Physics (AS & A Level) · May / June 2022 · Paper 13 · Question 38

A potential divider circuit is formed by connecting a battery of negligible internal resistance in series with two variable resistors, as shown. The variable resistors have resistances R_X and R_Y. V_X is the potential difference (p.d.) across the variable resistor with resistance R_X. R_X and R_Y are both changed at the same time. Which combination of changes must cause V_X to increase?

1. AR_X larger, R_Y larger
2. BR_X larger, R_Y smaller
3. CR_X smaller, R_Y larger
4. DR_X smaller, R_Y smaller

As printed in the paper