Physics (AS & A Level) · Oct / Nov 2022 · Paper 12 · Question 37

A potential divider circuit is designed to detect the difference in temperature between two different places. The cell has electromotive force (e.m.f.) 20 mV and negligible internal resistance. Initially, thermistors X and Y are at the same temperature and have the same resistance. The voltmeter reads 10 mV. X is then placed in a cold environment and its resistance doubles. Y is placed in a warm environment and its resistance halves. What is the new reading on the voltmeter?

1. A4 mV
2. B5 mV
3. C15 mV
4. D16 mV

As printed in the paper