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 III of the Series
101. Next lowest layer in the ionosphere.
- a. D
- b. E
- c. F1
- d. F2
102. What is the primary cause of ionization in the atmosphere?
- a. Sun spot
- b. Cosmic rays
- c. Galactic disturbance
- d. Ultraviolet radiation
103. Which layer does not disappear at night?
- a. D
- b. E
- c. F1
- d. F2
104. Which of the following uses surface wave propagation?
- a. ELF
- b. VLF
- c. MF
- d. All of these
105. The ability of the ionosphere to reflect a radio wave back to the earth is determined by
- a. Operating frequency
- b. Ion density
- c. Angle of incidence
- d. All of these
106. Highest frequency that can be used for sky wave propagation between two given points on earth.
- a. Critical frequency
- b. MUF
- c. Cut –off frequency
- d. UHF
107. The shortest distance measured along the earth’s surface that a sky wave is returned to earth.
- a. MUF
- b. Quarter-wavelength
- c. Skip distance
- d. Skip zone
108. Fluctuation in the signal strength at the receiver.
- a. Interference
- b. Fading
- c. Tracking
- d. Variable frequency
109. Two or more antennas are used separated by several wavelengths
- a. Space diversity
- b. Frequency diversity
- c. Hybrid diversity
- d. Polarization diversity
110. Two or more receivers are used using a single antenna.
- a. Space diversity
- b. Frequency diversity
- c. Hybrid diversity
- d. Polarization diversity
111. One of the following is not a cause of fading.
- a. Interference between upper and lower rays of a sky wave.
- b. Sky waves arriving at different number of hops
- c. Interference due to ground reflected wave and sky wave
- d. Diversity
112. What do you call the gigantic emissions of hydrogen from the sun?
- a. Solar flares
- b. SIDs
- c. Kennely-Heaviside
- d. Sun spots
113. Sudden ionospheric disturbance
- a. Solar flares
- b. SIDs
- c. Sun spots
- d. Intertropical convergence
114. A means beyond the line of sight propagation of UHF signals.
- a. Microwave propagation
- b. Space wave propagation
- c. Troposcatter propagation
- d. Surface wave propagation
115. Two directional antennas are pointed so that their beams intersect in the troposphere.
- a. Skywave
- b. Surface wave
- c. Microwave
- d. Troposcatter
116. Super refraction.
- a. Ducting
- b. Trposcatter
- c. Skywave
- d. Space wave
117. A layer of warm air trapped above cooler air
- a. Troposphere
- b. SID
- c. Duct
- d. Huygen’s principle
118. Corresponds to voltage
- a. Electric field
- b. Magnetic field
- c. Gyro
- d. Direction of propagation
119. Absence of reception
- a. Skip distance
- b. Maximum usable
- c. Shadow zone
- d. Twilight zone
120. Each point in a spherical waveform maybe a source of a secondary spherical wavefront.
- a. Senll’s law
- b. Huygen’s principle
- c. Rayleigh’s principle
- d. De Morgan’s theorem
121. Ducting occurs in which region of the atmosphere?
- a. Stratosphere
- b. Troposphere
- c. Ionosphere
- d. Ozone layer
122. When is the E region most ionized?
- a. At midday
- b. At midnight
- c. At duck
- d. At dawn
123. Transequatorial propagation is best during
- a. Night time
- b. Afternoon or early evening
- c. Noontime
- d. Morning
124. Which of the following is most affected by knife-edge refraction?
- a. Very high and ultra high frequencies
- b. High frequencies
- c. Medium frequency
- d. Low frequency
125. Which ionosphere layer has an average height of 225 km at night?
- a. D layer
- b. E layer
- c. F1 layer
- d. F2 layer
126. A range of frequency little attenuated by the atmosphere is called
- a. slide
- b. door
- c. window
- d. frame
127. It is defined as either of two acute angles formed by the intersection of the two portions of the tropospheric scatter beam tangent to the earth’s surface.
- a. critical angle
- b. scatter angle
- c. backscatter angle
- d. sidescatter angle
128. It is a device that permits two different transmitters to operate with a single antenna.
- a. duplexer
- b. diplexer
- c. isolator
- d. circulator
129. It is a gradual shift in polarization of the signal in the medium.
- a. fading
- b. faraday effect
- c. ghosting
- d. multipath fading
130. A diversity scheme wherein the receiver receives two fading signals from two different directions.
- a. frequency diversity
- b. time diversity
- c. angle diversity
- d. space diversity
131. The radio wavelength known as _________ falls within the medium frequency range.
- a. centimetric wave
- b. decametric wave
- c. hectometric wave
- d. myriametric wave
132. The most dense of all ionized layer of the ionosphere
- a. E
- b. F1
- c. F2
- d. D
133. The frequency band used as sub-carriers, or signals which carry the baseband modulating information but in turn modulate another higher-frequency carrier is _________.
- a. LF
- b. MF
- c. VLF
- d. VH
134. The range of frequency band termed as super high frequency (SHF) is within _________.
- a. 30 – 300 GHz
- b. 30 – 300 MHz
- c. 3 – 30 GHz
- d. 300 – 3000 MHz
135. Electric field that lies in a plane perpendicular to the earth’s surface.
- a. circular polarization
- b. vertical polarization
- c. horizontal polarization
- d. elliptical polarization
136. The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization
- a. is vertical
- b. is horizontal
- c. is circular
- d. cannot be determined from the information given
137. The surface wave is effective only at frequencies below about _________ MHz.
- a. 30
- b. 3
- c. 300
- d. 0.3
138. What wave propagation are attenuated within a few miles?
- a. space
- b. sky
- c. ground
- d. direct
139. What happens to wave velocity as it passes from air to ionosphere?
- a. increases
- b. decreases
- c. remain the same
- d. not a factor
140. What wavelength radiations tend to be transmitted entirely between ionosphere and earth?
- a. long
- b. short
- c. medium
- d. millimeter
141. What effect do sunspots have on the ionosphere?
- a. makes more rare and regular
- b. makes more dense and irregular
- c. makes less dense and regular
- d. makes less dense and irregular
142. What is a double-hop signal?
- a. ground, ionosphere, ground and back to ionosphere
- b. ground, ground, ionosphere, and ionosphere
- c. ionosphere, ionosphere, ground and ground
- d. ionosphere, ground, ionosphere and back to ground
143. What is the major cause of fading?
- a. phase difference
- b. topographic variation
- c. climate
- d. ionosphere variation
144. Where is the skip zone?
- a. between the sky and the first reflected wave
- b. between end of ground and first reflected wave
- c. between end of ground and farthest reflected wave
- d. between the end of sky to the farthest reflected wave
145. What wave is the same day or night?
- a. sky
- b. space
- c. direct
- d. ground
146. Why do HF communications system shift frequencies at different times of day?
- a. to take advantage of best reflected signals
- b. to conserve the energy used
- c. to create diversity
- d. to improve noise performance
147. Scatter transmission is used at what frequencies?
- a. EHF and VLF
- b. HF and VHF
- c. VHF and UHF
- d. ELF and VLF
148. Over what areas ducts often form?
- a. desert
- b. water
- c. forest
- d. mountain
149. Polarization named for _________ component of the wave?
- a. static
- b. magnetic
- c. direction
- d. propagation
150. What polarization is employed in an AM broadcasting?
- a. horizontal
- b. parallel
- c. transverse
- d. vertical
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