A diverging beam of light from a point source $S$ having divergence angle $α$ , 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 [2000]

Question

Smart Achievers · Accepted Answer

(2)

The incident and emergent rays $O A ∥ B C$ and $O D ∥ E F$ of a glass slab are parallel; therefore, the divergence angle remains the same.

Solution

1 zero

2 $α$

3 $\sin^{- 1} (\frac{1}{n})$

4 $2 \sin^{- 1} (\frac{1}{n})$

Ans.
(2)

The incident and emergent rays $O A ∥ B C$ and $O D ∥ E F$ of a glass slab are parallel; therefore, the divergence angle remains the same.

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