What is the correct term for the number of cycles of an electromagnetic wave that occur in one second?

The term that refers to the number of cycles of an electromagnetic wave that occur in one second is frequency. Frequency measures how often the wave oscillates or cycles in a given time period, specifically one second. It is typically expressed in hertz (Hz), where one hertz corresponds to one cycle per second. This concept is crucial in understanding various aspects of waves, including sound and light, as well as their interactions and behaviors.

Wavelength refers to the distance between successive crests or troughs of a wave and is not related to how frequently those waves occur. Amplitude measures the height or strength of the wave, indicating the intensity of the wave, rather than the rate at which cycles occur. The term "cycle" alone describes a single complete wave oscillation but does not quantify how many of those oscillations happen in a certain timeframe. Therefore, frequency is the appropriate term for quantifying the cycles per second of an electromagnetic wave.