A polarizer (with its preferred direction rotated 30° to the vertical) is placed in a beam of unpolarized light of intensity 1. After passing through the polarizer, the beam's intensity is
A) 0.7501.
B) 0.5001.
C) 0.2501.
D) 0.8661.
E) 0.5000.

Question

Quizplus · Accepted Answer

The intensity of light after passing through a polarizer is given by Malus's law, which states that the intensity of polarized light after passing through a polarizer is I = I0 * cos^2(θ), where I0 is the initial intensity and θ is the angle between the light's initial polarization direction and the axis of the polarizer. For unpolarized light, I0 is reduced by half upon passing through the polarizer, regardless of the angle, because unpolarized light has equal intensity in all polarization directions. Therefore, the intensity after passing through the polarizer is 0.5 * I0 = 0.5 * 1 = 0.5000.

A Polarizer (With Its Preferred Direction Rotated 30° to the Vertical)