Question

A HWP is introduced between two crossed Polaroids P₁ and P₂ . The optic axis makes an angle of 15° with the pass axis of P₁ as shown in Fig. (a) and (b). If an unpolarized beam of intensity I₀ is normally incident on  P₁ and if  I₁ ,I₂ , and I₃ are the intensities after P₁ , after HWP, and after P₂ , respectively, I₃/I₀ is

(a)  1/2

(b)  1/4

(c)  3/4

(d)  1/8

Answer 1

Correct option   (d)  1/8

Explanation:

Unpolarized light of Intensity I₀ incident on Polaroid P₁ , the intensity I₁ will be I₀/2 . HWP introduce a phase difference of π , output of HWP will be linearly polarized with no change in the intensity at the output of HWP. The electric field vector of linearly polarized light will make angle 30∘ with the pass axis of the second polarizer.

According to Malu’s law intensity at output will be