
29-1
Magnetic elds are typically conceptualized with so-called ux lines or lines of force. When such ux
li
nes
en
counter
an
y
so
rt
of ma
tter,
an in
teraction
ta
kes
pl
ace
in wh
ich
th
e
nu
mber
of u
x
li
nes
is ei
ther
in
creased
or de
creased
. e or
iginal
ma
gnetic
e
ld
th
erefore
be
comes
am
plied
or di
minished
in th
e
bo
dy
of ma
tter
as a re
sult
of th
e
in
teraction
. i
s
is tr
ue
wh
ether
th
e
ma
tter
is a ty
pical
“m
agnetic”
ma
te-
rial,
s
uch
a
s
i
ron
o
r
n
ickel,
o
r
a s
o-called
“
nonmagnetic”
m
aterial,
s
uch
a
s
c
opper
o
r
a
ir
.
e ma
gnetic permeability
of a su
bstance
is a nu
merical
de
scription
of th
e
ex
tent
to wh
ich
th
at
su
b-
stance interacts with an applied magnetic ...