A ray of light passes from vaccum into a medium of refractive index n. If the angle of incidence is twice the angle of refraction, then the angle of incidence is

Options

A. `cos^(-1)(mu//2)`
B. `2cos^(-1)(mu//2)`
C. `2sin^(-1)(mu)`
D. `2sin^(-1)(mu)`

Answer

2

Explanation

`mu=(sini)/(sinr) implies mu= (sin2r)/(sinr) (sin2theta=2sinthetacostheta)implies r=cos^(-1)(mu/2)`. So, `i=2r=2cos^(-1)(mu/2)`