Calculate the resistivity of the material of a wire `1.0 m` long, `0.4 mm` in diameter and having a resistance of `2.0 Omega`.

Answer

`25 xx 10^-8 ohm m`

Explanation

As `R = (rho l)/(A) = (rho l)/(pi r^2), rho = (pi R r^2)/(l)=(3.14 xx (2.0 Omega) xx (0.2 xx 10^-3 m)^2)/(1.0 m) =25 xx 10^-8 Omega m`.