MCAS Student Practice Questions
UNIT 6 – Electromagnetic Radiation Answers with Explanations
STANDARD 6.1
6.1. Recognize that electromagnetic waves are transverse waves and travel at the speed of light
through a vacuum.
BASIC CONCEPT: All Electromagnetic Waves travel at 3.0 x 10
8
m/s in a vacuum or air.
11-21 6.1
The table below lists the speed of light in four different
situations.
Situation
Speed of Light (m/s)
A
3.0 x 10
8
B
2.2 x 10
8
C
1.9 x 10
8
D
1.7 x 10
8
In which situation is light traveling through a vacuum?
A. Light travels at 3.0 x 10
8
in a vacuum.
8-9 6.1X-ray waves and infrared waves are both
electromagnetic waves. Which of the following
describes another property x-ray waves and infrared
waves share?
A.
Both waves are longitudinal.
B.
Both waves have the same frequency.
C.
Both waves have the same
wavelength.
D.
Both waves travel at the same speed
in a vacuum.
D. Light travels at 3.0 x 10
8
in a vacuum.
9-30 6.1 In an electromagnetic wave, an electric field
exists perpendicular to a magnetic field, and both fields are
perpendicular to the direction of travel of the wave. These
characteristics indicate that an electromagnetic wave is
which of the following wave types?
gravitational
longitudinal
mechanical
transverse
D. Perpendicular movement in a wave means it is a
transverse.
10-4 6.1
Which of the following properties is the same for all
electromagnetic waves in a vacuum?
amplitude
frequency
speed
wavelength
C. The speed is 3.0 x 10
8
for all EM waves.
7-38 6.1 Which of the following waves can travel
at a speed of 3 × 10
8
m/s?
A.
microwaves
B.
seismic waves
C.
ultrasonic waves
D.
water waves
The speed is 3.0 x 10
8
for all EM waves.
15-36 STD 6.1 Which of the following statements
describes electromagnetic waves?
A. They have mass. B. They are transverse waves.
C. They require a medium to propagate.
D. They travel at varying speeds through a vacuum.
15-28 STD 6.1 When astronauts landed on the Moon,
radio signals helped them communicate with people on
Earth. It took 1.3 s for a signal to travel from the Moon to
Earth. Which of the following is the best estimate of the
distance between Earth and the Moon?
A. 115,000,000 m B. 231,000,000 m C. 390,000,000 m
D. 780,000,000 m
D = R T, R = 3 x 10
8
m/s T = 1.3 s
D = 3 x 10
8
m/s x 1.3 s
Notice that 3 x 1.3 = 3.9, there is only one answer that has
39 in it. That is the answer.
STANDARD 6.2
6.2. Describe the electromagnetic spectrum in terms of frequency and wavelength and identify the location of
radio waves, microwaves, infrared radiation, visible light (red, orange, yellow, green, blue, indigo, and violet),
ultraviolet rays, x-rays, and gamma rays on the spectrum.
11-28 6.2 The figure below shows regions of the electromagnetic spectrum.
Which of the following devices is designed to produce electromagnetic radiation with the longest wavelength
in order to operate?
A. Light bulb B. microwave oven C. x-ray microscope D. FM radio transmitter.
Large wavelengths are at the Left end of the Spectrum.
10-13 6.2
Which of the following properties determines a color
in the visible light region of the electromagnetic
spectrum?
A.
acceleration
B.
amplitude
C.
frequency
D.
speed
8-1 6.2
Radio waves, visible light, and x-rays are examples of
electromagnetic waves that always differ from each
other in
A.
amplitude.
B.
intensity.
C.
temperature.
D.
wavelength.
9-6 6.2 Which of the following statements best
describes the visible spectrum of light as seen by the
human eye?
The lowest frequency appears red, and
the highest frequency appears violet.
The lowest frequency appears red, and the highest
frequency appears yellow.
The lowest frequency appears green, and the highest
frequency appears violet.
The lowest frequency appears green, and the highest
frequency appears yellow.
