# To find out how the length of a piece of wire effects the resistance

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Introduction

SarahWright10 T5thFebruary2002

Aim

To find out how the length of a piece of wire effects the resistance.

Introduction

We have been asked to investigate how the length of two different pieces of wire, Nichrome and Constantin effects the resistance. These are both metal alloys and they both conduct electricity. Metals conduct electricity because the atoms in them don’t hold on to their electrons very well, so allowing electrons to move carrying a negative charge along the wire. Resistance occurs when it is difficult for the electrons to be released from their nuclei to continue along the piece of wire.

Some variables that could have an effect on the resistance of the piece of wire is the thickness of the piece of wire, the length, the temperature, what the wire is made from, whether or not there is a kink or bend in the wire, and if the wire is short circuiting its self.

Straight

Not Straight

Kinked

Short Circuiting

If the piece of wire is thin then it will have a higher resistance because the current will not have as many different paths to go down making the electrical flow slower.

Middle

0.80 a

3.7 Ohms

0.8 m

3 v

0.80 a

3.8 Ohms

0.6 m

2.92 v

1.05 a

2.8 Ohms

0.6 m

2.98 v

1.03 a

2.9 Ohms

0.6 m

2.95 v

1.06 a

2.8 Ohms

0.4 m

2.85 v

1.55 a

1.8 Ohms

0.4 m

2.80 v

1.52 a

1.8 Ohms

0.4 m

2.79 v

1.50 a

1.9 Ohms

0.2 m

2.45 v

2.71 a

0.9 Ohms

0.2 m

2.42 v

2.70 a

1.2 Ohms

0.2 m

2.40 v

2.69 a

1 Ohms

Results (Nichrome)

Length | Voltage | Current | Resistance |

1 meter | 2.45 Volts | 2.20 Amps | 0.9 Ohms |

1 m | 2.65 v | 2.22 a | 1.2 Ohms |

1 m | 2.36 v | 2.10 a | 1.1 Ohms |

0.8 m | 2.25 v | 2.40 a | 0.9 Ohms |

0.8 m | 2.17 v | 2.26 a | 1 Ohms |

0.8 m | 2.32 v | 2.40 a | 1 Ohms |

0.6 m | 2.13 v | 2.70 a | 1 Ohms |

0.6 m | 2.10 v | 2.80 a | 0.8 Ohms |

0.6 m | 2.12 v | 2.76 a | 0.8 Ohms |

0.4 m | 1.91 v | 3.50 a | 0. |

Conclusion

Evaluation

Most of the results from this experiment are quite accurate. There is the odd result here and there which is not quite in place for one reason or another. Maybe I miss calculated it when I was working out the average or the resistance. Other than that most of them are quite accurate. I took the necessary precautions to make sure that the experiment was as accurate as it could be and that it was safe. I am afraid I am unable to explain the odd results in my tables. There is one that is quite shocking and that is the resistivity result. Unfortunately I am not sure why it is out of place.

The only problem I had with the original method was trying to keep the wire straight and not letting it short circuit its self.

In all I think I produced some good quality results that are fairly reliable. If I were to do this experiment again I would use more lengths that just 0.2, 0.4, 0.6, 0.8, and 1 meter. I would use measurements in between like: 0.3 and 0.5 meters as well. I would do this so that I would have a better idea of the shape of the graph and where to put the best fit line.

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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