Drift velocity: The figure shows a steady electric current passing through a wire with a narrow region. What happens to the drift velocity of the moving charges as they go from region A to region B and then to region C?

Question

Quizplus · Accepted Answer

In region A, the cross-sectional area is larger, which means the same amount of charge is distributed over a larger area, resulting in a lower current density and hence lower drift velocity. In region B, the cross-sectional area is smaller, which means the same amount of charge is distributed over a smaller area, resulting in a higher current density and hence higher drift velocity. In region C, the cross-sectional area returns to the larger size in region A, resulting in a decrease in current density and hence lower drift velocity. Therefore, drift velocity increases from A to B and then decreases from B to C.

Drift Velocity: the Figure Shows a Steady Electric Current Passing