Question

When a unpolarised light is incident on a plane glass surface, what should be the angle of incidence, so that the reflected and refracted waves are perpendicular to each other?

Answer 1

The unpolarized light is incident on a plane glass surface at an angle i, such that tan i = μ, where μ is refractive index of glass.

In that case, the reflected and refracted waves are perpendicular to each other and the reflected light is completely plane polarized.