Online Questions and Answers Topic Outline
- MCQs in Electromagnetic Radiation
- MCQs in Radio Spectrum
- MCQs in Wave Propagation
- MCQs in Radiation Patterns
- MCQs in Wavelength Calculations
- MCQs in Radiation Resistance
- MCQs in Diversity Systems
MCQs in Radiation and Wave Propagation Series
Following is the list of multiple choice questions in this brand new series:
Continue Practice Exam Test Questions Part II of the Series
51. Indicate which one of the following terms applies to troposcatter propagation
- a. SIDs
- b. fading
- c. atmospheric storms
- d. faraday rotation
52. VLF waves are used for some types of services because
- a. of the low power required
- b the transmitting antennas are of convenient size
- c. they are very reliable
- d. they penetrate the ionosphere easily
53. Indicate which of the following frequencies cannot be used for reliable beyond-the-horizon terrestrial communications without repeaters
- a. 20 KHz
- b. 15 MHz
- c. 900 MHz
- d. 12 GHz
54. High-frequency waves are
- a. absorbed by the F2 layer
- b. reflected by the D layer
- c. capable of use for long-distance communications on the moon
- d. affected by the solar cycle
55. Distances near the skip distance should be used for sky-wave propagation
- a. to avoid tilting
- b. to prevent sky-wave and upper ray interference
- c. to avoid the faraday effect
- d. so as not to exceed the critical frequency
56. A ship-to-ship communications system is plague by fading. The best solution seems to be the use of
- a. a more directional antenna
- b. a broadband antenna
- c. frequency diversity
- d. space diversity
57. A range of microwave frequencies more easily passed by the atmosphere than are the others is called a
- a. window
- b. critical frequency
- c. gyro frequency range
- d. resonance in the atmosphere
58. frequencies in the UHF range normally propagate by means of
- a. ground waves.
- b. sky waves
- c. surface waves
- d. space waves
59. Tropospheric scatter is used with frequencies in the following range
- a. HF
- b. VHF
- c. UHF
- d. VLF
60. The ground wave eventually disappears as one moves away from the transmitter because of
- a. interference from the sky wave
- b. loss of line – of – sight conditions
- c. maximum single-hop distance limitation
- d. tilting
61. in electromagnetic waves, polarization means
- a. the physical orientation of magnetic field in space
- b. the physical orientation of electric field in space
- c. ionization
- d. the presence of positive and negative ions
62. an electromagnetic waves travel in free space, only one of the following can happen to them.
