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Self energy of electrons

  1. Feb 7, 2005 #1
    The following two questions regard the self energy of electrons.. Does anybody know how to start these? I used this site as reference but I wasn't sure if they help with these following questions: http://quantummechanics.ucsd.edu/ph130a/130_notes/node44.html

    Calculation 1: Pretend the electron is made up of two halves, each with charge e/2. How much energy is required to bring the two halves together, i.e., so that they occupy the same point in space?

    Calculation 2: That calculation was a bit over-simplified. Let’s do a better job. Pretend that the charge of an electron is spread uniformly over the surface of a spherical shell with radius r0. Next calculate the electric field everywhere in space, i.e., at an arbitrary distance r from the center of the shell. Obviously the answer will depend on r and r0. Next, calculate the total energy stored in the field, by integrating the energy density u over all space. Finally, let the “electron” become a point particle, by letting r0 go to zero.
  2. jcsd
  3. Feb 7, 2005 #2
    the questions you have to answer are classical electrodynamics, and you are looking at quantum effects and are in the wrong forum.

    to answer your question, remember the function for potential, and then remember that the potential specifies bringing a unit positive charge from infinity to some point in that field.
  4. Feb 7, 2005 #3


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    By the looks of it,the problem needs no quantum mechanical treatment at all.

    If it's classical,how would you do it,then??

    Why didn't u post it in the HM section??

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