3. The capacitors in the circuit shown in the figure below are initially uncharged. (15 pts) a) Calculate the initial value of the battery current when the switch 8 is closed? b) Calculate the battery current after switch S has been closed for a long time. 0) Calculate the final charges on the capacitors. 4. Two concentric spherical conducting shells are separated by vacuum. The inner shell has total charge +0 and outer radius 'a' and the outer shell has charge Q and inner radius 'b' a) Find the capacitance of this spherical capacitor. (5 pts) b) If the region between the spherical shells is lled with silicon with resistivity p = 2300 Q m, find the resistance between the shells assuming a = 100m and b = 30 cm. (5 pts)