What is the wavelength of a wave?

The wavelength of a wave is defined as the distance between two successive points that are in phase on the wave, typically measured from crest to crest or from trough to trough. This distance measures the length of one complete cycle of the wave, providing a critical parameter for understanding wave behavior and characteristics. Wavelength is a fundamental concept in wave physics, influencing properties such as frequency and speed.

The other choices focus on different aspects of wave behavior. The time for one complete cycle refers to the period, which is related to frequency but does not describe the spatial distance of the wave itself. The speed of the wave is the rate at which the wave travels through space, while the distance traveled in a second expresses how far the wave moves over time, neither of which captures the concept of wavelength directly. Therefore, identifying the distance between crests or troughs accurately defines the wavelength.