Final answer:
Using Gauss's Law, for spherical shells with charges Q and -Q, the electric field (E) inside the inner shell is 0; between the shells and outside the outer shell, E is given by kQ/r², as if the charge were at the center.
Step-by-step explanation:
To answer the question on determining the electric field in various regions around concentric conducting spherical shells carrying charges Q and -Q, we use the principle of superposition along with Gauss's Law for electricity.
First, it's essential to set up a Gaussian surface appropriate to the symmetry of the problem, which in this case is a sphere concentric with the given charged spherical shells.
Note that for all regions outside the innermost shell, we use the fact that the electric field caused by a spherically symmetric charge distribution is equivalent to if all the charge were concentrated at the center: hence, the use of the inverse square law expression kQ/r² for E.