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Newton's Rings using refractive index of water

  1. Nov 30, 2015 #1

    I am currently looking at Newtons Rings, i have changed my refractive index to water (distilled), i have found the rings and they seem to be as aspected except they are extremly faint barely readable infact would anyone know a cause or soulation to this?
  2. jcsd
  3. Nov 30, 2015 #2
    It's hard to say without more detail of your experiment.
    What index did you changed to water? Or of what?
    Did you put water between the curved surface and the plane surface?
  4. Nov 30, 2015 #3
    i changed the index from air to water to see the affects, yes i did byt it between the curved surface and the plane surface.

    The lense i am using is a planeo-convex lens and i have my glass slide at 45 degrees my lamp is also a sodium!
    this is a picture of my set up

    Attached Files:

  5. Nov 30, 2015 #4
    Well, by replacing air with water you decrease the intensity of the reflected light at both interfaces.
    The reflection coefficient depends on the difference between the indices. If you reduce the difference more light will just get through, without being reflected.

    What would you expect if you replace the water with glass of the same index as the lens and slide (without any air at the interface)?
  6. Nov 30, 2015 #5


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    As the light travels slower in the water, it is equivalent to having a bigger gap, and so the rings will be more closely spaced and harder to see.
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