A prism having refractive index `sqrt2` and refractive angle `30^@` has one of the refractive surfaces polished. A beam of light incident on the other surfaces will trace its path if the angle of incidence is

Options

A. `0^(@)`
B. `30^(@)`
C. `45^(@)`
D. `60^(@)`

Answer

C

Explanation

(c ) Light should fall normally on the silvered face i.e.,
`r_(2)=0`
`therefore r_(1)=A=30^(@)`
Now, Refractive index, `mu`=`sini_(1)/sinr_(1)`
or `sqrt2=sini_(1)/sin 30^(@)`
Angle of incidence, `i_(1)=45^(@)`