Energy

Q.

The capacity of a body to do work is called its______.

Q.

Name the phenomenon on the basis of which electric generator works.

Q. A wind - powered generator converts wind energy into electrical energy. Assume that the generator converts a fixed fraction of the wind energy intercepted by its blades into electrical energy. For wind speed V, the electrical power output will be proportional to

1. $V$
2. $V^2$
3. $V^3$
4. $V^4$

Q. Two unequal masses are tied together with a cord with a compressed spring in between.
Which one is correct ?

1. Both mases will have equal KE.
2. Lighter block will have greater KE.
3. Heavier block will have greater KE.
4. None of above answer is correct

Q. Capacity to do work is called energy.

1. False
2. True

Q.

The intensity of sound from a point source is $1.0\times {10}^{-6}{m}^{-2}$ at a distance of 5.0 m from the source. What will be the intensity at a distance of 25 m from the source?

1. $0.06\times {10}^{-8}W{m}^{-2}$

2. $0.08\times {10}^{-8}W{m}^{-2}$

3. $1\times {10}^{-8}W{m}^{-2}$

4. $0.04\times {10}^{-8}W{m}^{-2}$

Q.

A spinning wheel A is brought in contact with another wheel B which is initially at rest. Because of the friction at contact, the second wheel also starts spinning, then which of the following energies of B won't change?

1. Kinetic

2. Potential

3. Mechanical

4. Internal

Q. A $2\text{g}$ bullet moving with a speed of $210\text{m/s}$ brought to a sudden stoppage by an obstacle. The total heat produced goes to the bullet. If the specific heat of the bullet is $0.03{\text{cal/g}}^{\circ }\text{C}$ the rise in its temperature will be

1. ${175}^{\circ }\text{C}$
2. ${180}^{\circ }\text{C}$
3. ${150}^{\circ }\text{C}$
4. ${125}^{\circ }\text{C}$

Q. An ideal massless spring $S$ can be compressed by $1m$ by a force of $100N$ in equilibrium. The same spring is placed at the bottom of a frictionless inclined plane at ${30}^{\circ }$ to the horizontal. A $10kg$ block $M$ is released from rest at the top of the incline and is brought to rest momentarily after compressing the spring by $2m$. If $g=10m/s^2$, what is the speed of mass just before it touches the spring?

1. $\sqrt{20}m/s$
2. $\sqrt{30}m/s$
3. $\sqrt{10}m/s$
4. $\sqrt{40}m/s$

Q.

Ability to do work is called…….