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Homework Help: Compton Effect

  1. Jan 31, 2007 #1
    Hallo

    I don't understand why I can't use

    Δλ = λ'- λ = h/(m·c) · ( 1 - cos φ )
    and ΔE = h · c / Δλ

    for getting the energy ΔE which is transferred to the electron

    In school we did it like this: 1/f'- 1/f = h/(m·c) · ( 1 - cos φ )
    <-> E' = hf' = hf/(1 + hf(1 - cos φ )/(mc^2))

    -> ΔE = E (energy of photon before scattering) - E' (energy of photon after)

    I really need help

    Christoph
     
  2. jcsd
  3. Jan 31, 2007 #2

    jtbell

    User Avatar

    Staff: Mentor

    [tex]\Delta E = E^\prime - E = \frac{hc}{\lambda^\prime} - \frac{hc}{\lambda} = hc \left( \frac{1}{\lambda^\prime} - \frac{1}{\lambda} \right)[/tex]

    This does not equal [itex]hc / \Delta \lambda[/itex] because

    [tex]\frac{1}{\lambda^\prime} - \frac{1}{\lambda} \ne \frac{1}{\lambda^\prime - \lambda}[/tex]
     
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