I am referring to one of the answers to this old question. I can't add comment to it because I don't have enough reputation. So here I rephrase the question: does resistance increase with length because of more scattering? Suppose that while doubling the wire length I also double the voltage across the wire. Then $R$ is doubled and so is $V$ hence you would get the same current. But obviously those charge carriers would experience more scattering.

That resistance increase with length because of more scattering does not seem to be right can also be seen from the statistical point of view. Keeping everything the same you should not expect the mean waiting time (for the next collision) to change when you lengthen the ``trip''.

Any objection to my opinion?

  • 1
    $\begingroup$ The only comment I would make is that you did not quite think the difference between "number of scattering events" vs. "number of scattering events per unit length" trough. $\endgroup$
    – CuriousOne
    Jun 28, 2016 at 2:56

1 Answer 1


This has to do with the definition of resistance.The metal of a conductor contains free electrons,but also some which remain tied to the atoms of the material.Resistance occurs when the free electrons meet with the other type,because they will try to reject each another,so the free ones will have their direction changed and lose energy.

When you increase the length of the cable ,you increase the number of atoms that stand in the way of the free electrons,thus there will be more bumps.


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