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 Φ 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 Φs = 4.5×105 N⋅m2/C. What are (a) the charge of the central particle and the net charges of (b) shell A and (c) shell B? (a) (b) (a) Number Units C (b) Number Units (c) Number Units