Unpolarized light of intensity 200 W/m² is incident on a polarizer A. Light leaving this polarizer is then incident on a polarizer B with its polarization axis oriented at 30 $\circ$ with respect to that of A. What is the intensity of the light leaving polarizer B?

Question

Quizplus · Accepted Answer

When unpolarized light passes through a polarizer, its intensity is reduced by half. Therefore, after passing through polarizer A, the intensity becomes 100 W/m^2. The intensity of light after passing through a second polarizer oriented at an angle θ with respect to the first is given by Malus's law: I = I_0 * cos^2(θ), where I_0 is the initial intensity and θ is the angle between the polarizers. Here, θ = 30 degrees, so the intensity after polarizer B is I = 100 W/m^2 * cos^2(30°) = 100 W/m^2 * (sqrt(3)/2)^2 = 75 W/m^2.

Unpolarized Light of Intensity 200 W/m2 Is Incident on a Polarizer

Unpolarized Light of Intensity 200 W/m² Is Incident on a Polarizer