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Homework Help: Electric Field and Electric Potential

  1. Jan 15, 2012 #1
    1. The problem statement, all variables and given/known data
    Find the strength of the electric field midway between two point charges, q1=5.78nC and q2=-5.78nC separated by 68cm.

    2. Relevant equations


    3. The attempt at a solution
    I just tried the problem as a two step equation but it's giving me a huge answer. What am I doing wrong? Thanks.
  2. jcsd
  3. Jan 15, 2012 #2


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    Now how could anyone tell you what you are doing wrong if you don't show your work?
  4. Jan 15, 2012 #3
    I plugged the numbers on the first equation, which gave me the force.

    Then plugged force into the second equation and divided by q, but it's giving me a huge huge number.
  5. Jan 15, 2012 #4
    Did you convert the 68cm to m?
  6. Jan 15, 2012 #5


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    The magnitude of the electric field due to a charge q is E=Kq/r^2. Remember it also has a direction you need to find. I don't know how you could find a force. What value are you using for the charge at the midpoint? And I'll say this once more, "huge huge number" doesn't mean anything informative. Show your numbers. What you put in, what formulas you put it into and what you got.
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