(a) Show, giving via suitable diagram, how unpolarized light can be polarised by reflection.
(b) Two polaroids P1 and P2 are placed with their pass axes perpendicular to each other. Unpolarised light of intensity I0 is incident on P1. A third polaroid P3 is kept in between P1 and P2 such that its pass axis makes an angle of 60∘ with that of P1. Determine the intensity of light transmitted through P1,P2 and P3.