# Resistance of a hollow aluminum cylinder

1. Oct 6, 2008

### digitaleyes

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

A hollow aluminum cylinder is 2.50m long and has an inner radius of 3.20 cm and an outer radius of 4.60 cm. Treat each surface (inner, outer, and the two end faces) as an equipotential surface.

At room temperature, what will an ohmmeter read if it is connected between the inner and outer surfaces?

2. Relevant equations

R=4.60cm
r=3.20cm

R=$$\rho$$L/A

and possibly

R=($$\rho$$/2piL)*ln(R/r)

3. The attempt at a solution

Well, the first part of the question (not asked here) was to find the resistance from one end of the hollow cylinder to the other (the faces). I found that: 2.00*10-5 $$\Omega$$s. The problem does not say that the current is flowing radially through the cylinder though, but is that to be assumed for doing this second part? Or not? I plugged everything in to the second equation, but the answer is wrong. Should the resistance be the same as it is from end to end? Is it 0?
*confused*