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What factors affect the Resistance of a Wire?

Extracts from this document...

Introduction

Richard Lai        Physics Sc1        29/05/2003

4th Form FI                MATH

Sc1- What factors affect the Resistance of a Wire?

In this experiment I am going to find out what factors and how they affect the resistance of a wire.

Prediction[a]

There are three given factors that can affect the resistance of a wire: length, cross-section area (abbrev CSA) and material. The two factors that I am going to work on are the length and the cross-section area.

1.) Length

My prediction of how the length can affect the resistance of a wire is the length is proportional to the resistance, i.e. if the length of a wire is doubled, then its resistance will also be doubled (see right). The equation that I referred to is this:

If the constant terms “ρ” and “A” are taken away, then we are left with “R” and “L”, which means that the resistance should be proportional to the cross-section area:

R∝L

Hopefully the results of this experiment will be the same as I have predicted.

2.) Cross Section Area

My prediction of how the CSA can affect the resistance of a wire is the resistance is inversely proportional to the CSA, i.e. the greater the CSA of the wire is, the lower the resistance is:

R1/a

The reason for this is because the thicker the wire, the more space there is for the current to travel through, and since the current finds it easier to travel through the thicker wire, the resistance would be lower. The diagram on the right is an example: if the wire is doubled in its radius, the resistance will be halved; therefore showing that the resistance of the wire is inversely proportional to the CSA.

Method

1.) Length

Middle

0.440Ω

0.680Ω

I have decided to use 0.14mm-radius wire for the length investigation, since it gives significant ranges of resistance, which can be shown clearly on a graph; for the CSA investigation, I have decided to use 80cm as the length for the wires. 90cm would be ideal, but I found it difficult to connect the copper wires together – they were simply not long enough. I want to make sure that the clips are clipped properly throughout the investigation, so I think 80cm would be a safer length, and yet still gives great ranges.

Results[b]

All my processed results are written down in 3 significant figures, so that they are all fair.

Length

Constant variables: same wire [radius (0.14mm), wire material (constantan)], current (0.5A)

 Length (cm) P.D. 1 (V) P.D. 2 (V) P.D. 3 (V) Aver. P.D. (V) Current (A) Resistance (Ω) 5 0.21 0.23 0.25 0.230 0.5 0.460 10 0.43 0.56 0.46 0.480 0.5 0.960 15 0.64 0.71 0.67 0.670 0.5 1.34 20 0.86 0.88 0.88 0.870 0.5 1.74 25 1.09 1.11 1.10 1.10 0.5 2.20 30 1.28 1.31 1.31 1.30 0.5 2.60 35 1.49 1.54 1.52 1.52 0.5 3.04 40 1.70 1.77 1.75 1.74 0.5 3.48 45 1.90 1.96 1.99 1.95 0.5 3.90 50 2.13 2.20 2.18 2.17 0.5 4.34

Length – measured with Ohmmeter

Constant variables: same wire [radius (0.14mm), wire material (constantan)]

Clips resistance: 0.2Ω

Conclusion

I can set up the same apparatus as the one I used for my experiment, but replacing the wire-board with a graphite. I will need graphite leads in different thicknesses for the “resistance against CSA” investigation, and, optional, graphite leads in different hardness’s for investigating the relationships between the hardness of the graphite lead and its resistance. I will need an insulator to hold the graphite lead up on the working surface so that there will be less risk of electric shock.

I will be using an ohmmeter to measure the resistance of the crocodile clips that I am going to use, so that its resistance can be excluded from the actual reading of the total resistance. Then I will do the same procedure as I did in the experiment for constantan wire, e.g. preliminary experiment to find out the sensible CSA for the “resistance vs. length” investigation and length for the “resistance vs. CSA” investigation, the number of readings, lengths, repeats, average, etc. I will bear in mind of what to be careful of, such as clearing the area around the apparatus, and not to leave the current on for too long.

