JEE Main 2024 — 4 Apr Shift 2 (Previous Year Paper)

JEE Main · 2024 · with answers and explanations

questions
86
Total marks
284
Duration
180 minutes
Negative marking
−1

Subjects: Physics · Chemistry · Mathematics

Question 1

Physics · 4 marks · −1

Applying the principle of homogeneity of dimensions, determine which one is correct, where T is time period, G is gravitational constant, M is mass, r is radius of orbit.

  1. A.T2=4π2r2GMT^2=\frac{4\pi^2r^2}{GM}
  2. B.T2=4π2rGM2T^2=\frac{4\pi^2r}{GM^2}
  3. C.T2=4π2r3GMT^2=\frac{4\pi^2r^3}{GM}
  4. D.T2=4π2r3T^2=4\pi^2r^3

Correct answer: C

Question 2

Physics · 4 marks · −1

A cyclist starts from the point P of a circular ground of radius 2 km and travels along its circumference to the point S. The displacement of a cyclist is:

Figure for question 2
  1. A.8\sqrt8 km
  2. B.8 km
  3. C.6 km
  4. D.4 km

Correct answer: A

Explanation: Displacement is the chord PS =22=2\sqrt2 km.

Question 3

Physics · 4 marks · −1

A 2 kg brick begins to slide over a surface which is inclined at an angle of 45° with respect to horizontal axis. The co-efficient of static friction between their surfaces is:

  1. A.1.7
  2. B.13\frac1{\sqrt3}
  3. C.0.5
  4. D.1

Correct answer: D

Question 4

Physics · 4 marks · −1

A body of m kg slides from rest along the curve of vertical circle from point A to B in friction less path. The velocity of the body at B is: (given, R = 14 m, g = 10 m/s² and 2=1.4\sqrt2=1.4)

Figure for question 4
  1. A.16.7 m/s
  2. B.19.8 m/s
  3. C.10.6 m/s
  4. D.21.9 m/s

Correct answer: D

Explanation: Drop =R(1+sin⁡45∘)=23.8=R(1+\sin45^\circ)=23.8 m; v=2gh≈21.9v=\sqrt{2gh}\approx21.9 m/s.

Question 5

Physics · 4 marks · −1

A 90 kg body placed at 2R distance from surface of earth experiences gravitational pull of: (R = Radius of earth, g = 10 m s−2^{-2})

  1. A.100 N
  2. B.300 N
  3. C.225 N
  4. D.120 N

Correct answer: A

Explanation: Distance from centre 3R: 9009=100\frac{900}{9}=100 N.

Question 6

Physics · 4 marks · −1

Correct formula for height of a satellite from earths surface is:

  1. A.(T2R24π2g)1/3−R\left(\frac{T^2R^2}{4\pi^2g}\right)^{1/3}-R
  2. B.(T2R2g4π2)1/3−R\left(\frac{T^2R^2g}{4\pi^2}\right)^{1/3}-R
  3. C.(T2R2g4π2)−1/3+R\left(\frac{T^2R^2g}{4\pi^2}\right)^{-1/3}+R
  4. D.(T2R2g4π)1/2−R\left(\frac{T^2R^2g}{4\pi}\right)^{1/2}-R

Correct answer: B

Question 7

Physics · 4 marks · −1

Given below are two statements : Statement I : The contact angle between a solid and a liquid is a property of the material of the solid and liquid as well. Statement II : The rise of a liquid in a capillary tube does not depend on the inner radius of the tube. In the light of the above statements, choose the correct answer from the options given below:

  1. A.Statement I is true but Statement II is false.
  2. B.Statement I is false but Statement II is true.
  3. C.Both Statement I and Statement II are false.
  4. D.Both Statement I and Statement II are true.

Correct answer: A

Question 8

Physics · 4 marks · −1

A sample of gas at temperature T is adiabatically expanded to double its volume. Adiabatic constant for the gas is γ = 3/2. The work done by the gas in the process is: (μ = 1 mole)

  1. A.RT[1−22]RT[1-2\sqrt2]
  2. B.RT[2−2]RT[\sqrt2-2]
  3. C.RT[2−2]RT[2-\sqrt2]
  4. D.RT[22−1]RT[2\sqrt2-1]

Correct answer: C

Explanation: T2=T/2T_2=T/\sqrt2; W=R(T−T2)γ−1=RT(2−2)W=\frac{R(T-T_2)}{\gamma-1}=RT(2-\sqrt2).

Question 9

Physics · 4 marks · −1

The translational degrees of freedom (ft)(f_t) and rotational degrees of freedom (fr)(f_r) of CH4\text{CH}_4 molecule are:

  1. A.ft=2f_t=2 and fr=2f_r=2
  2. B.ft=3f_t=3 and fr=3f_r=3
  3. C.ft=3f_t=3 and fr=2f_r=2
  4. D.ft=2f_t=2 and fr=3f_r=3

Correct answer: B

Question 10

Physics · 4 marks · −1

A charge q is placed at the center of one of the surface of a cube. The flux linked with the cube is:

  1. A.q2ϵ0\frac{q}{2\epsilon_0}
  2. B.q8ϵ0\frac{q}{8\epsilon_0}
  3. C.Zero
  4. D.q4ϵ0\frac{q}{4\epsilon_0}

Correct answer: A

Question 11

Physics · 4 marks · −1

An electric bulb rated 50 W – 200 V is connected across a 100 V supply. The power dissipation of the bulb is:

  1. A.25 W
  2. B.12.5 W
  3. C.50 W
  4. D.100 W

Correct answer: B

Explanation: P∝V2P\propto V^2: 50/450/4.

Question 12

Physics · 4 marks · −1

The magnetic moment of a bar magnet is 0.5 A m². It is suspended in a uniform magnetic field of 8×10−28\times10^{-2} T. The work done in rotating it from its most stable to most unstable position is:

  1. A.8×10−28\times10^{-2} J
  2. B.4×10−24\times10^{-2} J
  3. C.Zero
  4. D.16×10−216\times10^{-2} J

Correct answer: A

Explanation: W=2MBW=2MB.

