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What is meant by electrical resistivity of a material? Derive its S.I. unit. |
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Answer» Mathematically, resistivity of the conducting material is given by ρ = R x A/J If l = 1 m, A = 1 m2, then ρ = 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 Unit of ρ = Unit of R X Unit of area of cross -Section/Unit of length of Conductor = Ω x m2/m = Ωm |
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