Download Notes: Magnetism

Notes: Magnetism
Force of attraction or repulsion between various substances, especially those made of iron,
nickel and cobalt; it is due to the motion of electric charges"
Magnetic Field
What is it?
the area in which the
force of magnetism acts.
Unlike poles attract
Like poles repel
Illustration:
Earth’s magnetic field (2 facts) :
1. Protects us from solar wind
2. Makes the earth act like a big
bar magnet
Magnet Domain
What is it?
Magnets
A cluster of
atoms .
Explain why Magnetized
The domains are all
aligned
2 Types
Explain why not Magnetized
The domains are not
aligned
Permanent
Temporary
Magnets that
make their own
magnetic fields
Ex.
Bar magnets
Certain minerals
Ex.
Earth
1 way to magnetize an object
Sliding a magnet across
the object in one
direction to align the
domains.
3 ways to demagnetize an object
1. Hit it
2. Drop it
3. Heat it
Magnets that do
not make their
own magnetic
fields and lose
the field when it
disappears
Ex.
Electromagnets
Nails & Paper
Clips
Ex.
Electromagnet
What is needed to induce the
Magnetic force?
Electricity
Label the 3 main parts:
Motor
A machine that uses electric
energy to produce motion.
Changes electrical energy to
mechanical energy.
wire
Generator
A machine that uses motion to
create electric energy.
Changes mechanical energy to
electrical energy
Power
source
core
Notes: Transformers
Principle:
What does it do?
An
An electrical current
can create a magnetic
field
An electrical device
that changes the
voltage of AC current
to help control it.
2 types
Step- Up Transformers
Step-Down Transformers
Increases voltage but
decreases Amps.
decreases voltage but
increases Amps.
Primary coil has fewer
turns
Primary coil has more
turns
Primarily used? Power plants
Primarily used? At home
To send lots of energy safely
Takes lots of energy and
decrease the current
Label the Parts to a Transformer
( Input Volts, Output Volts, Primary Coil, Secondary Coil,
Iron Core, 8 coils, 24 coils )
Input V
Output V
Iron Core
Primary
Coil- 24
Secondary
Coil- 8
This is a Step-Down transformer
What does this mean?

The primary coil has 24 turns.

The secondary coil has 8 turns.

So, the secondary coil has 1/3 of the turns as the primary coil.

This means if the input voltage was 300 V, then the output
voltage = 100 V

The Voltage was increased/decreased

The Current was increased/decreased