Question 13

Physics · 4 marks · −1

Match List I with List II List I: A. Purely capacitive circuit; B. Purely inductive circuit; C. LCR series at resonance; D. LCR series circuit List II: I. phasor diagram with I vertical and V horizontal (90° between them, I leading); II. I and V along the same line; III. V making angle θ with I; IV. phasor diagram with V vertical and I horizontal (90°, V leading) Choose the correct answer from the options given below:

Figure for question 13
  1. A.A-I, B-IV, C-II, D-III
  2. B.A-IV, B-I, C-II, D-III
  3. C.A-IV, B-I, C-III, D-II
  4. D.A-I, B-IV, C-III, D-II

Correct answer: A

Question 14

Physics · 4 marks · −1

Arrange the following in the ascending order of wavelength: A. Gamma rays (λ1)(\lambda_1) B. x - rays (λ2)(\lambda_2) C. Infrared waves (λ3)(\lambda_3) D. Microwaves (λ4)(\lambda_4) Choose the most appropriate answer from the options given below

  1. A.λ4<λ3<λ1<λ2\lambda_4<\lambda_3<\lambda_1<\lambda_2
  2. B.λ2<λ1<λ4<λ3\lambda_2<\lambda_1<\lambda_4<\lambda_3
  3. C.λ1<λ2<λ3<λ4\lambda_1<\lambda_2<\lambda_3<\lambda_4
  4. D.λ4<λ3<λ2<λ1\lambda_4<\lambda_3<\lambda_2<\lambda_1

Correct answer: C

Question 15

Physics · 4 marks · −1

The width of one of the two slits in a Young's double slit experiment is 4 times that of the other slit. The ratio of the maximum of the minimum intensity in the interference pattern is:

  1. A.1 : 1
  2. B.4 : 1
  3. C.9 : 1
  4. D.16 : 1

Correct answer: C

Explanation: Amplitudes 2 : 1 ⇒ (2+1)2(2−1)2\frac{(2+1)^2}{(2-1)^2}.

Question 16

Physics · 4 marks · −1

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Number of photons increases with increase in frequency of light. Reason R: Maximum kinetic energy of emitted electrons increases with the frequency of incident radiation. In the light of the above statements, choose the most appropriate answer from the options given below:

  1. A.Both A and R are correct and R is the correct explanation of A.
  2. B.Both A and R are correct and R is NOT the correct explanation of A.
  3. C.A is not correct but R is correct.
  4. D.A is correct but R is not correct.

Correct answer: C

Question 17

Physics · 4 marks · −1

According to Bohr's theory, the moment of momentum of an electron revolving in 4th4^{th} orbit of hydrogen atom is:

  1. A.hπ\frac h\pi
  2. B.h2π\frac{h}{2\pi}
  3. C.8hπ8\frac h\pi
  4. D.2hπ2\frac h\pi

Correct answer: D

Question 18

Physics · 4 marks · −1

Identify the logic gate given in the circuit:

Figure for question 18
  1. A.NAND-gate
  2. B.AND gate
  3. C.NOR gate
  4. D.OR- gate

Correct answer: D

Explanation: Aˉ⋅Bˉ‾=A+B\overline{\bar A\cdot\bar B}=A+B.

Question 19

Physics · 4 marks · −1

A bus moving along a straight highway with speed of 72 km/h is brought to halt within 4s after applying the brakes. The distance travelled by the bus during this time (Assume the retardation is uniform) is ______ m.

Correct answer: 40

Explanation: 202×4=40\frac{20}{2}\times4=40 m.

Question 20

Physics · 4 marks · −1

In a system two particles of masses m1=3m_1=3 kg and m2=2m_2=2 kg are placed at certain distance from each other. The particle of mass m1m_1 is moved towards the center of mass of the system through a distance 2 cm. In order to keep the center of mass of the system at the original position, the particle of mass m2m_2 should move towards the center of mass by the distance ______ cm.

Correct answer: 3

Explanation: 3×2=2×d3\times2=2\times d.

Question 21

Physics · 4 marks · −1

Mercury is filled in a tube of radius 2 cm up to a height of 30 cm. The force exerted by mercury on the bottom of the tube is ______ N. (Given, atmospheric pressure = 10510^5 N m−2^{-2}, density of mercury = 1.36×1041.36\times10^4 kg m−3^{-3}, g = 10 m s−2^{-2}, π=227\pi=\frac{22}{7})

Correct answer: 177

Explanation: (105+1.36×104×10×0.3)×π(0.02)2≈177(10^5+1.36\times10^4\times10\times0.3)\times\pi(0.02)^2\approx177 N.

Question 22

Physics · 4 marks · −1

The displacement of a particle executing SHM is given by x=10sin⁡(ωt+π3)x=10\sin\left(\omega t+\frac\pi3\right) m. The time period of motion is 3.14 s. The velocity of the particle at t = 0 is ______ m/s.

Correct answer: 10

Explanation: ω=2\omega=2; v=10×2cos⁡π3=10v=10\times2\cos\frac\pi3=10.

Question 23

Physics · 4 marks · −1

A parallel plate capacitor of capacitance 12.5 pF is charged by a battery connected between its plates to potential difference of 12.0 V. The battery is now disconnected and a dielectric slab (ϵr=6)(\epsilon_r=6) is inserted between the plates. The change in its potential energy after inserting the dielectric slab is ______ ×10−12\times10^{-12} J.

Correct answer: 750

Explanation: U=900U=900 pJ falls to 150150 pJ: change 750.

Question 24

Physics · 4 marks · −1

Two wires A and B are made up of the same material and have the same mass. Wire A has radius of 2.0 mm and wire B has radius of 4.0 mm. The resistance of wire B is 2Ω. The resistance of wire A is ______ Ω.

Correct answer: 32

Explanation: Same volume: R∝1r4R\propto\frac1{r^4}; 2×16=322\times16=32.

