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Electric Potential Energy question

  1. Sep 20, 2008 #1
    This isnt really a homework problem. I just want to understand electric potention
    [tex]\Delta[/tex]V=Uf-Ui=-W

    Uf= final
    Ui=initial

    Can someone explain to me how electric potential acts between two positive electrons, or two negative electrons or a + and a negative electron. In which cases would work be positive and why ?

    Thank you
     
    Last edited: Sep 20, 2008
  2. jcsd
  3. Sep 20, 2008 #2

    tiny-tim

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    Hi th3plan! :smile:

    We (arbitrarily) define the potential to be 0 at infinite distance.

    To bring a + charge near another + from infinity, you have to overcome the repulsion, so you have to do work on it.

    To bring a - charge near a + to infinity, you have to overcome the attraction, so you have to do work on it. :smile:
     
  4. Sep 20, 2008 #3
    so if work has to be done on it its considered -w , for a + to a + to be brought together, but for a + and a - u have to do work to bring together ? Why ? They naturally attract :S ?
     
  5. Sep 20, 2008 #4

    tiny-tim

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    Hi th3plan! :smile:

    No, you have to do work to separate them, to bring them to infinity. :smile:
     
  6. Sep 20, 2008 #5

    tiny-tim

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    Hi th3plan! Thanks for the PM. :smile:
    (Assuming the potential at infinity is 0?)

    The electric field points outward for a same charge, and inward for an opposite charge. :smile:
     
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