Resistance of the insulation in coaxial cable

[rupesh57272]

Homework Statement

Determine the resistance of the insulation in a length l of coaxial cable.inner radius = a and outer radius= b.

Homework Equations

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

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

 

[berkeman]

Homework Statement

Determine the resistance of the insulation in a length l of coaxial cable.inner radius = a and outer radius= b.

Homework Equations

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

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

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