The resistance of a wire Essay Example for Free

The enemy of a conducting fit EssayThe issuings all proved to be so close together that it proves its not worth doing it for either measurement. Results 1 This table shows the imports we took, with the length in centimetres running along the side, and the voltage along the top. The corresponding determine in the table is the current, measured in Amps. I will now plot these results onto nine fork graphs and a last graph showing Length plotted against resistance. These results were taken in conjunction with tenner Cubbage. Each of us took part the taking of results. Final Results Length of Wire (cm) Resistance (? )Analysing and drawing conclusions all these results and graphs show things about the relationship between Resistance and length of wire. The final examination graph shows an almost undefiled forthwith line of results through the origin. This proves that resistance is directly proportional to the length of wire. If you look carefully on the graph you can fit a slight change in pattern after the result for 50cm. This is due to the fact that results were taken over dickens lessons, the first 4 one day and the final 5 the next.The slight split could be due to a assorted set of equipment, slightly several(predicate) components (different power supply etc. ) or even something as little as room temperature. If the results were taken over a adept period of time I have no doubt there would be an absolutely straight line. The results also prove that doubling the length of wire, effectively doubles the resistance. For typeface if you look at the results for 20cm of wire (0. 8 and then the results for 40cm of wire (1. 6 you will trip up that the resistance for 40cm of wire is exactly double that of 20cm.All this evidence supports the prediction I made at the start, that the length of a piece of wire does indeed affect its resistance, and that there is a direct and proportional touch on between the two. Evaluation I imagine my results were fairly reliable and this was mostly thanks to the system of acquiring an average resistance from each length of wire, using a graph to average out the results. As I said before, there is a slight change in pattern after the result for 50cm. This is due to the fact that results were taken over two lessons, the first 4 one day and the final 5 the next.The slight split could be due to a different set of equipment, slightly different components (different power supply etc. ) or even something as little as room temperature. The equipment apply over the two lessons may have differed slightly, e. g. the meters used to measure current and p. d. If the results were all taken in one go I have no doubt there would be an absolutely straight line. If you draw a line from the point of origin up to the fourth point you can see it is perfect, likewise if you draw a line from the fifth point on the graph to the ninth.I think this was a very suitable procedure and was certainly the most accura te way of performing this experiment. The precisely way I would improve it would be by taking all the results over a single period of time. This would avoid the split in the middle of the results. You could do another couple of different lengths however it wouldnt make much difference to the results. Just using the range that I have you can see all that you need to see to draw conclusions. I would like to try an identical experiment with a wire made of different material, just to see how different the results would be and then compare the two experiments.The real test for how accurate my results were is to calculate the Resistivity of my results and to compare it with the Resistivity that the wire should be. Resistivity is a property of a metal (whereas resistance is a property of a component). Resistivity does not attend on the dimensions of a component, only on the material from which it is made. We have done previous experiments to show that the resistance (R) of a conductor i s directly proportional to its length (l) and is inversely proportional to its area (A).The diameter for the wire used was around 0. 8mm. To put this into a formula, where p is the Resistivity R = pl A So P (Resistivity) = AR l If we take the results for 80cm of wire we can work out the Resistivity of Constantan (the mix wire we are using). In an A-level textbook I looked up the Resistivity of Constantan and discovered it should be 4. 9 x 10 -8 ? /m These two figures are fairly close and this indicates how accurate my experiments were.