Energy and its Sources

Q.

What are the three types of thermal energy?

Q.

Define transformation of energy.

Q.

Law of conservation of mechanical energy can be applied to a non-isolated system.

1. True
2. False

Q.

State the law of conservation of energy.

Q.

Comment: “Sun is the ultimate source of fossil fuels”.

Q.

Which is the ultimate source for generating electricity?

1. Sun

2. Bio mass

3. Nuclear energy

4. None of these

Q. We know that If a ball of mass 1 kg is kept at a height 10 m possess potential energy “mgh” i.e. $(1\times 10\times 10)=100$ J. (Taking earth surface as reference, where m = mass of object, g = acceleration due to gravity, h = height of object from earth surface.) what will be the kinetic energy of the ball when the ball is allowed to freely fall from a height 10m from the surface of earth and it hits the ground? (take g = 10 $m/s^2$ and neglect air drag)

1. 100 J
2. 50 J
3. 10 J
4. 0 J