Microscopic view: A cylindrical copper wire of length $L = 2.0m$ and cross-sectional area $A = 1.0\text{ mm}^2$ is connected to a steady DC voltage source.
If a potential difference of 10 V is applied across the copper wire of length 2.0 m, calculate the drift velocity of free electrons given mobility $\mu = 4.2 \times 10^{-4}m^2\text{V}^{-1}\text{s}^{-1}$.