College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 16

A length of metal wire has a radius of 5.00 × 10 3 m and a resistance of 0.100 . When the potential difference across the wire is 15.0 V, the electron drift speed is found to be 3.17 × 10 4 m/s. On the basis of these data, calculate the density of free electrons in the wire.