Question

An electric current of 15 A flows in a wire of area of
cross-section 10-5 m 2. Calculate drift velocity of
electrons if the number of electrons per m of the wire
of electric conduction is 8.4 x 1028. Given that charge
on electron is 1.6 × 10-19 C.
[Ans. 1.116 x 10-4 ms-l]​

solve the 3 number Plzzz

Answer 1

Given:

Current in wire,I= 15 A

Area of cross-section of wire,A= 10⁻⁵m²

No. of electrons per unit volume, n= 8.4x10²⁸

Charge on electron,e= 1.6×10⁻¹⁹ C

To Find:

Drift velocity of electrons in given wire

Solution:

We know that,

• Expression of current I in wire is given by

$\pink{\underline{\boxed{\bf{I=neAv_{d}}}}}$

where,

n is no. of electrons per unit volume

e is charge on electron

A is area of cross-section

$\rm{v_{d}}$ is drift velocity of electron

━━━━━━━━━━━━━━━━━━━━━

Let the drift velocity of electron be $\rm{v_{d}}$

So,

$\longrightarrow\rm{I=neAv_{d}}$

$\longrightarrow\rm{15=8.4\times10^{28}\times1.6\times10^{-19}\times10^{-5}\times v_{d}}$

$\longrightarrow\rm{15=13.44\times10^{4}\times v_{d}}$

$\longrightarrow\rm{13.44\times10^{4}\times v_{d}=15}$

$\longrightarrow\rm{v_{d}=\dfrac{15}{13.44\times10^{4}}}$

$\longrightarrow\rm\green{v_{d}=1.116\times10^{-4}\ m/s}$

Hence, the drift velocity of electron is 1.116×10⁻⁴ m/s.