magnetism
matter and
Magnetism : -
Some substances have the
property of attracting ferromagnetic substances
clike-iron ,
nickel and cobaltetc) towards them . This property is called
magnetism.
the
Those substance which have
property of magnetism are called
magnets .
Magnets are of two types.
I Natural magnet >
-
eg
. FezO4
2 Artificial magnet < e .
g.
solenoid
Bar-magnet : A bar
magnet is a
rectangular object with permanent magnetic properties.
Properties : -
I The bar
magnet has two poles similar to the positive and
negative charge
of an electric dipole
One pole is
designated as north and other as south pole.
When suspended these poles point approximately towards
~
the
freely ,
north and south poles.
geographic
.
3 Like poles repel each other and unlike poles attract each other .
4 The poles of a
magnet can never be separated.
5
Magnetic Length =
Ex Geometric
length Appron 84 % )
G Pole strength -Pole strength
: is a measure of strength of a magnetic pole.
the
It is defined as the force experienced by the pole per unit external
magnetic field strength .
SI unit : -Ambere-meter (Am)
Pole strength < cross-sectional area of bar
magnet .
N S N S
Area All
A
O O =
-
its then
re s e a
n If it is cut along length
⑧
u s e
strength
Pole
⑨ O
Im So,
=
, Magnetic field lines : -
I These are
imaginary curve .
C The
tangent to which at any point gives direction of magnetic field.
3 The
magnetic field lines of magnet cor solenoids from close-continuous looks.
↳ Outside the body of magnet ,
the direction of magnetic field lines are from
North pole to south pole
.
5 Two
magnetic field lines never intersect each other.
material
s
Magnetic field lines come out and
go into a
magnetic at
any
angle .
7 number of magnetic field lines per unit
crossing area.
-
Uniform magnetic field non-uniform non-uniform
field line due to bar magnet
A
· -
: u
Magnetic dipole moment of bar-magnet :
S N =>
-
M +M
⑧
I
K l 7
dipole moment-I Pole
strength I magnetic length
# mi =
SI .
Unit : -
Am2
Direction :-S to N
matter and
Magnetism : -
Some substances have the
property of attracting ferromagnetic substances
clike-iron ,
nickel and cobaltetc) towards them . This property is called
magnetism.
the
Those substance which have
property of magnetism are called
magnets .
Magnets are of two types.
I Natural magnet >
-
eg
. FezO4
2 Artificial magnet < e .
g.
solenoid
Bar-magnet : A bar
magnet is a
rectangular object with permanent magnetic properties.
Properties : -
I The bar
magnet has two poles similar to the positive and
negative charge
of an electric dipole
One pole is
designated as north and other as south pole.
When suspended these poles point approximately towards
~
the
freely ,
north and south poles.
geographic
.
3 Like poles repel each other and unlike poles attract each other .
4 The poles of a
magnet can never be separated.
5
Magnetic Length =
Ex Geometric
length Appron 84 % )
G Pole strength -Pole strength
: is a measure of strength of a magnetic pole.
the
It is defined as the force experienced by the pole per unit external
magnetic field strength .
SI unit : -Ambere-meter (Am)
Pole strength < cross-sectional area of bar
magnet .
N S N S
Area All
A
O O =
-
its then
re s e a
n If it is cut along length
⑧
u s e
strength
Pole
⑨ O
Im So,
=
, Magnetic field lines : -
I These are
imaginary curve .
C The
tangent to which at any point gives direction of magnetic field.
3 The
magnetic field lines of magnet cor solenoids from close-continuous looks.
↳ Outside the body of magnet ,
the direction of magnetic field lines are from
North pole to south pole
.
5 Two
magnetic field lines never intersect each other.
material
s
Magnetic field lines come out and
go into a
magnetic at
any
angle .
7 number of magnetic field lines per unit
crossing area.
-
Uniform magnetic field non-uniform non-uniform
field line due to bar magnet
A
· -
: u
Magnetic dipole moment of bar-magnet :
S N =>
-
M +M
⑧
I
K l 7
dipole moment-I Pole
strength I magnetic length
# mi =
SI .
Unit : -
Am2
Direction :-S to N
