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Wire Resistance (Please check this)

  1. May 20, 2006 #1
    Hey. I'm invesitgating how resistance in a nichrome wire is affected by the length of wire. Please check my prediction for me:

    "I predict that when I increase the length of wire, the resistance in the circuit will increase. This is so as there are more atoms in the wire for the electrons to collide with in a longer wire, stopping electrons and creating resistance. As the wire increases in length, there are more atoms, so as the electrons flow through the wire, the greater number of atoms causes a higher resistance. There are more ‘barriers’ and ‘obstacles’ for electrons to pass. The voltage (the electric potential difference between two points) therefore increases. As electrons pass through the wire, they collide with the high number of atoms and transfer kinetic energy over to them. As atoms are fixed and can just vibrate, the additional energy they receive results in the kinetic energy to be transferred into heat energy, thus resulting in a high temperature of wire."

    I wrote that myself and all I'm asking you is to see if that is all scientifically correct. Any other stuff to add would be nice though. Thanks.
     
    Last edited: May 20, 2006
  2. jcsd
  3. May 20, 2006 #2

    Hootenanny

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    Scientifically correct for what level? GCSE? I would prefer 'slowing' electrons rather than 'stopping' them.

    ~H
     
  4. May 20, 2006 #3
    Yeah GCSE Coursework. Anything else that I could add into that prediction? Thanks by the way
     
  5. May 20, 2006 #4

    Hootenanny

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    Oh, one more thing that I've just noticed, you should replace atoms with ions. Google 'Metallic Bonding' for more information, but basically in metals, there is a lattice of postive metal ions, surrounded by a sea of delocalised electrons (you will probably of heard these terms in chemistry).

    ~H
     
  6. May 20, 2006 #5
    So this edited version is alright?

    "I predict that when I increase the length of wire, the resistance in the circuit will increase. This is so as there are more ions in the wire for the electrons to collide with in a longer wire, slowing electrons and creating resistance. As the wire increases in length, there are more ions, so as the electrons flow through the wire, the greater number of ions causes a higher resistance. There are more ‘barriers’ and ‘obstacles’ for electrons to pass. As electrons pass through the wire, they collide with the high number of ions and transfer kinetic energy over to them. As ions are fixed and can just vibrate, the additional energy they receive results in the kinetic energy to be transferred into heat energy, thus resulting in a high temperature of wire."
     
  7. May 20, 2006 #6

    Hootenanny

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    Sorry, but I should have said, positive ions, or metal [lattice] ions. But yeah, it looks ok. If you wish you could also comment on the positive feedback system, i.e. increased temperature leads to an increased resistance which leads to an increased temperature ad infinitum. You may also wish to comment on this in your evaluation, not leaving the circuit connected to long do to increased heat energy etc...

    I've only had a glance through it, so you may wish to check back later to see if anyone else has picked anything up.

    ~H
     
  8. May 21, 2006 #7
    Anyone else wanting to check it out any help?
     
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