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? (Given n=1.5)

Explanation

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