Question:
A light ray falling at an angle of $45^{\circ}$ with the surface of a clean slab of ice of thickness $1 \mathrm{~m}$ is refracted into it at an angle of $30^{\circ}$. Calculate the time taken by the light rays to cross the slab. Speed of light in vacuum $=3^{*} 10^{6} \mathrm{~m} / \mathrm{s}$.
Solution:
