Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: What is the magnitude and direction of the electric field

  1. May 18, 2007 #1
    What is the magnitude and direction of the electric field at a point midway between a -7.0 µC and a +6.0 µC charge 2.5 cm apart? Assume no other charges are nearby.

    I thought I was approaching the problem correctly, but I'm not getting the right answer. I used the equation:
    E = k(Q1 + Q2)/L^2
     
  2. jcsd
  3. May 18, 2007 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Hard to say what went wrong. What's L?
     
  4. May 18, 2007 #3
    L is 2.5 cm
     
  5. May 18, 2007 #4

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    How far is the point midway between the charges from each charge? That's what should go into your E expression.
     
  6. May 18, 2007 #5
    drawin it all might help, as it always does =P
     
  7. May 18, 2007 #6

    hage567

    User Avatar
    Homework Helper

    Make sure all your units are consistent too.
     
  8. May 18, 2007 #7

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    It's better than plugging numbers randomly into formulas just because they happen to be stated in the problem.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook