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Homework Help: Diffraction Grating

  1. Mar 12, 2008 #1
    light wavelengths of 520nm and 630nm passes through a diffraction grating that contains 6000lines/cm. a) sketch a diagram of the image produced from m=0 to m=2. label the order of each fringe.b) calculate the angles for the first and second-order maxima that would appear on the screen. c) What is the lowest value of m for which the 520-nm line no longer exists? I have no idea how to do this question:(..
  2. jcsd
  3. Mar 12, 2008 #2
  4. Mar 12, 2008 #3
    i still don;t get it :(
  5. Mar 12, 2008 #4
    you have all the data u want...
    For (1) , there is a central maximum at theta =0 where the two rays coincide...
    and the greater the wavelength , the greater the theta the ray is for the same order...
    (sin function is increasing between 0 to pi/2)
    (2) sintheta = nlamda/d
    you have the slit separation , lamda and n , so it is possible to calculate

    c) No longer exist when sin theta >1
  6. Mar 12, 2008 #5
    the picture will be similar to the one shown in the website?..do i need to use protractor for that?
  7. Mar 12, 2008 #6
    sketch.... I don't think you need to do that:devil:
  8. Mar 12, 2008 #7
    label the order of each fringe? what does this mean?
  9. Mar 13, 2008 #8
    for part b) sintheta=mlmbda/d....do i use both wavelengths? or a difference of the wavelengths?....confused:S
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