Two cylindrical rods of uniform cross-sectional area A and 2 A, having free electrons per unit volume 2 n and n respectively are joined in series. A current I flows through them in steady state. Then the ratio of drift velocity of free electrons vL in left rod to drift velocity of electrons in the right operatornamerod vR is

Question

Two cylindrical rods of uniform cross-sectional area A and 2 A, having free electrons per unit volume 2 n and n respectively are joined in series. A current I flows through them in steady state. Then the ratio of drift velocity of free electrons vL in left rod to drift velocity of electrons in the right operatornamerod vR is (A) (1/2) (B) 1 (C) 2 (D) 4

Tardigrade Admin · Accepted Answer

Since current I=n e A v d through both rods is same, ∴ 2(n) e A vL=n e(2 A) vR or (vL/vR)=1

$\frac{1}{2}$

1

2

4

Since current $I = n e A v d$ through both rods is same,
$∴ 2 (n) e A v_{L} = n e (2 A) v_{R}$ or $\frac{v _{L}}{v _{R}} = 1$

21​

1

2

4

Since current I=neAvd through both rods is same, ∴2(n)eAvL​=ne(2A)vR​ or vR​vL​​=1

$\frac{1}{2}$

Since current $I = n e A v d$ through both rods is same,
$∴ 2 (n) e A v_{L} = n e (2 A) v_{R}$ or $\frac{v _{L}}{v _{R}} = 1$