Plane polarized light is sent through two consecutive polarizers,the first having its plane of polarization in the same direction as the incident light and the second having its plane at 90 $\degree$ to the original plane of polarization.A third polarizer,with plane of polarization at 30 $\degree$to the original plane of polarization,is placed between the two other polarizers.What fraction of the original intensity now gets through?
A)0
B)0.56
C)0.25
D)0.19

Question

Quizplus · Accepted Answer

When plane polarized light passes through the first polarizer, the intensity remains the same. Now, the second polarizer is oriented perpendicular to the original plane of polarization, so the intensity drops to zero because all the light is now polarized perpendicular to the transmission axis of the second polarizer.

When the third polarizer is introduced between the two other polarizers, it only allows  cos^2(30°) = 0.75  of the light through because the angle between its transmission axis and the plane of polarization is 30°.

Therefore, the fraction of the original intensity that gets through is:
I_final/I_initial = 0.75 x 0 = 0 
So the answer is D.

Plane Polarized Light Is Sent Through Two Consecutive Polarizers,the First °\degree°

Plane Polarized Light Is Sent Through Two Consecutive Polarizers,the First $\degree$