Which device is used for radiating and receiving electromagnetic energy?

• A. Transmitter
• B. Receiver
• C. Antenna
• D. Amplifier

Answer: (C)

An antenna is the component that interfaces between electrical signals and free-space electromagnetic waves. It converts the electrical energy from the transmitter into radio waves to radiate, and it also converts incoming radio waves back into electrical signals for the receiver to process. This dual capability comes from reciprocity—the same structure that emits waves is effective at receiving them as well.

A transmitter is responsible for creating and sending the signal, but it doesn’t receive. A receiver picks up signals but doesn’t emit. An amplifier increases the strength of a signal but doesn’t by itself radiate or receive electromagnetic energy. Thus, the antenna is the device that both radiates and receives EM energy.