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A current of $2 \mathrm{~A}$ is passing through a metal wire of cross-sectional area $2 \times 10^{-6} \mathrm{~m}^{2}$. If the number density of free electrons in the wire is $5 \times 10^{26} \mathrm{~m}^{-3}$, the drift speed of electrons is (Given, $\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}$ )
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Verified Answer
The correct answer is:
$\frac{1}{80} \mathrm{~ms}^{-1}$
Drift velocity of electrons
$$
\begin{aligned}
v_{\mathrm{d}} &=\frac{\mathrm{I}}{n e A} \\
&=\frac{2}{5 \times 10^{26} \times 1.6 \times 10^{-19} \times 2 \times 10^{-6}}
\end{aligned}
$$
or $\quad \mathrm{v}_{\mathrm{d}}=\frac{1}{80} \mathrm{~ms}^{-1}$
$$
\begin{aligned}
v_{\mathrm{d}} &=\frac{\mathrm{I}}{n e A} \\
&=\frac{2}{5 \times 10^{26} \times 1.6 \times 10^{-19} \times 2 \times 10^{-6}}
\end{aligned}
$$
or $\quad \mathrm{v}_{\mathrm{d}}=\frac{1}{80} \mathrm{~ms}^{-1}$
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