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

Question

Quizplus · Accepted Answer

Using three polarizing filters, each rotating the beam by 30°, results in the greatest intensity. According to Malus's Law, the intensity after passing through each filter is I = I₀ * cos²(θ), where θ is the angle between the light's initial polarization direction and the filter's axis. By using multiple filters with smaller angles, the intensity loss is minimized compared to using fewer filters with larger angles.

Polarized Light Is to Have Its Polarization Plane Rotated by 90°