Question

What angle should the beam made with the vertical, so that after passing through the analyzer, it’s intensity should become 0.86 times the initial intensity?

(a) 30°

(b) 45°

(c) 60°

(d) 75°

I have been asked this question in an online interview.

My question is taken from Production of Plane Polarised Light in division Polarisation of Engineering Physics II

Answer 1

The correct choice is (c) 60°

To elaborate: Here, I = 0.86 Io

Using Malus law, I = Iocos^2θ

0.86 Io = Io X cos^2θ

cos^2θ = 0.86

θ = 60°.