• 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

Investigating How The Resistance Of A Wire Changes With Length

Extracts from this document...

Introduction

Neha Shah – 10EC/10PY

Investigating How The Resistance Of A Wire Changes With Length

AIM

To investigate the relationship between the length of wire and its resistance when a voltage is applied.

PREDICTION

If I double the length of a wire I would expect the resistance to approximately double proportionally. If I halve the length of the wire I would expect the resistance to approximately halve proportionally. I predict that as the wire gets hotter, its resistance will increase.

HYPOTHESIS

The wire allows an electric current to flow through it, but it does not allow the current to flow with ideal freedom. Electric current is the flow of electrons. This is a diagram showing atoms in the metal (which are really positive ions) surrounded by a sea of free electrons.

Collisions between the free electrons and positive ions of the conductor (wire) interfere with the flow of electrons from the current. In a collision the electrons collide with the ions in the wire and as a result they lose kinetic energy which is transformed into heat. This prevents the flow of electrons and this effect is known as resistance. The resistance of a length of wire is calculated by measuring the current present in the circuit (in series) and the voltage across the wire (in parallel). These measurements are then applied to this formula:

                             Voltage                                 

               Current

The symbol for ohms is the Greek letter omega, Ω.

...read more.

Middle

0.68

0.84

5.55

5.88

6.00

5.88

5.95

5.85

90cms

1

2

3

4

5

0.18

0.38

0.56

0.76

0.92

5.55

5.26

5.36

5.26

5.43

5.37

80cms

1

2

3

4

5

0.22

0.42

0.62

0.82

1.02

4.54

4.76

4.83

4.88

4.90

4.78

70cms

1

2

3

4

5

0.24

0.48

0.72

0.96

1.06

4.17

4.17

4.17

4.17

4.72

4.28

60cms

1

2

3

4

5

0.30

0.68

0.82

1.02

1.12

3.33

3.45

3.65

3.92

4.40

3.75

50cms

1

2

3

4

5

0.36

0.68

1.00

1.08

1.16

2.77

2.94

3.00

3.70

4.31

3.34

40cms

1

2

3

4

5

0.42

0.84

1.22

1.98

2.20

2.38

2.38

2.45

2.65

2.79

2.53

30cms

1

2

3

4

5

0.52

1.10

1.70

2.20

2.80

1.92

1.81

1.83

1.86

1.88

1.86

20cms

1

2

3

4

5

0.90

1.62

2.25

3.22

4.02

1.11

1.23

1.33

1.42

1.43

1.30

Constantan 0.25mm

LENGTH (cm)

VOLTAGE (V)

CURRENT (A)

RESISTANCE (Ω)

...read more.

Conclusion

I think that investigation was carried out fairly and safely. We managed to keep everything the same apart from the length of the wire and voltage. We did not change the wire therefore the cross-sectional area and material of the wire remained the same. But because we used the same wire the voltage applied slowly heated up the wire without me knowing towards the end of the experiment affecting our results and giving me a few anomalous results even though we kept the voltage setting low. We could have overcome this problem by changing the wire but taking it from the same reel of wire. This way the temperature of the wire remains constant and also the cross-sectional area and material remains constant.

If I was to do this investigation again to get more reliable data I woulduse pointers instead of the crocodile clips which I used. This is because pointers are a lot more accurate, because they have a smaller surface area on their tips than crocodile clips. This in effect would give much more accurate measurements. I would also use a digital voltmeter, to get a more accurate readings of the volts.

...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. Resistance of a Wire Investigation

    These would show up on my graph. However, there seemed to be few anomalies than was expected when the experiment was being performed. Almost all readings were in correlation with each other and all of the anomalies were in the high photosynthetic rate end of the results.

  2. Discover the factors affecting resistance in a conductor.

    We can conclude that they are inversely proportional. Therefore a graph of resistance against 1/area would be directly proportional. As shown. Therefore, as the graph is a straight line of best fit through the origin, as the length of the carbon putty paper increases, so does the resistance, and this increase shows variables that are directly proportional to each other.

  1. To Investigate the Relationship between the Resistance and the Length of a Wire

    Current and Voltage Measurements for 26swg (0.44mm) Nichrome of Length: 30.0cm, and Error Calculations Current, A I % error Voltage, V V % error Resistance, ? R % error R abs. error 0.09 � 0.01 11% 0.22 � 0.01 5% 2.20 2.20 � 16% 2.20 � 0.35 0.10 � 0.01

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

    By then, I should have 15 different sets of results for the resistance while changing length. 1.5.4. CROSS-SECTONAL AREA This can be described as the width of the wire, but scientifically is the cross-sectional area of the wire in mm2.

  1. To investigate how the resistance of a wire changes in relationship to its length.

    The resistance of a wire increases with length and temperature; it decreases as the cross sectional area is increased. It also depends on the substance. Resistance, Current and Voltage are all directionally proportional to each other: The HIGHER the VOLTAGE the HIGHER the CURRENT The HIGHER the RESISTANCE the LOWER

  2. To find out how the resistance changes as the length of the wire changes.

    We have kept to having one type of wire - Constantan. This is because it has a higher resistance than nichrome and it isn't affected by heat on the outside whereas nichrome is. I have chosen to have a higher range because there won't be much resistance to measure as if the length decreases so does the resistance.

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