Question

The number of free electrons per 100 mm of ordinary copper wire is 2 x 1021 . The average drift speed of electrons is 0.25 mm/s. What is the current flowing? *

Answer 1

➮ Question :-

$⟶$The number of free electrons per 100 mm of ordinary copper wire is 2 x 1021 . The average drift speed of electrons is 0.25 mm/s. What is the current flowing?

➮ Given :-

$⟶$Number of electron, n = 2 × 10²¹

$⟶$Average drift speed, 0.25mm/s

➮ To find :-

$⟶$the current flowing

➮ Solution :-

$⟶$$\boxed{\sf Q = ne}$

$⟶$Q = 2 × 10²¹ × 1.6 × ${10}^{ - 19}$

$⟶$Q = 320C

since,

$⟶ S = \frac{D}{T}$

$⟶ T = \frac{D}{S}$

$⟶ T = \frac{10}{0.25} = 40$

so, current

$⟶ I = \frac{Q}{T}$

$⟶ I = \frac{320}{4}$

$⟶$ $\boxed{\sf I = 8A}$

hence,the current flowing in copper wire is 8A