Unpolarised light is incident on a plane glass surface. What should be the angle of incidence so that the reflected and refracted rays are perpendicular to each other?

Explanation

For `i + r` to be equal to `pi//2`, we should have tan `i_(B) = mu = 1.5.` This gives `i_(B) = 57^(@)`. This is the Brewster.s angle for air to glass interface.