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Resistance of a Nichrome wire.

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Introduction

Chris Johnson 11D Candidate number 7055 Resistance of a Nichrome wire Introduction In this piece of coursework I aim to find the effects of length on a piece of nichrome wire. Resistance is a force which opposes the flow of an electrical current, this is why energy is needed to push the particles around. The circuit also contains its own resistance if the wires vary in thickness, a thin wire has a high resistance as there is less room for the particles to move and a thick wire has a low resistance because the particles can move around very easily. It's also measured in ohms. George Ohm discovered that the emf (Electro motive force) is directly proportional to the current, this means if you double one you double the other. ...read more.

Middle

I chose to take the readings in ten 10cm gaps. I placed a crocodile clip at each measurement and record the resistance three times for an accurate average and then put the averages on a graph. Circuit diagram Results table To make sure of a fair test I am going to do the test 3 times and then plot a mean on a graph. Length Pd(v) Current (I) Resistance(V/A) 100 0.73 0.05 14.6 90 0.652 0.05 13.04 80 0.58 0.05 11.6 70 0.51 0.05 10.2 60 0.44 0.05 8.8 50 0.365 0.05 7.3 40 0.295 0.05 5.9 30 0.231 0.05 4.62 20 0.159 0.05 3.18 10 0.87 0.05 1.74 0 0.012 0.05 0.24 Length Pd(v) Current (I) Resistance 100 0.73 0.05 14.6 90 0.655 0.05 13.1 80 0.575 0.05 11.5 70 0.51 0.05 10.2 60 0.463 0.05 8.72 50 0.363 0.05 7.26 40 0.296 0.05 5.92 30 0.226 0.05 4.52 20 0.155 0.05 3.1 10 0.084 0.05 1.68 0 0.015 0.05 0.3 Length Pd(v) ...read more.

Conclusion

I know this because my graph does not show any anomalies, this is because the graph is a straight line with no bulges or severe direction changes. There are several changes I could make to ensure better results were gained. - When I was measuring the lengths of wire, my measurements might have been inaccurate, as the rulers used might be slightly varied and not exact. It was difficult to get an accurate reading of length by eye, as the wire was not completely straight or flat, these could have caused slight variations in my results. But not affected them too much. Other variables that could be changed are - * Temperature of the wire * Diameter of the wire Overall the experiment went well and my results were good, and clearly prove my hypothesis. 1 5 1 ...read more.

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