DNA content is doubled (2C → 4C).

59. (c) — Amyloplasts are starch-storing leucoplasts.

60. (a) — The tonoplast bounds the cell-sap vacuole.

61. (a) — Alleles separate cleanly into gametes: segregation.

62. (d) — Crossing with the homozygous recessive is a test cross.

63. (a) — Meselson and Stahl's density-gradient experiment (1958).

64. (a) — About 147 bp of DNA wrap a histone octamer in each nucleosome.

65. (d) — Ribosomes read mRNA and build the polypeptide.

66. (d) — UAA, UAG and UGA terminate translation.

67. (c) — Companion cells load and sustain the enucleate sieve elements.

68. (d) — Spring and autumn wood from the cambium make the rings.

69. (c) — Lenticels are pores for gas exchange through bark.

70. (d) — At full turgor TP = OP, so DPD = OP − TP = 0.

71. (a) — In a hypertonic medium water leaves the cell and the protoplast shrinks.

72. (d) — Rubisco first yields two molecules of 3-PGA from RuBP + CO₂.

73. (b) — Glycolysis runs in the cytoplasm with or without oxygen.

74. (c) — For glucose CO₂ released = O₂ taken up, so RQ = 1.

75. (c) — Cytokinins are cell-division (cytokinesis) promoters.

76. (b) — Syngamy gives the diploid zygote; triple fusion gives the endosperm.

77. (b) — A true fruit is the ripened ovary (pericarp from its wall).

78. (d) — Taq polymerase from Thermus aquaticus survives the 94 °C step.

79. (b) — Neem seeds yield the insect growth disruptor azadirachtin.

80. (a) — Fusing wall-less protoplasts of the two species made the pomato hybrid cells.

Answers — Chemistry (81–130)

81. (c) — 0.25 × 98 = 24.5 g.

82. (b) — 6.02 × 10²³ particles per mole.

83. (d) — Position and momentum cannot both be known exactly at once.

84. (a) — Deuterium = 1 proton + 1 neutron.

85. (c) — F, Cl, Br, I are the halogens ("salt-formers").

86. (a) — NaCl is an ionic lattice; the others are covalent molecules.

87. (c) — Four equivalent sp³ bonds in tetrahedral methane.

88. (d) — A reducing agent donates electrons and is itself oxidised.

89. (b) — Effusion time ∝ √M: t(O₂) = 20 × √(32/2) = 20 × 4 = 80 s.

90. (b) — (4/40) mol in 0.5 L = 0.2 M.

91. (d) — Weak acid + its conjugate salt resists pH change.

92. (b) — [H⁺] = √(1.8 × 10⁻⁵ × 0.1) ≈ 1.34 × 10⁻³, so pH ≈ 2.87 ≈ 2.9.

93. (b) — The first permanent pink tinge of excess KMnO₄ marks the end point.

94. (d) — Three 10 °C steps: rate × 2³ = 8 (temperature-coefficient rule of thumb).

95. (a) — One faraday deposits one gram-equivalent = 63.5/2 ≈ 31.8 g of Cu.

96. (a) — ΔH = [−393 + 2(−286)] − [−75] = −965 + 75 = −890 kJ/mol.

97. (d) — One quarter = (½)², i.e. two half-lives: 2 × 5730 = 11,460 years.

98. (b) — Dry ice is frozen CO₂, subliming at −78 °C.

99. (d) — SO₂ + H₂O gives nascent hydrogen effects: reductive, temporary bleaching.

100. (c) — 4HNO₃ → 4NO₂ + O₂ + 2H₂O in light; the NO₂ colours it yellow.

101. (a) — Fluorine is the most reactive and electronegative halogen.

102. (c) — CuFeS₂ (chalcopyrite) is copper's main ore.

103. (a) — Sulphide particles are preferentially wetted by oil in froth flotation.

104. (d) — Rust is hydrated iron(III) oxide.

105. (b) — A moving molten zone sweeps impurities out of semiconductor germanium/silicon.

