magnetism, its types, and its properties

2. MagnetismMagnetism
 In physics, magnetism is a force thatIn physics, magnetism is a force that
can attract (pull closer) or repel (pushcan attract (pull closer) or repel (push
away) objects that have a magneticaway) objects that have a magnetic
material like iron inside themmaterial like iron inside them
(magnetic objects).(magnetic objects).
 The power of attraction between twoThe power of attraction between two
elements is called magnetism.elements is called magnetism.
 In simpler words it is a property ofIn simpler words it is a property of
certain substances which pull closer orcertain substances which pull closer or
repel other objects.repel other objects.
 Magnetic materials are matter that isMagnetic materials are matter that is
attracted by magnets.attracted by magnets.
 It attracts opposite poles and repelIt attracts opposite poles and repel
same poles.same poles.

3. Magnetic and Non-MagneticMagnetic and Non-Magnetic
MaterialsMaterials
 Magnetic Material:Magnetic Material: Magnetic materials are matter that isMagnetic materials are matter that is
attracted by magnets.attracted by magnets. Magnetic materials can be made intoMagnetic materials can be made into
magnets.magnets.
 e. g:e. g: Iron, steel, nickel, cobalt and many alloys based on theseIron, steel, nickel, cobalt and many alloys based on these
metals.metals.
 Non-Magnetic Materials:Non-Magnetic Materials: Non-magnetic materials areNon-magnetic materials are
matter that is not attracted by magnets. Non-magnetic materialsmatter that is not attracted by magnets. Non-magnetic materials
cannot be made into magnets.cannot be made into magnets.
 e. g:e. g: Wood, glass, plastics and metals such as copper and brass.Wood, glass, plastics and metals such as copper and brass.

4. Types of MagnetismTypes of Magnetism
1.1. Permanent Magnet:Permanent Magnet:
 Permanent magnets arePermanent magnets are
those we are most familierthose we are most familier
with, such as the magnetswith, such as the magnets
hanging onto our refrigeratorhanging onto our refrigerator
doors.doors.
 They are permanent in theThey are permanent in the
sense that once they aresense that once they are
magnetized, they retain amagnetized, they retain a
level of magnetism.level of magnetism.

5. Temporary MagnetTemporary Magnet
• Temporary magnets areTemporary magnets are
those which act like athose which act like a
permanent magnet when theypermanent magnet when they
are within a strong magneticare within a strong magnetic
field, but lose theirfield, but lose their
magnetism when themagnetism when the
magnetic field disappears.magnetic field disappears.
 Examples would be paperclipsExamples would be paperclips
and nails and other soft ironand nails and other soft iron
items.items.

6. ElectromagnetismElectromagnetism
 Electricity and magnetism areElectricity and magnetism are
two aspects oftwo aspects of
electromagnetism.electromagnetism.
 Magnetism produced by anMagnetism produced by an
electric current, and electricelectric current, and electric
current produced by acurrent produced by a
changing magnetic field. Thechanging magnetic field. The
branch of physics that dealsbranch of physics that deals
with the interaction of electricwith the interaction of electric
and magnetic fields.and magnetic fields.

7. FerromagnetismFerromagnetism
 FerromagnetismFerromagnetism is the basic mechanism is the basic mechanism
by which certain materials (such as iron)by which certain materials (such as iron)
form permanent magnets, or are attractedform permanent magnets, or are attracted
to magnets.to magnets.
 Ferromagnetism is the strongest type: it isFerromagnetism is the strongest type: it is
the only one that typically creates forcesthe only one that typically creates forces
strong enough to be felt, and is responsiblestrong enough to be felt, and is responsible
for the common phenomena of magnetismfor the common phenomena of magnetism
in magnets encountered in daily life.in magnets encountered in daily life.
 Ferromagnetism is a kind of magnetism thatFerromagnetism is a kind of magnetism that
is associated with iron, cobalt, nickel, andis associated with iron, cobalt, nickel, and
some alloys or compounds containing one orsome alloys or compounds containing one or
more of these elements.more of these elements.

8. General Properties of MagnetismGeneral Properties of Magnetism
 All the magnets have two types of poles: north-seekingAll the magnets have two types of poles: north-seeking
poles or north poles and south-seeking poles or southpoles or north poles and south-seeking poles or south
poles.poles.
 The magnetic strength is the strongest at the poles of theThe magnetic strength is the strongest at the poles of the
magnet.magnet.
 When you freely suspend a bar magnet in a horizontalWhen you freely suspend a bar magnet in a horizontal
position, the magnetic field of the bar magnet willposition, the magnetic field of the bar magnet will
interact with the magnetic field of the Earth. This willinteract with the magnetic field of the Earth. This will
cause the bar magnet to come to rest in a north-southcause the bar magnet to come to rest in a north-south
direction, where the north pole of the magnet points todirection, where the north pole of the magnet points to
the north pole of the Earth.the north pole of the Earth.

9. Properties of MagnetsProperties of Magnets

Like poles repel and unlike poles attract. (just as likeLike poles repel and unlike poles attract. (just as like
charges repel and unlike chargescharges repel and unlike charges
attract).attract).
 Magnets attract magnetic materials such as iron, steel,Magnets attract magnetic materials such as iron, steel,
cobalt and nickel.cobalt and nickel.
 The stronger a magnet, the larger will be the attractive orThe stronger a magnet, the larger will be the attractive or
repulsive force between other magnets.repulsive force between other magnets.
 The closer together the two magnets are, the greater isThe closer together the two magnets are, the greater is
the magnetic force between them.the magnetic force between them.

10. InductionInduction
 When a magnet is passedWhen a magnet is passed
through a coil of wire, itthrough a coil of wire, it
produces an electric current .produces an electric current .
 The direction of the flow of theThe direction of the flow of the
current depends on thecurrent depends on the
direction on which the magnetdirection on which the magnet
moves.moves.
 In the above diagram, theIn the above diagram, the
current flow from right to leftcurrent flow from right to left
and in the bottom diagram, theand in the bottom diagram, the
current flows from left to right.current flows from left to right.

11. Magnetic Flux and Magnetic fieldMagnetic Flux and Magnetic field
 Magnetic Flux:Magnetic Flux:
A measure of the quantity of magnetism, being the totalA measure of the quantity of magnetism, being the total
number of magnetic linesnumber of magnetic lines
of force passing through specified area in a magnetic fielof force passing through specified area in a magnetic fiel
d.d.
 Magnetic Field:Magnetic Field: A region around a magnetic materialA region around a magnetic material
or a moving electric charge within which the force ofor a moving electric charge within which the force of
magnetism acts is called magnetic field.magnetism acts is called magnetic field.

12. Hall Effect and Flux DensityHall Effect and Flux Density
 Hall Effect:Hall Effect: The production of a potential differenceThe production of a potential difference
across a conductor carrying an electric current when aacross a conductor carrying an electric current when a
magnetic field is applied in a direction perpendicular tomagnetic field is applied in a direction perpendicular to
that of the current flow.that of the current flow.
 Flux Density:Flux Density: Flux DensityFlux Density (B)(B) is defined as the forceis defined as the force
acting per unit current per unit length on a wire placed atacting per unit current per unit length on a wire placed at
right angles to the magnetic field.right angles to the magnetic field.