A current i is flowing through the wire of diameter d having drift velocity of electrons vd in it. What will be new drift velocity when diameter of wire is made d / 4 ?

Question

A current i is flowing through the wire of diameter d having drift velocity of electrons vd in it. What will be new drift velocity when diameter of wire is made d / 4 ? (A) 4 Vd (B) (Vd/4) (C) 16 Vd (D) (Vd/16)

Tardigrade Admin · Accepted Answer

I = nAeVd Now I is constant Vd propto(1/A) If diameter of wire is (d/4) then area is (1/16) times so new drift velocity = 16 Vd

Q. A current $i$ is flowing through the wire of diameter $d$ having drift velocity of electrons $v_{d}$ in it. What will be new drift velocity when diameter of wire is made $d /4$ ?

$4 V_{d}$

$\frac{V _{d}}{4}$

$16 V_{d}$

$\frac{V _{d}}{16}$

I = nAeV_d
Now I is constant
$V_{d} \propto \frac{1}{A}$
If diameter of wire is $\frac{d}{4}$ then area is $\frac{1}{16}$
times so new drift velocity = 16 V_d

Q. A current i is flowing through the wire of diameter d having drift velocity of electrons vd​ in it. What will be new drift velocity when diameter of wire is made d/4 ?

4Vd​

4Vd​​

16Vd​

16Vd​​