Question

Give an example of drift velocity.

Answer 1

Hint: The rate of change of an object's location with regard to a frame of reference is its velocity, which is a function of time. A definition of an object's speed and direction of motion is referred to as velocity. Velocity is a physical vector quantity that requires both magnitude and direction to define.

Complete Step By Step Answer:
The average velocity achieved by charged particles, such as electrons, in a material owing to an electric field is known as drift velocity. Generally, an electron propagates at Fermi velocity at random in a conductor, resulting in an average velocity of zero. An electric field adds a little net flow in one direction to this random motion; this is the drift. The rate of drift is proportional to the current. It is proportional to the magnitude of an external electric field in a resistive substance. As a result, drift velocity may be used to explain Ohm's law. The simplest basic version of the rule is:
 $u=\mu E$
where u is drift velocity, $\mu$ is the electron mobility of the material, and E is the electric field.
Every conductible substance above absolute zero temperature, such as metals, will contain some free electrons travelling at random speeds. When a potential is placed around a conductor, electrons will tend to travel towards the positive potential, but they will hit with atoms and bounce back or lose part of their kinetic energy in the process. However, the electrons will accelerate back owing to the electric field, and these random collisions will continue to occur, but because the acceleration is always in the same direction due to the electric field, the electrons' net velocity will likewise be in the same direction.
Examples
Copper wires are the most frequent conductors of electricity. As a result, electrons are flowing at a rate of 23 m/s in this wire. This indicates that the electrons in a 60 Hz alternating current wander less than 0.2 $\mu$ m in half a cycle. To put it another way, electrons travelling through a switch's contact point never truly leave the switch.

Note:
While a potential difference is placed across a conductor, free electrons gain velocity in the direction opposite the electric field between collisions (and lose velocity when moving in the direction of the field), giving them a velocity component in addition to their random thermal velocity. As a result, the random motion of free electrons is overlaid atop a specified tiny drift velocity of electrons. There is a net flow of electrons in the opposite direction of the field due to this drift velocity.