Polarized light is to have its polarization plane rotated by 90 $\degree$.In which of the following cases does the final beam have the greatest intensity?
A)3 polarizing filters,each rotate beam by 30 $\degree$.
B)2 polarizing filters,both rotate beam by 45 $\degree$.
C)1 polarizing filter,rotating beam by 90 $\degree$.
D)None of the above,polarized light can't be rotated.

Question

Quizplus · Accepted Answer

When polarized light is passed through a polarizing filter at an angle, the intensity of the transmitted light decreases. Therefore, passing the light through multiple filters will result in further reduction in intensity.

In choice A, there are three filters each rotating the beam by 30°, resulting in a net rotation of 90° which matches the desired rotation. However, each filter only reduces the intensity by a certain factor, and using three filters results in the least overall reduction in intensity.

In choice B, there are only two filters rotating the beam by 45° each. This results in a net rotation of 90°, which matches the desired rotation. However, using two filters reduces the intensity more than using three filters as in choice A.

In choice C, there is only one filter rotating the beam by 90°, which matches the desired rotation. However, using only one filter results in the most significant reduction in intensity.

Therefore, choice A results in the greatest intensity of the final beam.

Polarized Light Is to Have Its Polarization Plane Rotated by 90