1. The problem statement, all variables and given/known data A coaxial conductor has the length L. The inner conductor of radius a carries a current I in the z direction. The outer conductor is very thin and has the radius b. Calculate the total magnetic flux enclosed within the conductors. 2. Relevant equations Magnetic flux around a cylindrical conductor: B_(phi)=(mu_0)*I/(2*pi*r) 3. The attempt at a solution The question really is whether the outer conductor does anything except determine the region where the flux is to be calculated. Is the outer conductor affected at all since the magnetic flux density from the inner conductor isn't changing, and does it then have any effect on the flux?