A ray of light passes from vacuum into a medium of refractive index `mu`. 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)/(2))`
D. `2sin^(-1)(mu)`

Answer

B

Explanation

`mu=(sini)/(sinr)impliesmu=(sini)/(sin.(i)/(2))`
`impliesmu=(2sin.(i)/(2)cos .(i)/(2))/(sin.(i)/(2))`
or `cos .(i)/(2)=(mu)/(2)` or `(i)/(2)=cos^(-1)((mu)/(2))`
or `i=2cos^(-1)((mu)/(2))`