JEE Main 2026 — 23 Jan Shift 1 (9:00 AM - 12:00 PM) (Previous Year

JEE Main · 2026 · 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 A={−2,−1,0,1,2,3,4}A=\{-2, -1, 0, 1, 2, 3, 4\}. Let R be a relation on A defined by xRyxRy if and only if 2x+y≤22x+y\le2. Let ll be the number of elements in R. Let m and n be the minimum number of elements required to be added in R to make it reflexive and symmetric relations respectively. Then l+m+nl+m+n is equal to :

  1. A.34
  2. B.35
  3. C.32
  4. D.33

Correct answer: D

Question 2

Mathematics · 4 marks · −1

If α\alpha and β\beta (α<β)(\alpha<\beta) are the roots of the equation (−2+3)(∣x−3∣)+(x−6x)+(9−23)=0(-2+\sqrt{3})(|\sqrt{x}-3|)+(x-6\sqrt{x})+(9-2\sqrt{3})=0, x≥0x\ge0, then βα+αβ\sqrt{\frac{\beta}{\alpha}}+\sqrt{\alpha\beta} is equal to :

  1. A.8
  2. B.11
  3. C.9
  4. D.10

Correct answer: D

Question 3

Mathematics · 4 marks · −1

A building construction work can be completed by two masons A and B together in 22.5 days. Mason A alone can complete the construction work in 24 days less than mason B alone. Then mason A alone will complete the construction work in :

  1. A.42 days
  2. B.24 days
  3. C.36 days
  4. D.30 days

Correct answer: C

Explanation: 1a+1a+24=245⇒a=36\frac1a+\frac1{a+24}=\frac{2}{45} \Rightarrow a=36.

Question 4

Mathematics · 4 marks · −1

Let S={z:3≤∣2z−3(1+i)∣≤7}S=\{z: 3\le|2z-3(1+i)|\le7\} be a set of complex numbers. Then min⁡z∈S∣z+12(5+3i)∣\min_{z\in S}\left|z+\frac{1}{2}(5+3i)\right| is equal to :

  1. A.2
  2. B.32\frac{3}{2}
  3. C.12\frac{1}{2}
  4. D.52\frac{5}{2}

Correct answer: B

Explanation: Annulus centre (32,32)\left(\frac32,\frac32\right), radii 32\frac32 to 72\frac72; point (−52,−32)\left(-\frac52,-\frac32\right) is at distance 5, so minimum 5−72=325-\frac72=\frac32.

Question 5

Mathematics · 4 marks · −1

Among the statements : I : If ∣1cos⁡αcos⁡βcos⁡α1cos⁡γcos⁡βcos⁡γ1∣=∣0cos⁡αcos⁡βcos⁡α0cos⁡γcos⁡βcos⁡γ0∣\begin{vmatrix}1 & \cos\alpha & \cos\beta\\ \cos\alpha & 1 & \cos\gamma\\ \cos\beta & \cos\gamma & 1\end{vmatrix}=\begin{vmatrix}0 & \cos\alpha & \cos\beta\\ \cos\alpha & 0 & \cos\gamma\\ \cos\beta & \cos\gamma & 0\end{vmatrix}, then cos⁡2α+cos⁡2β+cos⁡2γ=32\cos^2\alpha+\cos^2\beta+\cos^2\gamma=\frac{3}{2}, and II : If ∣x2+xx+1x−22x2+3x−13x3x−3x2+2x+32x−12x−1∣=px+q\begin{vmatrix}x^2+x & x+1 & x-2\\ 2x^2+3x-1 & 3x & 3x-3\\ x^2+2x+3 & 2x-1 & 2x-1\end{vmatrix}=px+q, then p2=196q2p^2=196q^2,

  1. A.both are true
  2. B.only I is true
  3. C.both are false
  4. D.only II is true

Correct answer: C

Question 6

Mathematics · 4 marks · −1

The sum of all possible values of n∈Nn\in\mathbb{N}, so that the coefficients of xx, x2x^2 and x3x^3 in the expansion of (1+x2)2(1+x)n(1+x^2)^2(1+x)^n, are in arithmetic progression is :

  1. A.9
  2. B.3
  3. C.7
  4. D.12

Correct answer: A

Question 7

Mathematics · 4 marks · −1

The value of 100C5051+100C5152+…+100C100101\frac{^{100}C_{50}}{51}+\frac{^{100}C_{51}}{52}+\ldots+\frac{^{100}C_{100}}{101} is :

  1. A.2100100\frac{2^{100}}{100}
  2. B.2101100\frac{2^{101}}{100}
  3. C.2101101\frac{2^{101}}{101}
  4. D.2100101\frac{2^{100}}{101}

Correct answer: D

Explanation: 100Crr+1=101Cr+1101\frac{^{100}C_r}{r+1}=\frac{^{101}C_{r+1}}{101}; ∑s=51101101Cs=2100\sum_{s=51}^{101}{}^{101}C_s=2^{100}, giving 2100101\frac{2^{100}}{101}.

Question 8

Mathematics · 4 marks · −1

Let the mean and variance of 8 numbers −10,−7,−1,x,y,9,2,16-10, -7, -1, x, y, 9, 2, 16 be 72\frac{7}{2} and 2934\frac{293}{4}, respectively. Then the mean of 4 numbers x,y,x+y+1,∣x−y∣x, y, x+y+1, |x-y| is :

  1. A.12
  2. B.10
  3. C.9
  4. D.11

Correct answer: D

Question 9

Mathematics · 4 marks · −1

A rectangle is formed by the lines x=0x=0, y=0y=0, x=3x=3 and y=4y=4. Let the line L be perpendicular to 3x+y+6=03x+y+6=0 and divide the area of the rectangle into two equal parts. Then the distance of the point (12,−5)\left(\frac{1}{2}, -5\right) from the line L is equal to :

  1. A.252\sqrt{5}
  2. B.2102\sqrt{10}
  3. C.3103\sqrt{10}
  4. D.10\sqrt{10}

Correct answer: B

Explanation: L passes through the centre (1.5,2)(1.5,2) with slope 13\frac13: x−3y+4.5=0x-3y+4.5=0; distance from (0.5,−5)(0.5,-5) is 2010=210\frac{20}{\sqrt{10}}=2\sqrt{10}.

