28)
If charges moved without collisions through the conductor, their
kinetic energy would also change so that the total energy is unchanged Conservation of total energy would then imply that,
DK =  –DUpot
(3 29)
that is,
DK = I VDt > 0
(3 30)
Thus, in case charges were moving freely through the conductor under
the action of electric field, their kinetic energy would increase as they
move