Other Physics · JEE Main previous year questions

383 questions asked across 19 exam years, newest first

Year-wise papers Topic-wise questions

Practise this topic

2021 43 questions

Q442021 · 20 Jul 2021 · Shift 1
If $A$ and $B$ are two vectors satisfying the relation $A \cdot B = A \times B$ . Then the value of $A - B$ will be :
1. A. $A^{2} + B^{2} + 2 A B$
2. B. $A^{2} + B^{2}$
3. C. $A^{2} + B^{2} - 2 A B$
4. D. $A^{2} + B^{2} + 2 A B$
Show answer
Answer: C
Q452021 · 20 Jul 2021 · Shift 1
The entropy of any system is given by $S = α^{2} β ln [\frac{μ k R}{J β ^{2}} + 3]$ where $α$ and $β$ are the constants. $μ$ , J, k and R are no. of moles, mechanical equivalent of heat, Boltzmann constant and gas constant respectively. [Take $S = \frac{d Q}{T}$ ] Choose the incorrect option from the following :
1. A. $α$ and J have the same dimensions.
2. B.S and $α$ have different dimensions
3. C.S, $β$ , k and $μ R$ have the same dimensions
4. D. $α$ and k have the same dimensions
Show answer
Answer: D
Q472021 · 20 Jul 2021 · Shift 1
1. A. $55.44 cm$
2. B. $18.23 cm$
3. C. $9.52 cm$
4. D. $37.58 cm$
Show answer
Answer: D
Q482021 · 20 Jul 2021 · Shift 1
1. A.(b)
2. B.(c)
3. C.(d)
4. D.(a)
Show answer
Answer: B
Q492021 · 20 Jul 2021 · Shift 1
The value of tension in a long thin metal wire has been changed from $T_{1}$ to $T_{2}$ . The lengths of the metal wire at two different values of tension $T_{1}$ and $T_{2}$ are $l_{1}$ and $l_{2}$ respectively. The actual length of the metal wire is :
1. A. $\frac{l _{1} + l _{2}}{2}$
2. B. $T_{1} T_{2} l_{1} l_{2}$
3. C. $\frac{T _{1} l _{2} - T _{2} l _{1}}{T _{1} - T _{2}}$
4. D. $\frac{T _{1} l _{1} - T _{2} l _{2}}{T _{1} - T _{2}}$
Show answer
Answer: C
Q552021 · 20 Jul 2021 · Shift 1· Numerical answer
The amplitude of wave disturbance propagating in the positive x-direction is given by $y = \frac{1}{1 + x ^{2}}$ at time $t = 0$ and $y = \frac{1}{1 + ( x - 2 ) ^{2}}$ at $t = 1 s$ , where x and y are in metres. The shape of wave does not change during the propagation. The velocity of the wave will be ________ m/s.
Show answer
Answer: 2
Q582021 · 20 Jul 2021 · Shift 1· Numerical answer
Show answer
Answer: 100
Q392021 · 18 Mar 2021 · Shift 1
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: B
Q432021 · 18 Mar 2021 · Shift 1
Your friend is having eye sight problem. She is not able to see clearly a distant uniform window mesh and it appears to her as non-uniform and distorted. The doctor diagnosed the problem as :
1. A.Astigmatism
2. B.Myopia with Astigmatism
3. C.Presbyopia with Astigmatism
4. D.Myopia and Hypermetropia
Show answer
Answer: B
Q492021 · 18 Mar 2021 · Shift 1
Match List - I with List - II. List - I (a) 10 km height over earth's surface (b) 70 km height over earth's surface (c) 180 km height over earth's surface (d) 270 km height over earth's surface List - II (i) Thermosphere (ii) Mesosphere (iii) Stratosphere (iv) Troposphere
1. A.(a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
2. B.(a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)
3. C.(a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
4. D.(a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)
Show answer
Answer: A
Q542021 · 18 Mar 2021 · Shift 1· Numerical answer
Two separate wires A and B are stretched by 2 mm and 4 mm respectively, when they are subjected to a force of 2 N. Assume that both the wires are made up of same material and the radius of wire B is 4 times that of the radius of wire A. The length of the wires A and B are in the ratio of a : b. Then a/b can be expressed as 1/x where x is _________.
