Charge, Bound.
A charge of electricity borne by the surface of a body so situated with
reference to another oppositely charged body, that the charge is
imperceptible to ordinary test, will not affect an electroscope nor
leave the surface if the latter is connected to the earth. To discharge
such a body it must be connected to its complimentarily charged body.
The bound charge was formerly called dissimulated or latent electricity.
(See Charge, Free.)
The charge or portion of a charge of a surface which is neutralized
inductively by a neighboring charge of opposite kind. The degree of
neutralization or of binding will depend on the distance of the two
charged surfaces from one another and on the electro-static nature of
the medium intervening, which must of necessity be a dielectric. A
charge not so held or neutralized is termed a free charge. Thus a
surface may be charged and by the approach of a surface less highly
charged may have part of its charge bound. Then if connected to earth.
it will part with its unbound or free charge, but will retain the other
until the binding surface is removed, or until the electricity of such
surface is itself bound, or discharged, or until connection is made
between the two surfaces. Thus a body may have both a bound and a free
charge at the same time.
Charge, Density of.
The relative quantity of electricity upon a given surface. Thus a
charged surface may have an evenly distributed charge or one of even
density, or an unevenly distributed charge or one of uneven density. In
a thunderstorm the earth has a denser charge under the clouds than
elsewhere.
Synonym--Electrical Density.
Charge, Dissipation of.
As every body known conducts electricity, it is impossible so to
insulate a surface that it will not lose its charge by leakage. An
absolute vacuum might answer, and Crookes in a high vacuum has retained
a charge against dissipation for years. The gradual loss is termed as
above.
Charge, Distribution of.
The relation of densities of charge on different parts of a charged
body. On a spherical conductor the charge is normally of even
distribution; on other conductors it is unevenly distributed, being of
greatest density at points, edges, and parts of smallest radius of
curvature. Even distribution can also be disturbed by local induction,
due to the presence of oppositely charged bodies.