A transparent solid cylindrical rod has a refractive index of `(2)/(sqrt3)`. It is surrounded by air. A light ray is incident at the mid point of one end of the rod as shown in the figure.
The incident angle `theta` for which the light ray grazes along the wall of the rod is

Options

A. `sin^(-1)((sqrt3)/(2))`
B. `sin^(-1)((2)/(sqrt3))`
C. `sin^(-1)((1)/(sqrt3))`
D. `sin^(-1)((1)/(2))`

Answer

D

Explanation

`sin theta=(2)/(sqrt3) sin r =(2)/(sqrt3) cos i` …….`(i)`
and `(2)/(sqrt3) sini = sin 90^(@) rArr i=60^(@)` ………`(ii)`
Form `(i)` and `(ii)` `sin theta=(1)/(sqrt3)`