Does the length of wire effect resistance
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Introduction
Michael Hyatt
Does the length of wire effect resistance?
Theory
Electricity is conducted through a conductor, in this case wire, by means of free electrons. The number of free electrons depends on the material. The more free electrons in a particular metal means that it is a better conductor. The better the conductor the less its resistance. Gold has more free electrons than iron and, as a result, it is a better conductor. Free electrons are given energy and move because of electromagnetic currents. Movement of these free electrons means that they will collide with neighbouring free electrons. This happens across the length of the wire and thus electricity is conducted. Resistance is the result of energy lost. It involves collisions between the free electrons and the fixed particles of the metal, other free electrons and impurities. These collisions convert some of the energy into heat.
Investigation
To find out how resistance changes if the length of a wire in changed.
Prediction
Middle
- Turn lab pack on and turn to the appropriate voltage.
- Record the reading on the ammeter in a table
- Repeat this for up to 5 volts and all lengths of wires.
Current (A) | ||||||
Voltage (V) | 10cm | 20cm |
Conclusion
Evaluation
I think that my method was very good. I used the equipment safely and correctly. My results are very reliable because of the fact that they lie on the trend line in all wire lengths. I did not foresee any problems with the experiment during my method and did not encounter any problems when carrying out the experiment. If I were to investigate this subject further, I could try to find out how metal type and cross sectional area affect the resistance of the wire. For my results to be more reliable, I need to maintain the temperature of my wire. To do this I would need to insulate all of the wires very well and conduct the experiment in a controlled temperature environment. I would need to conduct the experiment with a variety of different metals to determine just how much length affects resistance however; I think the results would be very similar.
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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