A long, cylindrical conductor of radius R carries a current I as shown in the figure below. The current density J, however, is not uniform over the cross-section of the conductor but is a function of the radius according to J = br3, where b is a constant.
Find an expression for the magnetic field magnitude B at the following distances, measured from the axis. (Use the following variables as necessary: μ0, r1, r2, b, R .)
(a) r1
(b)r2 > R
