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Homework Help: Dark fringes problem

  1. Nov 27, 2004 #1
    Hey, another question I'm working on.

    How many dark fringes will be produced on either side of the central maximum if light, (651nm) is incident on a single slit that is 5.47 x 10^-m wide?

    Ok, I figure I could use this forumula sin@= m x lambda/Width. Am I trying to locate the maximum m (the order of the dark fringe) that it'll go?

    I tried solving for m=1 and got a angle of 6.83 degrees. Now where to?
    Any tips/hints welcome.

  2. jcsd
  3. Nov 27, 2004 #2


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    What do you know about the range of values of sin@ ?
  4. Nov 27, 2004 #3
    I missed something, the W is suppose to be 5.47x10^-6 m. Well, I know it can't go past 90 degrees and the min is the central max, which is 0 degrees.
  5. Nov 27, 2004 #4
    So if I put sin90=m x lambda/W and solve for m, then I'll get 8.40? so 8 dark fringes?
  6. Nov 27, 2004 #5
    can someone verify please and thanks
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