JEE Main 2025 — 29 Jan Shift 2 (Previous Year Paper)

JEE Main · 2025 · with answers and explanations

questions
73
Total marks
292
Duration
180 minutes
Negative marking
−1

Subjects: Mathematics · Physics · Chemistry

Question 1

Mathematics · 4 marks · −1

Let the line x + y = 1 meet the axes of x and y at A and B, respectively. A right angled triangle AMN is inscribed in the triangle OAB, where O is the origin and the points M and N lie on the lines OB and AB, respectively. If the area of the triangle AMN is 49\frac{4}{9} of the area of the triangle OAB and AN : NB = λ : 1, then the sum of all possible value(s) of λ is :

  1. A.136\frac{13}{6}
  2. B.52\frac{5}{2}
  3. C.12\frac{1}{2}
  4. D.2

Correct answer: D

Question 2

Mathematics · 4 marks · −1

Let A=[aij]A=[a_{ij}] be a 2×2 matrix such that aij∈{0,1}a_{ij}\in\{0, 1\} for all i and j. Let the random variable X denote the possible values of the determinant of the matrix A. Then, the variance of X is :

  1. A.14\frac{1}{4}
  2. B.58\frac{5}{8}
  3. C.34\frac{3}{4}
  4. D.38\frac{3}{8}

Correct answer: D

Explanation: Of 16 matrices: det = 1 in 3, −1 in 3, 0 in 10; E = 0, E(X2)=616=38E(X^2)=\frac{6}{16}=\frac38.

Question 3

Mathematics · 4 marks · −1

Let a straight line L pass through the point P(2, −1, 3) and be perpendicular to the lines x−12=y+11=z−3−2\frac{x-1}{2}=\frac{y+1}{1}=\frac{z-3}{-2} and x−31=y−23=z+24\frac{x-3}{1}=\frac{y-2}{3}=\frac{z+2}{4}. If the line L intersects the yz-plane at the point Q, then the distance between the points P and Q is :

  1. A.10\sqrt{10}
  2. B.232\sqrt{3}
  3. C.2
  4. D.3

Correct answer: D

Explanation: Direction (2,1,−2)×(1,3,4)=(10,−10,5)∝(2,−2,1)(2,1,-2)\times(1,3,4)=(10,-10,5)\propto(2,-2,1); x = 0 at t = −1: Q = (0, 1, 2); PQ = 3.

Question 4

Mathematics · 4 marks · −1

If for the solution curve y = f(x) of the differential equation dydx+(tan⁡x)y=2+sec⁡x(1+2sec⁡x)2\frac{dy}{dx}+(\tan x)y=\frac{2+\sec x}{(1+2\sec x)^2}, x∈(−π2,π2)x\in\left(-\frac{\pi}{2}, \frac{\pi}{2}\right), f(π3)=310f\left(\frac{\pi}{3}\right)=\frac{\sqrt{3}}{10}, then f(π4)f\left(\frac{\pi}{4}\right) is equal to :

  1. A.93+310(4+3)\frac{9\sqrt{3}+3}{10(4+\sqrt{3})}
  2. B.4−214\frac{4-\sqrt{2}}{14}
  3. C.5−322\frac{5-\sqrt{3}}{2\sqrt{2}}
  4. D.3+110(4+3)\frac{\sqrt{3}+1}{10(4+\sqrt{3})}

Correct answer: B

Question 5

Mathematics · 4 marks · −1

Let α, β (α ≠ β) be the values of m, for which the equations x + y + z = 1; x + 2y + 4z = m and x+4y+10z=m2x+4y+10z=m^2 have infinitely many solutions. Then the value of ∑n=110(nα+nβ)\sum_{n=1}^{10}(n^\alpha+n^\beta) is equal to :

  1. A.560
  2. B.3080
  3. C.3410
  4. D.440

Correct answer: D

Explanation: Determinant is 0; consistency: m2−3m+2=0m^2-3m+2=0 ⇒ m = 1, 2; ∑n+∑n2=55+385=440\sum n+\sum n^2=55+385=440.

Question 6

Mathematics · 4 marks · −1

Let the area enclosed between the curves ∣y∣=1−x2|y|=1-x^2 and x2+y2=1x^2+y^2=1 be α. If 9α = βπ + γ; β, γ are integers, then the value of |β − γ| equals.

  1. A.27
  2. B.18
  3. C.33
  4. D.15

Correct answer: C

Explanation: Circle area π minus region inside ∣y∣≤1−x2|y|\le1-x^2 (area 8/3): α=π−83\alpha=\pi-\frac83; 9α=9π−249\alpha=9\pi-24; |9 + 24| = 33.

Question 7

Mathematics · 4 marks · −1

If all the words with or without meaning made using all the letters of the word "KANPUR" are arranged as in a dictionary, then the word at 440th position in this arrangement, is :

  1. A.PRKAUN
  2. B.PRNAUK
  3. C.PRKANU
  4. D.PRNAKU

Correct answer: A

Question 8

Mathematics · 4 marks · −1

If the set of all a ∈ R, for which the equation 2x2+(a−5)x+15=3a2x^2+(a-5)x+15=3a has no real root, is the interval (α, β), and X = {x ∈ Z : α < x < β}, then ∑x∈Xx2\sum_{x\in X}x^2 is equal to :

  1. A.2109
  2. B.2119
  3. C.2129
  4. D.2139

Correct answer: D

Explanation: (a−5)2<8(15−3a)(a-5)^2<8(15-3a) ⇒ a2+14a−95<0a^2+14a-95<0 ⇒ −19<a<5-19<a<5: ∑−184x2=2109\sum_{-18}^{4}x^2=2109.

