Resistance is defined as the opposition to the flow of electrical current through a conductor. The resistance of an electric circuit can be measured numerically. Conductivity and resistivity are inversely proportional. The more conductive, the less resistance it will have.
Resistance = Potential difference/ Current
Factors on which conductor depends
The resistance of the conductor depends on the following factors:
- The temperature of the conductor
- The cross-sectional area of the conductor
- Length of the conductor
- Nature of the material of the conductor
Electrical resistance is directly proportional to the length (L) of the conductor and inversely proportional to the cross-sectional area (A). It is given by the following relation.
where ρ is the resistivity of the material (measured in Ωm, ohm meter)
Resistivity is a qualitative measurement of a material’s ability to resist flowing electric current. Obviously, insulators will have a higher value of resistivity than of conductors.