Question

What is the difference between ‘velocity’ and ‘drift velocity’ of electrons in a current-carrying conductor.

Answer 1

1. Velocity:

The velocity of an electron in a conductor refers to the actual speed and direction of its motion. It is the instantaneous velocity of an electron as it moves randomly in all directions due to thermal energy. This velocity is very high (on the order of \( 10^6 \, \text{m/s} \)) and does not contribute to the net current.

2. Drift Velocity:

The drift velocity is the average velocity of conduction electrons in a conductor when an electric field is applied. It is the net velocity that contributes to the flow of current in the conductor. The drift velocity is much smaller than the actual velocity of electrons and is typically on the order of \( 10^{-3} \, \text{m/s} \).

3. Difference:

The key difference is that while the velocity of an electron is its instantaneous motion in random directions due to thermal energy, the drift velocity is the net average velocity in the direction of the applied electric field, which leads to the flow of current.