13) A battery charger supplies 10 A to charge a storage battery which has an open - circuit voltage of 5.6 V. If the voltmeter connected across the charger reads 6.8V, what is the internal resistance of the battery at this time?
14) A battery of e.m.f. and negligible internal resistance is connected to two resistors of resistances
as shown in the figure. What is the potential difference across the resistor of resistance