9-21 6.2
Which of the following statements best describes an
electromagnetic wave with a long wavelength?
It has a low frequency and can travel in
a vacuum.
It has a high frequency and can travel in a
vacuum.
It has a low frequency and can only travel in a
medium.
It has a high frequency and can only travel in a
medium.
EM waves differ in Wavelength and Frequency.
RED = Low Frequency (High Wavelength)
VIOLET = High Frequency (Low Wavelength)
All EM waves can travel in a vacuum. Long
Wavelength = Low Frequency
8-13 6.2
Suppose a scientist detects an electromagnetic wave
with a frequency higher than those of gamma rays.
The scientist labels this wave a Z-ray. Which of the
following would always be true of a Z-ray?
A.
A Z-ray would have a lesser
amplitude than gamma rays.
B.
A Z-ray would have a greater
amplitude than gamma rays.
C.
A Z-ray would have a shorter
wavelength than gamma rays.
D.
A Z-ray would have a longer
wavelength than gamma rays.
Higher Frequency means a shorter wavelength.
7-31 4.2
Which of the following waves travels fastest?
A.
water waves in oceans
B.
seismic waves in rocks
C.
sound waves from a violin string
D.
electromagnetic waves from the Sun
EM (including Light) are the fastest waves.
7-29 6.2 & 4.1 Which of the following graphs best represents the relationship of the frequency of an
electromagnetic wave to its wavelength?
D. As wavelength becomes longer the frequency becomes shorter.
7-35 4.2
Which of the following can carry light waves but
not sound waves?
air
steel
water
vacuum
Remember that space is a vacuum and light from the
sun makes it to Earth.
7-42 6.2
Ultraviolet light has a shorter wavelength than
visible light. Which of the following is another
way ultraviolet light can be compared to visible
light?
Ultraviolet light has a lower
frequency than visible light.
Ultraviolet light has a higher
frequency than visible light.
Ultraviolet light travels faster
than visible light.
Ultraviolet light travels slower
than visible light.
Wavelength and Frequency are inversely related.
When one is high the other is low.
8-13 6.2 Suppose a scientist detects an electromagnetic
wave with a frequency higher than those of gamma rays.
The scientist labels this wave a Z-ray. Which of the
following would always be true of a Z-ray?
A. A Z-ray would have a lesser amplitude than a gamma ray.
B. A Z-ray would have a greater amplitude than a gamma ray.
C. A Z-ray would have a shorter wavelength than gamma rays.
D. A Z-ray would have a longer wavelength than gamma rays.
7-31 4.2 Which of the following waves travels fastest?
A. water waves in oceans
B. seismic waves in rocks
C. sound waves from a violin string
D. electromagnetic waves from the Sun
The speed of light is the fastest speed that anything can go
OPEN RESPONSE
10-32
Standard: 6.2 - Describe the electromagnetic spectrum in terms of frequency and wavelength and identify the locations of
radio waves, microwaves, infrared radiation, visible light (red, orange, yellow, green, blue, indigo, and violet), ultraviolet
rays, x-rays, and gamma rays on the spectrum.
When some elements are put into a flame, they emit colored light. Yellow light is emitted from one element and violet light
is emitted from another element.
a.
Describe the differences between yellow light and violet light in terms of frequency and wavelength.
The diagram below represents violet light.
Remember the Order of the Spectrum : Starting with High Wavelength R O Y G B I V ending with
Short Wavelength. Use this information to answer the question:
Yellow light has a shorter wavelength than Violet light. Yellow light has a higher frequency than
violet light.
b.
Copy the diagram of violet light into your Student Answer Booklet. Below your diagram, draw and label a
representation of yellow light that illustrates how its frequency and wavelength are different from that of violet
light.
Yellow has longer wavelength and lower frequency
c.
Yellow light and violet light are both in the visible range of the electromagnetic spectrum. Identify two other
similarities between yellow light and violet light.
Yellow light and Violet light both travel at the speed of light, they also
travel through a vacuum.