## Resistivity of Various Materials

The resistivity of a material, (units Ohm metre, symbol) is it's ability to resist the passage of an electric current. Resistance is measured in Ohms (symbol) and resistance defined as the resistance between the faces of a cubic metre block of material, or more practically, calculated from the equationwhereis the length of the material along which the current passes andis the constant cross sectional area. Some resistivities for various materials are given below.

All values at 20 °C.

Material

Resistivity (Ohm metre)

Aluminium

Carbon

Copper

Germanium

.46

Glass

to

Gold

Hard Rubber

Iron

Nichrome

Platinum

Quartz (Fused)

Silicon

Silver

Sulphur

Tungsten

The conductivity of a material (unitssymbol)is it's ability to conduct electricity and is defined asThe conductivity of Germanium is