Question 25

Physics · 4 marks · −1

Two parallel long current carrying wire separated by a distance 2r are shown in the figure. The ratio of magnetic field at A to the magnetic field produced at C is x7\frac x7. The value of x is ______.

Figure for question 25

Correct answer: 5

Explanation: BA∝Ir+2I3r=5I3rB_A\propto\frac Ir+\frac{2I}{3r}=\frac{5I}{3r}, BC∝I3r+2Ir=7I3rB_C\propto\frac{I}{3r}+\frac{2I}{r}=\frac{7I}{3r}.

Question 26

Physics · 4 marks · −1

A rod of length 60 cm rotates with a uniform angular velocity 20 rad s−1^{-1} about its perpendicular bisector, in a uniform magnetic filed 0.5 T. The direction of magnetic field is parallel to the axis of rotation. The potential difference between the two ends of the rod is ______ V.

Correct answer: 0

Explanation: Both halves develop equal emf from the centre outward, so the ends are at the same potential.

Question 27

Physics · 4 marks · −1

A light ray is incident on a glass slab of thickness 434\sqrt3 cm and refractive index 2\sqrt2. The angle of incidence is equal to the critical angle for the glass slab with air. The lateral displacement of ray after passing through glass slab is ______ cm. (Given sin 15° = 0.25)

Correct answer: 2

Explanation: i=45∘i=45^\circ, r=30∘r=30^\circ; d=tsin⁡(i−r)cos⁡r=43×0.253/2=2d=\frac{t\sin(i-r)}{\cos r}=\frac{4\sqrt3\times0.25}{\sqrt3/2}=2 cm.

Question 28

Physics · 4 marks · −1

The disintegration energy Q for the nuclear fission of 235U→140Ce+94Zr+n{}^{235}\text{U}\to{}^{140}\text{Ce}+{}^{94}\text{Zr}+n is ______ MeV. Given atomic masses of 235{}^{235}U : 235.0439 u; 140{}^{140}Ce : 139.9054 u, 94{}^{94}Zr : 93.9063 u; n : 1.0086 u, Value of c2=931c^2=931 MeV/u

Correct answer: 208

Explanation: Δm=0.2236\Delta m=0.2236 u → 208 MeV.

Question 29

Chemistry · 4 marks · −1

The correct order of the first ionization enthalpy is

  1. A.Al > Ga > Tl
  2. B.Ga > Al > B
  3. C.Tl > Ga > Al
  4. D.B > Al > Ga

Correct answer: C

Explanation: Tl (589) > Ga (579) > Al (577) kJ/mol.

Question 30

Chemistry · 4 marks · −1

Given below are two statements : Statement I : The correct order of first ionization enthalpy values of Li, Na, F and Cl is Na < Li < Cl < F. Statement II : The correct order of negative electron gain enthalpy values of Li, Na, F and Cl is Na < Li < F < Cl. In the light of the above statements, choose the correct answer from the options given below :

  1. A.Statement I is true but Statement II is false
  2. B.Statement I is false but Statement II is true
  3. C.Both Statement I and Statement II are false
  4. D.Both Statement I and Statement II are true

Correct answer: D

Question 31

Chemistry · 4 marks · −1

The correct statement/s about Hydrogen bonding is/are A. Hydrogen bonding exists when H is covalently bonded to the highly electro negative atom. B. Intermolecular H bonding is present in o-nitro phenol C. Intramolecular H bonding is present in HF. D. The magnitude of H bonding depends on the physical state of the compound. E. H-bonding has powerful effect on the structure and properties of compounds Choose the correct answer from the options given below:

  1. A.A, B, D only
  2. B.A, D, E only
  3. C.A only
  4. D.A, B, C only

Correct answer: B

Question 32

Chemistry · 4 marks · −1

The number of species from the following that have pyramidal geometry around the central atom is ______. S2O32−\text{S}_2\text{O}_3^{2-}, SO42−\text{SO}_4^{2-}, SO32−\text{SO}_3^{2-}, S2O72−\text{S}_2\text{O}_7^{2-}

  1. A.4
  2. B.3
  3. C.2
  4. D.1

Correct answer: D

Explanation: Only sulphite.

Question 33

Chemistry · 4 marks · −1

The equilibrium constant for the reaction SO3(g)⇌SO2(g)+12O2(g)\text{SO}_3(g)\rightleftharpoons\text{SO}_2(g)+\frac12\text{O}_2(g) is Kc=4.9×10−2K_c=4.9\times10^{-2}. The value of KcK_c for the reaction given below is 2SO2(g)+O2(g)⇌2SO3(g)2\text{SO}_2(g)+\text{O}_2(g)\rightleftharpoons2\text{SO}_3(g) is :

  1. A.4.9
  2. B.49
  3. C.41.6
  4. D.416

Correct answer: D

Explanation: 1(0.049)2≈416\frac{1}{(0.049)^2}\approx416.

Question 34

Chemistry · 4 marks · −1

Correct order of stability of carbanion is - (a) cyclopropenyl anion (b) cyclobutyl anion (c) cyclopentenyl (allylic) anion (d) cyclopentadienyl anion

Figure for question 34
  1. A.d > a > c > b
  2. B.a > b > c > d
  3. C.d > c > b > a
  4. D.c > b > d > a

Correct answer: C

Explanation: Aromatic (d) > allylic (c) > simple (b) > antiaromatic (a).

