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What is the cause of resistance?

  1. Jun 28, 2007 #1
    Hello again
    My textbook states that: "Resistance of a given conductor is due to the collisions of free electrons with the ions or atoms of the conductor while drifting towards the positive end of the conductor."

    What is meant by "collision" here? If we think deeply, can the free electrons actually "collide" with the ions? If so, then what sort of collision is this? What do they collide with- electrons of the ion? If I say that the electrons decelerate while travelling because of the attraction exerted by the positively charged ions, am I wrong? Stronger the attractive force, more will be the deceleration.
    Secondly, why is heat produced due to resistance? One could say that due to decelaration, kinetic energy is converted to heat energy. But isn't friction the main cause for this conversion? Is friction the real cause then, or what?

    Awaiting your answers....

    Mr V
  2. jcsd
  3. Jun 28, 2007 #2
    In a metal, the thermal motion of ions is the primary source of scattering of electrons (due to destructive interference of free electron wave on non-correlating potentials of ions) - thus the prime cause of metal resistance.

    from wiki
  4. Jun 28, 2007 #3
    Can you explain it in a little more detail?

    Mr V
  5. Jun 28, 2007 #4


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    Mr Virtual, try thinking of the electrons and ions [of the lattice structure] as waves instead of particles. You should get a feel as to what that wiki article is talking about in terms of interference.
  6. Jun 28, 2007 #5
    Oh no! Not this interference thing again. I have had enough already with the confusions of Double-Slit experiment.
    OK, can I please get the link to that page in wiki?

    Mr V
  7. Jun 28, 2007 #6


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    I can't categorize this [do you mean like elastic or inelastic?], but the electrons lose their kinetic energy in the form of thermal energy.
    Yes. ions of the lattice structure.
    The localized effect of this is trivial.
    You answered your own question. But replace friction with "electrical friction", i.e ions of the lattice structure.
    Last edited: Jun 28, 2007
  8. Jun 28, 2007 #7


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