• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Factors Affecting the Resistance of a Metal Wire.

Extracts from this document...

Introduction

Physics AT1: Factors Affecting the Resistance of a Metal Wire.

Planning.

I am going to test which factors affect the resistance of a metal wire, of which there are four, these are: the length, the type, the width and the temperature of the wires. I will use the equation I=V/R to work out the resistance of the wires, after finding out the voltage when the current is altered.

I will use a variable resistor to vary the current throughout the circuit and take readings of the voltages corresponding to that current.

In order to make this experiment fair; I will keep the width, temperature and type of wire constant. I shall investigate the changes in resistance when the length of the wire varies as this is the easiest variable to change because monitoring temperature is difficult, as is being certain of the width of a wire. I am not changing the type of wire because we do not have many different types available to us in school. I will keep the current small so that the wires do not overheat; otherwise there will be another change in variables. The increase in the temperature is dangerous, which is why this variable is kept constant.

...read more.

Middle

Copper wire has a low resistance, therefore, voltages are too difficult to read, which is why this type of wire shall not be used in this experiment.

Nichrome wire of diameter 0.457mm  is the better of the three wires to use because the values are clearer to read. There is a smaller resistance and it does not exceed the maximum voltage (3 x 0.85V = 2.55V).

I shall use Nichrome wire of diameter 0.457mm for this experiment. The temperature will remain constant so this cannot affect experimental values of the resistance. I will maintain the temperature by using a low current and I using lengths of wire above 20cm to prevent the wire from overheating.

The maximum length of wire available for use is 3m (300cm). I shall use lengths 40cm, 80cm, 120cm, 160cm, 200cm, 240cm, and 280cm. This covers the majority of the wire length. I have chosen seven values because when the average resistance is plotted on the graph, it is more accurate and clearer to read.

I shall measure the voltage, and then  calculate resistance, for each current three times in case any anomalies appear. Should there be an anomaly, I will take the average of just two values and exclude the anomaly.

...read more.

Conclusion

The voltages in my table hardly ever reached over 2V so if I carried out this experiment again, I would prefer to use a range of sensitivity 2V for more accuracy.

This experiment could be carried out using data-logging to both speed it up and to give more accuracy. I could also use different wires to see if my conclusion is true for other types of metal wires.

The points plotted on my graph were very close to my line of best fit, proving that the length of wire and the average resistance are directly proportional.

There was one anomaly within my results, which I have highlighted. When the reading was taken, the wires were touching, causing it to short-circuit. Next time, for more accurate results, I would make sure the wires were not touching.

For greater reliability, I could do more repeats, although I think if I did do more repeats, they would be very similar to those I have already taken.

I think my evidence is sufficient to support a firm conclusion that resistance is directly proportional to the length of a metal 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

    The factors affecting the resistance of a metalic conductor.

    4 star(s)

    Below are graphs that have the current (I) against the voltage (V) of the factors affecting the resistance of the wire. Effect of length [cm] on resistance: This graph shows 3 wires of different lengths, and shows us that as the length of a wire increases the resistances increases as seen in the steepness of each slope.

  2. Marked by a teacher

    Factors Affecting The Resistance Of A Metal Wire.

    4 star(s)

    Then I will do two repeats of the experiment, to highlight any anomalies and to get the most accurate results possible, and use the averages for the resistance. Method/Strategy 8. The circuit will be set up as in the diagram above, with the measured amount of wire connected.

  1. Discover the factors affecting resistance in a conductor.

    It does not state what must occur, it simply describes the behaviour of materials. This of course applied on to metals, ionic solutions and in some cases carbon. Many conductors do not obey Ohms Law. Current-Voltage Graphs: Ohm's Law The results from completing a circuit where voltage and current can

  2. Resistance and Wires

    of the range bars would have been recorded later on when the wire was hotter. If I were to conduct this experiment a second time, I would increase the amount of time that the power was turned off, to ensure a sufficient amount of time to allow the wire to fully cool down.

  1. An experiment to find the resistivity of nichrome

    My graph should show that the length is proportional to the resistance. The diagrams below show my prediction and should explain it more clearly: Because the length of the wire is only half the length of the wire below there should be half the number of collisions between the electrons and the atoms.

  2. Factors affecting Resistance of a wire

    Also check that the ammeter is picking up some current. If not, again check to make sure the wires are properly connected and adjust accordingly. Turn off the power supply. Now connect the voltmeter. Ensure that the wire is connected at 10cm. Turn on the power supply to approximately 3V.

  1. Investigate one or more factors affecting the resistance of metal wires

    and I = electrical current (measured in Amps (A)). Limitations of Ohm's Law If Ohm's Law is to be obeyed, the temperature of the wire must remain constant, as mentioned above. It is also necessary that all the physical conditions remain constant.

  2. To investigate the factors affecting current in a wire.

    So at 20 C: Copper has a resistivity of 1.78 * 10-8 ? Nickel Chrome has a resistivity of 110 * 10-8 ? Silver has a resistivity of 1.66 * 10-8 ? Voltage The potential difference or voltage is the energy that is given to each charge as it passes through the power source.

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