Resistivity & Conductivity of Conductor

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Resistivity of Conductor-

 

Before you go through this article, make sure that you have gone through the previous article on Resistance of Conductor.

 

We know-

The resistance of a conductor of length L and area of cross-section A is given by-

 

 

If L = 1 unit and A = 1 unit, then R = ρ

 

Thus, resistivity of material of a conductor may be defined as-

 

The resistivity of a material may be defined as the resistance of that material having unit length and unit area of cross-section.

OR

It is the resistance offered by the unit cube of that material.

 

It may be noted that-

  • The resistivity is a property of material of the conductor.
  • It is also called as specific resistance.

 

SI Unit of Resistivity-

 

The SI unit of resistivity is ohm meter (Ω m).

 

The SI unit of resistivity may be derived as-

 

 

Factors Affecting The Resistivity-

 

The resistivity of material of a conductor depends upon the following factors-

 

1. Nature of Material-

 

  • The resistivity of a conductor depends upon the nature of its material.

 

2. Temperature-

 

  • The resistivity of a conductor also depends on its temperature.
  • The resistivity of a conductor increases with the increase in its temperature.

 

Very Important Note

The resistivity of a conductor is independent of the dimensions of the conductor.

In other words,

The resistivity of a conductor does not depend upon its length and area of cross-section.

At a constant temperature, it depends only on the nature of material of the conductor.

 

Conductivity of Conductor-

 

The reciprocal of the resistivity of a material is called its conductivity.

 

  • More is the resistivity of a conductor, lesser is its conductivity and vice-versa.
  • So, conductivity of a conductor is defined as reciprocal of resistivity of the conductor.
  • It is denoted by σ.

 

Mathematically,

 

OR

 

The SI unit of conductivity is ohm-1 m-1.

 

Read the next article on-

Temperature Dependence of Resistance

 

Get more notes & other study material of the Chapter Current Electricity.


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