Which unit is used to measure frequency?

The unit used to measure frequency is Hertz (Hz). Frequency quantifies how often a periodic event occurs in a given timeframe, specifically representing the number of cycles per second. In electrical engineering and physics, this measurement is crucial for understanding phenomena such as wavelength in electromagnetic waves, sound waves, and alternating current.

A Hertz is defined as one cycle per second, making it a foundational unit in various fields, including telecommunications, audio processing, and signal analysis. It’s particularly important in contexts such as radio broadcasting, where frequencies are measured in kilohertz (kHz) or megahertz (MHz) depending on the scale.

The other options represent units that measure different physical quantities: Joules measure energy, Volts measure electric potential, and Watts measure power. Each of these plays a vital role in their respective contexts but does not relate to the concept of frequency. Therefore, Hertz stands out as the correct unit for measuring how frequently an event occurs over time.