A copper wire has a radius of 0.8mm and carries a current of 0.45A. If 8.5x10 28 m-3 electrons contribute to the electrical conductivity calculate their drift velocity? How long does it take a given electron to travel 1m? What is the kinetic energy of the electrons corresponding to this velocity? How does this energy compare with a typical spacing between energy bands of 1eV, could this energy cause an electron to be excited between the bands?