Question 9

Mathematics · 4 marks · −1

If the domain of the function log⁡5(18x−x2−77)\log_5(18x-x^2-77) is (α, β) and the domain of the function log⁡(x−1)(2x2+3x−2x2−3x−4)\log_{(x-1)}\left(\frac{2x^2+3x-2}{x^2-3x-4}\right) is (γ, δ), then α2+β2+γ2\alpha^2+\beta^2+\gamma^2 is equal to :

  1. A.186
  2. B.174
  3. C.179
  4. D.195

Correct answer: A

Question 10

Mathematics · 4 marks · −1

Let a circle C pass through the points (4, 2) and (0, 2), and its centre lie on 3x + 2y + 2 = 0. Then the length of the chord, of the circle C, whose mid-point is (1, 2), is :

  1. A.424\sqrt{2}
  2. B.232\sqrt{3}
  3. C.222\sqrt{2}
  4. D.3\sqrt{3}

Correct answer: B

Explanation: Centre on x = 2: (2, −4), r2=40r^2=40; distance to (1, 2) is 37\sqrt{37}: chord 232\sqrt{3}.

Question 11

Mathematics · 4 marks · −1

Bag 1 contains 4 white balls and 5 black balls, and Bag 2 contains n white balls and 3 black balls. One ball is drawn randomly from Bag 1 and transferred to Bag 2. A ball is then drawn randomly from Bag 2. If the probability, that the ball drawn is white, is 29/45, then n is equal to :

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

Correct answer: A

Explanation: 4(n+1)+5n9(n+4)=2945\frac{4(n+1)+5n}{9(n+4)}=\frac{29}{45} ⇒ n = 6.

Question 12

Mathematics · 4 marks · −1

Let A=[aij]A=[a_{ij}] be a matrix of order 3×3, with aij=(2)i+ja_{ij}=(\sqrt{2})^{i+j}. If the sum of all the elements in the third row of A2A^2 is α+β2\alpha+\beta\sqrt{2}, α, β ∈ Z, then α + β is equal to :

  1. A.210
  2. B.168
  3. C.224
  4. D.280

Correct answer: C

Question 13

Mathematics · 4 marks · −1

If sin⁡x+sin⁡2x=1\sin x+\sin^2x=1, x∈(0,π2)x\in\left(0, \frac{\pi}{2}\right), then (cos⁡12x+tan⁡12x)+3(cos⁡10x+tan⁡10x+cos⁡8x+tan⁡8x)+(cos⁡6x+tan⁡6x)(\cos^{12}x+\tan^{12}x)+3(\cos^{10}x+\tan^{10}x+\cos^8x+\tan^8x)+(\cos^6x+\tan^6x) is equal to :

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

Correct answer: B

Explanation: cos⁡2x=sin⁡x\cos^2x=\sin x and tan⁡2x=cos⁡2x\tan^2x=\cos^2x, so each bracket pairs terms of (c+c2)3(c+c^2)^3-type expansions with c=cos⁡2xc=\cos^2x satisfying c+c2=1c+c^2=1; the whole expression equals 2(c+c2)3=22(c+c^2)^3=2.

Question 14

Mathematics · 4 marks · −1

If αx + βy = 109 is the equation of the chord of the ellipse x29+y24=1\frac{x^2}{9}+\frac{y^2}{4}=1, whose mid point is (52,12)\left(\frac{5}{2}, \frac{1}{2}\right), then α + β is equal to :

  1. A.58
  2. B.72
  3. C.46
  4. D.37

Correct answer: A

Explanation: 5x18+y8=2536+116=109144\frac{5x}{18}+\frac{y}{8}=\frac{25}{36}+\frac{1}{16}=\frac{109}{144} ⇒ 40x+18y=10940x+18y=109: 58.

Question 15

Mathematics · 4 marks · −1

Let S = N ∪ {0}. Define a relation R from S to R by : R={(x,y):log⁡ey=xlog⁡e(25),x∈S,y∈R}R=\left\{(x, y): \log_ey=x\log_e\left(\frac{2}{5}\right), x\in S, y\in\mathbf{R}\right\}. Then, the sum of all the elements in the range of R is equal to :

  1. A.109\frac{10}{9}
  2. B.52\frac{5}{2}
  3. C.53\frac{5}{3}
  4. D.32\frac{3}{2}

Correct answer: C

Explanation: y=(2/5)xy=(2/5)^x: sum 11−2/5=53\frac{1}{1-2/5}=\frac53.

Question 16

Mathematics · 4 marks · −1

Let f(x)=∫0xt(t2−9t+20)dtf(x)=\int_0^xt(t^2-9t+20)dt, 1 ≤ x ≤ 5. If the range of f is [α, β], then 4(α + β) equals :

  1. A.154
  2. B.125
  3. C.253
  4. D.157

Correct answer: D

Question 17

Mathematics · 4 marks · −1

Let P be the foot of the perpendicular from the point (1, 2, 2) on the line L: x−11=y+1−1=z−22\frac{x-1}{1}=\frac{y+1}{-1}=\frac{z-2}{2}. Let the line r⃗=(−i^+j^−2k^)+λ(i^−j^+k^)\vec{r}=(-\hat{i}+\hat{j}-2\hat{k})+\lambda(\hat{i}-\hat{j}+\hat{k}), λ ∈ R, intersect the line L at Q. Then 2(PQ)22(PQ)^2 is equal to :

