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Homework Help: Finding magnitude of new electric fields

  1. Jul 9, 2012 #1
    1. The problem statement, all variables and given/known data

    In Fig. 22-31 the four particles are fixed in place and have charges q1 = q2 = 3e, q3 = 2e, and q4 = -10e. Distance d = 5.42 μm. What is the magnitude of the net electric field at point P due to the particles?

    2. Relevant equations
    E=1/(4πε0) x [ q4/2d^2-q3/d^2] j

    =1/(4πε0) X [(10q/4d)^2- (2q/d^2)

    3. The attempt at a solution

    my work is above and i got 1.53 x 10^20 which is wrong and i have no idea where i went wrong! i followed the student solution manual!
  2. jcsd
  3. Jul 9, 2012 #2


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    Science Advisor
    Homework Helper

    hi wbetting! :smile:

    (try using the X2 and X2 buttons just above the Reply box :wink:)
    is this a square? where is P?

    why is there no q1 or q2 in your equations?

    and why do your equations look like scalar equations when the electric field is a vector? :confused:

    show us your full calculations, and then we'll see what went wrong, and we'll know how to help! :smile:
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