Light: Mixing Primary, Secondary and Complementary Colours

There are two nice links below which show how light beams are mixed.

http://mc2.cchem.berkeley.edu/Java/RGB/example1.html
This link shows how varying the intensity of the primary colours, can lead to the creation of all colours. Your standard CRT TV uses this type of "colour mixing" to achieve the colours of the images on the screen.

http://www.hal-pc.org/~clement/Simulations/Mixing%20Colors/rgbColor.html
This is an excellent applet to show the mixing of the 3 Primary Colours (Red, Blue and Green). It also shows very clearly the "Secondary Colours" and makes the "Complimentary Colours" very easy to identify.