Question

A wire is 1 m long zero. 0.2 mm in diameter and has a resistance of 100 ohm calculate the resistivity of its material

Answer 1

Resistance=resistivity×length/area
100= resistivity×1/π×10^-8
Resistivity=π×10^-6 ohm- metre
(area=πr^2=π×(0.1×10^-3)^2=π×10^-8m^2)