Everything you have seen is based on some very simple formulae
But before I can explain those formulae I need to explain some names:


  • The 'normal' is the line which stands in a right-angle on the object that the light bundle hits.
  • The 'angle of impact' (geel) is the angle between the normal and the light bundle.
  • the 'refractive index' of an object gives info about how difficult it is for a light bundle to penetrate the object. The harder this is, the more the angle will move towards the normal. remark: the refractive index can never be smaller than 1

first law:
When a light bundle hits an object three things can happen:
  • All the light reflects
  • All the light goes through the object
  • Some light reflects and some light penetrates the object

second law:
When an incoming light bundle reflects off an object it always makes the same angle with the normal as the outgoing light bundle.


Third law: Snell's law
ni * sin(oi) = nt * sin(ot)
  • With ni the refractive index of the substance the incoming light bundle is in.
  • With nt the refractive index of the substance the outgoing light bundle is in.
  • With oi the angle of impact.
  • With ot the angle after impact.