Question 35

Chemistry · 4 marks · −1

Common name of Benzene - 1, 2 - diol is -

  1. A.catechol
  2. B.o-cresol
  3. C.quinol
  4. D.resorcinol

Correct answer: A

Question 36

Chemistry · 4 marks · −1

The adsorbent used in adsorption chromatography is/are - A. silica gel B. alumina C. quick lime D. magnesia Choose the most appropriate answer from the options given below :

  1. A.A only
  2. B.B only
  3. C.C and D only
  4. D.A and B only

Correct answer: D

Question 37

Chemistry · 4 marks · −1

(2-Bromo-3-methylbutyl)benzene, C6H5CH2-CHBr-CH(CH3)2\text{C}_6\text{H}_5\text{CH}_2\text{-CHBr-CH(CH}_3)_2 →KOH(alc), Δ\xrightarrow{\text{KOH(alc)},\ \Delta} major product "P". Product P is

Figure for question 37
  1. A.C6H5CH2CH2C(CH3)=CH2\text{C}_6\text{H}_5\text{CH}_2\text{CH}_2\text{C(CH}_3\text{)=CH}_2
  2. B.C6H5C(=CH2)CH(CH3)2\text{C}_6\text{H}_5\text{C(=CH}_2\text{)CH(CH}_3)_2
  3. C.C6H5CH=CH-CH(CH3)2\text{C}_6\text{H}_5\text{CH=CH-CH(CH}_3)_2
  4. D.C6H5CH2CH=C(CH3)2\text{C}_6\text{H}_5\text{CH}_2\text{CH=C(CH}_3)_2

Correct answer: C

Explanation: The conjugated (styrene-type) alkene is the most stable elimination product.

Question 38

Chemistry · 4 marks · −1

1-Methylcyclohexene →"A"\xrightarrow{\text{"A"}} 6-oxoheptanal →"B"\xrightarrow{\text{"B"}} sodium 5-formylpentanoate. In the above chemical reaction sequence "A" and "B" respectively are

Figure for question 38
  1. A.H2O\text{H}_2\text{O}, H+\text{H}^+ and KMnO4\text{KMnO}_4
  2. B.O3\text{O}_3, Zn/H2O\text{H}_2\text{O} and NaOH(alc)\text{NaOH}_{(alc)}/I2\text{I}_2
  3. C.O3\text{O}_3, Zn/H2O\text{H}_2\text{O} and KMnO4\text{KMnO}_4
  4. D.H2O\text{H}_2\text{O}, H+\text{H}^+ and NaOH(alc)\text{NaOH}_{(alc)}/I2\text{I}_2

Correct answer: B

Explanation: Reductive ozonolysis cleaves the ring; the iodoform reaction converts the methyl ketone to a carboxylate.

Question 39

Chemistry · 4 marks · −1

For a strong electrolyte, a plot of molar conductivity against (concentration)1/2^{1/2} is a straight line, with a negative slope, the correct unit for the slope is

  1. A.S cm² mol−3/2^{-3/2} L−1/2^{-1/2}
  2. B.S cm² mol−3/2^{-3/2} L1/2^{1/2}
  3. C.S cm² mol−3/2^{-3/2} L
  4. D.S cm² mol−1^{-1} L1/2^{1/2}

Correct answer: B

Question 40

Chemistry · 4 marks · −1

Fuel cell, using hydrogen and oxygen as fuels, A. has been used in spaceship B. has as efficiency of 40% to produce electricity C. uses aluminum as catalysts D. is eco-friendry E. is actually a type of Galvanic cell only. Choose the correct answer from the options given below:

  1. A.A, B, D, E only
  2. B.A, D, E only
  3. C.A, B, D only
  4. D.A, B, C only

Correct answer: B

Question 41

Chemistry · 4 marks · −1

When MnO2\text{MnO}_2 and H2SO4\text{H}_2\text{SO}_4 is added to a salt (A), the greenish yellow gas liberated as salt (A) is :

  1. A.CaI2\text{CaI}_2
  2. B.NaBr
  3. C.KNO3\text{KNO}_3
  4. D.NH4Cl\text{NH}_4\text{Cl}

Correct answer: D

Question 42

Chemistry · 4 marks · −1

A first row transition metal in its +2 oxidation state has a spin-only magnetic moment value of 3.86 BM. The atomic number of the metal is

  1. A.26
  2. B.25
  3. C.23
  4. D.22

Correct answer: C

Explanation: Three unpaired electrons as M2+^{2+} ⇒ d3^3 ⇒ V.

Question 43

Chemistry · 4 marks · −1

If an iron (III) complex with the formula [Fe(NH3)x(CN)y]−[\text{Fe(NH}_3)_x(\text{CN})_y]^- has no electron in its ege_g orbital, then the value of x + y is

  1. A.4
  2. B.5
  3. C.6
  4. D.3

Correct answer: C

Explanation: Low-spin octahedral Fe(III): x+y=6x+y=6 (with y=4y=4 for charge −1).

Question 44

Chemistry · 4 marks · −1

The number of unpaired d-electrons in [Co(H2O)6]3+[\text{Co(H}_2\text{O)}_6]^{3+} is

  1. A.2
  2. B.1
  3. C.0
  4. D.4

Correct answer: C

Question 45

Chemistry · 4 marks · −1

CH3-CH2-CH2-Br+NaOH→C2H5OH\text{CH}_3\text{-CH}_2\text{-CH}_2\text{-Br}+\text{NaOH}\xrightarrow{\text{C}_2\text{H}_5\text{OH}} Product 'A'; Product A →H2O/H+\xrightarrow{\text{H}_2\text{O}/\text{H}^+} Product "B"; Product A →Diborane, H2O/H2O2/O−H\xrightarrow{\text{Diborane},\ \text{H}_2\text{O}/\text{H}_2\text{O}_2/\overset{-}{\text{O}}\text{H}} Product "C". Consider the above reactions, identify product B and product C.

  1. A.B = 1-Propanol C = 2-Propanol
  2. B.B = C = 2-Propanol
  3. C.B = 2-Propanol C = 1-Propanol
  4. D.B = C = 1-Propanol

Correct answer: C

Question 46

Chemistry · 4 marks · −1

Match List I with List II List - I: A. α - Glucose and α - Galactose; B. α - Glucose and β - Glucose; C. α - Glucose and α - Fructose; D. α - Glucose and α - Ribose List - II: I. Functional isomers; II. Homologous; III. Anomers; IV. Epimers Choose the correct answer from the options given below:

  1. A.A-IV, B-III, C-I, D-II
  2. B.A-III, B-IV, C-I, D-II
  3. C.A-IV, B-III, C-II, D-I
  4. D.A-III, B-IV, C-II, D-I

Correct answer: A

Question 47

Chemistry · 4 marks · −1

The maximum number of orbitals which can be identified with n = 4 and ml=0m_l=0 is ______

Correct answer: 4

Explanation: One for each l=0,1,2,3l=0,1,2,3.

