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

Investigating Resistance in Wires

Extracts from this document...

Introduction

Investigating Resistance in Wires

Plan

Aim

Our aim was to investigate the resistance of a piece of wire, and to try and find the relationship between the length of a section of wire and it’s resistance. To do this, we are planning to use a one-metre length of wire and measure off the different sections. We will take values for the amperage and voltage of each length, repeating each experiment twice to ensure accuracy. The major problem we are likely to come across is the wire heating up, as this will cause inaccuracy in the readings.

        The equipment will be set up as below,

Measurements

We decided to take values of voltage and amperage, then use Ohm’s Law to find the resistance value. We will take readings at 10cm intervals between 30cm and 100cm, giving us a total of eight values. We chose to start at 30cm rather than 10cm as starting at 10cm would be too short a distance for the electricity to travel through causing over-heating of the wire leading to inaccuracy of results.

...read more.

Middle

                   5.20

                   0.17

                 30.59

                 90.00

                   5.06

                   0.14

                 36.14

               100.00

                   5.13

                   0.12

                 42.75

image00.png

The first time we did the investigation, we got a very unreliable set of results, after investigating the cause, we deducted we had a faulty battery pack, so decided to re-do investigation, this time our results were a lot more reliable, but to ensure accuracy, we repeated each length twice

Length

...read more.

Conclusion

  • We assume the cross-section of the wire is constant throughout the length, i.e. a constant diameter.

    1mm diameter                                    0.950mm diameter

 1 x 3.142 = 3.142 mm²                        0.950 x 3.142 = 2.985 mm²

This change in diameter will cause a funnel effect, restricting the progress of the free electrons between the atoms, This would provide inaccurate results, leading to a false impression. If this fault occurs at the start of the wire it will affect all the results, if it occurs towards the end, it would change the pattern of results, causing incorrect placement of the line of best fit.

Improving the accuracy

The accuracy of this test can be improved in many ways:

  • The use of a Jockey (thin blade contact) to increase accuracy when measuring the sections of wire, guaranteeing accurate lengths.
  • Higher specification (more accurate) Ammeter and voltmeter.
  • Increase increment value i.e. 100cm. steps instead of 10cm, broadening  the range of results leading to a more accurate graph.
  • Add one large distance to confirm analysis of linear relationship (see analysis for extrapolated result)
  • The use of a constant power supply as the batteries will drain during the test, falsifying the results.
  • Ensure wire is of a constant cross-section (see above).

...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. Peer reviewed

    Investigation in resistance in wires

    5 star(s)

    Although all of these differences I believe the accuracy of my test was very good, I was a mere 0.00000014 ? away from what the laboratory tests calculated the resistivity to be. From my resistivity graph I can see that all of the points for average resistance are very close

  2. Investigate the resistance of different wires and how at different lengths the voltage increases ...

    * We used a variable resistor to keep the amps at 0.3 * The width of wire was always 24 SWG And I couldn't control the temperature but from the above you can see that my variables were controlled quite well.

  1. Resistance and Wires

    being the dependent variable. The results from the graph indicate a steady increase in resistance as the length of wire increases, shows by the positive correlation of the graph. The relationship between the length and resistance of the wires is shown by the graph to be a proportional relationship.

  2. Physics Coursework Investigating Resistance of wires and its relationship to length.

    I set up my circuit and tested Nichrome, Constantin and Copper. I didn't test Tin because the school did not have any available. Nichrome: Length (mm) Current (i) Voltage (v) 500 0.65 3.09 600 0.52 3.06 700 0.48 3.32 800 0.45 3.33 These are good results, that would be good to put on a graph and show a clear correlation.

  1. Resistance of wires

    is proportional to the length of wire; so we decided to keep increasing the length of wire by 50cm. I will reach up to 3m so that a sensible amount of results can be plotted on the graph. And so I went on to do my final experiment.

  2. Resistance of Wires

    Electrons have to pass through this doubled distance of lattice structure, and the probability that the electrons will collide with the metal ions will increase, so resistance also doubles. Due to the fact that there is more lattice as the length of the wire increases, electrons find that they have

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