what is the average number of electrons per second that flow past a fixed reference cross section that is perpendicular to the direction of flow

The complete question is;

In electronic circuits it is not unusual to encounter currents in the microampere range. Assume a 35 μA current, due to the flow of electrons. What is the average number of electrons per second that flow past a fixed reference cross section that is perpendicular to the direction of flow?

2.185 × 10^(14) electrons/seconds

Explanation:

We are given current as 35 μA = 35 × 10^(-6) Amperes

The value of the charge on one electron is; e = 1.602 × 10^(-19) coulombs

Now, from conversions;

One ampere = one coulomb/second =

Then, 35 × 10^(-6) Ampere's would give;

35 × 10^(-6) Coulombs/sec

Now,

1.602 × 10^(-19) coulombs = 1 electron

Thus;

35 × 10^(-6) Coulombs/sec gives;

(35 × 10^(-6))/(1.602 × 10^(-19)) = 2.185 × 10^(14) electrons /sec

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.