Question

If a light beam shows no intensity variation when transmitted through a polaroid which is rotated, does it mean that the light is unpolarized? Explain.

Answer 1

Yes, the incident light  is unpolarised.  

Explanation :  

If incident light is unpolarised, the intensity of transmitted light through a polaroid is always I₀/2, which is constant. But if incident light is polarised, the intensity variation I = I₀cos²θ, necessarily takes place.

Since it is given that there is no intensity variation, Hence the incident light  is unpolarised.