Paper : BSNL JTO Model Test Paper For 2009 ExaminationsIf the voltage applied across a capacitance is triangular in waveform then the waveform of the current isa) Triangularb) Trapezoidalc) Sinusoidald) RectangularAnswer: d.

One of the following statement which is true for relative dielectric constant isa) It is dimensionlessb) It is not equal to unity for vacuumc) It’s value for all substances is less than oned) NoneAnswer: a

Pure metals generally havea) high conductivity and low temperature coefficientb) high conductivity and large temperature coefficientc) low conductivity and zero temperature coefficientd) low conductivity and high temperature coefficientAnswer:a

For small size, high frequency coils, the most common core material isa) Airb) Ferritec) Powdered iond) SteelAnswer: a

For an abrupt junction Varactor diode, the dependence of device capacitance (C) on applied reverse bias (V) is given bya) C a V1/3b) C a V-1/3c) C a V1/2d) C a V-1/2Answer: a

A superconductor is aa) A material showing perfect conductivity and Meissner effect below a critical temperatureb) A conductor having zero resistancec) A perfect conductor with highest dimagnetic susceptibilityd) A perfect conductor which becomes resistive when the current density through it exceeds a critical valueAnswer: 2

When a semiconductor based temperature transducer has a temperature coefficient of –2500 mV/0C then this transducer is indeed aa) Thermistorb) Forward biased pn junction diodec) Reverse biased pn junction dioded) FETAnswer: b

The location of lightning arrestor isa) Near the transformerb) Near the circuit breakerc) Away from the transformerd) NoneAnswer: a

Time constant of an RC circuit increases if the value of the resistance isa) Increasedb) Decreasedc) Neither a nor bd) Both a and bAnswer: a

Intrinsic semiconductors are those whicha) Are available locallyb) Are made of the semiconductor material in its purest fromc) Have more electrons than holesd) Have zero energy gapsAnswer: b

The primary control on drain current in a JFET is exerted bya) Channel resistanceb) Size of depletion regionsc) Voltage drop across channeld) Gate reverse biasAnswer: dThe electrical conductivity of metals which is expressed in ohm-1 m-1 is of the order ofa) 1010b) 105c) 10-4d) 10-6Answer: bWhen biased correctly, a zener diodea) acts as a fixed resistanceb) has a constant voltage across itc) has a constant current passing through itd) never overheatsAnswer: bThe current amplification factor adc is given bya) IC/IEb) IC/IBc) IB/ICd) IB/ICAnswer: a

Compared to bipolars, FETs havea) high input impedanceb) low input impedancec) same input impedanced) noneAnswer: a

The source-drain channel of JFET isa) ohmicb) bilateralc) unilaterald) both a and bAnswer: d1. The coupling coefficient between two air core coils depends on(A) Mutual inductance between two coils only(B) Self-inductances of the two coils only

(C) Mutual inductance and self-inductances of the two coils(D) None

Ans-C

2. Which of the following is the incorrect statement for a parallel plate capacitor which is being charged-?(A) Energy stored in the capacitor does not enter it through the connecting wire through the space around the wires and plates of capacitor.(B) Rate at which energy flows into this volume is equal to the integration of the poynting vector over the boundary of the volume between the plates.(C) The poynting vector points everywhere radially outward of the volume between plates.(D) The poynting vector points everywhere radially in to the volume between the plats.

Ans- C

3. An SCR can only be turned off via it’s(A) Cathode(B) anode(C) gates(D) none

Ans- B

4. Gold is diffused into silicon PN junction devices to(A) Increase the recombination rate(B) Reduce the recombination rate(C) Make silicon a direct gap semiconductor(D) Make silicon semi-metal

Ans- B

5. How many links can be formed with n nodes and b branches-?(A) (b+n) links(B) (b – n +1) links(C) (b -n-1) links(D) (b + n + 1) links

Ans- B

6. When a network has 10 nodes and 17 branches in all then the number of node pair voltages would be(A) 7(B) 9(C) 10(D) 45

Ans- B

7. What is the potential energy of an orbiting electron in any atom-?(A) Always positive(B) Always negative

(C) Sometime positive, sometime negative(D) Numerically less than its kinetic energy.

Ans- B

8. Barrier potential in a P-N junction is caused by(A) thermally generated electrons and holes(B) diffusion of majority carriers across the junction(C) migration of minority carriers across the junction(D) flow of drift current.

Ans- C

9. NPN transistor is properly biased then the electrons from the emitter-(A) Recombine with holes in the base(B) Recombine in the emitter itself(C) Pass through the base to the collector(D) Are stopped by the junction barrier

Ans- C

10. A Unipolar Junction Transistor can(A) be triggered by any one of its three terminals(B) Not be triggered(C) Be triggered by two of its three terminals only(D) Be triggered by all of its terminals only.

Ans- C

11. When the graph of a network has six branches with three tree branches then the minimum number of equations required for the solution of the network is(A) 2(B) 3(C) 4(D) 5

Ans- B

12. as a network contains only independent current sources and resistors then if the values of all resistors are doubled then the values of the node voltages are(A) Will become half (B) Will remain unchanged(C) Will become double(D) Cannot be determined unless the circuit configuration and the values of the resistors are known.

Ans- C

13. A iron cored choke is a(A) Linear and active device(B) Nonlinear and passive device(C) Active device only(D) Linear device only

Ans- B

14. Poynting vector wattmeter is based on(A) See beck effect(B) Ferranti effect(C) Induction effect(D) Hall effect

Ans- C

15. Which one of the following is not a transducer?(A) Thermocouple(B) Piezoelectric pick-up(C) Photo voltaic cell(D) LCD.

Ans- D

16. The term which used to denote a static device that converts ac to dc, dc to ac, dc to dc or ac to ac is(A) Converter system(B) Inverter(C) Chopper(D) Thyristor

Ans- A

17. When a dipole antenna of 1/8 length has an equivalent total resistance of 1.5 Watt then the efficiency of the antenna is(A) 0.89159%(B) 8.9159%(C) 89.159%(D) 891.59%

Ans- C

18. The maximum frequency deviation in commercial FM broadcasting is normally-(A) 5 KHz(B) 15 KHz(C) 75 KHz (D) 200 KHz

Ans- C

19. Weins Bridge is used for measurement of frequency in the applied voltage waveform is measurement of frequency in the applied voltage waveform is(A) Sinusoidal(B) square(C) rectangular(D) triangular

Ans- A

20. Strain gauge is(A) Not a transducer(B) An active transducer(C) Not an electronic instrument

Ans- B

21. A high Q coil has any one of the property from the following-(A) Large band width(B) High losses(C) Low losses(D) Flat response

Ans- B

22. In the case of an instrument reading of 8.3 V with a 0 to 150 voltmeter having a guaranteed accuracy of 1% full scales reading, the percentage limiting error of the instrument is-(A) 1.810%(B) 0.181%(C) 12.45%(D) 0.0018%

Ans- C

23. The ‘h’ parameter equivalent circuit of a junction transistor is valid for(A) High frequency, large signal operation(B) High frequency, small signal operation(C) Low frequency, large signal operation.

Ans- C

24. A system is causal if the output of any time depends only on(A) Values of input in the past and in the future(B) Values of input at that time and in the past(C) Values of input at that time and in the future(D) None

Ans- B

25. The electrons escape from the hot metal surface because(A) Of change of state from metal to gas due to heat.(B) Of change of state from gas to metal(C) The energy supplied is greater than the work function(D) The energy is greater than Fermi level

Ans- C

26. The device used for detection in radio receivers is(A) amplifier(B) Triode(C) Diode(D) Transistor

Ans- C

27. The negative point in a circuit of a full wave rectifier is(A) cathode(B) Anode(C) The central tap on the high voltage secondary(D) Plate.

