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Potential energy of an electron

  1. Dec 12, 2014 #1
    .(1)Electron's potential energy decreases when it moves from lower to higher potential,right?And i also want to verify few more things on which i am doubtful .(2)Why when electron passes through resistance it's potential energy decreases?I think because it require energy to pass or cross resistance as it is hindrance for flow of electron so when electron crosses this it does work i.e uses energy that's why it's energy which was totally in the form of potential energy get reduced,so that's why when electron passes through resistance it's potential energy decreases.right?
    (3)But why electron's energy is totally in the form of potential energy,as it was moving through circuit it should have kinetic energy also.Is kinetic energy negligible as mass of electron is very small .I don't think so it is right.And if it has kinetic energy, why after crossing resistance only it's potential energy decreases,why not kinetic energy decreases i.e why not electrons get slow down after crossing resistance?
    Although i have put 3 questions together we can discuss one by one.Just guide me where i am wrong.
  2. jcsd
  3. Dec 12, 2014 #2


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    2017 Award

    Staff: Mentor

    Depends on what you mean. "Electric potential" - yes. "Potential for the electron" - no.
    Something in that direction, yes. It does not work (=ordered mechanical energy), however, it heats up the resistor.
    Kinetic energy is negligible as both [mass per charge] and velocity are very small. The net motion in typical circuits is somewhere in the range of millimeters per second.
    It can be different, that depends on the details of the cables. It does not matter as it is negligible.
  4. Dec 12, 2014 #3
    i didn't understand this point.
  5. Dec 12, 2014 #4
    All you have to do is use "s" after electron, they are plural, electrons. You can't single one out and look at it, they are a collective of potential.
  6. Dec 12, 2014 #5
    oh,you mean i should say electrons move from lower potential to higher potential but yet their potential energy decreases.Right?
  7. Dec 12, 2014 #6


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    The potential is attribute of the electric field. The potential energy of the electron is PE=-eU at a place with potential is U. Moving to t higher potential, the potential energy of the electron gets lower.
  8. Dec 12, 2014 #7
    Thanks.Now it's clear.
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