Copper Drift Velocity

Electricity and Magnetism Level 2

A copper wire of resistivity $1.8 \times 10^{-8} \:\Omega\cdot\text{m}$ and length $L = 1 \text{ m}$ is connected to either terminal of a $1.5 \text{ V}$ battery. If the density of conduction electrons is $3 \times 10^{29} \text{ m}^{-3}$ , find the drift velocity of the conduction electrons in millimeters per second.

0.89

1.73

2.41

3.22

1 solution

Matt DeCross
May 10, 2016

Relevant wiki: Ohm's Law (Microscopic Interpretation)

The drift velocity is given by the formula:

$v = \frac{V}{\rho L e n_e}.$

Since all quantities are given, one can just plug in:

$v = \frac{1.5 \text{ V}}{1.8 \times 10^{-8} \Omega \cdot \text{m} \times 1 \text{ m} \times 1.6\times 10^{-19} \text{ C} \times 3 \times 10^{29} \text{ m}^{-3}} \approx 1.73 \text{ mm}/\text{s}.$

Copper Drift Velocity

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