What is the Light ?
Light is an electromagnetic (later referred as EM) radiation with a wavelength that is visible to the eye. The visible spectrum is the portion of the EM spectrum that is visible to (can be detected by) the human eye. EM radiation in this range of wavelengths is called visible light or simply light. There are no exact bounds to the visible spectrum; a typical human eye will respond to wavelengths in air from 400 to 700 nm, from infra red to ultra violet range.

Visible EM spectrum

The combination of these EM waves produces white light, which is what we see from the Sun and from most artificial light sources.