Light

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. 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). In physics, the term "light" may refer to the entire electromagnetic spectrum, which extends from radio waves and microwaves (long wavelengths) to X-rays and gamma rays (short wavelengths). The main source of light on Earth is the Sun. Light in Hebrew is אור (pronounced "or"). In other languages, light is known as Licht in German, Luz in Spanish, and Lumière in French.