Angle of a prism is `30^(@)` and its refractive index is `sqrt(2)` and one of the surface is silvered. At what angle of incidence, a ray should be incident on one surface so that after reflection from the silvered surface, it retraces its path ?

Options

A. `30^(@)`
B. `60^(@)`
C. `45^(@)`
D. `sin^(-1) sqrt(1.5)`

Answer

C

Explanation

r = A = `30^(@)`
Snell.s law,
`n_(1) sin i= n_(2) `sin r
`rArr " " sin i= sqrt(2) sin 30^(@)`
`rArr i = 45^(@)`.