1. Electric Flux Consider the charge distribution shown in the figure on the right. The loops are cross sections of closed surfaces labeled S: to S.. Suppose that the only charges in the distribution are the ones shown in the figure. Find the electric flux across (a)S., (b) S:, (c)S:, and (d)S.. -20 30 2. Concentric Insulating Spheres. An insulating solid sphere, of radius a, with a uniform volume charge density p > 0, is placed concentric with an insulating spherical shell, of inner radius a and outer radius b, with a uniform volume charge density-p. Calculate the electric field at a distance r from the common center of the two spheres for (a) 0 b3. Charge Metal Rod. An isolated very long metallic rod with a uniform circular cross section of radius 0.55 mm has a constant charge per unit length of 2.25x 10-3C/m. Find the electric field magnitudes at distances (a) 0.25 mm and (b) 0.75mm, from the longitudinal axis of the rod. 4. Exponentially Decaying Charge Density. A spherically symmetric charge distribution is described by a volume charge density given by p = prettia, where po and a are both positive constants, and r is the distance from the center of the distribution. (a) Determine the electric field at any value of r. (b) Sketch the graph of the electric field magnitude with r. (c) Describe how the electric field varies with the distancer