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Electric potential

  1. Jul 29, 2007 #1

    does the electric field establish an electric potential around a circuit or does the electric potential establish the electric field?

    also if i understand correctly when the charges arrive at the end of a circuit, the battery moves these charges against the electric field in order to give it electric potential energy within the field the same way if I pick up a box straight up into the air against the gravitational field to give it mgh energy?

  2. jcsd
  3. Jul 30, 2007 #2

    Meir Achuz

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    E and the potential are directly related. You can't have one without the together. Neither one can come first.
  4. Jul 30, 2007 #3


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    Actually the electric potential is just a trick that allows us to work with a single quantity (the potential) instead of three (the spatial components of the electric field). You can always derive one if you know the other, therefore, they are equivalent.

    In charging a battery work is done against the electric field by accumulating a lot of like charge in a relatively small area (which will leave the other end oppositely charged). In effect, charging a battery is like lifting the box you spoke about; when we connect the battery to a circuit the system tries to minimise the potential energy by letting the charges flow from high to low density (which is, by definition of the electric potential, the direction of the electric field) just like the box will fall down because it has a lower potential energy there (roughly said).
  5. Jul 30, 2007 #4
    mozdef :
    A) Talking about Circuits Theory:
    When you set up a circuit you use Voltage-sources.
    V-sources, by definition, force an electric potential from the + pole to the -pole. The electric field on each point of the circuit depends on the devices you connect to the V-source.
    A battery is similar to a V-source

    B) If you move a wire through a magnetic field it will appear an electric field of x Volts/meter. If the wire is 2 meters long from one end of the wire to the other end you will get 2x volts.
  6. Jul 31, 2007 #5
    thanks guys
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