A Conductor wire having $10^{29} $ per electron per $m^3$ carries a current of 20A.If the crosssection of wire is $1 mm^2$, then drift velocity of the electron will be ($ e = 1.6 \times 10^{-19} C$)
Answer & explanation
Correct answer: option 2
$ I = nA V_de$
$\Rightarrow V_d = \frac{I}{nAe} = \frac{20}{10^{29}\times 10^{-6} \times 1.6 \times 10^{-19}} = 1.25\times 10^{-3}m/s$