Uma asked in Science & MathematicsPhysics · 1 decade ago

What is the velocity of Electric current in a circuit?

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  • 1 decade ago
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    Electric currents in solids typically flow very slowly. For example, in a copper wire of cross-section 0.5 mm2, carrying a current of 5 A, the drift velocity of the electrons is of the order of a millimetre per second.

    To take a different example, in the near-vacuum inside a cathode ray tube, the electrons travel in near-straight lines at about a tenth of the speed of light.

    In a 12 gauge copper wire carrying 10 amperes (typical for

    residential wiring), the drift speed is about 0.0002 m/s.

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    The formula to calculate the velocity is

    v = I / naQ where

    I is the electric current

    n is number of charged particles per unit volume (or charge carrier density)

    A is the cross-sectional area of the conductor

    v is the drift velocity, and

    Q is the charge on each particle.

    ========================================

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  • 3 years ago

    Speed Of Electric Current

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  • 1 decade ago

    The Speed of electricity refers to the relatively slow movement of free electrons or ions through a conductor in the presence of an electric field, also known as drift velocity. It is often confused with the propagation speed of an electromagnetic wave. It is the electromagnetic wave that usually conveys information (data), not the movement of electrons.

    Free electrons in a conductor vibrate randomly, but without the presence of an electric field there is no net velocity. When a DC voltage is applied the electrons will increase in speed proportional to the strength of the electric field. These speeds are on the order of millimeters per second. AC voltages cause no net movement; the electrons oscillate back and forth in response to the alternating electric field.

    In contrast, electromagnetic wave propagation is much faster, and depends on the dielectric constant of the material. In a vacuum the wave travels at the speed of light and almost that fast in air. Propagation speed is affected by insulation, such that in an unshielded copper conductor it is about 96% of the speed of light, while in a typical coaxial cable it is about 66% of the speed of light..

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  • 1 decade ago

    Are you talking about the electron drift speed or the speed at which the electric field propagates through the wire.

    The electron drift speed is extremely slow. In fact the haphazard thermal motion of electrons is much faster.

    See

    http://en.wikipedia.org/wiki/Electric_current#Drif...

    The electric field propagates at nearly the speed of light when information and energy is carried (obviously it cannot be greater). Engineers in the field of electronic communications call it the velocity factor, and it does depend on how well constructed the electric circuit wiring is.

    http://en.wikipedia.org/wiki/Wave_propagation_spee...

    The best example listed on this page is a velocity factor of 95%, corresponding to a propagation speed of 2.848*10^8 meters/second.

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  • Anonymous
    1 decade ago

    electricity flows by means of electrons, ... carrying a current of 5 A, the drift velocity of the electrons is of the ... When the circuit is solved, the circuit element currents may have positive or negative values

    Source(s): www.examville.com
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  • Ivette
    Lv 4
    4 years ago

    Electric current is neither a scalar nor a vector quantity. Electric current in a wire has both magnitude and direction but there is no meaning of triangle rule there. Also since it is gives the magnitude of charge flowing per unit time it has nothing to do with the direction.

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  • Anonymous
    6 years ago

    Drift velocity of electron is the speed of current.

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  • 6 years ago

    In case of pure copper conductors the velocity of electricity is almost 2.941*10^8 ms-1. which is almost 98.05% of velocity of light.

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  • 1 decade ago

    it is actually drift velocity at which electrons used to move in electric circuit

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  • 1 decade ago

    although the drift velocity of elecrons is nearly of the order 1mm/s but actually current travels at a speed of 3* 10^8 m/s that is the speed of light.

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