• 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
  13. 13
    13
  14. 14
    14

Investigating Resistance in an electrical circuit

Extracts from this document...

Introduction

Investigating Resistance in an electrical circuit

Planning

The aim of this experiment is to investigate the resistance in an electrical circuit.  There are many different ways to investigate the resistance in a wire, however to do so there must be some background research and prior knowledge of electrical circuits and the components.

        Through research I have learnt that George Simon Ohm was one of the forefathers of research into electrical resistance. And, thus accordingly resistance is measured in ohms (Ώ). Resistance is the “opposition of a body or substance to current passing through it, resulting in a change of electrical energy into heat or another form of energy.” (www.dictionary.com)

        To calculate the resistance of a wire, you need to multiply together the current and voltage:

Resistance = Current x Voltage

R       =       I     x     V

image00.png

        The horizontal line is a divide sign. The calculation is started with whatever quantity that is looked for. "V=", "I=" or "R=" all possible formulae based on this particular Ohms law will be attained. Another useful method is if you place your finger on the calculation you are looking for you are left with the formula you are looking for, that is; V=IxR, I=V/R, R=V/I. It should be apparent that the formula works the other way to, that is; IxR=V, RxI=V, V/I=R and V/R=I. From this, we conclude that; Current equals Voltage divided by Resistance (I=V/R)

...read more.

Middle

80

0.72

0.28

2.57

75

0.67

0.29

2.31

70

0.72

0.3

2.16

65

0.67

0.31

2.03

60

0.65

0.33

1.95

55

0.63

0.35

1.74

50

0.64

0.38

1.64

45

0.61

0.39

1.31

40

0.62

0.43

1.17

35

0.51

0.46

0.93

30

0.5

0.55

0.73

25

0.43

0.64

0.54

20

0.4

0.69

0.41

15

0.35

0.7

0.31

10

0.28

0.84

0.21

5

0.22

0.97

0.04

For the graph with all 3 tabled results for constantan 26swg see attached sheet 1.

Results for Constantan 28swg

Table 1

Length (cm)

Voltage (Volts)

Current (Amps)

Resistance (Ohms)

100

1.75

0.39

4.49

95

1.73

0.38

4.55

90

1.66

0.4

4.15

85

1.65

0.42

3.93

80

1.63

0.44

3.7

75

1.6

0.46

3.48

70

1.56

0.48

3.25

65

1.5

0.5

3

60

1.44

0.52

2.77

55

1.4

0.55

2.55

50

1.34

0.58

2.31

45

1.27

0.61

2.09

40

1.2

0.65

1.85

35

1.14

0.68

1.68

30

1.04

0.74

1.41

25

0.95

0.8

1.19

20

0.82

0.86

0.95

15

0.66

0.93

0.71

10

0.54

1.06

0.51

5

0.36

1.22

0.3

Table 2

Length (cm)

Voltage (Volts)

Current (Amps)

Resistance (Ohms)

100

1.7

0.38

4.47

95

1.7

0.39

4.36

90

1.66

0.4

4.15

85

1.66

0.42

3.95

80

1.62

0.44

3.68

75

1.58

0.46

3.43

70

1.55

0.48

3.23

65

1.5

0.5

3

60

1.46

0.52

2.81

55

1.4

0.55

2.55

50

1.35

0.58

2.33

45

1.2

0.59

2.03

40

1.18

0.66

1.79

35

1.12

0.68

1.65

30

1.03

0.74

1.39

25

0.92

0.79

1.16

20

0.82

0.86

0.95

15

0.68

0.94

0.72

10

0.54

1.06

0.51

5

0.36

1.25

0.29

Table 3

Length (cm)

Voltage (Volts)

...read more.

