A ray of light passing through a prism having refractive index $\sqrt{2}$ suffers minimum deviation. It is found that the angle of incidence is double the angle of refraction within the prism. Then angle of prism is,

A small bulb is placed at the bottom of a tank containing water to a depth of$80 \mathrm{cm}$. What is the area of the surface of water through which light from the bulb can emerge out? The refractive index of water is$1.33\text{.}$ (Consider the bulb to be a point source.)

$\sin \left(49°\right)=\frac{1}{1.33}$ and $\tan \left(49°\right)=1.15$

In the given figure, the principal section of a glass prism is an isosceles triangle$\mathrm{ABC}$ with $AB=AC$ . The face $AC$ is silvered. A ray incident normally on face $AB\text{,}$ after two reflections emerges from the base$\mathrm{BC}$ in a direction perpendicular to it. What is the angle$\angle BAC$ of a prism?