Question

Explain why there is no current in a metal although there are free electrons in motion.

Answer 1

1. There is no current in a metal under normal conditions (without an applied electric field) even though free electrons are present, because their motion is completely random.
2. In a metal, free electrons move in all directions with equal probability. Since their motion is random and scattered, the net flow of charge in any one direction is zero, resulting in no electric current.
3. However, when an external electric field is applied, these electrons begin to drift in a particular direction, creating a net flow of charge, i.e., electric current.
4. Thus, current only flows when there is an external driving force that aligns the motion of free electrons.