A copper wire of radius carries a steady current of

PHYSICS · Single correct · A Level · Physics · Electricity · Electricity

Problem

A copper wire of radius

1\,\text{mm}

carries a steady current of

5\,\text{A}

. Given number density of free electrons in copper

n = 8.5 \times 10^{28}\,\text{m}^{-3}

and electronic charge

e = 1.6 \times 10^{-19}\,\text{C}

, calculate the drift velocity of electrons in the wire. (a)

3.7 \times 10^{-4}\,\text{m s}^{-1}

(b)

1.2 \times 10^{-6}\,\text{m s}^{-1}

(c)

1.2 \times 10^{-4}\,\text{m s}^{-1}

(d)

1.2 \times 10^{-2}\,\text{m s}^{-1}