Physics (AS & A Level) · Oct / Nov 2019 · Paper 12 · Question 35

A battery has an electromotive force (e.m.f.) $E$ and internal resistance $r$. The battery delivers a current $I$ to a variable resistor and the potential difference (p.d.) across its terminals is $V$. The variable resistor is adjusted so that $I$ increases. Why does $V$ decrease?

1. AThe e.m.f. $E$ decreases.
2. BThe internal resistance $r$ increases.
3. CThe p.d. across $r$ increases.
4. DThe resistance of the variable resistor increases.

As printed in the paper