What do you understand by the “resistivity” of a substance? b) A wire is 1.0m long, 0.2 mm in a diameter and the has a resistance of 10Ω. Calculate the resistivity of its material?

1. Resistivity is defined as the characteristic property of a substance which is dependent on the nature of the substance and the temperature of the substance used in the It is numerically equal to the resistance between the opposite faces of a cube with sides 1m.

1. Given, l = 1m

r = d/2 = 0.2/2 = 0.1mm = 0.0001m

R = 10ohm We know that,

R = ρl/A ρ = RA/l

= 31.4×10-8ohm