1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Electron Undergoing Annihilation

  1. Apr 13, 2005 #1
    A 5MeV electron undergoes annihilation with a positron that is at rest, producing two photons. One of the photons travels in the direction of the incident electron. Calculate the energy of each photon.

    So the 5 MeV electron undergoes annihilation with a positron and from that 2 seperate photons are formed. The energy of both photons should equal back up to the 5 MeV correct? Also one of the photons travels back the same way the electron came but I am not clear on how to use that piece of info.
  2. jcsd
  3. Apr 13, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Don't forget to include the rest energy of the stationary particle. Is 5 MeV is the total energy or kinetic energy of the other one?

    You need to conserve both momentum (a vector) and energy (a scalar).
  4. Apr 13, 2005 #3
    Ah, right..momentum is conserved. So the particles will be a sum of the 5MeV and the rest energy of that positron.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Electron Undergoing Annihilation