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Breedlove
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Homework Statement
A nonconducting wall carries charge with a uniform denisty of 8.g µC/cm2. What is the electric field 7.00cm in front of the wall? Explain whether your result changes as the distance from the wall is varied.
Homework Equations
I'm still really new, I just registered, and trying to find the integral sign and stuff is proving to be pretty difficult
[tex]\int[/tex]EdotdA=Qenclosed/A
E=k[tex]\frac{q}{r2}r[/tex]unit vector
So Gauss's Law and the equation for the electric field, I think, are relevant. The relationship [tex]\sigma[/tex]=Q/A I think is important too. Let's throw in Coulomb's Law for good measure.
F=kqq0/(r2)r unit vector
The Attempt at a Solution
Okay, so from my understanding of Gouss's Law, you can use it to calculate the electric field around a closed symmetrical surface that surrounds the thing you want to find the electric field of. Rather, Gauss's Law is a way of counting up the electric field lines. I think I understand how to use Gauss's Law to find the electric field at a point around a sphere of charge; you can just make a Gaussian Sphere around it.
Anyway, I guess my major source of confusion is that you can't really encapsulate a wall, like if it was a rod, or if we could interpret it as a long line of charge, then we could put a cylinder around it. I think I gathered from another post that
E=[tex]\sigma[/tex]/(2[tex]\epsilon[/tex]0)
I think that this is the key, but I don't know how this came about. How can this be derived from Gauss's Law or the equation for electric field?
I'm generally pretty confused, and I think I'm going to try to firm up my understanding of applying Gauss's law while I hope that someone replies.