What is the symbol of resistivity

Specific resistance ρ (rho)

Each material has its own resistance, which depends on the atomic density and the number of free electrons. The resistance is therefore also called specific resistance. This means the resistance that relates to a specific material.
The shorter the cable length and the larger the cable cross-section of the material, the lower the ohmic / electrical resistance. The dependence on the line length is explained by the fact that the electron movement is more strongly inhibited over a longer distance than over a shorter distance. Changing the cable length and cross-section only changes the ohmic resistance.
The specific resistance is a material constant and is therefore a firmly defined value.

Definition: The resistance of a conductor 1 m long and 1 mm² cross-section at 20 ° C is called the specific resistance.
The reciprocal of the specific resistance is called electrical conductivity.

Formula symbol

The symbol of the specific resistance is ρ (rho) from the Greek alphabet.

Unit of measurement

The specific resistance is given on the basis of 1 m length, 1 mm² cross section at a temperature of 20 ° C.

Formula for calculation


Examples of specific resistance (at 20 ° C)

silver ρ = 0.015
copperρ = 0.01786
aluminumρ = 0.0278

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