Question 10

Mathematics · 4 marks · −1

Let the domain of the function f(x)=log⁡3log⁡5log⁡7(9x−x2−13)f(x)=\log_3\log_5\log_7(9x-x^2-13) be the interval (m,n)(m, n). Let the hyperbola x2a2−y2b2=1\frac{x^2}{a^2}-\frac{y^2}{b^2}=1 have eccentricity n3\frac{n}{3} and the length of the latus rectum 8m3\frac{8m}{3}. Then b2−a2b^2-a^2 is equal to :

  1. A.9
  2. B.11
  3. C.5
  4. D.7

Correct answer: D

Question 11

Mathematics · 4 marks · −1

Number of solutions of 3cos⁡2θ+8cos⁡θ+33=0\sqrt{3}\cos2\theta+8\cos\theta+3\sqrt{3}=0, θ∈[−3π,2π]\theta\in[-3\pi, 2\pi] is :

  1. A.4
  2. B.0
  3. C.3
  4. D.5

Correct answer: D

Question 12

Mathematics · 4 marks · −1

Let the line y−x=1y-x=1 intersect the ellipse x22+y21=1\frac{x^2}{2}+\frac{y^2}{1}=1 at the points A and B. Then the angle made by the line segment AB at the center of the ellipse is :

  1. A.π2−tan⁡−1(14)\frac{\pi}{2}-\tan^{-1}\left(\frac{1}{4}\right)
  2. B.π2+2tan⁡−1(14)\frac{\pi}{2}+2\tan^{-1}\left(\frac{1}{4}\right)
  3. C.π2+tan⁡−1(14)\frac{\pi}{2}+\tan^{-1}\left(\frac{1}{4}\right)
  4. D.π−tan⁡−1(14)\pi-\tan^{-1}\left(\frac{1}{4}\right)

Correct answer: C

Question 13

Mathematics · 4 marks · −1

Let α\alpha and β\beta respectively be the maximum and the minimum values of the function f(θ)=4(sin⁡4(7π2−θ)+sin⁡4(11π+θ))−2(sin⁡6(3π2−θ)+sin⁡6(9π−θ))f(\theta)=4\left(\sin^4\left(\frac{7\pi}{2}-\theta\right)+\sin^4(11\pi+\theta)\right)-2\left(\sin^6\left(\frac{3\pi}{2}-\theta\right)+\sin^6(9\pi-\theta)\right), θ∈R\theta\in\mathbb{R}. Then α+2β\alpha+2\beta is equal to :

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

Correct answer: C

Explanation: f=4(1−2s)−2(1−3s)=2−2sf=4(1-2s)-2(1-3s)=2-2s with s=sin⁡2θcos⁡2θ∈[0,14]s=\sin^2\theta\cos^2\theta\in[0,\frac14]: α=2\alpha=2, β=32\beta=\frac32, α+2β=5\alpha+2\beta=5.

Question 14

Mathematics · 4 marks · −1

The vertices B and C of a triangle ABC lie on the line x1=1−y−2=z−23\frac{x}{1}=\frac{1-y}{-2}=\frac{z-2}{3}. The coordinates of A and B are (1,6,3)(1, 6, 3) and (4,9,α)(4, 9, \alpha) respectively and C is at a distance of 10 units from B. The area (in sq. units) of ΔABC\Delta ABC is :

  1. A.101310\sqrt{13}
  2. B.151315\sqrt{13}
  3. C.5135\sqrt{13}
  4. D.201320\sqrt{13}

Correct answer: C

Question 15

Mathematics · 4 marks · −1

Let a⃗=−i^+j^+2k^\vec{a}=-\hat{i}+\hat{j}+2\hat{k}, b⃗=i^−j^−3k^\vec{b}=\hat{i}-\hat{j}-3\hat{k}, c⃗=a⃗×b⃗\vec{c}=\vec{a}\times\vec{b} and d⃗=c⃗×a⃗\vec{d}=\vec{c}\times\vec{a}. Then (a⃗−b⃗)⋅d⃗(\vec{a}-\vec{b})\cdot\vec{d} is equal to :

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

Correct answer: C

Question 16

Mathematics · 4 marks · −1

Let the direction cosines of two lines satisfy the equations : 4l+m−n=04l+m-n=0 and 2mn+10nl+3lm=02mn+10nl+3lm=0. Then the cosine of the acute angle between these lines is :

  1. A.10338\frac{10}{3\sqrt{38}}
  2. B.20338\frac{20}{3\sqrt{38}}
  3. C.10738\frac{10}{7\sqrt{38}}
  4. D.1038\frac{10}{\sqrt{38}}

Correct answer: A

Question 17

Mathematics · 4 marks · −1

Let f(x)={ax2+2ax+34x2+4x−3,x≠−32,12b,x=−32,12f(x)=\begin{cases}\frac{ax^2+2ax+3}{4x^2+4x-3}, & x\ne-\frac{3}{2}, \frac{1}{2}\\ b, & x=-\frac{3}{2}, \frac{1}{2}\end{cases} be continuous at x=−32x=-\frac{3}{2}. If f∘f(x)=75f\circ f(x)=\frac{7}{5}, then xx is equal to :

  1. A.0
  2. B.2
  3. C.1
  4. D.1.4

Correct answer: C

Question 18

Mathematics · 4 marks · −1

Let f(x)=∫(2−x2)⋅ex(1+x)(1−x)3/2dxf(x)=\int\frac{(2-x^2)\cdot e^x}{(\sqrt{1+x})(1-x)^{3/2}}dx. If f(0)=0f(0)=0, then f(12)f\left(\frac{1}{2}\right) is equal to :

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

Correct answer: B

Question 19

Mathematics · 4 marks · −1

The value of the integral ∫π/245π/24dx1+tan⁡2x3\int_{\pi/24}^{5\pi/24}\frac{dx}{1+\sqrt[3]{\tan2x}} is :

  1. A.π6\frac{\pi}{6}
  2. B.π18\frac{\pi}{18}
  3. C.π12\frac{\pi}{12}
  4. D.π3\frac{\pi}{3}

Correct answer: C

Explanation: King's property (2x→π2−2x2x\to\frac\pi2-2x) pairs the integrand with its complement: I=12⋅4π24=π12I=\frac12\cdot\frac{4\pi}{24}=\frac{\pi}{12}.

