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Postby TGTS0907129» Nature of electric current

Explain the nature of electric current

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The flow of charge caused by an electric field may, in the case of a gas or liquid, consist of a flow of positive ions in the direction of the field or of negative ions or electrons opposite to that direction, or of both at once. In a metal the flow is known to consist largely of a moment of electrons opposite to the direction of field, electrons opposite to the direction of the field. A large number of electrons in a metal are relatively free to move about, with random thermal motions. In the absence of an electric field this motion produces no net flow of charge in any particular direction. Upon the application of an electric field to the metal, however, the velocities of the electrons moving opposite to the field are increased, and those in the direction to the field are decreased, causing a net the direction of the field are decreased, causing a net flow of charge. The electrons are repeated deflected or stopped by process associated with imperfections in the metallic crystals, impurities, and the thermal motions of the atoms,. Hence the flow is not an accelerated one but rather a drift or diffusion process. The average gift velocity is low- of the order of 0.1 mm/s in a typical case. However, changes in the flow rate are propagated with a speed approaching the speed of light. 

Some objects are classified as conductors of electricity, for example, metals, and other as nonconductors or insulators, such as glass or rubber. Conductors differ from insulators in the ease with which electrons leave their “parent” atoms and move through the conductor to constitute an electric current. There is a third type of material called semiconductor which have few electrons available for conduction. Silicon is an example of a semiconductor.

Benjamin Franklin recognized that a current could be through of as the motion of only one type of charge. Either a flow of positive charge to the right or of negative charge to the left could be called a current to the right. Any current direction is a convention, and the choice is arbitrary. But it is highly desirable that the choice be made so that a current directed toward a specific region, such as a capacitor plate, contributes to an increase of positive charge at that region, for the sake of consistency in setting up equations regarding charge, current, potential etc.

By TGTT23071246 on 10/14/2015 12:47:30 AM
TGTS0907129 on 10/14/2015 12:45:31 AM
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