A device that converts energy from one form to another.

• A. Transducer
• B. Transformer
• C. Rectifier
• D. Generator

Answer: (A)

A transducer is any device that changes energy from one form to another. That broad idea covers many common parts: a microphone turns sound waves (mechanical energy in the air) into an electrical signal, a speaker does the opposite, a photovoltaic cell converts light into electrical energy, and a thermocouple converts heat into electrical voltage. The other options are more specific or stay within the same energy form. A transformer moves electrical energy from one voltage level to another without changing the energy’s form, just how it’s carried. A rectifier changes AC to DC, still electrical energy. A generator does convert mechanical energy into electrical energy, which is indeed energy conversion, but transducer is the general term for devices that convert energy from one form to another, making it the best fit here.