Question 48

Chemistry · 4 marks · −1

Number of compounds / species from the following with non-zero dipole moment is ______ BeCl2\text{BeCl}_2, BCl3\text{BCl}_3, NF3\text{NF}_3, XeF4\text{XeF}_4, CCl4\text{CCl}_4, H2O\text{H}_2\text{O}, H2S\text{H}_2\text{S}, HBr, CO2\text{CO}_2, H2\text{H}_2, HCl

Correct answer: 5

Explanation: NF3_3, H2_2O, H2_2S, HBr, HCl.

Question 49

Chemistry · 4 marks · −1

Three moles of an ideal gas are compressed isothermally from 60 L to 20 L using constant pressure of 5 atm. Heat exchange Q for the compression is - ______ Lit. atm.

Correct answer: 200

Explanation: w=−5(20−60)=200w=-5(20-60)=200 L atm; Q=−200Q=-200 L atm.

Question 50

Chemistry · 4 marks · −1

The total number of 'sigma' and 'Pi' bonds in 2-oxohex-4-ynoic acid is ______

Correct answer: 18

Explanation: HOOC-CO-CH2-C≡C-CH3\text{HOOC-CO-CH}_2\text{-C}\equiv\text{C-CH}_3: 14 σ + 4 π.

Question 51

Chemistry · 4 marks · −1

2.7 kg of each of water and acetic acid are mixed. The freezing point of the solution will be −x-x°C. Consider the acetic acid does not dimerise in water, nor dissociates in water. x = ______ (nearest integer) [Given: Molar mass of water = 18 g mol−1^{-1}, acetic acid = 60 g mol−1^{-1}, KfK_f H2O\text{H}_2\text{O} : 1.86 K kg mol−1^{-1}, KfK_f acetic acid : 3.90 K kg mol−1^{-1}, freezing point : H2O\text{H}_2\text{O} = 273 K, acetic acid = 290 K]

Correct answer: 31

Explanation: Water (150 mol) is the solvent: m=452.7=16.7m=\frac{45}{2.7}=16.7; ΔTf=31\Delta T_f=31 K.

Question 52

Chemistry · 4 marks · −1

Consider the following reaction, the rate expression of which is given below A+B→CA+B\to C, rate =k[A]1/2[B]1/2=k[A]^{1/2}[B]^{1/2}. The reaction is initiated by taking 1M concentration of A and B each. If the rate constant (k) is 4.6×10−24.6\times10^{-2} s−1^{-1}, then the time taken for A to become 0.1M is ______ sec. (nearest integer)

Correct answer: 50

Explanation: With [A]=[B][A]=[B] the rate is k[A]k[A]: t=2.3030.046=50t=\frac{2.303}{0.046}=50 s.

Question 53

Chemistry · 4 marks · −1

A first row transition metal with highest enthalpy of atomisation, upon reaction with oxygen at high temperature forms oxides of formula M2On\text{M}_2\text{O}_n (where n = 3, 4, 5). The 'spin-only' magnetic moment value of the amphoteric oxide from the above oxides is ______ BM (near integer) (Given atomic number: Sc : 21, Ti : 22, V : 23, Cr : 24, Mn : 25, Fe : 26, Co : 27, Ni : 28, Cu : 29, Zn : 30)

Correct answer: 0

Explanation: Vanadium; amphoteric V2_2O5_5 is d0^0.

Question 54

Chemistry · 4 marks · −1

Phthalimide is made to undergo following sequence of reactions. Phthalimide →(i) KOH (ii) Benzylchloride\xrightarrow{\text{(i) KOH (ii) Benzylchloride}} 'P'. Total number of π bonds present in product 'P' is/are ______

Correct answer: 8

Explanation: N-benzylphthalimide: 3 + 3 aromatic + 2 C=O.

Question 55

Chemistry · 4 marks · −1

From 6.55 g of aniline, the maximum amount of acetanilide that can be prepared will be ______ ×10−1\times10^{-1} g.

Correct answer: 95

Explanation: 6.5593×135=9.5\frac{6.55}{93}\times135=9.5 g.

Question 56

Chemistry · 4 marks · −1

Vanillin compound obtained from vanilla beans, has total sum of oxygen atoms and π electrons is ______

Correct answer: 11

Explanation: 3 O atoms + 8 π electrons.

Question 57

Mathematics · 4 marks · −1

The area (in sq. units) of the region S={z∈C:∣z−1∣≤2; (z+zˉ)+i(z−zˉ)≤2, Im(z)≥0}S=\{z\in\mathbb{C}:|z-1|\le2;\ (z+\bar z)+i(z-\bar z)\le2,\ \text{Im}(z)\ge0\} is

  1. A.7π3\frac{7\pi}{3}
  2. B.7π4\frac{7\pi}{4}
  3. C.17π8\frac{17\pi}{8}
  4. D.3π2\frac{3\pi}{2}

Correct answer: D

Explanation: x−y≤1x-y\le1 is the region above a line through the centre at 45°; with y≥0y\ge0 it is a 135° sector of radius 2.

Question 58

Mathematics · 4 marks · −1

The value of 1×22+2×32+…+100×(101)212×2+22×3+…+1002×101\frac{1\times2^2+2\times3^2+\ldots+100\times(101)^2}{1^2\times2+2^2\times3+\ldots+100^2\times101} is

  1. A.3231\frac{32}{31}
  2. B.3130\frac{31}{30}
  3. C.306305\frac{306}{305}
  4. D.305301\frac{305}{301}

Correct answer: D

Explanation: Numerator ∑(k3+2k2+k)=26184250\sum(k^3+2k^2+k)=26184250, denominator ∑(k3+k2)=25840850\sum(k^3+k^2)=25840850; ratio 305301\frac{305}{301}.

