(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

[PLAIN]http://smartphysics.com/images/content/EM/03/h3_lineF.png [Broken]

A cylinder of radius a = 6.1 cm and height h = 9.7 cm is aligned with its axis along the y-axis. An infinite line of charge is placed at x=3.05cm where λ1 = -2 μC/cm and λ2 = 6 μC/cm at x=-3.05 cm. Point P is located at x = 6.1 cm.

What is the value for Ex(P), the x-component of the electric field at point P?

2. Relevant equations

[itex]\int E\cdot dA = Q_{enc}/\epsilon_o[/itex]

3. The attempt at a solution

I have calculated the Qenc which I think should just be λ1 + λ2 = 4E-4 C/m, and the radius of my gaussian surface is just .0305 m. So I try E = [(λ1 + λ2)/ (2pi(8.85E-12)(.0305)] and that didn't work. I also tried to take each charge separately and calculate it based on their individual radius' if you were to take the gaussian surface looking at just λ1 and then λ2 but this isn't working for me either. I'm confused because I thought that you just have to calculate the Qenclosed, and both charges are enclosed in the cylinder and you just have to calculate the gaussian surface with respect to the radius that you want your point to be enclosed in. A little insight and help would be much appreciated! Thanks.

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# Homework Help: Infinite lines of charge, Gauss' Law

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