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DeBroglie wavelength based on kinetic energy

  1. Feb 11, 2017 #1
    1. The problem statement, all variables and given/known data
    I am working on a problem similar to this one:
    In this solution, I do not understand what mc is, can someone explain? Also, would I follow the same type of steps if I have the kinetic energy of a photon and I need it's wavelength?

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Feb 11, 2017 #2


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    Staff: Mentor

    Looks like a typo. It should also be ##m_e##, the rest mass of the electron.

    Photons have no rest mass. Setting it to zero in the equation in your problem yields p = K/c, where K is the energy of the photon. That's a valid result linking energy and momentum for a photon. To get at the wavelength appeal to the Planck relationship, ##E = h \nu##.
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