Visible light" redirects here. For light that cannot be seen with
human eye, see Electromagnetic radiation. For other uses, see Light (disambiguation) and Visible light (disambiguation).
"Lightsource" redirects here. For the solar energy developer named Lightsource, see Lightsource Renewable Energy.
Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.
The word usually refers to visible light, which is the visible spectrum that is visible to the
human eye and is responsible for the sense of sight.1 Visible light is usually defined as having wavelengths in the
range of
400–700 nanometres (nm), or 4.00 × 10−7 to 7.00 × 10−7 m, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).
23 This wavelength means a frequency range of roughly 430–750 terahertz (THz).