# All Factors That Affect The Resistance Of A Conductor

There is no ‘perfect’ electrical conductor; every conductor that makes up the wires has some level of resistance no matter what kind of material it is made from.

**There are four main factors affecting the resistance in a conductor: The cross-sectional area of the wire (A), length of the conductor (ℓ), temperature (T), and resistivity of the material (ρ)**

## Factors Affecting Resistance of a Conductor

Factors affecting the resistance of a conductor are:

### 1.Cross-sectional area of the wire (A)

More water will flow through a wider pipe than that through a narrow pipe. Similarly, the larger the diameter of the wire, the greater the cross-sectional area, the less the resistance in the wire, and the more the flow of current.

### 2.Length (ℓ)

The longer the wire, the more resistance and the more time is taken for the current to flow.

### 3.Resistivity (ρ)

It is a measure of the opposition to flowing current through a material of the wire, or how difficult it is for current to flow through a material. The different materials have different resistivity, i.e. more or less resistance in the materials.

### 4.Temperature (T)

The resistivity of a material is dependent upon the temperature surrounding the material. Resistivity increases with an increase in temperature for most materials. The table below lists the resistivity of some materials at 20 °C.

Factors affecting resistance can be mathematically expressed with the following formula:

A is the cross-sectional area, ℓ the length, T is the temperature, and ρ the resistivity (conducting ability of a material for a wire.)

**Example**

There is a copper wire 50 m in length with a cross-sectional area of 0.13 cm². What is the resistance of the wire?

The resistance of this copper wire is 0.0646 Ω. Although there is resistance in the copper wire, it is very small. A 50-m-long wire only has 0.0646 Ω resistance; thus we can say that copper is a good conducting material. Copper and aluminum are commonly used conducting materials with reasonable prices and better conductivity.