Question

If a light ray is exiting diamond into vacuum, what is the maximum angle of incidence which will allow light to be transmitted?

Answer 1

We have to find the critical angle; it is the largest angle of incidence for which refraction can still occur. For any angle of incidence greater than the critical angle, light will undergo total internal reflection and no transmission occur.

Using snell's law for refraction for critical angle :

  

for

puth this in above equation, we will get

n for diamond = 1.42 and n for vacuum = 1

on sloving

this is the maximum allowed incident angle for transmission of light