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

Investigating How The Length Of A Wire Affects Its Resistance.

Extracts from this document...

Introduction

Coursework        Physics GCSE        July 2003

Investigating How The Length Of A Wire Affects Its Resistance

Prediction:

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

        (ohms)

Graph goes

through origin

(0,0)                                                Length of wire

                                                       (cms)

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.

Middle

2.72

1.68

1.68

1.68

1.61

1.62

1.64

Thin

3.14

3.15

3.14

0.58

0.59

0.58

5.41

5.34

5.41

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)

Constantan

(30cm, thin)

3.14

3.14

3.15

0.58

0.59

0.59

5.41

5.32

5.34

Copper

(30cm, thin)

0.39

0.38

0.38

1.30

1.29

1.32

0.30

0.29

0.29

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.

Procedure

Method

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.

Conclusion

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)

    Hence we can deduce from the information that constantan can handle more stress than copper even though the wire diameter of constantan was 0.002m smaller and that the constantan wire is able to extend more than copper when equal and grater forces are applied to it.

  2. Marked by a teacher

    Investigating how the length of wire affects its resistance

    3 star(s)

    In terms of my data collected, looking at my graph, there is an anomaly. I can see this as tall the points are very close to the trend line except for one. When the length of wire was at 50cm, the point is far off the trend line I drew than any of the other points.

  1. Free essay

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

    This is because the increased resistance reduces the amount of current flowing in the circuit. The greater the resistance the greater the electrical push needed. I decided to do the experiment seven times this is because I wanted a good average result.

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

    Only 3 would allow this as one would be completely different against two that were similar. The anomalous result can then be repeated. Repeats will make the results more reliable (See the accuracy part of the investigation for more information)

  1. Resistance of a Wire Investigation

    the pondweed using the plaster sine. Place a water-filled test tube upside down and over the funnel (see diagram). Place the ruler so that the "0" measurement is aligned with the side of the beaker. (Distance measured from side of beaker to edge of light bulb)

  2. How length affects resistance in a wire

    diagram showing what my actual circuit diagram will look like which I am testing in preliminary: This is a diagram of the circuit that I will use in my experiment. During preliminary I will test if it all works well and if it does I will use this circuit for my real experiment.

  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

    The reason I have chosen to measure voltage instead of current is because voltage is a measure of the energy carried by the charge and current is the rate of flow of the charge. As I want to investigate how much electricity is being produced I will measure the voltage.

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