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Homework Help: Double Slit Interference

  1. Aug 15, 2008 #1
    1. The problem statement, all variables and given/known data
    We have the wavelength of 550nm and the distance (d) of 0.120mm. I need to calculate the the angle q.
    The diffirent parts of this questions corresponds to the diffirent order of n. a) Being n=1 b) n=5 c) n=10

    Given variables;
    Wavelength = 550nm = 550*10^-9m
    d=0.120mm = 0.00012m
    n1= 1
    n2= 5
    n2 = 10

    2. Relevant equations
    The relevant equation for this is;

    d*sin0 = n*Wavelength
    0 = sin((n*Wavelength)/d))

    3. The attempt at a solution

    I've attempted the solution to this and my real problem is that I have got no idea how to get the answer to Degrees. I'd really like to see someone do this so I can see what you do and how I should think.
  2. jcsd
  3. Aug 15, 2008 #2


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    What answers are you getting? You have the correct formula if you are using the inverse sine function.
  4. Aug 15, 2008 #3
    The answer im getting is like 0.004[insert alot of numbers here]
    The answer it's supposed to be is 29degrees.

    The question is; How do I get the answer that I got 0.004(something) to degrees?
    You try it and we can see how you do it.

    The answer is supposed to be 29degrees.
  5. Aug 15, 2008 #4


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    Hmm, going through myself I can get nowhere near the answer. The only thing I can think of is the slit distance should be about 1.1 micrometres to get 29 degrees for the first order.
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