Question

In 5 minutes, a current of 5 amps is established in a wire. How many coulombs and how many electrons pass through each cross section of this wire?

Answer 1

The current is

$\displaystyle I = \frac{q}{t} \; \Longrightarrow \; q = It$

$q = 5 A \cdot5 \cdot 60 s = 1500\,C$

One electron has charge $1.6 \cdot 10^{-19} \, C$. Then

$\displaystyle N = \frac{q}{1.6 \cdot 10^{-19}} = \frac{1500}{1.6 \cdot 10^{-19}} = 937.5 \cdot 10^{19} = 9.375 \cdot 10^{21}$

Answer: $1500\; C, \, 9.375 \cdot 10^{21}$