Relation To Elementary Charge
The elementary charge, the charge of a proton (equivalently, the negative of the charge of an electron), is approximately 1.602176487(40)×10−19 C. In SI, the elementary charge in coulombs is an approximate value: no experiment can be infinitely accurate. However, in other unit systems, the elementary charge has an exact value by definition, and other charges are ultimately measured relative to the elementary charge. For example, in conventional electrical units, the values of the Josephson constant KJ and von Klitzing constant RK are exact defined values (written KJ-90 and RK-90), and it follows that the elementary charge is also an exact defined value in this unit system. Specifically, exactly. SI itself may someday change its definitions in a similar way. For example, one possible proposed redefinition is "the ampere...is such that the value of the elementary charge e (charge on a proton) is exactly 1.602176487×10−19 coulomb" This proposal is not yet accepted as part of the SI system: The SI definitions are unlikely to change until at least 2015.
Read more about this topic: Coulomb
Famous quotes containing the words relation to, relation, elementary and/or charge:
“You must realize that I was suffering from love and I knew him as intimately as I knew my own image in a mirror. In other words, I knew him only in relation to myself.”
—Angela Carter (1940–1992)
“There is a certain standard of grace and beauty which consists in a certain relation between our nature, such as it is, weak or strong, and the thing which pleases us. Whatever is formed according to this standard pleases us, be it house, song, discourse, verse, prose, woman, birds, rivers, trees, room, dress, and so on. Whatever is not made according to this standard displeases those who have good taste.”
—Blaise Pascal (1623–1662)
“When the Devil quotes Scriptures, it’s not, really, to deceive, but simply that the masses are so ignorant of theology that somebody has to teach them the elementary texts before he can seduce them.”
—Paul Goodman (1911–1972)
“One can only call that youth healthful which refuses to be reconciled old ways and which, foolishly or shrewdly, combats the old. This is nature’s charge and all progress hinges upon it.”
—Anton Pavlovich Chekhov (1860–1904)