JEE MAIN - Physics (2023 - 31st January Morning Shift - No. 6)
The drift velocity of electrons for a conductor connected in an electrical circuit is $$\mathrm{V}_{\mathrm{d}}$$. The conductor in now replaced by another conductor with same material and same length but double the area of cross section. The applied voltage remains same. The new drift velocity of electrons will be
$$\frac{V_{d}}{4}$$
$$\mathrm{V}_{\mathrm{d}}$$
$$2 \mathrm{~V}_{\mathrm{d}}$$
$$\frac{V_{d}}{2}$$
Explanation
Drift velocity of electron, $V_d=\frac{-e E \tau}{m}$
As $E=\frac{V}{l}$
We can write, $V_d=\frac{-e V\tau}{m l}$
where, $l=$ length of conductor,
$V$ is applied voltage
As drift velocity does not depends upon area, so it will remain same, even after changing area of conductor.
As $E=\frac{V}{l}$
We can write, $V_d=\frac{-e V\tau}{m l}$
where, $l=$ length of conductor,
$V$ is applied voltage
As drift velocity does not depends upon area, so it will remain same, even after changing area of conductor.
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