# Potential of a Charged Cylinder

1. Nov 5, 2007

### aliaze1

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

A hollow cylinder of radius r and height h has a total charge q uniformly distributed over its surface. The axis of the cylinder coincides with the z axis, and the cylinder is centered at the origin, as shown in the figure.

What is the potential V0 in the limit as h goes to zero?

2. Relevant equations

http://photo.ringo.com/240/240690564O546905961.jpg [Broken]

3. The attempt at a solution

with h=0, the values under the root would be 1 (1+0), and the other values in the parenthesis would be zero, so we would have ln(1) which is 0, and then 0 multiplied times the rest would also be 0, but this is incorrect.

Thanks in advance for the help!

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2. Nov 5, 2007

### Chi Meson

Where is Vo to be measured? On the surface I assume? And as h goes to zero, this becomes simply a circular charge distribution, doesn't it?

3. Nov 5, 2007

### Midy1420

to perform that limit use l'hospitals rule from calculus. and like the previous states you need a reference point to calculate potential is it in the center or is it along the z axis