Ans- C

28. Negative feedback amplifier has a signal corrupted by noise as its input. The amplifier will(A) Amplify the noise as much as the signal(B) Reduce the noise(C) Increase the noise(D) Not effect the noise

Ans- B

29. Quantum effects have to be taken into account in determining the properties of materials if(A)EF = 3/2kT(B) EF < 3/2kT(C) EF > 3/2kT(D) EF >> 3/2kT

Ans-(D)

30. The difference between the number of atoms in a unit cell of a bcc crystal and an fcc crystal is(A)1(B)2(C)4(D)6

Ans-(B)

31. For an insulating material, dielectric strength and dielectric loss should be respectively(A) High and high(B) Low and high(C) High and low(D) Low and low

Ans-C

32. Which of the following materials are piezoelectric-?(A)Mica and quartz(B)Mica, barium titanate and quartz(C)Mica and diamond(D)Barium titanate and quartz

Ans-D

33. A 1ms pulse can be stretched to 1 s pulse by using(A)an astable multivibrator(B)a monostable multivibrator(C)a bistable multivibrator(D)a Schmitt trigger circuit

Ans-B

34. A tunnel diode is(A)High resistivity p-n junction diode(B)A slow switching device(C)An amplifying device(D)A very heavily doped p-n junction diode

Ans- D

35.What is the typical value for the ratio of current in a p-n junction diode in the forward bias and that in the reverse bias?(A) 1(B) 10(C) 100(D) 1000

Ans- D

36. Which one of the following is not LED material?(A) GaAs(B) GaP(C) SiC(D) SiO2

Ans-D

37. A vertical wire of length carries a current of 1A at 10MHz.The total radiated power is nearly(A) 0.13W(B) 0.88W(C) 7.3W(D) 73W

Ans-B

38.The radiation field of an antenna at a distance r varies as(A) 1/r(B) 1/r2

(C) 1/r3

(D) 1/r4

Ans- A

39.The common mode error voltage in a DVM can be eliminated by using at its input(A) a differential amplifier(B) a wide band amplifier(C) a tuned amplifier(D) a low-pass filter

Ans-A

40. Very small displacements are effectively measured using(A) LVDT(B) Strain gauge(C) Thermistor(D) Tachogenerator

Ans-A

PART 241. Satyameva Jayathe’ have been taken from which of the following-(A) Vedas(B) Bhagavad Gita(C) Mundaka Upanishada(D) Mahabharatha(E)None of these

Ans- A

42. Neutron bomb was firstly developed in which of the countries-(A) USA(B) USSR(C) China(D) Pakistan

Ans- A

43.”Kathakali” dance is connected with(A) Kerala(B) Rajasthan(C) Uttar pradesh(D) Tamil Nadu

Ans- A

44. The term “Ashes” is associated with(A) Hockey  (B) Cricket(C) Soccer(D) None of these.

Ans- B

45. Which of the following is a specimen of The Kailash Temple at Ellora-(A) Gupta architecture(B) Rashtrakutlas architecture(C) Chalukya architecture(D)Chola architectureAns- D46. When the two Houses of Parliament differ regarding a Bill then the controversy is solved by(A) Joint sitting of the two Houses(B) President of India(C) Prime Minister of India(D) BY a special committee for the purpose

Ans- C

47.Which of these is not work of kalidasa?(A) Meghdood(B) Reghuvansha(C) Sariputra Prakarma(D) Ritushamhara

Ans- D

48. Amir Khusro was the famous poet and aesthete of(A) Akbar the Grest(B) Mahmud Ghaznvi(C) Snah Jahan(D) Alauddin Khilji

Ans- A

49. With the beginings of space travel, we entered a new era of-(A) Era of great history(B) List

(C) Book(D) Year

Ans- A

50. An though it mourns the death of someone, need not be sad.(A) Funny poem(B) Newspaper article(C) Othodox talk(D) Elegy

Ans- D

51. Stare:glance so gulp: -(A) Sip(B) Tell(C) Salk(D) Admire

Ans- A

52. He hardly works means(A) The work is hard(B) He is hard(C) The work is easy(D)He work very little.

Ans- D

53. Whats the opposite of word for pulchritude(A) Antipathy(B) unsightliness(C) inexperience(D) languorAns- B54. Nanometre is which part of metre-(A) Millionth(B) Ten Millionth(C) Billionth(D) Ten billionths

Ans- B

55. Malaria affects-(A) Liver(B) Spleen(C) Intestine(D) Lungs

Ans- B

56. Sindhu Rakshak is a an-(A) Aircraft carrier(B) Submarine(C) Multiple purpose fighter(D) Anti-aircraft gun

Ans- D

57.” Dada Saheb Phalke Award” is associated with which subject-(A) Best film director(B) Best musician

(C) Best documentary(D) Best work relating to promotion of Indian film industry

Ans- C

58. Branch of mathematics,Calculus was developed by whom-(A) Arybhatta(B) Newton(C) Einstein(D) Archimedes

Ans- C

59. Kanha Part situated in which state-(A) M.P(B) U.P(C) Assam(D) W.Bengal

Ans- B

60. Which day is observed as Human Rights Day?(A) 24th October(B) 4th July(C) 8th August(D) 10th December

Ans- A

BSNL JTO 2009 Question Paper with AnswerPART I1. Modern capacitors which have high capacitance insmall size use a dielectric of

(A) paper (B) rubber (C) ceramic (D) Mylar

2. The Maximum spectral response of thegermanium and silicon is in the(A) infrared region (B) ultraviolet region (C) visibleregion (D)x-ray region

3. For an insulating material, dielectric strength anddielectricloss should be respectively(A) high and high (B) low and high (C) high and low (D)low and low.

4. In a distortion factor meter, the filter at the frontend is used suppress(A) odd harmonics (B) even harmonics (C)fundamental component (D) dc component

5. The coefficient of coupling between two air corecoils depends on(A) mutual inductance between two coils only (B)self inductances of the two coils only (C) mutual inductance and self inductances of the twocoils (D) none

6. For a parallel plate capacitor which is being charged out of the following the incorrect

statement is(A) Energy stored in the capacitor does not enter it through the connecting wire through thespace around the wires and plates of capacitor.(B) Rate at which energy flows into this volume is equal to the integration of the poyntingvector over the boundary of the volume between the plates.(C) The poynting vector points everywhere radially outward of the volume between plates.(D) The poynting vector points everywhere radially in to the volume between the plates.

7. The presence of alkali oxides in alumino silicate ceramics is likely to result in dielectricbreakdown due to(A) Polarization (B) Conductivity (C) Structural homogeneties (D) Ionization

8. Which of the following will serve as a donor impurity in silion(A) Boron (B) Indium (C) Germanium (D) Antimony

9. Electrical contact materials used in switches, brushes and relays must possess(A) high thermal conductivity and high melting point (B) Low thermal conductivity and lowmelting point (C) High thermal conductivity and low melting point (D) Low thermalconductivity and high melting point.

10. An SCR can only be turned off via it’s(A) cathode (B) anode (C) gates (D) none

11. Gold is often diffused into silicon PN junction devices to(A) increase the recombination rate (B) reduce the recombination rate(C) make silicon a direct gap semiconductor (D) make silicon semi-metal

12 With n nodes and b branches a network will have(A) (b+n) links (B) b – n +1 links (C) b -n-1 links (D) b + n + 1 links

13. When a network has 10 nodes and 17 branches in all then the number of node pairvoltages would be(A) 7 (B) 9 (C) 10 (D) 45

14. In any atom the potential energy of an orbiting electron is(A) always positive (B) always negative(C) sometime positive, sometime negative (D) numerically less then its kinetic energy.15. A delition MOSFET differs from a JFET in the sense that it has no(A) channel (B) gate (C) P-N junctions (D) substrate16. The advantage of a semiconductor strain gauge cover the wire round strain guage is that(A) it is more sensitive (B) it is more linear (C) it is less temperature dependent (D) it’s costis low

17. Barrier potential in a P-N junction is caused by

(A) thermally generated electrons and holes (B) diffusion of majority carriers across thejunction(C) migration of minority carriers across the junction (D) flow of drift current.

18. When an NPN transistor is properly biased then most of the electrons from the emitter(A) recombine with holes in the base (B) recombine in the emitter itself(C) pass through the base to the collector (D) are stopped by the junction barrier

19. The deplition voltage for silicon diode at m0 bias is(A) 0.5 volt (B) 0.3 volt (C) 0.7 volt (D) 1.1 volt

20. A UJT can(A) be triggered by any one of it’s three terminals (B) not be triggered(C) be triggered by two of its three terminal only (D) be triggered by all of its terminals only.

