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Resistance in a piece of wire Aim: My aim is to see if increasing the length of the wire effects the resistance when the potential difference is kept constant 2.00 volts. Objective The objective of this experiment is to find out the resistance in a piece of wire and to see if it is true that when 2.00 of voltage is put though a 1 meter wire has more resistance than putting 2.00 voltage through a 10cm wire. Key factors: I have decided to use 100 cm of wire. Because the wire does still pass a good amount of electricity through it without burning or melting. The four factors, which you have to take into account, are: Varying length- the longer a piece of wire the greater the resistance. The way I am going to measure this is by using an Ammeter and a Voltmeter. Varying cross-sectional area - the wider the wire the less resistance you will have because the electrons have more space to move. Temperature - If you have the power on for too long the wire heats up and may make the results invalid. Turning off the power pack will control this when taking results. Conductivity - For the purposes of this experiment, the wire must be a good conductor. The experiment will be carried out in a science room under the following conditions: Constant temperature - the experiment will be carried out at room temperature. Single material- The experiment will only use one material e.g. Nichrome SWG32 Constant thickness- The wire will have the same thickness though out the experiment. This will enable the effect of changing of the wire length to be tested and the results will still be valid. Definitions This experiment will use Ohm’s law as its basis. Ohms law- George Simon Ohm (1789-1854) showed that all conductors, even the test metals, resist the flow of electricity to an extent. The unit of electrical resistance is called Ohm in his honour. Ohm’s law says that the current flow through a conductor, in Amps, is proportional to the potential difference across it, in volts = amps x Ohms. Voltage- Electromotive force or potential difference usually expressed in volts. Current- a flow of electric charges flowing past a specified circuit point per unit time.
Approximate Word count = 1509
Approximate Pages = 6
(250 words per page double spaced)
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