There is a fixed relationship between the frequency and the wavelength, which is the distance between identical points on two adjacent waves (Figure 1.1), of any type of wave: sound (pressure), electromagnetic (radio) and light. The type of wave and the speed at which the wavefront travels through the medium determines the relationship. The speed of propagation is slower in higher density media.
Wavelength (l) (metres)Sound waves travel more slowly than radio and light waves which, in free space, travel at the same speed, approximately 3× 108 metres per second, and the relationship between the frequency and wavelength of a radio wave is given by:
λ=
3× 108f metres where λ is the wavelength and f is the frequency in hertz (Hz).