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

Investigation to show how the length of a wire affects the resistance.

Extracts from this document...


Investigation To Find Out What Factors Affect The Resistance Of A Wire.


To investigate and find out how the resistivity of a wire is affected by altering the lengths of constantan wire.


The longer the piece of wire, the greater the resistivity.  This is due to the idea of free moving electrons being resisted by atoms in the wire.  In a longer piece of wire, there would be more atoms for the electrons to collide with and so the resistance would be greater.  The relationship between the wire length and the resistance should be directly proportional.

For example if I had a 30 cm wire and a 60 cm wire, the 60 cm wire would have a resistance twice that of the 30 cm wire.  This is because in a wire twice the length there would be double the amount of atoms colliding with the electrons, and therefore causing twice as much resistance.  

The resistance can be calculated by using the formulae:


Resistance is measured in ohm’s (Ω); Voltage in Volts; Current in amps.

        Flow of electrons.

  1. Electrons colliding in to atoms causing energy to be lost in the form of heat, and resulting in the increase of the resistance.

Flow of electrons.

...read more.


Then work out the resistance by using the formulae V/I=R (Voltage/Current = Resistance).Plot graph to show average current against the wire length.Plot graph to show average resistance against the wire length.

Fair test.

  • The same voltage was used for each experiment (2 volts).  This was done by using a variable resistor.
  • The same piece of constantan wire was used for each experiment.
  • The same voltmeter was used.
  • The same ammeter was used.
  • The same power pack was used.
  • The same connecting wires were used.
  • The power was left on for the same amount of time (30 seconds).
...read more.



The experiment proved to be a success and I retrieved an accurate set of results although some results were not as accurate due to faulty/damaged voltmeters and ammeters.

Measuring the lengths of the wire was also an inaccuracy as the rulers used were not exact, and it was difficult to get an accurate reading of length by eye, as the wire may not have been completely straight.  These would have also contributed to the error. These results would be difficult to improve on as they are reasonably accurate, and there were no anomalous results.

If I were to do this experiment again, I would use newer, more accurate ammeters and voltmeters, a more accurate method of measurement, and take a much wider range of readings, and more readings so that a more accurate average can be taken.  I would also investigate other factors, such as temperature, voltage and current, and see how these affect the resistance.  I would also use a different type of wire thickness etc. and see what difference that would make to the resistance which would make it much more interesting.

As these results had a range of only 5 readings, from 0-50cm, and were only repeated three times, I would say that these results are not strong enough to base a firm conclusion on because there are so many potential sources of errors.

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

    This is ____2_-_1_ which is the same as is Different in x axis 0.6 - 0.3 calculated before. This means that the gradient is the constant. This is very important because it means that to calculate the resistance according to this constant, one needs to have results which form exactly the same gradient that has been obtained here.

  2. Resistance of a Wire Investigation

    The reason that light intensity does affect the rate of photosynthesis is because as light, and therefore energy, falls on the chloroplasts in a leaf, the chlorophyll, which then makes the energy available for chemical reactions in the plant, traps it.

  1. An in Investigation into the Resistance of a Wire.

    When there was a current running through the circuit and there were exposed wires for example the clips I did not touch them because this could be very dangerous because there is electricity going through them. I also did not touch the experiment wire because it could be hot due

  2. Free essay

    Investigation: How length affects the resistance in a wire.

    Therefore using cm means that this problem can be overridden. I will now test the formula to find the approximate resistance on a 0.8m (80cm) wire. It is predicted that the resistance will be 2.16 for this length, in accordance with my graph R = 0.27 x 80cm/10 This all amounts to R= 2.16 .

  1. The aim of my investigation is to investigate how length affects the resistance of ...

    I decided to go down in ten centimetre gaps, as it would allow me to lot a graph of resistance against length with a range of fie readings. Results As shown below there is only a range of five readings, which start to show a pattern, that the best fit line is directly proportional.

  2. Investigating The Characteristics Of A Filament Lamp

    In order to investigate the characteristics of a filament lamp, a simple circuit could be set up in order to discover how much the current in the circuit changes as the voltage is altered. From these two results, Ohm's law could be employed to work out the resistance.

  1. Investigating resistance when altering thickness of wire / length of wire

    60 0.90 0.90 0.40 0.30 2.80 40 0.90 0.85 0.50 0.40 1.94 20 0.70 0.80 0.80 0.75 0.94 Experiment 2 Thickness (mm) Area (mm2) V1 (volts) V2 (volts) A1 (amps) A2 (amps) Resistance 28 0.36 0.107 0.8 0.8 0.61 0.59 1.3 0.29 0.066 0.9 0.9 0.49 0.51 1.8 0.32 0.25

  2. Resistance in a Wire Investigation

    The length will be from 0cm-100cm going up in 20cm intervals. I will also use crocodile clips to connect the wire to the multimeter. When measuring resistance in the length of the wire the independent variable is the length of the wire and the dependant variable is the resistance.

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