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# EMF Investigation.

Extracts from this essay...

Introduction

EMF Investigation Planning Aim and hypotheses According to Fleming's Rule, electricity is generated when movement occurs in the magnetic field. Alternatively, switching direction of the magnetic field also works. Alternating current is a good way of alternating the field direction. The electricity generated, of in the other words, the electromotive force, is measured in volts. By varying different parts of the apparatus, the EMF output could also vary. The aim of this investigation is to establish a connection between the factors and the output. Possible factors that could be altered in a general apparatus are: * Frequency of field alternation * No of coil of wire in the magnetic field * Strength of magnetic field, varied by * - size of electromagnet * - current used to establish and maintain the magnetism of the electromagnet * - no of coil used to magnetize the electromagnet * Moving the wire in the magnetic field A preliminary experiment, with the same apparatus used, is done earlier on and some useful information was acquired from it. As it was mentioned that alter the direction of the field generates electricity, and it was found out in the preliminary experiment that the more frequent that the field is altered, the quicker would electricity be generated, so by looking at different frequency, perhaps a pattern indicating the relation. In an experiment involving generating movement by electromagnet, the more wire coiled through the motor, the faster the movement would be.

Middle

So if the current and field are the inputs and the movement is the output, this process should be reversible. If the movement is put in and the field stays constant, current, or electricity, should be generated. Moving a wire in a magnetic field could do this. If the wire is connected to a galvanometer or a device that detects electricity, small electrical reading should be picked up. However this process is not efficient, as much of the energy input is lost, for example in form of heat, so this process is not popular at all in reality. Another possibility is that the direction of the magnetic field could be altered and this should create similar effect with more efficiency. This way, the power supply that maintains the magnetism of the magnet has to be switched on and off rapidly in order to make the current generated worthwhile. Using alternating current of AC power supply normally does it, as it changes direction every so often. Domestic electricity alternates at 50Hz, which means 50 times per second. This process, when compared to the latter, is much more efficient, as not as much energy is lost during the conversion, and the device needed to flicker the current is not as sophisticated as the one needed to move the wire around the field, and it is more easily done. Evaluation This experiment has worked well and has finally produced sufficient results that a meaningful conclusion could be deduced from it.

Conclusion

After a study, it has been revealed that the circuit used contains so many built-in errors that cannot be helped. These factors are: * Eddie current inside the magnet itself; * Flux being lost on the corners of the magnet; and * Resistance of the wire. This is the only valid explanation for the difference from the obtained results and the calculated results. The formula is accurate given that the efficiency of the circuit is 100%, but in this case, it is not. Nevertheless, all that were predicted happened in the experiment. Some gives unprecedented results, but they all turn out with patterns within them. They seem to be accurate to a certain extent, as they all fit in their own patterns, despite the peculiar turnout of the frequency graph. Mathematical Prediction Strength of Magnetic field Voltage input Coil in Magnetic Coil magnetizing EMF induced inV in V Field electromagnet calculated configured obtained configured 2 1 240 0.008 0.024 0.060 0.021 4 1 240 0.017 0.047 0.120 0.042 6 1 240 0.025 0.071 0.180 0.064 8 1 240 0.033 0.094 0.240 0.085 10 1 240 0.042 0.118 0.300 0.106 12 1 240 0.050 0.141 0.360 0.127 Coils inside magnetic field Voltage input Coil in Magnetic Coil magnetizing EMF induced inV in V Field electromagnet calculated configured obtained configured 4 1 240 0.017 0.047 0.178 0.063 4 2 240 0.033 0.094 0.358 0.127 4 3 240 0.050 0.141 0.538 0.190 4 4 240 0.067 0.189 0.715 0.253 4 5 240 0.083 0.236 0.895 0.316

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