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Homework Help: Diffraction Grating lines

  1. Mar 7, 2010 #1
    1. The problem statement, all variables and given/known data

    The figure shows the interference pattern on a screen 1.0 m behind a diffraction grating. The wavelength of the light is 600 nm. How many lines per millimeter does the grating have?


    2. Relevant equations

    lines/mm = 1/ distance between slits


    3. The attempt at a solution
    Quite frankly I don't have a clue how to solve this. I know that the number of lines per millimeter is equal to the inverse of the distance between slits, but what happens if there are more than 2 slits of different distances from each other? I took a shot in the dark and tried to add up the reciprocals of all the distances, but that proved to be incorrect because it gave me a very small number around 0.006. Does anyone have any helpful suggestions?
     

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  2. jcsd
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