Investigate factors that affect resistance

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Investigate factors that affect resistance

Introduction

        During recent physics lessons, we have been studying resistance and what factors may affect resistance. So far, we have learnt that…

  • Resistance is the opposition to the flow of electrical current
  • It is caused by electrons colliding with the atoms in a metal
  • The more collisions there are, the greater the resistance will be
  • When electrons collide with atoms, the atoms absorb the kinetic energy  from the electrons and vibrate faster
  • This means the atoms and therefore the material is getting hotter
  • The increased vibrations of the atoms make it harder for the electrons to get past and therefore the resistance is increased
  • Resistance is the ratio of voltage divided by current
  • Ohm’s Law states that for a metallic conductor the current through the wire is directly proportional to the voltage across its ends as long as the temperature remains constant

We are now going to investigate further into what factors affect resistance and how they affect it.

Variables

        The variables that I could use in my investigation are…

  • Atomic structure of the metal (type of metal)
  • Temperature
  • Length of the wire
  • Thickness of the wire

These are all factors that would affect resistance, but I am only going to investigate one factor.

Chosen variable

        The variable that I have chosen to use in this investigation is the length of the wire. I have chosen to use this variable as it would be the easiest to do as the length of wire is easy to measure and would probably give the most accurate results due to this. I have chosen not to change th type eof metal as this cannot be measured and would therefore be harder to analyse. It would also be more difficult to measure the thickness of the metal accurately with the equipment available. Changing the temperature of the wire would be hard to control making it harder to compare and analyse my results. Therefore, I have decided to use the length of the wire as my variable.

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Prediction

        By using what I have already learnt about resistance, I predict that the longer the wire, the greater the resistance will be, for example, if the length of the wire if doubled, then the resistance will also double. This is  because in a longer piece of wire, there will be more metal and therefore more metal atoms, and this means that there will be more collisions taking place between the metal atoms and the electrons in the current. This will therefore mean that the resistance will be greater as more collisions mean a greater resistance in the wire. ...

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