Question

A ray of light incident normally on the face AB of the right-angled prism of refractive index of 1.5. The prism is partially immersed in a liquid of unknown refractive index. Find the value of refractive index of liquid so that the ray grazes along the side BC.

Answer 1

Here $i={60}^{\circ }$
From Snell's law, ${\mu }_{g}sini={\mu }_{l}sin{90}^{\circ }\Rightarrow 1.5sin{60}^{\circ }={\mu }_l$
$\therefore {\mu }_l=1.3$
So the refractive index of the liquid is 1.3.