These Objective Questions on Work, Energy and Power (Class XI, Physics) will help you in preparing for different examinations like AIEEE, AIPMT, IIT, and other +2 level competitive exams, and will also help in many government exams that ask the basics of physics.
1. When the momentum of a body increases by 200%, its KE increases by how much percent ?
2. Two bodies of masses m1 and m2 are moving with same kinetic energy. If P1 and P2 are their respective momentum, the ratio P1 P2 is equal to –
3. KE acquired by a mass m in travelling a certain distance d, starting from rest, under the action of a constant force F is ?
- Directly proportional to m
- Directly proportional to √m
- Directly proportional to 1/m
- None of these
4. A simple pendulum with the bob of mass m and length x is held in position at an angle θ1 and then angle θ2 with the vertical. When released from these positions, speeds with which it passes the lowest positions are v1 & v2 respectively. Then, v1/v2 is
- 1-cos θ1/1-cos θ2
- sqrt(1-cos θ1/1-cos θ2)
- sqrt(2gx(1-cos θ1)/1-cos θ2)
- sqrt((1-cos θ1)/2gx(1-cos θ2))
5. A U–238 nucleus originally at rest, decays by emitting a α-particle, say with a velocity of v m/s. The recoil velocity (in m/s) of the residual nucleus is ?
6. The total work done on a particle is equal to the change in its kinetic energy. This is applicable –
- Only if the conservative forces are acting on it
- Only in inertial frames
- Only when pseudo forces are absent
7. Potential energy is defined –
- Only in conservative fields
- As the negative of work done by conservative forces
- As the negative of work done by external forces when ΔK = 0
- All of these
8. A spring with spring constants ‘k’ when compressed by 1 cm, the potential energy stored is U. If it is further compressed by 3 cm, then the change in its potential energy is ?
9. Two springs have force constant K1 and K2 (K1 > K2). Each spring is extended by same force F. If their elastic potential energy are E1 and E2 then E1/E2 is ?
- K1 / K2
- K2 / K1
- √(K2 / K1)
- √(K1 / K2)
10. An unloaded bus can be stopped by applying brakes on a straight road after covering a distance x. Suppose, the passenger add 50% of its weight as the load and the braking force remains unchanged, how far will the bus go after the application of the brakes ? (Velocity of bus in both cases is same)
11. Initially, mass m is held such that spring is in a relaxed condition. If mass m is suddenly released, maximum elongation in the spring will be ?
- mg / k
12. The power of water pump is 4 kW. If g = 10 m/s2, the amount of water it can raise in 1 minute to a height of 20 m is (1 litre = 1Kg)
- 100 litre
- 1000 litre
- 1200 litre
- 2000 litre