Factors Affecting the Resistance of a Wire

Factors Affecting the Resistance of a Wire

The aim of this experiment is to investigate one factor that affect

the resistance of a wire. I will do this by performing an experiment.

First I will need to identify the factors that effect resistance.

There are a few factors that affect the resistance, it is determined

by the properties an object has. This is know as resistivity.

The factors I can investigate are :

Ÿ Temperature

Ÿ Length

Ÿ Cross-sectional area/width

Ÿ Material (resistivity)

The factor I shall investigate is the length of a wire.

Background Knowledge

Resistance is when electrons travelling through the wire are impeded

by the atoms within the wire. Since the electrons are charge carriers

when they collide with the atoms in the wire less pass through. There

fore less current passes through with the same voltage. Simply it is

how hard it is for the electrons to pass through the wire.

Temperature:

When the metal wire is heated , more energy s given to the atoms,

therefore they vibrate more. From this there is a greater chance of

collisions with the electrons and they are impeded more, therefore

less charge is passed by the electrons and the resulting current is

reduced.

This means while conducting the experiment the temperature of the wire

must be kept constant to maintain a safe and fair test.

Cross-sectional area/ width:

If the cross sectional area is increased there is more space for the

electrons to move freely making less collisions so more current will

pass through making the resistance decreased. I have done a diagram

below.

[IMAGE] [IMAGE]

Small wire Large wire

Length:

If the length of a wire is increased there are more atoms for the

electrons to collide with. There for less gets through meaning the

current is less so the resistance is increased. I have done a diagram

below to help me understand this.

Material/resistivity :

Different wires composed of different metals will have differing