【Daily Question】Theoretical Foundation 2020.06.09
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Multiple-choice question: A beam of natural light passes vertically through two polarizers, with the polarization directions of the two polarizers at an angle of 45°. Given that the light intensity after passing through these two polarizers is I, the intensity of the linearly polarized light incident on the second polarizer is: ( ) A. I B. 2I C. 3I D. I/2 Answer: B Hint: Extra rewards will be given to those who can explain the solution process; the answer can be found in the response!
B. Natural light becomes polarized light after passing through a polarizer, and its intensity is reduced by half after passing through it. The intensity of polarized light is calculated using Malus’s law: if the intensity of the incident polarized light is I0, then the intensity of the light that passes through a polarizer whose polarization direction is at an angle α to that of the incident light (without taking into account the absorption of light by the polarizer) is I. When α = 0° or 180°, I = I0, meaning the intensity of the transmitted light is maximum; whereas when α = 90° or 270°, I = 0, meaning the intensity of the transmitted light is minimum. Let the intensity of the natural light in this problem be I0; after passing through the first polarizer, the intensity becomes I0/2, and after passing through the second polarizer, the transmitted intensity is… This question asks for the intensity of light incident on the second polarizer, so it should be I0/2 = 2I.
A beam of natural light passes vertically through two polarizers, whose polarization directions are at an angle of 45° to each other. Given that the light intensity after passing through these two polarizers is I, the intensity of the linearly polarized light incident on the second polarizer is: (