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Selected formulas from FLF

  1. Dec 8, 2005 #1
    In the Vol. I, 27-7 of Feynman's Lectures on Physics, he derives
    a formula for the resolving power of an optical system from the general rule t2 - t1 > 1/nu (nu is frequency) as D > lambda/n*sin(teta).
    It appears, however, from the corresponding Fig. in the book that the latter inequality should have a form D > lambda/2*n*sin(teta), i.e.
    the right side is two times smaller.
    The approximate equality I derived from the Fig. is
    (P'R - P'S)*2*(PS) = 4*(PS)*D*sin(teta).
    Since P'R - P'S = c*(t2 - t1) and c/n*(nu) = lambda we get formula
    with 2 in the denominator.
    Is that the mistype in the book or am I missing something?
  2. jcsd
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