Question

How many electrons flow through a wire, when 1A current passes for a millisecond?

Answer 1

Current flowing through the wire $I=1$ A

Time of observation $t=1ms={10}^{-3}$ $s$

Charge of an electron $e=1.6\times {10}^{-19}$ $C$

Let $n$ be the number of electrons passing through the wire in time $t$.

Using $I=\frac{ne}{t}$

We get $n=\frac{It}{e}$

$\therefore$ $n=\frac{1\times {10}^{-3}}{1.6\times {10}^{-19}}=6.25\times {10}^{15}$ electrons