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question_answer1)
Virtual height of an ionosphere layer is........... the beat height
A)
less than done
clear
B)
equal to done
clear
C)
more than done
clear
D)
none of these done
clear
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question_answer2)
In ground wave propagation the absorption of waves
A)
decreases with frequency done
clear
B)
increases with frequency done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer3)
The ionosphere consists of
A)
positively charged layer done
clear
B)
negatively charged layer done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer4)
In radio receiver's tube EM84 is used as
A)
audio amplifier done
clear
B)
magic eye done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer5)
In a radio receiver the noise is generally increased by
A)
power supply done
clear
B)
mixer done
clear
C)
local oscillator done
clear
D)
none of these done
clear
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question_answer6)
The value of a resistor creating thermal noise is doubled. The noise power generated will be
A)
halved done
clear
B)
doubled done
clear
C)
unchanged done
clear
D)
none of these done
clear
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question_answer7)
Which of the following noise is of great importance at high frequencies?
A)
Flicker noise done
clear
B)
Transit-time noise done
clear
C)
Short noise done
clear
D)
None of these done
clear
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question_answer8)
Neper is
A)
equal to decibel done
clear
B)
smaller than decibel done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer9)
Which of the following crystal filter is used only at the higher frequencies?
A)
Half lattice done
clear
B)
Ladder done
clear
C)
Crystal gale done
clear
D)
None of these done
clear
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question_answer10)
The frequency at which the reactance of the two arms in a crystal gate are equal is
A)
zero done
clear
B)
maximum attenuation frequency done
clear
C)
both [a] and [b] done
clear
D)
none of the above done
clear
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question_answer11)
The effect of transit-time noise is significant in
A)
HP done
clear
B)
LF done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer12)
A beat frequency between 1500 kHz and 1955 kHz is
A)
455 kHz done
clear
B)
350 kHz done
clear
C)
665 kHz done
clear
D)
750 kHz done
clear
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question_answer13)
In troposcatter which of the following antenna is preferred?
A)
Parabolic antenna done
clear
B)
Lens antenna done
clear
C)
Both [a] and [b] done
clear
D)
None of these done
clear
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question_answer14)
In a radio receiver padders are provided
A)
to improve tracking done
clear
B)
to improve sensibility done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer15)
Diversity reception system is used to minimize the troubles due to
A)
synchronous fading done
clear
B)
general fading only done
clear
C)
both [a] and [b] done
clear
D)
none of the above done
clear
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question_answer16)
The output of a diode detector does not contain
A)
output signal done
clear
B)
modulating signal done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer17)
When power ratios are expressed in dB m, the reference power is
A)
1 mW done
clear
B)
3 mW done
clear
C)
2 mW done
clear
D)
5 mW done
clear
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question_answer18)
Which stage contains the primary of the first IF transformer
A)
Oscillator done
clear
B)
Detector done
clear
C)
Both [a] and [b] done
clear
D)
None of these done
clear
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question_answer19)
During heterodyne process in a receiver the modulation of the signal the signal
A)
increases done
clear
B)
decreases done
clear
C)
remains constant done
clear
D)
both [a] and [b] done
clear
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question_answer20)
Channel capacity is equal to
A)
parabolic antenna done
clear
B)
lens antenna done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer21)
If the image frequency is 2010 kHz, the frequency must be
A)
1350 kHz done
clear
B)
1500 kHz done
clear
C)
1700 kHz done
clear
D)
none of these done
clear
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question_answer22)
Three-point tracking is achieved by
A)
the padder capacitor done
clear
B)
variable selectivity done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer23)
The input of the mixer stage is
A)
RF signals only done
clear
B)
local oscillator signals only done
clear
C)
signals only done
clear
D)
both [a] and [b] done
clear
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question_answer24)
The disadvantage of tuned radio frequency receiver is
A)
band width variation done
clear
B)
in stability done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer25)
Radar is
A)
a mechanical device done
clear
B)
an electrical device done
clear
C)
a pneumatic device done
clear
D)
an electromagnetic device done
clear
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question_answer26)
The Chain Home Low System is effective within the rana of....... from the target,
A)
5 km done
clear
B)
7 km done
clear
C)
10 km done
clear
D)
15 km done
clear
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question_answer27)
Radars can be used under
A)
bad weather conditions done
