Name ______________________________ Class ___________________ Date __________________
Skills Worksheet
Directed Reading A
Section: The Electromagnetic Spectrum
1. What kind of light can a bee see that you cannot see?
A bee can see ultraviolet light.
2. In what way is visible light similar to ultraviolet light?
Both visible light and ultraviolet light are kinds of electromagnetic waves
CHARACTERISTICS OF EM WAVES
3. How is the speed of a wave determined? The speed of a wave is determined by
multiplying its wavelength by its frequency.
4. The entire range of EM waves is called the electromagnetic spectrum
5. Name and arrange the seven kinds of EM waves in order from long
wavelength to short wavelength.
From the longest to the shortest wavelength, the EM waves are radio waves,
microwaves, infrared waves, visible light, ultraviolet, X rays, and gamma rays.
RADIO WAVES
6. Waves used for broadcasting radio signals are called radio waves
7. Describe how radio signals are broadcast?
A radio station converts sound into an electric current. The current produces
radio waves that are sent out in all directions by the antenna. A radio receives
radio waves and then converts them into an electric current, which then is
converted into sound.
8. Changing the amplitude or frequency of waves is called modulation.
9. Which type of radio waves—AM waves or FM waves—can travel a longer
distance and why? AM waves can travel farther because they can bounce off
the atmosphere.
10. Why does music broadcast from FM stations sound better than music
broadcast from AM stations? FM waves are less affected by electrical noise,
so the sound quality is better
11. Which kind of radio waves are used by television stations to carry sound?
Television stations use frequency-modulated (FM) waves to carry sound
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Science and Technology
4
The Nature of Light
Name ______________________________ Class ___________________ Date __________________
12. Which kind of radio waves are used by television stations to carry pictures?
Television stations use amplitude-modulated (AM) waves to carry pictures.
13. How are cable television signals sent to televisions in homes? Cable television
signals are transmitted to artificial satellites orbiting Earth. The waves are
amplified and relayed back to ground antennae. They then travel through
cables to home televisions.
MICROWAVES
14. In what way are the wavelengths and frequencies of microwaves different
from radio waves? Microwaves have shorter wavelengths and higher
frequencies than radio waves
15. Name three ways microwaves are used. Microwaves are used to cook food, to
send information over long distances,
16. In a microwave oven, the microwaves are created by a device called a(n)
magnetron, which accelerates charged particles.
17. What do the letters in radar stand for? The letters stand for radio detection and
ranging.
18. In addition to checking the speed of a car, what are two other ways radar is
used? Radar is used to watch the movement of airplanes and to help ships
navigate at night.
INFRARED WAVES
19. In what way are the wavelengths and frequencies of infrared waves different
from the wavelengths and frequencies of microwaves? Infrared waves have
shorter wavelengths and higher frequencies than microwaves.
20. How are infrared waves able to make you feel warm? Skin absorbs infrared
waves that strike the body. The energy of the waves causes the particles in the
skin to vibrate.
21. Name three sources of infrared waves. Three sources of infrared waves are
buildings, tires, and people.
22. On What does the amount of infrared waves that an object gives off depend? It
depends on an object’s temperature
VISIBLE LIGHT
23. The very narrow range of wavelengths and frequencies in the electromagnetic
spectrum that humans can see is visible light
24. In what ways are the wavelengths of visible light different from infrared
waves? Visible light waves have shorter wavelengths and higher frequencies
than infrared waves
25. The visible light of all wavelengths combined is white light
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Science and Technology
5
The Nature of Light
Name ______________________________ Class ___________________ Date __________________
26. What color are the longest wavelengths of visible light? Red Light
27. What color are the shortest wavelengths of visible light? Violet
28. The range of colors of visible light is called the visible portion of the EM
spectrum
29. What does each letter in the imaginary name ROY G. Bi V stand for? They
stand for red, orange, yellow, green, blue, indigo, and violet
30. What can cause all the colors of visible light to be seen in a rainbow? Water
droplets separate white light into visible light of different lengths.
ULTRAVIOLET LIGHT
31. In what way are the wavelengths and frequencies of ultraviolet light different
from the wavelengths and frequencies of visible light? Ultraviolet light waves
have shorter wavelengths and higher frequencies than visible light.
32. Describe four bad effects of ultraviolet light. Too much ultraviolet light can
cause sunburn, skin cancer, wrinkles, and damage to the eyes.
33. What are two ways you can protect yourself against ultraviolet light? You can
use sunscreen with a high SPF and wear sunglasses.
34. Describe two good effects of ultraviolet light. Ultraviolet waves are used to
kill bacteria on food and surgical cells, and skin cells that have been exposed
to ultraviolet light produce vitamin D.
X RAYS AND GAMMA RAYS
35. Which EM waves have some of the shortest wavelengths and highest
frequencies? X rays and gamma rays have the shortest wavelengths and
highest frequencies.
36. What is one use of X rays in the medical field? X rays are used to take pictures
of bones.
37. What can happen from too much exposure to X rays? Too much exposure to X
rays can damage or kill living cells
38. How are patients protected from exposure to X rays? Special aprons lined with
lead protect patients from too much exposure to X rays.
39. How are gamma rays used to treat cancer? Gamma rays are focused on tumors
inside the body to kill cancer cells.
40. What do gamma rays kill in food? harmful bacteria
Original content Copyright © by Holt, Rinehart and Winston. Additions and changes to the original content are the responsibility of the instructor.
Holt Science and Technology
6
The Nature of Light