1. The problem statement, all variables and given/known data Consider two infinitely long cylinders with radius a and b and currents: J = (Jo r)/a for r less than a -Jo for a less than r less than b Find the magnetic field in 1) r less than a 2) a less than r less than b 3) r greater than b 2. Relevant equations 3. The attempt at a solution I think I was able to compute the magnetic field for r less than a using Ampere's law H 2 pi r = (the integral from 0 to a of) (Jo r) /a 2 pi r dr the result that I found for H was H = (Jo r squared )/3a In the other cases Im confused about the integration limits and the addition of magnetic fields. How can I find the magnetic field for a less than r less than b, and for r greater than b ? I would appreciate some help, thanks a lot.