We are capable of see visible light only in electromagnetic spectrum.
The list of visible lights are:
1) Violet
2) Indigo
3) Blue
4) Green
5) Yellow
6) Orange
7) Red
These are the Visible light which we can see easily.
But your question about which waves are shown on computer ? is that your question right, Than its right answer is, On computer there are basically three colours are used or waves are used to display any pictures or videos is Red, Green and Blue colours or waves.
Beacuse of these three basic colour combination we able to see many different colours on our computer screen.