Resistance in Wires

Resistance in Wires

What is the purpose of a resistance wire? A resistance wire converts

electrical energy into heat energy, and this is also its soul purpose.

An example of a resistance wire is in a light bulb. The electrical

energy is converted into heat, which then heats up the filament in the

light bulb. This in turn creates the light needed.

Resistance is a force, which opposes the flow of an electric current

around a circuit so that energy is required to push the charged

particles around the circuit. The circuit itself can resist the flow

of particles if the wires are either very thin or very long. e.g. The

filament across an electric light bulb

Predictions: The diameter of the wire will have an affect on the

resistance as Ohms law states that ‘if the cross section of the wire

is uniform then the resistance is proportional to the length and

inversely proportional to the area of the cross section’. This is

because the electrons have to squeeze together more to pass through a

thin wire than they do to pass through a thick wire. [IMAGE]

Length of the wire - The length of the wire will make a difference.

This is because when you have a long wire, the electrons have to

squeeze together for longer to be able to pass through the wire than

they do in order to be able to pass through a short wire. I predict

that the longer the wire, the greater the resistance. I also predict

that if I had a 20 cm wire and a 40 cm wire, the 40 cm wire would have

a resistance twice that of the 20 cm wire.

Material of the wire - The type of material will make a difference

because the electrons have to pass through the material. These

electrons find it easier to pass through some materials than others.

In this experiment I am going to use manganin, constanton and nichrome

wire. I predict that the nichrome wire will have a higher resistance

than the other wires.