Question

who introduced polarity of charge

Answer 1

Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. There are two types of electric charges.
positive & negative


"vitreous" electricity, the naming was natural. Eventually it was discovered that the truth was a mix of the two old theories, with two kinds of charge really existing but just one being easy to move and causing excess of lack. The nature of the negative charge, the "electrons", light discrete bodies that are part of the atoms that compose all matter, was discovered first, in 1897 by J. J. Thomson, with the nature of the positive charge, located in "protons" at the nuclei of atoms discovered some time after, between 1911 and 1920, by E. Rutherford. Only the electrons (and just some of them) are easy to transfer between bodies, and so Franklin and Watson committed an error in the notion of what is excess and what is lack that become permanent.