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Chapter Review
Electromagnetic waves transfer energy
through radiation.
CONTENT REVIEW
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KEY CONCEPTS SUMMARY
1
Electromagnetic waves have unique traits.
• Electromagnetic (EM) waves
are made of vibrating electric
and magnetic fields.
• EM waves travel at the speed
of light through a vacuum.
• EM waves transfer energy and
can interact with matter.
2
Electromagnetic waves have many uses.
• EM waves are grouped by
frequency on the EM spectrum.
• The EM spectrum is divided into
radio waves, microwaves, infrared
light, visible light, ultraviolet light,
x-rays, and gamma rays.
3
The Sun is the source of most visible light.
• Most visible light in the environment
comes from the Sun.
• Many living organisms produce
visible light for their own use.
• Humans produce visible light
artificially.
4
Light waves interact with materials.
• Reflection, transmission, and absorption affect what
light we see.
• Light can be scattered and polarized.
• Visible light is made up of many wavelengths.
• The primary colors are red, blue, and green.
• The primary pigments are yellow, cyan, and magenta.
582 Unit 4: Waves, Sound, and Light
VOCABULARY
electromagnetic
wave p. 553
radiation p. 555
VOCABULARY
EM spectrum p. 560
radio waves p. 562
microwaves p. 563
visible light p. 564
infrared light p. 564
ultraviolet light p. 565
x-rays p. 566
gamma rays p. 566
VOCABULARY
incandescence p. 569
luminescence p. 569
bioluminescence
p. 569
fluorescence p. 571
VOCABULARY
transmission p. 573
absorption p. 573
scattering p. 575
polarization p. 576
prism p. 577
primary colors p. 578
primary pigments
p. 579
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Reviewing Vocabulary
Make a four-square diagram for each of the
listed terms. Write the term in the center.
Define the term in one square. Write characteristics, examples, and nonexamples in other
squares. A sample is shown below.
A: Definition
disturbance in electric
and magnetic fields
B: Characteristics
doesn’t need
material medium
ELECTROMAGNETIC
WAVE
C: Examples
radio waves
microwaves
1.
2.
3.
4.
5.
gamma rays
infrared light
transmission
absorption
pigment
D: Nonexamples
water wave
sound wave
6. radiation
7. bioluminescence
8. EM spectrum
9. incandescence
10. polarization
Reviewing Key Concepts
Multiple Choice Choose the letter of the
best answer.
11. An electromagnetic wave is a disturbance that
transfers energy through a field. In this sense,
a disturbance is the same as a
a. confusion
c. vibration
b. magnification
d. conflict
12. Unlike mechanical waves, EM waves can travel
through
a. a vacuum
c. the ground
b. water
d. air
13. A light year is a measure of
a. time
c. speed
b. distance
d. wavelength
14. The Sun and a light bulb both produce light
through
a. bioluminescence c. luminescence
b. incandescence
d. polarization
15. Which of the following types of light bulb converts ultraviolet waves into visible light waves?
a. incandescent
c. halogen
b. fluorescent
d. tungsten
16. An object seen through translucent material
appears less clear than one seen through transparent material because the translucent material
a. transmits none of the light coming from
the object
b. reflects all the light coming from the object
c. transmits all the light coming from the object
d. diffuses some light coming from the object
17. An object appears red because it
a. reflects light waves of all colors
b. reflects light waves of red
c. absorbs light waves of red
d. transmits light waves of all colors
18. Primary colors of light can combine to make
a. black light
c. primary pigments
b. white light
d. ultraviolet light
Short Answer Write a short answer to
each question.
19. What vibrates in an EM wave?
20. How can EM waves be used to measure
distance?
21. Describe how microwaves are used in
communications.
22. What two properties of an EM wave change as
you move from one part of the EM spectrum
to another?
23. How does visible light differ from other EM
waves? How is it similar?
24. Explain briefly how an incandescent light
bulb works.
Chapter 17: Electromagnetic Waves 583
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Thinking Critically
The diagram below shows how far different
wavelengths of visible light penetrate into
ocean water. Use information from this diagram
to answer the next three questions.
25. OBSERVE An EM wave can interact with a
material in different ways. Which type of
interaction keeps some light waves from
reaching the ocean floor?
26. PREDICT How would violet light behave in the
same water? Think of where violet is on the
color spectrum.
32. IDENTIFY CAUSE AND EFFECT Liquid crystal displays like the ones used in some calculators
work by polarizing light. Describe how two
polarizing filters could cause the numbers on
the display panel to appear black.
33. COMPARE AND CONTRAST In what way would
a sieve be a good model for a polarizing light
filter? In what ways would it not be?
34. CONTRAST In what ways is a fluorescent
bulb more efficient than incandescent and
halogen bulbs?
35. PREDICT What color will a white object appear
to be if you look at it through a blue filter?
27. SYNTHESIZE How is the apparent color of
objects near the ocean floor affected by the
interactions shown in the diagram?
36. ANALYZE Return to the question on page 550.
Answer the question again, using what you
have learned in the chapter.
37. SUMMARIZE Write a summary of this chapter.
Use the Big Idea statement from page 550
as the title for your summary. Use the Key
Concepts listed on page 550 as the topic
sentences for each paragraph. Provide an
example for each key concept.
38. ANALYZE Describe all of the EM wave behaviors
and interactions that occur when a radiator
warms a kitten.
28. ANALYZE Under what circumstances can an
EM wave begin to convert some of its electromagnetic energy into other forms of energy?
29. ANALYZE What two things must be true about
the light source and the material of an object
for you to see an object as red?
30. PREDICT If you shine a blue light on a white
object, what color will the object appear to
be? What color light would you need to add
to make the white object appear white?
31. APPLY Why might incandescent lighting
become less common in the future? Explain
your reasoning.
584 Unit 4: Waves, Sound, and Light
Check your schedule for your unit project. How
are you doing? Be sure that you’ve placed data or
notes from your research in your project folder.
Page 4 of 4
For practice on your
state test, go to . . .
Standardized Test Practice
TEST PRACTICE
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Interpreting Diagrams
The diagram below shows part of the electromagnetic (EM) spectrum.
The lower band shows frequency in hertz. The upper band shows part of
the spectrum used by different technologies.
CB
TV
FM
Radio Ch. 2–6 Radio
AM
Radio
105 Hz
106 Hz
Use the diagram to answer the following questions.
1. Which of the technologies listed below
uses the highest frequencies?
a. AM radio
b. CB radio
c. FM radio
d. TV channels 2–6
2. If you were receiving a signal at a frequency of
nearly 109 Hz, what would you be using?
a.
b.
c.
d.
a CB radio
an AM radio
an FM radio
a cell phone
Extended Response
Answer the two questions below in detail. Include
some of the terms from the word box. Underline
each term you use in your answer.
5. What are the similarities and differences between
mechanical waves and electromagnetic waves?
107 Hz
TV
Ch. 7–13
108 Hz
Cell
Phones
109 Hz
3. A television station broadcasts its video signal at
106 Hz and its audio signal at 108 Hz. To receive
the broadcasts, your television would need to use
the technologies of
a. both AM and FM radio
b. both CB and AM radio
c. both CB and FM radio
d. both CB radio and cell phone transmissions
4. Signals with similar frequencies sometimes interfere
with each other. For this reason, you might expect
interference in which of the following?
a. lower television channels from cell phones
b. upper television channels from FM radio
c. lower television channels from FM radio
d. upper television channels from cell phones
frequency
field
energy
medium
interaction
vacuum
6. What are some advantages and disadvantages of
different types of artificial lighting?
Chapter 17: Electromagnetic Waves 585