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Reflection problem (optics)

  1. Dec 6, 2006 #1
    1. The problem statement, all variables and given/known data
    I have a transparent plate (call the thickness t and refractive index n), it has a scratch at a point A. A microscope objective (M, positive) images the point A in A' at a distance D from the objective. If we move M a certain distance d down (without changing focus, meaning D is unchanged), there will be another sharp image of the scratch.

    How come?

    2. Relevant equations

    Not needed?

    3. The attempt at a solution

    I was thinking that it might be some reflection on the objective that reflects the light back to the plate and back to the objective at the same point as before it was moved, and then refracted towards A'. I'm not sure if I understand the problem correctly... I think it is suggesting a second image somewhere else?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Dec 6, 2006 #2
    Ok, I tried illustrating the problem. Please check the attachment (hope it helps).
     

    Attached Files:

    • p2.jpg
      p2.jpg
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