Question 20

Mathematics · 4 marks · −1

Let y=y(x)y=y(x) be the solution of the differential equation x4dy+(4x3y+2sin⁡x)dx=0x^4dy+(4x^3y+2\sin x)dx=0, x>0x>0, y(π2)=0y\left(\frac{\pi}{2}\right)=0. Then π4y(π3)\pi^4y\left(\frac{\pi}{3}\right) is equal to :

  1. A.92
  2. B.81
  3. C.72
  4. D.64

Correct answer: B

Explanation: d(x4y)=−2sin⁡x dx⇒x4y=2cos⁡xd(x^4y)=-2\sin x\,dx \Rightarrow x^4y=2\cos x; at π3\frac\pi3: π481y=1⇒π4y=81\frac{\pi^4}{81}y=1 \Rightarrow \pi^4y=81.

Question 21

Mathematics · 4 marks · −1

Let ∣A∣=6|A|=6, where A is a 3×33\times3 matrix. If ∣adj⁡(3adj⁡(A2⋅adj⁡(2A)))∣=2m⋅3n|\operatorname{adj}(3\operatorname{adj}(A^2\cdot\operatorname{adj}(2A)))|=2^m\cdot3^n, m,n∈Nm, n\in\mathbb{N}, then m+nm+n is equal to ______.

Correct answer: 62

Question 22

Mathematics · 4 marks · −1

The number of 4-letter words, with or without meaning, which can be formed using the letters PQRPQRSTUVP, is ______.

Correct answer: 1422

Question 23

Mathematics · 4 marks · −1

From the first 100 natural numbers, two numbers first a and then b are selected randomly without replacement. If the probability that a−b≥10a-b\ge10 is mn\frac{m}{n}, gcd⁡(m,n)=1\gcd(m, n)=1, then m+nm+n is equal to ______.

Correct answer: 311

Explanation: Pairs with a−b=d≥10a-b=d\ge10: ∑d=1099(100−d)=4095\sum_{d=10}^{99}(100-d)=4095; 40959900=91220\frac{4095}{9900}=\frac{91}{220}, sum 311.

Question 24

Mathematics · 4 marks · −1

Let ff be a twice differentiable non-negative function such that (f(x))2=25+∫0x((f(t))2+(f′(t))2)dt(f(x))^2=25+\int_0^x\left((f(t))^2+(f'(t))^2\right)dt. Then the mean of f(log⁡e(1)),f(log⁡e(2)),…,f(log⁡e(625))f(\log_e(1)), f(\log_e(2)), \ldots, f(\log_e(625)) is equal to ______.

Correct answer: 1565

Explanation: 2ff′=f2+f′2⇒f′=f2ff'=f^2+f'^2 \Rightarrow f'=f, f=5exf=5e^x; mean of 5⋅1,…,5⋅6255\cdot1,\ldots,5\cdot625 is 5×313=15655\times313=1565.

Question 25

Mathematics · 4 marks · −1

Let the area of the region bounded by the curve y=max⁡{sin⁡x,cos⁡x}y=\max\{\sin x, \cos x\}, lines x=0x=0, x=3π2x=\frac{3\pi}{2}, and the xx-axis be A. Then, A+A2A+A^2 is equal to ______.

Correct answer: 12

Question 26

Physics · 4 marks · −1

Four persons measure the length of a rod as 20.00 cm, 19.75 cm, 17.01 cm and 18.25 cm. The relative error in the measurement of average length of the rod is :

  1. A.0.24
  2. B.0.06
  3. C.0.18
  4. D.0.08

Correct answer: B

Explanation: Mean 18.75; mean absolute error (1.25+1.00+1.74+0.50)/4=1.12(1.25+1.00+1.74+0.50)/4=1.12; relative error ≈0.06\approx0.06.

Question 27

Physics · 4 marks · −1

An object is projected with kinetic energy K from a point A at an angle 60∘60^\circ with the horizontal. The ratio of the difference in kinetic energies at points B and C to that at point A (see figure), in the absence of air friction is :

Figure for question 27
  1. A.2:3
  2. B.1:2
  3. C.3:4
  4. D.1:4

Correct answer: C

Explanation: KB=Kcos⁡260∘=K/4K_B=K\cos^260^\circ=K/4, KC=KK_C=K: (K−K/4)/K=3:4(K-K/4)/K=3:4.

Question 28

Physics · 4 marks · −1

Two small balls with masses m and 2m are attached to both ends of a rigid rod of length d and negligible mass. If angular momentum of this system is L about an axis (A) passing through its centre of mass and perpendicular to the rod then angular velocity of the system about A is :

  1. A.2L5md2\frac{2L}{5md^2}
  2. B.43Lmd2\frac{4}{3}\frac{L}{md^2}
  3. C.32Lmd2\frac{3}{2}\frac{L}{md^2}
  4. D.2Lmd2\frac{2L}{md^2}

Correct answer: C

Explanation: I=μd2=23md2I=\mu d^2=\frac23md^2, ω=3L2md2\omega=\frac{3L}{2md^2}.

