State the energy changes in the following while in use:

(a) An electric bulb

(b) An electric oven

(c) A loudspeaker

(d) A microphone

(e) An electric motor

(f) A wind mill

State two factors on which the potential energy of a body at a certain height above the ground depends.

A body of mass m is moved from ground to a height h. If force of gravity on mass of 1 kg is g newton, find:

(a) the force needed to lift the body,

(b) the work done in lifting the body and

(c) the potential energy stored in the body.

Can a body possess energy even when it is not in motion? Explain your answer with an example.