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Homework Help: Interference and Inferometer

  1. Feb 11, 2013 #1
    - why is it that fewer rings are observed when the plates are moved closer together (given wavelength , monochromatic source). What equation shows this relation?

    - Consider a non-monochromatic source, such as a Sodium Lamp, as the distance varies, both patterns change but at differnt rates - one will change at a faster rate than the other - which one changes quicker - the D line with the greater or smaller wavelength? And why is this, again is there an equation to show this relation?

    - As the distance between the plates is changed, the number of rings observed changes also - are there any other observable affects varying with this distance?

    Thanks alot anyone for any assistance !
  2. jcsd
  3. Feb 12, 2013 #2

    Simon Bridge

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    also see: your other thread about this interferometer for the context.
    Take a look at the geometry panel - when the path difference (length CD) is an integer number of wavelengths you get constructive interference and thus a maxima. CD depends on the angle and how far apart the plates are by simple geometry.

    To understand this - sketch the diagram with different plate separations.

    Again, it is the path difference equation ... the path difference needs to be a whole number of wavelengths.
    Work it out.

    What sort of effect did you have in mind?
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