- a. absorption
- b. attenuation
- c. refraction
- d. reflection
63. the absorption of a radio waves by the atmosphere depends on
- a. their frequency
- b. their distance from the transmitter
- c. the polarization of the waves
- d. the polarization of the atmosphere
64. diffraction of electromagnetic waves
- a. is caused by reflections from the ground
- b. arises only with spherical wavefronts
- c. will occur when the waves pass through a large slot
- d. may occur around the edge of a sharp object
65. In an electromagnetic wave the electric field is
- a. Parallel to both magnetic field and the wave direction
- b. Perpendicular to both the magnetic field and the wave direction
- c. Parallel to the magnetic field and perpendicular to the wave direction
- d. Perpendicular to the magnetic field and parallel to the wave direction
66. The highest frequencies are found in
- a. X-rays
- b. Radio waves
- c. Ultraviolet rays
- d. Radar waves
67. Electromagnetic waves transport
- a. Wavelength
- b. Charge
- c. Frequency
- d. Energy
68. The ionosphere is a region of ionized gas in the upper atmosphere. The ionosphere is responsible for
- a. The blue color of the sky
- b. Rainbows
- c. Long distance radio communication
- d. The ability of satellites to orbit the earth
69. Light of which the following colors has the shortest wavelength
- a. Red
- b. Yellow
- c. Blue
- d. Green
70. The quality in sound that corresponds to color in light is
- a. Amplitude
- b. Resonance
- c. Waveform
- d. Pitch
71. All real images
- a. Are erect
- b. Can appear on screen
- c. Are inverted
- d. Cannot appear on a screen
72. When a beam of light enters one medium from another, a quality that never changes is its
- a. Direction
- b. Frequency
- c. Speed
- d. Wavelength
73. Relative to the angle of incidence, the angle of refraction
- a. Is smaller
- b. Is larger
- c. Is the same
- d. Either A or B above
74. A light ray enters one medium from another along the normal. The angle of refraction is
- a. 0
- b. 90 degrees
- c. Equal to the critical angle
- d. Dependent on the indexes of refraction of the two media
75. What layer aids MF surface-wave propagation a little and reflects some HF waves in daytime?
- a. E layer
- b. D layer
- c. F1 layer
- d. F2 layer
76. Dispersion is the term used to describe
- a. The splitting of white light into its component colors in refraction
- b. The propagation of light in straight lines
- c. The bending of a beam of light when it goes from one medium to another
- d. The bending of a beam of light when it strikes a mirror
77. The depth of an objects submerged in a transparent liquid
- a. Always seems less than its actual depth
- b. Always seems more than its actual depth
- c. May seems more than its actual depth, depending on the index of refraction of the liquid
- d. May seem less or more than its actual depth depending on the angle of view
78. Total internal reflection can occur when light passes from one medium to another
- a. That has a lower index of refraction
- b. That has a larger index of refraction
- c. That has the same index of refraction
- d. At less than the critical angle
79. When the light ray approaches a glass-air interface from the glass side at the critical angle, the angle of refraction is
- a. 0
- b. 90 degrees
- c. 45 degrees
- d. Equal to the angle of incidence
80. The brightness of light source is called its luminous intensity , whose unit is
- a. Candela
- b. Lux
- c. Lumen
- d. Footcandle
81. Luminous efficiency is least for a
- a. Low-wattage light bulb
- b. Mercury vapor lamp
- c. High-wattage light bulb
- d. Fluorescent tube
82. The minimum illumination recommended for reading is
- a. 8000 cd
- b. 8000 lx
- c. 8000 lm
- d. 800 W
83. Light enters a glass plate whose index of refraction is 1.6 at an angle of incidence of 30 degrees . the angle of refraction is
- a. 18 degrees
- b. 48 degrees
- c. 19 degrees
- d. 53 degrees
84. Light leaves a slab of transparent material whose index of refraction is 2 at an angle of refraction of 0 degrees. The angle of incidence is
- a. 0 degrees
- b. 45 degrees
- c. 30 degrees
- d. 90 degrees
85. Light enters a glass plate at an angle of incidence of 40 degrees and is refracted at an angle refraction of 25 degrees. The index refraction of the glass is
- a. 0.625
- b. 1.52
- c. 0.66
- d. 1.6
86. An underwater swimmer shines a flash light beam upward at an angle of incidence of 40 degrees. The angle of refraction is 60 degrees. The index of refraction of water is
- a. 0.67
- b. 1.3
- c. 0.74
- d. 1.5
87. The critical angle of incidence for light going from crown glass (n=1.5) to ice (n=1.3) is
- a. 12 degrees
- b. 50 degrees
- c. 42 degrees
- d. 60 degrees
88. The solid angle subtended by a hemisphere about its center is
- a. π/2 sr
- b. 2 π sr
- c. π sr
- d. depends on the radius of the hemisphere
89. the luminous flux emitted by a 60-cd isotropic light source is concentrated on an area of 0.5m2. the illumination of the area is
- a. 9.6 lx
- b. 377 lx
- c. 120 lx
- d. 1508 lx
90. Microwave signals propagate by way of the
- a. Direct wave
- b. Sky wave
- c. Surface wave
- d. Standing wave
91. The ionosphere causes radio signals to be
- a. Diffused
- b. Absorbed
- c. Refracted
- d. Reflected
92. Ground wave communications is most effective in what frequency range?
- a. 300 KHz to 3 MHz
- b. 3 to 30 MHz
- c. 30 to 300 MHz
- d. Above 300 MHz
93. The ionosphere has its greatest effect on signals in what frequency range?
- a. 300 KHz to 3 MHz
- b. 3 to 30 MHz
- c. 30 to 300 MHz
- d. Above 300 MHz
94. The type of radio wave responsible for long distance communications by multiple skips is the
- a. Ground wave
- b. Direct wave
- c. Surface wave
- d. Sky wave
95. Line of sight communications is not a factor in which frequency range?
- a. VHF
- b. UHF
- c. HF
- d. Microwave
96. A microwave-transmitting antenna is 550ft high. The receiving antenna is 200ft high. The minimum transmission distance is
- a. 20 mi
- b. 33.2 mi
- c. 38.7 mi
- d. 53.2 mi
97. To increase the transmission distance of UHF signal, which of the following should be done?
- a. Increase antenna gain
- b. Increase antenna height
- c. Increase transmitter power
- d. Increase receiver sensitivity
98. States that power density is inversely proportional to the distance from its source.
- a. Principle of reciprocity
- b. Inverse square law
- c. Huygen’s Princple
- d. Faraday’s law
99. gets in contact with the ionosphere and reflected by it.
- a. Space wave
- b. Sky wave
- c. Surface wave
- d. Satellite wave
100. Highest layer in the ionosphere
- a. F1
- b. D
- c. F2
- d. E
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