A solid insulating sphere of radius 0.06 cm carries a total charge of 30 nC. Concentric with this sphere is a conducting spherical shell with an inner radius of 0.13 cm and an outer radius of 0.17 cm and carrying a total charge of -15 nC. Find the magnitude of the electric field at r = 0.20 cm from the center of the two spheres and shell.

In the figure a sphere, of radius a = 13.2 cm and charge q = 6.00×10-6 C uniformly distributed throughout its volume, is concentric with a spherical conducting shell of inner radius b = 37.0 cm and outer radius c = 39.0 cm . This shell has a net charge of -q. Find expressions for the electric field, as a function of the radius r, within the sphere and the shell (r< a). Evaluate for r=6.6 cm. Find expressions for the electric field as a function of the radius r, between the sphere and the shell (a< r <b). Evaluate for r=25.1 cm. Find expressions for the electric field as a function of the radius r, inside the shell (b< r <c). Evaluate for r=38.0 cm

The figure shows a cross-section of a spherical cavity of radius 11.7 cm at the center of a metal sphere of radius 56 cm. A point charge q = 22.1 nC rests at the center of the cavity and the metal conductor carries no net charge. Determine the magnitude of the electric field at a point 73.6 cm from the center of the cavity. Cavity + q

A non-conducting solid sphere with a radius of 50.0 cm located at the origin has a charge of +3.00 µC spread uniformly throughout its volume. Concentric with the sphere is a conducting spherical shell that has an inner diameter of 2.00 m and an outer diameter of 2.50 m with a net charge of -2.50 µC. Calculate the magnitude and direction (either away or toward the origin) of the electric field at (a) r = 1.20 m, and (b) r = 3.00 m, where r is the distance from the origin. (c) What is the net charge on the inner and outer surfaces of the shell? (d) Include a diagram of the situation indicating both the sphere and the shell along with the Gaussian surfaces.