21. The energy of electric field due to a spherical charge distribution of radius r and informcharge density in vacuum is

23. When a short grounded vertical antenna has a length L which is 0.05 1 at frequency f andif it’s radiation resistances at f is R Ohms, then its radiation resistance at a frequency 2f willbe(A) R/2 O (B) R O (C) 2R O (D) 4R O

24. In a cylindrical cavity resonator, the two modes which are degenerate would include(A) TE111 and TM111 (B) TE011 and TM011 (C) TE022 and TM111 (D) TE111 and TM011

25. When an antenna of input resistance 73 ohm is connected to a 50-ohm line and if thelosses are ignored then its efficiencywill be nearly(A) 0.19 (B) 0.81 (C) 0.97 (D) 1.19

26.The transformer utilization factor of full wave bridge rectifier is(A) 0.812 (B) 0.286 (C) 0.693 (D) 0.78227. When a dominant mode wave guide not terminated in its characteristic impedance isexcited with a 10 GHZ signal then ifd is the distance between two successive minima of the standing wave in the guide then(A) d = 1.5 cm (B) d is less then 1.5 cm (C) d is greater then 1.5 cm (D) d = 3cm

28. A two port network having a 6 dB loss will give(A) an output power which is one – quarter of the input power (B) an output power which isone-half of the input power(C) an output voltage which is 0.707 of the input voltage. (D) an output power which is 0.707of the input power.

29. While transporting a sensitive galvanometer(A) the terminals are kept shorted (B) critical damping resistance is connected across theterminals(C) the terminals are kept open circuited (D) it does not matter as to what is connectedacross the terminals.30. A T type attenuator is designed for an attenuation of 40 dB and terminating resistance of75 ohms.Which of the following values represent full series arm R1 and shunt arm R2?1.R1 = 147 O 2. R1 = 153 O 3. R1 = 1.5 O 4. R1= 3750 O(A) 1 and 3 (B) 1 and 4 (C) 2 and 3 (D) 2 and 4

31. For a transmission line, the characteristic impedance with inductance 0.294 μH/m andcapacitance 60pF/m is(A) 49 O (B) 60 O (C) 70 O (D) 140 O

32. When the graph of a network has six branches with three tree branches then theminimum number of equations required for the solution of the network is(A) 2 (B) 3 (C) 4 (D) 5

33. Consider the following statement for a 2-port network1. Z11 =Z22 2. h12 = h21 3.Y12 = -Y21 4.BC – AD = -1 then the network is reciprocal if andonly if(A) 1 and 2 are correct (B) 2 and 3 are correct (C) 3 and 4 are correct (D) 4 alone is correct.

34. As a network contains only independent current sources and resistors then if the values ofall resistors are doubled then the values of the node voltages are(A) will become half (B) will remain unchanged(C) will become double (D) cannot be determined unless the circuit configuration and thevalues of the resistors are known.

35. A iron cored choke is a(A) Linear and active device (B) Non linear and passive device (C) Active device only (D)Linear device only

36. Poynting vector watt-meter is based on(A) Seebeck effect (B) Ferranti effect (C) Induction effect(D) Hall effect

37. Which one of the following is not a transducer in the true sense?(A) Thermocouple (B) Piezoelectric pick-up (C) voltaic cell (D) LCD.38. The term used to denote a static device that converts ac to dc, de to ac, dc to dc or ac toac is(A) Converter system (B) Inverter (C) Chopper (D) Thyristor39. When a dipole antenna of 1/8 length has an equivalent total resistance of 1.5 Watt thenthe efficiency of the antenna is(A) 0.89159% (B) 8.9159% (C) 89.159% (D) 891.59%

40. In commercial FM broadcasting, the maximum frequency deviation is normally(A) 5 KHz (B) 15 KHz (C) 75 KHz (D) 200 KHz41. Weins bridge is used for measurement of frequency in the applied voltage waveform ismeasurement of frequency in the applied voltage waveform is(A)sinusoidal (B) square (C) rectangular (D) triangular42. Strain gauge is(A) not a transducer (B) an active transducer (C) not an electronic instrument43. A high Q coil has(A) large band width (B) high losses (C) low losses (D) flat response44. In the case of an instrument reading of 8.3 V with a 0 to 150 voltmeter having aguaranteed accuracy of 1% full scalereading, the percentage limiting error is(A) 1.810% (B) 0.181% (C)12.45% (D) 0.0018%45. The ‘h’ parameter equivalent circuit of a junction transistor is valid for(A) High frequency, large signal operation (B) High frequency, small signal operation (C) Lowfrequency, large signal operation.

46. A system is causal if the output of any time depends only on(A) Values of input in the past and in the future (B) Values of input at that time and in thepast(C) Values of input at that time and in the future (D) none

47. Form the hot metal surface electrons escape because(A) of change of state from metal to gas due to heat. (B) of change of state from gas tometal(C) the energy supplied is greater than the work function (D) the energy is greater than FermiLevel

48. The most common device used for detection in radio receivers is(A) (B) triode (C) diode (D) transistor

49. In a full wave rectifier the negative point in a circuit is(A) cathode (B) anode (C) The central tap on the high voltage secondary (D) plate.

50. Negative feedback amplifier has a signal corrupted by noise as its input. The amplifier will(A) Amplify the noise as much as the signal (B) Reduce the noise (C) Increase the noise (D)Not effect the noisePART – II

51. It is an unidirectional device that blocks the current flow from cathode to anode(A) SCR (B) PCR (C) (D) DCR

52. An ideal constant current source is connected in series with an ideal constant voltagesource. Considering together thecombination will be a

(A) constant voltage source (B)constant current source(C) constant voltage and a constant current source or a constant power source. (D) resistance

53. Anode current in an thyristor is made up of(A) electrons only (B) electrons or holes (C) electrons and holes (D) holes only

54. For a pulse transformer, the material used for its core and the possible turn ration fromprimary to secondary are respectively(A) ferrite : 20 : 1 (B) laminated iron : 1 :1 (C) ferrite : 1 : 1 (D) powered iron : 1: 1

55. A converter which can operate in both 3 pulse and 6 pulse mode is a(A) 1 phase full converter (B) 3 phase half wave converter (C) 3 phase semi converter (D) 3phase full converter.

56. A single phase CSI has capacitor C as the load. For a constant source current, the voltageacross the capacitor is(A) square wave (B) triangular wave (C) step function (D) pulsed wave

57. a single phase full wave midpoint thyristor converter uses a 230/200V transformer withcentre tap on the secondary side. The P.I.V per thyristor is(A) 100V (B)141.4V(C)200V (D)282.8V

58. In dc choppers for chopping period T, the output voltage can be controlled by FM byvarying(A) T keeping Ton constant (B) Ton keeping T constant(C) Toff keeping T constant (D) None of the above

59.An ideal consist of(A) Very small output resistance (B) Zero Internal resistance(C) Very large input resistance (D) Very large output resistance

60. The linearity error for a digital input is indicated by(A) ? (B) gamma (C) ? (D) e61. In the 8421 BCD code the decimal number 125 is written as(A) 1111101 (B) 0001 0010 0101 (C) 7D (D) None of the bove62. Match the given feedback circuit with its proper nomenclaturesA) Current series feedback (B) Current shunt feedback(C) Voltage series feedback (D) Voltage shunt feedback

63. Class A amplifier is used when(A) No phase inversion is required (B) Highest voltage gain is required(C) dc voltages are to be amplified (D) Minimum distortion is desired.

64. Identity the correct match for the given transister(A) Enhancement type P channel MOSFET (B) Depletion type N channel MOSFET(C) Enhancement type N channel MOSFET (D) Depletion type P channel MOSFET

65. In case a signal band limited to fermimeter is sampled at a rate less than 2 fermimeter,the constructed signal willbe(A) Distortion-less (B) Small in amplitude (C) Having higher frequencies suppressed (D)Distorted

66. IC which has quad 2 input AND gates(A) 7411 (B) 7404 (C)7400 (D) 7408

67. Registers in which data is entered or taken out in serial form are referred as(A) left shift register (B) right shift register (C) shift registers (D) none of the above

69. Read the following(i) Routh Herwitz’s criterion is in time domain(ii) Root locus plot is in time domain(iii) Bode plot is in frequency domain(iv) Nyquist criterion is in frequency domain.(A) 2,3 and 4 are correct (B) 1,2 and 3 are correct (C) 3 and 4 are correct (D) all four areCorrect

70. Register and counters are similar in the sense that they both(A) count pulses (B) store binary operation (C) shift operation

(C) made from an array of flip flops and gates integrated on a single chip.

