Question

two polaroids A and B are kept in crossed position. How should a third polaroid c be placed between them so that The intensity of polarized light transmitted by polaroid B reduces to 1/8 of the intensity of unpolarised light Incident on A.

Answer 1

The third polaroid should be placed in such a way that it should bisect the angle b/w the two polaroids... it should be at an angle of 45* from polaroid A ... So intensity of light coming out of A= I/2 ....Then using Malus Law, After C= I/2* Cos2(theta) = I/2*Cos2(45*) = I/4...

After B= I/4 Cos2(45) = I/8 ...