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GCSE Physics Coursework - Resistance of a Wire CourseworkResistance of a WireTaskTo investigate how the rampart of a wire is affected by the length of the wire.TheoryWhat is resistance?Electricity is conducted through a conductor, in this case wire, by message of unloosen electrons. The number of free electrons depends on the material and more free electrons means a better conductor, i.e. it has less resistance. For example, aureate has more free electrons than iron and, as a result, it is a better conductor. The free electrons are given energy and as a result terminate and collide with neighbouring free electrons. This happens across the length of the wire and thus electricity is conducted. Resistance is the result of energy loss as heat. It involves collisions between the free electrons and the rigid particles of the metal, other free electrons and impurities. These collisions convert some of the energy that the free electrons are carrying into heat.How is it measured?The r esistance of a length of wire is calculated by quantity the current present in the circuit (in series) and the voltage across the wire (in parallel). These measurements are then applied to this formulaV = I R where V = Voltage, I = Current and R = ResistanceThis can be rearranged toR = VIOhms LawIt is also relevant to know of Ohms Law, which states that the current through a metallic conductor (e.g. wire) at a constant temperature is proportional to the potential difference (voltage). Therefore V I is constant. This means that the resistance of a metallic conductor is constant providing that the temperature also remains constant. Furthermore, the resistance of a metal increases as its temperature increases. This is because at higher temperatures, the particles of the conductor are moving around more quickly, thus increasing the likelihood of collisions with the free electrons.VariablesInputLength of wire. * Material of wire. Width of wire. Starting temperature of wire. Output and thus the resistance of the wire. Voltage across wire. Current in circuit. Temperature of wire. The variable marked with a * will be varied, the other input variables will be kept constant. The create variable marked with a will be measured.PredictionsThe longer the wire, the higher the resistance. This is because the longer the wire, the more times the free electrons will collide with other free electrons, the particles making up the metal, and any impurities in the metal.