### Table of Contents

# Elementary charge

Stan Zurek, Elementary charge, Encyclopedia Magnetica, http://www.e-magnetica.pl/doku.php/elementary_charge |

**Elementary charge** (** e**) - the smallest amount of electric charge having the value of:

**e = 1.602 176 634 × 10**coulomb.

^{−19}^{1)}

^{2)}. This value is a constant in our universe.

^{3)}

A **proton** has a positive charge of **+e**, and **electron** to the exactly opposite, negative value of **-e** (neutron has zero charge). The matching of the amount of the quantum of positive and negative charges is extremely precise to the highest experimental accuracy that can be attained, at the level of 1 part in 10^{20}. If this was not the case then matter would violently disintegrate.^{4)}^{5)}

The electric charges in antimatter are reversed, with positron (equivalent of electron) being positive, and antiproton negative. It is possible for positive and negative charges (e.g. electron and positron) to combine and annihilate, converting to other form of energy. It is also possible for two opposing charges to be produced in some sub-atomic interaction. But such interactions always occur in pairs of positive-negative charges, so that the law of charge conservation never violated.^{6)} For example, during radioactive decay it is possible for a positron (e+) to be emitted from a proton (e+), which then becomes a neutron so that the amount of electric charge remains constant.^{7)}

Electrically charged particles also exhibit intrinsic magnetic moment. Electron magnetic moment is especially strong and is responsible for the phenomenon of ferromagnetism.^{8)}

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### Fractional charges

Only such sub-atomic particles like quarks are thought to have electric electric charge in non-integer quantities e.g. -1/3 *e* or +2/3 *e*, but they only exists in configurations which add up to integer values of charge. For example, proton comprises three quarks (*up, up, down*), which add up to +1 *e*. Therefore, in any macroscopic application the charge is always quantised by the elementary amount of 1 e.^{9)}^{10)}

## See also

## References

^{1)}Bureau International des Poids et Mesures, The International System of Units (SI), 9th edition, 2019, {accessed 2021-04-10}

^{3)}Encyclopædia Britannica, Electric charge, {accessed 2020-10-25}

^{4), 6), 8), 9)}E.M. Purcell, D.J. Morin, Electricity and magnetism, 3rd edition, Cambridge University Press, 2013, ISBN 9781107014022

^{5)}David J. Griffiths, Introduction to electrodynamics, 4th ed., Pearson, Boston, 2013, ISBN 0321856562

^{10)}David Tong, Electromagnetism, University of Cambridge Part IB and Part II Mathematical Tripos, Lent Term, 2015, {accessed 2020-10-16}