Work, Energy & Power · JEE Main previous year questions

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2023 19 questions

Q312023 · 13 Apr 2023 · Shift 1
1. A.
2. B.
3. C.
4. D.
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Answer: A
Q592023 · 13 Apr 2023 · Shift 1· Numerical answer
The elastic potential energy stored in a steel wire of length $20 m$ stretched through $2 cm$ is $80 J$ . The cross sectional area of the wire is __________ $mm^{2}$ . ( Given, $Y = 2.0 \times 1 0^{11} Nm^{- 2}$ )
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Answer: 40
Q472023 · 13 Apr 2023 · Shift 2
A particle executes SHM of amplitude A. The distance from the mean position when its kinetic energy becomes equal to its potential energy is :
1. A. $\frac{1}{2} A$
2. B. $\frac{1}{2} A$
3. C. $2 A$
4. D. $2 A$
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Answer: A
Q322023 · 12 Apr 2023 · Shift 1
Given below are two statements: Statement I : A truck and a car moving with same kinetic energy are brought to rest by applying brakes which provide equal retarding forces. Both come to rest in equal distance. Statement II : A car moving towards east takes a turn and moves towards north, the speed remains unchanged. The acceleration of the car is zero. In the light of given statements, choose the most appropriate answer from the options given below
1. A.Statement I is incorrect but Statement II is correct.
2. B.Statement I is correct but Statement II is incorrect.
3. C.Both Statement I and Statement II are correct.
4. D.Both Statement I and Statement II are incorrect.
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Answer: B
Q342023 · 8 Apr 2023 · Shift 2
In photo electric effect A. The photocurrent is proportional to the intensity of the incident radiation B. Maximum Kinetic energy with which photoelectrons are emitted depends on the intensity of incident light. C. Max. K.E with which photoelectrons are emitted depends on the frequency of incident light. D. The emission of photoelectrons require a minimum threshold intensity of incident radiation. E. Max. K.E of the photoelectrons is independent of the frequency of the incident light. Choose the correct answer from the options given below:
1. A.A and E only
2. B.A and B only
3. C.B and C only
4. D.A and C only
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Answer: D
Q432023 · 8 Apr 2023 · Shift 2
The temperature at which the kinetic energy of oxygen molecules becomes double than its value at $2 7^{\circ} C$ is
1. A. $62 7^{\circ} C$
2. B. $92 7^{\circ} C$
3. C. $32 7^{\circ} C$
4. D. $122 7^{\circ} C$
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Answer: C
Q482023 · 6 Apr 2023 · Shift 1
The number of air molecules per $cm^{3}$ increased from $3 \times 1 0^{19}$ to $12 \times 1 0^{19}$ . The ratio of collision frequency of air molecules before and after the increase in number respectively is:
1. A.1.25
2. B.0.25
3. C.0.50
4. D.0.75
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Answer: B
Q542023 · 6 Apr 2023 · Shift 2· Numerical answer
A body is dropped on ground from a height ' $h_{1}$ ' and after hitting the ground, it rebounds to a height ' $h_{2}$ '. If the ratio of velocities of the body just before and after hitting ground is $4$ , then percentage loss in kinetic energy of the body is $\frac{x}{4}$ . The value of $x$ is ___________.
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Answer: 375
Q482023 · 1 Feb 2023 · Shift 1
The average kinetic energy of a molecule of the gas is
1. A.proportional to volume
2. B.dependent on the nature of the gas
3. C.proportional to absolute temperature
4. D.proportional to pressure
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Answer: C
Q582023 · 1 Feb 2023 · Shift 1· Numerical answer
The amplitude of a particle executing SHM is $3 cm$ . The displacement at which its kinetic energy will be $25%$ more than the potential energy is: ________ $cm$
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Answer: 2
Q552023 · 31 Jan 2023 · Shift 1· Numerical answer
A solid sphere of mass $1 kg$ rolls without slipping on a plane surface. Its kinetic energy is $7 \times 1 0^{- 3} J$ . The speed of the centre of mass of the sphere is ___________ $cm s^{- 1}$
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Answer: 10
Q582023 · 31 Jan 2023 · Shift 2· Numerical answer
A ball is dropped from a height of $20 m$ . If the coefficient of restitution for the collision between ball and floor is $0.5$ , after hitting the floor, the ball rebounds to a height of ___________ m.
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Answer: 5
Q472023 · 30 Jan 2023 · Shift 1
A ball of mass $200 g$ rests on a vertical post of height $20 m$ . A bullet of mass $10 g$ , travelling in horizontal direction, hits the centre of the ball. After collision both travels independently. The ball hits the ground at a distance $30 m$ and the bullet at a distance of $120 m$ from the foot of the post. The value of initial velocity of the bullet will be (if $g = 10 m/s^{2}$ ) :
1. A. $120 m/s$
2. B. $360 m/s$
3. C. $400 m/s$
4. D. $60 m/s$
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Answer: B
Q372023 · 29 Jan 2023 · Shift 1
A stone is projected at angle $3 0^{\circ}$ to the horizontal. The ratio of kinetic energy of the stone at point of projection to its kinetic energy at the highest point of flight will be -
1. A.1 : 4
2. B.1 : 2
3. C.4 : 3
4. D.4 : 1
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Answer: C
Q562023 · 29 Jan 2023 · Shift 1· Numerical answer
A 0.4 kg mass takes 8s to reach ground when dropped from a certain height 'P' above surface of earth. The loss of potential energy in the last second of fall is ____ J. (Take $g = 10 m/ s^{2}$ )
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Answer: 300
Q532023 · 25 Jan 2023 · Shift 1· Numerical answer
An object of mass 'm' initially at rest on a smooth horizontal plane starts moving under the action of force F = 2N. In the process of its linear motion, the angle $θ$ (as shown in figure) between the direction of force and horizontal varies as $θ = k x$ , where k is a constant and $x$ is the distance covered by the object from its initial position. The expression of kinetic energy of the object will be $E = \frac{n}{k} sin θ$ . The value of n is ____.
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Answer: 2
Q462023 · 25 Jan 2023 · Shift 2
A body of mass m is taken from earth surface to the height h equal to twice the radius of earth $(R_{e})$ , the increase in potential energy will be : (g = acceleration due to gravity on the surface of Earth)
1. A. $\frac{1}{2} m g R_{e}$
2. B. $3 m g R_{e}$
3. C. $\frac{1}{3} m g R_{e}$
4. D. $\frac{2}{3} m g R_{e}$
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Answer: D
Q572023 · 25 Jan 2023 · Shift 2· Numerical answer
A body of mass 1 kg collides head on elastically with a stationary body of mass 3 kg. After collision, the smaller body reverses its direction of motion and moves with a speed of 2 m/s. The initial speed of the smaller body before collision is ____ $m s^{- 1}$ .
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Answer: 4
Q582023 · 24 Jan 2023 · Shift 1· Numerical answer
A spherical body of mass $2 kg$ starting from rest acquires a kinetic energy of $10000 J$ at the end of $5^{th}$ second. The force acted on the body is ____ $N$ .
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Answer: 40