Question

If a current of $0.5$ ampere flows through a metallic wire for $2$ hours, then how many electrons would flow through the wire?

• A. $2.25 \times 10^{-22}$ electrons
• B. $3.7 \times 10^{-11}$ electrons
• C. $7.5 \times 10^{24}$ electrons
• D. $2.25 \times 10^{22}$ electrons

Answer 1

Answer: (D)

$ Q = I \times t = 0.5 \times 2 \times 60 \times 60 $
$= 3600 \,C$
Charge on $1$ electron is $1.602 \times 10^{-19} C$
$3600\,C $ is charge on $\frac{1}{1.602 \times 10^{-19}} \times 3600$
$ = \frac{3600}{1.602} \times 10^{19}$
$ = 2.25 \times 10^{22}$ electrons