Question 59

Mathematics · 4 marks · −1

Let three real numbers a, b, c be in arithmetic progression and a + 1, b, c + 3 be in geometric progression. If a > 10 and the arithmetic mean of a, b and c is 8, then the cube of the geometric mean of a, b and c is

  1. A.128
  2. B.316
  3. C.120
  4. D.312

Correct answer: C

Explanation: b=8b=8, (9−d)(11+d)=64⇒d=−7(9-d)(11+d)=64\Rightarrow d=-7: a,b,c=15,8,1a,b,c=15,8,1; abc=120abc=120.

Question 60

Mathematics · 4 marks · −1

If the coefficients of x4x^4, x5x^5 and x6x^6 in the expansion of (1+x)n(1+x)^n are in the arithmetic progression, then the maximum value of n is:

  1. A.7
  2. B.21
  3. C.28
  4. D.14

Correct answer: D

Explanation: n2−21n+98=0⇒n=7,14n^2-21n+98=0\Rightarrow n=7,14.

Question 61

Mathematics · 4 marks · −1

Let C be a circle with radius 10\sqrt{10} units and centre at the origin. Let the line x + y = 2 intersects the circle C at the points P and Q. Let MN be a chord of C of length 2 unit and slope −1. Then, a distance (in units) between the chord PQ and the chord MN is

  1. A.3−23-\sqrt2
  2. B.2+1\sqrt2+1
  3. C.2−1\sqrt2-1
  4. D.2−32-\sqrt3

Correct answer: A

Explanation: PQ is 2\sqrt2 from the centre, MN is 3 from it (same side).

Question 62

Mathematics · 4 marks · −1

Let PQ be a chord of the parabola y2=12xy^2=12x and the midpoint of PQ be at (4, 1). Then, which of the following point lies on the line passing through the points P and Q?

  1. A.(3, −3)
  2. B.(2, −9)
  3. C.(32,−16)\left(\frac32,-16\right)
  4. D.(12,−20)\left(\frac12,-20\right)

Correct answer: D

Explanation: T=S1T=S_1: y=6x−23y=6x-23.

Question 63

Mathematics · 4 marks · −1

Consider a hyperbola H having centre at the origin and foci on the x-axis. Let C1C_1 be the circle touching the hyperbola H and having the centre at the origin. Let C2C_2 be the circle touching the hyperbola H at its vertex and having the centre at one of its foci. If areas (in sq units) of C1C_1 and C2C_2 are 36π and 4π, respectively, then the length (in units) of latus rectum of H is

  1. A.143\frac{14}{3}
  2. B.283\frac{28}{3}
  3. C.113\frac{11}{3}
  4. D.103\frac{10}{3}

Correct answer: B

Explanation: a=6a=6, c−a=2c-a=2, b2=28b^2=28; 2b2a=283\frac{2b^2}{a}=\frac{28}{3}.

Question 64

Mathematics · 4 marks · −1

Let f(x)=∫0x(t+sin⁡(1−et))dtf(x)=\int_0^x\left(t+\sin(1-e^t)\right)dt, x∈Rx\in\mathbb{R}. Then, lim⁡x→0f(x)x3\lim_{x\to0}\frac{f(x)}{x^3} is equal to

  1. A.−16-\frac16
  2. B.23\frac23
  3. C.−23-\frac23
  4. D.16\frac16

Correct answer: A

Explanation: Integrand ≈−t22\approx-\frac{t^2}{2}, so f(x)≈−x36f(x)\approx-\frac{x^3}{6}.

Question 65

Mathematics · 4 marks · −1

If the mean of the following probability distribution of a random variable X: | X | 0 | 2 | 4 | 6 | 8 | | P(X) | a | 2a | a + b | 2b | 3b | is 469\frac{46}{9}, then the variance of the distribution is

  1. A.17327\frac{173}{27}
  2. B.56681\frac{566}{81}
  3. C.15127\frac{151}{27}
  4. D.58181\frac{581}{81}

Correct answer: B

Explanation: a=112a=\frac1{12}, b=19b=\frac19; E(X2)=2989E(X^2)=\frac{298}{9}; variance 56681\frac{566}{81}.

Question 66

Mathematics · 4 marks · −1

Let a relation R on N × N be defined as: (x1,y1)R(x2,y2)(x_1,y_1)R(x_2,y_2) if and only if x1≤x2x_1\le x_2 or y1≤y2y_1\le y_2. Consider the two statements: (I) R is reflexive but not symmetric. (II) R is transitive Then which one of the following is true?

  1. A.Both (I) and (II) are correct.
  2. B.Only (II) is correct.
  3. C.Neither (I) nor (II) is correct.
  4. D.Only (I) is correct.

Correct answer: D

Explanation: (5,5)R(1,6)(5,5)R(1,6) and (1,6)R(4,1)(1,6)R(4,1) but not (5,5)R(4,1)(5,5)R(4,1).

Question 67

Mathematics · 4 marks · −1

Let A=[1201]A=\begin{bmatrix}1&2\\0&1\end{bmatrix} and B=I+adj(A)+(adjA)2+…+(adjA)10B=I+\text{adj}(A)+(\text{adj}A)^2+\ldots+(\text{adj}A)^{10}. Then, the sum of all the elements of the matrix B is:

  1. A.−124
  2. B.22
  3. C.−88
  4. D.−110

Correct answer: C

Explanation: (adjA)k=[1−2k01](\text{adj}A)^k=\begin{bmatrix}1&-2k\\0&1\end{bmatrix}; B=[11−110011]B=\begin{bmatrix}11&-110\\0&11\end{bmatrix}.

Question 68

Mathematics · 4 marks · −1

Given that the inverse trigonometric function assumes principal values only. Let x, y be any two real numbers in [−1, 1] such that cos⁡−1x−sin⁡−1y=α\cos^{-1}x-\sin^{-1}y=\alpha, −π2≤α≤π-\frac\pi2\le\alpha\le\pi. Then, the minimum value of x2+y2+2xysin⁡αx^2+y^2+2xy\sin\alpha is

  1. A.0
  2. B.−1
  3. C.12\frac12
  4. D.−12-\frac12

Correct answer: A

Explanation: With x=cos⁡θx=\cos\theta, y=sin⁡ϕy=\sin\phi, α=θ−ϕ\alpha=\theta-\phi, the expression equals cos⁡2α≥0\cos^2\alpha\ge0, and 0 is attained.

