Q. The potential difference between the terminals of a 6 V battery is 7.2V when it is being charged by a current of 2 A. What is the internal resistance of the battery ?
(a) 0.4Ω
(b) 0.6Ω
(c) 1 Ω
(d) 0.5Ω
Ans: B
Sol.
V = E + Ir
7.2 = 6 + 2 r
2 r = 1.2
r = 0.6 ohm