A metal sphere with radius ra = 1.20 cm is supported on an insulating stand at the center of a hollow, metal, spherical shell with radius r b = 9.60 cm. 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 500 V, with the inner sphere at higher potential.
(a) Use the result of Exercise 23.49(b) to calculate q.
(b) With the help of the result of Exercise 23.49(a), sketch the equipotential surfaces that correspond to 500. 400, 300. 200, 100. and 0 V.
(c) In your sketch, show the electric field lines. Are the electric field lines and equipotential surfaces mutually perpendicular? Are the equipotential surfaces closer together when the magnitude of E is largest?