By convention, the charge
on an electron is taken to be negative; therefore charge on an electron is
written as –e and that on a proton as +e The fact that electric charge is always an integral multiple of e is termed
as quantisation of charge There are a large number of situations in physics
where certain physical quantities are quantised The quantisation of charge
was first suggested by the experimental laws of electrolysis discovered by
English experimentalist Faraday