# Resistance of a wire.

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Introduction

Science Coursework

Resistance of a wire

Plan

An introduction to the resistance of a wire.

I would assume resistance occurs because the electrons travelling along the wire collide with the atoms of the wire. These collisions slow down the flow of electrons causing resistance. Resistance is a measure of how hard it is to move the electrons through the wire. The current is the flow of electrons; the current is dependant on the amount of voltage, which is applied. Voltage is the push given to the current. If the length of the wire is increased then the resistance will also increase as the electrons will have a longer distance to travel and so more collisions will occur. Due to this the length increase will be proportional to the resistance increase. I assume this because the longer the wire the more atoms and so the more likely the electrons are going to collide with the atoms. The increase in length is the increase in resistance, because the increase in length will increase the number of atoms resulting in the increase of collisions slowing the electrons down and increasing resistance.

There are more factors which affect the resistance, the other one I will discuss is the width of a wire. If the wire width is increased, the resistance will decrease. This is because of the increase in the space for the electrons to travel through.

Middle

V=0.33

I=0.16

R=2.06

V=0.38

I=0.16

R=2.38

V=0.40

I=0.16

R= 2.5

4 strands

V=0.14

I=0.41

R=0.34

V=0.27

I=0.41

R=0.85

V=0.36

I=0.41

R=0.87

V=0.41

I=0.41

R=0.99

V=0.50

I=0.41

R=1.21

V=0.63

I=0.41

R=1.53

V=0.71

I=0.41

R=1.73

V=0.75

I=0.41

R=1.85

V=0.80

I=0.41

R=1.95

V=0.84

I=0.41

R=2.05

5 strands

V=0.12

I=0.40

R= 0.3

V=0.13

I=0.40

R=0.33

V=0.19

I=0.40

R=0.48

V=0.25

I=0.40

R=0.63

V=0.30

I=0.40

R=0.75

V=0.36

I=0.40

R=0.9

V=0.42

I=0.40

R=1.05

V=0.48

I=0.40

R=1.2

V=0.54

I=0.40

R=1.35

V=0.69

I=0.40

R=1.77

6 strands

V=0.04

I=0.40

R=0.12

V=0.07

I=0.40

R=0.19

V=0.11

I=0.40

R=0.27

V=0.15

I=0.40

R=0.38

V=0.18

I=0.40

R=0.46

V=0.20

I=0.40

R=0.5

V=0.26

I=0.40

R=0.65

V=0.31

I=0.40

R=0.77

V=0.35

I=0.40

R=0.88

V=0.37

I=0.40

R=0.92

2nd set of results

Length/ Thickness | 10 cm | 20 cm | 30 cm | 40 cm | 50 cm | 60 cm | 70 cm | 80 cm | 90 cm | 100 cm |

1 strands | V=0.52 I=0.66 R=0.79 | V=0.95 I=0.66 R=1.44 | V=1.48 I=0.66 R=2.24 | V=1.92 I=0.66 R=2.91 | V=2.40 I=0.66 R=3.64 | V=2.89 I=0.66 R=4.38 | V=3.35 I=0.66 R=5.08 | V=3.82 I=0.66 R=5.79 | V=4.27 I=0.66 R=6.47 | V=4.78 I=0.66 R=7.24 |

2 strands | V=0.30 I=0.66 R=0.45 | V=0.52 I=0.66 |

Conclusion

Stacey Owen

Candidate no: 0126

Hampton Community College

Science Coursework

Resistance of a wire

Evaluation

The evidence I obtained has helped me to come to my conclusion the previous page. My results show quite definitely that as depth increases the speed increases. I’m happy with the accuracy of my results for two reasons:

- The results follow my prediction exactly.
- All the points are close to the line of best fit.

I could have made my experiment if I had taken more sets of readings, I would have obtained a better average.

I’m pretty pleased with the suitability of my experiment for the following reasons.

- I was able to get to good and valid sets of results using the equipment and time allowed.
- I made sure the test was as fair as possible.

There was one anomalous result but apart from that they all followed the correct pattern and my prediction. The anomalous result was from the first set of results, there was a lot of difference between the 1 strand results and 2 strands result; this may have been because this was an extra thin wire compared to the others. Therefore I’m happy that my evidence is accurate a reliable enough to support my conclusion.

To Improve and extend this investigation I could use the same method to investigate a greater range of input variables e.g.

- Temperature
- Bigger range of distances
- Different materials

Stacey Owen

Candidate no: 0126

Hampton Community College

This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

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