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

`A=r+0impliesr=30^(@)`
From Snell's law at surface `AB`
`mu=(sin i)/(sin i)`
`=sqrt(2)=(sin i)/(sin 30^(@))impliesi=45^(@)`