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Homework Help: Gauss's law; large sheet

  1. Feb 8, 2009 #1
    1. The problem statement, all variables and given/known data

    Two very large, nonconducting plastic sheets, each 10.0 cm thick, carry uniform charge densities [tex]\sigma[/tex]1, [tex]\sigma[/tex]2, [tex]\sigma[/tex]3, & [tex]\sigma[/tex]4 on their surfaces, as shown in the figure .


    These surface charge densities have the values [tex]\sigma[/tex]1= -6.00E-6 C/m^2, [tex]\sigma[/tex]2= +5.00E-6 C/m^2,[tex]\sigma[/tex]3= +2.00E-6 C/m^2, and [tex]\sigma[/tex]4= +4.00E-6 C/m^2.

    A) Use Gauss's law to find the magnitude of the electric field at the point A, 5.00 cm from the left face of the left-hand sheet.

    2. Relevant equations

    Gauss's Law

    3. The attempt at a solution

    Well, at first this confused me because I'm pretty sure I remember that in Gauss's law, electric field depends only on the enclosed charge. But this problem gives me a lot of distances. So I guess the formula

    E = [tex]\sigma[/tex]/(2*[tex]\epsilon[/tex]0 )

    doesn't work. That's what I tried, anyway, and got the wrong answer. So, how do I approach a problem like this?
  2. jcsd
  3. Feb 8, 2009 #2
    Okay, I changed the problem.
    Last edited: Feb 8, 2009
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