Find the current flowing through a copper wire of length 0.2m, area of cross-section `1 mm^(2)`, when connected to a battery of 4 V. Given that electron mobility `=4.5xx10^(-6) m^(2)V^(-1) s^(-1)` and charge on electron `=1.6xx10^(-19)C`. The number density of electron in copper is `8.5 xx10^(28) m^(-3)`.

Answer

`1.22 A`

Explanation

`I = n A e upsilon_(d) = n A e mu E = n= n A e mu (V)/(l)`
`= (8.5 xx 10^(28)) xx (10^(-3))^(2) xx (1.6 xx 10^(-19)) xx (4.5 xx 10^(-6)) xx (4)/(0.2)`
`= 1.22 A`