  1. A.19
  2. B.25
  3. C.27
  4. D.29

Correct answer: C

Question 18

Mathematics · 4 marks · −1

Let a^\hat{a} be a unit vector perpendicular to the vectors b⃗=i^−2j^+3k^\vec{b}=\hat{i}-2\hat{j}+3\hat{k} and c⃗=2i^+3j^−k^\vec{c}=2\hat{i}+3\hat{j}-\hat{k}, and makes an angle of cos⁡−1(−13)\cos^{-1}\left(-\frac{1}{3}\right) with the vector i^+j^+k^\hat{i}+\hat{j}+\hat{k}. If a^\hat{a} makes an angle of π3\frac{\pi}{3} with the vector i^+αj^+k^\hat{i}+\alpha\hat{j}+\hat{k}, then the value of α is :

  1. A.6\sqrt{6}
  2. B.−3-\sqrt{3}
  3. C.−6-\sqrt{6}
  4. D.3\sqrt{3}

Correct answer: C

Explanation: b⃗×c⃗=(−7,7,7)\vec b\times\vec c=(-7,7,7) ⇒ a^=±13(−1,1,1)\hat a=\pm\frac{1}{\sqrt3}(-1,1,1); angle with (1,1,1) gives a^=13(1,−1,−1)\hat a=\frac{1}{\sqrt3}(1,-1,-1); −α32+α2=12\frac{-\alpha}{\sqrt3\sqrt{2+\alpha^2}}=\frac12 ⇒ α=−6\alpha=-\sqrt6.

Question 19

Mathematics · 4 marks · −1

The remainder, when 71037^{103} is divided by 23, is equal to :

  1. A.6
  2. B.14
  3. C.17
  4. D.9

Correct answer: B

Explanation: 722≡17^{22}\equiv1 (mod 23): 7103≡7157^{103}\equiv7^{15}; computing gives 14.

Question 20

Mathematics · 4 marks · −1

Let integers a, b ∈ [−3, 3] be such that a + b ≠ 0. Then the number of all possible ordered pairs (a, b), for which ∣z−az+b∣=1\left|\frac{z-a}{z+b}\right|=1 and ∣z+1ωω2ωz+ω21ω21z+ω∣=1\begin{vmatrix}z+1 & \omega & \omega^2\\ \omega & z+\omega^2 & 1\\ \omega^2 & 1 & z+\omega\end{vmatrix}=1, z ∈ C, where ω and ω2\omega^2 are the roots of x2+x+1=0x^2+x+1=0, is equal to ______.

Correct answer: 10

Explanation: The determinant equals z3=1z^3=1, so z ∈ {1, ω, ω²}; ∣z−a∣=∣z+b∣|z-a|=|z+b| requires z to lie on the perpendicular bisector of a and −b (the line Re z = (a−b)/2). Counting admissible integer pairs (a, b) ∈ [−3, 3]² with a + b ≠ 0 gives 10.

Question 21

Mathematics · 4 marks · −1

If lim⁡t→0(∫01(3x+5)tdx)1t=α5e(85)23\lim_{t\to0}\left(\int_0^1(3x+5)^tdx\right)^{\frac{1}{t}}=\frac{\alpha}{5e}\left(\frac{8}{5}\right)^{\frac{2}{3}}, then α is equal to ______.

Correct answer: 64

Question 22

Mathematics · 4 marks · −1

If 24∫0π/4(sin⁡∣4x−π12∣+[2sin⁡x])dx=2π+α24\int_0^{\pi/4}\left(\sin\left|4x-\frac{\pi}{12}\right|+[2\sin x]\right)dx=2\pi+\alpha, where [·] denotes the greatest integer function, then α is equal to ______.

Correct answer: 12

Question 23

Mathematics · 4 marks · −1

Let y2=12xy^2=12x be the parabola and S be its focus. Let PQ be a focal chord of the parabola such that (SP)(SQ)=1474(SP)(SQ)=\frac{147}{4}. Let C be the circle described taking PQ as a diameter. If the equation of a circle C is 64x2+64y2−αx−643y=β64x^2+64y^2-\alpha x-64\sqrt{3}y=\beta, then β − α is equal to ______.

Correct answer: 1328

Question 24

Mathematics · 4 marks · −1

Let a1,a2,…,a2024a_1, a_2, \ldots, a_{2024} be an Arithmetic Progression such that a1+(a5+a10+a15+…+a2020)+a2024=2233a_1+(a_5+a_{10}+a_{15}+\ldots+a_{2020})+a_{2024}=2233. Then a1+a2+a3+…+a2024a_1+a_2+a_3+\ldots+a_{2024} is equal to ______.

Correct answer: 11132

Explanation: 404 middle terms pair up to 202(a1+a2024)202(a_1+a_{2024}); total 203(a1+a2024)=2233203(a_1+a_{2024})=2233 ⇒ a1+a2024=11a_1+a_{2024}=11; sum =1012×11=11132=1012\times11=11132.

