An investigation into how the strength of an electromagnet is affected by varying the current
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An investigation into how the strength of an electromagnet is affected by varying the current Introduction I am investigating whether, and if so, how an electromagnet is affected by varying the current. An electromagnet is a magnet created by winding a wire around a soft iron c-core and running a current through the wire. Current is measured in Amperes (A). Variables available Voltage Current ·N0 of coils around the c-core Size of the c-cores (thickness/length) Type/size of the wire coiled around the c-core I chose to use current as my variable. I decided this because I have access to accurate equipment to measure the current, when I change it. The other available variables will be kept constant throughout the experiments. Aim I aim to find how varying the current in an electrical circuit affects the strength of an electromagnet. Background Scientific Knowledge My c-cores that I will be using will be ferromagnetic, meaning that it quickly becomes demagnetised when the current is switched off and that it is very good at increasing the strength of the magnetic field produced by the current in the wire. To become magnetic in the first place, the electrons in the c-core (the one with the wires around)
I will use the voltmeter so that when the voltage changes, due to resistance, I can correct it on the power pack. I will use 6 different levels of current (1,2,3,4,5 and 6 amps) and I will repeat each experiment once and the take an average to help make a fair test with reliable results. This will give me a good range of results, which can be plotted on a graph, so they will be easy to analyse. Analysis (GRAPHS NOT AVAILABLE). My results are good. They are what I basically expected (strength of electromagnet increased as the current increased. My graphs have shown this, and they each show a good curve of results. I have included a graph of my results, a graph of my found pattern results and a graph to compare these two curves. My results don't fit my prediction. This may have been due to the fact that my prediction wasn't researched thorough. I may have one or two anomalous results. For example, the first result seems to be very low, and there is a big difference between both of my results at 4A. I will be able to discover which are the anomalous results when I come to find a pattern in my results.
This means that I would be less likely to make a mistake. Also, I would have liked extra time, so that I could take an average of 3 results, which would make the average more accurate. If I had extended time, I could investigate the experiments further, and get more accurate results. I would like to have done more experiments with a higher current. This would mean that I could investigate the saturation theory, and whether beyond a certain point, it does not matter how much you increase the current, the electromagnet will not get stronger. Also, I could mathematically prove my theory about the current directly affecting the electromagnets strength, due to its increase in power. I could measure the gradients of the graph to find the exact increase in strength between each measurement. It would also be useful and interesting to see whether the heat of the variable resistor affected the results. My anomalous result could have been due to the variable resistor being cold, during the first experiment, when all of the equipment was cold. I would also like some extra time to do some proper research into the findings of the first people to test this investigation. It would also be interesting and useful to discover what they found. Acknowledgements Encarta '98 The Cambridge Encyclopedia Amperes theory web page for engineers
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