Two Polaroids P 1 and P 2 are placed with their axis perpendicular to each other. Unpolarised light with intensity I 0   is incident on P 1 . A third polaroid P 3 is kept in between P 1 and P 2 such that its axis makes an angle 45 o with that of P 1 . The intensity of transmitted light through P 2 is

Step-by-step solution

By Malus law, the intensity of transmitted light via P 1 is I 1 = I 0 2 The intensity of light transmitted through P 3 as obtained from the above figure is I 2 = I 0 2 cos 2 ⁡   45 o = I 0 2 × 1 2 = I 0 4 Intensity of light transmitted via P 2 is I 3 = I 0 4 cos 2 ⁡ 45 o I 3 = I 0 8