Physics (AS & A Level) · Oct / Nov 2017 · Paper 13 · Question 33

The number density of conduction electrons in copper is 8.0 × 10^28 m^–3. What is the average drift speed of electrons in a copper wire of diameter 0.42 mm when the current in the wire is 0.57 A?

1. A$8.0 \times 10^{-11}\,\mathrm{m\,s^{-1}}$
2. B$3.2 \times 10^{-10}\,\mathrm{m\,s^{-1}}$
3. C$8.0 \times 10^{-5}\,\mathrm{m\,s^{-1}}$
4. D$3.2 \times 10^{-4}\,\mathrm{m\,s^{-1}}$

As printed in the paper