In order of wavelength, smallest first, the electromagnetic spectrum goes like this:
'�-rays, X-rays, ultraviolet,
visible light, infrared, TV, and then various radio waves.
For colours, the only part of the electromagnetic spectrum visible to humans is the ROYGBV part, ranging from violet (about 400nm / 7.5'~10
14Hz) to red (about 760nm / 3.9'~10
14Hz). If you would like to look up the colour of a certain frequency of light, there are loads of web sites that do that.
http://www.csun.edu/~hchum001/bookcase/images/spec
trum.gif.
Apparently snakes can see part of the infrared section of light - the kind of radiation emitted by all objects as heat - but I don't know how they would describe the colour!
As for what radiation is, I've only just started learning that, but if light is considered to travel as particles, each particle of light has energy
hf, where
h is the Planck constant 6.63'~10
-34Js and
f is the frequency.
I hope this helps.