When potential difference across the terminals of a battery is measured using an analogue voltmeter of resistance 95 ohms, the reading on the voltmeter is 5.70 V. When it is measured using a very high resistance digital meter the reading is 6.00 V. What is the internal resistance of the battery?

Answer 1

I = V/Rm = 5.70/95 = 0.06A.

r = V/I = (6-5.7)/0.06 = 0.30/0.06 = 5. Ohms.