electric charge (redirected from Q (electricity))

electric charge: see charge.

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electric charge

Quantity of electricity that flows in electric currents or that accumulates on the surfaces of dissimilar nonmetallic substances that are rubbed together briskly. It occurs in discrete natural units, equal to the charge of an electron or proton. It cannot be created or destroyed. Charge can be positive or negative; one positive charge can combine with one negative charge, and the result is a net charge of zero. Two objects that have an excess of the same type of charge repel each other, while two objects with an excess of opposite charge attract each other. The unit of charge is the coulomb, which consists of 6.24 × 10¹⁸ natural units of electric charge.

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electric charge [i¦lek·trik ′chärj]

(electricity)

charge

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Electric charge

A basic property of elementary particles of matter. One does not define charge but takes it as a basic experimental quantity and defines other quantities in terms of it.

According to modern atomic theory, the nucleus of an atom has a positive charge because of its protons, and in the normal atom there are enough extranuclear electrons to balance the nuclear charge so that the normal atom as a whole is neutral. Generally, when the word charge is used in electricity, it means the unbalanced charge (excess or deficiency of electrons), so that physically there are enough “nonnormal” atoms to account for the positive charge on a “positively charged body” or enough unneutralized electrons to account for the negative charge on a “negatively charged body."

In line with this usage, the total charge q on a body is the total unbalanced charge possessed by the body. For example, if a sphere has a negative charge of 1 × 10^-10 coulomb, it has 6.24 × 10⁸ electrons more than are needed to neutralize its atoms. The coulomb is the unit of charge in the meter-kilogram-second (mks) system of units. See Coulomb's law, Electrical units and standards, Electrostatics