Question

how many electrons crossing per second through any section of conductor constitute a current of one ampere?

Answer 1

current I = 1 A
time t = 1 s
charge q = I/t = 1 C

$$\begin{gathered} 1electronhascharge=1.6\times {10}^{-19}C \\ 1Cchargewillcontain=\frac{1}{1.6\times {10}^{-19}}electrons \\ =6.25\times {10}^{18}electrons \end{gathered}$$