Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which one of the following is not an electromagnetic wave? 1)
A) infrared
B) radio waves
C) sound waves
D) gamma rays
E) ultraviolet
Answer: C
2) Which one of the following lists gives the correct order of the electromagnetic spectrum from low to 2)
high frequencies?
A) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays
B) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays
C) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
D) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays
E) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays
Answer: D
3) Which one of the following lists gives the correct order of the electromagnetic waves from longer 3)
wavelength to shorter wavelength?
A) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays
B) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays
C) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays
D) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays
E) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
Answer: A
4) In an electromagnetic wave in free space, the electric and magnetic fields are 4)
A) perpendicular to one another and parallel to the direction of wave propagation.
B) perpendicular to one another and perpendicular to the direction of wave propagation.
C) parallel to one another and perpendicular to the direction of wave propagation.
D) parallel to one another and parallel to the direction of wave propagation.
Answer: B
5) Which of the following statements about electromagnetic waves in free space are true? (There 5)
could be more than one correct choice.)
A) The higher-frequency travel faster than the lower-frequency waves.
B) The higher-frequency waves have shorter wavelengths than the lower-frequency waves.
C) The wavelengths of the visible waves are some of the shortest electromagnetic waves.
D) The electric field vector is always at right angles to the magnetic field vector.
E) The wavelengths of the visible waves are some of the longest electromagnetic waves.
Answer: B, D
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, 6) Which one of the following types of electromagnetic wave travels through space the fastest? 6)
A) infrared
B) radio waves
C) ultraviolet
D) microwaves
E) They all travel through space at the same speed.
Answer: E
7) The energy density of an electromagnetic wave in free space is 7)
A) 1/4 in the electric field and 3/4 in the magnetic field.
B) equally divided between the magnetic and the electric fields.
C) entirely in the magnetic field.
D) entirely in the electric field.
E) 1/4 in the magnetic field and 3/4 in the electric field.
Answer: B
8) For an electromagnetic wave in free space having an electric field of amplitude E and a magnetic 8)
field of amplitude B, the ratio of B/E is equal to
A) 1/c B) c C) 1/c2 D) c2 E) c
Answer: A
9) Which one of the following expressions is the correct representation for the speed of light in 9)
vacuum?
A) 1 / 0 µ0 B) µ0 C) 0 µ0 D) 0 / µ0 E) µ
Answer: A
10) Which of the following statements about electromagnetic waves in free space are true? (There 10)
could be more than one correct choice.)
A) The frequency of the electric field is higher than the frequency of the magnetic field.
B) The electric field carries more energy than the magnetic field.
C) The electric field carries the same mount of energy as the magnetic field.
D) The frequency of the magnetic field is the same as the frequency of the electric field.
E) The electric and magnetic fields have equal amplitudes.
Answer: C, D
11) Except for their color, a perfectly black (absorbing) object is identical to a perfectly white 11)
(reflecting) object. If identical light falls on both of these objects, what is true about the momentum
they will receive from this light?
A) The white object will receive twice as much as the black object.
B) The black object will receive four times as much as the white object.
C) They will both receive the same amount.
D) The black object will receive twice as much as the white object.
E) The white object will receive four times as much as the black object.
Answer: A
2
, 12) Two light beams of different frequency but the same intensity fall on a black (totally absorbing) 12)
surface, striking perpendicular to the surface. Which of the following statements are true? (There
could be more than one correct choice.)
A) Painting the surface white would not affect the pressure on it due to these beams.
B) The high-frequency beam exerts more pressure on the surface.
C) Both beams exert the same pressure on the surface.
D) The light beams exert no pressure on the surface because light is just energy.
E) If the surface were painted white (totally reflecting), the pressure on it would be less than
when it was black.
Answer: C
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
13) A cordless phone operates at 900 MHz. What is the wavelength of the electromagnetic 13)
wave used by this phone? (c = 3.0 × 108 m/s)
Answer: 0.33 m
14) An FM radio station broadcasts at 96.7 MHz. What is the wavelength of the radio wave 14)
used for this broadcast? (c = 3.0 × 108 m/s)
Answer: 3.1 m
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
15) What is the wavelength used by a radio station that broadcasts at a frequency of 920 kHz? (c = 3.00 15)
× 108 m/s)
A) 175 m B) 22.6 m C) 226 m D) 326 m E) 276 m
Answer: D
16) The frequency of a microwave signal is 9.76 GHz. What is its wavelength? (c = 3.00 × 10 8 m/s) 16)
A) 5.07 cm B) 3.07 cm C) 4.07 cm D) 2.07 cm E) 1.07 cm
Answer: B
17) What is the frequency of 20-mm microwaves? (c = 3.0 × 108 m/s) 17)
A) 15 GHz B) 100 MHz C) 400 MHz D) 73 GHz
Answer: A
18) The wavelength of an electromagnetic wave is 600 nm. What is its frequency? (c = 3.0 × 108 m/s) 18)
A) 300 × 1012 Hz
B) 600 × 1012 Hz
C) 500 × 1012 Hz
D) 200 × 1012 Hz
E) 400 × 1012 Hz
Answer: C
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, 19) A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the highest 19)
frequency associated with this portion of the spectrum? (c = 3.00 × 108 m/s)
A) 1.50 × 1015 Hz
B) 7.50 × 1013 Hz
C) 1.50 × 1014 Hz
D) 7.50 × 1014 Hz
E) 7.50 × 1015 Hz
Answer: A
20) A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the lowest 20)
frequency associated with this portion of the spectrum? (c = 3.00 × 108 m/s)
A) 7.50 × 1013 Hz
B) 7.50 × 1015 Hz
C) 1.50 × 1015 Hz
D) 1.50 × 1014 Hz
E) 7.50 × 1014 Hz
Answer: E
21) A 7.55 × 1014 Hz electromagnetic wave travels in carbon tetrachloride with a speed of 2.05 ×108 21)
m/s. What is the wavelength of the wave in this material?
