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Homework Help: Electric Field GRE Problem

  1. Sep 5, 2013 #1
    1. The problem statement, all variables and given/known data

    I'm confused. How can there be a charge density if the electric field is one dimensional?
  2. jcsd
  3. Sep 5, 2013 #2
    Think about charged sheets. What would be the electric field because of a charged sheet that is infinite in size?
  4. Sep 6, 2013 #3
    so there is an electric field through e_x and e_y but it comes from the e_z field? like it says e_x and e_y are zero but say there was a point (1,0,0) (x,y,z). The "sheet" in the field would make there be an electric field in the x?

    I don't know if i'm saying what i'm thinking clearly. I mean it looks the problem states that there is NO E field in the x and y domains, and yet if there is an E field in the Z domain, there can still be an E field in the X and Y because it is a distance r away from the Z. Dig?
  5. Sep 13, 2013 #4
    What if the sheet of charge is in the x-y plane and is infinite?
  6. Sep 13, 2013 #5
    The "domain" is a region of space. There are no ex and ey domains.
    Every point in the domain has coordinates x,y,z. The field is all along the z direction, in every point.
    The field lines are all parallel to each other and to the z axis.
    Te magnitude of the field changes linearly along the z axis.

    Yous just need to see if this field can satisfy Maxwell's equations, and if it can, in what conditions.
  7. Sep 13, 2013 #6
    Sorry about my previous reply. There was power shortage in my area. Ignore that reply completely. Try calculating the charge density in such a space. It weirdly turns out to be a constant. This means there is a uniform charge distribution throughout the space. I really don't think you can go in the reverse direction (assuming a uniform charge distribution in space and finding the field proportional to z). This seems very weird. The only positive thing here is that there does exist a charge density.
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