Question

How many electrons per second constitute a current of one micro ampere?

• A. one electron
• B. $10^{-6}$ electrons
• C. $10^{6}$ electrons
• D. $6.25 \times 10^{12}$ electrons

Answer 1

Answer: (D)

$q=n e$
$\frac{d q}{d t}=i=e\left(\frac{d n}{d t}\right)$
$\Rightarrow \left(\frac{d n}{d t}\right)=\frac{i}{e}=\frac{10^{-6} A }{1.6 \times 10^{-19} C }$
$ =6.25 \times 10^{12} \frac{\text { electrons }}{\text { second }}$