Question 25

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) : Three identical spheres A, B, C of same mass undergo one dimensional motion as shown in figure with initial velocities vAv_A = 5 m/s, vBv_B = 2 m/s, vCv_C = 4 m/s. If we wait sufficiently long for elastic collision to happen, then vAv_A = 4 m/s, vBv_B = 2 m/s, vCv_C = 5 m/s will be the final velocities. Reason (R) : In an elastic collision between identical masses, two objects exchange their velocities. In the light of the above statements, choose the correct answer from the options given below :

Figure for question 25
  1. A.(A) is true but (R) is false
  2. B.Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
  3. C.Both (A) and (R) are true and (R) is the correct explanation of (A)
  4. D.(A) is false but (R) is true

Correct answer: D

Explanation: B–C: C is ahead and faster, so they never meet first; A hits B (5↔2), then B (now 5) hits C (4): exchanges → final A 2, B 4, C 5. So A is false, R is true.

Question 26

Physics · 4 marks · −1

A convex lens made of glass (refractive index = 1.5) has focal length 24 cm in air. When it is totally immersed in water (refractive index = 1.33), its focal length changes to

  1. A.48 cm
  2. B.96 cm
  3. C.24 cm
  4. D.72 cm

Correct answer: B

Explanation: fwfa=0.51.5/1.33−1≈4\frac{f_w}{f_a}=\frac{0.5}{1.5/1.33-1}\approx4: 96 cm.

Question 27

Physics · 4 marks · −1

A sand dropper drops sand of mass m(t) on a conveyer belt at a rate proportional to the square root of speed (v) of the belt, i.e. dmdt∝v\frac{dm}{dt}\propto\sqrt{v}. If P is the power delivered to run the belt at constant speed then which of the following relationship is true ?

  1. A.P ∝ v
  2. B.P2∝v3P^2\propto v^3
  3. C.P ∝ v\sqrt{v}
  4. D.P2∝v5P^2\propto v^5

Correct answer: D

Explanation: F=vdmdt∝v3/2F=v\frac{dm}{dt}\propto v^{3/2}, P=Fv∝v5/2P=Fv\propto v^{5/2}.

Question 28

Physics · 4 marks · −1

A cup of coffee cools from 90°C to 80°C in t minutes when the room temperature is 20°C. The time taken by the similar cup of coffee to cool from 80°C to 60°C at the same room temperature is :

  1. A.135t\frac{13}{5}t
  2. B.1013t\frac{10}{13}t
  3. C.513t\frac{5}{13}t
  4. D.1310t\frac{13}{10}t

Correct answer: A

Explanation: Average-temperature form: 10t=k(65)\frac{10}{t}=k(65), \frac{20}{t\'}=k(50) ⇒ t=ˊ135tt\'=\frac{13}{5}t.

Question 29

Physics · 4 marks · −1

The difference of temperature in a material can convert heat energy into electrical energy. To harvest the heat energy, the material should have

  1. A.low thermal conductivity and high electrical conductivity
  2. B.high thermal conductivity and low electrical conductivity
  3. C.low thermal conductivity and low electrical conductivity
  4. D.high thermal conductivity and high electrical conductivity

Correct answer: A

Question 30

Physics · 4 marks · −1

Two concave refracting surfaces of equal radii of curvature and refractive index 1.5 face each other in air as shown in figure. A point object O is placed midway, between P and B. The separation between the images of O, formed by each refracting surface is :

Figure for question 30
  1. A.0.114R
  2. B.0.124R
  3. C.0.411R
  4. D.0.214R

Correct answer: A

Explanation: Each concave surface forms a virtual image of O; the separation of the two images is 0.114R per the NTA key.

Question 31

Physics · 4 marks · −1

Match List - I with List - II. List - I: (A) Young's Modulus (B) Torque (C) Coefficient of Viscosity (D) Gravitational Constant. List - II: (I) ML−1T−1ML^{-1}T^{-1} (II) ML−1T−2ML^{-1}T^{-2} (III) M−1L3T−2M^{-1}L^3T^{-2} (IV) ML2T−2ML^2T^{-2}. Choose the correct answer from the options given below :

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

Correct answer: A

Question 32

Physics · 4 marks · −1

In an experiment with photoelectric effect, the stopping potential,

  1. A.increases with increase in the wavelength of the incident light
  2. B.is (1e)\left(\frac{1}{e}\right) times the maximum kinetic energy of the emitted photoelectrons
  3. C.decreases with increase in the intensity of the incident light
  4. D.increases with increase in the intensity of the incident light

Correct answer: B

Question 33

Physics · 4 marks · −1

An electric dipole is placed at a distance of 2 cm from an infinite plane sheet having positive charge density σ0\sigma_0. Choose the correct option from the following.

Figure for question 33
  1. A.Potential energy and torque both are maximum.
  2. B.Potential energy of dipole is minimum and torque is zero.
  3. C.Torque on dipole is zero and net force is directed away from the sheet.
  4. D.Torque on dipole is zero and net force acts towards the sheet.

Correct answer: B

Explanation: Dipole aligned with the uniform field: torque zero, force zero, PE minimum.

Question 34

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) : With the increase in the pressure of an ideal gas, the volume falls off more rapidly in an isothermal process in comparison to the adiabatic process. Reason (R) : In isothermal process, PV = constant, while in adiabatic process PVγPV^\gamma = constant. Here γ is the ratio of specific heats, P is the pressure and V is the volume of the ideal gas. In the light of the above statements, choose the correct answer from the options given below :

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

Correct answer: B

Question 35

Physics · 4 marks · −1

A capacitor, C1C_1 = 6 μF is charged to a potential difference of V0V_0 = 5V using a 5V battery. The battery is removed and another capacitor, C2C_2 = 12 μF is inserted in place of the battery. When the switch 'S' is closed, the charge flows between the capacitors for some time until equilibrium condition is reached. What are the charges (q1q_1 and q2q_2) on the capacitors C1C_1 and C2C_2 when equilibrium condition is reached.

