A microphone converts:

A. Electrical energy into sound energy in ordinary telephone

B. Microwave energy into sound energy in a mobile phone

C. Sound energy into mechanical energy in a stereo system

D. Sound energy into electrical energy in public address system

How much energy does a 100 W electric bulb transfer in 1 minute?

A. 100 J B. 600 J

C. 3600 J D. 6000 J

The device which converts mechanical energy into energy which runs our microwave oven is:

A. Electric motor

B. Alternator

C. Turbine

D. Electric heater

The following data was obtained for a body of mass 1 kg dropped from a height of 5 metres:

Distance above ground Velocity

5 m/s 0 m/s

3.2 m 6 m/s

0 m 10 m/s

Show by calculations that the above data verifies the law of conservation of energy (Neglect air resistance). (g = 10 m/s²)

A ball falls to the ground as show2n below:

A potential energy = 80 J

Kinetic energy = 0

B Kinetic energy = 48 J

C = potential energy = 0

(a) What is the kinetic energy of ball when it hits the ground?

(b) What is the potential energy of ball at B?

(c) Which law you have made use of in answering this question?