Answer:
In a radio or television, the instrument that converts electrical energy into sound signals or image signals is called a transducer. Transducers are devices that can convert one form of energy into another.
In the context of television, a television camera is an example of a transducer that converts light energy (captured through a lens) into electrical signals representing images or video. These electrical signals can then be processed and transmitted for display on a television screen.
In the context of a radio, a microphone is an example of a transducer that converts sound waves (acoustic energy) into electrical signals. These electrical signals, which represent sound, can then be amplified, modulated, and broadcast over the radio waves for reception by a radio receiver.
So, depending on whether you're referring to a television or a radio, the specific transducer used for converting electrical energy to sound or image signals may vary, but the concept of a transducer applies to both.