The number density of free electrons in copper is nearly 8 × 1 0 28 m − 3 . A copper wire has its area of cross-section = 2 × 1 0 − 6 m 2 and is carrying a current of 3.2 A . The drift speed of the el

Question

The number density of free electrons in copper is nearly 8 × 1 0 28 m − 3 . A copper wire has its area of cross-section = 2 × 1 0 − 6 m 2 and is carrying a current of 3.2 A . The drift speed of the electrons is _____ × 1 0 − 6 m s − 1 .

TestHub · Accepted Answer

The formula to calculate the current through any conductor is given by
$I = n A e v_{d} ... (1)$
Substitute the values of the given parameters into equation (1) and solve to calculate the required drift velocity of the electrons.
$3.2 = 8 \times 1 0^{28} \times 2 \times 1 0^{- 6} \times 1.6 \times 1 0^{- 19} \times v_{d} \Rightarrow = 125 \times 1 0^{- 6} m s^{- 1} v_{d} = \frac{3.2}{16 \times 1.6 \times 1000} m s^{- 1}$

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