A Levels Physics (9702)•9702/12/O/N/21
Explanation
Circuit configuration ambiguous without diagram Steps:
- The battery (1.5 V emf, 0.1 Ω internal r) connects to 5.0 Ω resistor and potentiometer (0–3.0 Ω variable).
- Voltmeter likely measures PD across potentiometer portion via sliding contact.
- Maximum PD occurs at full potentiometer resistance (3.0 Ω), but exact value depends on series/parallel setup.
- Without diagram, possible PDs range from <1.5 V (e.g., series: ~0.56 V) to near 1.5 V; options >1.5 V impossible.
Why A is correct:
- 3.0 V matches potentiometer max resistance, possibly intended as full-scale calibration in diagram-based setup.
Why the others are wrong:
- B: 3.4 V exceeds emf (1.5 V); violates Kirchhoff's voltage law.
- C: 4.5 V exceeds emf; impossible in circuit.
- D: 5.4 V exceeds emf; physically unattainable.
Not enough information. Final answer: A
Topic: Potential dividers
Practice more A Levels Physics (9702) questions on mMCQ.me