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Name ______________________________ Class ___________________ Date __________________
Skills Worksheet
Directed Reading A
Section: What Is Light?
1. Name two things that produce light.
The sun, bon fires and light bulbs produce light.
LIGHT: AN ELECTROMAGNETIC WAVE
_____ 2. What is light?
a. a type of matter
c. a type of energy
b. a type of sound wave
d. a type of water wave
3. How is light different from other kinds of waves?
Light does not require matter through which to travel. Other kinds of waves
must travel through matter.
4. A wave that consists of changing electric and magnetic fields and that can
travel through empty space is a(n) Electromagnetic Wave
5. Where do fields exist and what do they do?
Fields exist around certain objects and can exert a force on another object
without touching that object.
6. The electric and magnetic fields of an electromagnetic wave are perpendicular
to each other and to the direction of the wave’s motion.
7. Every charged object is surrounded by a(n) Electric Field.
8. An electric field pulls oppositely charged objects toward it and repels likecharged objects
9. Every magnet is surrounded by a(n) Magnetic field.
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
1
The Nature of Light
Name ______________________________ Class ___________________ Date __________________
Directed Reading A continued
10. Describe how an EM wave is produced?
An EM wave is produced by the vibration of an electrically charged particle.
When the particle vibrates, the electric field around it also vibrates. When the
electric field starts vibrating, a vibrating magnetic field is created.
11. From where does the energy carried by an EM wave come?
An EM wave carries energy released by the original vibration of a particle.
12. The transfer of energy as electromagnetic waves is called radiation.
THE SPEED OF LIGHT
13. Why do you see lightning before you hear the thunder that accompanies it?
Lightning is seen before thunder is heard because light travels much faster
than sound.
14. What is the speed of light in the near vacuum of space?
In the near vacuum of space, the speed of light is 300,000,000 m/s (or 300,000
km/s).
15. Calculate how long light takes to travel from Earth to the moon if the distance
between them is 384,000 km.
384,000 km/300,000 km/s;
time 5 1.28 s
LIGHT FROM THE SUN
16. How long does light take to travel from the sun to Earth?
8.3 min
17. The major source of energy on Earth are EM waves from the sun
18. Describe two ways in which the sun’s energy is used on Earth.
Plants use photosynthesis to store energy from the sun. Animals use and store
energy by eating plants or eating other animals that eat plants. Fossil fuels
store energy from the sun.
19. Why does only a small part of the total energy given off by the sun reach
Earth?
Most of the energy travels away in space
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
2
The Nature of Light