At the border of two materials usually both reflection and
refraction appears
• In some peculiar situations however the refracted light is also
reflected! --> reflection is total OR no refracted ray!
• This can ONLY happen when light travels from a medium with
bigger index of refraction to one with a smaller index of
refraction, and the incident angle is big enough
• for high enough α1= α0 --> α2=900
• if α1> α0 :no refracted ray --> total reflection