Physics

Problem

A copper wire of cross-sectional area

1 \times 10^{-6} \text{ m}^2

carries a current of 1 A. The free electron number density of copper is about

10^{29} \text{ m}^{-3}

. The charge on an electron is of the order of

10^{-19} \text{ C}

. What is the best estimate for the speed at which the electrons move along the wire? a.

10^{-4} \text{ ms}^{-1}

1 \text{ ms}^{-1}

100 \text{ ms}^{-1}

10^4 \text{ ms}^{-1}