Question

When 5 V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is 2.5 x 10^-4 m/s. If the electron density in the wire is 8 x 10²⁸ m^-3, calculate the resistivity of the material of the wire.

Answer 1

The drift speed is

`v_d=I/(`

Now, we know that the current is given from Ohm’s law as

`I=V/R`

`:.v_d = V/`

`:.V/(`

`=>V/(`

Now, resistivity is given as `rho=(RA)/l`

`:.V/(`

`:.rho=5/(8xx10^28xx1.6xx10^(-19)xx2.5xx10^(-4)xx0.1)`

∴ ρ = 1.56 x 10^-5 Ωm