Question 29

Physics · 4 marks · −1

The moment of inertia of a square loop made of four uniform solid cylinders, each having radius R and length L (R<L) about an axis passing through the mid points of opposite sides, is (Take the mass of the entire loop as M) :

  1. A.34MR2+16ML2\frac{3}{4}MR^2+\frac{1}{6}ML^2
  2. B.38MR2+712ML2\frac{3}{8}MR^2+\frac{7}{12}ML^2
  3. C.38MR2+16ML2\frac{3}{8}MR^2+\frac{1}{6}ML^2
  4. D.34MR2+712ML2\frac{3}{4}MR^2+\frac{7}{12}ML^2

Correct answer: C

Question 30

Physics · 4 marks · −1

A small bob A of mass m is attached to a massless rigid rod of length 1 m pivoted at point P and kept at an angle of 60∘60^\circ with vertical as shown in figure. At distance of 1 m below point P, an identical bob B is kept at rest on a smooth horizontal surface that extends to a circular track of radius R as shown in figure. If bob B just manages to complete the circular path of radius R upto a point Q after being hit elastically by bob A, then radius R is ______ m.

Figure for question 30
  1. A.35\frac{3}{5}
  2. B.2−35\frac{2-\sqrt{3}}{5}
  3. C.15\frac{1}{5}
  4. D.2+35\frac{2+\sqrt{3}}{5}

Correct answer: C

Explanation: A falls l(1−cos⁡60∘)=0.5l(1-\cos60^\circ)=0.5 m: v=10v=\sqrt{10} m/s, fully transferred to B in the elastic collision. Just completing the loop needs v2=5gRv^2=5gR, so R=1050=15R=\frac{10}{50}=\frac15 m (NTA key).

Question 31

Physics · 4 marks · −1

Two blocks with masses 100 g and 200 g are attached to the ends of springs A and B as shown in figure. The energy stored in A is E. The energy stored in B, when spring constants kAk_A, kBk_B of A and B, respectively satisfy the relation 4kA=3kB4k_A=3k_B, is :

Figure for question 31
  1. A.3E
  2. B.43E\frac{4}{3}E
  3. C.4E
  4. D.2E

Correct answer: A

Explanation: U=(mg)22kU=\frac{(mg)^2}{2k}: UBUA=4⋅kAkB=3\frac{U_B}{U_A}=4\cdot\frac{k_A}{k_B}=3.

Question 32

Physics · 4 marks · −1

The strain-stress plot for materials A, B, C and D is shown in the figure. Which material has the largest Young's modulus ?

Figure for question 32
  1. A.A
  2. B.C
  3. C.B
  4. D.D

Correct answer: B

Explanation: Y=stress/strainY=\text{stress}/\text{strain} is largest for the shallowest strain-stress line, C.

Question 33

Physics · 4 marks · −1

In a perfectly inelastic collision, two spheres made of the same material with masses 15 kg and 25 kg, moving in opposite directions with speeds of 10 m/s and 30 m/s, respectively, strike each other and stick together. The rise in temperature (in ∘^\circC), if all the heat produced during the collision is retained by these spheres, is : (specific heat of sphere material 31 cal/kg.∘^\circC and 1 cal = 4.2 J)

  1. A.1.95
  2. B.1.15
  3. C.1.44
  4. D.1.75

Correct answer: C

Explanation: KE loss =12⋅15⋅2540⋅402=7500=\frac12\cdot\frac{15\cdot25}{40}\cdot40^2=7500 J; ΔT=750040×31×4.2=1.44∘\Delta T=\frac{7500}{40\times31\times4.2}=1.44^\circC.

Question 34

Physics · 4 marks · −1

In a screw gauge, the zero of the circular scale lies 3 divisions above the horizontal pitch line when their metallic studs are brought in contact. Using this instrument thickness of a sheet is measured. If pitch scale reading is 1 mm and the circular scale reading is 51 then the correct thickness of the sheet is ______ mm. [Assume least count is 0.01 mm]

  1. A.1.51
  2. B.1.54
  3. C.1.48
  4. D.1.50

Correct answer: B

Explanation: Zero lying above the line is a negative zero error (−0.03-0.03 mm): 1.51+0.03=1.541.51+0.03=1.54 mm.

Question 35

Physics · 4 marks · −1

A simple pendulum of string length 30 cm performs 20 oscillations in 10 s. The length of the string required for the pendulum to perform 40 oscillations in the same time duration is ______ cm. [Assume that the mass of the pendulum remains same.]

  1. A.7.5
  2. B.120
  3. C.0.75
  4. D.15

Correct answer: A

Explanation: Half the period needs a quarter of the length: 7.5 cm.

Question 36

Physics · 4 marks · −1

A 20 m long uniform copper wire held horizontally is allowed to fall under the gravity (g=10g=10 m/s2^2) through a uniform horizontal magnetic field of 0.5 Gauss perpendicular to the length of the wire. The induced EMF across the wire when it travells a vertical distance of 200 m is ______ mV.

  1. A.0.2100.2\sqrt{10}
  2. B.20010200\sqrt{10}
  3. C.2102\sqrt{10}
  4. D.201020\sqrt{10}

Correct answer: D

Explanation: v=4000=2010v=\sqrt{4000}=20\sqrt{10}; ε=0.5×10−4×20×2010=2010\varepsilon=0.5\times10^{-4}\times20\times20\sqrt{10}=20\sqrt{10} mV.