Question 69

Mathematics · 4 marks · −1

If the function f(x)={72x−9x−8x+12−1+cos⁡x,x≠0alog⁡e2log⁡e3,x=0f(x)=\begin{cases}\frac{72^x-9^x-8^x+1}{\sqrt2-\sqrt{1+\cos x}}, & x\ne0\\ a\log_e2\log_e3, & x=0\end{cases} is continuous at x = 0, then the value of a2a^2 is equal to

  1. A.968
  2. B.1152
  3. C.746
  4. D.1250

Correct answer: B

Explanation: Numerator (9x−1)(8x−1)≈6x2ln⁡2ln⁡3(9^x-1)(8^x-1)\approx6x^2\ln2\ln3, denominator ≈2x28\approx\frac{\sqrt2x^2}{8}: limit 242ln⁡2ln⁡324\sqrt2\ln2\ln3.

Question 70

Mathematics · 4 marks · −1

Let f(x)=3x−2+4−xf(x)=3\sqrt{x-2}+\sqrt{4-x} be a real valued function. If α and β are respectively the minimum and the maximum values of f, then α2+2β2\alpha^2+2\beta^2 is equal to

  1. A.42
  2. B.38
  3. C.24
  4. D.44

Correct answer: A

Explanation: β2=10×2=20\beta^2=10\times2=20 (Cauchy–Schwarz); α=f(2)=2\alpha=f(2)=\sqrt2.

Question 71

Mathematics · 4 marks · −1

If the value of the integral ∫−11cos⁡αx1+3xdx\int_{-1}^{1}\frac{\cos\alpha x}{1+3^x}dx is 2π\frac2\pi. Then, a value of α is

  1. A.π3\frac\pi3
  2. B.π6\frac\pi6
  3. C.π4\frac\pi4
  4. D.π2\frac\pi2

Correct answer: D

Explanation: The integral equals ∫01cos⁡αx dx=sin⁡αα\int_0^1\cos\alpha x\,dx=\frac{\sin\alpha}{\alpha}.

Question 72

Mathematics · 4 marks · −1

The area (in sq. units) of the region described by {(x,y):y2≤2x, and y≥4x−1}\{(x,y):y^2\le2x,\text{ and }y\ge4x-1\} is

  1. A.1132\frac{11}{32}
  2. B.89\frac89
  3. C.1112\frac{11}{12}
  4. D.932\frac9{32}

Correct answer: D

Explanation: ∫−1/21(y+14−y22)dy=932\int_{-1/2}^{1}\left(\frac{y+1}{4}-\frac{y^2}{2}\right)dy=\frac9{32}.

Question 73

Mathematics · 4 marks · −1

Let y = y(x) be the solution of the differential equation (x2+4)2dy+(2x3y+8xy−2)dx=0(x^2+4)^2dy+(2x^3y+8xy-2)dx=0. If y(0) = 0, then y(2) is equal to

  1. A.π32\frac\pi{32}
  2. B.2π2\pi
  3. C.π8\frac\pi8
  4. D.π16\frac\pi{16}

Correct answer: A

Explanation: ddx[y(x2+4)]=2x2+4\frac{d}{dx}[y(x^2+4)]=\frac{2}{x^2+4} gives y(x2+4)=tan⁡−1x2y(x^2+4)=\tan^{-1}\frac x2.

Question 74

Mathematics · 4 marks · −1

Let a⃗=i^+j^+k^\vec a=\hat i+\hat j+\hat k, b⃗=2i^+4j^−5k^\vec b=2\hat i+4\hat j-5\hat k and c⃗=xi^+2j^+3k^\vec c=x\hat i+2\hat j+3\hat k, x∈Rx\in\mathbb{R}. If d⃗\vec d is the unit vector in the direction of b⃗+c⃗\vec b+\vec c such that a⃗⋅d⃗=1\vec a\cdot\vec d=1, then (a⃗×b⃗)⋅c⃗(\vec a\times\vec b)\cdot\vec c is equal to

  1. A.11
  2. B.3
  3. C.9
  4. D.6

Correct answer: A

Explanation: (x+6)2=(x+2)2+40⇒x=1(x+6)^2=(x+2)^2+40\Rightarrow x=1; the triple product is 11.

Question 75

Mathematics · 4 marks · −1

For λ > 0, let θ be the angle between the vectors a⃗=i^+λj^−3k^\vec a=\hat i+\lambda\hat j-3\hat k and b⃗=3i^−j^+2k^\vec b=3\hat i-\hat j+2\hat k. If the vectors a⃗+b⃗\vec a+\vec b and a⃗−b⃗\vec a-\vec b are mutually perpendicular, then the value of (14cos⁡θ)2(14\cos\theta)^2 is equal to

  1. A.50
  2. B.40
  3. C.25
  4. D.20

Correct answer: C

Explanation: ∣a⃗∣=∣b⃗∣⇒λ=2|\vec a|=|\vec b|\Rightarrow\lambda=2; cos⁡θ=−514\cos\theta=-\frac5{14}.

Question 76

Mathematics · 4 marks · −1

Let P be the point of intersection of the lines x−21=y−45=z−21\frac{x-2}{1}=\frac{y-4}{5}=\frac{z-2}{1} and x−32=y−23=z−32\frac{x-3}{2}=\frac{y-2}{3}=\frac{z-3}{2}. Then, the shortest distance of P from the line 4x = 2y = z is

  1. A.5147\frac{5\sqrt{14}}{7}
  2. B.3147\frac{3\sqrt{14}}{7}
  3. C.147\frac{\sqrt{14}}{7}
  4. D.6147\frac{6\sqrt{14}}{7}

Correct answer: B

Explanation: P=(1,−1,1)P=(1,-1,1); distance2^2 from the line with direction (1, 2, 4) is 3−37=1873-\frac37=\frac{18}{7}.

