Q12:A battery with emf e and no internal resistance sup- plies current to the circuit shown in Figure P28.11. When the double-throw switch S is open as shown in the figure, the current in the battery is I0. When the switch is closed in position a, the current in the bat- tery is Ia. When the switch is closed in position b, the current in the battery is Ib. Find the resistances
(a) R1,
(b) R2, and
(c) R3.