Question 37

Physics · 4 marks · −1

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Consider a ferromagnetic material : Assertion (A) : The individual atoms in a ferromagnetic material possess a magnetic dipole moment and interact with one another in such a way that they spontaneously align themselves forming domains. Reason (R) : At high enough temperature, the domain structure of ferromagnetic material disintegrates. Thus, magnetization will disappear at high enough temperature known as Curie temperature. In the light of the above statements, choose the correct answer from the options given below :

  1. A.(A) is false but (R) is true
  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 true but (R) is false

Correct answer: B

Question 38

Physics · 4 marks · −1

Match List - I with List - II. List - I (Relation): A. ∮E⃗⋅dl⃗=−ddt∮B⃗⋅da⃗\oint\vec{E}\cdot d\vec{l}=-\frac{d}{dt}\oint\vec{B}\cdot d\vec{a}; B. ∮B⃗⋅dl⃗=μ0(I+ϵ0dϕEdt)\oint\vec{B}\cdot d\vec{l}=\mu_0\left(I+\epsilon_0\frac{d\phi_E}{dt}\right); C. ∮E⃗⋅da⃗=1ϵ0∫Vρ dv\oint\vec{E}\cdot d\vec{a}=\frac{1}{\epsilon_0}\int_V\rho\,dv; D. ∮B⃗⋅dl⃗=μ0I\oint\vec{B}\cdot d\vec{l}=\mu_0I. List - II (Law): I. Ampere's circuital law; II. Faraday's laws of electromagnetic induction; III. Ampere - Maxwell law; IV. Gauss's law of electrostatics. Choose the correct answer from the options given below :

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

Correct answer: D

Question 39

Physics · 4 marks · −1

Two point charges 2q and q are placed at vertex A and centre of face CDEF of the cube as shown in figure. The electric flux passing through the cube is :

Figure for question 39
  1. A.3qϵ0\frac{3q}{\epsilon_0}
  2. B.3q4ϵ0\frac{3q}{4\epsilon_0}
  3. C.qϵ0\frac{q}{\epsilon_0}
  4. D.3q2ϵ0\frac{3q}{2\epsilon_0}

Correct answer: B

Explanation: Corner charge contributes 2q8ϵ0\frac{2q}{8\epsilon_0}, face-centre charge q2ϵ0\frac{q}{2\epsilon_0}: total 3q4ϵ0\frac{3q}{4\epsilon_0}.

Question 40

Physics · 4 marks · −1

A wire of uniform resistance λ\lambda Ω\Omega/m is bent into a circle of radius r and another piece of wire with length 2r is connected between points A and B (AOB) as shown in figure. The equivalent resistance between points A and B is ______ Ω\Omega.

Figure for question 40
  1. A.3πλr8\frac{3\pi\lambda r}{8}
  2. B.2πλr2\pi\lambda r
  3. C.(π+1)2rλ(\pi+1)2r\lambda
  4. D.6πλr3π+16\frac{6\pi\lambda r}{3\pi+16}

Correct answer: D

Explanation: Three parallel paths: quarter arc πrλ2\frac{\pi r\lambda}{2}, three-quarter arc 3πrλ2\frac{3\pi r\lambda}{2}, wire 2rλ2r\lambda: R=6πλr3π+16R=\frac{6\pi\lambda r}{3\pi+16}.

Question 41

Physics · 4 marks · −1

A thin prism with angle 5∘5^\circ of refractive index 1.72 is combined with another prism of refractive index 1.9 to produce dispersion without deviation. The angle of second prism is ______.

  1. A.4.5∘4.5^\circ
  2. B.5∘5^\circ
  3. C.4∘4^\circ
  4. D.6∘6^\circ

Correct answer: C

Explanation: 0.72×5=0.9A⇒A=4∘0.72\times5=0.9A \Rightarrow A=4^\circ.

Question 42

Physics · 4 marks · −1

Consider light travelling from a medium A to medium B separated by a plane interface. If the light undergoes total internal reflection during its travel from medium A to B and the speed of light in media A and B are 2.4×1082.4\times10^8 m/s and 2.7×1082.7\times10^8 m/s, respectively, then the value of critical angle is :

  1. A.sin⁡−1(98)\sin^{-1}\left(\frac{9}{8}\right)
  2. B.cos⁡−1(89)\cos^{-1}\left(\frac{8}{9}\right)
  3. C.tan⁡−1(817)\tan^{-1}\left(\frac{8}{\sqrt{17}}\right)
  4. D.cot⁡−1(313)\cot^{-1}\left(\frac{3}{\sqrt{13}}\right)

Correct answer: C

Explanation: sin⁡C=89\sin C=\frac{8}{9}, so tan⁡C=817\tan C=\frac{8}{\sqrt{17}}.

Question 43

Physics · 4 marks · −1

The de Broglie wavelength of an oxygen molecule at 27∘27^\circC is x×10−12x\times10^{-12} m. The value of xx is (take Planck's constant =6.63×10−34=6.63\times10^{-34} J.s, Boltzmann constant =1.38×10−23=1.38\times10^{-23} J/K, mass of oxygen molecule =5.31×10−26=5.31\times10^{-26} kg)

  1. A.24
  2. B.20
  3. C.26
  4. D.30

Correct answer: C

Explanation: λ=h3mkT≈2.6×10−11\lambda=\frac{h}{\sqrt{3mkT}}\approx2.6\times10^{-11} m.

Question 44

Physics · 4 marks · −1

In hydrogen atom spectrum, (R→R\to Rydberg's constant) A. the maximum wavelength of the radiation of Lyman series is 43R\frac{4}{3R} B. the Balmer series lies in the visible region of the spectrum C. the minimum wavelength of the radiation of Paschen series is 9R\frac{9}{R} D. the minimum wavelength of Lyman series is 54R\frac{5}{4R}. Choose the correct answer from the options given below :

  1. A.A, B and C Only
  2. B.A, B and D Only
  3. C.A, B Only
  4. D.B, D Only

Correct answer: A

Question 45

Physics · 4 marks · −1

Using a variable frequency a.c. voltage source the maximum current measured in the given LCR circuit is 50 mA for V=5sin⁡(100t)V=5\sin(100t). The values of L and R are shown in the figure. The capacitance of the capacitor (C) used is ______ μ\muF.

Figure for question 45

Correct answer: 50

Explanation: Imax=V0/R=50I_{max}=V_0/R=50 mA means resonance at ω=100\omega=100: C=1ω2L=50 μC=\frac{1}{\omega^2L}=50\ \muF.

Question 46

Physics · 4 marks · −1

In two separate Young's double-slit experimental set-ups and two monochromatic light sources of different wavelengths are used to get fringes of equal width. The ratios of the slits separations and that of the wavelengths of light used are 2:1 and 1:2 respectively. The corresponding ratio of the distances between the slits and the respective screens (D1/D2)(D_1/D_2) is ______.

