Question

The number of electrons passing through a heater wire in one minute, if it carries a current of $8A$, will be:

• A. $2\times {10}^{20}$
• B. $2\times {10}^{21}$
• C. $3\times {10}^{20}$
• D. $3\times {10}^{21}$

Answer 1

The correct option is D $3\times {10}^{21}$

The current is defined as rate of flow of charged particles, i.e., $I=\frac{Q}{t}$
Here, $I=8A$ and $t=1min=60s$
So, $8A=\frac{Q}{60s}$
This gives: $Q=480C$
Now, $Q=N\times e$, where $N$ is the number of electrons and $e$ is the electronic charge of value $1.6\times {10}^{-19}C$
$\therefore$ $N=\frac{Q}{e}=\frac{480}{1.6\times {10}^{-19}}=3.0\times {10}^{21}$