Question

A current of $5A$ is passing through a metallic wire of cross-sectional area $4\times {10}^{-6}{m}^2$. If the density of charge carriers of the wire is $5\times {10}^{26}{m}^{-3}$, the drift velocity of the electrons will be :

• A. $1\times {10}^{2}m{s}^{-1}$
• B. $1.56\times {10}^{-2}m{s}^{-1}$
• C. $1.56\times {10}^{-3}m{s}^{-1}$
• D. $1\times {10}^{-2}m{s}^{-1}$

Answer 1

Answer: (B)

$1.56\times {10}^{-2}m{s}^{-1}$

Drift velocity, $v_d=\frac{I}{neA}$
$\Rightarrow v_d=\frac{5}{(5\times {10}^{26})\times (1.6\times {10}^{-19})\times (4\times {10}^{-6})}$
$=1.56\times {10}^{-2}m{s}^{-1}$.