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This is a follow up question to my earlier question here:

Increasing the Voltage, Ohms law, what am I missing?

A short summery of what was the problem in my original question is this:

We have a circuit with a power source and a resistor. When we increase the voltage we increase the energy to each electron(voltage is energy per charge). If we use classical mechanics and assume that the work done by the resistor is constant, then the electron would accelerate. In Dales answer he explained that as we increase the voltage we also increase the energy removed by the resistance. The force that the resistance has on the electron increases with current density. That's why we will get a new constant current, and not an increasing current. He also explained that we need QED to explain what is going on.

I am wondering if it is possible to explain this phenomenon to someone who hasn't taken quantum physics? Why does exactly the work the resistor does increase when the current increases? Can these concepts be explained (fairly) simply?

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  • $\begingroup$ en.wikipedia.org/wiki/Drude_model $\endgroup$
    – Sebastian Riese
    Commented Mar 11, 2021 at 17:42
  • $\begingroup$ @SebastianRiese From the answer I got from Dale he said that the Drude model wasn't correct and that we need to use quantum physics instead. $\endgroup$
    – user394334
    Commented Mar 11, 2021 at 17:44
  • $\begingroup$ That is true (although the quantum result for the conductivity formally looks just the same as the Drude result, you just have to interpret the quantities a bit differently). If you want an explanation that's correct in detail, you need advanced quantum mechanics – the Drude model offers an easy to understand explanation of the linear relation. $\endgroup$
    – Sebastian Riese
    Commented Mar 11, 2021 at 17:48
  • $\begingroup$ @SebastianRiese So there is no way to explain it simple qualitatively why the work the resistance does increase with increasing current(using quentum mechanics)? I completely understand that it would be too difficult to derive the equations etc.. $\endgroup$
    – user394334
    Commented Mar 11, 2021 at 17:52
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    $\begingroup$ You need either to do linear response theory (and why the higher orders are negligible) or discuss the quantum Boltzmann equation to do this. Both require understanding of a lot of concepts well beyond elementary QM. In my opinion, explaining the Drude model (and its limitations due to QM, namely the Fermi statistics) is a better path didactically. $\endgroup$
    – Sebastian Riese
    Commented Mar 11, 2021 at 18:10

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