Coulomb - Relation To Elementary Charge

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:

    “The proper study of mankind is man in his relation to his deity.”
    —D.H. (David Herbert)

    “The psychoanalysis of individual human beings, however, teaches us with quite special insistence that the god of each of them is formed in the likeness of his father, that his personal relation to God depends on his relation to his father in the flesh and oscillates and changes along with that relation, and that at bottom God is nothing other than an exalted father.”
    —Sigmund Freud (1856–1939)

    “Listen. We converse as we live—by repeating, by combining and recombining a few elements over and over again just as nature does when of elementary particles it builds a world.”
    —William Gass (b. 1924)

    “Carlyle must undoubtedly plead guilty to the charge of mannerism. He not only has his vein, but his peculiar manner of working it. He has a style which can be imitated, and sometimes is an imitator of himself.”
    —Henry David Thoreau (1817–1862)