# Homework Help: Resistance of the insulation in coaxial cable

1. Nov 12, 2013

### rupesh57272

1. The problem statement, all variables and given/known data
Determine the resistance of the insulation in a length l of coaxial cable.inner radius = a and outer radius= b.

2. Relevant equations

R=$\rho$$\frac{l}{A}$
Area= $\pi$ $(b^2 - a^2)$

3. The attempt at a solution
I calculated the area between the two concentric 'circle' with radius 'a' and 'b'.

Then I calculated R using the formula.

However I am not sure whether it is correct approach or not

Last edited: Nov 12, 2013
2. Nov 12, 2013

### Staff: Mentor

I believe you will need to do an integration instead. The value of A is changing with radius...