A small conducting spherical shell with inner radius a and outer radius b is concentric with a larger conducting spherical shell with inner radius c and outer radius d. The inner shell has a total charge of -1q and the outer shell has a total charge of +3q. Select True or False for the following statements. The total charge on the outer surface of the large shell is +2q. The electric field in the region r > d is zero. The total charge on the inner surface of the small shell is -4q. The electric field in the region c < r < d is zero. The total charge on the inner surface of the large shell is zero. The total charge on the outer surface of the small shell is -1q. The electric field in the region r < a is zero. Use Gauss's Law.
Explanation / Answer
All questions are simple ... if you study. EDIT: In this case, here is help. The whole set of questions is based on Gauss' theorem and the fact that inside a conductor the electric field is zero. Look these up in your son's textbook or Wikipedia. So, the field inside the metal part of each shell is zero. Now start with a spherical Gaussian surface centered in the inner shell and of radius just short of a. There is no charge contained in this Gaussian surface, so the electric field is 0. Next, expand the Gaussian to a radius between a and b: you are now inside the inner metal shell. Since this is a conductor, the electric field field is 0. Now let the Gaussian surface expand to a radius >b and