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Homework Help: Compton scattering MCQ

  1. Nov 4, 2007 #1
    1. The problem statement, all variables and given/known data

    A photon of wavelength [tex]\lambda[/tex] enters an electron gas.What is the minimum number of collisions that could result in the photon being completely absorbed in the gas?

    (a) [tex]\approx[/tex][tex]\lambda[/tex][tex]\frac{mc}{2h}[/tex]

    (b) [tex]\approx[/tex][tex]\lambda[/tex][tex]\frac{mc}{h}[/tex]

    (c) [tex]\approx[/tex][tex]\lambda[/tex][tex]\frac{2mc}{h}[/tex]

    2. Relevant equations
    3. The attempt at a solution

    I have done in following way:

    It can be shown that for compton scattering,

    [tex]\frac{ E }{ \Delta E }[/tex]=[tex]\frac{mc^2}{ h\nu\[1-cos\phi]} [/tex]

    where [tex]\large E[/tex] is the initial energy of the photon and [tex]\Delta E[/tex] is the energy lost per scattering phenomenon.

    Now,demanding for the minimum number of collision,I had (a) the correct answer corresponding to [tex]\phi[/tex]=[tex]\ 180 [/tex][tex]\circ[/tex]. What does the scattering angle imply?

    Please check my work.
    Last edited: Nov 4, 2007
  2. jcsd
  3. Nov 4, 2007 #2
    I posted h(nu) times (1- cos phi)

    and in the last but one line, phi=180 degree
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