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Homework Help: Recoiling electron

  1. Sep 13, 2005 #1
    i am having a little bit of trouble with this problem

    An x-ray photon of initial energy 1*10^5 eV traveling in the +x direction is incident on a free electron at rest. The photon is scattered at right angles into the +y direction. Find the components of the recoiling electron.


    since we are given the initial energy i used the relation
    [tex]
    E=\frac{hc}{\lambda}
    [/tex]
    to find lambda, i then used comptons equation
    [tex]
    \lambda'-\lambda=\frac{h}{m_ec}(1-cos\theta) ; \theta=90
    [/tex]

    then using
    [tex] P=E/C = 1*10^5 \frac{eV}{c} \hat{x} [/tex]
    [tex]
    \lambda'=\frac{h}{m_ec}+\lambda
    [/tex]

    where [tex]\lambda'[/tex] is the wavelength after the collision so

    [tex]
    E'=\frac{hc}{\lambda'}[/tex]

    [tex]
    P'=\frac{E'}{c}=8.4*10^4 \hat{y}
    [/tex]

    since P_initial=P_final
    P_initial= [tex]1*10^5\hat{x} +0\hat{y}[/tex]

    p_final=[tex]1*10^5\hat{x} + 8.4*10^4-8.4*10^4\hat{y} [/tex]

    therefor [tex]P_e= 1*10^5\hat{x} - 8.4*10^4\hat{y} [/tex]

    just wondering if this seems right, if not some help would be great thanks.
     
  2. jcsd
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