A germanium slice with cross-sectional area $1.0\,\text{cm}^2$ carries a current of $56\,\mu\text{A}$. The charge-carrier number density in the germanium is $2.0 \times 10^{13}\,\text{cm}^{-3}$. Each charge carrier has a charge equal to that of an electron. What is the mean drift velocity of the charge carriers in the germanium?
- A$0.18\,\text{m s}^{-1}$
- B$18\,\text{m s}^{-1}$
- C$180\,\text{m s}^{-1}$
- D$1800\,\text{m s}^{-1}$