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Calculating Electric Field due to two point charges.

  1. Aug 11, 2015 #1
    1. The problem statement, all variables and given/known data
    Two points charges.

    q1=2.4e-6 C is located at (0,0)

    q2=-5.7e-6 C is located at (3,0)

    I must calculate the magnitude of the Electric field at (0,0)

    2. Relevant equations
    E=kq/r^2 ; k=9e9

    3. The attempt at a solution
    The electric field at (0,0) due to q2=9e9x(-5.7e-6)/3^2 = -5700N/C

    Next would be to add the electric field at (0,0) due to q1.
    However, I don't know how to calculate the field as distance is r=0 which doesn't work with the formula.

    How do I calculate the electric field due to a point charge AT the point charge?
     
    Last edited: Aug 11, 2015
  2. jcsd
  3. Aug 11, 2015 #2

    Orodruin

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    You don't. Please quote the problem exactly as stated and not your interpretation of it.
     
  4. Aug 11, 2015 #3

    "Consider a system where a charge -5.7-μC is located at x = 3.0-m, y = 0.0-m and another charge +2.4-μC is located at x = 0.0-m, y=0.0-m. Find the magnitude of the electric field at x = 0.0-m, y = 0.0m. "
     
  5. Aug 11, 2015 #4

    Orodruin

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    This is very likely a misprint in the problem statement. It is likely that one of the values of the positions is wrong or, if part of a bigger problem, the field at (0,0) from q2 is what is intended.
     
  6. Aug 11, 2015 #5
    The next part is :In what direction is this electric field orientated, measured in the normal way (anti-clockwise from the x-axis, which is pointing to the right in the above figure)?

    I tried just the field at (0,0) from q2 at got the wrong answer :( Will try and contact my lecturer

    To put it simply is it impossible to determine the electric field from a point charge at the point charge?
     
  7. Aug 11, 2015 #6

    SammyS

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    The answer to this is: NO !
     
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