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Electrical potential problem

  1. Mar 27, 2014 #1
    The problem is to find the potential at a point that is 3 meters away from two charges. (one 3 meters above, and the other 3 meters below)


    I put that Ep=Epq1+Epq2



    This gives me:


    Which immediately set some bells off for me. Isnt that quite a bit of energy for a charge three meters away? By the same formula, Epq2 equals 17976J, for a total potential of 26964J. Maybe I am wrong, but it seems like a very high potential. I will admit that I havent wrapped my head around how large of charge a Coulomb is, so maybe 3μC and 6μC are very large amounts of charge, but something seems wrong to me...

    Can someone take a look, and see if I did something wrong? Thank you.
  2. jcsd
  3. Mar 27, 2014 #2


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    Hello, Latsabb.

    Note that you are calculating potential, not potential energy. The unit of potential is not J.

    A μC is a large amount of charge for a particle. So, a large value of potential in this problem is to be expected.
  4. Mar 27, 2014 #3
    Ok, thank you. Being that I am not calculating potential energy, that would make this... Volts? So I should be replacing my Ep's with V?
  5. Mar 27, 2014 #4


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    Yes. So, you are getting some "high" voltages because your charges are on the order of a few μC and your distances are on the order of a few meters.
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