A nichrome wire has a resistance of $15\,\Omega$ and a diameter measuring $3.0\,\text{mm}$. The free-electron number density in nichrome is $9.0 \times 10^{28}\,\text{m}^{-3}$. A potential difference (p.d.) of $6.0\,\text{V}$ is applied across the two ends of the wire. What is the mean drift speed of the free electrons in the wire?
- A$9.8 \times 10^{-7}\,\text{m s}^{-1}$
- B$3.9 \times 10^{-6}\,\text{m s}^{-1}$
- C$6.1 \times 10^{-6}\,\text{m s}^{-1}$
- D$2.5 \times 10^{-5}\,\text{m s}^{-1}$