What factors affect the resistance of wire?

Authors Avatar

Katherine Short 10F1

What factors affect the resistance of wire?

Plan

The aim of this investigation is to find out what factors affect the resistance of wire and how.  Once, through my research, I have found out those factors I am going to select one to do my experiment on to prove that it is correct.

There must be a potential difference (voltage) across to make a current flow through a conductor.

This is the formula to work out the resistance of a wire:

Resistance (Ω) = Potential Difference (V)

                      Current through conductor (A)

R = V                Where R = Resistance, V = Pd (Voltage), I = Current

       I

V = IR                and I = V        

                          R

Factors affecting resistance

  • Length – Doubling the length of a wire doubles its resistance.
  • Cross sectional area – Halving the width of the wire doubles its resistance.  So a thin wire has more resistance then a thick one.
  • Material – Copper-connecting wire is a good conductor and a current passes through it easily.  A nichrome wire has more resistance then a copper wire of the same size.
  • Temperature – For metal conductors, resistance increases with temperature.  For semi-conductors, its decreases with temperature.

I am going to investigate how length affects the resistance of a wire.  I will change the length of the wire through a range of readings.
Join now!

My prediction is that as the wire gets shorter the resistance become smaller e.g. if it is half the length it should have half the resistance. I think this because the wire is full of atoms and the electrons have to try and get through it. So if the wire is short there is less atoms so the electrons will travel easier.  If the wire is long there are a lot more atoms the electrons have to travel through more atoms making it harder to travel through the wire.

Resistance is caused by the internal structure of the metal getting ...

This is a preview of the whole essay