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Free download in PDF Microwave Engineering Objective Type Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(21)
In microwave communication links, what causes intense fading in the 18GHz band ?
[A]
Rain
[B]
Fog
[C]
Dust
[D]
Snow
(22)
X-band frequencies are in which one of the following ranges?
[A]
8.0 to 12.0 GHz
[B]
12.4 to 16.4 GHz
[C]
3.5 to 5.5 GHz
[D]
5.5 to 8.0 GHz
(23)
Which of the following are microwave sources ?
[A]
Magnetron
[B]
TWTA
[C]
klystron
[D]
IMPATT
(24)
For a parabolic reflector of 5 meter diameter, the far field pattern measurement at 6 GHz should be carried out a distance of at least
[A]
2.0 km
[B]
1.5 km
[C]
1.0 km
[D]
o.5 km
(25)
Why is an attenuator used in a TWT ?
[A]
To prevent oscillations
[B]
To prevent saturation
[C]
To help bunching
[D]
To increase gain
Answer: To prevent oscillations
(26)
Which is the most common antenna to obtain a predetermined radiation pattern ?
[A]
Helical antenna
[B]
Corner reflector
[C]
Array antenna
[D]
Sectoral horn
(27)
In LOS-line of sight propagation systems, to take account of normal refraction, an effective earth radius factor k is used whose value is
[A]
½
[B]
4/3
[C]
4
[D]
None of these
(28)
The type of antenna to be used for producing circularly polarized beams is
[A]
helical antenna
[B]
paraboloid
[C]
pyramidal horn
[D]
log-periodic array
(29)
Which of the following can be used for amplification of microwave energy?
[A]
Travelling wave tube
[B]
Gunn diode
[C]
Magnetron
[D]
None of these
Answer: Travelling wave tube
(30)
The maximum theoretical output circuit efficiency of a double resonator klystron amplifier is
[A]
58%
[B]
85%
[C]
25%
[D]
None of these
31
The pulse frequency is equal to
[A]
Duty cycle/pulse width
[B]
Pulse width x peak power/average power
[C]
The reciprocal of the pulse repetition rate
[D]
All of these
Answer: Duty cycle/pulse width
32
The noise produced in a microwave tube due to random nature of emission and electron flow is called
[A]
Shot noise
[B]
Shannon noise
[C]
Johnson noise
[D]
Partition noise
33
If the peak power of pulsed microwave system is 104 W and the average power is 800 W, the the duty cycle will be
[A]
8%
[B]
0.08%
[C]
80%
[D]
0.8%
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