Georgia Science Grade 8

Chapter 18: Electromagnetic Waves

CRCT Practice

1
How are gamma rays produced?
A)by vibrating electric fields
B)by vibrating magnetic fields
C)by the absorption of infrared waves
D)by nuclear fission or fusion
2
How does the intensity of ultraviolet waves emitted by the Sun change as the wavelength of the ultraviolet waves decreases?

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A)The intensity increases.
B)The intensity decreases.
C)The intensity increases, then decreases.
D)The intensity doesn't change.
3
Which is NOT true about electromagnetic waves?
A)They can travel through matter.
B)They move by transferring matter.
C)They are produced by vibrating charges.
D)They can travel through empty space.
4
Which is represented by the circular lines around the current-carrying wire?

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A)direction of current
B)electric and magnetic field lines
C)magnetic field lines
D)electric field lines
5
Which type of electromagnetic waves has a frequency greater than visible light?
A)infrared waves
B)radio waves
C)magnetic field lines
D)microwaves
6
Which type of electromagnetic waves enables your body to produce vitamin D?
A)gamma rays
B)ultraviolet waves
C)visible light
D)infrared waves
7
Which property of a transverse wave is the distance from one crest to the next?
A)intensity
B)amplitude
C)frequency
D)wavelength
8
Earth's atmosphere is transparent to which type of electromagnetic waves?
A)gamma ray
B)ultraviolet waves
C)infrared waves
D)radio waves
9
The color that is seen when visible light waves enter the eye depends on which property of visible light waves?
A)wavelength
B)amplitude
C)direction
D)speed
10
Mars is 80,000,000 km from Earth. If a radio wave travels at a speed of 300,000 km/s, how long will it take the radio wave to travel from Earth to Mars?
A)0.004 s
B)0.04 s
C)267 s
D)26.7 s
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