A spherical conductor of radius a = 1.5 cm with a charge Q = -20 nC. At the center of the conductor sphere is a hollow insulator sphere whose inner radius is b= 2 cm and outer radius is c = 3 cm (see picture). This insulating ball is given a charge of q = + 30 nC. Using Gauss's law, determine the location of the points where the electric field is zero!

A spherical conductor of radius a = 1.5 cm with a charge Q = -20 nC. At the center of the conductor sphere is a hollow insulator sphere whose inner radius is b= 2 cm and outer radius is c = 3 cm (see picture). This insulating ball is given a charge of q = + 30 nC. Using Gauss's law, determine the location of the points where the electric field is zero!