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1-D wave interference

  1. Mar 18, 2009 #1
    1. The problem statement, all variables and given/known data
    Monochromatic light of wavelength [tex]\lambda[/tex] = 400 nm enters at A. It impinges on a ‘half-silvered mirror’ B, which directs some of the light to mirror C, while passing the rest to mirror D. Some of the reflected light from mirror C passes back through the half-silvered mirror, where it combines with reflected light from D, arriving at the detector. Mirror C is attached to a micrometer, so that it can be moved to change the path length B − C − B.
    If mirror C is moved through 10 microns (1 micron is 10−6 m), how many maxima will be
    observed at the detector? Assume that the intensity at D is intially a minimum.

    2. Relevant equations

    3. The attempt at a solution
    I'm actually not sure how to approach this to begin with, so any advice is appreciated. I've also attached a copy of the diagram. I'm thinking this might have something to do with the path length being x1 and x2

    Attached Files:

  2. jcsd
  3. Mar 19, 2009 #2


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    Hi XJellieBX! :smile:

    If mirror C is moved through 10−6 m, how much longer does that make the path?

    So how many wavelengths is that? And how many maxima will go past?
  4. Mar 19, 2009 #3
    So if I find how many wavelengths that is, which i did find, i can figure out the number of maxima. I'm just not too sure if that is all this question is asking for, but thank you nevertheless =)
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