Wavelength, defined for a periodic motion, means the distance during one period. For visible light and UV-radiation, wavelength are usually given in Ângstrˆms. (1 ≈ = 0.1 nm. 1nm = one billionth of a metre. The wavelength of visible light ranges from 4000 to 7000 ≈.
A human sees the different wavelengths of the light as different colours. Ultraviolet radiation has somewhat shorter wavelengths (100-4000 ≈). The wavelengths of X radiation are even shorter (0.1-100 ≈), and the wavelengths of gamma radiation are below 0.1 ≈.
Infrared radiation ranges from the upper end of visible light up to a few millimetres wavelength. Radio waves are also electromagnetic radiation, with even longer wavelengths.
The wavelength, (lambda), is obtained by dividing the propagation speed of the motion by the frequency of the motion.
