Asteady current i flows through a wire of radius a. the current density in a wire varies with r as j = kr2, where k is a constant and r is the distance from the axis of the wire. find expressions for the magnitudes of the magnetic field inside and outside the wire as a function of r. (hint: find the current through an ampèrian loop of radius r using ithru = j · da. use the following as necessary: μ0, a, i and r. do not substitute numerical values; use variables only.)