# Homework Help: Concentric Cylindrical Conducting Shells Potential Difference

1. Sep 20, 2010

### jeff24

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

An infiinitely long solid conducting cylindrical shell of radius a = 4.5 cm and negligible thickness is positioned with its symmetry axis along the z-axis as shown. The shell is charged, having a linear charge density λinner = -0.35 μC/m. Concentric with the shell is another cylindrical conducting shell of inner radius b = 17.1 cm, and outer radius c = 20.1 cm. This conducting shell has a linear charge density λ outer = 0.35μC/m.

https://www.physicsbrain.com/images/content/EM/08/h8_cylinder.png

What is V(c) – V(a), the potential difference between the the two cylindrical shells?

2. Relevant equations

$$\Delta V = V_b - V_a = \frac{{\Delta U}}{{q_0 }} = - \int_a^b {E \cdot d\ell }$$

V(c)-V(a) = -integral from A to C of the Electric Field dot dl

3. The attempt at a solution

I don't know where to start. I don't even know how to get the electric field or charge of a 3-D object (outer cylindrical shell) when I'm only given lambda, charge/meter.

Last edited by a moderator: Apr 25, 2017
2. Sep 21, 2010

### Thaakisfox

Use Gauss's law to get the electric field.