Question

Consider a copper wire of length $L$, cross-sectional area $A$. It has $n$ numbers 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. $\frac{I}{n^{2}eLA}$

Answer 1

The correct option is C $\frac{I}{neA}$

Lets,

$L=$ length of copper wire

$A=$ cross-sectional area

$n=$ number of free electron per unit volume

$V_d=$ drift velocity of electron

The current flowing in the copper wire,

$I=neA{V}_d$

$V_d=\frac{I}{neA}$

The correct option is C.