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For my coursework I am going to investigate "Ohms Law".

Extracts from this document...

Introduction

Ciarán McMullan 12c

Introduction

For my coursework I am going to investigate “Ohms Law”. This states that the current flowing through a wire is proportional to the potential difference across it. I am going to test resistance through a wire from 0-80 centimetres at 10cm interval changing the voltage from 1.5 to 3 to 4.5 volts therefore repeating three times at each interval for reliability.

Safety

There are some rules and precautions to ensure safety while performing the experiment. We must:

  • Tuck in our stools, tuck in our ties and stand during the experiment.
  • Wear safety glasses.
  • Not run.
  • Not mess about.
  • Listen carefully to all instructions.
  • Take our time.
  • Not touch the nichrone wire.

Hypothesis

I think that the amount of current flowing through the wire will be directly proportional to the length of the wire. As the length increases so will the resistance proportionally.

Apparatus

I will need the following things for this experiment:

A voltmeter, ammeter, battery power supply, key, stick with nichrone wire, metre stick and leads.

image00.pngimage01.png

Method

  • Set up your apparatus according to diagram one after following the safety precautions.
  • Place the key 10cm up the wire.
  • Record readings onto table from ammeter and voltmeter. Resistance = V/I
  • Do this 3 times, each with a different voltage – 1.5, 3 and 4.5volts.
  • Repeat at 20, 30, 40, 50, 60, 70 and 80cm.
  • Find the resistances and average resistance and record these in a table.
...read more.

Middle

Results

Here is a table of my results.

Length Of Wire

Current

Resistance

Voltage

Av. Resistance

1

2

3

1

2

3

1

2

3

...read more.

Conclusion

2.95

3.83

2.713

50cm

0.41

0.82

1.38

3.51

3.69

3.2

1.44

3.02

4.42

3.5

60cm

0.35

0.68

1.07

4.22

4.16

4.1

1.48

2.83

4.39

4.16

70cm

0.3

0.63

0.96

4.76

4.68

4.64

1.43

2.95

4.46

4.693

80cm

0.28

0.53

0.86

5.32

5.29

5.42

1.49

3.02

4.5

5.343

Here is a graph of my results.

image04.png

This graph shows a positive correlation between the two axis.

Conclusion

My conclusion is that the longer the wire is, then the higher the average resistance will be and we can see this in both the table and graph.

Conclusion

...read more.

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