A) 397 nm B) 272 nm C) 301 nm D) 338 nm E) 361 nm
Answer: B
22) The distance between two asteroids is 1600 km. How much time does it take for a light signal to go 22)
from one asteroid to the other? (c = 3.0 × 108 m/s)
A) 5.3 ms B) 19 ms C) 4.5 ms D) 19 µs E) 13 ms
Answer: A
23) How far does a beam of light travel in 2.0 ms? (c = 3.0 × 108 m/s) 23)
A) 0.66 × 105 m
B) 6.0 × 105 m
C) 60 m
D) 90 m
E) 70 m
Answer: B
24) How far does light travel in 1.0 µs? (c = 3.0 × 108 m/s) 24)
A) 0.30 km B) 3.0 × 1014 m C) 3.0 m D) 30 cm
Answer: A
25) How long does it take light to travel 1.0 m? (c = 3.0 × 108 m/s) 25)
A) 3.3 ns B) 3.3 s C) 3.3 ms D) 3.3 µs
Answer: A
26) How much time does it take a beam of light to travel 2.9 km through space. (c = 3.0 × 108 m/s) 26)
A) 9.7 ns B) 9.7 ps C) 9.7 µs D) 9.7 ms E) 9.7 s
Answer: C
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Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which one of the following is not an electromagnetic wave? 1)
A) infrared
B) radio waves
C) sound waves
D) gamma rays
E) ultraviolet
Answer: C
2) Which one of the following lists gives the correct order of the electromagnetic spectrum from low to 2)
high frequencies?
A) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays
B) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays
C) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
D) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays
E) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays
Answer: D
3) Which one of the following lists gives the correct order of the electromagnetic waves from longer 3)
wavelength to shorter wavelength?
A) radio waves, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays
B) radio waves, ultraviolet, x-rays, microwaves, infrared, visible, gamma rays
C) radio waves, microwaves, visible, x-rays, infrared, ultraviolet, gamma rays
D) radio waves, infrared, microwaves, ultraviolet, visible, x-rays, gamma rays
E) radio waves, infrared, x-rays, microwaves, ultraviolet, visible, gamma rays
Answer: A
4) In an electromagnetic wave in free space, the electric and magnetic fields are 4)
A) perpendicular to one another and parallel to the direction of wave propagation.
B) perpendicular to one another and perpendicular to the direction of wave propagation.
C) parallel to one another and perpendicular to the direction of wave propagation.
D) parallel to one another and parallel to the direction of wave propagation.
Answer: B
5) Which of the following statements about electromagnetic waves in free space are true? (There 5)
could be more than one correct choice.)
A) The higher-frequency travel faster than the lower-frequency waves.
B) The higher-frequency waves have shorter wavelengths than the lower-frequency waves.
C) The wavelengths of the visible waves are some of the shortest electromagnetic waves.
D) The electric field vector is always at right angles to the magnetic field vector.
E) The wavelengths of the visible waves are some of the longest electromagnetic waves.
Answer: B, D
1
, 6) Which one of the following types of electromagnetic wave travels through space the fastest? 6)
A) infrared
B) radio waves
C) ultraviolet
D) microwaves
E) They all travel through space at the same speed.
Answer: E
7) The energy density of an electromagnetic wave in free space is 7)
A) 1/4 in the electric field and 3/4 in the magnetic field.
B) equally divided between the magnetic and the electric fields.
C) entirely in the magnetic field.
D) entirely in the electric field.
E) 1/4 in the magnetic field and 3/4 in the electric field.
Answer: B
8) For an electromagnetic wave in free space having an electric field of amplitude E and a magnetic 8)
field of amplitude B, the ratio of B/E is equal to
A) 1/c B) c C) 1/c2 D) c2 E) c
Answer: A
9) Which one of the following expressions is the correct representation for the speed of light in 9)
vacuum?
A) 1 / 0 µ0 B) µ0 C) 0 µ0 D) 0 / µ0 E) µ
Answer: A
10) Which of the following statements about electromagnetic waves in free space are true? (There 10)
could be more than one correct choice.)
