Which of the following is NOT a component of a radio system?

The correct answer is a battery, as it is not a primary component of a radio system itself. A radio system fundamentally consists of a transmitter, receiver, and antenna, which are essential for the operation of telecommunications.

The transmitter converts information into a radio signal, the receiver picks up the transmitted signals and converts them back into usable information, and the antenna facilitates the actual transmission and reception of radio waves. While a battery may provide power for these components, it does not directly participate in the fundamental radio system function of transmitting and receiving signals. Therefore, it is classified as an ancillary component rather than a core part of the radio system.

This distinction highlights the role of the battery as a power source rather than an integral part of the signal transmission process.