What term describes the number of wave crests that pass a fixed point during a particular period of time?

The term that describes the number of wave crests that pass a fixed point during a specific period of time is frequency. Frequency measures how often a repeating event occurs in a given timeframe, typically expressed in Hertz (Hz), which represents cycles per second. In the context of waves, this means that if you count the number of times a wave crest arrives at a point in one second, you are measuring the frequency of that wave.

For example, if a wave completes 5 cycles in one second, its frequency would be 5 Hz. Understanding frequency is crucial in various fields, including physics, sound, and telecommunications, as it relates directly to the perception of sound pitch and the behavior of electromagnetic waves.

The other terms relate to different properties of waves: amplitude refers to the height of the wave crest, wavelength is the distance between successive wave crests, and velocity pertains to the speed at which the wave travels through a medium. Each of these properties contributes to the overall behavior of waves but does not define the rate at which crests pass a fixed point.