Question

A current of 100 mA. flows through a wire. The charge on an electron is 1.6 × 10^-19 C. 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^-19 C

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 xx 10^-19) = 6.25 xx 10^17`.