The space between two concentric conducting spherical shells of radii b = 1.70 cm and a = 1.20 cm is filled witha substance of dielectric constant κ = 20.8. A potentialdifference V = 15.0 V is applied across the inner andouter shells. Determine (a) the capacitance of the device, (b) the free charge q (in C) on the inner shell, and (c) the charge q (inC) induced along the surface of the inner shell.