A prism ABC of angle `30^(@)` has its face AC silvered. A ray of light incident at an angle of `45^(@)` at the face AB retraces its path after refraction at face AB and reflection at face AC . The refractive index of the material of the prism is

Answer

A, B, C, D

Explanation

Given, `A=30^@, i_1=45^@ and r_2=0`
Since, `r_1+r_2=A`
`:. r_(1)=A=30^@`
Now, refractive index of the prism,
`mu=sini_1/(sinr_(1))=(sin45^@)/s(in30^@)=(1/sqrt2)/(1/2)=sqrt2`