Question

If a metal wire carries a current of 130 mA,
how long does it take for 3.50×10
20
electrons
to pass a given cross-sectional area anywhere
along the wire? The magnitude of the charge
on an electron is 1.6 × 10
−19
C.
Answer in units of s.

Answer 1

That many electrons have total charge
Q = 3.5*10^20*1.6*10^-19 = 56 Coulombs

Require that I*t = 56 C
where I is the current in Amps (Coulombs per second).
I = 0.130 C/s

Solve for t.

Answer 2

430.7692308