Drift Velocity of Electrons
Most recent answer: 05/24/2018
- Shambhavi Singh (age 16)
Varanasi, UP, India
The average drift velocity only becomes independent of time after a brief period of change right after the electric field is switched on. The electrons at first accelerate, on average, giving an increasing drift velocity. The scattering of electrons by defects and sound waves causes an average force that opposes the drift motion. After a very short time the drift becaomes large enough so that that force balances the force from the applied field, and the drift velocity becomes independent of time.
If the voltage changes over time, for example because the material is connected to an ac power source, then the drift velocity will change too. That happens all the time in ordinary electrical wires.
Mike W.
(published on 05/24/2018)