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8. A solid insulating sphere of radius a carries a net positive charge 30, uniformly distributed throughout its volume. Concentric with this sphere is a conducting spherical shell with inner radius b and outer radius c, and having a net charge -O, as shown in the figure below. (a) Construct a spherical Gaussian surface of radius /> c and find the net charge enclosed by this surface. (b) What is the direction of the electric field at r> c? (c) Find the electric field at /2 c. (d) Find the electric field in the region with radius / where c>r > b. (e) Construct a spherical Gaussian surface of radius r , where c > >b, and find the net charge enclosed by this surface. (f) Construct a spherical Gaussian surface of radius r, where b > >a, and find the net charge enclosed by this surface. (g) Find the electric field in the region b - rza. (h) Construct a spherical Gaussian surface -Q of radius r