• 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
11. 11
11
12. 12
12

# Investigation of the factors that affect the resistance of a wire.

Extracts from this document...

Introduction

Investigation of the factors that affect the resistance of a wire

AIM: To investigate how the length, the cross sectional area and the material of a wire affect its resistance.

PLANNING:

Background information

Metals have a high density of conduction electrons. The aluminium atom for example has three valence electrons in a partially filled outer shell. In metallic aluminium the three valence electrons per atom become conduction electrons. The number of conduction electrons is constant, depending on neither temperature nor impurities. Metals conduct electricity at all temperatures, but for most metals the conductivity is best at low temperatures.

Resistance in electricity is the property of an electric circuit or part of a circuit to transform electric energy into heat energy by opposing electric current. Resistance involves collisions of the current-carrying charged particles with fixed particles that make up the structure of the conductors; this can be seen in the diagram below. Resistance is often considered as localized in such devices as lamps, heaters, and resistors, in which it predominates, although it is characteristic of every part of a circuit, including connecting wires and electric transmission lines.

## Diagram 1: The collisions of electrons with ions in a circuit

Electron

Ion

direction

in which the electron

is moving

Here the electron is going to collide with the ion and so the speed at which it is traveling will decrease and since the electron is one of the current-carrying charged            particles the current in the circuit will decrease.

The spread of electric energy in the form of heat, even though small, affects the amount of electromotive force, or driving voltage, required in order to produce a given current through the circuit. In fact, the electromotive force V (measured in volts) across a circuit divided by the current I (amperes)

Middle

5.32

0.6 meter

0.74

0.20

3.7

1.04

0.26

4.00

1.23

0.32

3.84

1.42

0.41

3.46

1.63

0.45

3.62

1.80

0.48

3.75

3.73

0.4 meter

0.46

0.18

2.56

1.08

0.47

2.30

1.26

0.53

2.38

1.45

0.59

2.46

1.56

0.61

2.56

1.71

0.67

2.55

2.47

0.2 meter

0.59

0.44

1.34

0.94

0.70

1.34

1.11

0.82

1.35

1.36

1.01

1.35

1.58

1.17

1.35

1.81

1.34

1.35

1.35

Results obtained for the manganin wire:

 Lengths of the wire used. V I R V I R V I R V I R V I R V I R Average resistances found from other resistances. 1.0 meter 0.89 0.16 5.56 0.98 0.18 5.44 1.06 0.20 5.30 1.24 0.23 5.39 1.45 0.27 5.37 1.61 0.30 5.37 5.41 0.8 meter 0.87 0.20 4.35 0.99 0.22 4.50 1.06 0.24 4.42 1.24 0.27 4.59 1.45 0.32 4.53 1.61 0.39 4.13 4.42 0.6 meter 0.86 0.26 3.31 0.99 0.30 3.30 1.07 0.32 3.34 1.25 0.38 3.29 1.46 0.44 3.32 1.62 0.49 3.31 3.31 0.4 meter 0.86 0.35 2.46 0.98 0.40 2.45 1.07 0.43 2.49 1.26 0.50 2.52 1.44 0.62 2.32 1.65 0.70 2.36 2.43 0.2 meter 0.88 0.77 1.14 0.98 0.86 1.14 1.05 0.91 1.15 1.25 1.09 1.15 0.24 0.21 1.14 0.37 0.32 1.16 1.15

Results obtained for the copper wire:

 Lengths of the wire used. V I R V I R V I R V I R V I R V I R Average resistances found from other resistances. 1.0 meter 0.16 0.18 0.89 0.18 0.24 0.75 0.17 0.30 0.57 0.68 1.20 0.57 0.17 0.50 0.34 0.11 0.18 0.61 0.62 0.8 meter 0.12 0.20 0.60 0.14 0.26 0.54 0.15 0.31 0.48 0.22 0.51 0.43 0.13 0.40 0.33 0.19 0.61 0.31 0.45 0.6 meter 0.10 0.17 0.59 0.06 0.23 0.26 0.07 0.26 0.27 0.70 0.30 0.38 0.17 0.52 0.33 0.28 0.96 0.29 0.35 0.4 meter 0.04 0.18 0.22 0.05 0.25 0.20 0.09 0.35 0.26 0.15 0.40 0.38 0.09 0.41 0.22 0.16 0.65 0.25 0.26 0.2 meter 0.04 0.18 0.22 0.11 0.94 0.12 0.07 0.31 0.23 0.13 0.46 0.28 0.08 0.39 0.21 0.12 0.54 0.22 0.21

Results obtained for the nichrome wire:

Conclusion

During this write up I calculated the resistivities of the metals that I used, I looked in an A-level physics book for the values it gave for the resistivities of those metals in order to compare them with the values I found. The following are the resistivity values that I found in the book:

• The resistivity for constantan is 49 * 10-8
• The resistivity for manganin is 44 * 10-8
• The resistivity for copper is 1.7 * 10-8
• The resistivity for nichrome is 110 * 10-8

It can be seen that my resistivity values calculated in the ANALYSIS SECTION are very close to those found in the book. This further emphasises my opinion that my results are accurate enough to draw conclusions.

Further Work

To improve the experiment in order to provide additional and more reliable evidence for a conclusion I would carry out the experiment using additional different metals to see how their resistances would change as their lengths and cross sectional areas were varied. Such examples of these metals could be for example titanium, silver, steel, brass etc…

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. ## To investigate how the resistance, R, of a length of wire, l, changes with ...

4 star(s)

when it should), which can be possible on the analogue instruments such as the ammeter. If the zero error happens, then I will adjust the instrument to read zero or the inaccurate zero reading should be taken and should be added or subtracted from any other reading taken.

2. ## Resistance Aim: my main aim is to investigate the factors that affect the resistance ...

3 star(s)

With this previous information of this material it will help making an accurate hypothesis and it should also be clear when problems occur. Wires of different lengths will have to be tested to prove that resistance is in proportion to length.

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

a very large resistance especially since some are better conductors of energy I predict that the constantan wire will have more resistance than copper because it is not a very good conductor, whereas, copper is an excellent conductor so it will have a low resistance because electricity can pass through it pretty easily without any obstacles.

2. ## Discover the factors affecting resistance in a conductor.

time, so that temperature affected the results as the circuit was heated * One of my results was not recorded using the correct voltage output from the power unit, so there was a different average * One of the wires was not connected properly to a certain item of apparatus

1. ## Electromagnets - What factors affect strength of an electromagnet?

The anomaly may also have been resulted, because the iron bar might have sided out slightly, causing the magnetic field to weaken. During both of the experiment I also observed number of things. During the first experiment I noticed that, when the power pack was switched off on a particularly

2. ## Investigate how the cross section of a wire affects the resistance in a circuit.

SWG Conversion graph- To convert the SWG into inches to find out the area Wire Cutter- To cut the wire to the right size. We need the voltmeter and the ammeter to work out the resistance in the wire, using the formula - R = V I 24 SWG 26

1. ## Resistance of a Wire Investigation

of the material , so if there is a larger number of atoms there will be a larger number of collisions which will increase the resistance of the wire. If a length of a wire contains a certain number of atoms when that length is increased the number of atoms will also increase.

2. ## Resistance and Wires

As shown in the table, the results do tend to increase. This should not be the case if the two variables are in direct proportion to each other. This increase in the value of 'n', can however be explained. My explanation for this is similar to the reason for the

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