A copper wire of `10^(-6)m^(2)` are of cross section, carries a current of 2A. If the number of electrons per cubic meter is `8xx10^(28)`, calculate the current density and average drift velocity.

Explanation

Cross-sections area of copper wire, `A=10^(-6)m^(2)`
`I=2A`
Number of electron, `n=8xx10^(28)`
Current density, `J=(I)/(A)=(2)/(10^(-6))`
`J=2xx10^(-6)Am^(-2)`
Average drift velocity, `V_(d)=(I)/(n eA)`
e is the charge of electron `=1.6xx10^(-9)C`
`V_(d)=(2)/(8xx10^(28)xx1.6xx10^(-19)xx10^(-6))=(1)/(64xx10^(3))`
`V_(d)=0.15625xx10^(-3)`
`V_(d)=15.6xx10^(-5)ms^(-1)`