Light is incident at an angle `i` on a glass slab. If the reflected ray is completely polarised , then the angle of refraction is

Options

A. `180^@-i`
B. `90^(@)+i`
C. `i`
D. `90^(@)-i`

Answer

D

Explanation

When the reflected ray is completely polarised, the ray is incident at the polarising angle i.

In this case ,`angle CBD=90^(@)`
`:. i+r+90^(@)=180^(@)`
`:. i+r=90^(@) " " :. r=90^(@)-i`