Practice problems on JEE Mains, JEE Mains 2021 Feb 26 Shift 2

Question 1

A particle executes S.H.M., the graph of velocity as a function of displacement is :

Accepted Answer

An ellipse

Answer

A parabola

Answer

A helix

Answer

A circle

Question 2

The recoil speed of a hydrogen atom after it emits a photon in going from n = 5 state to n = 1 state will be :

Accepted Answer

4.17 m/s

Answer

4.34 m/s

Answer

2.19 m/s

Answer

3.25 m/s

Question 3

Let F1​(A,B,C)=∣(A∧∼B)∨[∼C∧(A∨B)]∨∼A and F2​(A,B)=(A∨B)∨(B→∼A) be two Logical expressions. Then :

Accepted Answer

F1​ is not a tautology but F2​ is a tautology

Answer

F1​ and F2​ both are tautologies

Answer

Both F1​ and F2​ are not tautologies

Answer

F1​ is a tautology but F2​ is not a tautology

Question 4

A. Phenyl methanamineB. N,N-DimethylanilineC. N-Methyl anilineD. BenzenamineChoose the correct order of basic nature of the above amines.

Accepted Answer

A > B > C > D

Answer

A > C > B > D

Answer

D > B > C > A

Answer

D > C > B > A

Question 5

Match List-I with List-II.Chose the correct answer from the options given below:

Accepted Answer

(a) → (iv), (b) → (iii), (c) → (i), (d) → (ii)

Answer

(a) → (i), (b) → (iii), (c) → (iv), (d) → (ii)

Answer

(a) → (iii), (b) → (ii), (c) → (i), (d) → (iv)

Answer

(a) → (iv), (b) → (i), (c) → (ii), (d) → (iii)

Question 6

Match List-I with List-II.Choose the correct answer from the options given below :

Accepted Answer

(a) → (ii), (b) → (i), (c) → (iii)

Answer

(a) → (i), (b) → (iii), (c) → (ii)

Answer

(a) → (iii), (b) → (ii), (c) → (i)

Answer

(a) → (iii), (b) → (i), (c) → (ii)

Question 7

Match List-I with List-II.Choose the correct answer from the options given below :

Accepted Answer

(a) (iii), (b) (v), (c) (i), (d) (iv)

Answer

(a) (i), (b) (ii), (c) (iii), (d) (iv)

Answer

(a) (i), (b) (ii), (c) (v), (d) (iii)

Answer

(a) (iii), (b) (i), (c) (v), (d) (ii)

Question 8

Let A1​ be the area of the region bounded by the curves y=sinx,y=cosx and y-axis in the first quadrant. Also, let A2​ be the area of the region bounded by the curves y = sin x, y = cos x, x-axis and x=2π​ in the first quadrant. Then,

Accepted Answer

A1​:A2​=1:2​ and A1​+A2​=1

Answer

A1​:A2​=1:2 and A1​+A2​=1

Answer

2A1​=A2​ and A1​+A2​=1+2​

Answer

A1​=A2​ and A1​+A2​=2​

Question 9

Match list-I with list-IIChoose the correct answer from the options given below :

Accepted Answer

(a)-(iii); (b)-(iv); (c)-(i); (d)-(ii)

Answer

(a)-(iv); (b)-(iii); (c)-(ii); (d)-(i)

Answer

(a)-(ii); (b)-(i); (c)-(iv); (d)-(iii)

Answer

(a)-(i); (b)-(ii); (c)-(iii); (d)-(iv)

Question 10

An inclined plane making an angle of 30º with the horizontal is placed in a uniform horizontal electric field 200CN​ as shown in the figure. A body of mass 1 kg and charge 5 mC is allowed to slide down from rest at a height of1 m. If the coefficient of friction is 0.2, find the time taken by the body to reach the bottom.[g=9.8 m/s2;sin30∘=21​;cos30∘=23​​]

Accepted Answer

1.3 s

Answer

2.3 s

Answer

0.92 s

Answer

0.46 s

Question 11

Two masses A and B, each of mass M are fixed together by a massless spring. A force acts on the mass B as shown in figure. If the mass A starts moving away from mass B with acceleration ‘a’, then the acceleration of mass B will be :

Accepted Answer

MF+Ma​

Answer

MMa−F​

Answer

F+MaMF​

Answer

MF−Ma​

Question 12

The incident ray, reflected ray and the outward drawn normal are denoted by the unit vectors a,b and c respectively. Then choose the correct relation for these vectors.

Accepted Answer

b=a−2(a⋅c)c

Answer

b=a+2c

Answer

b=2a+c

Answer

b=a−c

Question 13

Given below are two statements :Statement I : An electric dipole is placed at the centre of a hollow sphere. The flux of electric field through the sphere is zero but the electric field is not zero anywhere in the sphere.Statement II : If R is the radius of a solid metallic sphere and Q be the total charge on it. The electric field at any point on the spherical surface of radius r (In the light of the above statements, choose the correct answer from the options given below.

Accepted Answer

Statement I is true but Statement II is false

Answer

Statement I is false but Statement II is true

Answer

Both Statement I and Statement II are false

Answer

Both Statement I and Statement II are true

Question 14

Match List-I with List-IIChoose the correct answer from the options given below :

Accepted Answer

(a)-(ii); (b)-(iv); (c)-(i); (d)-(iii)

Answer

(a)-(iii); (b)-(iv); (c)-(i); (d)-(ii)

Answer

(a)-(iii); (b)-(i); (c)-(iv); (d)-(ii)

Answer

(a)-(ii); (b)-(i); (c)-(iv); (d)-(iii)

Question 15

A scooter accelerates from rest for time t1​ at constant rate a1​ and then retards at constant rate a2​ for time t2​ and comes to rest. The correct value of t2​t1​​ will be :

Accepted Answer

a1​a2​​

Answer

a1​a1​+a2​​

Answer

a2​a1​​

Answer

a2​a1​+a2​​