• 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

Investigating how the length of a wire affects its resistance

Extracts from this document...

Introduction

Physics Coursework

Investigating how the length of a wire affects its resistance

Sean Connolly 12M

        I have decided for my coursework that I will investigate how length affects the resistance of a wire.

Background information on resistance

In 1826, George Ohm discovered that:

                The current flowing in a metal is proportional to the

                Potential difference across it providing the temperature

remains constant.

He then developed a formula: -

Resistance (R) = Voltage (V) ÷ Current (I)

Resistance is a measure of how easily the electrons can move through a metal. Therefore a low resistance means that the electrons can move more easily.

Aim

In my investigation I shall try to see if the length of a piece of wire affects its resistance.

Prediction

I predict that the length of wire will affect its resistance. I am making this prediction because all metal s contain electrons in their outer shell. The larger the surface

...read more.

Middle

Results

For each length of wire I will use a table like this: -

Setting

Voltage (V)

Current (A)

Resistance (Ω)

1

2

3

4

5

image20.pngimage20.pngimage21.png

I will then get the average resistance by adding all five resistances up and diving by 5.

I will then draw 5 separate graphs for each length showing voltage against current.

image10.png

image22.pngimage23.pngimage22.pngimage28.pngimage24.pngimage27.pngimage26.png

Then I will incorporate all 5 lengths into one graph to show the changing trends. image29.png

image12.pngimage21.png

image31.pngimage30.png

image32.png

Finally my last graph will include length against average resistance.

image12.png

image29.png

Table of Results

10 CM

Setting

Current (A)

Voltage (V)

Resistance (Ω)

1

0.6000

0.1500

0.2500

2

0.5000

0.1255

0.2510

3

0.4000

0.1015

0.2538

4

0.3000

0.0760

0.2533

5

0.2000

0.0510

0.2550

Average Resistance =  0.2526Ω

20 CM

Setting

Current (A)

Voltage (V)

Resistance (Ω)

1

0.4500

0.1500

0.3333

2

0.3500

0.1180

0.3371

3

0.2800

0.0920

0.3259

4

0.2000

0.0653

0.3265

5

0.1200

0.0400

0.3333

...read more.

Conclusion

image36.pngimage35.pngimage38.pngimage37.pngimage34.pngimage43.png

X1= 0.3000, Y1= 0.0760, X2= 0.6000, Y2= 0.1500

Y2-Y1÷X2-X1

= 0.1500-0.0760÷0.6000-0.0760

=0.0740÷0.3000

= 0.2467Ω

My average resistance for 10Cm was 0.2526Ω. My answer for the resistance of the graph was 0.2467Ω. This shows that my graphs and tables are very accurate and that the straight line on the voltage-current graph represents resistance.

I feel that my results gained were reliable as all my results tallied. But at times the voltage and current readings on the voltmeter and ammeters flickered giving me at times, inaccurate results. If I were to repeat the experiment I would use much more up to date meters. I feel that some of my graphs did not turn out the way I would have liked them because I didn’t take enough readings in the practical. If I had have taken more results them my graphs would have been much more accurate. I do though however feel that the evidence is sufficient to support my predictions as my results turned out to be accurate and they supported my predictions well.

...read more.

This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal Physics 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 AS and A Level Electrical & Thermal Physics essays

  1. Peer reviewed

    Measurement of the resistivity of Nichrome

    5 star(s)

    Graph B (Wire B) Red line gradient 0.106 0.198 Best fit line gradient 0.104 0.196 Blue line gradient 0.102 0.194 Calculate the uncertainty of gradient Maximum value of uncertainty of gradient (Max) = (Red line gradient/Best fit line gradient) -1 Minimum value of uncertainty of gradient (Min)

  2. Investigate how the temperature affects the resistance of a thermistor.

    I also conclude that the behaviour of a resistance is that from a low temperature the resistance of a thermistor drops quickly and then begins to decrease at a slower rate until it reaches a point at which the resistance stays at a constant unit which I think would be 0?

  1. Thermistor Coursework

    R2 This is the apparatus that I will use: One lab power pack of 5v One thermistor (resistance to be decided) One variable resistor (resistance to be decided) One glass thermometer 0°C to 100°C One 200 cm3 beaker A voltmeter/ohmmeter Two crocodile clips Five banana-plug wires One kettle Ice cubes Diagram of setup.

  2. resistivity if a nichrome wire

    Resistance ? length Thickness of the wire: The thinner the wire or the smaller the cross sectional are of the wire, the higher the resistance. This is because there is a reduced amount of space available for the current to flow through (the electrons).

  1. Investigating the effect of 'length' on the resistance of a wire

    Accurate resistors can be made from metal wires. A variable resistor is used in a circuit to change the current. For example, a variable resistor in series with a motor could be used to control the speed of the motor.

  2. To investigate how the temperature affects the resistance of a thermistor.

    0C 500 680 472 40 0C 412 370 394 *RETEST - original resistance = 672? Temperature of Thermistor (0C) Average Resistance (?) 100C 1073? 150C 851? 200C 764? 250C 691? 300C 636? 350C 551? 400C 392? Graph: (on following page)

  1. Finding the Resistivity of a Wire

    For example, if the average measurement had been 0.95mm instead of 0.90mm, using the same calculations the area would have instead been 7.09x10-7m2, compared to 6.36x10-7m2. o The only slight chance of systematic error would be on the ruler, due to measuring from the inside of the crocodile clips.

  2. Free essay

    Resistance of a wire

    experiment will now produce more accurate results, I will ensure this even further by repeating each test 3 times with 30seconds cool down between each test. This will be much more time consuming but will ensure that I get accurate results.

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