Arrive at an expression for drift velocity.

Explanation

If V is the potential difference applied across the ends of a conductor of length I, the magnitude of electric field set up is `E= (V)/(l)`

The charge on electrons is - e free electron in the conductor experience force `barF=-e.barE`
If m is the mass of an electron the acceleration of each electron is `vec a=(-e.vecE)/(m)` at anyinstant of time the velocity acquired by electron having velocity `vecu_(1)` will be
`therefore` the average velocity of all the free electrons in the conductor under the effect of external electric field is the drift velocity `vec u_(d)` of the free electrons
by the free electron to just leave the metal surface is known as work function.
(ii) Electron volt: One electron volt is the energy acquired by an electron when it is accelerated through a potential difference of one volt.
`therefore vec v_(d)=(-e vecE)/(m)tau`
`therefore |vec v_(d)|=(eEtauy)/(m)`