Question Bank - Telecommunication - Part IV

OBJECTIVE QUESTIONS.

CHOOSE THE CORRECT ANSWER 1) Number of PTOs eligible by Railway servant in a calendar year are A) 1 B) 2 C) 4 D) 6 ( C ) 2) Leave not due during entire service shall be limited to a maximum o A) 24 months B) 48 months C) 360 Days D) 4 months ( C ) 3) Group D staff retired after 20 years of service will get the following sets of passes A) 2 B) 1 C) 3 D) NIL ( B ) 4) Joining time eligible when the distance is below 1000 KM is A) 10 days B) 12 days C) 15 days D) Nil. ( A ) 5) The output stage of a practical amplifier is always - - - coupled A) R-C B) Transformer C) L.C ( B ) 6) R.C coupling is used for - - - amplification A) Voltage B) Current C) Power ( A ) 7) A Zener diode is operated in the - - - -region A) Breakdown Region B) Forward characteristic region ( A ) C) Reverse characteristic region 8) A Zener diode is used as - - - A) Rectifier B) Voltage regulator C) For both ( B ) 9) A Transistor has - - - PN junctions A) One B) Two C) Three ( B ) 10) Common collector arrangement is generally used - - - A) Impedance matching B) Voltage matching C) None of the above ( A ) 11) The most commonly used transistor circuit arrangement - - - A) Common base B) Common emitter C) Common collector ( B ) 12) The function of Transistor is to do - - - A) Rectification B) Amplification C) None of the above ( B ) 13) Amplifiers are coupled to - - - - A) Increase gain B) Reduce noise C) For both ( A ) 14) If three stage amplifiers has individual stage gain of 10 db, 5 db & 12 db then the total gain A) 600 db B) 7 db C) 27 db ( C ) 15) Output transformer is always a - - - - transformer A) Step down B) Step up C) Both ( A ) 16) Negative feed back reduces - - - - in amplifiers A) Distortion B) Stability C) None of the above ( A ) 17) Positive feed back used in - - - - A) Oscillators B) High gain amplifiers C) Rectifiers ( A ) 18) An Oscillator produces - - - oscillations A) Damped B) Undamped C) Both ( B ) 19) Tuned amplifiers are used for - - - - frequency amplification A) Audio B) Radio C) For both ( B ) 20) Detection is done in - - - - A) Radio transmitter B) Radio receiver C) None of the abov ( B) 21) Frequency modulation gives - - - noise A) More B) Less C) No noise ( B ) 22) Ground plane antenna are used for A) VHF B) UHF C) MW D) HF ( A ) 23) In AM wave, useful power is carried by - - - A) Carrier B) Side bands C) Both of the above ( B ) 24) Superhetrodyne principle provides selectivity at - - - stages A) RF B) IF C) None of the above ( B ) 25) A switch has - - - states A) One B) Two C) Three ( B ) 26) A circuit that generates square wave is called - - - A) Amplifiers B) Multi vibrators C) Flip-flop ( B ) 27) A FET is essentially a - - - - driven device A) Voltage B) Current C) Both ( A ) 28) A FET is a - - - transistor A) Bi-polar B) uni-polar C) None of the above ( A ) 29) An SCR has - - - PN junctions A) One B) Two C) Three ( C ) 30) If firing angle in SCR increases, output is - - - A) Increases B) Decreases C) No change ( B ) 31) An SCR is a - - - switch A) Uni-directional B) Bi-directional C) None of the above ( A ) 32) A Triac is a - - - power switch A) Uni-directional B) Bi-directional C) None of the above ( B ) 33) A Triac has - - - terminals A) One B) Two C) Three ( C ) 34) A UJT has - - - PN Junction A) One B) Two C) Three ( A ) 35) A Diac is an - - - switch A) AC B) DC C) Both the above ( A ) 36) ICs are generally made of - - - A) Silicon B) Germanium C) None of the above ( A ) 37) Binary means - - - Binary numbers have a base of 2 A) One B) Two C) Three ( B ) 38) The digits used in a binary number system are A) 0 & 0 B) 0 & 1 C) 1 & 1 ( B ) 39) A Byte is a string of - - - Bits A) 16 B) 8 C) 2 ( B ) 40) A typical Microcomputer have - - - registers in memory A) 4096 B) 2048 C) 65536 ( C ) 41) A Gate is a logic circuit with one or more inputs, but only - - - output A) One B) Two C) Three ( A ) 42) The - - - gate has one or more high inputs, produces high output A) NOT B) OR C) XOR ( B ) 43) Which is the logic gate, where all input signals must be high to get a high output A) AND B) OR C) NOT ( A ) 44) In a NOR gate all inputs must be - - - to get high output A) Low B) High C) None of the above ( A ) 45) A NAND gate is equivalent to an - - - gate followed by an inverter A) AND B) OR C) NOR ( A ) 46) What is ISDN? A) Integrated Services Data Network. ( D ) B) Internal services digital network. C) International services data networks. D) Integrated services digital network 47) For making outgoing calls, what is the tone heard when the telephone handset is lifted A) Busy tone B) Dial tone C) No tone D) Ring back tone ( B ) 48) What is the break down voltage suggested for lightening dischargers (LD) in the MDF of telephone exchanges A)230 V B)160 V C)300 V D)1600 V ( A ) 49) What is the basic function of a telephone exchange? A)Signaling B) Switching C) Control D) All the above ( D ) 50) What is the control system used in Electronic exchange A) Stored program control B) Wire