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B Why we say that electrical energy is power over time p x t

  1. Dec 27, 2017 #1
    Greeting .

    how electrical energy can be power over time when electrical energy is actually potential energy .

    from a lot of sources (wiki ,study.com..) comes the information that electric energy is potential or kinetic energy in other sources is said to be electric power p x t so i am confused by this

    Thank you.
    Last edited: Dec 27, 2017
  2. jcsd
  3. Dec 27, 2017 #2


    Staff: Mentor


    It sounds like you are getting confused by definition of words.

    Electrical energy is not like mechanical energy. Mechanical potential and kinetic energies are not like electric energy.

    The electric potential is not energy.

    One can say that power is rate of change of energy.

    In order to have electric power flow, we must have both a potential difference (V) and current flow (I), P=V*I. If V is zero or if I is zero, then P is zero.

    In words, power is to energy as speed is to distance. I assume you know how speed and distance are defined and how they relate to each other.
  4. Dec 27, 2017 #3

    ok i understand what you men but what then wiki and study .com constantly saying the electrical energy is potential energy i will quote :

    Electrical energy is potential energy, which is energy stored in an object due to the object's position. Well, in terms of electrical energy, the object is the charged particle, and the position is the location of that charged particle within the electric field. The charged particle will have the potential to move, or to do work, due to the force of the electric field.
  5. Dec 27, 2017 #4


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    Power is the rate at which energy is used so..

    Power = ∆energy/∆time

    Rearrange to give

    ∆energy = power * ∆time

    This work for all forms of energy.
  6. Dec 27, 2017 #5


    Staff: Mentor

    The wikipedia article applies to only one circumstance. That is when charged particles are brought closer together it takes energy to do that, and the electric potential is proportional to that energy.

    There are other ways to create power, chemical energy is one, and moving a wire through a magnetic field is another. That wikipedia paragraph does not describe those.

    In the future, if you cite a wikipedia article, also give a link to the article so that we can see the context.
  7. Dec 27, 2017 #6

    this is not from wiki this is from study .com link is https://study.com/academy/lesson/what-is-electric-energy-definition-examples.html
  8. Dec 27, 2017 #7


    Staff: Mentor

    It simply doesn’t matter. Power is the rate at which energy is transferred. It can be potential energy or kinetic energy or whatever. The type of energy transferred is not relevant, the rate at which it is transferred is always called power.
  9. Dec 27, 2017 #8
    ok but i repeat again whay is then p x t called electrical energy how we can have 2 definition of electrical energy
  10. Dec 27, 2017 #9


    Staff: Mentor

    There can be many equally valid mathematical expressions which all mean the same thing. That is largely what math is used for: determining many other formulas for the same thing. So if you wanted we could come with many more than just 2.
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