A-LevelPhysicsD.C. circuits9702/12 · May/June 2021 · Q361 Mark
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. [Figure 36.1] Which statement explains the change to the reading of the voltmeter as contact Z is moved towards end X of the potentiometer?
This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.
AThe voltmeter reading decreases because the current through the cell decreases.
BThe voltmeter reading decreases because the current through the cell increases.
CThe voltmeter reading increases because the current through the cell decreases.
DThe voltmeter reading increases because the current through the cell increases.
✓ Correct answer
C: The voltmeter reading increases because the current through the cell decreases.
Practise more questions on this topic
Oracle Prep sorts past-paper questions by topic, so you can drill D.C. circuits and see which topics are most likely to come up next.
Sign up free →