Conclusion

Analysis of thickness

        In order to analyse the thickness of the wire I will first need to work out the area of the wire. I have got the thicknesses in British Standard Gauge and I have found a site (http://www.falcon-acoustics.co.uk/hintstipsgeneral.htm) which has a table with the thickness converted into millimetres. The conversions for the wires thickness’ are as follows:

Constantan 26swg = 0.457mm

Constantan 28swg = 0.376mm

Constantan 36swg = 0.193mm

        This however is the diameter of each of the wires; and the formula for the area of a circle is π x r². The radius of a circle is half the diameter. To work out the area of the wire I must first halve the diameter then square it then multiply by pie. Pie (π) is 22 ÷ 7 the number has definite end.

        Now I will work out the area for each of the wires.

Constantan 26swg:

0.457 ÷ 2 = 0.2285mm

0.2285² = 0.05221225mm

0.05221225 x π = 0.163946465 mm²

Constantan 28swg:

0.376 ÷ 2 = 0.188mm

0.188² = 0.035344mm

0.035344 x π = 0.11098016 mm²

Constantan 36swg:

0.193 ÷ 2 = 0.0965mm

0.0965² = 0.00931225mm

0.00931225 x π = 0.029240465 mm²

        This shows that the Constantan 26swg is thicker than the Constantan 28swg and the Constantan 36swg and by how much in mm².

“I also believe that the thicker the wire is the less resistance will be present.”

This is correct. I have taken the resistance from all 9 tables and put them in a graph (sheet4). I have taken the resistance from 50cm for all of them. The graph clearly shows the huge difference in resistance. As you can see the Constantan 36swg is more resistant than the 26swg and 28swg Constantan wire. The area of the Constantan

Evaluation

...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. Marked by a teacher

    Investigate young's modulus behind Constantan and Copper.

    4 star(s)

    The atoms in copper will just move easily and therefore will stretch apart causing the gap and slowly it will break as the bond will be pulled by the great load of weights which pulls the copper wire apart. The copper is therefore less ductile than the constantan material (alloy).

  2. Marked by a teacher

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

    4 star(s)

    The linear section however can be used to calculate the Young's modulus of the material, by stress/strain. Figure 2 As I mentioned earlier that I believe the young's modulus of constantan will be higher than copper, this is because it is an alloy.

  1. Free essay

    How the length of constantan wire affects the ressistance in a electrical circuit

    However if the wire gradually get hot this increases the movement inside the wire, causing more collision and it is likely the conductor will have a high resistance. Lastly different materials can also have numerous affects to the resistance, some wires are good conductors some are bad conductors.

  2. Resistance and Wires

    calculate this data is the diameter of the wire, which was measured 3 times each for precision and accuracy. Calculations were the only other means of manipulating that data to give these results. Pi was multiplied by the radius (half of the diameter)

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

    Using these results, I will now attempt to plot several graphs and then I will come up with conclusions in line with scientific knowledge. These conclusions should therefore enable me to theorize a general rule of some sort that I can in turn test in an extension experiment.

  2. Investigating The Effect Of Resistance On A Capacitor Circuit

    Time (s) 47�F 100�F 470�F 1000�F 2200�F 0 3.576 3.576 3.576 3.576 3.576 0.5 3.583 3.569 3.576 3.576 3.583 1 3.583 3.569 3.576 3.576 3.583 1.5 2.947 2.629 3.576 3.576 3.576 2 1.23 1.406 3.576 3.576 3.491 2.5 0.516 0.919 3.576 3.364 3.413 3 0.226 0.608 3.576 3.18 3.349 3.5 0.099 0.403

  1. Copper, Constantan, Manganan and Nichrome - which is the best conductor?

    Constantan, which is also an alloy contains 60% copper and 40% nickel. This has less copper again therefore constanan will be a worse conductor than both pure copper and manganin. Nichrome contains 20% chromium and 80% nickel. It has no copper in it so it will be the worst conductor of them all.

  2. Planning Experimental Procedures

    If I did have three resistance calculations then I could have plotted three crosses and looked at how far apart each set was. If a set was close together then I would know that I am accurate, but if the range of the plots were far apart then I know that I have collected appalling results!

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