1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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)

    q1=3μC
    q2=6μC

    I put that Ep=Epq1+Epq2

    Epq1=K*q1/r1
    Epq2=K*q2/r2

    K=1/(4πε0)=8.988x109

    This gives me:

    Epq1=8.988x109*(3x10-6/3)=8988J

    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

    TSny

    User Avatar
    Homework Helper
    Gold Member

    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

    TSny

    User Avatar
    Homework Helper
    Gold Member

    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.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Electrical potential problem
Loading...