• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12

Resistivity of a Wire

Extracts from this document...


Resistivity of a Wire


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

Pre-test Results:

Wire Type


Length of Wire












































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.



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.


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.



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 nichrome

    I decided to chose 8 different lengths between 30-100cm because when I did a preliminary experiment I found that these lengths gave accurate results and that 8 readings was sufficient enough for me to plot a st. line graph and draw a good line of best fit through the points.

  2. Resistance of a Wire Investigation

    The lamp will be adjusted to different distances from the plant to try and obtain different results. Photosynthesis Equation: 6CO2 + 6H2O light energy & chlorophyll C6H12O6 + 6O2 Variables: Experimental Variable- Light intensity is to be the variable explored in this investigation.

  1. Measuring the Resistivity of a Wire

    Length (m) Area (m�) Current (A) Voltage (V) 22 9.00E-04 0.5 6.36E-07 0.28 0.41 22 9.00E-04 0.5 6.36E-07 1.37 2.01 22 9.00E-04 0.5 6.36E-07 0.27 0.39 22 9.00E-04 0.5 6.36E-07 0.29 0.42 22 9.00E-04 0.5 6.36E-07 0.34 0.49 22 9.00E-04 0.5 6.36E-07 0.42 0.61 22 9.00E-04 0.5 6.36E-07 0.53 0.77

  2. 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.

  1. Determination of the resistivity of nichrome wire

    This causes more collisions between the electrons and the atoms as the atoms are moving into the path of the electrons. This increase in collisions means that there will be an increase in resistance. An increase in resistance will lead to an increase in resistivity.

  2. Investigating the resistivity of an unkown wire

    the resistance is increased). An analogy of this theory is to imagine an individual walking through a crowd of people (who in this case are metal ions and the individual the electron). If the crowd are standing still (similar to soldiers on parade), the individual can easily move through by walking along the lines between the soldiers.

  1. Investigating the resistivity of constantan

    Now I know that I should be looking for this kind of pattern for my real experiment. After I have collected my results, I will plot 10 graphs; one for each length.

  2. Identification of an unknown test wireThrough the experimental determination of it's Resistivity, p.

    and then plot a graph of RA by L, and the gradient for this will give me Resistivity. Constants Voltage- this will need to be kept the same, because if the voltage increases then the current will increase, and as current increases, resistance decreases.

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