Question 77

Mathematics · 4 marks · −1

There are 4 men and 5 women in Group A, and 5 men and 4 women in Group B. If 4 persons are selected from each group, then the number of ways of selecting 4 men and 4 women is ______

Correct answer: 5626

Explanation: 25+1600+3600+400+1=562625+1600+3600+400+1=5626.

Question 78

Mathematics · 4 marks · −1

Let S={sin⁡22θ:(sin⁡4θ+cos⁡4θ)x2+(sin⁡2θ)x+(sin⁡6θ+cos⁡6θ)=0S=\{\sin^22\theta:(\sin^4\theta+\cos^4\theta)x^2+(\sin2\theta)x+(\sin^6\theta+\cos^6\theta)=0 has real roots}\}. If α and β be the smallest and largest elements of the set S, respectively, then 3((α−2)2+(β−1)2)3((\alpha-2)^2+(\beta-1)^2) equals ______

Correct answer: 4

Question 79

Mathematics · 4 marks · −1

Consider a triangle ABC having the vertices A(1, 2), B(α, β) and C(γ, δ) and angles ∠ABC=π6\angle ABC=\frac\pi6 and ∠BAC=2π3\angle BAC=\frac{2\pi}{3}. If the points B and C lie on the line y = x + 4, then α2+γ2\alpha^2+\gamma^2 is equal to ______

Correct answer: 14

Question 80

Mathematics · 4 marks · −1

Let A be a 2 × 2 symmetric matrix such that A[11]=[37]A\begin{bmatrix}1\\1\end{bmatrix}=\begin{bmatrix}3\\7\end{bmatrix} and the determinant of A be 1. If A−1=αA+βIA^{-1}=\alpha A+\beta I, where I is an identity matrix of order 2 × 2, then α + β equals ______

Correct answer: 5

Question 81

Mathematics · 4 marks · −1

Consider the function f:R→Rf:\mathbb{R}\to\mathbb{R} defined by f(x)=2x1+9x2f(x)=\frac{2x}{\sqrt{1+9x^2}}. If the composition of f, (f∘f∘⋯∘f)⏟10 times(x)=210x1+9αx2\underbrace{(f\circ f\circ\cdots\circ f)}_{10\text{ times}}(x)=\frac{2^{10}x}{\sqrt{1+9\alpha x^2}}, then the value of 3α+1\sqrt{3\alpha+1} is equal to ______

Correct answer: 1024

Explanation: f(n)(x)=2nx1+9(1+4+…+4n−1)x2f^{(n)}(x)=\frac{2^nx}{\sqrt{1+9(1+4+\ldots+4^{n-1})x^2}}: α=410−13\alpha=\frac{4^{10}-1}{3}, 3α+1=210\sqrt{3\alpha+1}=2^{10}.

Question 82

Mathematics · 4 marks · −1

Let f:R→Rf:\mathbb{R}\to\mathbb{R} be a thrice differentiable function such that f(0) = 0, f(1) = 1, f(2) = −1, f(3) = 2 and f(4) = −2. Then, the minimum number of zeros of (3f′f′′+ff′′′)(x)(3f'f''+ff''')(x) is ______

Correct answer: 5

Question 83

Mathematics · 4 marks · −1

If ∫cosec⁡5x dx=αcot⁡xcosec⁡x(cosec⁡2x+32)+βlog⁡e∣tan⁡x2∣+C\int\operatorname{cosec}^5x\,dx=\alpha\cot x\operatorname{cosec}x\left(\operatorname{cosec}^2x+\frac32\right)+\beta\log_e\left|\tan\frac x2\right|+C where α, β ∈ R and C is the constant of integration, then the value of 8(α + β) equals ______

Correct answer: 1

Explanation: Reduction formula: α=−14\alpha=-\frac14, β=38\beta=\frac38; 8(α+β)=18(\alpha+\beta)=1.

Question 84

Mathematics · 4 marks · −1

Let y = y(x) be the solution of the differential equation (x+y+2)2dx=dy(x+y+2)^2dx=dy, y(0) = −2. Let the maximum and minimum values of the function y = y(x) in [0,π3]\left[0,\frac\pi3\right] be α and β, respectively. If (3α+π)2+β2=γ+δ3(3\alpha+\pi)^2+\beta^2=\gamma+\delta\sqrt3, γ, δ ∈ Z, then γ + δ equals ______

Correct answer: 31

Explanation: y=tan⁡x−x−2y=\tan x-x-2 (increasing): α=3−π3−2\alpha=\sqrt3-\frac\pi3-2, β=−2\beta=-2; (33−6)2+4=67−363(3\sqrt3-6)^2+4=67-36\sqrt3.

Question 85

Mathematics · 4 marks · −1

Consider a line L passing through the points P(1, 2, 1) and Q(2, 1, −1). If the mirror image of the point A(2, 2, 2) in the line L is (α, β, γ), then α + β + 6γ is equal to ______

Correct answer: 6

Explanation: Foot (56,136,43)\left(\frac56,\frac{13}{6},\frac43\right); image (−13,73,23)\left(-\frac13,\frac73,\frac23\right).

Question 86

Mathematics · 4 marks · −1

In a tournament, a team plays 10 matches with probabilities of winning and losing each match as 13\frac13 and 23\frac23 respectively. Let x be the number of matches that the team wins, and y be the number of matches that team loses. If the probability P(∣x−y∣≤2)P(|x-y|\le2) is p, then 39p3^9p equals ______

Correct answer: 8288

Explanation: x∈{4,5,6}x\in\{4,5,6\}: 210⋅64+252⋅32+210⋅163=8288\frac{210\cdot64+252\cdot32+210\cdot16}{3}=8288.

View all papers — JEE Main

Practice this paper with a timer

Attempt it online, get scored instantly, and see which subjects are costing you marks.

Start practising free