How The Length Of A Wire Is Affected By The Resistance
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Introduction To investigate how the length of a wire affects resistance in an electric circuit, different lengths of wire will be placed in an electrical circuit and the effects will be observed. An ammeter and voltmeter will be used to measure the current and voltage in the circuit. Then, resistance will be worked out by dividing the voltage by current. Resistance is the measure of how hard it is for electricity to push through a circuit. All conductors resist the flow of current to some extent. Howeaver, some resist more than others. The...
Overall, the experiment went well as the data fully supported the prediction, with the exception of one outlier (the average of the 50cm wire test). The prediction was based on the theory that the longer the wire, the further the current has to travel which gives a longer amount of time that the current is travelling against the ions creating resistance (as explained in further detail previously in the Introduction). The fact that the data supported the prediction shows that the experiment was carried out well with at least an adequate amount of accuracy as it produced the results expected.

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INTRODUCTION: In this coursework... INTRODUCTION: In this coursework investigation, I will be doing a series of experiments to see how changing the length of a piece of wire affects the resistance of the wire. PREDICTION & BACKGROUND THEORY: I predict that as the length of wire becomes longer, the resistance will become gradually bigger. A piece of wire is made up of several hundred atoms. An electrical flow is able to run through the wire, these are e- electrons. As the current increases the velocity of the e- electrons increases which increases the amount of collisions between the electrons and the atoms. This, in turn, creates a higher resistance. We know that if the current increases, the resistance does too. There are three factors which can affect the resistance of a wire, these are the length of the wire, the material it is made of and the area of the wire. The structure of the wire is show below, it is similar to a lattice structure with atoms in rows, packed quite closely together. = Atoms = Electrons As we can see from the diagram, the electrons will have to work harder to make their way through the piece of wire. PRELIMINARY WORK: To make sure I have done my research and preparation work correctly, I will do a preliminary experiment. This is like a "test run" to make sure I don't run into any major problems. Should a problem become apparent, I will be able to change it before I start to record my results of the experiment for real. I will record my results, however, to see if they look correct and in the right range. METHOD: a Set up apparatus in the following way b Set up wire in the appropriate way. i.e. choose correct length and put crocodile clips either side of chosen length c Ensure ammeter is set to "0". d Switch on power supply e Record results f Switch off power supply g Alter length of wire h Repeat steps "b" to "g" for remaining length of wire SAFETY PROCEDURES: a Switch off power supply between readings b Ensure wires are connected t power supply correctly c Ensure wires are safe "“ i.e. not bare or broken ACCURACY PROCEDURES: a Measure a certain length of wire in more than one place to see if you get a similar reading. b Always start experiment with Ammeter at "0" c Switch of power supply to allow wire to go cool for all readings PROCEDURE FOR FAIRNESS: a Use same equipment for all experiments i. Ammeter ii. Volt Meter iii. Wire b Allow wire to go cold before taking next reading. Temperature could cause changes. RESULTS: Length in CM Voltage Average Resistance V1 V2 V3 In W 5 0.5 0.2 0.1 0.3 3 10 0.7 0.3 0.2 0.4 4 15 0.9 0.4 0.3 0.5 5 20 1.1 0.5 0.4 0.6 6 25 1.2 0.6 0.5 0.9 9 30 1.4 0.7 0.6 1.2 12 35 1.5 0.8 0.7 1.0 10 40 1.6 1.0 0.8 1.1 11 45 1.7 1.1 0.9 1.2 12 50 1.8 1.2 1.0 1.3 13 Current = 0.1amp Wire = Nickel Chrome ANALYSIS AND EVALUATION From the graph overleaf, we can deduce that our prediction was correct. As the length of the wire increases, the resistance does too. We have noticed that two points don not follow this trend. This could be due to a flaw in the experiment, such as "we left the power on too long and caused overheating" or "we simply took a mis-reading". However, this does not happen for the majority of the readings so we have an adequate set of results to draw this conclusion. The results could be changed if we did things differently a second time around: - Changed current - Used different wire - Left the power on for longer Our prediction has been proved correct. As the length of wire increases the resistance gets bigger. They are proportional to each other in this case.   

