Physics (AS & A Level) · May / June 2021 · Paper 12 · Question 36

A cell of constant electromotive force (e.m.f.) but with internal resistance is connected to a fixed resistor R using a potentiometer. A voltmeter measures the potential difference (p.d.) between the terminals of the cell. Which statement explains the change to the reading of the voltmeter as contact Z is moved towards end X of the potentiometer?

1. AThe voltmeter reading decreases because the current through the cell decreases.
2. BThe voltmeter reading decreases because the current through the cell increases.
3. CThe voltmeter reading increases because the current through the cell decreases.
4. DThe voltmeter reading increases because the current through the cell increases.

As printed in the paper