Rays of light beam through the trees on a cool morning.A
First thing we can say about light is that it is something that enables us to see. But what is light? We know that during the day the primary source of the light is the sun, and the secondary source is the brightness of the sky. Other common sources are flames, white–hot filaments in light bulbs and glowing gas in glass tubes. Light is a form of energy, which enables us to see objects from which it comes. We detect light by our eye, which is an optical instrument provided to us by nature. Light can be transmitted from one place to another at finite velocity.
Light energy originates somewhere within an atom and ends its existence, when it enters another atom or molecule. All light originates from the accelerated motion of electric charges. Light is an electromagnetic phenomenon; visible light is a tiny part of a larger electromagnetic spectrum of radiation ranging from cosmic rays to radio waves. Understanding the nature of light, the emission and absorption processes are very important.