Physics (AS & A Level) · Oct / Nov 2021 · Paper 11 · Question 38

Potential differences across two resistors of resistances R1 and R2 are compared using a potentiometer wire (uniform resistance wire) in the electrical circuit shown. One terminal of a galvanometer is connected to point X. The galvanometer reads zero when its other terminal is connected to a point that is a distance of 60 cm from one end of the potentiometer wire. One terminal of a second galvanometer is connected to point Y. This galvanometer reads zero when its other terminal is connected to a point that is a distance of 80 cm from the same end of the potentiometer wire. What is the ratio R2/R1?

1. A1/3
2. B3/4
3. C3/1
4. D4/3

As printed in the paper