Answer to Question #251538 in Electric Circuits for SCHARLIE

Question

It has been estimated that there are about 1029 free electrons per cubic meter in

copper. Find the average drift velocity (in units of meters per hour) of electrons in a 1.0

mm diameter copper wire carrying a 3A current. Start your clearly shown work from

the definition of current, that is the amount of charge passing a cross-section per unit

time

Answer 1

After we relate the current to the cross-section area of the wire, we proceed to substitute the radius of the wire (0.5 mm = 0.0005 m), the current, the amount of free electrons per cubic meter (10²⁹ e^-/m³) and the charge that each electron has.

In conclusion, the average drift velocity (in units of meters per hour) of the electrons on such wire is 0.85836 m/h.