Question

Consider a wire of length 4m and cross-sectional areal `1 mm^(2)` carrying of 2A. If each cubic metre of the material contains `10^(29)`free electrons, find the average time taken by an electron to cross the length of the wire.

Answer 1

`impliesv_(d)=(i)/(nAe)=(2)/(10^(29)xx10^(-6)xx1.6xx10^(-19))ms^(-1)`
`=12.5xx10^(-4)ms^(-1)`
Average time taken by an electron to cross the length of wire
`t=(l)/(v_(d))=(4)/(1.25xx10^(-4))s=3.2xx10^(4)s`