I have two questions that I cannot seem to figure out.(adsbygoogle = window.adsbygoogle || []).push({});

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

1)A uniform electric field E=30 N/C exists parallel to the axis of a square pipe of side length l=5 cm as

shown in the figure. Calculate the total electric flux for the slanted face of the pipe

2) A very long metal rod, radius R, has a uniform surface charge density σ. (a) Ignoring end effects, find

the electric field E at a distance R along the radial direction from the surface of the cylinder. Also draw a

diagram show the cross-section of the cylinder and Gaussian surface in your solution. (b) Find the speed

v such that an electron could travel in a circular orbit about the rod at a distance R from the rod’s

surface.

2. Relevant equations

1) psi= EA cos theta

3. The attempt at a solution

1) EA cos theta = (30 N/C) * (A) cos 30

A = (5.00cm)(w) = (5.00cm)*(5.00cm/cos30) = 0.2887m^2

psi EA = (30 N/C) (0.2887)cos30 = 7.50 m^2/C

I am pretty sure this is incorrect, but this is the closest I can get. Can anyone help me out?

I have no idea how to do #2. If someone could lead me in the right direction I would greatly appreciate it.

Thanks guys,

Jason

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# Homework Help: Finding Electric Flux and Electric Fields

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