A) The frequency of the electric field is higher than the frequency of the magnetic field.
B) The electric field carries more energy than the magnetic field.
C) The electric field carries the same mount of energy as the magnetic field.
D) The frequency of the magnetic field is the same as the frequency of the electric field.
E) The electric and magnetic fields have equal amplitudes.
Answer: C, D
11) Except for their color, a perfectly black (absorbing) object is identical to a perfectly white 11)
(reflecting) object. If identical light falls on both of these objects, what is true about the momentum
they will receive from this light?
A) The white object will receive twice as much as the black object.
B) The black object will receive four times as much as the white object.
C) They will both receive the same amount.
D) The black object will receive twice as much as the white object.
E) The white object will receive four times as much as the black object.
Answer: A
2
, 12) Two light beams of different frequency but the same intensity fall on a black (totally absorbing) 12)
surface, striking perpendicular to the surface. Which of the following statements are true? (There
could be more than one correct choice.)
A) Painting the surface white would not affect the pressure on it due to these beams.
B) The high-frequency beam exerts more pressure on the surface.
C) Both beams exert the same pressure on the surface.
D) The light beams exert no pressure on the surface because light is just energy.
E) If the surface were painted white (totally reflecting), the pressure on it would be less than
when it was black.
Answer: C
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
13) A cordless phone operates at 900 MHz. What is the wavelength of the electromagnetic 13)
wave used by this phone? (c = 3.0 × 108 m/s)
Answer: 0.33 m
14) An FM radio station broadcasts at 96.7 MHz. What is the wavelength of the radio wave 14)
used for this broadcast? (c = 3.0 × 108 m/s)
Answer: 3.1 m
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
15) What is the wavelength used by a radio station that broadcasts at a frequency of 920 kHz? (c = 3.00 15)
× 108 m/s)
A) 175 m B) 22.6 m C) 226 m D) 326 m E) 276 m
Answer: D
16) The frequency of a microwave signal is 9.76 GHz. What is its wavelength? (c = 3.00 × 10 8 m/s) 16)
A) 5.07 cm B) 3.07 cm C) 4.07 cm D) 2.07 cm E) 1.07 cm
Answer: B
17) What is the frequency of 20-mm microwaves? (c = 3.0 × 108 m/s) 17)
A) 15 GHz B) 100 MHz C) 400 MHz D) 73 GHz
Answer: A
18) The wavelength of an electromagnetic wave is 600 nm. What is its frequency? (c = 3.0 × 108 m/s) 18)
A) 300 × 1012 Hz
B) 600 × 1012 Hz
C) 500 × 1012 Hz
D) 200 × 1012 Hz
E) 400 × 1012 Hz
Answer: C
3
, 19) A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the highest 19)
frequency associated with this portion of the spectrum? (c = 3.00 × 108 m/s)
A) 1.50 × 1015 Hz
B) 7.50 × 1013 Hz
C) 1.50 × 1014 Hz
D) 7.50 × 1014 Hz
E) 7.50 × 1015 Hz
Answer: A
20) A certain part of the electromagnetic spectrum ranges from 200 nm to 400 nm. What is the lowest 20)
frequency associated with this portion of the spectrum? (c = 3.00 × 108 m/s)
A) 7.50 × 1013 Hz
B) 7.50 × 1015 Hz
C) 1.50 × 1015 Hz
D) 1.50 × 1014 Hz
E) 7.50 × 1014 Hz
Answer: E
21) A 7.55 × 1014 Hz electromagnetic wave travels in carbon tetrachloride with a speed of 2.05 ×108 21)
m/s. What is the wavelength of the wave in this material?
A) 397 nm B) 272 nm C) 301 nm D) 338 nm E) 361 nm
Answer: B
22) The distance between two asteroids is 1600 km. How much time does it take for a light signal to go 22)
from one asteroid to the other? (c = 3.0 × 108 m/s)
A) 5.3 ms B) 19 ms C) 4.5 ms D) 19 µs E) 13 ms
Answer: A
23) How far does a beam of light travel in 2.0 ms? (c = 3.0 × 108 m/s) 23)
A) 0.66 × 105 m
B) 6.0 × 105 m
C) 60 m
D) 90 m
E) 70 m
Answer: B
24) How far does light travel in 1.0 µs? (c = 3.0 × 108 m/s) 24)
A) 0.30 km B) 3.0 × 1014 m C) 3.0 m D) 30 cm
Answer: A
25) How long does it take light to travel 1.0 m? (c = 3.0 × 108 m/s) 25)
A) 3.3 ns B) 3.3 s C) 3.3 ms D) 3.3 µs
Answer: A
26) How much time does it take a beam of light to travel 2.9 km through space. (c = 3.0 × 108 m/s) 26)
A) 9.7 ns B) 9.7 ps C) 9.7 µs D) 9.7 ms E) 9.7 s
Answer: C
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