  1. A.q1q_1 = 10 μC, q2q_2 = 20 μC
  2. B.q1q_1 = 30 μC, q2q_2 = 15 μC
  3. C.q1q_1 = 20 μC, q2q_2 = 10 μC
  4. D.q1q_1 = 15 μC, q2q_2 = 30 μC

Correct answer: A

Explanation: Q = 30 μC shared at common V = 30/18 V: 10 and 20 μC.

Question 36

Physics · 4 marks · −1

The number of spectral lines emitted by atomic hydrogen that is in the 4th4^{th} energy level, is

  1. A.0
  2. B.1
  3. C.3
  4. D.6

Correct answer: D

Explanation: (42)=6\binom42=6.

Question 37

Physics · 4 marks · −1

A point charge causes an electric flux of −2×104-2\times10^4 Nm2C−1m^2C^{-1} to pass through a spherical Gaussian surface of 8.0 cm radius, centred on the charge. The value of the point charge is : (Given ϵ0=8.85×10−12 C2N−1m−2\epsilon_0=8.85\times10^{-12}\ C^2N^{-1}m^{-2})

  1. A.−15.7×10−8-15.7\times10^{-8} C
  2. B.17.7×10−817.7\times10^{-8} C
  3. C.−17.7×10−8-17.7\times10^{-8} C
  4. D.15.7×10−815.7\times10^{-8} C

Correct answer: C

Explanation: q=ϵ0ϕ=−1.77×10−7q=\epsilon_0\phi=-1.77\times10^{-7} C.

Question 38

Physics · 4 marks · −1

A poly-atomic molecule (CVC_V = 3R, CPC_P = 4R, where R is gas constant) goes from phase space point A(PA=105P_A=10^5 Pa, VA=4×10−6V_A=4\times10^{-6} m³) to point B(PB=5×104P_B=5\times10^4 Pa, VB=6×10−6V_B=6\times10^{-6} m³) to point C(PC=104P_C=10^4 Pa, VC=8×10−6V_C=8\times10^{-6} m³). A to B is an adiabatic path and B to C is an isothermal path. The net heat absorbed per unit mole by the system is :

Figure for question 38
  1. A.450R(ln4 − ln3)
  2. B.400R ln4
  3. C.500R(ln3 + ln4)
  4. D.500R ln2

Correct answer: A

Explanation: Only B→C absorbs heat: Q=RTln⁡VCVB=450Rln⁡43Q=RT\ln\frac{V_C}{V_B}=450R\ln\frac43.

Question 39

Physics · 4 marks · −1

Two identical symmetric double convex lenses of focal length f are cut into two equal parts L1L_1, L2L_2 by AB plane and L3L_3, L4L_4 by XY plane as shown in figure respectively. The ratio of focal lengths of lenses L1L_1 and L3L_3 is

Figure for question 39
  1. A.2 : 1
  2. B.1 : 2
  3. C.1 : 1
  4. D.1 : 4

Correct answer: B

Explanation: L1L_1 has focal length f; L3L_3 (plano-convex) has 2f: 1 : 2.

Question 40

Physics · 4 marks · −1

Two bodies A and B of equal mass are suspended from two massless springs of spring constant k1k_1 and k2k_2, respectively. If the bodies oscillate vertically such that their amplitudes are equal, the ratio of the maximum velocity of A to the maximum velocity of B is

  1. A.k2k1\sqrt{\frac{k_2}{k_1}}
  2. B.k1k2\sqrt{\frac{k_1}{k_2}}
  3. C.k1k2\frac{k_1}{k_2}
  4. D.k2k1\frac{k_2}{k_1}

Correct answer: B

Question 41

Physics · 4 marks · −1

The truth table for the circuit given below is : [A and NOT(B) into an AND gate; NOT(A) and B into a second AND gate; both into an OR gate giving Y]

Figure for question 41
  1. A.A B Y: 00 0; 10 1; 01 0; 11 0
  2. B.A B Y: 00 0; 01 1; 10 1; 11 0
  3. C.A B Y: 00 0; 10 0; 11 0; 01 1
  4. D.A B Y: 00 0; 11 1; 10 1; 01 1

Correct answer: B

Question 42

Physics · 4 marks · −1

A plane electromagnetic wave propagates along the +x direction in free space. The components of the electric field, E⃗\vec{E} and magnetic field, B⃗\vec{B} vectors associated with the wave in Cartesian frame are

  1. A.EzE_z, ByB_y
  2. B.ExE_x, ByB_y
  3. C.EyE_y, BxB_x
  4. D.EyE_y, BzB_z

Correct answer: D

Question 43

Physics · 4 marks · −1

Three equal masses m are kept at vertices (A, B, C) of an equilateral triangle of side a in free space. At t = 0, they are given an initial velocity V⃗A=V0AC⃗\vec{V}_A=V_0\vec{AC}, V⃗B=V0BA⃗\vec{V}_B=V_0\vec{BA} and V⃗C=V0CB⃗\vec{V}_C=V_0\vec{CB}. Here, AC⃗\vec{AC}, CB⃗\vec{CB} and BA⃗\vec{BA} are unit vectors along the edges of the triangle. If the three masses interact gravitationally, then the magnitude of the net angular momentum of the system at the point of collision is :

Figure for question 43
  1. A.32amV0\frac{\sqrt{3}}{2}amV_0
  2. B.32amV0\frac{3}{2}amV_0
  3. C.12amV0\frac{1}{2}amV_0
  4. D.3amV03amV_0

Correct answer: A

Explanation: L about centroid conserved: 3mV0⋅a23=32amV03mV_0\cdot\frac{a}{2\sqrt3}=\frac{\sqrt3}{2}amV_0.

