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Homework Help: Finding a point midway between two electric charges

  1. Apr 13, 2008 #1
    1. The problem statement, all variables and given/known data
    Two point charges of magnitude 2nC and -4nC are separated by 35 cm. The Coulomb constant is 8.98755e9 Newtons (Meters squared/ Coulombs squared). What is the potential difference between a point infinitely far away and a point midway between the charges?

    R= .175

    2. Relevant equations

    E = Kc (q/r^2)

    Magnitude of electric field = Coulomb's Constant (value of the charge/ Distance squared)

    Delta V = Kc (q/r)

    Potential difference = Coulomb's Constant (value of the point charge)/ (distance to the point charge)

    3. The attempt at a solution
    I tried running the two separate charges into the first formula (E1= 587, E2= -1174), then added them together, then ran the second formula with the difference of the first two (1761) and ended up with (9.04e13).

    Call me crazy, but isn't that quite a bit of voltage for such a tiny amount of charges? Where am I going wrong?
  2. jcsd
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