MCQ in Radiation and Wave Propagation Part 2 | ECE Board Exam

This is the Multiples Choice Questions Part 2 of the Series in Radiation and Wave Propagation as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

MCQ Topic Outline included in ECE Board Exam Syllabi

• MCQ in Electromagnetic Radiation
• MCQ in Radio Spectrum
• MCQ in Wave Propagation
• MCQ in Radiation Patterns
• MCQ in Wavelength Calculations
• MCQ in Radiation Resistance
• MCQ in Diversity Systems

Continue Practice Exam Test Questions Part 2 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 wave fronts

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 flashlight 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. 2π 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 0.5 m². 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

Questions and Answers in Radiation and Wave Propagation Series

Following is the list of multiple choice questions in this brand new series:

Complete List of MCQ in Communications Engineering per topic