A horizontal ray of light passes through a prism of index `1.50` and apex angle `4^(@)` and then strikes a vertical mirror , as shown in the figure. Through what angle must the mirror be rotated if after reflection the ray is to be horizontal?

Options

A. `4^(@)`
B. `90.5^(@)`
C. `1^(@)`
D. `1.5^(@)`

Answer

C

Explanation

`delta = (mu-1) A implies 2^(@)`
To make it horizontal

mirror should rotate = `(2^(@))/(2) implies 1^(@)`