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Light

(Science: microscopy) light is radiant energy of such wavelength that, falling on the retina, it stimulates the rods and cones of the eye and produces the sensation of vision. The foregoing is a physiological (subjective) definition which tells what light does, under certain conditions, rather than what it is. According to the (objective) Maxwell theory, all radiant energy is electromagnetic in character, the generation of the radiation depending upon the portion of the spectrum under consideration. For that part of the spectrum lying within the visual range, approximately 400 to 700 nanometres (nm) the release of light energy from externally stimulated sources may be thought of as due to atomic or molecular vibration or to the passing of electrons from high to lower energy levels accompanied by the spasmodic release of energy as the electronic orbits decrease in diameter.

See: quantum theory. Any device serving as a source of illumination; he stopped the car and turned off the lights.The quality of being luminous; emitting or reflecting light; its luminosity is measured relative to that of our sun.The visual effect of illumination on objects or scenes as created in pictures; he could paint the lightest light and the darkest dark.Make lighter or brighter; This lamp lightens the room a bit.(physics) electromagnetic radiation that can produce a visual sensation; the light was filtered through a soft glass window.The part of the electromagnetic spectrum visible to the eye. This varies between blue at 400 nanometres and red at 770 nanometres.