Question 44

Physics · 4 marks · −1

The magnetic field inside a 200 turns solenoid of radius 10 cm is 2.9×10−42.9\times10^{-4} Tesla. If the solenoid carries a current of 0.29 A, then the length of the solenoid is ______ π cm.

Correct answer: 8

Explanation: L=μ0NIB=4π×10−7×200×0.292.9×10−4=0.08πL=\frac{\mu_0NI}{B}=\frac{4\pi\times10^{-7}\times200\times0.29}{2.9\times10^{-4}}=0.08\pi m = 8π cm.

Question 45

Physics · 4 marks · −1

Two planets, A and B are orbiting a common star in circular orbits of radii RAR_A and RBR_B, respectively, with RB=2RAR_B=2R_A. The planet B is 424\sqrt{2} times more massive than planet A. The ratio (LBLA)\left(\frac{L_B}{L_A}\right) of angular momentum (LBL_B) of planet B to that of planet A(LAL_A) is closest to integer ______.

Correct answer: 8

Explanation: L∝mrL\propto m\sqrt r: 42⋅2=84\sqrt2\cdot\sqrt2=8.

Question 46

Physics · 4 marks · −1

Two cars P and Q are moving on a road in the same direction. Accleration of car P increases linearly with time whereas car Q moves with a constant acceleration. Both cars cross each other at time t = 0, for the first time. The maximum possible number of crossing(s) (including the crossing at t = 0) is ______.

Correct answer: 3

Explanation: Relative position is a cubic in t with t = 0 a root: at most 3 crossings.

Question 47

Physics · 4 marks · −1

A physical quantity Q is related to four observables a, b, c, d as follows : Q=ab4cdQ=\frac{ab^4}{cd} where, a = (60 ± 3)Pa; b = (20 ± 0.1)m; c = (40 ± 0.2)N s m−2m^{-2} and d = (50 ± 0.1)m, then the percentage error in Q is x1000\frac{x}{1000}, where x = ______.

Correct answer: 7700

Explanation: 5 + 2 + 0.5 + 0.2 = 7.7% = 7700/1000.

Question 48

Physics · 4 marks · −1

A parallel plate capacitor consisting of two circular plates of radius 10 cm is being charged by a constant current of 0.15 A. If the rate of change of potential difference between the plates is 7×1087\times10^8 V/s then the integer value of the distance between the parallel plates is (Take, ϵ0=9×10−12\epsilon_0=9\times10^{-12} F/m, π = 22/7) ______ μm.

Correct answer: 1320

Explanation: d=ϵ0AIdVdt=9×10−12×227×10−2×7×1080.15=1320d=\frac{\epsilon_0A}{I}\frac{dV}{dt}=\frac{9\times10^{-12}\times\frac{22}{7}\times10^{-2}\times7\times10^8}{0.15}=1320 μm.

Question 49

Chemistry · 4 marks · −1

Match List - I with List - II : List - I (Applications): (A) Transistors (B) Hearing aids (C) Invertors (D) Apollo space ship. List - II (Batteries/Cell): (I) Anode - Zn/Hg ; Cathode - HgO + C (II) Hydrogen fuel cell (III) Anode - Zn ; Cathode - Carbon (IV) Anode - Pb ; Cathode - Pb|PbO2PbO_2. Choose the correct answer from the options given below :

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

Correct answer: B

Question 50

Chemistry · 4 marks · −1

Drug X becomes ineffective after 50% decomposition. The original concentration of drug in a bottle was 16 mg/mL which becomes 4 mg/mL in 12 months. The expiry time of the drug in months is ______. Assume that the decomposition of the drug follows first order kinetics.

  1. A.3
  2. B.12
  3. C.6
  4. D.2

Correct answer: C

Explanation: Two half-lives in 12 months: half-life 6 months.

Question 51

Chemistry · 4 marks · −1

The calculated spin-only magnetic moments of K3[Fe(OH)6]K_3[Fe(OH)_6] and K4[Fe(OH)6]K_4[Fe(OH)_6] respectively are :

  1. A.4.90 and 4.90 B.M.
  2. B.3.87 and 4.90 B.M.
  3. C.4.90 and 5.92 B.M.
  4. D.5.92 and 4.90 B.M.

Correct answer: D

Explanation: High-spin Fe3+Fe^{3+} (d5d^5) 5.92, Fe2+Fe^{2+} (d6d^6) 4.90.

Question 52

Chemistry · 4 marks · −1

Identify the essential amino acids from below : (A) Valine (B) Proline (C) Lysine (D) Threonine (E) Tyrosine. Choose the correct answer from the options given below :

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

Correct answer: B

Question 53

Chemistry · 4 marks · −1

Given below are two statements : Statement (I) : In partition chromatography, stationary phase is thin film of liquid present in the inert support. Statement (II) : In paper chromatography, the material of paper acts as a stationary phase. In the light of the above statements, choose the correct answer from the options given below :

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

Correct answer: C

Explanation: In paper chromatography the water held in the paper is the stationary phase.

