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When revisiting Ohm's Law, I wondered why (I know it's experimentally derived) the voltage change between two points would depend on current. I could understand this dependence with total energy dissipated in moving a current across a resistor but I can not understand why the P.D. (i.e. the work done per unit charge) depends on the current being passed. Essentially, I'm asking why does the amount of energy needed to move a single unit charge depend on how many charge carriers there are with it?

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  • $\begingroup$ Do you understand why it takes more force to push a cinder block across a soccer field than to push it across an ice hockey rink? $\endgroup$ – The Photon Aug 1 '20 at 23:57
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    $\begingroup$ Does this answer your question? Why, microscopically, is the voltage drop across a resistor affected by the current through it? $\endgroup$ – Thorondor Aug 2 '20 at 4:44
  • $\begingroup$ @ThePhoton Yes, but that applies to resistive forces like friction, my question would relate more to why the amount/mass of the cinder block affect the pressure (rather than the total force itself as the force would scale up with mass)? $\endgroup$ – user77287 Aug 2 '20 at 7:22
  • $\begingroup$ @Thorondor It answers the sense that the current is dependent on V/R, but I still don't understand then why the amount of energy per unit charge would affect how much charge goes through, why not I = W/R where W is the work done? $\endgroup$ – user77287 Aug 2 '20 at 7:25