71. In D/A converter, the resolution required is 50mv and the total maximum input is 10v.The number of bits required is(A) 7 (B) 8 (C) 9 (D) 200

72. On different unit impulse function results in(A) Unit parabolic function (B) Unit triplet (C) Unit doublet (D) Unit ramp function

73. … watt of power is received from sun per m2 surface area of a geosynchronous satellite(A) 100 (B) 500 (C) 2000 (D) 1000

74. The ripple factor in an LC filter.(A) Increases with the load current (B) Increases with the load resistance(C) Remains constant with the load current (D) Has the lowest value

75. In different parts of the country identical telephone numbers are distinguished by their(A) Language digits (B) Access digits (C) Area codes (D) Central office codes

76. Amplitude modulation is used for broadcasting because

(A) it is move noise immune than other modulation systems(B) compared with other systems it requires less transmitting power(C) its use avoids receiver complexity(D) no other modulation system can provide the necessary bandwidth for high fidelity.

77. The maximum phase shift that can be provided by a lead compensator with transferfunction.(A) 15o (B) 45o (C) 30o (D) 60o

78. The correct sequence of steps required to improve system stability is(A) Insert derivative action, use negative feedback, reduce gain(B) Reduce gain, use negative feedback, insert derivative action(C) Reduce gain, insert derivative action, use negative feedback(D) Use negative feedback, reduce gain, insert derivative action,

79. Identity slope change at w = 10 of the magnitude v/s frequency characteristic of a unityfeedback system with the following open-loop transfer function.A -80 dB/dec to -60 dB/decB 40 dB/dec to 20 dB/decC 20 dB/dec to -40 dB/decD 40 dB/dec to -20 dB/dec

80. In the feedback control system the loop transfer function is given by KNumber of asymptotes of its root lociisA. 1 B. 2 C. 3 D. 481. In a closed – loop transfer functionA. ±j228 B. ±j2.28 C. ±j1.14 D. j114

82. Considering the following statement : In a magic tee1. the collinear arms are isolated from each other2. one of the collinear is isolated from the E-arm3. one of the collinear arm is isolated from the H-arm4. E-arm and H-arm are isolated from each other. Of these statements(A) 1 and 2 are correct (B) 1 and 3 are correct (C) 1 and 4 are correct (D) 2 and 3 are correct.83. In 1965 first geostationary was launched called(A) ANIK (B) EARLY BIRD (Intel sat – 1) (C) WESTAR (D)MOLNIYA

84. When A = 0., B = 0, C = 1 then in two input logic gate we get gate(A) XOR gate (B) AND gate (C) NAND gate (D) NOR gate

85. In a radio receiver the IF amplifier(A) is tuned above the stations incoming frequency (B) amplifies the output of local oscillator(C) is fixed tuned to one particular frequency (D) can be tuned to various isolate frequencies

86. A duplexer is used to(A) Couple two antennas to a transmitter without interference(B) isolate the antenna from the local oscillator(C) prevent interference between two antennas connected to a receiver(D) use an antenna for reception or transmission without interference.

87. Boolean algebra is based on(A) numbers (B) logic (C) truth (D) symbols

88. The amplifiers following the modulated stage in a low level modulation AM system be(A) linear amplifier (B) harmonic generators (C) class C (D) class untunedAmplifiers

89. In a radar system maximum unambiguous range depends on(A) maximum power of the transmitter (B) pulse repetition frequency(C) width of the transmitted pulse (D) sensitivity of the radar receiver.

90. In composite video waveform the function of the serrations, is to(A) equalize the charge in the integrator before the start of vertical retrace(B) help vertical synchronization (D) simplify the generation of the vertical sync pulse

91. The frequency range 30MHz – 300MHz is(A) medium frequency (B) very high frequency (C) super high frequency (D) Infrared frequency92. Which wave cannot exist inside wave guide(A) TE (B) TM (C) TEM (D) HE

93.Ionosphere layer of earth is situated at(A) upto 18 kms from earth (B) from 18 to 70 km (C) 70 to 500 km (D) above 500km

94. A two cavity klystron tube is a(A) velocity modulated tube (B) frequency modulated tube(C) Amplitude modulated tube (D) simple triode

95. As the thermal noise get doubled due to the increase in a resistance the noise power get.(A) doubled (B) quadruped (C) unchanged (D) halved.

96.Which one is a cross field tube(A) Klystron (B) Reflex Klystron (C) Magnetron (D) TWT

97. The degree of coupling depends(A) size of hole (B) location of holes (C) size and location of holes (D) not depend on size orlocation of hole

98. The thermal noise depends on(A) direct current through device(B) resistive component of resistance(C) reactive component of impedance(D) load to connected.

99. The charge on a hole is(A) 1.6 x 10-9 (B) 1.6 x 10-19 (C) 1.6 x 101 (D) 1.6 x 1020

100. Intel’s 8085 microprocessor chip contains(A) seven 8 bit registers (B) 8 seven bits registers (C) seven 7 bit registers (D) eight 8 bitregisters.

PART III

101. The words ‘Satyameva Jayathe’ have been taken from(A) Vedas (B) Bhagavad Gita (C) Mundaka Upanishada (D) Mahabharatha (E) None of these

102. Which of the following countries was the first to develop a neutron bomb?(A) USA (B) USSR (C) China (D) Pakistan

103. “Kathakali” dance is connected with(A) Kerala (B) Rajastan (C) Uttar pradesh (D) Tamil Nadu

104. The term “Ashes” is associated with(A) Hockey (B) Cricket (C) Soccer (D) None of these.

105. The Kailash Temple at Ellora is a specimen of(A) Gupta architecture (B) Rashtrakutlas architecture (C) Chalukya architecture (D) CholaArchitecture

106. When the two Houses of Parliament differ regarding a Bill then the controversy is solvedby(A) Joint sitting of the two Houses(B) President of India(C) Prime Minister of India(D) BY a special committee for the purpose

107. Which of the following is not work of kalidasa?(A) Meghdood (B) Reghuvansha (C) Sariputra Prakarma (D) Ritushamhara

108. Amir Khusro was the famous poet and aesthete of(A) Akbar the Grest (B) Mahmud Ghaznvi (C) Snah Jahan (D) Alauddin Khilji109. With the beginings of space travel, we entered a new(A) Era of great history (B) List (C) Book (D) Year110. An though it mourns the death of someone, need not be sad.(A) Funny poem (B) Newspaper article (C) Othodox talk (D) Elegy

111. If stare is glance so gulp is(A) Sip (B) Tell (C) Salk (D) Admire

112. He hardly works means(A) The work is hard (B) He is hard (C) The work is easy (D) He work very little.

113. Give the opposite word for pulchritude(A) antipathy (B) unsightliness (C) inexperience (D) languor

114. Nanometre is ……. part of metre(A) MIllionth (B) Ten Millionth (C) Billionth (D) Ten billionth

115. Malaria affects(A) Liver (B) Spleen (C) Intestine (D) Lungs

116. Sindhu Rakshak is a /anA) Aircraft carrier (B) Submarine (C) Multiple purpose fighter (D) Anti-aircraft gun

117. With which subject is “Dada Saheb Phalke Award” associated.(A) Best film director(B) Best musician(C) Best documentary(D) Best work relating to promotion of Indian film industry

118. Who developed the branch of mathematics known as Calculus?(A) Arybhatta (B) Newton (C) Einstein (D) Archimedes

119. In which state in Kanha Part situated?(A) M.P (B) U.P (C) Assam (D) W.Bengal

120. Which day is observed as Human Rights Day?(A) 24th October (B) 4th July(C) 8th Auguest (D) 10th December

ANSWERS:

1. (C) 2. (B) 3. (C) 4. (C) 5.(C) 6. (C) 7.(B) 8. (D) 9. (A) 10.(B)11. (B) 12. (B) 13.(B) 14. (B) 15.(C) 16. (A) 17.(C) 18. (C) 19. (C)20. (C) 21. (C) 22.(B) 23. (D) 24.(D) 25. (B) 26.(B) 27. (A) 28. (A)29. (B) 30. (A) 31.(C) 32. (B) 33.(D) 34. (C) 35.(B) 36. (C) 37. (D)38. (A) 39. (C) 40.(C) 41. (A) 42.(B) 43. (C) 44.(C) 45. (C) 46. (B)47. (C) 48. (C) 49.(C) 50. (B) 51.(A) 52. (B) 53.(C) 54. (C) 55. (C)56. (B) 57. (D) 58.(A) 59. (B) 60.(D) 61. (A) 62.(A) 63. (D) 64. (B)65. (D) 66. (D) 67.(C) 68. (D) 69.(D) 70. (D) 71.(B) 72. (C) 73. (D)74 (D) 75. (C) 76.(C) 77. (C) 78.(D) 79. (A) 80.(D) 81. (A) 82. (C)83. (C) 84. (C) 85.(C) 86. (C) 87.(B) 88. (C) 89.(B) 90. (C) 91. (B)92. (C) 93. (C) 94.(A) 95. (C) 96.(C) 97. (B) 98.(B) 99. (B) 100. (A)101. (A) 102. (A) 103.(A) 104. (B) 105.(D) 106. (C) 107.(D) 108. (A)109. (A) 110. (D) 111. (A) 112. (D) 113.(B) 114. (B) 115.(B) 116. (D)117. (C) 118. (C) 119.(B) 120. (A).

BSNL JTO Examination Solved Model Test Paper

(Part-3)

Mark out transferred electron device in the following-a) BARITT divedb) IMPATT divedc) Gunn divded) Step recovery diodeAnswer: c)

In the output of a normal monochrome receiver video detector voltages, which are not found, are -a) syneb) videoc) sweepd) soundAnswer: c)

The HV anode supply for the picture tube of TV receiver is generated in the-a) mains transformerb) vertical output stagec) horizontal output staged) horizontal deflection oscillatorAnswer: c)

In antenna measurements using two aperture antennas of dimensions D1 and D2 , minimum separation between the two should be (x is free space wavelength of radiation uses) The frquency range for satellite broad casting is ?Answer: (D12+D22)/xThe frquency range for satellite broad casting isa) 30 MHz - 300MHzb) 30 MHz - 3 GHzc) 3 GHz - 30 GHzd) 30 GHz - 300 GHzAnswer: c)

Iris is used to ?a) Over come power lossb) Over come bending effectc) Over come mismatch errord) Over come twist effectAnswer: c)

In schotty barrier diode current flows because of ?a) Majority carriersb) Minority carriersc) Majority and minority carriersd) NoneAnswer: b)

Which antennas are used in microwave communication ?a) long wave antennasb) Rhombic antennasc) Parabolaidal antennas

d) All of aboveAnswer: c)

Among translator & time of sight system capacity ?a) Of translator is moreb) Of line of sight is morec) Having equal capacityd) No relation such asAnswer: a)

No of T-state required for memory read or write operation-a) 2b) 3c) 4d) 6Answer: b)

In data transfer operation which flag get affected-a) 3140 flog.b) carry flogc) sign flog.d) noneAnswer: d)

While executing program microprocessor checks INTR line clearing-a) each instructionb) after interval of two instructionc) after a subroutined) at the end of program.Answer: a)

93. In which error check technique of data communication 2?s complement of all bytes of data is transmitted with data-a) Even parityb) odd parityc) check scansd) cyclic redundancyAnswer: a)

Program execution hierarchy decides which operator-a) is most importantb) is used firstc) is fastestd) operators on largest numberAnswer: c)

(375)10 = (?-)8a) 550b) 557c) 567d) 577Answer: c)

To obtain 2048 8 memory using 128 8 memory chip how many IC required-a) 2

b) 4c) 8d) 16Answer: d)

A Decimal no. 17 can be converted in binary, the binary no. will be.-a) 10001b) 01110c)00111d) 11100Answer: a)

Is the Universal logic gate-a) ANDb) ORc) NANDd) X-ORAnswer: c)

A monostable state in multivibrator means-a) which returns itself to its single stable stateb) the state used only once in circuitc) the state of circuit can not get changedd) the state of circuit always changingAnswer: a)

For designing binary counter which flip flop is preferred -a) T FFb) SR FFc) D FFd) JKFFAnswer: c)

His handwriting was not ?? so I could not read his note ?a) attractiveb) eligiblec) cleard) legibleAnswer: d)

They started to ?? people into the theatre only at six -a) enterb) admitc) followd) acceptAnswer: a)

I told him to buy things that are lasting (Give the appropriate synonym of the underlined word).a) endingb) ordinaryc) durabled) cheapAnswer: c)

Give the word which is most opposite in meaning of the word ?evident?-a) doubtful

b) unimportantc) disagreedd) understoodAnswer: a)

I expressed by disagreement ?? him on that issue-a) betweenb) withc) aboutd) forAnswer: b)

?Sugarbowl? of the world is -a) Indiab) Cubac) Brazild) USAAnswer: b)

Palk strait separates-a) India and Srilankab) India and Burmac) Britain and Franced) Malaysia and SumatraAnswer: a)

The minimum number of atoms in a molecule of an element are-a) 1b) 5c) 2d) 10

Tides in the sea are caused by-a) Effect of sunb) Effect of moonc) combined effect of moon and sund) Gravitational, centrifugal and centripetal forcesAnswer: c)

The Bar council of India decided to close over law colleges across the country for their failure to maintain minimum teaching standard) There number isa) 140b) 200c) 150d) 100Answer: c)

Aswan Dam is located in-a) Egyptb) Libyac) Sudand) IranAnswer: a)

Ghana Birds sanctuary is in the state of -a)Rajasthanb)Madhya Pradeshc)Uttar Pradesh

d)MaharashtraAnswer: a)

Dry ice is-a) Frozen carbon monoxideb) Frozen carbon dioxidec) Frozen ammoniad) None of theseAnswer: b)

East flower river of India is -a) Cauveryb) sonec) Narmadad) TaptiAnswer: a)

The total length of the great wall of China is ?a) 1,400 milesb) 1,500 milesc) 1,300 milesd) 1,400 milesAnswer: a)

Deficiency of vitamin C may result in-a) beriberib) night blindnessc) dermatitisd) ScurvyAnswer: d)

Bharat Shah a film financer was granted bail by Supreme Court after aperiod of ?a) 11 monthsb) 2 yearsc) 18 monthsd) 15 monthsAnswer: d)

Indian local time is based on-a) 800 E longitudeb) E longitudec) 1100 E longituded) 250 E longitudeAnswer: Can you Answer this?

Which one is a good preservative of food?a) Spiritb) Formaldehydec) SugarAnswer: b)

BSNL JTO Examination Solved Model Test Paper

(Part-2)

The flow rate of electrically conducting liquid without any suspended particle cannot be measured by ?a) turbine flow metersb) electromagnetic flow metersc) ultrasonic flow meters

d) thermistor based heat loss flow metersAnswer: d)

The most useful transducer for displacement sensing with excellent sensitivity, linearity and resolution is ?a) an incremental encoderb) an abosolute encoderc) LVDTd) a strain gaugeAnswer: c)

When variable reluctance type tachometer has 150 teeth on the rotor & the counter records 13,500 pulses per second then the rotational speed will be?a) 4800 rpmb) 5400 rpmc) 6000 rpmd) 7200 rpm.Answer: b)

41. On a voltage scale, zero dB m in a 600-ohm system could refer to ?a) 1.732 Vb) 1.0 Vc) 0.7746 Vd) 0.5VAnswer: b)

One of the following devices which is required in addition in order to measure pressure using LVDT is-a) strain gaugeb) pitot tubec) Bourden tubed) RotameterAnswer: c)

It is required to measure temperature in the range of 13000 C to 15000 c) The most suitable thermocouple to be used as a transducer would be ?a) chromel - constantanb) Iron - constantanc) chromel - alumeld) platinum- rhodiumAnswer: d)

In a CSI if frequency of output voltage is f Hz, then frequency of input voltage to CSI is-a) fb) 2 fc) f/2d) 3 fAnswer: b)