I would guess that the graphite’s resistance would behave in the same way as the metallic wires do, but since this is something which I have never done before, I have no confidence that my prediction will be right, so in the future I might try and carry this investigation out.

[a]Planning: 5/8

[b]Obtaining Evidence: 8/8

[c]Analysing: 5/8

[d]Evaluating: 5/6

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Related GCSE Electricity and Magnetism essays

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

4 star(s)

* Keep metre stick stationary for every test, so to keep extension values fair for every test. * Do not alter the position of G-clamp, Pulley, metre rule, wooden blocks and table during all the experiments have been completed * Use all wire from same roll and the copper and constantan must be manufactured by the same company.

2. Investigation in resistance in wires

5 star(s)

To work out A I need to work out the radius of my wire length The diameter was 0.2mm 0.2/2 = Radius Radius = 0.1mm A = ?r� A = ? x 0.1� A = 3.14 x 10^-6 m� By plotting the average resistance against length on a line graph

1. Resistance of a Wire Investigation

1.16 0.50 2.32 60 1.22 0.44 2.77 70 1.25 0.38 3.29 80 1.27 0.35 3.63 90 1.31 0.29 4.52 100 1.33 0.29 4.59 Wire 1, Set 2: Length (cm) Voltage (V) Current (A) Resistance (W) (to 2 d.p.) 10 0.51 1.02 0.50 20 0.79 0.79 0.97 30 0.91 0.65 1.40

2. An in Investigation into the Resistance of a Wire.

and inversely proportional to the area of the cross section (if you double the cross sectional area, you halve the resistance). Ohm's law states that: V= I*R R=V/I I=V/R V= voltage applied in volts (V) I= current in amperes (A)

1. How does length and width affect resistance

Leave it on this length. 5. Wait for the values on both meters to stop on one value. When the values are constant record it. 6. do this with all the wires.-there are five 7. When you have done all the wires.

2. Discover the factors affecting resistance in a conductor.

The resistance of an ohmic conductor does not change when the voltage does: How this had lead me to a strong conclusion and supports my original prediction Therefore carbon putty is a linear conductor, and it obeyed Ohms Law, as it is not a diode, filament lamp or thermistor and its temperature remained constant throughout the experiment.

1. Find out how the length and width affect the resistance of a graphite track.

As a result the wire becomes warm. Because the electrons have got further to travel, the longer the carbon track the more atoms there will be. The electrons will bump into more atoms, (slowing them down) and creating more resistance and greater heating.

2. Resistance and Wires

These results support the claim that the results are very accurate. There is also a definite trend or pattern which the results follow. This also supports the fact that the data is accurate because it there are no stray results and each reading fits nicely into a pattern when drawn on the graph.

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The text provided is a student's lab report on an experiment to investigate the factors affecting the resistance of a wire. It contains background information, a hypothesis, method, results, and a conclusion. Here's my analysis:
no_question

the text does not contain any explicit mathematical questions or calculations. while it discusses the relationship between wire length, cross-sectional area, and resistance, it does not pose these as mathematical questions to be solved. the report is focused on describing the experimental method and results rather than presenting specific mathematical problems.

the content structure consists of:
1. an introduction explaining the purpose of the experiment
2. a hypothesis predicting how length and cross-sectional area will affect resistance
3. a detailed description of the experimental method
4. presentation and analysis of the results
5. a conclusion summarizing the findings and suggesting further investigations

while the report contains scientific reasoning and data analysis, it does not include any specific mathematical questions or provide answers to such questions. the mathematical relationships are discussed conceptually rather than presented as problems to be solved.
Given a text passage, determine:
    1. If it contains a mathematical question (including word problems or calculations)
    2. If an answer to that mathematical question is provided in the text

First, describe the content structure you found in 1-2 sentences.

