# Resistivity & Conductivity of Conductor

## 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.