Question 54

Chemistry · 4 marks · −1

For hydrogen like species, which of the following graphs provides the most appropriate representation of E vs Z plot for a constant n ? [E : Energy of the stationary state, Z : atomic number, n = principal quantum number]

Figure for question 54
  1. A.E positive, increasing linearly with Z
  2. B.E negative, becoming more negative as Z increases (downward parabola, E ∝ −Z²)
  3. C.E negative, decreasing linearly with Z
  4. D.E positive, increasing parabolically with Z

Correct answer: B

Explanation: E=−13.6Z2/n2E=-13.6Z^2/n^2.

Question 55

Chemistry · 4 marks · −1

Given below are two statements : Statement (I) : It is impossible to specify simultaneously with arbitrary precision, both the linear momentum and the position of a particle. Statement (II) : If the uncertainty in the measurement of position and uncertainty in measurement of momentum are equal for an electron, then the uncertainty in the measurement of velocity is ≥hπ×12m\ge\sqrt{\frac{h}{\pi}}\times\frac{1}{2m}. In the light of the above statements, choose the correct answer from the options given below :

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

Correct answer: D

Explanation: (Δp)2≥h4π(\Delta p)^2\ge\frac{h}{4\pi} ⇒ Δv≥12mhπ\Delta v\ge\frac{1}{2m}\sqrt{\frac h\pi}.

Question 56

Chemistry · 4 marks · −1

Which among the following halides will generate the most stable carbocation in the nucleophilic substitution reaction?

  1. A.Ph3C−BrPh_3C-Br
  2. B.PhCH2BrPhCH_2Br
  3. C.CH2=CH−CH2BrCH_2=CH-CH_2Br
  4. D.3-Bromocyclohexene

Correct answer: A

Question 57

Chemistry · 4 marks · −1

The type of oxide formed by the element among Li, Na, Be, Mg, B and Al that has the least atomic radius is :

  1. A.A2OA_2O
  2. B.AO2AO_2
  3. C.A2O3A_2O_3
  4. D.AO

Correct answer: C

Explanation: Boron is smallest: B2O3B_2O_3.

Question 58

Chemistry · 4 marks · −1

0.1 M solution of KI reacts with excess of H2SO4H_2SO_4 and KIO3KIO_3 solutions. According to equation 5I−+IO3−+6H+→3I2+3H2O5I^-+IO_3^-+6H^+\to3I_2+3H_2O. Identify the correct statements : (A) 200 mL of KI solution reacts with 0.004 mol of KIO3KIO_3 (B) 200 mL of KI solution reacts with 0.006 mol of H2SO4H_2SO_4 (C) 0.5 L of KI solution produced 0.005 mol of I2I_2 (D) Equivalent weight of KIO3KIO_3 is equal to (Molecular weight5)\left(\frac{\text{Molecular weight}}{5}\right). Choose the correct answer from the options given below :

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

Correct answer: C

Explanation: 0.02 mol I−I^- ⇒ 0.004 mol IO3−IO_3^- (A true), 0.024 mol H+H^+ = 0.012 mol H2SO4H_2SO_4 (B false); 0.05 mol I⁻ ⇒ 0.03 mol I2I_2 (C false); I(+5)→0: n-factor 5 (D true).

Question 59

Chemistry · 4 marks · −1

Consider the equilibrium CO(g)+3H2(g)⇌CH4(g)+H2O(g)CO(g)+3H_2(g)\rightleftharpoons CH_4(g)+H_2O(g). If the pressure applied over the system increases by two fold at constant temperature then (A) Concentration of reactants and products increases. (B) Equilibrium will shift in forward direction. (C) Equilibrium constant increases since concentration of products increases. (D) Equilibrium constant remains unchanged as concentration of reactants and products remain same. Choose the correct answer from the options given below :

  1. A.(A), (B) and (D) only
  2. B.(A) and (B) only
  3. C.(B) and (C) only
  4. D.(A), (B) and (C) only

Correct answer: B

Question 60

Chemistry · 4 marks · −1

First ionisation enthalpy values of first four group 15 elements are given below. Choose the correct value for the element that is a main component of apatite family :

  1. A.947 kJ mol−1mol^{-1}
  2. B.1402 kJ mol−1mol^{-1}
  3. C.834 kJ mol−1mol^{-1}
  4. D.1012 kJ mol−1mol^{-1}

Correct answer: D

Explanation: Apatite is a phosphate mineral: P, IE₁ = 1012 kJ/mol.

Question 61

Chemistry · 4 marks · −1

Which one of the following reaction sequences will give an azo dye ?

  1. A.Benzonitrile: (i) 70% H2SO4H_2SO_4 (ii) PCl5PCl_5 (iii) aniline
  2. B.Aniline: (i) HCl/NaNO2NaNO_2 (ii) toluene
  3. C.Benzenesulfonic acid: (i) SOCl2SOCl_2 (ii) NH3NH_3 (iii) benzyl chloride
  4. D.Nitrobenzene: (i) Sn/HCl (ii) NaNO2NaNO_2/HCl (iii) β-naphthol, NaOH

Correct answer: D

Question 62

Chemistry · 4 marks · −1

Total number of sigma (σ) ______ and pi (π) ______ bonds respectively present in hex-1-en-4-yne are :

  1. A.13 and 3
  2. B.3 and 13
  3. C.11 and 3
  4. D.14 and 3

Correct answer: A

Explanation: CH2=CH−CH2−C≡C−CH3CH_2=CH-CH_2-C\equiv C-CH_3 (C6H8C_6H_8): σ = 5 + 8 = 13, π = 3.

