• 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

Investigate how the length of a wire affects the wires resistance.

Extracts from this document...

Introduction

        -  -        Daniel Sheedy 5S1 5JR

GCSE Physics Coursework: Skill P

Factors Affecting the Resistance of a Wire

Aim

The aim of this experiment is to investigate how the length of a wire affects the wires resistance.

Background Information

Some variables that affect the resistance in a wire are:

  • Length of the wire
  • Thickness of the wire
  • Temperature of the wire
  • Voltage running through the wire
  • Material of the wire


Of these variables, I will be investigating the length of the wire and how it affects the resistance. The other variables are going to be kept constant in the experiment to make sure that only length, of the wire is investigated and to make it a fair test.  

The resistance (R) is measure in ohms (Ω), and is calculated by dividing the voltage (V) by the current (I):

V / I = R

Ohm’s law states that voltage and resistance are directly proportional, meaning that the doubling of one would result in the other being halved.  If the voltage was 50V and the current was 5A, then the resistance would be equal to 10Ω because:

        
        
V  /  I  =  R

        50V / 5A = 10Ω

Apparatus

In this experiment I will use:

  • A number of wires
  • An ammeter
  • A voltmeter
  • A metre stick
  • A piece of copper wire
  • Crocodile clips
  • A power pack.

Method

  • A circuit will first be set up with a power pack, an ammeter in series and a voltmeter in parallel with the piece of wire that will be varied in length.
  • As the power pack display is not at all accurate, a voltmeter will be connected directly with the power pack to make sure that it is set on 6 volts.
  • Once the voltage is set the thinnest wire will be attached to a ruler so that it is easy to measure the length of wire being used.
  • Two crocodile clips will then be attached onto the wire and into the circuit parallel with the voltmeter like in the diagram.
  • The pack will then be turned on and the readings on both the ammeter and the voltmeter will be recorded.
  • To see if the results are accurate, the resistance will then be calculated from the equation ‘R = V / I’.  
  • Readings will be taken with 100cm to 10cm wire pieces with 10cm intervals for a wide selection of wires to see patterns.
  • For even more variety of readings a variable resistor could be implemented into the circuit and on each length of wire three readings could be taken for maximum resistance, minimum resistance and somewhere in between.
  • We have decided to use the thickness of the wire as another factor, so on completion we will carry it out again with two more thicknesses, one wire of thickness gauge 36, one wire with thickness gauge 30 and the other with thickness gauge 28.

Diagram

image00.png

Making the Investigation both Safe and Fair

  • The power will not be left on too long to get the readings as temperature is also a factor that affects the resistance of a wire and leaving the wire would heat it up and therefore the results would not be accurate.
  • The power supply will be set to 6 volts for all the wire lengths so that the only factor that is varying is the length of the wire.
  • The same thickness wire will be used for each set of results, until the thickness is changed.
  • Results will always be taken at 10 cm intervals on the wire from 100cm to 10cm.
  • The voltmeter will always be in parallel with the piece of wire and the ammeter will remain in series with it throughout the investigation so that results can be taken.
...read more.

Middle

4.37

0.86

5.08

5.1

20

High

1.17

0.35

3.34

20

Medium

1.81

0.53

3.42

20

Low

4

1.18

3.39

3.38

10

High

0.67

0.38

1.76

10

Medium

1.09

0.61

1.79

10

Low

3.16

1.79

1.77

1.77


Results for Wire with Standard Gauge 30 (0.31 mm diameter)

Length of Wire (cm)

Resistance of variable resistor (high/medium/low)

Voltmeter Reading

(V)

Ammeter Reading (A)

Resistance (V/I) (Ω)

Average Resistance

(Ω)

