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Homework Help: How do electrons know that there are other resistors?

  1. Apr 25, 2015 #1
    If there is only one resistor, the voltage drop is equal to the potential of the positive terminal. The voltage drop across more than one resistor is directly proportional to the value of each resistor. But the total drop in potential difference must be equal to the potential of the positive terminal.

    My question is - how do the electrons know that there are other resistors in the circuit and to only give part of their potential energy to some resistors and the rest to another??

    Also, if the electrons are given potential energy from the power source, isn't that converted to kinetic energy to move them through the wires? How are they able to give energy to the resistors if they are using up their energy moving through the circuit?

    If a circuit was set up without any resistors at all, where does the energy go??
  2. jcsd
  3. Apr 25, 2015 #2


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    Staff: Mentor

    How do they know it for a single resistor?
    I don't think electrons are a good model if you want to understand circuits, and sentient electrons are certainly not a good model.
    Energy is lost only if there is a resistor - that is the point of resistors. The energy is converted to heat. Kinetic energy is completely negligible.

    There is no ideal power source - they always have something like an effective resistance even if the remaining circuit is made out of superconductors.
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