Question

If the phase difference between two rays is π/2 and the angle of incidence is equal to π/4, the emergent light is __________

(a) Linearly Polarized

(b) Elliptically Polarized

(c) Circularly Polarized

(d) Non-Polarized

I had been asked this question in a national level competition.

My question is taken from Polarisation of Light in portion Polarisation of Engineering Physics II

Answer 1

Right choice is (c) Circularly Polarized

The explanation is: In this case, the equation of the emergent light becomes the equation of a circle, which is x^2 + y^2 = a^2. Thus, the emergent light is elliptically polarized and the plane of the ellipse is normal to the direction of propagation.