Visible Spectrum

We perceive electromagnetic energy having wavelengths in the range 400-700 nm as visible light.

Visible light is a very small part of electromagnetic energy : a narrow frequency band within the electromagnetic spectrum

• Red : 4.3 x 1014 HZ : 700nm        /      Violet : 7.5 x 1014 Hz : 400nm

• High frequencies Ultraviolet <=> High Energy ( E = h . n )

http://mo-www.harvard.edu/Java/MiniSpectroscopy.html

What we perceive as "light", or different colours, is a narrow frequency band within the electromagnetic spectrum.