Electromagnetic Waves and Light

TEKS 8.8A

Electromagnetic Waves

KEY IDEAS

• What are light waves?
• How does light behave?
• What is the electromagnetic spectrum?

Words to Know

reflection

refraction

visible light

electromagnetic

spectrum

infrared

microwaves

radio waves

ultraviolet

X-rays

gamma rays

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Copyright © Savvas Learning Company LLC. All Rights Reserved. Savvas is not responsible for any modifications made by end users to the content posted in its original format.

What are light waves?

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What are light waves? continued

Light waves travel as electromagnetic disturbances. Light
waves do not need a medium to travel, so they can travel
through empty space. They travel at about 300,000
kilometers per second.

Multiple Choice

Which wave has the greatest amplitude?

• The blue wave
• The red wave

Multiple Choice

Light __ travel through a vacuum.

• can

• cannot

Multiple Choice

Light must travel through a vacuum.

• YES

• NO

Multiple Choice

Light is most like a __.

• particle

• wave

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How does light behave?

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Describe Electromagnetic Waves Answers

Identify Enter the correct words in the blanks.

Word bank

Waves are repeating disturbances. Light

waves travel as repeating

electric

and

magnetic

disturbances.

Light waves don’t need a medium to travel.

Unlike sound waves, light can travel through

space

. Light can be modeled as a

transverse wave because the disturbances

are perpendicular

to the direction of travel.

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How does light behave? continued

Straight lines, called rays, are
used to show the direction light
travels. Light can be reflected
and refracted. Reflection is when
light bounces off a material.

Refraction is when the direction
light travels bends as it passes
from one material to another.
How much light bends depends
on its wavelength.
The colors you see after light
is refracted by a prism are
components of visible light.

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What is the electromagnetic spectrum? 1

continued

The electromagneticspectrum is the complete range of
electromagnetic waves placed in order of increasing
frequency. The visible spectrum is just a small part of the
electromagnetic spectrum.

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What is the electromagnetic spectrum? 1

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What is the electromagnetic spectrum? 2

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What is the electromagnetic spectrum? 2

continued

Infrared (IR) is just below visible light on the EM spectrum.
It has greater wavelengths and lower frequencies.
Microwaves have even longer wavelengths, from 1 mm
to 30 cm. Radio waves have the lowest frequencies and
greatest wavelengths of all EM waves.

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What is the electromagnetic spectrum? 3

Multiple Choice

All waves carry

• energy
• light 
• matter
• particles

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What is the electromagnetic spectrum? 3

continued

Ultraviolet (UV) light is just above visible light on the EM
spectrum. It has shorter wavelengths and higher frequencies.
X-rays carry a great deal of energy and have high
frequencies. Gamma rayshave the highest frequencies and
shortest wavelengths of all EM waves.

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Types of EM Radiation

True or False Check which statements about electromagnetic
(EM) waves are false.

1.

Infrared waves have a higher frequency than
visible light.

2.

Gamma rays have the highest frequency and
shortest wavelength.

3.

Radio waves have a longer wavelength than
microwaves.

4.

Ultraviolet waves have a shorter wavelength
than X-rays.

5.

Most of the EM spectrum is visible light, so it
can be seen by humans.

Multiple Choice

What property of light makes this pencil appear to be bent or broken?

• Reflection
• Refraction
• Diffraction
• Absorption

Multiple Choice

The top of the wave

• Crest

• Compression

• Rarefaction

• Trough

Multiple Choice

region in a longitudinal wave where the particles are closest together

• Crest

• Compression

• Rarefaction

• Trough

Multiple Choice

The distance between one point on a compression and the corresponding point on the next compression in a sound wave

• Wavelength

• Compression

• Rarefaction

• Frenquency

Multiple Choice

True or false: as you move along the spectrum, radio to gamma waves, the wavelengths decrease in size (get smaller)

• true
• false

Multiple Choice

A wave with a large wavelength will have a ______ frequency and _____ energy

• high, low
• high, high
• low, high
• low, low

Multiple Choice

Select the correct order of waves on the EMS from the longest wavelength to the shortest wavelength

• Radio, Micro, Infra, Visible, Ultra, X-ray, Gamma
• Gamma, X-ray, Ultra, Vis, Infra, Micro, Radio
• Vis, Micro, Infra, Ultra, X-ray, Gamma, Radio
• Micro, Radio, Vis, Infra, Ultra, X-ray, Gamma

Multiple Choice

Which has the LONGEST wavelength and, therefore, the lowest frequency/energy

• Gamma Rays
• Radio Waves
• Visible Light
• Infrared rays

Multiple Choice

Which has the SHORTEST wavelength and, therefore, the highest frequency/most energy

• Radio waves
• Ultraviolet Rays
• Gamma Rays
• X-rays

Multiple Choice

Which section of the spectrum is the ONLY one we can see?

• X-rays
• Visible Light
• Gamma Rays
• Ultraviolet Rays

Multiple Choice

How are electromagnetic waves different from other waves? 

• They have very short wavelengths 
• They transmit energy instead of matter 
• They can travel through empty space
• They can change direction by reflection 

Multiple Choice

Which of the following electromagnetic waves has the lowest energy?

• gamma ray
• infrared wave
• visible light wave
• microwave

Multiple Choice

As the frequency of an electromagnetic wave increases, the amount of energy in that wave...

• increases.
• decreases.
• stays the same.

Multiple Choice

High frequency waves have _________ wavelengths.

• varying
• long
• the same
• short

Multiple Choice

The distance between two crests or two troughs of a wave is called:

• frequency
• amplitud
• wavelength
• hertz

Multiple Choice

How much of the electromagnetic spectrum is visible?

• All of it
• None of it
• Most of it
• Only a small part

Multiple Choice

The height of the wave from the rest position is known as the _____________.

• amplitude
• crest
• trough
• wavelength

Multiple Choice

What are electromagnetic waves?

• sound waves
• electric & magnetic fields (energy) that travel through empty space very quickly
• Someone's name
• things like longitudinal waves