Then provide your analysis in the following format:
TYPE: <one of the following values>
- NO_QUESTION
- SINGLE_QUESTION
- SINGLE_QUESTION_WITH_ANSWER
- MULTIPLE_QUESTIONS
- MULTIPLE_QUESTIONS_WITH_ANSWERS
system
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What factors affect the Resistance of a Wire?

Extracts from this document...

Introduction

Richard Lai        Physics Sc1        29/05/2003

4th Form FI                MATH

Sc1- What factors affect the Resistance of a Wire?

In this experiment I am going to find out what factors and how they affect the resistance of a wire.

Prediction[a]

There are three given factors that can affect the resistance of a wire: length, cross-section area (abbrev CSA) and material. The two factors that I am going to work on are the length and the cross-section area.

1.) Length

My prediction of how the length can affect the resistance of a wire is the length is proportional to the resistance, i.e. if the length of a wire is doubled, then its resistance will also be doubled (see right). The equation that I referred to is this:

If the constant terms “ρ” and “A” are taken away, then we are left with “R” and “L”, which means that the resistance should be proportional to the cross-section area:

R∝L

Hopefully the results of this experiment will be the same as I have predicted.

2.) Cross Section Area

My prediction of how the CSA can affect the resistance of a wire is the resistance is inversely proportional to the CSA, i.e. the greater the CSA of the wire is, the lower the resistance is:

R1/a

The reason for this is because the thicker the wire, the more space there is for the current to travel through, and since the current finds it easier to travel through the thicker wire, the resistance would be lower. The diagram on the right is an example: if the wire is doubled in its radius, the resistance will be halved; therefore showing that the resistance of the wire is inversely proportional to the CSA.

Method

1.) Length

Middle

0.440Ω

0.680Ω

I have decided to use 0.14mm-radius wire for the length investigation, since it gives significant ranges of resistance, which can be shown clearly on a graph; for the CSA investigation, I have decided to use 80cm as the length for the wires. 90cm would be ideal, but I found it difficult to connect the copper wires together – they were simply not long enough. I want to make sure that the clips are clipped properly throughout the investigation, so I think 80cm would be a safer length, and yet still gives great ranges.

Results[b]

All my processed results are written down in 3 significant figures, so that they are all fair.

Length

Constant variables: same wire [radius (0.14mm), wire material (constantan)], current (0.5A)

 Length (cm) P.D. 1 (V) P.D. 2 (V) P.D. 3 (V) Aver. P.D. (V) Current (A) Resistance (Ω) 5 0.21 0.23 0.25 0.230 0.5 0.460 10 0.43 0.56 0.46 0.480 0.5 0.960 15 0.64 0.71 0.67 0.670 0.5 1.34 20 0.86 0.88 0.88 0.870 0.5 1.74 25 1.09 1.11 1.10 1.10 0.5 2.20 30 1.28 1.31 1.31 1.30 0.5 2.60 35 1.49 1.54 1.52 1.52 0.5 3.04 40 1.70 1.77 1.75 1.74 0.5 3.48 45 1.90 1.96 1.99 1.95 0.5 3.90 50 2.13 2.20 2.18 2.17 0.5 4.34

Length – measured with Ohmmeter

Constant variables: same wire [radius (0.14mm), wire material (constantan)]

Clips resistance: 0.2Ω

Conclusion

I can set up the same apparatus as the one I used for my experiment, but replacing the wire-board with a graphite. I will need graphite leads in different thicknesses for the “resistance against CSA” investigation, and, optional, graphite leads in different hardness’s for investigating the relationships between the hardness of the graphite lead and its resistance. I will need an insulator to hold the graphite lead up on the working surface so that there will be less risk of electric shock.

I will be using an ohmmeter to measure the resistance of the crocodile clips that I am going to use, so that its resistance can be excluded from the actual reading of the total resistance. Then I will do the same procedure as I did in the experiment for constantan wire, e.g. preliminary experiment to find out the sensible CSA for the “resistance vs. length” investigation and length for the “resistance vs. CSA” investigation, the number of readings, lengths, repeats, average, etc. I will bear in mind of what to be careful of, such as clearing the area around the apparatus, and not to leave the current on for too long.

