Railways NTPC (Technical Ability) Communication System / संचार तंत्र Question Bank

done Communication System Total Questions - 50

• question_answer1)
  The black and white or monochrome portion of the total colour signal is equivalent in all respects to present........... signals.
  A)
   black and white done clear
  B)
   red and blue done clear
  C)
   yellow and green            done clear
  D)
   red and yellow done clear
  View Solution play_arrow

• question_answer2)
  The illumination on screen when there is no broadcast or telecast, is known as
  A)
   raster    done clear
  B)
   contrast done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer3)
  The demodulation of sound signals in a TV receiver is accomplished by
  A)
   envelope detector           done clear
  B)
   discriminator done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer4)
  In TV receivers, the electron beam is deflected by
  A)
   electromagnetic technique done clear
  B)
   electrostatic technique done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer5)
  A primary colour differs from its complementary by a phase angle of
  A)
   \[180{}^\circ \]            done clear
  B)
   \[\frac{\pi }{3}\] done clear
  C)
   \[\frac{\pi }{4}\]                                    done clear
  D)
   \[\frac{\pi }{6}\] done clear
  View Solution play_arrow

• question_answer6)
  The linearity of a TV receiver can be checked by
  A)
   multiplier                      done clear
  B)
   vector gram done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer7)
  Equalizing pulses in TV are sent during
  A)
   vertical blanking done clear
  B)
   horizontal blanking done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer8)
  A total colour signal consists of
  A)
   one component  done clear
  B)
   two components done clear
  C)
   five components done clear
  D)
   three components done clear
  View Solution play_arrow

• question_answer9)
  A live programme is transmitted from location to TV station through
  A)
   cables               done clear
  B)
   wireless done clear
  C)
   antennas                       done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer10)
  Colour TV camera is essentially a combination of............... basic cameras.
  A)
   five                              done clear
  B)
   two done clear
  C)
   four                              done clear
  D)
   three done clear
  View Solution play_arrow

• question_answer11)
  For 51 cm size TV the voltage required for picture tube is the order of
  A)
   13 kV               done clear
  B)
   15 kV done clear
  C)
   17 kV               done clear
  D)
   25 kV done clear
  View Solution play_arrow

• question_answer12)
  Which of me following signals is not transmitted in colour TV?
  A)
   Q                                 done clear
  B)
   I done clear
  C)
   R                     done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer13)
  Which channel has the highest frequency range?
  A)
   Channel? done clear
  B)
   Channel 5 done clear
  C)
   All channels have same frequency range done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer14)
  The signal sent by the TV transmitter to ensure correct scanning in the receiver are called
  A)
   chrome             done clear
  B)
   sync done clear
  C)
   video                done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer15)
  The light is converted into video signals corresponding to the red, blue and green components of the............. picture.
  A)
   white                done clear
  B)
   black done clear
  C)
   red                               done clear
  D)
   original colour done clear
  View Solution play_arrow

• question_answer16)
  Which of the following conducts during fly back?
  A)
   Silicon diode damper      done clear
  B)
   Output stage done clear
  C)
   High voltage rectifier       done clear
  D)
   None for the above done clear
  View Solution play_arrow

• question_answer17)
  The output of the vertical amplifier applied to the yoke in a TV receiver, consists of
  A)
   a saw tooth voltage        done clear
  B)
   a saw tooth current done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer18)
  The method of modulation of sound in TV system in India is
  A)
   amplitude modulation done clear
  B)
   frequency modulation done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer19)
  Which of the following are secondary colours?
  A)
   All colours other than green, blue and red done clear
  B)
   Green, blue and red done clear
  C)
   White and black done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer20)
  In TV if three is no brightness but sound is normal, the trouble could be in
  A)
   horizontal oscillator        done clear
  B)
   vertical oscillator done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer21)
  A number of different colours can be formed by the combinations of colours in
  A)
   two colours                   done clear
  B)
   three colours done clear
  C)
   five colour                     done clear
  D)
   seven colours done clear
  View Solution play_arrow

• question_answer22)
  The fine tuning control in television receiver is
  A)
   a potentiometer done clear
  B)
   a variable capacitor done clear
  C)
   both [a] and [b] done clear
  D)
   anyone of the above done clear
  View Solution play_arrow

• question_answer23)
  In TV. system
  A)
   picture and sound are frequency modulated done clear
  B)
   picture and sound are amplitude modulated done clear
  C)
   picture is amplitude modulated while sound is frequency modulated done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer24)
  TV broadcasting system in India is as per CCIR
  A)
   system X          done clear
  B)
   system B done clear
  C)
   system A                      done clear
  D)
   system I done clear
  View Solution play_arrow

• question_answer25)
  The sound signal in video composite signal of TV is
  A)
   FSK                             done clear
  B)
   AM done clear
  C)
   FM                               done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer26)
  The three primary colours are
  A)
   red, orange and blue done clear
  B)
   red, blue and green done clear
  C)
   red, yellow and blue done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer27)
  The number of frames per second in TV system in India is
  A)
   25                                done clear
  B)
   80 done clear
  C)
   20                                done clear
  D)
   75 done clear
  View Solution play_arrow

