CAPE Physics Unit 2 · 2007 · Paper 1 · Question Q4

A wire of diameter 1.0\text{ mm} is carrying a current of 1.5\text{ A}. The charge carriers are electrons and the net drift velocity of the electrons is 0.5\text{ mm s}^{-1}. The number of conduction electrons per unit volume in the conductor is

1. (A)9.6 \times 10^{28}\text{ m}^{-3}
2. (B)2.4 \times 10^{28}\text{ m}^{-3}
3. (C)6.0 \times 10^{23}\text{ m}^{-3}
4. (D)9.5 \times 10^{23}\text{ m}^{-3}