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Homework Help: Emission of photo by electron

  1. Jul 29, 2008 #1
    an electron travels at 1 x 106 m/s. when it hits a target, its speed decrease in half and a photo is released. find the phton's wavelength.

    so far i know E photon = (hc) / lamda

    what about the speed? does the photons' energy same as kinetic energy of the electron which is just 1/2 mv ^2? if so, do i use the halved speed or the initial?
  2. jcsd
  3. Jul 29, 2008 #2


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    Apply conservation of energy:

    E_electron_inital = E_electron_final + E_phton
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