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Homework Help: Polarization Reflection question

  1. Apr 26, 2006 #1
    A thin film of ethyl alcohol (n=1.36) is spread on a flat glass plate and illuminated with white light. When illuminated and viewed from directly above, it shows a coloured pattern in reflection. If the only visible light reflected by a certain region of the film is yellow (lambda=560nm), how thick is the film there? Justify (assume visible spectrum is 400-7800nm)


    I have no idea where/how to start and what it involves.

    I have a feeling it invovles Huygen's Principle and Polarization by Reflection.
  2. jcsd
  3. Apr 26, 2006 #2


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    Staff: Mentor

    What thicknesses of ethyl alcohol will result in the yellow light reflected off the top surface and the yellow light reflecting off the alcohol-glass surface being in phase as they head back up to the observer?
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