Question

Show that for a material with refractive index μ ≥ √2 , light incident at any angle shall be guided along a length perpendicular to the incident face.

Answer 1

Any ray entering at an angle i shall be guided along AC if the angle the ray makes with the face AC ( ϕ ) is greater than the critical angle.

The smallest angle f shall be when i =π/2. If that is greater than the critical angle then all other angles of incidence shall be more than the critical angle.