Electron Theory- there are several theories of electrification which have been advanced to proove the phenomenon of electrification. (1) BENJAMIN FRANKLIN's One Fluid Theory- In the year 1749 Benjamin Franklin proposed that the electrification of the bodies is due to electric fluid which combines with them in different degrees. when the body is neutral it has a certain quantity of fluid. The body becomes positively charged if there is excess of electric fluid. The body becomes negatively charged if the quantity of electric fluid decreases than its normal quantity(which makes it neutral). thus,before rubbing, the ebonite rod is neutral and when its rubbed with fur, a certain amount of fluid passes from the rod to fur so that the rod becomes negatively charged and the fur becomes positively charged, but the total quantity of fluid remains the same. The theory emphasizes that there are only two states of Electricity and not two kinds of Electricity. (2)Symmer's Two-Fluid Theory-According to Symmer the electrification is due to two electric fluids :positive and negative.A neutral body possesses these fluids in equal quantities.when two bodies(ebonite and flannel) are rubbed, the negative fluid goes to one (to ebonite)and the positive fluid goes to the other(to flannel).
The theory undoubtedly proves that the two similar fluids repel each other and unlike fluids attract;and it also proves that there is simultaneous development of kind of electrification. (3)MODERN THEORY-The modern theory is known as " ELECTRON THEORY" .this theory not only explains about attraction , repultion and two kinds of electrification in electrostatics;but also gives clear conception of Voltage , resistance, Insulation, Induced Voltage and magnetism.