The number density of free electrons in a copper conductor is `8.5xx10^(28)m^(-3)` . How long does an electron take to drift from one end of a wire of 3.0 m long to its other end? The area of cross-section of the wire is `2.0 xx10^(-6)m^(2)` and it is carrying a current of 3.0 A.

Explanation

I=3A.n=`8.5xx10^(28)m^(-3), " " e=1.6xx10^(-19)C," "A=2xx10^(-6)m^(_2).l=3m`
`v_(d)=(I)/("ne"A)=(3)/(8.5xx10^(28)xx1.610^(-19)xx2xx10^(-6))=1.1xx10^(-4)m"/"s`
`t=(l)/(v_(d))=(3)/(1.1xx10^(-4))=2.27xx10^(-4)m"/"s`