Download Magnetism - Physics: 1(AE) 2(B,D)

Magnetism
What are magnets?
• A magnetic field is created around any
________________________________.
What is charged that is moving
within an atom?
• _______________ (e-)
• The atoms within most
materials have paired up
electrons spinning in
opposite directions so
the magnetic field that is
created by one is
cancelled out by the
other.
• Some materials like
iron, nickel, and
colbalt have a
single electron or
pair of electrons
that spin in the
same direction
creating a magnetic
field or a small
atomic magnet.
The atomic sized magnets line up to create
domains within the material.
The individual domains _______ to form a magnet.
A magnet has two ends called poles
(______________), where the magnetic
force is the strongest.
• No matter how
many times a
magnet is broken,
_______________
always has a north
pole and a south
pole.
• There is no such
thing as a
monopole.
A ______________________ exists around
a magnet or any moving charged object.
Magnetic fields are like electric fields or
gravitational fields in that they allow
magnets to interact without touching.
Imaginary lines that map out the magnetic
field around a magnet are known as
________________________ or
________________________________.
The direction of the magnetic field is
determined by using a compass.
___________________________________
___________________________________
Rules for drawing magnetic field lines:
1. Magnetic field lines always go from the _____________
to the _____________ (outside a magnet).
Bar Magnet
Horseshoe Magnet
Rules for drawing magnetic field lines:
2. Magnetic field lines are _________________ and never
cross or intersect.
Rules for drawing magnetic field lines:
3. Where the magnetic field lines are closer the magnetic
field is ____________________ .
Draw magnetic flux lines around
the magnets below:
S
S
N
N
S
N
N
S
Magnetism
• Magnetism is
the force of
attraction or
repulsion
between
magnetic poles.
Magnetic Field around the Earth
…Electromagnet
An electromagnet is a type of magnet whose
magnetic field is produced by the
____________________________. The magnetic field
disappears when the current ceases.
An electromagnet is most commonly made by coiling wire
around a piece of iron. This electromagnet is called a
solenoid. The shape of the magnetic field is the same as
a bar magnet.
As electrons move through the coil of wire, the magnetic field of one electron
adds to the field of any others moving in the same direction.
Factors affecting the magnetic field of a solenoid:
1. The magnetic field around a solenoid is directly
related to the ___________ through the coil.
Factors affecting the magnetic field of a solenoid:
2. The magnetic field around a solenoid is directly
related to the ______________ or coils around
the solenoid.
Factors affecting the magnetic field of a solenoid:
3. The magnetic field around a solenoid is directly
related to the ____________ around which the
wire is coiled. The soft iron is more permeable to
the magnetic field than the air is.
This is how Niagara Falls was used to
produce electricity…
Water flow is used to turn a
turbine through a magnetic field
inducing a potential difference and
producing electrical current.
This is how an electric motor works…
An electric motor utilizes the
property of electromagnetic
induction to convert electricity
into mechanical energy to make
things move. The conductor itself,
a coiled wire, will move to oppose
the magnetic field. Just when it
gets into position the current is
reversed, and the coil spins round
and round and round full of
mechanical energy.
A Generator…
A generator is simply the same
process in reverse, converting
mechanical energy into electricity.
Almost all of the electrical energy
we use in our daily lives is
supplied by electric generators.