100

High

3.01

0.21

14.33

100

Medium

3.66

0.25

14.64

100

Low

5.05

0.34

14.85

14.61

90

High

2.8

0.21

13.33

90

Medium

3.56

0.27

13.19

90

Low

5.07

0.38

13.34

13.29

80

High

2.6

0.22

11.82

80

Medium

3.39

0.29

11.69

80

Low

4.49

0.42

11.88

11.80

70

High

2.42

0.23

10.52

70

Medium

3.26

0.31

10.52

70

Low

4.91

0.47

10.45

10.50

60

High

2.23

0.25

8.92

60

Medium

3.06

0.35

9

60

Low

0.53

0.53

9.02

8.98

50

High

1.99

0.26

7.65

50

Medium

2.83

0.37

7.65

50

Low

4.65

0.61

7.62

7.64

40

High

1.73

0.28

6.18

40

Medium

2.55

0.39

6.54

40

Low

4.52

0.7

6.46

6.39

30

High

1.43

0.3

4.77

30

Medium

2.25

0.48

4.69

30

Low

4.25

0.92

4.62

4.69

20

High

1.07

0.33

3.24

20

Medium

1.62

0.5

3.24

20

Low

3.84

1.19

3.23

3.24

10

High

0.74

0.35

2.11

10

Medium

1.10

0.57

1.93

10

Low

3.19

1.77

1.80

1.95

Results for Wire with Standard Gauge 30 (0.31 mm diameter)

...read more.

Conclusion

If I was to repeat the experiment I do not think I could better the results much as I am very pleased with the accuracy. Next time though I could look at other factors like material.  This could be done much like the way that I carried out this experiment, the only difference being that I would not just use one material, I could use copper, nickel and chrome and find out which one offered the least resistance.  Temperature would be a hard factor to investigate as there is no way or really measuring the temperature of a wire with the equipment that is provided for us at school as a thermometer would be no good.   Again pressure could not really be completed within the school as we do not have a pressure cabinet and could not get pressure to desired levels.  Also we have to make check all the readings by hand as we have no way of connecting these up to a computer to check them automatically.  Also if I took more results next time, with not just three readings for each length, then the average would be that more accurate and so more reliable results would be recorded.  

Overall though I definitely feel that the investigation was a complete success at investigating how both thickness and length of the wire attribute to the resistance that is offered.


        Factors affecting the resistance of a wire

...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

    Investigating how the length of wire affects its resistance

    3 star(s)

    my results, as electrical equipments scarcely ever show the same, exact readings. They are all slightly inaccurate. Furthermore, the wire attached to the metre ruler could also have caused slight inaccuracy. The wire is not perfectly straight, and is rather irregularly bent, meaning that I may not have the exact length I wanted.

  2. Peer reviewed

    Investigation in resistance in wires

    5 star(s)

    We used our preliminary effectively to see what we needed to change; we changed many key factors but this helped make the test better. Variable DC power pack - To provide power into the circuit Connecting wires - To connect the circuit together Crocodile clips - To attach the Nichrome

  1. Resistance of a Wire Investigation

    This is when photosynthesis is being carried out at a constant rate. The reason that a "f 1/b2 did not apply was due to the apparatus used. The lamp that I used had a cover that directed the light energy somewhat.

  2. Resistance and Wires

    By recording the current (using the ammeter) and potential difference (using the voltmeter), change in resistance can be calculated. This data will be placed on a graph and analyzed. I will use various calculations to find the resistance of the wire (in Ohms), as different lengths of nickel-chrome are used.

  1. Physics Coursework Investigating Resistance of wires and its relationship to length.

    I had the resistance as my dependant variable. The experiment circuit: Preparing for Practical Before I started the actual test, I needed to decide what material to use and what voltage to have on the power pack. The voltage on the power pack goes from 2-12 but I decided to

  2. Investigate how mass affects the diameter of an impact crater.

    The calculations of the square root of mass are also tabulated below. VMASS (G) AVERAGE CRATER SIZE (MM) 2.23606798 45 3.16227766 52.66 3.87298335 63.33 4.47213595 66.66 5 75 5.47722558 79.66 5.91607978 82 Refer to graph 5. As can be seen from the graph the crater size increases at a constant

  1. Investigating how the length of a Wire affects its resistance.

    2 is correct and that the cross sectional area and/or area squared is directly proportional to resistance. Equation 3 will be tested using test values to confirm my hypothesis. Test values: resistivity of wire = resistivity of constantan = 2.8 Diameter = 0.05m = 5 cm Length of the wire doubled.

  2. Free essay

    Aim: the aim for this experiment is to check if the length of a ...

    Do the same for all the other ranges. Fair test: * to make the experiment fair I maintain the control variable which were: * The current flowing in the circuit should be the same for all the lengths using the variable resistor.

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