What is the definition of wavelength?

Wavelength is defined as the shortest distance between equivalent points on a wave. This means it refers to the distance over which the wave's shape repeats. For instance, if you consider a sinusoidal wave, the wavelength would be the distance from one peak to the next peak or from one trough to the next trough. This measurement is fundamental in understanding wave properties, as it directly influences the wave's energy, frequency, and speed.

In wave mechanics, knowing the wavelength allows for further calculations regarding the wave's behavior, such as its frequency (the number of wavelengths that pass a point in one second) and speed (calculated as the product of frequency and wavelength). The other concepts listed, like amplitude (the height of the wave), wave speed (how fast the wave travels), or energy (associated with the wave's amplitude and frequency), are distinct properties that do not define wavelength.