Question

What is meant by electricity resistivity of a material? Derive its SI unit Describe an experiment to study the factor on which the resistance of a conducting wire depends

Answer 1

p = R x A/J

If l = 1 m, A = 1 m2, then p = R

Hence, the resistivity of the material is defined as the resistance offered by a metallic wire having a unit length and a unit area of cross-section. Since unit length and unit area of cross-section forms a cube, the specific resistance or resistivity can also be defined as the resistance offered by a cube of a material of side 1 m when current flows perpendicularly through the opposite faces. In SI system, its units is ohm m.