The Resistivity of Wires Essay Example for Free

The impedance of Wires EssayIntroduction Anthony Gullan Physics Coursework An Investigation to Find the Resistivity of Wires The Experiment The experiment that was used to experience the results was very simple. The voltage and current were measured whilst varying the length of fit out. The results for voltage and current were recorded along with the diameter of the wire. This allowed for a range of some other orders to be calculated, including cross-sectional area and resistivity. image00. png.The Equipment A baron supply A voltmeter and an Ammeter A jockey A micrometer A 1 meter prescript Wire Connecting cables What is Resistivity? The resistance of a conductor depends on three factors The literal The size of material (eg length) The temperature The equation for Resistance is R = ? l A In this equation the constant is called resistivity, ?. This is governed by the record of the material and is affected by temperature. Resistivity varies for different materials, but stays constant for a given(p) material. Below is a table illustrating a few materials resistivity.The equation for resistivity therefore is ? = RA L The units for resistivity are ? m (ohm-metres). Conductivity The opposite of resistivity is conductivity. This can be calculated by using this formula ? = 1/? The units are ? -1m-1. Predictions I return that the results that I work out allow for show these patterns As the length increases the resistance depart also increase there is more than wire resulting in more energy needed for the same results As the Cross-Sectional subject area increases the resistance will decrease the wire is wider resulting in more electrons being able to flow at any genius timeThis interpret is a straight diagonal line.This shows that Resistance and Length are directly proportional. In other words if one value increases by a certain amount then the other value will increase by a proportional amount. Although in this experiment there are a few anomal ies, caused either by technical problems or through human error, this graph shows a conceptive picture of the relationship between length and resistance of a wire.Resistance against Area and 1/Area Resistance (? ) o start with I will analyse Resistance against 1/Area. This graph shows that the cross-sectional area and the resistance of a wire are mutually proportional. At first the shape of the graph suggests that the two values are directly proportional.However, as the area is displayed as 1/area this makes it inversely proportional. This is because the equation for something that is inversely proportional is A ? 1/B, or in this case Resistance ? 1/Area read more. Conclusion From the data I have made three observations The length of the wire has a proportional effect on the resistance of the wire The cross-sectional are is inversely proportional to the resistance of the wire The length of the wire divided by the area of the wire and the resistance of a wire are proportional.Havi ng plotted a graph of these values the resistivity of the wire can be found out by calculating the gradient of the line. These observations can also be written as R ? L R ? 1/A ? = RA/L Evaluation I think that the results that were obtained were good. There were a few anomalies in the graph, however these did not seem to affect the calculations too much. The graphs that I could produce with the data showed how each aspect was related to the others. The experiment used to calculate the results could have been better.For example, more readings could have been taken i. e. every 5cm. However with the data I was given it was possible to show the relations between resistance, length, cross-sectional area and resistivity. read more. This student written piece of work is one of some(prenominal) that can be found in our GCSE Electricity and Magnetism section. Found what youre looking for? Start discipline 29% faster today 150,000+ documents available Just ? 6. 99 a month Get climb Acces s Now or Learn more Not the one?