• 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

Resistivity of a Wire

Extracts from this document...

Introduction

Resistivity of a Wire

Aim:

The aim of this investigation is to see how the length of Nichrome wire affects its resistance

Pre-test Results:

Wire Type

Swags

Length of Wire

(cm)

Voltage

(v)

Current

(a)

Resistance

(Ω)

Constantan

26

10

20

40

13.5

27.5

56.4

0.4

37.5

687.5

1410

Copper

26

10

20

40

0.9

1.5

2.5

0.4

22.5

37.5

62.5

Nichrome

26

10

20

40

32.5

59.4

118.3

0.4

812.5

1485

2957.5

Pre-test Findings:

From my pre-test, I found out that using the nichrome wire would be best to use because it gave the both more reliable results and were also closer together. Constantan was not suitable for the investigation because it gave very inaccurate results- the range was very large. Copper was not suitable both because it had a very low resistance, and also heated up very fast, so could burn someone. Therefore I decided to use nichrome wire.

I also decided to use a wooden block to keep hold of the wire, because it will keep the wire taut and also to prevent anyone getting burnt.

Another thing I decided was to use digital multimeters because they give more accurate results- to 2dp- and can measure both the current and voltage on the same instrument.

The ranges of lengths I will be using for my final investigation are: 0.2m, 0.4m, 0.6m, 0.8m and 1.0m.

Fair Testing:

...read more.

Middle

   0.000000159

0.2m = 0.2 x (110 x 10-8) ÷ 0.000000159 = 1.38 Ω

0.4m = 0.4 x (110 x 10-8) ÷ 0.000000159 = 2.77 Ω

0.6m = 0.6 x (110 x 10-8) ÷ 0.000000159 = 4.15 Ω

0.8m = 0.8 x (110 x 10-8) ÷ 0.000000159 = 5.53 Ω

1.0m = 1.0 x (110 x 10-8) ÷ 0.000000159 = 6.92 Ω

Prediction Continued:

I also predict that the resistance is directly proportionate to the length of the wire. If you double the length of nichrome wire, so will the resistance. From my predicted results, I can see that when I double the length from 0.2m to 0.4m, the resistance almost doubles too, from 1.38Ω to 2.77Ω. In the same way, if I triple the length of wore from 0.2m to 0.6m, the resistance is once again almost triple, from 1.38Ω to 4.15Ω. This also works if I quadruple the length of the wire from 0.2m to 0.8m and if I increase the length of wore 5 times, the resistance also increases in the same way. This can be seen not only when using 0.2m of wore but also if I double the length of wore from 0.4m to 0.8m, the resistance is almost double too, from 2.77Ω to 5.53Ω. This is because there is 2, 3, 4, or 5 times the length of wore, which means that there will also be 2, 3, 4, or 5 times more nichrome atoms present in

...read more.

Conclusion

In order for the investigation to be fairer, I think the temperature of the wire should have been kept constant. This had an effect on the investigation, because from my research, I found out that another factor affecting the resistance in a wire was the temperature too. As the temperature of the wire increased, so did the resistance. This is because as the wire gets heated, the particles gain kinetic energy, therefore making the flow electrons harder. This makes the particles move around more, therefore colliding with the electrons, and blocking their way, and taking longer for the electrons to move to the other side of the wire. This results in an increase of resistance.  

It would be very difficult for the temperature of the wire to be kept constant. A water-bath would not be suitable because there would be a potential health hazard, as water is an excellent conductor of electricity.

There is however a device known as a thermocouple, which can help us check the temperature is at a constant level or not. How it works is that it is connected in the circuit. They work in the sense that if the temperature of the wire goes above a given temperature, the thermocouple stop working, therefore breaking the circuit and so will not work.


image10.png


image11.pngimage12.png

Zoya Khan         1354        13228

...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. An Experiment To Find the Resistivity of a Wire

    This error may have been encountered while measuring the length of the wire. This is because it simply was not very practical to hold a piece of wire straight, whilst holding it next to a ruler and then trying to accurately fix crocodile clips to the right part on the wire.

  2. Resistance of a Wire Investigation

    Overall, I felt that due to the small volumes of oxygen involved, my experiment was not as accurate as it could have been, however I believe it was accurate enough to support and justify my hypotheses. Improvements could have been made as I have stated, mainly by simply increasing the time taken.

  1. An experiment to find the resistivity of nichrome

    I then left the power pack to rest for a small interval of time before switching it on again to record the next set of readings. * I also kept the diameter of the wire constant by using the same piece of wire throughout the whole experiment.

  2. Measuring the Resistivity of a Wire

    The power supply will not exceed 3V as this a large supply may also cause the temperature inside then wire rise thus affecting the resistance. I will also use a switch so that the power will not be running when I do not require it to.

  1. Factors Affecting the Efficiency of a Wind Turbine

    A thermometer was placed behind the wind turbine to measure the temperature of wind blowing. In this case it doesn't measure well because as air moves it spreads out and cool down. By the time it has reached the thermometer it has already cool to low temperature.

  2. Investigating the resistivity of an unkown wire

    So the sum of all the "pds" across all the components in a series circuit is equal to the emf of the power supply. When the components in the circuit are connected in parallel, each has the same potential difference across it.

  1. Investigation of Resistivity of Nichrome wire

    The dimensions were 32 gauge and length of 1 metre. It was attached to the apparatus. The power supply was set to 2 volts and the current and voltage was measured using the voltmeter and ammeter respectively. Readings were recorded in the results table.

  2. Calibration of a Thermocouple.

    A problem with working with thermocouples is that it needs a sensitive voltmeter, able to detect a signal of the order of a thousandth of a volt. Too sensitive a detector, and there appears to be no temperature difference. Another problem is the problem of internal resistance of a source.

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