Correct answer: 4

Explanation: β=λD/d\beta=\lambda D/d equal: D1D2=d1d2⋅λ2λ1=2×2=4\frac{D_1}{D_2}=\frac{d_1}{d_2}\cdot\frac{\lambda_2}{\lambda_1}=2\times2=4.

Question 47

Physics · 4 marks · −1

The equation of the electric field of an electromagnetic wave propagating through free space is given by: E=377sin⁡(6.27×103t−2.09×10−5x)E=\sqrt{377}\sin(6.27\times10^3t-2.09\times10^{-5}x) N/C. The average power of the electromagnetic wave is (1α)\left(\frac{1}{\alpha}\right) W/m2^2. The value of α\alpha is ______ (Take μ0ϵ0=377\sqrt{\frac{\mu_0}{\epsilon_0}}=377 in SI units)

Correct answer: 2

Explanation: I=E022Z0=3772×377=12I=\frac{E_0^2}{2Z_0}=\frac{377}{2\times377}=\frac12, α=2\alpha=2.

Question 48

Physics · 4 marks · −1

A simple pendulum made of mass 10 g and a metallic wire of length 10 cm is suspended vertically in a uniform magnetic field of 2 T. The magnetic field direction is perpendicular to the plane of oscillations of the pendulum. If the pendulum is released from an angle of 60∘60^\circ with vertical, then maximum induced EMF between the point of suspension and point of oscillation is ______ mV. (Take g=10g=10 m/s2^2)

Correct answer: 100

Explanation: vmax=2gl(1−cos⁡60∘)=1v_{max}=\sqrt{2gl(1-\cos60^\circ)}=1 m/s; ε=12Bωl2=12Bvl=12⋅2⋅1⋅0.1=0.1\varepsilon=\frac12B\omega l^2=\frac12Bvl=\frac12\cdot2\cdot1\cdot0.1=0.1 V =100=100 mV.

Question 49

Physics · 4 marks · −1

The space between the plates of a parallel plate capacitor of capacitance C (without any dielectric) is now filled with three dielectric slabs of dielectric constants K1=2K_1=2, K2=3K_2=3 and K3=5K_3=5 (as shown in figure). If new capacitance is n3C\frac{n}{3}C then the value of nn is ______.

Figure for question 49

Correct answer: 8

Explanation: C1=4CC_1=4C, lower part C2=2ϵ0d(3⋅A2+5⋅A2)=8CC_2=\frac{2\epsilon_0}{d}(3\cdot\frac A2+5\cdot\frac A2)=8C; series: 3212C=83C\frac{32}{12}C=\frac83C, n=8n=8.

Question 50

Chemistry · 4 marks · −1

Which of the following statements regarding the energy of the stationary state is **true** in the following one - electron systems ?

  1. A.+8.72×10−18+8.72\times10^{-18} J for first orbit of He+^+ ion
  2. B.+2.18×10−18+2.18\times10^{-18} J for second orbit of He+^+ ion
  3. C.−2.18×10−18-2.18\times10^{-18} J for third orbit of Li2+^{2+} ion
  4. D.−1.09×10−18-1.09\times10^{-18} J for second orbit of H atom.

Correct answer: C

Explanation: E=−2.18×10−18Z2n2E=-2.18\times10^{-18}\frac{Z^2}{n^2} J; Li2+^{2+}, n=3n=3: −2.18×10−18-2.18\times10^{-18} J.

Question 51

Chemistry · 4 marks · −1

Given, (A) n=5n=5, ml=−1m_l=-1 (B) n=3n=3, l=2l=2, ml=−1m_l=-1, ms=+12m_s=+\frac{1}{2}. The maximum number of electron(s) in an atom that can have the quantum numbers as given in (A) and (B) respectively are :

  1. A.8 and 1
  2. B.26 and 1
  3. C.2 and 4
  4. D.4 and 1

Correct answer: A

Explanation: (A) l=1,2,3,4l=1,2,3,4 each give one orbital with ml=−1m_l=-1: 8 electrons. (B) 1 electron.

Question 52

Chemistry · 4 marks · −1

Identify the molecule (X) with maximum number of lone pairs of electrons (obtained using Lewis dot structure) among HNO3_3, H2_2SO4_4, NF3_3 and O3_3. Choose the **correct** bond angle made by the central atom of the molecule (X).

  1. A.116∘116^\circ
  2. B.120∘120^\circ
  3. C.107∘107^\circ
  4. D.102∘102^\circ

Correct answer: D

Explanation: NF3_3 has 10 lone pairs (9 on F + 1 on N); F−-N−-F angle ≈102∘\approx102^\circ.

Question 53

Chemistry · 4 marks · −1

A cup of water at 5∘5^\circC (system) is placed in a microwave oven and the oven is turned on for one minute during which the water begins to boil. Which of the following option is **true** ?

  1. A.q = +ve, w = 0, Δ\DeltaU = −-ve
  2. B.q = +ve, w = −-ve, Δ\DeltaU = +ve
  3. C.q = +ve, w = −-ve, Δ\DeltaU = −-ve
  4. D.q = −-ve, w = −-ve, Δ\DeltaU = −-ve

Correct answer: B

Question 54

Chemistry · 4 marks · −1

Which one of the following graphs accurately represents the plot of partial pressure of CS2_2 vs its mole fraction in a mixture of acetone and CS2_2 at constant temperature ?

