Two plates are being discharged by a constant current. Each plate has a radius of 4.00 cm. During the discharging, at a point between the plates at radial distance 2.00 cm from the central axis, the magnetic field has a magnitude of 14.5 nT.
(a) What is the magnitude of the magnetic field at radius 6.20 cm? nT
(b) What is the current in the wires attached to the plates? mA