MadSci Network: Physics |
By definition, current is charge in motion. The usual mechanism is electrons moving, but any charged particle (ions, "holes") qualifies. A graph of current versus time can describe the phenomenon. A lightning strike may have 10,000 amperes lasting for 2/10ths of a second. If the current were constant over the 0.2 second, a total of 2,000 coulombs will have been transferred. "Static" electricity occurs when voltage is built up by some mechanism that creates an excess of electrons in one place relative to another. It is important not to confuse the electric pressure -- voltage difference -- with the current -- charge flow. Current, when it happens, can relieve charge imbalance. Because static electricity occurs on surfaces insulated from any potent source of charge, the current (amperage) associated with a discharge will be of short duration, but it may be high as in lightning, or low as with charge imbalance leaking through the tires to the wet ground on a landed airplane. So it's only when the charge imbalance is being neutralized does current exist. If the electric path is easy (conductive) the current will be high for a short time. If it's difficult (relatively nonconductive) the current will be low, but for a long time. Try Bill Beaty's site at Beaty's site He's done a lot on static electricity and is a clear explainer on the subject. Larry Skarin
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