Question

A current of 3.2 mA flows through a conductor. If charge on an electron is −1.6 × 10^-19 coulomb, find the number of electrons that will pass each second through the cross section of that conductor.

Answer 1

Q = n × e,

C = 3.2 m A = 3.2 × 1000 A,

Q = −1.6 × 10⁻¹⁹

3.2 × 1000 = n × −1.6 × 10⁻¹⁹

n = `(3.2 × 1000)/(1.6 × 10^-19)`

n = `(3.2 × 10^-3)/(1.6 × 10^-19)`

= `2/(10^-16)`

n = 2 × 10¹⁶