Question

State the conditions required for total internal reflection of light to take place.

Answer 1

There are two conditions for total internal reflection of light to take place :

(1) Light has to travel from denser medium to rarer medium but not vice-versa.

(2) Critical angle of the medium ${\theta }_c={\sin }^{-1}(\frac{n_{rarer}}{n_{denser}})$

where $n$ is the refractive index.

Angle of incidence $\theta$ must be greater than the critical angle of medium ${\theta }_c$.