• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10

Investigating How The Length Of A Wire Affects Its Resistance.

Extracts from this document...


Coursework        Physics GCSE        July 2003

Investigating How The Length Of A Wire Affects Its Resistance


I predict that as the length of a wire increases, the resistance too will increase. This is because the resistance is directly proportional to the length, meaning that as the length of a wire increases by a constant (k), the resistance too will increase by the same constant (k). For example, the length of the wire was 2 centimetres, and the resistance of the wire was 5 centimetres. If the length is now 4 centimetres, the resistance of the wire will be 10 centimetres, because 2 is the constant, and when the length is multiplied by the constant, so is the resistance. This can also be shown as r α l, or        r = kl, k being the constant. Because the length of the wire is directly proportional to the resistance, I predict that the graph will look like the Graph shown below:

Resistance of wireimage00.pngimage01.png


Graph goes

through origin

(0,0)                                                Length of wire


Because the length of the wire is directly proportional to the resistance, I predict that the graph will go through the origin (0,0), and will go up in a straight line. In addition to this, the gradient of the graph (change in y/change in x)  will equal the constant, i.e. in the equation R=kl, the gradient will b k.

Scientific Theory:

Metals are very good conductors due to their structural arrangement, which consists of ions and elections; each ion surrounded bout numerous electrons. When a current passes through a metal the ions appear to be in fixed positions and held together, but in reality vibrate, whilst the electrons are moving.

...read more.



















I chose a thin wire because the more thick that the wire is, the more collisions occur and therefore an increase in resistance as a result of the circuit heating up too quickly.

We additionally decided to use constantan wire instead of copper wire as the constantan wire heated up less, because of a lower current passing through it, and therefore a lower number of collisions. This was ideal because we wanted the temperature to remain constant, as explained in the ‘scientific theory’ section.  

Deciding the type of wire

Type of wire

Voltage (volts)

Current (amps)

Resistance (ohms)


(30cm, thin)











(30cm, thin)










The number of repeats for each individual measurement of resistance over a range of answers was decided to be as high as possible without being to time consuming.  In the end we decided to use 3 repeats per each individual measurement, because it was just about enough to avoid anonymous results and to get accurate results.

Digital voltmeters and ammeters was the decision I made regarding apparatus. This was because multimeters required continuous changes and we tended to receive over -  high results. Similarly, analogue ammeters and voltmeters proved to be difficult to read off (because of fluttering results) and inaccurate.



Prepare apparatus for experiment, including digital ammeters and voltmeters, one cell, a thin constantan wire, crocodile clips (to secure the wire), sticky tape(to hold down the wire so it can be stretched from one end of the metre ruler to the other so that the wire is straight and ‘kinks’ are not present) and a meter ruler(with measurements of centimetres and millimetres, so that the results are recorded accurately).

...read more.


Additionally if I chose a different metal, for example copper, then I would have obtained different results because each metal has a different ionic arrangement; and the number of ions and electrons affects the temperature and therefore the collisions, resulting in a change in resistance. Furthermore, I could have chosen to do the experiment with a non – metal, so see what kind of results I would obtain then.

As we go across the periodic table there are more electrons, therefore meaning that each of the metals are denser, because the nucleuses get larger. Therefore the metals would have a high atomic number, and resistance would become higher, because if the electrons and ions were larger there is more chance of collisions and the collisions become larger.

Ravi Dewji 10S

...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)

    For this graph a curve will be needed for both sets of data to show how stress changes with strain and to see the yield point graphically. It will be accurate as the points will be plotted carefully with due care to ensure an accurate graph and the scale will be relevant as to show the best possible curve.

  2. Resistance of a Wire Investigation

    The only problem of this experiment is that there is no way to define or "measure" the colour of light. Wavelength would be a solution but this cannot be measured with available equipment. We only have a general idea of how to class colours.

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

    If the experiment is finished during a different time, conditions will have change, which could result in some independent variable factors that have not been considered, changing. This could adversely affect the reliability of my experiment The resistance will be measured using a combination of an Ammeter and a Voltmeter.

  2. How length affects resistance in a wire

    My first test I decided to keep the current at 1.26 Amps. Immediately I could see that this would not be the most reliable choice for a good set of results. This is because at 1.26 Amps the voltage was moving around all over the place and we weren't getting consistent results.

  1. Physics coursework- Investigating the resistance of a wire.

    It is shown in the diagram: * Write out the results table. * Set power to 6v. * Record thickness of the wire. * Turn the power pack on. * Attach the crocodile clip to the wire at every 10 cm and measure the voltage and current for each.

  2. 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.

  1. Free essay

    Aim: the aim for this experiment is to check if the length of a ...

    * Turn off the power pack each time before moving on to the next reading. * Make sure the thickness of the wire is the same through out the whole length as it can affect the resistance of a wire.

  2. Free essay

    How the length of constantan wire affects the ressistance in a electrical circuit

    when the particles and the reactant meet they connect causing a collison this happens more frequently if the rate of reaction increases. I am going to calculate the resistance of constantan wire in which I will Resistance is can be calculated by using R= V/I where R is resistance, V is voltage and I is current.

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