Radio frequencies are measured in which unit?

Radio frequencies are measured in Hertz. This unit quantifies the number of cycles per second of a periodic wave, which is fundamental to understanding radio frequency signals. For example, if a radio frequency is said to be 100 MHz, this means the wave oscillates 100 million times per second.

The other units mentioned have different applications: Decibels is a logarithmic unit used to express the ratio of power levels or intensities, particularly in the context of signal strength and sound; Volts measure electrical potential difference; and Amperes measure the flow of electric current. These units, while important in the field of electronics and communication, do not apply to the measurement of frequency. Thus, Hertz is specifically designated for frequency, making it the correct choice for the question.