Electromagnetism

1. EQ: How are electricity and
magnetism related and how does it
affect our every day life?

2. MAGNETISM
A material that has aligned domains
with repulsive and attractive forces
ELECTRICITY
The movement of electrons from one
place to another

3. ► Charged particles experience an electric force
when in an electric field regardless of
whether they are moving or not moving
►Electric field
► There is another force that charged particles
can experience even in the absence of an
electric field but only when they are motion
► A Magnetic Force
ELECTRICITY & MAGNETISM

4. Magnetic Forces
► This force is
► proportional to the charge q
► proportional to the speed v
► perpendicular to both v and B (magnetic field)
B
v
q
F





Given a charge q moving with a velocity v in a magnetic field, it is
found that there is a force on the charge
This can be summarized as

5. ELECTRICITY MAGNETISM
► How can you tell?
Compass needle moves when
near electrical current -
creating a magnetic field
Electric currents cause magnetism

6. ELECTROMAGNET
How to increase the strength of the
magnet
 More coils of wire= more current
 Increase voltage
 Add iron to the core
A temporary magnet made by wrapping a wire
coil carrying an electric current around an iron
core.

7. 1. Straight wire
2. Single loop
Increasing the strength of the
magnetic field
(1-weakest, 4 –strongest)
3. Solenoid - A
single wire wrapped
into a cylindrical
wire coil
4. Solenoid with
iron core

8. ►Electric motors are used in most household
appliances which convert electricity into
mechanical energy (motion).

9. How does an electric motor
work?

10. Go to the next slide 
How does an electric motor work?

11. Simple as that!! How a speaker works
https://www.youtube.com/watch?v=DMxn3CPLe-A
How does an electric motor work?

12. MAGNETISM  ELECTRICITY
► How can you tell?
Electromagnetic induction
moving a magnet in and out of a
coiled wire created an electrical
current without a battery
Moving magnet can generate electricity
https://www.youtube.com/watch?v=hajIIGHPeuU

13. Moving a loop of wire through a magnetic
field or moving a magnet through a loop of
wire produces an electric current.

14. A generator is used to convert mechanical
energy into electrical energy by
electromagnetic induction.

16. Dilbert

17. Direct current versus alternatingcurrent –
AC vs DC : What’s the difference?
Direct current is electrical current which comes from a
battery which supplies a constant flow of electricity in
one direction.
Alternating current is electrical current which comes from a
generator. As the electromagnet is rotated in the
permanent magnet the direction of the current
alternates once for every revolution.
You can see that the DC source is a battery – current
flows in one direction. The AC source is the generator
and the current alternates once for each revolution.

18. Maglev Trains
►Maglev trains are the new way to travel. It
uses both magnets and electricity to cause a
train to “levitate” above the track (and
reduce the resistance of friction).

19. Changing Voltage
► Transformers work by the ratio of coils
to change voltage:
 Changing magnetic field
strength: If you have more
coils on the output side
than the input side, then
you increase voltage. If
you have less coils on the
output side, then you
decrease voltage.

20. Superconductors
Electricity can flow through some materials, such as
metal very easily. Electrons do not flow as easily
through materials such as glass, wood or rubber.
When electricity flows, it has to overcome resistance.
At very low temperatures that resistance is
reduced. None of the electric energy converts to
heat, so a superconductor creates a very strong
magnetic field.

21. PLASMA
Plasma
► 4th state of matter
► Highly conductive of electricity
► Highly magnetic
► On Earth = Northern(Southern)lights
► On Sun causes
sun spots, flares, prominences &
Coronal Mass Ejections
(CME – where plasma escapes to earth)
Superheated matter where electrons are not
bound to nucleus; free electrons & ions

22. • Both can cause
each other
• Likes repel
• Opposites attract
SUMMARY OF E & M
ELECTRICITY
► Can be + or -
► Can flow (current)
► Can jump (static)
E = Electricity and M = Magnetism are related!!
MAGNETISM
► Can NOT have only
1 pole
► Can be Normal (N)
or Reversed (S) pole
► Can move through
field
► Causes sun spots,
flares, CME

23. Closing Task
►Differentiate between an
electromagnet and
electromagnetic induction. How
are both used in your every day
lives

24. ►An electric motor is a device which converts
electricity to mechanical energy.
► An electromagnet turns inside of a permanent
magnet. By changing the direction of the current,
the poles will keep switching between N and S, and
therefore cause the electromagnet to continually
rotate.
►Electric generators do just the opposite. They
convert mechanical energy into electricity.
► They do this through a process of electromagnetic
induction. This is where an electric current is
generated by manually varying a magnetic field.