This is about electricity and magnetism, right? (Coulomb)? (electrons and protons)
One of my Physics textbook says this:
Note that 1 C is substantial amount of charge. In typical electrostatic experiments, where a rubber or glass rod is charged by friction, a net charge of the order of 10-6 C is obtained. In other words, only very small fraction of the total available charge is transferred between the rod and the rubbing material.
Basically, 1.0 x 10-6 C or 0.1 x 10-5 C will be the maximum net charge that can be obtained (by rubbing). So, this amount of charge (0.1 x 10-19 C = 1.0 x 10-20 C) is acceptable (to my knowledge).
10-6 = 1.0 x 10-6 (1 micro-coulomb)
Coulomb's law applies exactly only to point charges or particles.
From another Physics textbook that I have says this:
COULOMB AND YOU
By human standards, the coulomb is definitely a great deal of charge. We are accustomed to taking our charge in far smaller doses, usually in the form of sparks that carry much less than a micro-coulomb (1.0 x 10-6 C). Usually robbing will build up charge on an ordinary-size object with density of up to 10 nano-coulombs (1.0 x 10-9 C) per cm2, which is a practical limit beyond which there will tend to be discharging into the air.
(0.1 x 10-19 C = 1.0 x 10-20 C). Compare that to 0.1 x 10-5 C or 1.0 x 10-6 C. Much and much smaller. Right?
I hope these concepts from my textbooks helps.