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Homework Help: Parallel Plates

  1. Feb 4, 2007 #1
    1. The problem statement, all variables and given/known data

    An infinite plane of charge with surface charge density sigma = 8.00 nC/m^2 lies in the yz plane at the origin, and a second infinite plane of charge with surface charge density sigma = -8.00 nC/m^2 lies in a plane parallel to the yz plane at x = 4.00 m. The electric field at x = 3.50 m is approximately



    a.226 N/C
    b.339 N/C
    c.904 N/C
    d.452 N/C
    e.zero



    2. Relevant equations

    E = sigma/epsilon_0 for oppositely charged parallel plates

    3. The attempt at a solution
    E = sigma/epsilon_0 = (8.00*10^-9 C/m^2)/(8.85*10^-12) = 904 N/C ???


    1. The problem statement, all variables and given/known data

    An infinite plane of charge with surface charge density sigma = 8.00 nC/m^2 lies in the yz plane at the origin, and a second infinite plane of charge with surface charge density sigma = -8.00 nC/m^2 lies in a plane parallel to the yz plane at x = 4.00 m. The electric field at x = 5.00 m is approximately

    a.226 N/C
    b.339 N/C
    c.904 N/C
    d.452 N/C
    e.zero


    2. Relevant equations

    See below.

    3. The attempt at a solution

    If one draws a diagram for the E (and F) vectors, the vectors cancel each other out when outside the space between the plates, so it is 0?

    Thanks.
     
  2. jcsd
  3. Feb 4, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    It's all good. (I didn't check your arithmetic for the first one, but your method is correct.)
     
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