A ray of light falls on the surface of a spherical paper weight making an angle $i$ with the normal

Question

A ray of light falls on the surface of a spherical paper weight making an angle $i$ with the normal and is refracted in the medium at an angle $r$. The angle of deviation of the emergent ray from the direction of the incident ray is\

Professor PC Thomas Classes · Answer

Deviation at the first face $=\mathrm{i}-\mathrm{r}$\ Deviation at the second face $=\mathrm{i}-\mathrm{r}$\ in the same direction.\ $	herefore$ Total deviation $=$\