One Stop GATE Forum: GATE–Sample Questions-Electromagnetics

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   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

Author	Message
aparna Groupie Joined: 30Apr2007 Online Status: Offline Posts: 70	Topic: GATE–Sample Questions-Electromagnetics Posted: 27Nov2007 at 2:44am
	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 Post Resume:* Click here to Upload your Resume & Apply for Jobs

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