Physics (AS & A Level) · Oct / Nov 2024 · Paper 13 · Question 32

A wire of diameter d is connected into an electric circuit. There is a current I in the wire and the charge carriers have an average drift speed v. The wire is replaced with a new wire of the same material but with a diameter 0.5d. The current is adjusted so that the charge carriers in the new wire have an average drift speed 3v. What is the current in the new wire?

1. A0.75I
2. B1.5I
3. C6I
4. D12I

As printed in the paper