Identify the type of chipper in the given circuita) Type A chopperb) Type B chopperc) Type C chopper

d) Type D chopperAnswer: b)

Maximum value of charging resistance in an UJT is associated with-a) peak pointb) valley pointc) any point between peak and valleyd) after the valley pointAnswer: a)

Thyristor A has rated gate current of 2A and thyristor B a rated gate current of 100 mA-a) A is a GTO and B is a conventional SCRb) B is a GTO and A is a conventional SCRc) B may operate as a transistord) none of the aboveAnswer: a)

In a 3 phase full converter, the output voltage during overlap is equal to-a) zerob) source voltagec) source voltage minus the inductance dropd) average value of the conducting phase voltagesAnswer: d)

Mark old the correct statement for Cycloconverters-a) step-down Cycloconverter (CC) works on natural commutationb) step up CC requires no forced commutationc) load commutated CC works on line commutationd) none of the aboveAnswer: a)

In a 3 phase full converter if load current is I and ripple free, then average thyristor current is-a)b)c)d)Answer: b)1/3(I)

In the RF amplifier stage cascade (CE-CB) amplifier is used because it gives-a) Large voltage gainb) Low output impedancec) Large isolation between the input and the outputd) None of the aboveAnswer: c)

Silicon diode is less suited for low voltage rectifier operation because-a) it can withstand high temperatureb) ensures low PIV of the diodesc) ensures lower values of capacitance in the filter

d) reduces ripple contentAnswer: a)

An amplifier of class A is that in which -a) Base is biased to cut ? offb) Ic flows most of the timec) Ie flows all the timed) Vc often raises to VccAnswer: c)

A transistor is in active region when-a) IB = bICb) IC=bIBc) IC=IEd) IC=IBAnswer: a)

For coupling purposes in RF amplifier a buffer amplifier is used because it provides-a) Maximum loading and minimum mismatchb) Minimum loading and minimum mismatchc) Maximum loading and maximum mismatchd) Minimum loading and maximum mismatchAnswer: b)

A transistor has CE parameter as hie = 10kW, hre =20 x 10-4 , hse = 100, hoe = 25 ms. The hib for this transistor will be-a) 100 Wb) 99.01 Wc) 5m Wd) 101kWAnswer: b)

An FM radio receiver is tuned to a 90.6 MHz broadcast station. It will receive an image frequency of -a) 110 MHzb) 112 Hzc) 114 MHzd) 120 MHzAnswer: b)

In the given fig RL is shorted out, then VCE will become-a) OVb) VCC ? IBRBc) Equal to VCCd) None of the aboveAnswer c)

See the circuit shown and choose the correct option ?a) Only red will glowb) Only green will glowc) Both red and green will glowd) Neither red nor green will glowAnswer: a)

A dc to dc converter having an efficiency of 80% is delivering 16W to a load) If the converter is generating an output of 200V from an input

source of 20V, then the current drawn from the source will be ?a) 0.1Ab) 0.5Ac) 1.0Ad) 10.0AAnswer: c)

A transistor is operated as a non-saturated switch to eliminate ?a) storage timeb) turn ? off timec) turn ? on timed) delay timeAnswer: b)

The output Y of the circuit in the given figure is ?a) (A + B)C + DEb) AB + C(D + E)c) (A + B)C + D + Ed) (AB + C) . DEAnswer: a)

Rotors used in a two-phase ac servomotor is ?a) solid iron motorb) squirrel cage rotorc) drag cup rotord) both b and cAnswer: d)

Major advantage of TWT over a klystron lies in its ?a) higher bandwidthb) higher outputc) higher frequencyd) higher gainAnswer: d)

The op-map circuit shown in the given figure can be used for ?a) additionb) subtractionc) both addition and subtractiond) multiplicationAnswer: d)

The Boolean expression for the shaded area in the given Venn diagram is ?Answer: AB+BC+CAA lag compensator is basically a ?a) high pass filterb) band pass filterc) low pass filterd) band elimination filterAnswer: c)

Transfer function T (S) of the system in the given fig is-Answer:The overall transfer function for a unity feedback system is 4/(S2+4S+4) Mark the correct statement

regarding this system1. Position error constant kp for the system is 42. The system type one.3. The velocity error constant kv for the system is finite.Select the correct answer using the codes given below Codesa) 1,2 and 3 b) 1 and 2 c) 2 and 3 d) 1 and 3Answer: d)

If the rotor?s resistance and reactant?s are respectively R and X1 its length and diameter are L and D for two phase a) c) servomotor, then-In a PID controllers the transfer function G(s) is-Transfer function can be approximated by the system- The transfer function of an amplifier is given by The high 3 db frequency of an amplifier will be approximately-a) 5850 kHzb) 585 kHzc) 5850 Hzd) 585 HzAnswer: X/R is small but L/D is large

The output signals amplitudes for 1?s and 0?s in an ADM transmission systems are ?a) Fixed and the repetition rate is also fixedb) Fixed but the repetition rate is variablec) Variable and the repetition rate is also variabled) Variable but the repetition rate is fixedAnswer: d)

Microwave link repeaters are typically 50km apart ?a) Because of atmospheric attenuationb) Because of Output tube power limitationsc) Because of the earth?s curvatured) To ensure that the applied ac voltage is not excessiveAnswer: c)

The amplifier inserted at intervals to amplify the signal and compensate for transmission loss on the cable are called-a) line amplifierb) equalizing amplifiersc) compradorsd) repeaters.Answer: d)

Diversity reception in used to-a) increase receiver sensitivityb) improve receiver selectivityc) overcome degrading effect of fadingd) overcome degrading effect of receiver detuningAnswer: c)

BSNL JTO Exam 2007PART I

1. Modern capacitors which have high capacitance in small size use a dielectric of(A) paper (B) rubber (C) ceramic (D) Mylar2. The Maximum spectral response of the germanium and silicon is in the(A) infrared region (B) ultraviolet region (C) visible region (D) x-ray region3. For an insulating material, dielectric strength and dielectric loss should be respectively(A) high and high (B) low and high (C) high and low (D) low and low.4. In a distortion factor meter, the filter at the front end is used suppress(A) odd harmonics (B) even harmonics (C) fundamental component (D) dccomponent5. The coefficient of coupling between two air core coils depends on(A) mutual inductance between two coils only (B) self inductances of the two coilsonly (C) mutual inductance and self inductances of the two coils (D) none6. For a parallel plate capacitor which is being charged out of the following the incorrectstatement is(A) Energy stored in the capacitor does not enter it through the connecting wirethrough the space around the wires and plates of capacitor.(B) Rate at which energy flows into this volume is equal to the integration of thepoynting vector over the boundary of the volume between the plates.(C) The poynting vector points everywhere radially outward of the volume betweenplates.(D) The poynting vector points everywhere radially in to the volume between theplates.7. The presence of alkali oxides in alumino silicate ceramics is likely to result indielectric breakdown due to(A) Polarization (B) Conductivity (C) Structural homogeneties (D) Ionization8. Which of the following will serve as a donor impurity in silion(A) Boron (B) Indium (C) Germanium (D) Antimony9. Electrical contact materials used in switches, brushes and relays must possess(A) high thermal conductivity and high melting point (B) Low thermalconductivity and low melting point(C) High thermal conductivity and low melting point (D) Low thermalconductivity and high melting point.10. An SCR can only be turned off via it's(A) cathode (B) anode (C) gates (D) none11. Gold is often diffused into silicon PN junction devices to(A) increase the recombination rate (B) reduce the recombination rate(C) make silicon a direct gap semiconductor (D) make silicon semi-metal12 With n nodes and b branches a network will have

