STANDARD Physics Electromotive Force MCQ Question
When a current of 2 A flows in a battery from negative to positive terminal, the potential difference across it is 12 V. If a current of 3 A flowing in the opposite direction produces a potential difference of 15 V, the emf of the battery is
12.6 V
13.2 V
13.5 V
14.0 V
Correct Answer
Detailed Explanation
Let ε be the emf and r be the internal resistance. From the equations 12 = ε - 2r and 15 = ε + 3r, solving these gives ε = 13.2 V.
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