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Homework Help: Thin film interference

  1. Apr 14, 2008 #1
    1. The problem statement, all variables and given/known data

    A pair of slits separated by d = 1.30 mm is illuminated with light of l = 610 nm wavelength and falls on a screen L = 2.00 m away. A piece of glass with index of refraction n = 2.2 is placed at one slit. If the maxima shift is Dx/2, and falls on a minimum, what was the minimum glass thickness (in meters)?

    2. Relevant equations/ Attempt at solution

    What is the significance of the Dx/2 shift maxima? Do I use the equation t =(m + 1/2)(wavelength) / 2n?

    I know that wavelength is 610 x 10^-9 m; n=2.2, but I'm not sure whether I'm trying to use the wrong equation because of the extra information.

    I'm also not sure whether I'm supposed to calculate a new wavelength of the light in the glass with n=2.2. If so, is it true that the wavelength(glass) = wavelength(air) / n(glass), therefore meaning that the new wavelength is (610nm)/(2.2) = 277.273 nm ?
  2. jcsd
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