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Homework Help: How do I find the spacing(d) of a grating in a diffraction grating experiment.

  1. Feb 28, 2012 #1
    1. The problem statement, all variables and given/known data

    http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_s02_qp_2.pdf

    question no. 7b

    2. Relevant equations


    3. The attempt at a solution

    I subtracted the two angles and got 26 degrees. So then I plugged it all into the equation:
    dsin26=2 X 630x10^-9.
    My answer is half the actual answer because the angle the answer sheet has is 13 degree. Why do they take it as 13 degree??
  2. jcsd
  3. Feb 29, 2012 #2


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    Homework Helper

    Look at the figure. The two angles correspond to the second-order maxima at both sides of the central maximum.
    You need to know what angle is called ∅.

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