Determine the velocity of a particular wave. The velocity of a majority of waves through a particular medium has been identified or described in literature. Therefore, identifying the specific type of wave and the medium through which it is traveling allows for the identification of the velocity. For example, the speed of sound in air has been established as approximately 343 meters per second (m/s).
Determine the frequency of the wave. The frequency is the number of complete wave intervals that occur per unit time and is normally expressed in Hertz (Hz). The frequency of a wave has an inverse relationship with the wavelength, meaning a smaller wavelength results in a greater frequency. Using the sound wave example, the human ear can identify sound waves in the frequency range of 20-20,000 Hz.
Use the velocity and frequency of the wave to determine the wavelength. The wavelength can be calculated by dividing the velocity of the wave by the frequency (wavelength = velocity / frequency). Using the sound example, a sound wave with a frequency of 250 Hz has a wavelength of 1.4 meters. Wavelength = (343 m/s) / 250 Hz.