👉 Wavelength, also known as wave length or wave number, is a measure of how far two waves can travel in a given time. It is defined as the distance between two identical points on one wavefront compared to another, which are separated by the same distance. In other words, it's the distance between two frequencies (or amplitudes) that occur at the same point in a sound or light wave. Wavelengths can be measured using various units such as meters (m), cent