SSE JE Electrical Engineering 10 Dec 2020 Papers

We know that $\mathit{e}=1.6\times {10}^{-19}$ C, i.e charge on the electron.
The total charge required is 1 Coulomb, q = 1C
Therefore we also know that q = n × e, (n = number of electrons on the charge)
Hence, $\mathit{n}=\frac{\mathit{q}}{\mathit{e}}$ ....(1)
Substituting all the values in the equation (1)
$\mathit{n}=\frac{1}{1.6}\times {10}^{-19}\mathit{}$ $=625\times {10}^{16}$
So, if 1A current flows through the conductor then $625\times {10}^{16}$ electrons flow per second across the cross-section of the conductor.