106. (c) — Myoglobin stores oxygen within muscle fibres.

107. (c) — A cobalt atom lies at the heart of the B₁₂ (cobalamin) molecule.

108. (a) — Electrophiles accept an electron pair (e.g. NO₂⁺, carbocations).

109. (c) — Ethyl acetoacetate exists as keto ⇌ enol tautomers.

110. (d) — The phenoxide charge is delocalised into the ring, stabilising it.

111. (a) — DBE = (2C + 2 − H)/2 = (12 + 2 − 10)/2 = 2 (e.g. one ring plus one double bond, or a triple bond).

112. (d) — CH₂=CH₂ cleaves to two molecules of formaldehyde.

113. (b) — FeCl₃ catalyses electrophilic substitution → chlorobenzene.

114. (b) — Ethanol is oxidised to a CH₃CO– unit and gives yellow CHI₃.

115. (a) — Alkoxide + alkyl halide → ether (Williamson).

116. (b) — Zn reduces phenol to benzene on distillation.

117. (d) — Ease of dehydration follows carbocation stability: 3° fastest.

118. (a) — Formalin is ~40% formaldehyde in water.

119. (b) — H₂/Pd–BaSO₄ reduces RCOCl only as far as the aldehyde.

120. (c) — RCOOH + NaHCO₃ → RCOONa + H₂O + CO₂↑.

121. (a) — CH₃COONa + NaOH (soda lime) → CH₄ + Na₂CO₃.

122. (a) — Alkylamines outrank ammonia; both far outrank aniline and amides.

123. (d) — Benzenesulphonyl chloride reacts differently with 1°, 2° and 3° amines.

124. (a) — Picric acid is 2,4,6-trinitrophenol.

125. (c) — Nylons are polyamides (amide linkages along the chain).

126. (c) — Sodium benzoate inhibits microbial spoilage of food.

127. (d) — Lime (CaO) is the largest component of Portland cement.

128. (c) — Sodium gives an intense golden-yellow flame.

129. (b) — Transition-metal ions colour the borax bead characteristically.

130. (b) — In the Carius tube, halogen is precipitated and weighed as AgX.

Answers — Physics (131–180)

131. (d) — R = u² sin 2θ/g = 1600 × sin 60°/10 ≈ 139 m.

132. (c) — 1 hp ≈ 746 W.

133. (d) — Impulse = Ft = 10 N·s = mΔv, so Δv = 10/2 = 5 m/s.

134. (a) — P = mgh/t = 50 × 10 × 10/5 = 1000 W.

135. (d) — Angular momentum is conserved: I₁ω₁ = I₂ω₂, so ω₂ = (6 × 2)/3 = 4 rad/s.

136. (d) — Viscosity's SI unit is the pascal-second.

137. (c) — f = 1/T = 1/0.5 = 2 Hz.

138. (b) — Friction supplies the centripetal force: v = √(μgr) = √(0.4 × 10 × 40) = √160 ≈ 13 m/s.

139. (b) — A near-Earth satellite needs about 7.9 km/s (first cosmic velocity).

140. (c) — Stress = 200/10⁻⁶ = 2 × 10⁸ Pa; strain = stress/Y = 2 × 10⁸/2 × 10¹¹ = 0.001.

141. (c) — The kelvin is defined from the triple point at 273.16 K.

142. (a) — A black body absorbs everything and is the best possible emitter.

143. (d) — Unequal linear expansions curve the strip.

144. (b) — Q = 100 × 1 × 10 = 1000 cal.

145. (c) — V₂ = V₁(T₂/T₁)(P₁/P₂) = 500 × 2 × 2 = 2000 cm³.

146. (c) — No engine converts all heat into work (100% efficiency is impossible).

147. (d) — η = 1 − T₂/T₁ = 1 − 300/400 = 25% (temperatures in kelvin).

148. (d) — Beyond the ~20 kHz limit of hearing lies ultrasound.

