(b) Suppose you have a cylindrical wire of radius a, where a parallel-plate capacitor is being charged. The gap caused by the capacitor between the wire is an imaginary cylinder with radius a and length d. Current I flows through the wire and charges +Q and -Q accumulate on the parallel plates. [Recall: when charging a capacitor, the energy is stored in the electric field.] What is the magnetic field in this surface? [Hint: Evaluate at s = a.]

(b) Suppose you have a cylindrical wire of radius a, where a parallel-plate capacitor is being charged. The gap caused by the capacitor between the wire is an imaginary cylinder with radius a and length d. Current I flows through the wire and charges +Q and -Q accumulate on the parallel plates. [Recall: when charging a capacitor, the energy is stored in the electric field.] What is the magnetic field in this surface? [Hint: Evaluate at s = a.]