An infinite wire oriented in the z direction has a cross-sectional current density .J. In other words, I = f J-dA. For this problem, take J = [(21,)/(wa2)] (1 = (r/a)?) 2 for r a, where a is the radius of the wire, r is the radial distance from the wire axis, and [ i1s the total current. Use Ampere to figure out the following... a) The total current passing through the entire cross-section of the wire. b) The magnitude of the magnetic field B outside of the wire at some radius r > a? ) The current I contained in a circular cross-section of radius r