# B field inside conductor with assymetric cavity

1. May 14, 2014

### Gauss M.D.

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

Infinite straight conductor, paralell with z axis, of radius R1 with a cylindrical cavity of radius R2. The axis of the cavity passes through the point <0,b,0>. A current I flows through the conductor. The current density is homogenous inside the cundoctor. Find the direction and magnitude of the B-field inside the cavity.

2. Relevant equations

3. The attempt at a solution

I think we're supposed to use

$\oint \textbf{B} \cdot \textbf{dl} = \mu _0 I$

Where we first do the outer line integral, and then subtract the inner line integral.

1) Am I on to something?
2) How do I do the inner line integral in the most convenient way?

2. May 14, 2014