The coefficient of magnetic induction varies with the material of the
induced mass, and varies with the intensity of the magnetizing force.
This variation is due to the fact that as the induced magnetism in a
body increases, the magnetizing force required to maintain such
induction, increases in a more rapid ratio. The coefficient of magnetic
induction is the same as magnetic permeability, and in a certain sense
is the analogue of conductivity. It is also termed the multiplying power
of the body or core magnetized. It is the coefficient of induced
magnetization (see Magnetization, Coefficient of Induced) referred to a
mass of matter. For diamagnetic bodies the coefficient has a negative
sign; for paramagnetic bodies it has a positive sign.
Synonyms--Permeability--Multiplying Power--Magnetic Inductive Capacity.
Magnetic Induction, Dynamic.
The induction produced by a magnetic field which moves with respect to a
body, or where the body if moving moves at a different rate, or where
the body moves and the field is stationary. In the case where both move,
part of the induction may be dynamic and part static. (See Magnetic
Induction, Static.)
Magnetic Induction, Static.
Magnetic induction produced by a stationary field acting upon a
stationary body.
Magnetic Induction, Tube of.
An approximate cylinder or frustrum of a cone whose sides are formed of
lines of magnetic induction. (See Magnetic Induction, Lines of.) The
term tube is very curiously applied in this case, because the element or
portion of a magnetic field thus designated is in no sense hollow or
tubular.
Magnetic Inertia.
A sensible time is required to magnetize iron, or for it to part with
its magnetism, however soft it may be. This is due to its magnetic
inertia and is termed the lag. Permanent or residual magnetism is a
phase of it. It is analogous to self-induction of an electric circuit,
or to the residual capacity of a dielectric.
Magnetic Insulation.
Only approximate insulation of magnetism is possible. There is no
perfect insulator. The best ones are only 10,000 times less permeable
than iron. Hence lines of force find their way through air and all other
substance, being simply crowded together more in paths of iron or other
paramagnetic substance.