Question

The ‘information source’, whose ‘message signal’ needs to be transmitted is (i) a picture (ii) a (audio) musical composition and (iii) a ‘pressure variation’. The transducers, likely to be used in the three cases, would be (respectively): 

(1) based on photoelectric effect, based on piezoelectric effect and a microphone.

(2) based on piezoelectric effect, microphone and based on photoelectric effect. 

(3) based on photoelectric effect; a microphone and based on piezoelectric effect. 

(4) based on magneto–restriction effect; a microphone and based on photoelectric effect. 

Answer 1

Correct option : (3)

Explanation: 

A transducer is (usually) a device/setup that converts variations in a given physical variable into their corresponding electrical variations. It thus ‘readies’ the message signal for transmission over large distances. 

For ‘picture’ (variations in light intensity) the relevant transducer is based on the ‘photoelectric effect’. 

For audio musical compositions (variations in sound intensity) the relevant transducer is the microphone. For pressure variation relevant transducer is based on the phenomenon of ‘piezo electric effect’.