What is Light?

Light is energy! It is energy in the form of electro-magnetic radiation in waves.

The visible light spectrum spans from approximately 770nm to 380nm with the long wavelengths at the red end of the spectrum and the short wavelengths at the blue end.

           Fig. 1

White light has an even representation of all colours in the spectrum i.e. all wavelengths represents an equal amount of energy.

This spectrum is true for the sunlight but artificial light sources such as electrical lamps typically have a differently composed spectrum.

Standard light bulbs with incandescent (i.e. glowing) elements have a spectrum with a bias to the red end of the spectrum, wh