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The resistance of a material depends on:
(a) the temperature
(b) the dimensions of the specimen
(c) the material from which the specimen is made

The property of the material that affects its resistance is called the resistivity of the material and is given the symbol r.

The resistivity of a material is the resistance between two opposite faces of a 1 m3 specimen of the material.

Resistivity (r) = RA/L

The units for resistivity are Wm.

Example resistivities:Re Copper 1.69x10-8 Wm Resistivity Non metals 104 Wm
© Keith Gibbs 2009