A horizontal ray is incident on one of the refracting faces of a prism of angle 8°. The ray strikes a vertical plane mirror after refraction as shown in figure. What should be the angle (in degrees) by which the mirror should be rotated in order to make the reflected ray antiparallel to incident ray ?
(Take R. I. of material of prism = 5/4 )

Answer

`01.00`

Explanation

For thin prism,
`delta = (mu-1)A = (5/4 -1) xx 8 = 8/4 = 2^(@)`

By geometry of the figure, angle through which the mirror should be rotated in order to make the ray horizontal is `theta = 1^(@)`