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

An Experiment to Find the Effect of Length of Wire on It's Resistance

Extracts from this document...

Introduction

An Experiment to Find the Effect of Length of Wire on It’s Resistance

Background Information

Resistance, Ohm’s law; the current through a metal wire is proportional to the difference across it (providing the temperature stays constant).  Current – the flow of electrons around a circuit, Voltage – the electrical pressure within that circuit. Using this information, I know that; to find the resistance of a wire we simply divide voltage by current         ( R = V  ).

                                   I                

Knowing this, I can find the resistance quickly, and come to a conclusion faster on the affect of length of wire on the resistance. Resistance is the amount electricity is slowed down whilst passing through a conductor. It is slowed down by the electrons repelled by the power supply, colliding with ions. Copper has a different ion arrangement and, a low resistance, this also renders copper useless for this experiment. The two options for wires in this experiment are, nichrome and constantan.

            For a flow of electrons there needs to be a circuit. A complete circuit needs electrical conductors, metals are good conductors because they have free electrons which can leave the atom and move around the circuit. When atoms lose or gain electrons they gain a charge, and are subsequently then called ions.

...read more.

Middle

1                                0.05                                20.00

40 cm CONSTANTAN

5                                1.43                                3.49

4                                 1.13                                3.53

3                                0.86                                3.48

2                                0.57                                3.50

1                                0.28                                3.57

40cm NICHROME

5                                0.64                                7.81

4                                0.51                                7.84

3                                0.38                                7.89

2                                0.27                                7.40

1                                0.13                                7.69

Analysis of preliminary

From the results of the preliminary experiment I can deduce that Constantan has the least varied results, and therefore the most reliable results, due to this I will use constantan rather than nichrome in my main experiment. According to ‘Science Data Book by R.M.Tennent’ constantan has a resistance of 8.29; we gained an average of 8.63, this was near, and so was another helpful point at which to base our nichrome/constantan decision on. We also saw the affects of leaving on the power supply whilst the results are being recorded, the wires did get very hot, very quickly, and so also needed changing for the main experiment.

Main experiment

Safety

Ensure that wires do not over heat.

Do not pull on the wires as they can cut through the skin.

Do not spill liquids on the equipment.

Plan

For the main experiment I will set up the apparatus in the same way to the preliminary (shown in diagram). I will use constantan for reasons previously explained. I will also, for a more accurate and reliable set of results, use five voltages for each length.

Set the required length, starting with the longest first so as to reduce the risk of over heating or burning out the wire and ruin the experiment.

...read more.

Conclusion

Evaluation

I am very pleased with the high level of accuracy of my results, especially for the 100cm length at which all resistances were the same. The points on my graph almost all lay on the line of best fit, which displays a high level of accuracy – which is helpful to draw a reliable conclusion, with no particularly anomalous results. For accuracy I used six different measurements, and didn’t have to repeat any of them. I took into account needing to allow the wire to cool, by turning off the power whilst taking readings, and keeping the cross sectional area constant. We maintained this using a 32 s.w.g. each time. Another factor to take into consideration was the angle at which the crocodile clips intercepted the constantan wire; we maintained this as a 90 degree angle, as it is the easiest to repeat. To investigate further into this experiment I could use different wires materials at different lengths and see if similar patterns and rules apply. If I was repeating this experiment altering one factor I think I would have used a wider range of wire lengths, to get a more accurate and detailed conclusion. I would also ensure that the crocodile clips have been connected to the wire at 90 degree angles each time, I think this was done, but it wasn’t something we regularly checked.

                                                    -Stefan Nagorski -

...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. Marked by a teacher

    Draw stress and strain graphs for the metal copper and the alloy constantan. Calculate ...

    4 star(s)

    Again this is due to it properties as an alloy, which makes it have a high young's modulus. The young's modulus is how stiff a material is. In metals the atoms are ionised and free electrons in between the ions.

  2. An experiment to find the resistivity of nichrome

    These results could be done better. 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.

  1. Discover the factors affecting resistance in a conductor.

    to a strong conclusion and supports my original prediction Therefore as the length of the carbon putty paper increases, the resistance increases, and this increases is directly proportional as no other factors affect these results. Also, one graph shoed that resistance was inversely proportional to area(diameter), as shown in a curve.

  2. Investigating The Effect Of Resistance On A Capacitor Circuit

    0 0.014 0.134 79 0 0 0 0.014 0.127 79.5 0 0 0 0.014 0.127 80 0 0 0 0.014 0.127 80.5 0 0 0 0.014 0.12 81 0 0 0 0.014 0.12 81.5 0 0 0 0.007 0.12 82 0 0 0

  1. Copper, Constantan, Manganan and Nichrome - which is the best conductor?

    I will do this by turning off the power pack when it isn't being used so heat doesn't build up in the wire. * I will also have to use the same ammeter and voltmeter during the whole investigation because different meters may give slightly different results.

  2. In our experiment we aimed to investigate the effect of the length of wire ...

    This allowed air to circulate, keeping it relatively cool. This was quite ineffective though. * We let the wire rest and cool between experiments for a minute or two. Prediction I predicted that if the length increases then the resistance will also increase in proportion to the length. I thought this because the longer the wire the more atoms

  1. Energy alternatives.

    Large land areas would also be needed to produce more energy, which will mean using artificial fertilisers. Burning large quantities of forest timber wood can have long term effects on the atmosphere and will lead to de-forestation. The principle behind biomass is releasing the energy stored in living plant materials,

  2. The aim of our investigations is to find out the ohmic limit so I ...

    Current (amps) Voltage (V) Resistance (?? Average Resistance (?? 50 0.2 2.6 13 13 50 0.2 2.6 13 13 50 0.2 2.6 13 13 50 0.2 2.6 13 13 50 0.2 2.6 13 13 Length of wire (cm) Current (amps) Voltage (V) Resistance (?? Average Resistance (?? 60 0.2 2.9 14.5 14.9 60 0.2 3.0 15 14.9 60 0.2

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