Question

Explain the phenomenon of total internal reflection of light with an example.

Answer 1

Step 1: Explanation of Total Internal Reflection:

Total internal reflection of light refers to the phenomenon which occurs when the light rays travel from a more optically denser medium to a less optically denser medium and are incident at an angle greater than the critical angle for the two media and the ray totally reflects into the medium, obeying the laws of reflection.

The formula for total internal reflection

$\sin {\theta }_c=\frac{n_2}{n_1}$

where ${\theta }_c$ is the critical angle for total internal reflection,

$n_1$ and $n_2$ are the refractive indices of the two media.

Step 2: Conditions of Total Internal Reflection:

1. The angle of incidence must be greater than the critical angle.
2. The light ray moves from a more dense medium to a less dense medium.

Step 3: Example of Total Internal Reflection:

1. The formation of Mirage. It is caused due to total internal reflection of light by the various layers of air due to very hot weather.