A metal sphere with radius ra = 1.30cm is supported on an insulating stand at the center of a hollow, metal, spherical shell with radius rb = 9.90cm . Charge +q is put on the inner sphere and charge ?q on the outer spherical shell. The magnitude of q is chosen to make the potential difference between the spheres 480V , with the inner sphere at higher potential.

Part A

Calculate q.
q =C