logic control ( A ) C) Electromagnetic control D) None of the above 51) The maximum number of subscriber lines in C-DOT 128P RAX type exchange is A)104 B) 112 C)96 D)88 ( D ) 52) The duplication system employed for the PSU card of an electronic exchange is A)Passive standby B)Load sharing standby C)N+1 Redundancy ( B ) D)None of the above 53) is the object of earthing for telecommunication equipment A) to provide a return earth B) To provide safety against shack to the working person ( D ) C) to provide protection against unduly high voltages D) all the above 54) What is the earth electrode called ( C ) A) A wire buried in to the earth nearby the equipment B) An iron rod buried I to the earth near the equipment C) A metal plate electrically connected to the general mass of the earth D None of the above 55) What is the maximum limit of earth resistance for Telecom equipment A) 10 ohms B) 5 ohms C) 2 ohms D) 1 ohm ( D ) 56) How the telecom equipment is connected to the earth electrode ( A ) A) by using earthing lead B) by keeping the equipment close to the electrode C) by using capacitors D) None of the above 57) What are the materials used to prepare an efficient earth for telecom equipment ( A ) A) coke, crushed coal and common salt B) plastic waste, thermo coal and glass pieces C) wood saw dust, white cement and asbestos powder D) wax, petroleum jelly and castor oil 58) In Microwave station which lead of the charger is earthed A) negative B) positive C) None of the above ( B ) 59) The maximum number of way stations can be in a control section using 2- digit code are A) 60 B) 99 C) 100 D) 90 ( B ) 60) DTMF control equipment works on A) 24 Volts B) 12 Volts C) 48 Volts D) 230 Volts ( B ) 61) Nominal ringing period at way station is A) 4 seconds B) 8 seconds C) 12 seconds D) 1 minute ( A ) 62) No. of 20 watts loud speakers permitted to connect an 250 watt amplifierare ( C ) A ) 5 B) 15 C) 12 D) 20 63) Block circuits in RE area works on ( C ) A) MW patch B) VF quad C) PET quad D) Carrier quad 64) To increase the ampere hour capacity of secondary cells, the cells are to be connected in A) Series B) Parallel C) Series and Parallel D) One above the othe ( B ) 65) No. of cable pairs required for 4 wire E&M working are ( C ) A) One B) Four C) Three D) Six 66) Duplexer is used for ( D ) A To couple two different antennaes B) To prevent interference between two antennas C) To increase the speed of transmission D) To allow one antenna to be used for reception and transmission 67) Inverter convert ( B ) A) AC to DC B) DC to AC C) DC to DC D) AC to AC 68) For converting 2 wire to 4 wire the following is required ( C ) A) Low pass filter B) High Pass filter C) Hybrid D) All these 69) In EC socket the transformer used have the impedance ratio ( D ) A) 2:1 B) 1120 : 1120 C) 470 : 1120 D) 1120 : 600 70) In a hybrid transformer the loss is ( B ) A) 2 db B) 3db C) 4 db D) No loss 71) A power amplifier gives a gain of 3 db when the input is 1 W the output is: ( B ) A) 1.3W B) 2 W C) 3 W D) .3 W 72) Grid antenna is used in ( C ) A) MW B) VHF C) UHF D) HF 73) Hybrid transformer is used in the following electronic exchange card ( D ) A) LCC B) SPC C) TIC D) TGT 74) In electronic exchange the system software is written as ( D ) A) E PROM B) E2 PROM C) RAM D) ROM 75) Which of the electronic exchange card is not redundant. ( B ) A) X SC B) LCC C) PSU D) RGD 76) The processor used in a C DOT exchange is ( A ) A) 65 CO2 B) 8085 C) Z80 D) 8031 77) Control card used in C DOT exchange is ( D ) A) SPC B) TIC C) RCT D) All the above. 78) RE repeater are spaced at every ( B ) A) 17 KM B) 40 KM C) 60 KM D) 1860 M 79) The insertion loss of way station control telephone is ( C ) A) 3 db B) 2 db C) 0.2 db D) 0.5 db. 80) The charectristic impedance of PET quad pair is -------------- ( B ) A) 600 Ohms B) 470 Ohms C) 1120 Ohms 81) The loading coil section in RE cable is ( A ) A) 915 m B) 1830 m C) 530m 82) Which of the MW frequency spectrum is used for Railway administration trunks ( B ) A) 4125 4425 MHz B) 7125 7425 MHz C) 1200 1600 MHz 83) The size of RE cable having 2 PET and 12 VF quad is represented as ( C ) A) 2 + 0 + 12 B) 0 + 2 + 12 C) 0 + 12 + 2 D) 0 + 14 84) Float charge voltae adjusted per cell in ( A ) A) 2.16 V B) 2.4 V C) 1.8 V 85) Beta in grounded emitter circuit is very high due to ( B ) A) base current is equal to collector current B) base current in small compared to collector current C) base current is higher than collector current 86) A metallic sheath is provided in RE cable to ( B ) A) to reduce cross-talk B) to reduce induce voltage C) to reduce weight of the cable 87) In RE cable the insulation resistance will be ( C ) A) less than 10 mega ohms B) more than 10 mega ohms C) above 20 mega ohms 88) Loud Speakers are always connected in parallel on ( C ) A) Voltage Matching B) Impedance Matching C) Both of them D) None of them Read Also -  Q BANK - TELECOMMUNICATION - PART I TELECOMMUNICATION - PART II & III ALSO SEE - MORE RELATED FOR RAILWAY EMPLOYEE