• question_answer28)
  Which of the following will increase the antenna radiation efficiency?
  A)
   Providing insulation on conductor done clear
  B)
   Top loading of antenna done clear
  C)
   Both [a] and [b] done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer29)
  Which of the following is non-resonant antenna?
  A)
   The folded dipole done clear
  B)
   The end-fire array done clear
  C)
   The broad side array done clear
  D)
   Both [b] and [c] done clear
  View Solution play_arrow

• question_answer30)
  Scatter transmission is used at frequencies
  A)
   Very low frequency (VLF) done clear
  B)
   Ultra high frequency (UHF) done clear
  C)
   Very high frequency (VHP) only done clear
  D)
   Both [b] and [c] done clear
  View Solution play_arrow

• question_answer31)
  A helical antenna is used for satellite tracking because of its
  A)
   maneuver ability done clear
  B)
   broad width done clear
  C)
   good FBR done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer32)
  Which type of fading causes serious distortion of modulated signal?
  A)
   Polarization fading         done clear
  B)
   Absorption fading done clear
  C)
   Selective fading done clear
  D)
   Both [a] and [b] done clear
  View Solution play_arrow

• question_answer33)
  Which of the following antenna gives circular polarisation?
  A)
   Helical  done clear
  B)
   Dipole done clear
  C)
   Both [a] and [b] done clear
  D)
   None of these done clear
  View Solution play_arrow

• question_answer34)
  Which antenna does not depend on frequency?
  A)
   Log periodic antenna      done clear
  B)
   Yagi antenna done clear
  C)
   Both [a] and [b] done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer35)
  The frequency range for satellite communication is
  A)
   3000 to 30,000 MHz      done clear
  B)
   2000 to 25,000 MHz done clear
  C)
   45,000 to 65,000 MHz done clear
  D)
   75,000 to 1,25,000 MHz done clear
  View Solution play_arrow

• question_answer36)
  The gain of a current element is
  A)
   1.76 dB                        done clear
  B)
   2.52 dB done clear
  C)
   3.58 dB                        done clear
  D)
   7.25 dB done clear
  View Solution play_arrow

• question_answer37)
  The power gain of a half-wave dipole with respect to an isotropic radiator is
  A)
   6 dB                            done clear
  B)
   2.15 Db done clear
  C)
   7.25 dB                        done clear
  D)
   10.12 dB done clear
  View Solution play_arrow

• question_answer38)
  In order to receive a vertically polarized wave, the conductor of the dipole should be mounted
  A)
   at an angle of \[60{}^\circ \]      done clear
  B)
   horizontally done clear
  C)
   vertically           done clear
  D)
   at an angle of\[45{}^\circ \] done clear
  View Solution play_arrow

• question_answer39)
  A loop antenna is commonly used for
  A)
   direction finding done clear
  B)
   satellite communication done clear
  C)
   radar                done clear
  D)
   both [b] and [c] done clear
  View Solution play_arrow

• question_answer40)
  Which of the following is multiband high frequency receiving antenna?
  A)
   The folded dipole antenna done clear
  B)
   Log-periodic antenna done clear
  C)
   Square loop antenna done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer41)
  The gain factor of a half dipole is
  A)
    1.641  done clear
  B)
   1252 done clear
  C)
   3.25                             done clear
  D)
   7.95 done clear
  View Solution play_arrow

• question_answer42)
  The most important ionizing agents are
  A)
   ultra violet and\[\alpha \],\[\beta \], and\[\lambda \]radiations from the Sun as well as cosmic rays and meteors done clear
  B)
   infrared radiation being emitted by ground reactions occurring near the surface of earth done clear
  C)
   radiations and emissions by the polluting industries on the earth                                    done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer43)
                          Broadcasting antennas are generally                
  A)
   vertical type done clear
  B)
   horizontal type done clear
  C)
   both [a] and [b] done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer44)
  The night effect is most prominent in
  A)
   vertical antenna done clear
  B)
   ad cock antenna done clear
  C)
   loop antenna                 done clear
  D)
   both [a] and [b] done clear
  View Solution play_arrow

• question_answer45)
  D-layer of ionosphere extends approximately from
  A)
   95 to 150 km                done clear
  B)
   50 to 90 km done clear
  C)
   110 to 250 km   done clear
  D)
   135 to 270 km done clear
  View Solution play_arrow

• question_answer46)
  An antenna is
  A)
   capacitive coupled done clear
  B)
   inductive done clear
  C)
   both [a] and [b] done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer47)
  For aeroplane and navigation preferred frequency band is
  A)
   Very high frequency band done clear
  B)
   Very low frequency band done clear
  C)
   Ultra high frequency band done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer48)
  Anomalous propagation is due to
  A)
   troposcatter                   done clear
  B)
   super refractive duct done clear
  C)
   meteorological factors     done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer49)
  If frequency of modulated wave is less than frequency carrier wave, then input signal is
  A)
   Negative                       done clear
  B)
   Positive done clear
  C)
   Zero                             done clear
  D)
   Infinite done clear
  View Solution play_arrow

• question_answer50)
  Decrease in strength of signal is known as:
  A)
   tuning               done clear
  B)
   modulation done clear
  C)
   attenuation done clear
  D)
   amplification done clear
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