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Homework Help: Intensity of light through two polarizers and Malus's Law

  1. Apr 14, 2010 #1
    1. A beam of unpolarized light with intensity I_0 falls first upon a polarizer with transmission axis theta1 then upon a second polarizer with transmission axis theta2, where theta2 - theta 1 = 90 degrees (in other words the two axes are perpendicular to one another). What is the intensity I_2 of the light beam emerging from the second polarizer?

    2. Malus's Law

    3. Would the answer be 0.25I0, i.e. the intensity is cut in half each time, so the final intensity is 1/4 the initial intensity?
  2. jcsd
  3. Apr 14, 2010 #2
    Actually, is it just 0?
  4. Apr 14, 2010 #3


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    Homework Helper

    Can light go through the crossed polarizers?

    Half the intensity is transmitted if the incident beam is unpolarized, but after the first polarizer, it is polarized.

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