INTRODUCTION: In this coursework investigation, I will be doing a series of experiments to see how changing the length of a piece of wire affects the resistance of the wire. PREDICTION & BACKGROUND THEORY: I predict that as the length of wire becomes longer, the resistance...

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Aim:- We will investigate... Aim:- We will investigate the length of a wire in a series circuit, and if it will affect its resistance. Prediction:- Resistance is the force of which opposes the flow of an electric current around a circuit so that energy is required to push the charged particles around the circuit. I predict the resistance will vary with the length. I also predict the longer the wire the less current will flow which increases the resistance. This is because electric current is the movement of electrons through a conductor, so when resistance is high, conductivity is low. Therefore, the electrons will have to push their way through a shorter path of atoms in the wire, reducing their resistance. Whereas, if the length was longer, then the number of atoms in the wire increase. Electrons are negatively charged particles, and protons are positively charged atoms. Electrons move around, but protons don't move, they stay in the same place. Current is a flow of electrons, and is measured in amperes A. When a current flows through a resistance, energy is given off as heat. I think the thicker and shorter the wire, the lower the resistance. I think this because, for example, if you had a road with cars parked to the side and only one car at a time can pass the cars parked on the side of the road as the road is so narrow that allows two cars to go at a time, but as it seems that there are cars parked, that only one car can move past the parked cars; in this case it will be slower for the cars to pass, because the road is long and narrow. Whereas, if the road was wider thinker and shorter it would be quicker. DIAGRAM OF THE THICKNESS AND LENGTH Planning:- Before I do start my investigation I will need to set up my circuit. I will need a variable resistor connected to a power supply, an ammeter and a voltmeter voltmeter parallel to the nichrome wire. I will move the knob on the variable resistor into five different positions for each one length e.g:- 10cm, 20cm, 30cm "¦"¦.. I will get five different readings for each length, and I will be doing five different lengths, which makes twenty-five readings all together, on the voltmeter and ammeter. I will calculate the resistance with this equation:- V = R x I OR Potential difference volts, V = Current amps, A x Resistanceohm, This is how my circuit will look like when I've finished setting it up:- DIAGRAM OF CIRCUIT I will link all the components together with the wire connected to the circuit with crocodile clips at the length of 10cm. I will use to measure the voltage using a voltmeter and recording the results on a table. I will also need to measure the current using an ammeter and recording the results for them too. When I have the results I require, I will use the calculator and divide the voltage by the current to get the resistance. I know that I will need to turn off and on the power supply every time I investigate another length of the wire. This is because the wire intends to warm up and this may have an effect on my other readings and also the wire can snap in half by melting. To keep my investigation fair, I will keep the voltage on the power supply the same, the type of wire and the thickness, and also do the investigation in the same surrounding temperature. Analysing:- I have calculated the resistance of each length on the nichrome wire. I have used these results of values to plot a graph of resistance against length. Length goes along the bottom axis because it is the dependent variable. Its value depends on the length of the wire chosen The points on my graph are a little scattered, none of the points touch the line of best fit, but they are quite close together.. On my graph of the length against gradient, I have rejected one point. I would of rejected two, but I have noticed that the 10cm point was very high, I was going to also reject the 40cm point too, but I was more curious on the 10cm. my table of results suggests that the voltage reading for one point in the 10cm trial was very high compared to the other results of 20cm, 30cm, 40cm and 50cm. but I reckon that I must of miss read the meters whilst investigating. I have noted my working out on the graph of current against voltage. On my graph of current against voltage, there is an anomalies point which I have circled. It is the 10cm point of 0.90V and 0.18A which I must have rejected on the graph of length against gradient. So this is the reason of my rejection on the graph of length against gradient. You can see that this one point has affected the gradient. And as I mentioned that I must of miss read the meters.   

Aim:- We will investigate the length of a wire in a series circuit, and if it will affect its resistance. Prediction:- Resistance is the force of which opposes the flow of an electric current around a circuit so that energy is required to push the charged...

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