Physics (AS & A Level) · May / June 2023 · Paper 12 · Question 37

In the potentiometer circuit shown, the reading on the ammeter is zero. [potentiometer circuit diagram with power supply, ammeter, sliding contact, uniform metal wire and LDR] The light-dependent resistor (LDR) is then covered and the ammeter gives a non-zero reading. Which change could return the ammeter reading to zero?

1. Adecreasing the supply voltage
2. Bincreasing the supply voltage
3. Cmoving the sliding contact to the left
4. Dmoving the sliding contact to the right

As printed in the paper