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
- AZero
- ✓$\alpha$
- C$\sin ^{-1}(1 / n)$
- D$2 \sin ^{-1}(1 / n)$