Figure for question 54
  1. A.Negative-deviation set of curves (below Raoult lines)
  2. B.Ideal straight Raoult's-law lines
  3. C.Positive-deviation set of curves including total pressure (above Raoult lines)
  4. D.Single CS2_2 curve above Raoult's line, approaching Henry's-law line at low xx and Raoult's line near x=1x=1

Correct answer: D

Question 55

Chemistry · 4 marks · −1

Consider the general reaction given below at 400 K: xxA(g) ⇌\rightleftharpoons yyB(g). The values of KpK_p and KcK_c are studied under the same condition of temperature but variation in xx and yy. (i) Kp=85.87K_p=85.87 and Kc=2.586K_c=2.586 appropriate units (ii) Kp=0.862K_p=0.862 and Kc=28.62K_c=28.62 appropriate units. The values of xx and yy in (i) and (ii) respectively are :

  1. A.(i) 4, 1; (ii) 4, 1
  2. B.(i) 3, 1; (ii) 3, 1
  3. C.(i) 1, 3; (ii) 2, 1
  4. D.(i) 1, 2; (ii) 2, 1

Correct answer: D

Explanation: RT=32.8RT=32.8: (i) Kp/Kc=33.2≈RTK_p/K_c=33.2\approx RT, Δn=1\Delta n=1; (ii) Kp/Kc=0.030≈(RT)−1K_p/K_c=0.030\approx(RT)^{-1}, Δn=−1\Delta n=-1.

Question 56

Chemistry · 4 marks · −1

In the given electrochemical cell, Ag(s) | AgCl(s) | FeCl2_2(aq), FeCl3_3(aq) | Pt(s) at 298 K, the cell potential (EcellE_{cell}) will increase when : A. Concentration of Fe2+^{2+} is increased. B. Concentration of Fe3+^{3+} is decreased. C. Concentration of Fe2+^{2+} is decreased. D. Concentration of Fe3+^{3+} is increased. E. Concentration of Cl−^- is increased. Choose the **correct** answer from the options given below :

  1. A.A and E Only
  2. B.B Only
  3. C.C, D and E Only
  4. D.A and B Only

Correct answer: C

Question 57

Chemistry · 4 marks · −1

The correct trend in the first ionization enthalpies of the elements in the 3rd^{rd} period of periodic table is :

  1. A.Al<Si<S<P<Cl
  2. B.Si<S<Al<P<Cl
  3. C.S<Si<Al<P<Cl
  4. D.Al<S<P<Si<Cl

Correct answer: A

Question 58

Chemistry · 4 marks · −1

The correct statements from the following are : A. Ionic radii of trivalent cations of group 13 elements decreases down the group. B. Electronegativity of group 13 elements decreases down the group. C. Among the group 13 elements, Boron has highest first ionisation enthalpy. D. The trichloride and triiodide of group 13 elements are covalent in nature. Choose the **correct** answer from the options given below :

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

Correct answer: A

Question 59

Chemistry · 4 marks · −1

Given below are two statements : Statement I : [CoBr4_4]2−^{2-} ion will absorb light of lower energy than [CoCl4_4]2−^{2-} ion. Statement II : In [CoI4_4]2−^{2-} ion, the energy separation between the two set of d-orbitals is more than [CoCl4_4]2−^{2-} ion. 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: C

Question 60

Chemistry · 4 marks · −1

The statements that are **incorrect** about the nickel(II) complex of dimethylglyoxime are : A. It is red in colour. B. It has a high solubility in water at pH = 9. C. The Ni ion has two unpaired d-electrons. D. The N−-Ni−-N bond angle is almost close to 90∘90^\circ. E. The complex contains four five-membered metallacycles (metal containing rings). Choose the **correct** answer from the options given below :

  1. A.C and E Only
  2. B.B, C and E Only
  3. C.A, D and B Only
  4. D.C and D Only

Correct answer: B

Question 61

Chemistry · 4 marks · −1

Match List - I with List - II. List - I (Functional group (detection)): A. Unsaturation (Baeyer's test); B. Alcoholic group (Ceric ammonium nitrate test); C. Aldehyde group (Tollen's reagent); D. Phenolic group (FeCl3_3 test). List - II (Change observed during detection): I. Red colour appears; II. Silver mirror appears; III. Violet colour appears; IV. Discharge of pink colour. Choose the **correct** answer from the options given below :

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

Correct answer: A

Question 62

Chemistry · 4 marks · −1

Given below are two statements : Statement I : Sublimation is used for the separation and purification of compounds with low melting point. Statement II : The boiling point of a liquid increases as the external pressure is reduced. 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: A

Question 63

Chemistry · 4 marks · −1

Consider the following compounds: (a) chlorobenzene, (b) nitrobenzene, (c) anisole (C6_6H5_5OCH3_3). Arrange these compounds in the increasing order of reactivity with nitrating mixture.

  1. A.c < b < a
  2. B.b < c < a
  3. C.b < a < c
  4. D.c < a < b

Correct answer: C

Question 64

Chemistry · 4 marks · −1

But-2-yne and hydrogen (one mole each) are separately treated with (i) Pd/C and (ii) Na/liq. NH3_3 to give the products X and Y respectively. Identify the **incorrect** statements. A. X and Y are stereoisomers. B. Dipole moment of X is zero. C. Boiling point of X is higher than Y. D. X and Y react with O3_3/Zn + H2_2O to give different products. Choose the **correct** answer from the options given below :

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

Correct answer: D

Explanation: X = cis-but-2-ene (polar, higher b.p.), Y = trans; both ozonolyse to acetaldehyde. Incorrect: B and D.

Question 65

Chemistry · 4 marks · −1

(1-Bromoethyl)benzene (X, C6_6H5_5CH(Br)CH3_3) →?\xrightarrow{?} phenylacetic acid (Y, C6_6H5_5CH2_2COOH). The correct sequence of reagents for the above conversion of X to Y is :

  1. A.(i) NaOH (aq) (ii) Jones reagent (iii) H3_3O+^+
  2. B.(i) NaOEt (ii) B2_2H6_6/H2_2O2_2 (iii) Jones reagent
  3. C.(i) B2_2H6_6/H2_2O2_2 (ii) NaOEt (iii) Jones reagent
  4. D.(i) Jones reagent (ii) NaOEt (iii) Hot KMnO4_4/KOH

Correct answer: B

Explanation: Elimination to styrene, anti-Markovnikov hydroboration to 2-phenylethanol, Jones oxidation to the acid.

