Question

A prism of glass of index of refraction 1.50 has angle of 45,45,90. A ray of light is incident on one of the short faces at an angle of theta. What is the maximum value of theta for which the ray of light suffer total internal reflection at the long face?

Answer 1

i know that the two angles inside the prism are sum to 45 degrees.

Answer 2

n(air)sin(theta)=n(glass)sin(b)
and
n(glass)sin(c)=n(air)sin(90)-for reflection
also
b+c=45
not sure how to continue....

Answer 3

sin(theta)=cos(b)-sqrt(2)
but its not a final answer