Question

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 is a stereo system
(d) sound energy into electrical energy in public address system

Answer 1

A microphone converts sound energy into electrical energy in public address systems.
Therefore, the answer is,
(d) Sound energy into electrical energy in public address system.