Question

A current of 100mA. flows through a wire. The charge on an electron is 1.6 × 10^-19C. Find the number of electrons passing per second through the cross-section of the conductor.

Answer 1

 Given: I = 100mA = 100 × 10^-3 A = 0.1A, e = 1.6 × 10^-19C

Let n electrons are passing per second. charge on one electron = e

Total charge passed in one second = ne

Thus, i = ne or n = i/e = 0.1/(1.6 x 10^-19) = 6.25 x 10¹⁷.