Which of the following is a transducer in communication system.

The correct answer is Option (2) → Speaker

In a communication system a transducer is any device that converts one form of energy into another. A microphone changes sound into an electrical signal at the sending end; a speaker does the reverse at the receiving end, turning the electrical signal back into sound. So the speaker is a transducer.

An amplifier, a transmitter and a modulator all work on a signal that is already electrical: they strengthen it, send it out, or superpose it on a carrier wave, but they do not change the form of energy.

Note: This question is from the pre-rationalised NCERT book (2022-23). The topic was removed from the latest NCERT book (2026-27), and it also appears to be out of the CUET 2026 syllabus.

NCERT (Pre-rationalised edition, 2022-23):
Basic Terminology Used in Electronic Communication Systems – “… (i) Transducer: Any device that converts one form of energy into another can be termed as a transducer.”