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Two wavelengths, max/min at same angle

  1. Mar 23, 2009 #1
    1. The problem statement, all variables and given/known data
    Light goes through two slits 40 mm apart. Does an angle exist at which light of wavelength 440nm has a maximum and light of wavelength 660nm has a minimum?


    2. Relevant equations
    dsin[tex]\theta[/tex]=m[tex]\lambda[/tex]1 = maximum
    dsin[tex]\theta[/tex]=(m+ 1/2)[tex]\lambda[/tex]2 = minimum


    3. The attempt at a solution
    I solved for sin[tex]\theta[/tex] in each case, so I got:

    m[tex]\lambda[/tex]1 = (m+ 1/2)[tex]\lambda[/tex]2

    [tex]\lambda[/tex]1 = 660nm
    [tex]\lambda[/tex]=440 nm

    Now I'm stuck. Both Ms do not have to be the same, right? So do I have to solve for one of the Ms and stick it into an equation I listed in part 2 above? If so, that's a crazy calculation. Thanks!
     
  2. jcsd
  3. Mar 23, 2009 #2

    Redbelly98

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    Correct, the m's can be different. But they must both be integers.

    Are the slits really 40 mm apart? That's pretty far for an optical double slit setup.
     
  4. Mar 23, 2009 #3
    They're actually 40 nm apart, sorry.
     
  5. Mar 23, 2009 #4

    Redbelly98

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    Are you sure it's not 40 μm?
     
  6. Mar 23, 2009 #5
    ah yes you're right
     
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