Physics (AS & A Level) · May / June 2025 · Paper 11 · Question 37

A cell is connected in series with an ammeter and a variable resistor. A voltmeter is used to measure the p.d. across the variable resistor. The resistance of the variable resistor is varied, and the p.d. and the current are recorded. The graph shows the variation with current of the p.d. across the variable resistor. What is the internal resistance of the cell?

1. A0.050 Ω
2. B1.6 Ω
3. C20 Ω
4. D23 Ω

As printed in the paper