Wednesday, May 4, 2011

SPECIFIC RESISTANCE OR RESISTIVITY

The Specific Resistance or Resistivity of a material depends upon the nature and composition of the material.

From the relation ,


if  l = 1 m and A = 1 sq m
then R = 𝜌.

Hence, the specific resistance of a conductor may be defined as the resistance offered by unit m cube of the material of the conductor.


It can also be defined as the resistance of a conductor of 1 m length and 1 sq m cross-sectional area.


The unit of resistance is ohm-m or ohm per m³. 

If the unit of length is in cm,  then the unit of resistivity is ohm-cm or ohm-cm³.

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