Physics (AS & A Level) · Oct / Nov 2025 · Paper 12 · Question 35

The diagram shows a circuit with a battery of electromotive force (e.m.f.) 60 V and negligible internal resistance, a 20 kΩ resistor, a thermistor and a voltmeter. The resistance of the thermistor is 20 kΩ. The temperature of the thermistor decreases, and this causes its resistance to change by 50%. After this change, what is the reading on the voltmeter?

1. A20 V
2. B24 V
3. C36 V
4. D40 V

As printed in the paper