# Homework Help: Conducting hollow tube

1. Feb 11, 2009

### jimbo71

1. The problem statement, all variables and given/known data
A very long conducting tube (hollow cylinder) has inner radius a and outer radius b. It carries charge per unit length + \alpha , where \alpha is a positive constant with units of C/m. A line of charge lies along the axis of the tube. The line of charge has charge per unit length + \alpha .

Calculate the electric field in terms of \alpha and the distance r from the axis of the tube for r<a.
Express your answer in terms of the variables \alpha, r, and constant \epsilon_0.

Calculate the electric field in terms of \alpha and the distance r from the axis of the tube for a<r<b.
Express your answer in terms of the variables \alpha, r, and constant \epsilon_0.

Calculate the electric field in terms of \alpha and the distance r from the axis of the tube for r>b.
Express your answer in terms of the variables \alpha, r, and constant \epsilon_0.

What is the charge per unit length on the inner surface of the tube?

What is the charge per unit length on the outer surface of the tube?

2. Relevant equations
E=(1/4*pi-epsilon_0)(q/R^2)

3. The attempt at a solution
No idea where to start or how to set up problem

2. Feb 11, 2009