Calculate the drift speed of the electrons when `1A` of current exists in a copper wire of cross section `2mm^2` The number of free electrons in `1cm^3` of copper is `8.5xx10^22`

Explanation

`n =` free electron density,
`=8.5xx10^22"per" cm^3`
`=(8.5xx10^2)(10^6)"per" m^3`
`=8.5xx10^28 "per" m^3`
From `i = "ne" Av_d,` we get
`v_d=i/("ne" A)`
substituting the values in `SI` units we have
`v_d=1/((8.5xx10^28)(1.6x1^-19)(2xx10^-6))`
`=3.6x10^-5m//s`