Does the length of a wire affect the resistance? -- A* - page 2
Keywords: Physics length of wire resistance
By georgie1 on 31/12/2009
Level: GCSE Key Stage 4 (Years 10-11)
Page Number: 2 of 6 pages: 1 2 3 4 5 6
the lengths of wire using a metre ruler for accuracy, and will adjust the voltage of the circuit to as low as possible for all different lengths of wire. This is so that each length is tested in the same way as the others.
The apparatus that I will require for this experiment are as follows:
- 9 different lengths of constantan resistance wire. As the aim of my investigation is to see how the length of a wire affects the resistance of the circuit, I need a sufficient number of lengths of wire. This is so that I can easily depict anomalies and trends in my results, in order to draw an accurate conclusion.
- Power Supply. This is so that I can adjust the voltage, so that the potential difference of the circuit can be as low and as consistent as possible in all experiments.
- Ammeter. This is so that I can accurately measure the current (in amps) to see what affect a different length of wire has on the circuit.
- Voltmeter. This is so that I can accurately measure the potential difference (in volts) across the wire. As a result, when I change the length of the wire, I can keep all of the other variables as consistent as possible.
- Micrometer. This is so that I can check the diameter of the wire when I set up each experiment.
- Ruler. This is so that I can accurately measure the different lengths of wire.
- Leads. This is so that I can complete a full electrical circuit.
- Crocodile Clips. This is so that I can complete a full electrical circuit.
Preliminary Experiment
Wire SWG of Resistance Wire Diameter of Resistance Wire/mm Potential Difference /volts Current /amps Resistance /ohms Ω
A 24 0.6 0.08 4.57 0.02
B 28 0.37 0.17 4.33 0.04
C 32 0.29 0.32 3.96 0.08
D 36 0.19 0.55 3.35 0.16
E 40 0.11 1.03 2.14 0.48
Firstly, I did a preliminary experiment to understand exactly what I need to do to achieve the best results in my final investigation. I completed a similar experiment to see how the diameter of a wire affects the resistance. I wanted to see which wire would be the most reliable to use in my final investigation. I used 5 different diameters of the same length, temperature and material, and set the potential difference as low as possible to ensure all different wires were evenly tested. My results were as follows:
As you can see, wire C would be the best to use for my final investigation, because it provides the most appropriate current, which is not too low or too high. As a result, the wire will not overheat
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