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Homework Help: I Need Some Help .

  1. Nov 30, 2004 #1
    I Need Some Help:(.....

    In a water tank experiment,water waves are generated with their srests 2.5 cmapart and parallel.they pass through two openings 5.0 cm apart in a long wooden board.If the end of the tank is 2.0 m beyond the boards,where would you stand ,relative to the "straight - through " direction,so that you recieved little or no wave action?

    this question seems very easy but i just could not end up solvin it ,i used the equation Yk/D = k x lambda /d ,but i couldnt quiet understand how i would find where it would have no wave reaction

    I am waiting for your comments,

    thanks already.......
  2. jcsd
  3. Nov 30, 2004 #2
    you want have any wave where the two waves which are coherent meet out of phase and cancel each other out........
    so from the given data we can see that lambda=2.5cm, D=200cm, x=5cm So you can find the separation the first "dark" fringe has with the central one.
    2.5=5y/200 So y=100cm
    Although I have not completely understood the tern "Straight through" I think Iam correct
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