How is wavelength defined?

Wavelength is specifically defined as the distance between successive peaks (or any equivalent points) of a wave. This means that it represents the spatial period of the wave, marking the length of one complete cycle as it propagates through space. By measuring the distance from one peak to the next, you can determine the wavelength.

Option C suggests measuring the wavelength from the beginning of a wave peak to the end of a wave valley, but this is not the standard definition of wavelength, which focuses solely on the distance between similar points on consecutive waves, like peaks or troughs.

Other options, while addressing aspects of wave behavior, don't correctly capture the definition of wavelength. For instance, the speed of the wave refers to how fast the wave moves through a medium, which is distinct from wavelength. Similarly, the length of a wave's cycle over time is related to the wave's frequency and speed, not the spatial measurement of wavelength itself. Understanding this definition is crucial, as it underpins many concepts in wave physics, including sound and light wave behavior.