What is the angle of incidence for an equilateral prism of refractive index `sqrt(3)` so that the ray si parallel to the base inside the prism?

Options

A. `30^(@)`
B. `20^(@)`
C. `60^(@)`
D. `45^(@)`

Answer

C

Explanation

`""_(a)mu_(g)=sqrt3`
the refracted ray is going parallel to the base.
So, from the geometry, corresponding angle will be equal `rArr angleM=angleB=60^(@)`
At point M, `r+60^(@)=90^(@)`
`r=30^(@)`
`(sini)/(sinr)=""_(a)mu_(g)=sqrt3`
`(sini)/(sin30)=sqrt3= rArr sin i=(sqrt3)/(2)`
`rArr" "i=60^(@)`