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Double Slits, Calculating Wavelength

  1. Nov 6, 2013 #1


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    1. The problem statement, all variables and given/known data

    The following data was obtained upon using a double-slit experiment. Use this data to determine the wavelength of light being used to create the interference pattern. Do this in three different ways.

    - The angle to the eight maximum is 1.12°
    - The distance from the slits to the screen is 302 cm
    - The distance from the first minimum to the fifth minimum is 2.95cm
    - The distance between the slits is 0.025cm

    2. Relevant equations

    3. The attempt at a solution

    My work is shown in this image: http://gyazo.com/b9625064b97100febb726a6f6a12236a

    I believe I have interpreted the information correctly. I also believe methods 1 and 3 are correct as they were the most obvious. I have placed a series of question marks on method 2, which I am having trouble understanding. I don't believe they have given me sufficient information to solve this problem as is.

    After I have 3 values for wavelength, I plan to average them out to get a final answer.

    Does anyone have any insight to this? I seem to be missing a very important variable and I'm not sure how to go about it.
  2. jcsd
  3. Nov 6, 2013 #2


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    Friendly bump, Is it safe to say this problem is not solvable?

    If I knew the distance from a nodal line to the right bisector I could solve this, but I can't see how to get it for some reason.

    All I seem to know is the distance between two consecutive nodal points, namely ##\Delta x = 0.7375cm##.

    Would that mean half of that distance, ##\frac{\Delta x}{2}##, is the distance between a node and an antinode?

    If so, could I not consider the distance between the central maximum (which is exactly where the right bisector would happen to be) and the closest node to it? That would give me a workable value of ##x_1 = \frac{\Delta x}{2}## and ##n = 1##.

    This doesn't feel right to me though, does anyone have any thoughts?
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