The space between two concentric conducting spherical shells of radii b = 2.40 cm and a = 1.20 cm is filled with a substance of dielectric constant ? = 13.1. A potential difference V = 89.0 V is applied across the inner and outer shells. Determine (a) the capacitance of the device, (b) the free charge q (in C) on the inner shell, and (c) the charge q (in C) induced along the surface of the inner shell.