Physic Sc1 Resistance Of A Wire

How the foe of a equip changes with divers(prenominal) aloofnesss Planning We ar threatening to find turn up if and how the guard of a conducting conducting equip changes by adjusting the continuance of the tele interpret. I conjecture that as the distance increases; the bulwark testament also increase. I value this lick up s sticks happen beca subroutine in previous samples, my results give suck shown this. For example: I sp eradicate a penny d peerless an experiment where I had to find out what vari commensurates unnatural the electrical protection of a outfit. I lap up a circuit similar to the bingle in the plot below. But instead of keeping on the whole the vari fittings the corresponding, I changed them, unrivaled at a time, to go out what issuance they may put off on the shield of a wire. Predicted Graph                                                   Â Â Â Â                   Circuit plot The apparatus I depart use is: battery pack, leads, ammeter, constantan wire (0.25 mm), ruler, crocodile browse and a voltmeter. I did a useable in which I chose to use constantan wire. It provided me with a nice range of results. This led to my decision to use constantan wire in my probe. thither are a few venture canal in which I want to make this investigation fair. at that place are four variables. They are: total of trustworthy, temperature, diameter and length of wire. In order to gain the results to what I am trying to find out, I must keep all the variables the analogous apart from the length. I leave non alter the come up of cells that I use, as this leave behind affect the current, and therefore it will affect my foe result. I will magnetic discus the results of all(prenominal) length, and ?break the circuit quickly. By ?breaking the circuit I mean disconnecting matchless o f the wires. This will reduce the chance of! getting a ? oestrus system effect. The ?heating effect is an effect that temperature has on the wire. It occurs when there is also such(prenominal) current aerodynamic with a resistance wire. As the wire becomes hotter, the atoms in the metal vibrate faster. This makes it harder for ?free electrons to apply out with the wire. This is because the electrons collide with the atoms. This is called ?collision theory. It can be compared with a mortal die hardning through a corridor fresh of plenty. If the people (atoms) are still, then it is relatively easy for the soul to run through; but if the people are moving, then it is harder for the person to run through. Due to this, the resistance goes up. Due to an experiment that I did last year, I know that changing the diameter of a wire, changes the amount of current that can go down through it. The thicker the wire, the to a greater extent current can flow through it. at that placefore it is historic to keep t he diameter and pillowcase of wire the similar. In close to wires there are more ?free electrons i.e. more current can flow through it. There is departure to be one calculation that I will need to do after I see obtained my results. I will postulate obtained look atings for current, length and voltage. In order for me to come to a aware conclusion, I will need to know the relationship amidst safeguard and Length of wire. In order for me to be able to calculate the enemy, I will need to apply a calculation to my results. That calculation is: resistance = Voltage Current. I am going to plot my results on an X-Y scatter representical record development a communication channel of best fit to be able to read the graph more clearly. I am going to set up a circuit as shown in the diagram. I am using 3V in my battery pack. I will use the ammeter to record the current. The current must carry on constant. The rippled arguing is the resistance wire. I will set up a voltmeter in parallel to the resistance wire! . bingle end of the lead connected to the voltmeter will be unflinching and the other lead will be plugged into a crocodile clip which I will clip onto the resistance wire at 10 cm intervals, mea legitimated along the ruler. physics Coursework Friday, 09 March 2001 Alex hallway (J) How the resistance of a wire changes with distinguishable lengths Obtaining Evidence In order to gain a undecomposed range of results, I decided to repeat the experiment third times and take an number. I pretend plotted the average resistance results against the dissimilar lengths. In order to make the graph clear, I have decided to use increments of 10 cm from 0 cm up to one C cm of length. This makes sure that the results are accurate. In each of the three tests, the resistance results have been roughly the same for each length. For example: 80 cm of wire gave voltage readings of 1.63V, 1.63V and 1.65V. That is an average of 1.64V (3 real figures). This makes the m clear to read sour the graph. bear witness One Length of Wire (cm)         P.d. crosswise wire (V)          exemption ( ) 100         2.14         13.38 90         1.85         11.56 80         1.63         10.19 70         1.42         8.88 60         1.16         7.25 50         1.00         6.25 40         0.80         5.00 30         0.61         3.81 20         0.41         2.56 10         0.21         1.31 0         0.00         0.00 sort Two Length of Wire (cm)         P.d. crosswise wire (V)         Resistance ( ) 100         1.97         12.31 90         1.77         11.06 80         1.63         10.19 70 !         1.45         9.06 60         1.25         7.81 50         1.05         6.56 40         0.84         5.25 30         0.64         4.00 20         0.47         2.94 10         0.28         1.75 0         0.00         0.00 evidence Three Length of Wire (cm)         P.d. crossways wire (V)         Resistance ( ) 100         2.08         13.00 90         1.86         11.63 80         1.65         10.31 70         1.44         9.00 60         1.23         7.69 50         1.04         6.50 40         0.84         5.25 30         0.64       Â Â Â 4.00 20         0.43         2.69 10         0.23         1.44 0         0.00         0.00 reasonable Results Length of Wire (cm)         P.d. across wire (V)         Resistance ( ) 100         2.06         12.

88 90         1.83         11.44 80         1.64         10.25 70         1.44         9.00 60         1.21         7.56 50         1.03     Â Â Â Â Â 6.44 40         0.83  Â!  Â Â Â Â Â Â 5.19 30         0.63         3.94 20         0.44         2.75 10         0.24         1.50 0         0.00         0.00 natural philosophy Coursework Friday, 09 March 2001 Alex Hall (J) How the resistance of a wire changes with different lengths Conclusion The constantan wire that I utilise in my investigation could be described as ohmic. Ohmic in the sense that it follows Ohms law. Ohm tell that ?for some conductors, the current flowing is proportionate to the voltage, provided the temperature remains constant. This is received for my results. I drew a line of best fit to make it easier to read the results off the graph. I take that the speed of my recordings, contributed towards the straight line. Temperature is one of the variables that affects the resistance of a wire. I recorded my results instantly to reduce the possible swear out of temperature rising. For details, see prediction. I predicted that as the length increases, so would the resistance. I could have been more in truth(prenominal) and utter that the resistance was instantly proportional to the length. In my original prediction I said that the graph would be a straight line and non a curve. If the graph were a curve then we would have to expect that the wire heated up. This is because as the wire gets longer, the resistance increases, but it is not only that change. The ?heating effect also changes it. The resistance will go up. Physics Coursework Friday, 09 March 2001 Alex Hall (J) How the resistance of a wire changes with different lengths Evaluation I think that this experiment went well. I got accurate results and an expected graph. My results were reliable and expected. Everything went bewitching but I could maybe improve on the the true in the cutting of the wire and the recording of the amps and volts . A secure reckoner could be employ to gain accur! ate results. There may be some way for a computing machine to record the current and voltage readings accurately. I rounded my results to 3 satisfying figures. I may get more precise results by rounding to 7 or 8 significant figures. but this may look untidy, when put into a table. I think that my results are a good set of results and I would assert on them to be correct in the future. There is something that I would add to my method. That is a thermometer. If I was to take temperature very seriously, I could check to see if the wire stayed at the same temperature. If I repeated this experiment, I would prefer to plot a graph with twenty points on it, rather than ten. Therefore I would return the change in wire length to 5cm intervals. I could do some further research on the effect that the diameter of the wire has on the resistance. In my investigation, I used the next references: -Physical Processes Text Book -www.gcsescience.co.uk -www.homeworkresource.co.uk If you want to get a full essay, order it on our website: BestEssayCheap.com

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