• 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 Wire.

Extracts from this document...

Introduction

FACTORS AFFECTING THE RESISTANCE OF A WIRE

Resistance is measured in Ohms (Ω)* and the amount of resistance determines how much current is allowed to flow by a component. Electricity is conducted through a conductor, in this case wire, by means of free electrons. The number of free electrons depends on the material and more free electrons means a better conductor, i.e. it has less resistance. For example, gold has more free electrons than iron and, as a result, it is a better conductor. The free electrons are given energy and as a result move and collide with neighbouring free electrons. This happens across the length of the wire and thus electricity is conducted. Resistance is the result of energy loss as heat. It involves collisions between the free electrons and the fixed particles of the metal, other free electrons and impurities. These collisions convert some of the energy that the free electrons are carrying into heat. There are several factors that affect the resistance of a wire.

Length

...read more.

Middle

* Ohm's Law states that the current through a metallic conductor (e.g. wire) at a constant temperature is proportional to the potential difference (voltage). Therefore V¸ I is constant. This means that the resistance of a metallic conductor is constant providing that the temperature also remains constant. Hence, the resistance of a metal increases as its temperature increases. This is because at higher temperatures, the particles of the conductor are moving around more quickly, thus increasing the likelihood of collisions with the free electrons.

image03.png

image01.png

image02.png

I am going to investigate how the length of a wire affects its resistance. This is the circuit that I will use to measure both the current through and the voltage across the wire. For this I am using a Voltmeter and an Ammeter. I have performed a preliminary experiment (and set up this test circuit independently) in order to establish how many readings to take across a meter (m) and I have found that taking readings every five centimetres would be sufficient.

...read more.

Conclusion

There is one truly anomalous result and that was for a piece of wire of length 15cm. For this mistake I can only blame meter inaccuracies (if I had a more precise meter that went to ten decimal places instead of two then all of the results would have been more accurate), loss of detail through gaining averages and possibly human error in reading the meters or in the calculations. If I had used a more accurate meter that allowed me to measure current and Voltage to eight decimal places instead of two then all of my results would have been more accurate.

Evaluation

I feel that my results are reliable enough to support my predictions and conclusions.If I was to do this experiment again I would make would be to use pointers instead of crocodile clips , I would do this because pointers would be more accurate. The pointers would be more accurate because the tips have a much smaller area than the crocodile clips giving a more accurate measurement of the length of wire. The wire measurement was not correct. The solution to this is to measure the lengths more carefully and ensure that the wire is pulled tight against the metre rule.

...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)

    If this is carried out over a larger distance there will be more atoms for the electrons to hit. Therefore resistance is proportional to the length of the conductor, providing the temperature, cross sectional area and material of the conductor are kept constant.

  2. Discover the factors affecting resistance in a conductor.

    Dependant Variable The dependant variable is the change that will occur in the experiment that we are unable to control. In this case, it will be resistance, owing to the change of conditions in the circuit. We will then measure the resistance using a multimeter, and later an ammeter and a voltmeter, using R=V/I (explained later).

  1. Factors Affecting the Efficiency of a Wind Turbine

    When the angle is small, there is a high lift force and less drag. This is known as lift-drag ratio and in this situation the ratio is high when the angle is small. Each shape has its best angle of attack that gives the greatest lift-drag ratio.

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

    The results did agree with the prediction. However the half-life can vary a lot because it mostly depends on how the best-fit curve is drawn. And the isotope is meant to be decaying but there are slight fluctuations (increases) in the activity.

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

    * The best voltage(s) to use so that the wire does not get too hot. * What type of materials to use in my final experiment. * Appropriate apparatus that will help me obtain precise evidence. * A suitable method of conducting this experiment.

  2. Investigation into the factors affecting the resistance of wire

    I expect the resistance to roughly double when the length doubles. I expect the results from the test on diameter to show an increase in diameter and so cross sectional area to bring a decrease in resistance. This is because with a wider "passage" for the electrons to pass through

  1. An investigation into the factors affecting the resistance of a wire.

    I can now work out the resistance using the current and Voltage: R=V/I (ohms law) R - resistance in ohms (?? ohms) V - voltage (volts) I - current (amperes) I have discovered the circuit itself can resist the flow of particles if the wires are either very thin or very long.

  2. Investigating the factors affecting the resistance in a piece of wire.

    The variables that I will keep the same will be: * Material of wire-either Copper, Constantan or Nichrome. * Density of wire * Temperature of wire * Shape of wire- straight * Voltage- constant voltage of 2 volts. Circuit diagram for preliminary experiment Method 1 Set up the circuit as

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