• 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

To investigate the effect the length of a wire has on the resistance

Extracts from this document...

Introduction

Reshmal Barot

11/4

Aim: To investigate the effect the length of a wire has on the resistance

V = I x R

Voltage = Current x Resistance

What is electric current and how is it measured?

Electric current is defined as the rate of flow of electric charge. Electric current is measured as the amount of charge which flows past a particular point in a particular point. Current is measured in amperes, but when written can be shortened to ‘A’ or ‘amps’. Below is the equation used to measure current in amperes.

Current (amps)    =         charge passing in coulombs

Time interval in seconds

An ammeter is used to measure electric currents, the ammeter measures how much charge is passing through it. An ammeter should be connected in a series circuit; also the positive terminal of the ammeter should be connected to the wire coming from the positive power supply. However it does not matter where you put the ammeter in the circuit, as long as the circuit doesn’t branch anywhere.

In order to for current to flow in a circuit a potential difference must exist.

What is potential difference and how is it measured?

Potential difference is also known as the voltage. The potential difference between two points in a circuit is defined as the amount of electrical energy changed to other forms of energy when a coulomb of charge passes between those two points.

...read more.

Middle

0.4

0.3

0.75

0.79

0.38

0.3

0.79

0.38

0.3

0.83

25

0.4

0.4

1

1.05

0.38

0.4

1.05

0.36

0.4

1.11

30

0.44

0.6

1.36

1.39

0.4

0.6

1.5

0.38

0.5

1.32

35

0.46

0.8

1.74

1.65

0.44

0.7

1.6

0.42

0.7

1.6

40

0.44

0.8

1.81

1.67

0.42

0.8

1.9

0.44

0.8

1.81

As well as being able to select the suitable equipment, this test showed difficullty in building a circuit. At first I found setting up a voltmeter/ ammeter and variable resistor into the circuit quite difficult, but whilst practicing in the preliminary test, I became fairly confident and built it accurately and promptly.

Method:

In my method I followed my plan, leaving it unchanged. (The plan can be found on page 4.) I repeated this process six times, to ensure accuracy of results and to solve any anomalous results. The measurement of the length of the wire was done in multiples of five, the resistance board included a 40cm wire, and therefore eight different lengths were experimented on, each going up by 5cm. After experimenting with the power supply on two volts, I trialed the test again, but this time setting the power supply on four volts.

Results

The table below shows my results whilst the power supply was set on two volts.

Length (cm)

Current    (amps)

Voltage (volts)

Resistance (ohms)

Average total resistance (ohms)

...read more.

Conclusion

If doing this test again I would like to develop a way to control the temperatures of the wires, giving me a better indication of the relationship. Also so that I have even greater accuracy I would use newer and more accurate ammeters and voltmeters over a wider range of lengths. I would also like to look into how the diameter affects the resistance.

It was important to have control over the factors that affect resistance; a key factor was the length of the wire; I controlled this by straightening out the wire before measuring to make sure there were not any kinks that would add to the length. One factor I felt I had lees control over was the potential difference applied, I was reliant on the power pack setting and in doing this investigation again I would look into setting greater control.

Page  of

...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

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

    3 star(s)

    The electrons skip from atom to atom in the metal in retort to the electric field in the circuit. A conductor with a larger cross-section allows more electrons to relate with the field. Because there is more current with a given voltage, a conductor with a larger cross-section has lower resistance.

  2. Investigating how the resistance of Nichrome wire depends on its length

    Ammeter An ammeter is a measuring instrument used to measure the flow of electric current in a circuit. Electric currents are measured in amperes, hence the name. Voltmeter It is a measuring instrument for measuring the volatge between two points in an electric circuit.

  1. An experiment to find the resistivity of nichrome

    How I will perform the experiment is by, taking a wire of a certain Gauge and of 50 cm length (keeping all variables except the variable being investigated constant) Then use the power supply, voltmeter, ammeter, crocodile clips, wires and measuring devices (ruler).

  2. How does length and width affect resistance

    In addition, if the length of the wire was trebled or quadrupled, then the resistance would also treble or quadruple. This in theory would mean that because at 100cm there would be a resistance of 14.65 Ohms at 20 cm it should be 2.93.

  1. Electromagnetism - investigating what effect increasing the number of turns in a coil on ...

    I feel I have received these results because, in a piece of iron that is unmagnetised, the domains will all point in different directions. As they are doing this there is no true north seeking or south-seeking pole in the piece of iron as the domains cancel each other out, therefore the piece of iron will remain unmagnetised.

  2. Investigating The Effect Of Resistance On A Capacitor Circuit

    0 0 0.092 0.466 1.3 25 0 0 0.085 0.445 1.272 25.5 0 0 0.085 0.424 1.244 26 0 0 0.078 0.41 1.215 26.5 0 0 0.071 0.396 1.187 27 0 0 0.064 0.375 1.159 27.5 0 0 0.057 0.36 1.138 28 0 0 0.057 0.346 1.109 28.5 0 0

  1. investigating the factors that effect the resistance on a length of nichrome wire

    It is measured in volts (V) and by using a voltmeter. To make a current flow through a resistance there must be a voltage across that resistance. Ohm's Law shows the relationship between the voltage (V), current (I) and resistance (R).

  2. To devise an experiment to investigate on how the resistance of nichrome wire depends ...

    Therefore this variable will be controlled without us actually having to do anything. Scientifically however we can say the larger the cross-sectional area of the conductor, the more electrons are available to carry the current, meaning the lower the resistance.

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