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Homework Help: Potential energy problem. help >.<

  1. Sep 16, 2008 #1
    An electron and a proton are initially very far apart (effectively an infinite distance apart). They are then brought together to form a hydrogen atom, in which the electron orbits the proton at an average distance of 5.05e-11 m. What is EPEfinal - EPEinitial, which is the change in the electric potential energy?


    2. Relevant equations

    V=kq/r
    PEfinal=qVfinal

    3. The attempt at a solution

    since initially, r was very big and V very small, you can consider the initial potential energy to be zero... right?

    after that i calculated for V. V= (9.0e9)(-1.6e-19)/5.05e-11 = -28.5148.
    what do i do from here? I multiplied by the charge of the electron again and got 4.5623e-18 but that's wrong?

    any light that can be shed on this will be greaaaaaaaaatly appreciated. thanks! :smile:
     
  2. jcsd
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