A diverging beam of light from a point source S having devergence angle `alpha`,
Channel: Doubtnut
Date: 2020-07-05

A diverging beam of light from a point source S having devergence angle `alpha`, falls symmetrically on a glass slab as shown. The angles of incidence of the two extreme rays are equal. If the thickness of the glass slab is t and the refractive index n, then the divergence angle of the emergent beam is