Question

Consider a copper wire of length $L$, cross-sectional area $A$. It has $n$ number of free electrons per unit volume. Which of the following is the correct expression of drift velocity of the electrons when the wire carries a steady current $I$?

• A. $\frac{I}{neL}$
• B. $\frac{I}{{{n}^{2}}eL}$
• C. $\frac{I}{neA}$
• D. $\frac{I}{n{{e}^{2}}LA}$

Answer 1

Answer: (C)

$\frac{I}{neA}$

Answer 2

We have, $I=n e A v_{d}$
Drift velocity, $v_{d}=\frac{I}{n e A}$