MCQ
A diverging beam of light from a point source $S $ having divergence 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
- A$Zero$
- ✓$\alpha$
- C${\sin ^{ - 1}}(1/n)$
- D$2\,{\sin ^{ - 1}}(1/n)$
