To carry out the investigation, I am going to use various thicknesses of wires. These will be secured to a ruler

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Physics coursework

I am going to do an investigation into the resistance of a wire when various currents are passed through it. There are many things that could effect the resistance of the wire we are going to use, these include;

Material the wire is made from

Temperature of the wire at the time the reading is made

The length of the wire

The diameter of the wire

The material of the wire can affect the resistance because various materials conduct electricity better than others, if the wire were made out of an insulating material such as plastic there would be a very high resistance through the wire. Whereas if the wire were made out of a metal, the electricity would pass through the wire with great ease.

Temperature effects the resistance of a wire, this is because if the wire hot when the current is passed through it, the particles will have more energy in them. This means that they will be moving more, and at a greater rate than if they were cold. This means that they will pass the charge on to the next particle easier.

Electricity has to move from atom to atom along the wire, which means that if we double the length of the wire, we would need to double the current. This is because there are more particles for the current to pass through in a longer length of wire than in a shorter one. This means that as the length of the wire is increased, the resistance will also increase. This idea is also true with the diameter of the wire. If the wire is thicker, there are more possible ways in which the electricity can flow. There are more atoms spread out, which means the flow of electricity has more routes in which to travel through. If the thickness of the wire is doubled, the resistance would half, as the energy is spread out more than if there were a few possible ways in which it could flow, where there would be the same amount of energy but in a smaller space. I am going to change the diameter of the wire. This means that I am going to need to keep all the other variables constant to ensure that this is a fair test. By measuring the resistance at various lengths, I am also investigating the length of the wire. Therefore the only other variable that I need to keep constant is the temperature, by doing the investigation at room temperature I am ensuring that this is kept fair.
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Method

To carry out the investigation, I am going to use various thicknesses of wires. These will be secured to a ruler making it able for us to take accurate measurements. The positive crocodile clip will be clipped on to 0cm; the negative will be moved up and down the ruler accordingly. I will take measurements every 20cm, meaning that for each thickness of wire I will end up with 5 measurements. When the negative electrode is in place every 20cm, I will need to use the ammeter to check that the current is at 0.3, I ...

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