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Homework Help: # of diffraction orders seen?

  1. Mar 30, 2008 #1
    # of diffraction orders seen???

    1. The problem statement, all variables and given/known data
    A 513 line/mm diffraction grating is illuminated by light of wavelength 567 nm. How many diffraction orders are seen?

    2. Relevant equations

    3. The attempt at a solution
    d*sin theta = mt
    t = wavelength

    m = d*sin theta/t
    I don't have the angle so I just omitted it assuming it would be very small and I did...
    m = d/t = 3.4 so 3 diffraction orders

    Is this correct?
  2. jcsd
  3. Mar 30, 2008 #2
    Does anyone know how to do this?
  4. Mar 30, 2008 #3
    The value of sin has to be at a maximum (ie. 1), so the angle is 90 degrees. What you did looks right. If the angle was very small, then m would also be very small.
  5. Mar 30, 2008 #4
    Thank you so much! I have a test on Thursday and I am having a hard time understanding light!!
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