Question

Derive the relation between refractive index of a medium and its critical angle.

Answer 1

✔When the angle of incidence is equal to the critical angle, the angle of refraction is equal to 90°. ... light is travelling from an optically denser medium (higher refractive index) to an optically less dense medium (lower refractive index). the angle of incidence is greater than the critical angle.

Answer 2

When the angle of incidence is equal to the critical angle, the angle of refraction is equal to 90°. If the angle of incidence is bigger than this critical angle, the refracted ray will not emerge from the medium, but will be reflected back into the medium. This is called total internal reflection.