149. (c) — Distance = 340 × 0.1/2 = 17 m for a just-distinct echo.

150. (c) — For an open pipe f = v/2L = 340/(2 × 0.85) = 200 Hz.

151. (b) — A diverging (concave) lens corrects myopia.

152. (d) — 1/v = 1/f − 1/u = 1/10 − 1/30 = 1/15, so v = 15 cm (real, inverted).

153. (a) — Refraction disperses the light, which reflects once inside each drop.

154. (c) — β = λD/d = 500 × 10⁻⁹ × 2/(0.5 × 10⁻³) = 2 × 10⁻³ m = 2 mm.

155. (a) — Diffraction is marked when aperture ≈ wavelength.

156. (d) — Balance when P/Q = R/S.

157. (b) — R = V²/P = 220²/60 ≈ 807 Ω.

158. (b) — At null point the cell supplies no current, so true e.m.f. is read.

159. (c) — τ = NIAB (maximum, plane parallel to B) = 100 × 2 × 0.01 × 0.5 = 1 N m.

160. (d) — The needle balances the coil field against Earth's horizontal component.

161. (b) — Diamagnets have small negative susceptibility (weakly repelled).

162. (a) — U = ½LI² = ½ × 0.5 × 4 = 1 J.

163. (b) — Positive and negative halves cancel over a full cycle.

164. (d) — Laminations break up eddy-current paths in the core.

165. (a) — E = V/d = 100/0.02 = 5000 V/m; F = qE = 2 × 10⁻⁶ × 5000 = 0.01 N.

166. (a) — C ∝ A, so capacitance doubles.

167. (b) — 1 F = 1 C/V.

168. (b) — Potential is constant on an equipotential, so no work is done.

169. (a) — Photon energy = 1240/400 = 3.1 eV; K(max) = 3.1 − 2.0 = 1.1 eV.

170. (c) — f₀ = φ/h is fixed by the metal's work function.

171. (b) — λ = h/p: inversely proportional to momentum.

172. (a) — λ(min) = hc/eV (Duane–Hunt law).

173. (b) — Bohr quantised angular momentum as mvr = nh/2π.

174. (a) — BE = Δm × 931 = 0.05 × 931 ≈ 46.5 MeV.

175. (a) — α = ⁴He nucleus (2p + 2n).

176. (b) — Proton–proton fusion powers the Sun.

177. (a) — The emitter is heavily doped to inject many carriers.

178. (c) — 13 = 8 + 4 + 1 = 1101₂.

179. (d) — The 2.7 K background is the cooled remnant of the hot Big Bang.

180. (a) — The strong force binds nuclei and is the most powerful interaction.

Answers — Mental Agility Test (181–200)

181. (b) — Scarce means rare, in short supply.

182. (d) — Defeat is the opposite of victory.

183. (a) — As the eye is for seeing, the ear is for hearing.

184. (c) — The circle has no straight sides or corners.

185. (b) — A polyglot speaks several languages.

186. (d) — Each term doubles: 40 × 2 = 80.

187. (a) — ¼ × ½ × 200 = 25.

188. (d) — 36 = 3 × 12 = 4 × 9.

189. (a) — Profit 120 on 800 is 15%.

190. (b) — One pen costs 15, so 7 cost 105.

191. (c) — Those C that are A cannot be B, so some C are not B.

192. (b) — Odd-position letters: A, C, E, G, I.

193. (b) — The brother of one's father is an uncle.

194. (d) — 30 − 7 + 1 = 24th from the bottom.

195. (d) — A mango would have to be sweet (contrapositive logic).

196. (c) — 4 small corner triangles + 4 half-square triangles = 8.

197. (c) — Mirror time = 12:00 − 9:00 = 3:00.

198. (a) — Opposite of south-east is north-west.

199. (c) — A cube has 8 corners (Euler: 6 − 12 + 8 = 2).

200. (a) — 8 rotated 180° remains 8 (6 and 9 swap into each other).