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Testing the theory that increasing the length of a piece of wire increases the resistance.
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Aim: My aim in this experiment is to investigate how the electrical resistance of a wire is affected in relationship to the length of that wire Factors affecting resistance these include: · Diameter or thickness of wire · Temperature at which wire is kept · The material from which the wire is made. · The length of the wire In my experiment I will only be investigating one factor which is the length of the wire. The wire I am using is made out of nichrome. Background information: Resistance controls the amount of current flowing through a particular component in a circuit. Resistance slows down the current. Current is defined as the rate of flow of electrons through a circuit current is measured in amps. A circuit can only possess a current if there is a voltage across a component. The voltage is the force that is exerted onto the electrons to allow them to flow through the circuit. In 1826 a German physicist called George Ohm discovered a new rule which said that for a given conductor at a fixed temperature voltage is directly proportional to current. This relationship is better known as Ohms law. Ohms law also shows that resistance can be calculated using the following formula: Resistance = Potential difference / Current Resistance occurs when a large amount of electrons are pushed through a conductor and so they collide with positive ions in the lattice. When they collide they lose energy which slows them down. This energy is picked up by the ions this results in a reduced current and a increase in temperature. Hypothesis: I think that as the length of the wire increases so to will the resistance of it. I also believe that the rate at which the resistance of the wire increases will be directly proportional to the length. The graph to show this should therefore look something like this: Resistance Length I think this because (as I have briefly explained in the introduction) with electricity, the property that transforms electrical energy into heat energy, in opposing electrical current, is resistance. A property of the atoms of all conductors is that they have free electrons in the outer shell of their structure. As a result of the structure of all conductive atoms, the outer electrons are able to move about freely even in a solid. When there is a potential difference across a conductive material all of the free electrons arrange themselves in lines moving in the same direction. This forms an electrical current. Resistance is encountered when the charged particles that make up the current collide with other fixed particles in the material. As the resistance of a material increases so to must the force required to drive the same amount of current.
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