A current of 5 A is passing through a metallic wire of cross-sectional area 4 × 10^ -6 ~m^2 . If the density of charge carriers of the wire is 5 × 10^ 26 ~m^ -3 , then the drift velocity of the electrons will be

Correct answer: B. 1.56 × 10^ -2 ~m / s Drift velocity, v_d=(1)/(n e A) v_d= 5 (5 × 10^ 26 ) ×(1.6 × 10^ -19 ) ×(4 × 10^ -6 ) =(1)/(64)=1.56 × 10^ -2 ~ms^ -1

JIPMER 2011

Exam: JIPMER
Year: 2011
Subject: Physics
Chapter: Current Electricity

JIPMER 2011 · Physics · Current Electricity

A current of 5 A is passing through a metallic wire of...

A current of 5 A is passing through a metallic wire of cross-sectional area

4 \times 10^{-6} \mathrm{~m}^2

. If the density of charge carriers of the wire is

5 \times 10^{26} \mathrm{~m}^{-3}

, then the drift velocity of the electrons will be

Options

A $1 \times 10^2 \mathrm{~m} / \mathrm{s}$
B $1.56 \times 10^{-2} \mathrm{~m} / \mathrm{s}$
C $1.56 \times 10^{-3} \mathrm{~m} / \mathrm{s}$
D $1 \times 10^{-2} \mathrm{~m} / \mathrm{s}$

Correct answer

B. $1.56 \times 10^{-2} \mathrm{~m} / \mathrm{s}$

Step-by-step solution

Drift velocity,

v_d=\frac{1}{n e A}

\Rightarrow v_d=\frac{5}{\left(5 \times 10^{26}\right) \times\left(1.6 \times 10^{-19}\right) \times\left(4 \times 10^{-6}\right)}

=\frac{1}{64}=1.56 \times 10^{-2} \mathrm{~ms}^{-1}

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