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Nature of Electricity

    It is comparatively easy to discribe what electricity can do than to give simple and direct answer to the question:  what exactly is meant by electricity?. Electricity has become such a universal medium for transmission and utilization of energy that almost evey one familiar with its innumerable uses right from the earliest chilhood. Electric energy is variouly utilised as for lighting, transportation, communication, for operating electric furnace, elevator, and for driving various kinds of machine tools ect. It can easily stored and concentrated to produce extremely high temperature as in welding and electric furnaces, acr light and spark plugs etc.
   Turning back to the question regarding the nature of electricity, it maybe noted that ancient Greeks were the first to observe that when Amber,it is a yellow brown gum that hardens into hard stone-like material, is rubbed against a piece of silk cloth, it attracts light objects like small pieces of paper etc. The agency that endowed this attracting property to amber was given the name of electricity by Gilbert in 1600 A.D. the name electricity is derived from the word electron” which is the Greek name of amber. for more detail you can see the figure 1 below.

figure 2   

 To explain the few observed phenomena about electricity, Benjamin Franklin Advance, in 1749, what was called One fluid Theory of Electricity. According this theory, elecreicity was assumed to be sort of an invisible and intangible fluid which was associated with matter in different degrees. The normal state of matter (in which it exhibited no electrical properties) was assosiated with a centain definite amount of this fluid. Any disturbance of this assumed normal distribution of fluid was supposed to result in the body being either positively or negatively charged corresponding to an axcess or deficit of this normal amount fluid. This theoy was succesful in explaning the production of positive and negative electricity when two bodies are rubbed together. Becouse, according to this theoy, rubbing of two bodies together led an unequal redistribution of their fluids whose total sum was supposed to remain constant. One day which got more of this fluid become positively charged and the other which got less became negatively charged.
   It will be noted that this theory does not assume two types of fluid, but simply two state of electrification resulting from an excess or deficit of the same fluid. This theory, however, did not hold ground for long since it could not satisfactory explain many electrical phenomena including induction.
      In the year 1735, Dufay Advandce the Two Fluid Theory which was later modified and restated in a more satisfactory manner by Symmer in1759. According to this theory, two diffrent types of fluid resided simultaneously in matter corresponding to two states of electrification i.e, positive and negative. The type and degree of electrification was measured by the excess of one of fluid over the other. The normal non-electrical state of matter was assumed to be due to the presence of equal quantities of these two fluids which neutralized each other.
    This theory was succesfully for some time, but was later on, discarded becouse (1) it was base on the untenable assumption of two invisible fluid present in the matter, and (2) it was found inadequate to fully explain may of the facts about electricity discovered afterwards.


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