The emf of a cell is 1.5 V. When connected to an external resistance, the potential difference drops to 1.2 V. If the current is 0.3 A, what is the internal resistance?
Q1. The emf of a cell is 1.5 V. When connected to an external resistance, the potential difference drops to 1.2 V. If the current is 0.3 A, what is the internal resistance?
Answer: 1 ohm
Explanation: r = (E - V)/I = (1.5 - 1.2)/0.3 = 1 ohm.