Question 63

Chemistry · 4 marks · −1

Given below are two statements : Statement (I) : NaCl is added to the ice at 0°C, present in the ice cream box to prevent the melting of ice cream. Statement (II) : On addition of NaCl to ice at 0°C, there is a depression in freezing point. 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.Both Statement I and Statement II are false
  3. C.Statement I is false but Statement II is true
  4. D.Both Statement I and Statement II are true

Correct answer: D

Question 64

Chemistry · 4 marks · −1

Which one of the following, with HBr will give a phenol ?

Figure for question 64
  1. A.PhCH2−O−C(CH3)3PhCH_2-O-C(CH_3)_3
  2. B.PhCH2−CH(OCH3)2PhCH_2-CH(OCH_3)_2
  3. C.PhCH2−OCH3PhCH_2-OCH_3
  4. D.Ph–O–CH3CH_3 (anisole)

Correct answer: D

Question 65

Chemistry · 4 marks · −1

Identify the homoleptic complexes with odd number of d electrons in the central metal : (A) [FeO4]2−[FeO_4]^{2-} (B) [Fe(CN)6]3−[Fe(CN)_6]^{3-} (C) [Fe(CN)5NO]2−[Fe(CN)_5NO]^{2-} (D) [CoCl4]2−[CoCl_4]^{2-} (E) [Co(H2O)3F3][Co(H_2O)_3F_3]. Choose the correct answer from the options given below :

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

Correct answer: C

Explanation: Homoleptic: A (d2d^2), B (d5d^5), D (d7d^7); odd: B and D.

Question 66

Chemistry · 4 marks · −1

If C(diamond) → C(graphite) + X kJ mol−1mol^{-1}; C(diamond) + O2O_2(g) → CO2CO_2(g) + Y kJ mol−1mol^{-1}; C(graphite) + O2O_2(g) → CO2CO_2(g) + Z kJ mol−1mol^{-1} at constant temperature. Then

  1. A.X = Y − Z
  2. B.X = Y + Z
  3. C.X = −Y + Z
  4. D.−X = Y + Z

Correct answer: A

Question 67

Chemistry · 4 marks · −1

O2O_2 gas will be evolved as a product of electrolysis of : (A) an aqueous solution of AgNO3AgNO_3 using silver electrodes. (B) an aqueous solution of AgNO3AgNO_3 using platinum electrodes. (C) a dilute solution of H2SO4H_2SO_4 using platinum electrodes. (D) a high concentration solution of H2SO4H_2SO_4 using platinum electrodes. Choose the correct answer from the options given below :

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

Correct answer: A

Question 68

Chemistry · 4 marks · −1

Given below are two statements : Statement (I) : On nitration of m-xylene with HNO3HNO_3, H2SO4H_2SO_4 followed by oxidation, 4-nitrobenzene-1,3-dicarboxylic acid is obtained as the major product. Statement (II) : −CH3CH_3 group is o/p-directing while −NO2NO_2 group is m-directing group. In the light of the above statements, choose the correct answer from the options given below :

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

Correct answer: A

Question 69

Chemistry · 4 marks · −1

In the Claisen-Schmidt reaction to prepare, dibenzalacetone from 5.3 g of benzaldehyde, a total of 3.51 g of product was obtained. The percentage yield in this reaction was ______ %.

Correct answer: 60

Explanation: 0.05 mol PhCHO → 0.025 mol product (234 g/mol) = 5.85 g; 3.51/5.85 = 60%.

Question 70

Chemistry · 4 marks · −1

In the sulphur estimation, 0.20 g of a pure organic compound gave 0.40 g of barium sulphate. The percentage of sulphur in the compound is ______ × 10−110^{-1} %. (Molar mass : O = 16, S = 32, Ba = 137 in g mol−1mol^{-1})

Correct answer: 275

Explanation: S = 0.40 × 32/233 = 0.0549 g → 27.5% ≈ 275 × 10⁻¹.

Question 71

Chemistry · 4 marks · −1

Consider the following low-spin complexes K3[Co(NO2)6]K_3[Co(NO_2)_6], K4[Fe(CN)6]K_4[Fe(CN)_6], K3[Fe(CN)6]K_3[Fe(CN)_6], Cu2[Fe(CN)6]Cu_2[Fe(CN)_6] and Zn2[Fe(CN)6]Zn_2[Fe(CN)_6]. The sum of the spin-only magnetic moment values of complexes having yellow colour is ______ B.M. (answer in nearest integer)

Correct answer: 0

Explanation: Yellow: K3[Co(NO2)6]K_3[Co(NO_2)_6] (0), K4[Fe(CN)6]K_4[Fe(CN)_6] (0), Zn2[Fe(CN)6]Zn_2[Fe(CN)_6] (0): sum 0.

Question 72

Chemistry · 4 marks · −1

Total number of non bonded electrons present in NO2−NO_2^- ion based on Lewis theory is ______.

Correct answer: 12

Explanation: O=N–O⁻: N has 1 lone pair, O’s have 2 + 3 lone pairs: 6 pairs = 12 electrons.

Question 73

Chemistry · 4 marks · −1

Isomeric hydrocarbons → negative Baeyer\'s test (Molecular formula C9H12C_9H_{12}). The total number of isomers from above with four different non-aliphatic substitution sites is -

Correct answer: 2

Explanation: Aromatic C9H12C_9H_{12} isomers (negative Baeyer test) are propyl-, isopropyl-, three ethylmethyl- and three trimethyl-benzenes; the NTA key counts 2 of them as having four distinct aromatic C–H positions.

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