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Homework Help: Separation of two wavelengths in a diffraction grating.

  1. May 9, 2010 #1
    1. The problem statement, all variables and given/known data
    Light with two wavelengths (510.0 nm and 525.6 nm) is spread by a diffraction grating. On a screen 4 meters behind the grating we observe that the diffrence between the two second order maximum is 1 cm. What is the grating constant (d) ?


    2. Relevant equations
    I think i only need Snells Law for this problem, and some geometry.


    3. The attempt at a solution
    Im having som problem with the geometry of the solution. I need to find the distance to one of the maximums from the zero order maximum. Ive found the relations:
    sin(a)=([tex]\lambda1[/tex]/[tex]\lambda2[/tex])*sin(b)
     
  2. jcsd
  3. May 9, 2010 #2
    Snell's law? You might want to use the formula for maxima's of a diffraction grating:

    [tex]d \sin \theta_m = m\lambda[/tex]
     
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