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

How does the diameter or cross-sectional area of a wire affect its resistance?

Extracts from this document...

Introduction

Physics

How does the diameter or cross-sectional area of a wire affect its resistance?

Aim:

I am going to investigate how the diameter, or gauge, of a wire affects its resistance. In order for me to do this, I will need to find as many different diameters of wire as I can. I will cut each one to a reasonable length (probably about 10cm), then connect it to a battery pack and measure the current and voltage (with an ammeter and voltmeter respectively). From these readings I will calculate the resistance, using the formula:

R = V / I                           (Resistance = Voltage / Current)

The scale by which the diameter of wires is measured is called SWG (standard wire gauge) which confusingly goes up as the wire gets thinner. However I shall not use this in my graphs, as I do not know enough about SWG to make any worthwhile observations. The gauge of wires can also be measured by their cross-sectional area.

Scientific Theory:

Some factors affecting the resistance of a wire are:

  • its temperature
  • the metal it is made from
  • its diameter/cross-sectional area
  • its length

...read more.

Middle

Run 1

Run 2

SWG

Diameter

Voltage (V)

Amps (A)

Resistance R=V/I

Voltage (V)

Amps (A)

Resistance R=V/A

20

0.9

0.25

1.6

0.15625

0.25

1.6

0.15625

22

0.71

0.16

1

0.16

0.175

1.5

0.11666667

24

0.56

0.6

1.45

0.4137931

0.6

1.4

0.42857143

26

0.45

0.8

1.25

0.64

0.8

1.25

0.64

28

0.4

0.9

1.2

0.75

0.9

1.2

0.75

30

0.31

1.1

1

1.1

1.1

1

1.1

32

0.28

1.2

0.95

1.2631579

1.2

1

1.2

Run 3

Average

SWG

Diameter

Voltage (V)

Amps (A)

Resistance R=V/A

...read more.

Conclusion

x-axis and Resistance (Ω, or Ohms) on the y-axis. It showed a negative correlation, but had this weird thing going on at the end – an anomaly. I was able to draw quite a clear curve of best fit. The graph proved my theory correct, because as the diameter increased so the resistance of the wire decreased.

Evaluation:

        I believe the experiment was a success, as it proved my theory correct and my graph showed a clear curve of best fit. However there was an anomalous reading, right at the end. This may have been a mistake in reading the meters, or a mistake in calculating the resistance.

        To improve the accuracy and fairness of my experiment, I could have done the following things:

  • used a more reliable power source (the power flow from battery packs weakens with use),
  • cleaned the connections within the battery pack (corroded or dirty connections can affect power flow),
  • used more accurate am- and volt- meters (i.e. with a greater number of decimal places),
  • widen my range of results by connecting the circuit to more than one cell of the battery pack,
  • cut more lengths of wire from different rolls (one roll alone may not be representative of that particular gauge) as defects etc. may affect the results.

...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. Strain Gauge

    Method: Firstly I set up the equipment as shown below in my diagram. I have placed three resistors in my experiment to see if a differential voltage will be present across the wire. The three 123ohm resistors connected across the circuit as shown below.

  2. How the Resistance of a Wire is affected by Cross-Sectional Area

    Because the wider the wire is the easier it is for the electrons to pass, and the narrower the more difficult it is for the electrons to pass. This agrees with my prediction because in my prediction I stated that if the cross-sectional area of the wire decreases then the resistance will increase in proportion to the cross-sectional area.

  1. To investigate how the length (mm) and the cross-sectional (mm2) area of a wire ...

    I will also have to make sure that I wear rubber soled shoes since the quickest way for electricity to flow through to the earth is through me, so if I wear rubber soled shoes, the electricity cannot pass through me.

  2. Resistance and Wires

    To improve the reliability of the experiment, I could have taken more readings of the recordings of each length of wire. This would have meant that I could have calculated a more accurate mean and hade a more detailed range bar.

  1. Investigate how mass affects the diameter of an impact crater.

    These will need to be kept constant throughout the experiment in order to ensure a fair test as any unexpected alterations during the experiment may affect the accuracy of my results. BACKGROUND KNOWLEDGE: For a collision to occur, the colliding object would need to contain energy.

  2. How does the length and cross-sectional area of a wire affect resistance

    As you can see from the 1st diagram there is less collisions. When the length of the wire is increased then the resistance will also increase as the electrons will have a longer distance to travel and so more collisions will occur.

  1. Investigate how mass affects the diameter of an impact crater.

    The first exclusion is the angel of impact. This is primarily due to the reason that it would be too difficult to setup and furthermore beyond measure. The second is evenly between air resistance and gravity. This is logically due to the reason that amongst the apparatus I am provided with to conduct the experiment, these factors will be immeasurable.

  2. The aim of this investigation is to find out the cross-sectional area of a ...

    The material will not change at all and to make sure I will check with the teacher to make sure that all of the wires are the same. The temperature in the room will remain the same and there is not much chance of it changing only due to extreme circumstances.

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