Consider a conducting hollow sphere, A, with internal radius R and external radius R2. Con- sider then a second sphere, B, also conducting (but full this time), with radius R3. The two spheres are assumed to be very far from each other and connected by a conducting wire with negligible cross-section. A third conducting sphere, D, with radius R < R is located inside the inner cavity of the first sphere, concentric with that sphere (cf. Fig. HA5.1). The third conducting sphere is charged with charge q. Calculate the potential on the third conducting sphere (with radius Ro) in conditions of macroscopic electrostatic equilibrium. [Hint: Use the capacitance calculated in problem HA 5.2. If you did not solve that problem, the capacitance of two concentric conducting spheres with radii a (internal) and b (external) and charge qa = -q (on the internal sphere) and q = +q (on the external sphere) is given by ] C = 4O b. ab - a TR RDA R3 CDB