Physics (AS & A Level) · Oct / Nov 2020 · Paper 11 · Question 32

Free electrons flow along a copper wire X of radius 5.0 × 10⁻⁵ m with an average drift speed of 2.8 × 10⁻² m s⁻¹. The current in the wire is 3.0 A. There is a current of 2.0 A in a copper wire Y of radius 1.0 × 10⁻⁴ m. What is the average drift speed of the free electrons in copper wire Y?

1. A4.7 × 10⁻³ m s⁻¹
2. B9.3 × 10⁻³ m s⁻¹
3. C1.1 × 10⁻² m s⁻¹
4. D1.9 × 10⁻² m s⁻¹

As printed in the paper