An investigation into the factors affecting the resistance of a wire.

Prediction:

Resistance affects the flow of current within a wire by opposing the flow of electrons.  These free-flowing electrons relate directly to the current and when there is resistance heat is produced because of the opposing electrons. A law was devised and was named after the German physicist, George Ohm who discovered the relationship in 1827.  The law states that:

The electric current flowing through a metallic conductor is directly proportional to the potential difference between its ends, as long as the temperature stays the same.  As quoted on Encarta (Multimedia CD)

The unit of resistance is the Ohm, the amount of resistance that limits the passage of one ampere when one volt is applied to it.

To work out the resistance of a material is to use the formula:

R=V/I                     R-Resistance

V-Voltage

        I-Current

From this equation we can derive that the greater the voltage the greater the resistance but more current there is the smaller the resistance.

From the information gathered I am now able to predict the likely outcome of resistance of the wire when both the wire is decreased in size and the cross-sectional area is increased.  As the size of the wire is decreased so is the resistance as less current is passing through the wire, therefore the resistance will be lower because of less opposing electrons in the wire.  Also, when the cross-sectional area of the wire is increased the resistivity of the wire will also decrease therefore the resistance is low.