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Homework Help: What sort of photon is this?

  1. Nov 4, 2004 #1
    A photon of frequency [tex] \nu [/tex] collides elastically with an electron at rest. The phton loses half its nergy in the collision an its final path makes a 60 degree angle with the original path. What is [tex] \nu [/tex] ? what sort of photon is this?

    Well this is obviously the compton effect

    [tex] \lambda_{1} - \lambda = \frac{h}{mc} (1 - Cos \phi ) = 1.21 * 10^12[/tex]

    Then Also the photon lost half it's energy so

    [tex] \frac{h \nu}{2} = \frac{h \nu '}{2} [/tex]
    and figure that [tex] 2 \lambda = \lambda ' [/tex]

    and then lambda = 1.21 * 10^12?

    then [tex] \nu = 4.04 * 10^21 Hz [/tex]

    which is a gamma ray?

    am i right in this? i have my doubts about the lambdas

    Also i have another thread i need some help would greatly appreciate with both! Thank you!!

    Last edited: Nov 4, 2004
  2. jcsd
  3. Nov 5, 2004 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Your thinking is correct...
    ...but watch those exponents. I assume you meant to write 1.21E-12.
    redo that calculation.

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