How Does the Length of A Wire Affect Its Resistance?

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Thomas Cowles

Investigation: How Does the Length of A Wire Affect Its Resistance?

Outline Plan: -

In this investigation I am going to investigate how the length of a wire affects the resistance. I am going to connect some Nichrome wire to a power pack. In the circuit there will be an anmeter (which is in series) and a voltmeter (which is in parallel). I will take the readings from the voltmeter to record the voltages and I will take readings from the anmeter and record from it to record the currents.

        To investigate the effects the length of the Nichrome wire has on the resistance, I will make the wire shorter by 10cm each time (the full length of the wire will be 140cm) after each reading I do. To make the experiment fair I will use the same wire throughout the experiment so that the experiment won’t be bias. Also I will use a ruler so that I can cut the wire accurately without any pieces of wire cut off which are bigger or smaller than the cut wire before. I will find the resistance for each reading by dividing the voltage by the current: -

 R = V                                                  R = Resistance

         I                                                   I = Current

                                                             V = Voltage

This calculation will be able to help me draw a graph for the results.

Prediction: -

I predict that the shorter the wire, the lower the resistance because it is only a short distance for the current to travel so the current will run smoothly and quickly. The reason I think this would happen because in Nichrome wire there is no plastic or any other type of cover, but the wire is short there may be some air resistance but not as much if the wire is long. Also with a short wire, you may notice it becoming warm, which means that the current is going fast through the wire (but some heat resistance may slow it down a bit). Also since the wire is short, there are less particles in the wire to slow the current down meaning it would travel faster than if the wire was long and that there would be less resistance as well.

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Detailed Plan: -

To make the experiment a fair test, I will use the same voltage throughout the experiment on every length of wire.

The equipment I will use for the experiment is: -

  • Nichrome wire.
  • An Anmeter (to measure current).
  • A Voltmeter (to measure voltage).
  • Power Pack.
  • Crocodile Clips (to hold piece of wire).
  • Other wires (to make the circuit for the experiment).
  • 2 metre rulers (to measure the Nichrome wire).

The Nichrome wire I will use will be cut from 140cm to 50cm. The Nichrome wire will be taped to 2 metre ...

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