(A) (b+n) links (B) b - n +1 links (C) b -n-1 links (D) b + n + 1 links13. When a network has 10 nodes and 17 branches in all then the number of node pairvoltages would be(A) 7 (B) 9 (C) 10 (D) 4514. In any atom the potential energy of an orbiting electron is(A) always positive (B) always negative(C) sometime positive, sometime negative (D) numerically less then its kineticenergy.15. A delition MOSFET differs from a JFET in the sense that it has no(A) channel (B) gate (C) P-N junctions (D) substrate16. The advantage of a semiconductor strain gauge cover the wire round strain guage isthat (A) it is more sensitive (B) it is more linear (C) it is less temperature dependent(D) it's cost is low17. Barrier potential in a P-N junction is caused by(A) thermally generated electrons and holes (B) diffusion of majority carriersacross the junction(C) migration of minority carriers across the junction (D) flow of drift current.18. When an NPN transistor is properly biased then most of the electrons from the emitter(A) recombine with holes in the base (B) recombine in the emitter itself(C) pass through the base to the collector (D) are stopped by the junction barrier19. The deplition voltage for silicon diode at 0 bias is(A) 0.5 volt (B) 0.3 volt (C) 0.7 volt (D) 1.1 volt20. A UJT can(A) be triggered by any one of it's three terminals (B) not be triggered(C) be triggered by two of its three terminal only (D) be triggered by all of itsterminals only.21. The energy of electric field due to a spherical charge distribution of radius r andinform charge density in vacuum is22. Maxwells divergence equation for the magnetic field is given byA. ▼* B = 0 B. ▼ . B = 0__ __ __ __C. ▼* B = p D. ▼ . B = p23. When a short grounded vertical antenna has a length L which is 0.05 1 at frequency fand if it's radiation resistancesat f is R Ohms, then its radiation resistance at a frequency 2f will be(A) R/2 ohms (B) R ohms (C) 2R ohms (D) 4R ohms24.In a cylindrical cavity resonator, the two modes which are degenerate would include(A) TE111 and TM111 (B) TE011 and TM011 (C) TE022 and TM111 (D) TE111 andTM01125. When an antenna of input resistance 73 ohm is connected to a 50-ohm line and if thelosses are ignored then itsefficiency will be nearly

(A) 0.19 (B) 0.81 (C) 0.97 (D) 1.1926.The transformer utilization factor of full wave bridge rectifier is(A) 0.812 (B) 0.286 (C) 0.693 (D) 0.78227. When a dominant mode wave guide not terminated in its characteristic impedance isexcited with a 10 GHZ signalthen if d is the distance between two successive minima of the standing wave in theguide then(A) d = 1.5 cm (B) d is less then 1.5 cm (C) d is greater then 1.5 cm (D) d =3cm28. A two port network having a 6 dB loss will give(A) an output power which is one - quarter of the input power (B) an output powerwhich is one -half of the input power(C) an output voltage which is 0.707 of the input voltage. (D) an output powerwhich is 0.707of the input power.29. While transporting a sensitive galvanometer

(A) the terminals are kept shorted (B) critical damping resistance is connectedacross the terminals(C) the terminals are kept open circuited (D) it does not matter as to what isconnected across the terminals.30. A T type attenuator is designed for an attenuation of 40 dB and terminating resistanceof 75 ohms.Which of the following values represent full series arm R1 and shunt arm R2?1.R1 = 147 Ω 2. R1 = 153 Ω 3. R1 = 1.5 Ω 4. R1= 3750 Ω(A) 1 and 3 (B) 1 and 4 (C) 2 and 3 (D) 2 and 431. For a transmission line, the characteristic impedance with inductance 0.294 μH/mand capacitance 60pF/m is(A) 49 Ω (B) 60 Ω (C) 70 Ω (D) 140 Ω32. When the graph of a network has six branches with three tree branches then theminimum numberof equations required for the solution of the network is(A) 2 (B) 3 (C) 4 (D) 533. Consider the following statement for a 2-port network1. Z11 =Z22 2. h12 = h21 3.Y12 = -Y21 4.BC - AD = -1then the network is reciprocal if and only if(A) 1 and 2 are correct (B) 2 and 3 are correct (C) 3 and 4 are correct (D) 4alone is correct.34. As a network contains only independent current sources and resistors then if thevalues of allresistors are doubled then the values of the node voltages are(A) will become half (B) will remain unchanged(C) will become double (D) cannot be determined unless the circuit configurationand the valuesof the resistors are known.

35. A iron cored choke is a (A) Linear and active device (B) Non linear and passive device (C) Active deviceonly (D) Linear device only36. Poynting vector wattmeter is based on(A) Seebeck effect (B) Ferranti effect (C) Induction effect (D) Hall effect37. Which one of the following is not a transducer in the true sense?(A) Thermocouple (B) Piezoelectric pick-up (C) Photo voltaic cell (D) LCD.38. The term used to denote a static device that converts ac to dc, de to ac, dc to dc or acto ac is(A) Converter system (B) Inverter (C) Chopper (D) Thyristor39. When a dipole antenna of 1/8 length has an equivalent total resistance of 1.5 Wattthen theefficiency of the antenna is(A) 0.89159% (B) 8.9159% (C) 89.159% (D) 891.59%40. In commercial FM broadcasting, the maximum frequency deviation is normally(A) 5 KHz (B) 15 KHz (C) 75 KHz (D) 200 KHz41. Weins bridge is used for measurement of frequency in the applied voltage waveformis measurementof frequency in the applied voltage waveform is(A)sinusoidal (B) square (C) rectangular (D) triangular42.Strain gauge is(A) not a transducer (B) an active transducer (C) not an electronic instrument43.A high Q coil has(A) large band width (B) high losses (C) low losses (D) flat response44. In the case of an instrument reading of 8.3 V with a 0 to 150 voltmeter having aguaranteed accuracy of1% full scale reading, the percentage limiting error is(A) 1.810% (B) 0.181% (C)12.45% (D) 0.0018%45. The 'h' parameter equivalent circuit of a junction transistor is valid for(A) High frequency, large signal operation (B) High frequency, small signaloperation (C) Low frequency,large signal operation.46. A system is causal if the output of any time depends only on(A) Values of input in the past and in the future (B) Values of input at that timeand in the past(C) Values of input at that time and in the future (D) none

47. Form the hot metal surface electrons escape because(A) of change of state from metal to gas due to heat. (B) of change of state fromgas to metal(C) the energy supplied is greater than the work function (D) the energy is greaterthan Fermi level

48. The most common device used for detection in radio receivers is

(A)amplifier (B) triode (C) diode (D) transistor

49. In a full wave rectifier the negative point in a circuit is(A) cathode (B) anode (C) The central tap on the high voltage secondary (D)plate.50.Negative feedback amplifier has a signal corrupted by noise as its input. The amplifierwill(A) Amplify the noise as much as the signal (B) Reduce the noise (C) Increasethe noise(D) Not effect the noisePART - II51. It is an unidirectional device that blocks the current flow from cathode to anode(A) SCR (B) PCR (C) VCR (D) DCR52. An ideal constant current source is connected in series with an ideal constant voltagesource. Considering togetherthe combination will be a (A) constant voltage source (B)constant current source(C) constant voltage and a constant current source or a constant power source. (D)resistance53. Anode current in an thyristor is made up of(A) electrons only (B) electrons or holes (C) electrons and holes (D) holes only54. For a pulse transformer, the material used for its core and the possible turn rationfrom primary to secondary arerespectively(A) ferrite : 20 : 1 (B) laminated iron : 1 :1 (C) ferrite : 1 : 1 (D) powered iron :1: 155. A converter which can operate in both 3 pulse and 6 pulse mode is a(A) 1 phase full converter (B) 3 phase half wave converter (C) 3 phase semiconverter (D) 3 phase full converter.56. A single phase CSI has capacitor C as the load. For a constant source current, thevoltage across the capacitor is(A) square wave (B) triangular wave (C) step function (D) pulsed wave57. a single phase full wave midpoint thyristor converter uses a 230/200V transformerwith centre tapon the secondary side. The P.I.V per thyristor is(A) 100V (B)141.4V (C)200V (D)282.8V58. In dc choppers for chopping period T, the output voltage can be controlled by FM byvarying(A) T keeping Ton constant (B) Ton keeping T constant(C) Toff keeping T constant (D) None of the above

59.An ideal power supply consist of(A) Very small output resistance (B) Zero Internal resistance(C) Very large input resistance (D) Very large output resistance

