Question

Two polaroids, P₁ and P₂, are set-up' so that their'pass-axis' are 'crossed' with respect to each other. A third polaroid, P₃, is now introduced between these two so that its 'pass-axis' makes an angle  θ with 'pass-axis' of P₁. A beam of unpolarised light, of intensity I, is incident on P₁. If the intensity of light, that gets transmitted through this combination of three polaroids, is 'I'. find the ratio (I'/I) when  θ equals : 

(i) 30°, (ii) 45°.

Answer 1

Intensity of unpolarised light is given as I,

lt becomes I/2 on passing polaroid P₁