• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Investigating how the length of a wire affects the resistance.

Extracts from this document...








The aim of my investigation is to find the relationship between the resistances of a wire at different lengths. An electric current in a wire is a flow of electrons and can be measured in amperes. Resistance is the natural property of all conductors to hinder an electric current.


In this investigation I will set up a simple circuit to read the voltage and current when the length of the wire changes. The length will range from 10cm - 60cm with intervals of 10cm. Moving the crocodile clip across the wire on a ruler will change the length of the wire. For each of these lengths I will find the potential difference across the wire length and the current flowing through it. I also decided that the best thickness of wire to use would be 30swg.This is because a thicker wire would cause too much heat, and the resistance of a thinner wire would be high and difficult to measure. The reason for this is that a thicker wire has less resistance, because there is more room for the electrons to travel through it.

The readings from the ammeter and voltmeter will be used to work out the resistance. This can be done using the formula: R = V/I (Ohm’s Law)                                                                                                                                                               V=voltage (Volts) I=current (Amps) R=resistance (Ohms)

Variables                                                                                  For this investigation I am going to have dependent and independent variables.

...read more.


The circuit should be set up as in the circuit diagram. It is important that the voltmeter is set up in parallel and the ammeter in series.





Preliminary work                                                                       I did a preliminary test as a trial of my investigation for the following reasons; to get an idea of the results and the range of value I would be working in, to get used to the equipment, to ensure that the wire did not get too hot, and to test the amount of cells to used in the circuit. The amount of voltage I used was important, as it would determine how hot the wire got. If the wire got too hot, energy would be given off as heat, and the resistance would have increased. I did a test that used the same piece of wire at different lengths with 1 and 2 cells. The results showed that with 2 cells, the resistance was higher due to the wire being hotter. For this reason I will use 1 cell to keep it a fair test. I needed to repeat the result for accuracy and reliability.

...read more.


Through out my investigation I found that I had anomalous results so I redid the test of 60cm, as the average resistance was 20.1 I found this result was too high to be reliable. This anomalous result could have been caused because of the wire heating up. I had a considerable amount of anomalous results, which lead me to feel that my results weren’t sufficient enough. Even though my results weren’t perfect, in that they don’t follow a set pattern, they do give me the information I need to prove my prediction. If I had to do the practical again I would improve it by keeping the current switched off for longer to ensure that the wire stays at the same temperature and repeating the readings more often. I would have also taped the ruler to ensure that it stayed in the same place and didn’t move. I also found that I could have used a copper wire instead of a Nichrome wire. However, Nichrome wire has more resistance but I would’ve had to do a further investigation to prove this. For further work I could have done an experiment to prove that Nichrome wire has more resistance than a copper wire.

...read more.

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

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Electricity and Magnetism essays

  1. Resistance of a Wire Investigation

    Fill the beaker with 450 cm3 of water and 50 cm3 of NaHCO3. Select 1 or 2 pieces of pondweed each roughly 5-10 cm long and cut off the stems. Place the pondweed in the beaker and secure the funnel upside down over (on top of)

  2. Investigating how the length of a Wire affects its resistance.

    This is because the repeat will show us the correct result (assuming the error is not present in all of the results taken). This is also why 3 results are the optimum amount that should be performed. If there was a seemingly anomalous result, 2 repeats would not allow conclusive proof that it was definitely wrong.

  1. Free essay

    Investigation: How length affects the resistance in a wire.

    drop, as the electrons have a larger area to flow through, thus there will be a smaller ratio of resistance, tot area. This will mean there will be a negative correlation between width and resistance. Strategy: To ensure that I have accurate and reliable results, I have devised a strategy, to make sure everything is done/set up properly.

  2. Investigate how length affects the resistance of a length of wire.

    increases then the resistance will also increase in proportional to the length. I think this because the longer the wire the more atoms and so the more likely the electrons are going to collide with the atoms. Therefore, if the length is doubled the resistance should also double.

  1. Investigation on Photovoltaic Cells

    To make my experiment fair I will used the same lamp so that the bulb does not have an effect on my results. I will also ensure that I used the same wires to connect my voltmeter to my solar cells, so that is there is a difference in the wires it will not effect the end result.

  2. Construct and test an anemometer.

    be able to produce a calibration curve for the relationship between potential difference created by the motor and wind speed. To record the rpm of the cups I had initially intended to use light gates, and to record three interruptions per revolution.

  1. "Are rechargeable batteries more economical than alkaline batteries?"

    It cost $1.36 per battery and usually cannot be purchased in bulk to reduce cost. In addition, following the observation during the trials, the brightness of the bulbs was disappointingly dimmed. In normal equipments for example, the need to change the battery is more vigorous than the 1.5V bulb.

  2. An investigation into how the resistance of wire is related to the length.

    is directly proportional to the voltage (V) applied if the temperature does not vary. As the voltage across a conductor is increased the electric current running through it increases in proportion. For any metal conductor at a constant temperature the resistance (R) is the same, it is not dependant on the current.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work