Two plates (as in Figure) 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 12.5nT.

(a) What is the magnitude of the magnetic field at radial distance 6.00 cm?

(b) What is the current in the wires attached to the plates?