question_answer

A beam of unpolarised light of intensity\[{{I}_{0}}\]is passed through a polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of\[45{}^\circ \] relative to that of A.

The intensity of the emergent light is:                                                [JEE MAIN 2013]

A) \[{{I}_{0}}\]

B) \[{{I}_{0}}/2\]

C) \[{{I}_{0}}/4\]

D) \[{{I}_{0}}/8\]

Correct Answer: C

Solution :

[c] Intensity of light is halved upon passage through first polaroid.

Using Malus’ Law:

(The angle between the polarization axes of the polaroids)