1. I. Characteristics of Magnets
Ch Magnetism
I. Characteristics of Magnets
Magnetism
Magnetic poles
Magnetic field
Magnetic domain 1

2. A. Magnetism
Magnetism
force of attraction or repulsion between unlike or like poles
due to the arrangement of electrons
closely related to electricity

3. B. Magnetic Poles Magnetic Poles like poles repel unlike poles attract
a broken magnet creates new poles

4. C. Magnetic Field Magnetic Field
area around a magnet where magnetic forces act
field lines show direction of field (NS)

5. D. Magnetic Domain Magnetic Domain
groups of atoms with aligned magnetic poles
domain
in a magnetized object, domains are all aligned

6. II. Uses of Magnetic Fields Electromagnet Speaker Motor
Ch Magnetism
II. Uses of Magnetic Fields
Electromagnet
Speaker
Motor 1

7. A. Electromagnet Electromagnet
strong, temporary magnet formed when current is passed through a coil of wire surrounding an iron core
acts like a bar magnet when current is on

8. B. Speaker Speaker electrical energy  mechanical energy
wire coil moves back & forth as its magnetic field interacts with the field of a fixed magnet
forced vibration causes the cone to move  sound

9. C. Motor Motor electrical energy  mechanical energy
electromagnet rotates between the poles of a fixed magnet
commutator reverses the poles of the e’magnet

10. brushes & wires to battery
C. Motor
assembled motor
armature & commutator
field magnet
brushes & wires to battery

11. III. Producing Electric Current
Ch Magnetism
III. Producing Electric Current
Electromagnetic Induction
Electric Generator
DC & AC
Transformer 1

12. A. Electromagnetic Induction
producing a current by moving a wire through a magnetic field
some microphones work just like mini-speakers in reverse
sound waves cause coil to move  current
Dynamic Microphone
Coil

13. B. Electric Generator Electric Generator
mechanical energy  electrical energy
armature is rotated between magnet poles
magnetic field induces a current in the wire coil
GENERATOR
MOTOR

14. B. Electric Generator Hydroelectric Dam
PE of lake water is converted to KE
mechanical KE turns the generator shaft which creates electrical energy

15. C. DC & AC Direct Current (DC) current flows in one direction
dry cells
Alternating Current (AC)
current reverses its direction at regular intervals
electrical outlets

16. D. Transformer Transformer increases or decreases AC voltage
primary coil AC produces a magnetic field that induces AC in the secondary coil
voltage ratio = ratio of turns in each coil

17. D. Transformer Step-up Transformer Step-down Transformer
increases the voltage
more turns
power plants
Step-down Transformer
decreases the voltage
fewer turns
household appliances (hairdryers, etc.)

18. I. Electromagnetic Radiation
Ch Light
I. Electromagnetic Radiation
EM Radiation
EM Spectrum
Types of EM Radiation

19. A. EM Radiation Electromagnetic Radiation
transverse waves produced by the motion of electrically charged particles
does not require a medium
speed in a vacuum = 300,000 km/s
electric and magnetic components are perpendicular

20. A. EM Radiation Photons tiny, particle-like bundles of radiation
absorbed and released by electrons
energy increases with wave frequency

21. B. EM Spectrum
long 
low f
low energy
short 
high f
high energy

22. C. Types of EM Radiation
Radiowaves
lowest energy EM radiation

23. C. Types of EM Radiation Radiowaves FM - frequency modulation
AM - amplitude modulation
Microwaves
penetrate food and vibrate water & fat molecules to produce thermal energy

24. C. Types of EM Radiation Infrared Radiation (IR)
slightly lower energy than visible light
can raise the thermal energy of objects
thermogram - image made by detecting IR radiation

25. C. Types of EM Radiation Visible Light
small part of the spectrum we can see
ROY G. BIV - colors in order of increasing energy R O Y G. B I V
red
orange
yellow
green
blue
indigo
violet

26. C. Types of EM Radiation Ultraviolet Radiation (UV)
slightly higher energy than visible light
Types:
UVA - tanning, wrinkles
UVB - sunburn, cancer
UVC - most harmful, sterilization

27. C. Types of EM Radiation Ultraviolet Radiation (UV)
Ozone layer depletion = UV exposure!

28. C. Types of EM Radiation X rays higher energy than UV
can penetrate soft tissue, but not bones

29. C. Types of EM Radiation Gamma rays highest energy EM radiation
emitted by radioactive atoms
used to kill cancerous cells
Radiation treatment using radioactive cobalt-60.