# Electricity Coursework.

Extracts from this document...

Introduction

Jonny Green 10GU

Electricity Coursework

## Aim

For my coursework in electricity we have been given the task to investigate and experiment with circuits. We need to investigate the rates at which resistance increases. I have decided that I am going to investigate the different lengths of copper wire and find out what lengths increase or decrease the rates. My aim is to find the best length of wire to produce the highest resistance which will make the highest current.

## What Is Resistance?

## Resistance is where there is a component or components that resist the flow of current through them. Resistance increases when a current that flows. Resistance is a measurement of how difficult it is to get a current through a component at particular potential differences or at particular voltages. This is how you work it out-

potential difference (volt, V) = current (amps, A) x resistance (Ohm)

### How Is The Resistance Measured?

The resistance of a length of wire has to be done by calculating the current and voltage. I must measure the voltage across the wire (in parallel) and the current present in the circuit (in series). These measurements are then made into a formula to work out the sum. This is what it looks like-

voltage (V) = current (I) + resistance (R)

#### This is what is called Ohm’s Law.

Middle

In class been discussing the best methods to increase the resistance I have learnt that the if you increase the voltage the resistance increases, as there the wire will be hotter and therefor giving off more heat. Using all this information I am going to predict that the longer the copper wire the bigger the resistance.

Safety

When I do the experiments I will have to work with voltage which will be dangerous. In order to be protected I must wear be very careful when I’m moving the wires so have to do it in a safe place so I can concentrate. Once the voltage is on the current through the wire is going to make it very hot so I won’t be able to touch it once it’s on. To make it even safer I will keep the voltage on 3 volts. I decided not to do lengths of wire shorter than 10 centimetres because it could overheat.

Diagram

This is what my set up of the equipment will look like-

Plan

To get the right results for my investigation I must experiment with different wire lengths to see the best result for the resistance.

Conclusion

Evaluation

My experiments went very well, I found the right evidence to prove my prediction to be correct. I think my results were pretty accurate from looking at my graph because the pattern of results flows very well with a positive correlation. The only results that don’t really fit the pattern were the lengths 35 – 40 because it takes the flow out of the graph. I think these results are very reliable because they prove that if you increase the length of the wire you will also increase the resistance. I think that my results are reliable enough to support my conclusion as I have written about all the things that could be noticed about the results. If I did this experiment again I would like to investigate the rate at which resistance increases as you change the thickness of the wire. This would be interesting to do because it would simply follow the same rule as the lengths- the longer the wire the bigger the resistance. In my experiment I found out that the longer (bigger) the wire the higher the resistance and if there is a thicker (bigger) piece of wire it should apply the same rule as they will both have larger area’s rather than a small or thin piece of wire. As this test is very similar I would predict the same results and this could also prove the theory of lengths and thickness to have an effect on resistance increasing.

This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

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