A glass prism refracts light at each face, bending it toward the normal on the way in and away from the normal on the way out. White light is a mixture of every colour, so it fans into a spectrum, violet bending most and red least. A composite of three colours splits into just those three. Monochromatic light is light of a single colour (one wavelength), so it refracts at each face but does not split. Switch the source and watch.
MissionSend white light through the prism, then judge which colour bends the most.Streak 0Best 0
Single colour:
Which colour is bent the most by the prism?
prism angle60°
deviation of red (n = 1.513)38°
deviation of violet (n = 1.532)40°
violet has the higher index, so it bends more than red. On-screen spread is enlarged for clarity.