Question 66

Chemistry · 4 marks · −1

'xx' is the product which is obtained from propanenitrile and stannous chloride in the presence of hydrochloric acid followed by hydrolysis. 'yy' is the product which is obtained from the but-2-ene by the ozonolysis followed by hydrolysis. From the following, which product is not obtained when one mole of 'xx' and one mole of 'yy' react with each other in the presence of alkali followed by heating ?

  1. A.Pent-2-enal
  2. B.2-Methylpent-2-enal
  3. C.3-Methylbut-2-enal
  4. D.2-Methylbut-2-enal

Correct answer: C

Explanation: x = propanal, y = ethanal; the four aldol products are but-2-enal, 2-methylpent-2-enal, pent-2-enal and 2-methylbut-2-enal. 3-Methylbut-2-enal is not formed.

Question 67

Chemistry · 4 marks · −1

Compound 'P' undergoes the following sequence of reactions : 'P' →(i) NH3; (ii) Δ\xrightarrow{\text{(i) NH}_3\text{; (ii) }\Delta} Q →(i) KOH, Br2; (ii) CHCl3, KOH (alc), Δ\xrightarrow{\text{(i) KOH, Br}_2\text{; (ii) CHCl}_3\text{, KOH (alc), }\Delta} cyclohexyl isocyanide (C6_6H11_{11}NC). 'P' is :

  1. A.Cyclohexanecarboxamide (C6_6H11_{11}CONH2_2)
  2. B.Cyclohexylacetaldehyde (C6_6H11_{11}CH2_2CHO)
  3. C.1-Cyclohexylbutan-2-one type ketone (C6_6H11_{11}CH2_2COCH2_2CH3_3)
  4. D.Cyclohexanecarboxylic acid (C6_6H11_{11}COOH)

Correct answer: D

Question 68

Chemistry · 4 marks · −1

Consider the following sequence of reactions. 4-Nitrotoluene →(i) Sn, HCl/Δ; (ii) pH neutralisation\xrightarrow{\text{(i) Sn, HCl}/\Delta\text{; (ii) pH neutralisation}} (A) →(i) (H3CCO)2O; (ii) Br2/AcOH\xrightarrow{\text{(i) (H}_3\text{CCO)}_2\text{O; (ii) Br}_2\text{/AcOH}} (B). Assuming that the reaction proceeds to completion, then 137 mg of 4-nitrotoluene will produce ______ mg of B. (Given molar mass in g mol−1^{-1} H : 1, C : 12, N : 14, O : 16, Br : 80)

  1. A.301
  2. B.208
  3. C.228
  4. D.146

Correct answer: C

Explanation: B = N-(2-bromo-4-methylphenyl)acetamide, C9_9H10_{10}BrNO (228); 1 mmol gives 228 mg.

Question 69

Chemistry · 4 marks · −1

From the given following (A to D) cyclic structures, those which will not react with Tollen's reagent are : A: pyranose sugar with free anomeric OH; B: methyl pyranoside (anomeric OCH3_3); C: methyl furanoside (anomeric OCH3_3); D: pyranose sugar with free anomeric OH.

Figure for question 69
  1. A.A and D
  2. B.B and C
  3. C.A and B
  4. D.B and D

Correct answer: B

Explanation: Glycosides (B, C) cannot open to the free aldehyde.

Question 70

Chemistry · 4 marks · −1

xx mg of pure HCl was used to make an aqueous solution. 25.0 mL of 0.1 M Ba(OH)2_2 solution is used when the HCl solution was titrated against it. The numerical value of xx is ______ ×10−1\times10^{-1}. (Nearest integer) Given : Molar mass of HCl and Ba(OH)2_2 are 36.5 and 171.0 g mol−1^{-1} respectively.

Correct answer: 1825

Explanation: 5 mmol HCl = 182.5 mg = 1825 ×10−1\times10^{-1}.

Question 71

Chemistry · 4 marks · −1

For the following gas phase equilibrium reaction at constant temperature, NH3_3(g) ⇌\rightleftharpoons 12\frac{1}{2}N2_2(g) + 32\frac{3}{2}H2_2(g), if the total pressure is 3\sqrt{3} atm and the pressure equilibrium constant (KpK_p) is 9 atm, then the degree of dissociation is given as (x×10−2)−1/2(x\times10^{-2})^{-1/2}. The value of xx is ______. (nearest integer)

Correct answer: 125

Explanation: Kp=274α21−α2P=9α24(1−α2)=9⇒α2=45K_p=\frac{\sqrt{27}}{4}\frac{\alpha^2}{1-\alpha^2}P=\frac{9\alpha^2}{4(1-\alpha^2)}=9 \Rightarrow \alpha^2=\frac45, α=(1.25)−1/2\alpha=(1.25)^{-1/2}, x=125x=125.

Question 72

Chemistry · 4 marks · −1

For the thermal decomposition of reactant AB(g), the following plot is constructed: [AB]/M decreases linearly with time: 0.6 M at t=0t=0, 0.55 M at 100 s and 0.5 M at 200 s. The half life of the reaction is 'xx' min. xx = ______ min. (Nearest integer)

Figure for question 72

Correct answer: 10

Explanation: Zero order, k=5×10−4k=5\times10^{-4} M/s; t1/2=0.62k=600t_{1/2}=\frac{0.6}{2k}=600 s = 10 min.

Question 73

Chemistry · 4 marks · −1

The crystal field splitting energy of [Co(oxalate)3_3]3−^{3-} complex is 'n' times that of the [Cr(oxalate)3_3]3−^{3-} complex. Here 'n' is ______. (Assume Δo>>P\Delta_o>>P)

Correct answer: 2

Explanation: Interpreted as CFSE: low-spin d6^6 −2.4Δo-2.4\Delta_o vs d3^3 −1.2Δo-1.2\Delta_o, n = 2.

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