Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) quantifies how strongly a given material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electric charge. Resistivity is commonly represented by the Greek letter Ï (rho). The SI unit of electrical resistivity is the ohmâ‹…metre (Ω⋅m)123 although other units like ohmâ‹…centimetre (Ω⋅cm) are also in use. As an example, if a 1m×1m×1m solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is 1Ω, then the resistivity of the material is 1Ω⋅m.
Electrical conductivity or specific conductance is the reciprocal of electrical resistivity, and measures a material's ability to conduct an electric current. It is commonly represented by the Greek letter σ (sigma), but κ (kappa) (especially in electrical engineering) or γ (gamma) are also occasionally used. Its SI unit is siemens per metre (S⋅m−1) and CGSE unit is reciprocal second (s−1).
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