A charged particle is held at the center of two concentric conducting spherical shells. Figure (a) shows a cross section. Figure (b) gives the net flux @ through a Gaussian sphere centered on the particle, as a function of the radius r of the sphere. The scale of the vertical axis is set by @s = 6.0 x 105 N.m2/C. What are (a) the charge of the central particle and the net charges of (b) shell A and (c) shell B? B (10' N . mz/C) -20 (a) (b) (a) Number Units (b) Number i Units (c) Number i Units