# NEET Physics Current Electricity Questions Solved

The drift velocity of free electrons in a conductor is ‘v’ when a current ‘i’ is flowing in it. If both the radius and current are doubled, then drift velocity will be

(1) v

(2) $\frac{v}{2}$

(3) $\frac{v}{4}$

(4) $\frac{v}{8}$

(2) ${v}_{d}=\frac{i}{ne\pi {r}^{2}}⇒{v}_{d}\propto \frac{i}{{r}^{2}}⇒\frac{v}{v\text{'}}=\frac{{i}_{1}}{{i}_{2}}×{\left(\frac{{r}_{2}}{{r}_{1}}\right)}^{2}$

$⇒\text{\hspace{0.17em}\hspace{0.17em}}v\text{'}=\frac{v}{2}$.

Difficulty Level:

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