Que. 1 Tropospheric scatter is used with freq. in
A HF
B VHF
C UHF
D VLF
Que. 2 Higher value of SWR signifies
A higher ohmic lossless
B higher ohmic lossless and possibility of insulation breakdown
C higher radiation resistance
D none of these
Que. 3 A transmission line quarter wave section is used to reject an interfering
freq. of 100mhz its approximate length is
A 3m
B 1.5m
C 75cm
D none of these
Que. 4 The quarter wave monopole at a freq. of 1mhz has a length of
A 1m
B 75m
C 150m
D 225m
Que. 5 medium wave radio signal may be received at for off distance at night
because
A radio wave travels faster at night
B ground wave attenuation is low at night
C the sky wave is stronger at night
D there is no fading at night
Que. 6 For a dipole antenna
A The radition intensity is maximum along the normal to the dipole axis
B The current distribution along its length is uniform ieeespective
of the length
C The effective length equals its physical length
D The input impedance is independent of the location of the feed point
Que. 7 The polarization of electromagnetic wave is
A the direction of electric and magnetic field
B the direction of electric field
C the direction of magnetic field
D none of above
Que. 8 Telex is a
A Telephone services between various subscriber
B Teleprinter services between various subscriber
C Television services between various subscriber
D Telegraph services between various subscriber
Que. 9 The purpose of peak clipper ckt in radio transmitter is to
A reduce bandwidth
B increase bandwidth
C prevent over modulation
D regulate oscillator input voltage
Que. 10 The current distribution of a half wave dipole is
A uniform
B sinusoidal
C triangular
D complex
Que. 11 distance near the skip distance should be used for sky-wave propogation
A to avoide the faraday effect
B to avoide tilting
C To prevent sky-wave and upper ray interface
D so as to exceed the critical freq.
Que. 12 in air a lossless transmission line of length 50cm with L=10micro H/m,C=40pF/m
is operated at 25Mhz its electrical path length is
A 0.5meter
B lemda meters
C (pi)/2 radians
D 180 degree
Que. 13 A coil has an inductance of 1H. If a current changing @ 1A/secs
A induces 1v in another coil
B causes a back emf of1v
C causes a aiding emf of1v
D causes transformer action
Que. 14 A parabolic dish antenna with a effenciency of 55% and an operating freq.
of 10Ghz has a gain of 43.82dB.Its diameter is
A 1m
B 2m
C 4m
D 8m
Que. 15 Which of the following represents 'E3(16) '?
A (1 CE) + (A2)
16 16
B (1 BC) + (DE)
16 16
C (2 BC) - (1 DE)
16 16
D (200) - (11 D)
16 16
Que. 16 The charecteristic impedance of a transmission line with inductance 0.294
micro H/m.and capacitance 60 pF/m is
A 49 W
B 60 W
C 70 W
D 140 W
Que. 17 The circles on the Smith chart
A represents normalised constant resistance or conductance
B represents normalised constant reactance or susceptance
C are constant SWR circles
D are connected 'p'circles
Que. 18 In a parasitic array,
A Only one of the element is driven, the others get excitation
from the field produced
B all the elements of the array are the driven elements
C there are more than one directors
D there is one driven elemnts one director and one reflector
Que. 19 In H-plane metal plate lens antenna travelling wave fronts
A totally retarded
B retarded
C accelerated
D neither accelerated nor retarted
Que. 20 The type of antenna to be used for produceing circulary polarised beams
is
A pyramidal horn
B log-perodic array
C paraboloid
D helical antenna
Que. 21 In telephones,the dial tone has a freq. of
A 1hz
B 13 hz
C 33 hz
D 133 hz
Que. 22 the transmitting antenna to be used for telivision broadcast is necessarily
A a parabolic reflector
B a high directive antenna
C an omnidirectional antenna
D none of these
Que. 23 A standard refrences antenna for directivity is
A element doublet
B half wave dipole
C isotropic antenna
D Rhombic antenna
Que. 24 maximum voltage is induced in a loop antenna if it is placed
A parallel to the incoming wave
B all right angles to the incoming wave
C at 45degree to the incoming wave
D none of the above
Que. 25 the advantage of marconi antenna over the ungrounded antenna is that
A only one fourth of the height is required as compared ungrounded
antenna
B one half of the height is required as compared ungrounded antenna
C no capacitance is required
D none of the above
Que. 26 The antenna best guided by a wave guide
A biconical
B horn
C helical
D discone
Que. 27 Night effect is most prominent in
A Adcock antenna
B vertical antenna
C loop antenna
D all of these
Que. 28 UHF and microwaves in the freq. range 300mHz to 30 Ghz can be best transmitted
using
A sky wave propagation
B ground wave propagation
C duct propagation
D none of these propagation
Que. 29 In a medium if e.u and 0- are constant through out the medium then it
is known as
A perfect medium
B distributed medium
C homogeneous medium
D dielectric medium
Que. 30 When an electromagnetic wave travelling in one medium strikes upon a secound
medium the wave will be
A totally transmitted
B totally reflected
C neither transmitted nor reflected
D partially transmitted and partially reflected
Que. 31 the shortest stub length in (lemda) required to produce a reactance =
Z(0) is
A (lemda)
B (lemda)/8
C (lemda)/4
D 2*(lemda)
Que. 32 The signals contaminated with large noise are demodulated by
A envelope dector
B synchronous dector
C envelope dector followed by low pass filter
D envelope dector followed by high pass filter
Que. 33 The effect of ground on radiation pattern is
A to increas its wavelength
B to produce more number of nulls
C to cause cancellation of radiation alone the around
D both b and c above
Que. 34 the ground wave coverage of the medium wave transmitter is 100 km and
in the night the first reflected ray is at 800km the skip distance
is
A 900km
B 700km
C 100km
D 800km
Que. 35 Which of the following has the least wavelength
A X-Rays
B Ultra-violet
C infra-red
D UHF
Que. 36 The charecteristic impedance of a transmission line is
A directly proportional to it's length
B inversly proportional to it's length
C independent of its length
D non of these
Que. 37 Zoning is used with a dielectric anteena in order to
A permit pin point focusing
B reduce the bulk of the lens
C increase the band width of the lens
D correct the curvature of the wave front from the horn that is
too short
Que. 38 Cassegrain feed is used with a parabolic reflector to
A reduce the size of the main reflector
B increase the gain of the system
C increase the beam width of the system
D allow the feed to be placed at a convenient point
Que. 39 A prominent wave should have
A no phase shift
B no attenuation
C highest cutoff freq.
D lowest cutoff feq.
Que. 40 Circular polarization is said to occure if
A the magnitude of the two waves is the same
B the phase of the two waves is the same
C the magnitude is the same and the phase different is zero
D the magnitude is the same and the phase is
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