Physics (AS & A Level) · May / June 2022 · Paper 12 · Question 37

A potentiometer circuit is used to determine the electromotive force (e.m.f.) E_X of a cell. The circuit includes a second cell of known e.m.f. E_0 and negligible internal resistance, and a uniform resistance wire PQ of known length. E_X is less than E_0. The movable connection J can be positioned anywhere along the length of the resistance wire. Which circuit is suitable for determining E_X?

1. ACircuit A
2. BCircuit B
3. CCircuit C
4. DCircuit D

As printed in the paper