clear
B)
good weather conditions done
clear
C)
all weather conditions done
clear
D)
none of these done
clear
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question_answer28)
Chain Home System was designed for the location and detection of
A)
enemy done
clear
B)
approaching aircraft bombers done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer29)
Air-traffic control radar monitors are installed
A)
in vicinity of airports done
clear
B)
enrooted between air terminals done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer30)
In communication receivers the fidelity is provided by
A)
audio stage done
clear
B)
mixer stage done
clear
C)
both [a] and [b] done
clear
D)
None of these done
clear
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question_answer31)
Surveillance raders detect and locate hostile targets for the purpose of
A)
military action done
clear
B)
proper military action done
clear
C)
war done
clear
D)
none of these done
clear
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question_answer32)
Radars are used in
A)
detection done
clear
B)
tracking of weather done
clear
C)
both [a] and [c] done
clear
D)
none of these done
clear
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question_answer33)
Radar can be used to guide
A)
vehicles done
clear
B)
space vehicles done
clear
C)
the science done
clear
D)
none of these done
clear
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question_answer34)
In Chain Home Low System, same aexial was used for
A)
transmission and modulation done
clear
B)
reception and modulation done
clear
C)
transmission and reception done
clear
D)
none of these done
clear
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question_answer35)
The performance of radar is unaffected by
A)
darkness done
clear
B)
fog done
clear
C)
rain done
clear
D)
[a], [b] and [c] done
clear
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question_answer36)
Chain Home Low System was first introduced in
A)
1952 done
clear
B)
1959 done
clear
C)
1964 done
clear
D)
1972 done
clear
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question_answer37)
In foul weather, radar is used with Ground Controlled Approach (GCA) System to guide aircrafts
A)
to a safe landing done
clear
B)
in any direction done
clear
C)
to fly in the sky done
clear
D)
none of the above done
clear
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question_answer38)
Distance Early Warning (DEW) radar/radars is/are used to detect the
A)
aircrafts done
clear
B)
enemies done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer39)
The techniques developed for radar have paved the way of more advanced research in
A)
solar system done
clear
B)
microwave done
clear
C)
spectroscopy done
clear
D)
none of these done
clear
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question_answer40)
Radar has vastly increased out knowledge of meteorology, aurora, meteors, and other objects of the
A)
sciences done
clear
B)
world done
clear
C)
solar system done
clear
D)
none of these done
clear
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question_answer41)
In Chain Home Low System, the target ranges were more than
A)
100 km done
clear
B)
85 km done
clear
C)
65 km done
clear
D)
75 km done
clear
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question_answer42)
When installed in ships or high flying aero planes, radars can be used under all weather conditions to find the positions of mountains and
A)
icebergs in the sea done
clear
B)
shore lines done
clear
C)
lakes etc. done
clear
D)
[a], [b] and [c] done
clear
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question_answer43)
Hartley law states that
A)
the maximum rate of information transmission depends on the depth of modulation done
clear
B)
me maximum rate of information transmission depends on the channel bandwidth. done
clear
C)
redundancy is essential done
clear
D)
only binary codes may be used. done
clear
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question_answer44)
The Ballistic Missile Early Warning Systems radar is used to detect the track of
A)
missiles done
clear
B)
ballistic missiles done
clear
C)
intercontinental ballistic missiles done
clear
D)
both [a] and [b] done
clear
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question_answer45)
Radar is used by military for
A)
surveillance done
clear
B)
safety done
clear
C)
weapons done
clear
D)
none of these done
clear
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question_answer46)
Radar can be used for the exploration of
A)
solar system done
clear
B)
interplanetary space done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer47)
Radar is used by ships, large and small, for navigation especially in
A)
bad weather done
clear
B)
with poor visibility done
clear
C)
[a] and [b] done
clear
D)
none of these done
clear
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question_answer48)
Chief civilian application of radar has been for....... navigation.
A)
marine done
clear
B)
air done
clear
C)
both [a] and [b] done
clear
D)
none of these done
clear
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question_answer49)
Radar can be used in
A)
satellites done
clear
B)
space research done
clear
C)
solar system done
clear
D)
none of these done
clear
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question_answer50)
Radar gives target's:
A)
Range done
clear
B)
Size done
clear
C)
Velocity and range done
clear
D)
Color done
clear
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