I would guess that the graphite’s resistance would behave in the same way as the metallic wires do, but since this is something which I have never done before, I have no confidence that my prediction will be right, so in the future I might try and carry this investigation out.

[a]Planning: 5/8

[b]Obtaining Evidence: 8/8

[c]Analysing: 5/8

[d]Evaluating: 5/6

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

Related GCSE Electricity and Magnetism essays

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

4 star(s)

* Keep metre stick stationary for every test, so to keep extension values fair for every test. * Do not alter the position of G-clamp, Pulley, metre rule, wooden blocks and table during all the experiments have been completed * Use all wire from same roll and the copper and constantan must be manufactured by the same company.

2. Investigation in resistance in wires

5 star(s)

To work out A I need to work out the radius of my wire length The diameter was 0.2mm 0.2/2 = Radius Radius = 0.1mm A = ?r� A = ? x 0.1� A = 3.14 x 10^-6 m� By plotting the average resistance against length on a line graph

1. Resistance of a Wire Investigation

1.16 0.50 2.32 60 1.22 0.44 2.77 70 1.25 0.38 3.29 80 1.27 0.35 3.63 90 1.31 0.29 4.52 100 1.33 0.29 4.59 Wire 1, Set 2: Length (cm) Voltage (V) Current (A) Resistance (W) (to 2 d.p.) 10 0.51 1.02 0.50 20 0.79 0.79 0.97 30 0.91 0.65 1.40

2. An in Investigation into the Resistance of a Wire.

and inversely proportional to the area of the cross section (if you double the cross sectional area, you halve the resistance). Ohm's law states that: V= I*R R=V/I I=V/R V= voltage applied in volts (V) I= current in amperes (A)

1. How does length and width affect resistance

Leave it on this length. 5. Wait for the values on both meters to stop on one value. When the values are constant record it. 6. do this with all the wires.-there are five 7. When you have done all the wires.

2. Discover the factors affecting resistance in a conductor.

The resistance of an ohmic conductor does not change when the voltage does: How this had lead me to a strong conclusion and supports my original prediction Therefore carbon putty is a linear conductor, and it obeyed Ohms Law, as it is not a diode, filament lamp or thermistor and its temperature remained constant throughout the experiment.

1. Find out how the length and width affect the resistance of a graphite track.

As a result the wire becomes warm. Because the electrons have got further to travel, the longer the carbon track the more atoms there will be. The electrons will bump into more atoms, (slowing them down) and creating more resistance and greater heating.

2. Resistance and Wires

These results support the claim that the results are very accurate. There is also a definite trend or pattern which the results follow. This also supports the fact that the data is accurate because it there are no stray results and each reading fits nicely into a pattern when drawn on the graph.

• Over 160,000 pieces
of student written work
• Annotated by
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user
The text provided is a student's lab report on an experiment to investigate the factors affecting the resistance of a wire. It contains background information, a hypothesis, method, results, and a conclusion. Here's my analysis:

TYPE: NO_QUESTION

The text does not contain any explicit mathematical questions or calculations. While it discusses the relationship between wire length, cross-sectional area, and resistance, it does not pose these as mathematical questions to be solved. The report is focused on describing the experimental method and results rather than presenting specific mathematical problems.

The content structure consists of:
1. An introduction explaining the purpose of the experiment
2. A hypothesis predicting how length and cross-sectional area will affect resistance
3. A detailed description of the experimental method
4. Presentation and analysis of the results
5. A conclusion summarizing the findings and suggesting further investigations

While the report contains scientific reasoning and data analysis, it does not include any specific mathematical questions or provide answers to such questions. The mathematical relationships are discussed conceptually rather than presented as problems to be solved.