If a current of $5.0\,\text{A}$ flows through a copper wire, the mean drift speed of the free electrons is $8.0 \times 10^{-4}\,\text{m s}^{-1}$. What is the mean drift speed in another copper wire that has twice the diameter and a current of $10.0\,\text{A}$?
- A$4.0 \times 10^{-4}\,\text{m s}^{-1}$
- B$8.0 \times 10^{-4}\,\text{m s}^{-1}$
- C$1.6 \times 10^{-3}\,\text{m s}^{-1}$
- D$3.2 \times 10^{-3}\,\text{m s}^{-1}$