Question:
A current of 1A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be
roughly
(a) 1020
(b) 1016
(c) 1018
(d) 1023
Solution:
(a).
Explanation : $I=\frac{Q}{t}=\frac{n e}{t}$
$\therefore$ $n=\frac{\mathrm{It}}{e}=\frac{1 \times 16}{1.6 \times 10^{-19}}=10^{20}$