Two 1.50-V batteries-with their positive terminals in the same direction-are inserted in series into the barrel of a flashlight. One battery has an internal resistance of 0.260 ?, the other an internal resistance of 0.160 ?. When the switch is closed, a current of 600 mA occurs in the lamp.
(a) What is the bulb's resistance?
(b) What fraction of the chemical energy transformed appears as internal energy in the batteries?