Show answer
Answer: 32
Q582021 · 18 Mar 2021 · Shift 1· Numerical answer
Show answer
Answer: 10
Q592021 · 18 Mar 2021 · Shift 1· Numerical answer
A bullet of mass 0.1 kg is fired on a wooden block to pierce through it, but it stops after moving a distance of 50 cm into it. If the velocity of bullet before hitting the wood is 10 m/s and it slows down with uniform deceleration, then the magnitude of effective retarding force on the bullet is 'x' N. The value of 'x' to the nearest integer is __________.
Show answer
Answer: 10
Q352021 · 18 Mar 2021 · Shift 2
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: B
Q532021 · 18 Mar 2021 · Shift 2· Numerical answer
A galaxy is moving away from the earth at a speed of $286 km s^{- 1}$ . The shift in the wavelength of a redline at $630 nm$ is $x \times 1 0^{- 10} m$ . The value of x, to the nearest integer, is ____. [Take the value of speed of light c, as $3 \times 1 0^{8} m s^{- 1}$ ]
Show answer
Answer: 6
Q552021 · 18 Mar 2021 · Shift 2· Numerical answer
Show answer
Answer: 3
Q412021 · 16 Mar 2021 · Shift 1
The maximum and minimum distances of a comet from the Sun are $1.6 \times 1 0^{12} m$ and $8.0 \times 1 0^{10} m$ respectively. If the speed of the comet at the nearest point is $6 \times 1 0^{4} m s^{- 1}$ , the speed at the farthest point is :
1. A. $3.0 \times 1 0^{3} m/s$
2. B. $6.0 \times 1 0^{3} m/s$
3. C. $1.5 \times 1 0^{3} m/s$
4. D. $4.5 \times 1 0^{3} m/s$
Show answer
Answer: A
Q602021 · 16 Mar 2021 · Shift 1· Numerical answer
Show answer
Answer: 82
Q312021 · 26 Feb 2021 · Shift 2
1. A.
2. B.
3. C.
4. D.
Show answer
Answer: A
Q342021 · 26 Feb 2021 · Shift 2
A scooter accelerates from rest for time $t_{1}$ at constant rate $a_{1}$ and then retards at constant rate $a_{2}$ for time $t_{2}$ and comes to rest. The correct value of $\frac{t _{1}}{t _{2}}$ will be :
1. A. $\frac{a _{1} + a _{2}}{a _{2}}$
2. B. $\frac{a _{1} + a _{2}}{a _{1}}$
3. C. $\frac{a _{2}}{a _{1}}$
4. D. $\frac{a _{1}}{a _{2}}$
Show answer
Answer: C
Q412021 · 26 Feb 2021 · Shift 2
The length of metallic wire is $l_{1}$ when tension in it is $T_{1}$ . It is $l_{2}$ when the tension is $T_{2}$ . The original length of the wire will be :
1. A. $\frac{T _{1} l _{1} - T _{2} l _{2}}{T _{2} - T _{1}}$
2. B. $\frac{l _{1} + l _{2}}{2}$
3. C. $\frac{T _{2} l _{1} + T _{1} l _{2}}{T _{1} + T _{2}}$
4. D. $\frac{T _{2} l _{1} - T _{1} l _{2}}{T _{2} - T _{1}}$
Show answer
Answer: D
Q552021 · 26 Feb 2021 · Shift 2· Numerical answer
The volume V of a given mass of monoatomic gas changes with temperature T according to the relation $V = K T^{\frac{2}{3}}$ . The workdone when temperature changes by 90K will be xR. The value of x is _________. [R = universal gas constant]
Show answer
Answer: 60
Q582021 · 26 Feb 2021 · Shift 2· Numerical answer
Show answer
Answer: 4
Q412021 · 25 Feb 2021 · Shift 2
The wavelength of the photon emitted by a hydrogen atom when an electron makes a transition from n = 2 to n = 1 state is :
1. A.194.8 nm
2. B.490.7 nm
3. C.913.3 nm
4. D.121.8 nm
Show answer
Answer: D
Q482021 · 25 Feb 2021 · Shift 2
A stone is dropped from the top of a building. When it crosses a point 5 m below the top, another stone starts to fall from a point 25 m below the top. Both stones reach the bottom of building simultaneously. The height of the building is :
1. A.50 m
2. B.25 m
3. C.45 m
4. D.35 m
Show answer
Answer: C