# The aim is to investigate how the length of a wire affects the resistance of a wire. The variables of the experiment will be the Length of wire.

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Introduction

Deepak Tailor

08/05/03

Resistance of a wire Investigation

Aim

The aim is to investigate how the length of a wire affects the resistance of a wire. The variables of the experiment will be the Length of wire.

Prediction

I predict that the longer the wire the higher the resistance. This is because the high number of free electrons which are colliding with other free electrons. Therefore, energy is lost due to these collisions. The energy is lost as heat. To calculate the amount of resistance for each length I used the formula: -

Restivity x Length of wire

Cross Sectional Area

To find out the restivity, I used this formula: -

1.7 x 0.00000001 = 0.000000017

P = 0.000000017

I measured the length of the wire in the experiment as :-

L = 0.2 Metres, 0.4 Metres, 0.6 metres, 0.8 meters, 1.0 metres

To find out the cross-sectional area of the wire, I first calculated the thickness of the wire. I know that the thickness of the wire is already 0.11 mm.

Middle

## Fair Test

To conduct the experiment I first had to make the experiment a fair test. I did this by keeping the power pack at the same voltage at all times. I also did not move or change any of the wires whilst conducting the experiment.

Method

Firstly, I set up the apparatus as shown in the above diagram. Secondly I switched on the power pack to run the electricity through the wires. Thirdly, I used the crocodile clips to make the length of the wire 0.2m long. I repeated this procedure changing the length of the wire to 0.4 m, 0.6 m, 0.8 m and 1.0 m. Next I recorded the current (amps) and voltage (volts) running through each of the lengths. To calculate the resistance of each length of wire in my experiment I divided the current (amps) by the voltage (volts). To ensure accuracy and reliability I repeated the experiment three times and noted the results.

Conclusion

A further experiment I could do would be to see whether the diameter of a wire affects the level of resistance.

Beal High School

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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