Copper has 8.5 x 1078 free electrons per cubic meter. A 71.0-cm length of 12-gauge copper wire that is 2.05 mm in diameter carries 4.85 A of current.
(a) How much time does it take for an electron to travel the length of the wire?

(b) Repeat part (a) for 6-gauge copper wire (diameter 4.12 mm) of the same length that carries the same current.

(c) Generally speaking, how does changing the diameter of a wire that carries a given amount of current affect the drift velocity of the electrons in the wire?