Factors Affecting Induced Electro-motive-force Essay, Research Paper
Planning Aim To find the factors that affect the amount of E.M.F. being produced. The amount of E.M.F. produced during the experiment when each type of factors is change. Background knowledge Electro-motive-force is the energy being supply to a charge. Battery is a type of energy. The energy that it provides is voltage. Battery voltage is sometime called electro-motive-force because it is used to “pump” around the electrons in the wire. The force can be generates by the moving of magnetic field as in the left-hand rules (field, current and force). It is the force that pushes the electrons around the circuit from the positive pole to the negative pole. That is why current directions in circuits are always marked from positive to negative. The voltage of the batteries varies in many volts e.g. 1.5V, 6V etc. A battery with a voltage of on volt is able to deliver one joule of energy for each coulomb of charge that passes through it. In other words, the voltage of a battery is the number of joules per coulomb that the battery can deliver when it is connected in a circuit. The law of left-hand rules or Fleming rules is that: * Thumb is for Motion. * First finger is for Field. * Second finger is for Current. Hypothesis * Does the change of frequency of the current affect the amount of electro-motive-force being produced? * Does the change of current affect the amount of electro-motive-force being produced? * Does the number of coil of green wire affect the amount of electro-motive-force being produced? * Does the number of coil of wire use for magnetizing the irons affect the amount of electro-motive-force being produced? Apparatus 1. AC power supply – provides electricity to the circuit. 2. Signal generator – for providing the electricity the circuit and also for changing the frequency of the current. 3. Ammeter – for measuring the amount of amp being produced. 4. Coil of wire – produce the magnetic field, which magnetize the pieces of iron. 5. Two pieces of iron – to be magnetized into a magnet. 6. Circuit wire – for connecting up the circuit. 7. Oscilloscope – for measuring the amount of electro-motive-force being produced. 8. Green wire – attached to oscilloscope carrying the electro-motive-force to it to be measure. Planning Safety precaution * Electricity is dangerous therefore be careful while connecting the circuit by having the power supply turned off at start. * Wire striper is sharp therefore while stripping careful not to cut your hand. * Too much current can made the wire to melt causing smoke and fire therefore tried to use the current as low as possible. * When magnetizing the iron careful not to put your finger between them because your finger will either be squash or cut. Method First I set up the apparatus as shown above. Then I plug a circuit wire to 0V and the other to the 2V then I turn on the ammeter follow by the power supply. I then look at the oscilloscope and measure the width and the height of the electro-motive-force wave. I record down the result and then I turn off the power supply. I change the circuit wires now to 0V and 4V. Then I do the same thing as I did before except that I change the voltage for every experiment from 0 and 4 to 0 and 6, 0 and 8 and 0 and 12. When I finish all that I have mentioned I then repeat all of them again in order to get the average results for each of the experiment. After I have finished repeating the experiments I then change from AC power supply to the signal generator. I plug the circuit wire to it and turn it on. Then after I it on I change the frequency of the current from 0Hz to 10Hz and I record down the width and the height of the electro-motive-force wave. When I finished I change the frequency from 10Hz to 20Hz and do the same thing as I did before except that I change the frequency for every experiment from 20Hz to 30Hz, 40Hz, 50Hz, 60Hz, 70Hz, 80Hz, 90Hz and 100Hz. Then when I finish I repeat all of them again so that I can get the average results for each of the experiment. When I have finished repeating the experiments I then change the signal generator back to AC power supply. I plug the circuit wires into the power supply at 0V and 6V but this time I will not vary the current but I will vary the number of coil of the green wire around the piece iron instead. First I have no coil around the piece iron and then I turn the power on and record down the width and the height of the electro-motive-force wave. Then I turn off the power and add one more coil on to the piece iron and turn the power on. Then do the same thing as before except that I change the number of coil of wire by increasing the number by one at the time until it reaches ten coils I stop. After that I repeat all of the experiment again in order to get the average results for each of the experiment. Planning Factors that will be included in the experiment * The frequencies of the current that will be vary when it is being tested. It will be vary every 10 Hz starting from 0 Hz to 100 Hz. * The current will be varying from the power supply. The current will be 0.25A, 0.5A, 0.9A, 0.11A and 0.31A. * Number of coil of the green wire will be change from 1 coil to 10 coils. Prediction What I have predicted the result will be is that for the change in voltage the amount of EMF produced will be proportional to the change of the voltage. For the change in the number of coils I predicted that the change in number of coils would be proportional to the amount of EMF produced and for the change in frequency of the current I predicted that as the frequency increased the amount of EMF produced also increase proportionally. Evaluation From the experiments I have done I think that the way I did them is the best way to carry them out. The method I choose to do to make the experiments as accurate as possible was to repeat each of the experiments twice. This also makes it a fair test and it also makes the results more accurate. In my experiment I do not think there are any errors that have occurred, this is because that there are no odd results on the graph that would stand out to be wrong. If I did the experiment again what I would do is that I would repeat the experiment on the change of frequency again. But this time with more accurate signal generator, and small and fine scale of oscilloscope. The other thing I would do is to do more experiments on other factors as well. For example the size of the magnet could also be changed, the magnetic field strength could be changed and the size of green wire could be changed. Analysis The best way to make the results become the most effective is to make a record of the results in the table so that they could be seen clearly and easy to spot. Also the best way to present the results as clear and as best as possible is to plot them on to the graph so that they could be seen clearly and easy to read. The graphs also need the best-fit line to go with them in order to make it clear for the analysis and to spot any linkage or relationship between the two sets of results. Variation on the amount of voltage From looking at the graph I could see that Variation on the number of coil In this variation I decided to change the number of coils around the iron, not for increasing the magnetic field strength of the iron, and recorded down the amount of EMF produced. By looking at the graph I could see that as the number of coils increase the amount of EMF produced also increased. The other word is that the change of number of coils in proportional to the amount of EMF produced. Variation on the frequency In this variation I decided to change the frequency of the current but not to change the amount of input current. The amount of current will be the same, in the experiments I decided to keep it at 0.01 A. From the graph it could be noticed that as the frequency increased the amount of EMF produced also increased as well. But at the beginning of the graph from 0 Hz to 10 Hz it could not be seen clearly though because that the best fit line that was drawn did not go through the origin therefore it could not be judge that the graph is totally correct though. This was because that at the beginning it seemed that the graph started of with the curve and eventually started to become straight line. The aftermath of the predictions For the prediction that I have predicted early on, it is indicated from that results collected, that all the prediction I have made are as expected. For the induced EMF in every case has changed proportionally to the factors according to the predictions. This could be seen clearly from the graphs. Conclusion What I have found out from the experiments is that for every factors of the experiment change the same conclusion was found which is that the induced EMF has change proportionally to the change of factors. No. of coilsCurrent (A)EFM reading in mV 1st2ndmean 10.03808080 20.04150140145 30.04220220220 40.04300310305 50.04380390385
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