What term is used to refer to the number of oscillations a wave undergoes in a certain amount of time?

The term that refers to the number of oscillations a wave undergoes in a certain amount of time is frequency. Frequency measures how often a wave completes a cycle in one second and is typically expressed in hertz (Hz). For example, a wave with a frequency of 10 Hz oscillates 10 times in one second. This concept is crucial in various fields like physics and music, as it relates to sound waves and light waves, influencing characteristics like pitch and color.

In contrast, wavelength refers to the physical distance between consecutive peaks of a wave and is unrelated to the rate of oscillation. Amplitude refers to the height of the wave, indicating how much energy the wave carries, but it doesn't indicate how often the oscillations occur. Reflection pertains to the bouncing back of waves when they encounter a barrier, which is also not related to the frequency of oscillation. Thus, frequency is the term that accurately encompasses the idea of the number of oscillations occurring over a set period.