60. The linearity error for a digital input is indicated by

(A) ξ (B) γ (C) η (D) ε

61. In the 8421 BCD code the decimal number 125 is written as(A) 1111101 (B) 0001 0010 0101 (C) 7D (D) None of the bove62. Match the given feedback circuit with its proper nomenclatures(A) Current series feedback (B) Current shunt feedback(C) Voltage series feedback (D) Voltage shunt feedback63. Class A amplifier is used when(A) No phase inversion is required (B) Highest voltage gain is required(C) dc voltages are to be amplified (D) Minimum distortion is desired.64. Identity the correct match for the given transister (A) Enhancement type P channel MOSFET (B) Depletion type N channelMOSFET(C) Enhancement type N channel MOSFET (D) Depletion type P channelMOSFET65. In case a signal band limited to fermimeter is sampled at a rate less than 2 fermimeter,the constructed signal will be(A) Distortionless (B) Small in amplitude (C) Having higher frequenciessuppressed (D) Distorted66.IC which has quad 2 input AND gates(A) 7411 (B) 7404 (C)7400 (D) 740867. Registers in which data is entered or taken out in serial form are referred as(A) left shift register (B) right shift register (C) shift registers (D) none of theabove68. The expression ABC can be simplified to__ __ __A. A B C B. AB+BC+CA__ __ __ __C. AB+ C C. A + B + C69. Read the following(i) Routh Herwitz's criterion is in time domain (ii)Root locus plot is in time domain(iii) Bode plot is in frequency domain(iv) Nyquist criterion is in frequency domain.(A) 2,3 and 4 are correct (B) 1,2 and 3 are correct (C) 3 and 4 are correct (D)all four are correct70. Register and counters are similar in the sense that they both(A) count pulses (B) store binary operation (C) shift operation(C) made from an array of flip flops and gates integrated on a single chip.71. In D/A converter, the resolution required is 50mv and the total maximum input is 10v.The number ofbits required is(A) 7 (B) 8 (C) 9 (D) 20072. On different unit impulse function results in(A) Unit parabolic function (B) Unit triplet (C) Unit doublet (D) Unit rampfunction

73. ........... watt of power is received from sun per m2 surface area of a geosynchronoussatellite(A) 100 (B) 500 (C) 2000 (D) 100074. The ripple factor in an LC filter.(A) Increases with the load current (B) Increases with the load resistance(C) Remains constant with the load current (D) Has the lowest value75. In different parts of the country identical telephone numbers are distinguished by their(A) Language digits (B) Access digits (C) Area codes (D) Central office codes76.Amplitude modulation is used for broadcasting because(A) it is move noise immune than other modulation systems(B) compared with other systems it requires less transmitting power(C) its use avoids receiver complexity (D) no other modulation system can provide the necessary bandwidth for highfidelity.77. The maximum phase shift that can be provided by a lead compensator with transferfunction.1+6SG0(S) = ______1+2S(A) 15o (B) 45o (C) 30o (D) 60o78. The correct sequence of steps required to improve system stability is(A) Insert derivative action, use negative feedback, reduce gain(B) Reduce gain, use negative feedback, insert derivative action(C) Reduce gain, insert derivative action, use negative feedback(D) Use negative feedback, reduce gain, insert derivative action,79. Identity slope change at = 10 of the magnitude v/s frequency characteristic of aunity feedback system with thefollowing open-loop transfer function.A -80 dB/dec to -60 dB/dec B 40 dB/dec to 20 dB/decC 20 dB/dec to -40 dB/dec D 40 dB/dec to -20 dB/dec80. In the feedback control system the loop transfer function is given byKG(s)H(s)= _____________S(s+2)(s2+2s+2) Number of asymptotes of its root loci is

A. 1 B. 2 C. 3 D. 481. In a closed - loop transfer functionG(s) 2600 k(s+25)____ = _____________________________H(s) s4+125s3+5100s2+65000s+65000 kA. ±j228 B. ±j2.28 C. ±j1.14 D. j11482. Considering the following statement : In a magic tee1. the collinear arms are isolated from each other2. one of the collinear is isolated from the E-arm3. one of the collinear arm is isolated from the H-arm

4. E-arm and H-arm are isolated from each other. Of these statements(A) 1 and 2 are correct (B) 1 and 3 are correct (C) 1 and 4 are correct (D) 2 and3 are correct.83. In 1965 first geostationary satellite was launched called(A) ANIK (B) EARLY BIRD (Intel sat - 1) (C) WESTAR (D)MOLNIYA84. When A = 0., B = 0, C = 1 then in two input logic gate we get gate(A) XOR gate (B) AND gate (C) NAND gate (D) NOR gate85. In a radio receiver the IF amplifier(A) is tuned above the stations incoming frequency (B) amplifies the output of localoscillator(C) is fixed tuned to one particular frequency (D) can be tuned to various isolatefrequencies86. A duplexer is used to(A) Couple two antennas to a transmitter without interference(B) isolate the antenna from the local oscillator(C) prevent interference between two antennas connected to a receiver(D) use an antenna for reception or transmission without interference.87. Boolean algebra is based on(A) numbers (B) logic (C) truth (D) symbols88. The amplifiers following the modulated stage in a low level modulation AM systembe(A) linear amplifier (B) harmonic generators (C) class C power amplifiers (D) classuntuned amplifiers89. In a radar system maximum unambiguous range depends on(A) maximum power of the transmitter (B) pulse repetition frequency(C) width of the transmitted pulse (D) sensitivity of the radar receiver.90. In composite video waveform the function of the serrations, is to(A) equalize the charge in the integrator before the start of vertical retrace(B) help vertical synchronization (D) simplify the generation of the vertical sync pulse91. The frequency range 30MHz - 300MHz is(A) medium frequency (B) very high frequency (C) super high frequency (D)Infrared frequency92. Which wave cannot exist inside wave guide(A) TE (B) TM (C) TEM (D) HE93.Ionosphere layer of earth is situated at(A) upto 18 kms from earth (B) from 18 to 70 km (C) 70 to 500 km (D) above500km94. A two cavity klystron tube is a(A) velocity modulated tube (B) frequency modulated tube(C) Amplitude modulated tube (D) simple triode95. As the thermal noise get doubled due to the increase in a resistance the noise powerget.(A) doubled (B) quadruped (C) unchanged (D) halved.

96.Which one is a cross field tube(A) Klystron (B) Reflex Klystron (C) Magnetron (D) TWT97. The degree of coupling depends(A) size of hole (B) location of holes (C) size and location of holes (D) not dependon size or location of hole98. The thermal noise depends on(A) direct current through device(B) resistive component of resistance(C) reactive component of impedance(D) load to connected.99. The charge on a hole is(A) 1.6 x 10-9 (B) 1.6 x 10-19 (C) 1.6 x 101 (D) 1.6 x 1020100. Intel's 8085 microprocessor chip contains(A) seven 8 bit registers (B) 8 seven bits registers (C) seven 7 bit registers (D) eight8 bit registers.PART III101. The words Satyameva Jayathe' have been taken from(A) Vedas (B) Bhagavad Gita (C) Mundaka Upanishada (D) Mahabharatha (E)None of these102.Which of the following countries was the first to develop a neutron bomb?(A) USA (B) USSR (C) China (D) Pakistan103. "Kathakali" dance is connected with(A) Kerala (B) Rajastan (C) Uttar pradesh (D) Tamil Nadu104. The term "Ashes" is associated with(A) Hockey (B) Cricket (C) Soccer (D) None of these.105. The Kailash Temple at Ellora is a specimen of(A) Gupta architecture (B) Rashtrakutlas architecture (C) Chalukya architecture (D)Chola architecturewww. 106. When the two Houses of Parliament differ regarding a Bill then the controversy issolved by(A) Joint sitting of the two Houses(B) President of India(C) Prime Minister of India(D) BY a special committee for the purpose107. Which of the following is not work of kalidasa?(A) Meghdood (B) Reghuvansha (C) Sariputra Prakarma (D) Ritushamhara108. Amir Khusro was the famous poet and aesthete of(A) Akbar the Grest (B) Mahmud Ghaznvi (C) Snah Jahan (D) Alauddin Khilji109. With the beginings of space travel, we entered a new(A) Era of great history (B) List (C) Book (D) Year110. An though it mourns the death of someone, need not be sad.(A) Funny poem (B) Newspaper article (C) Othodox talk (D) Elegy111. If stare is glance so gulp is(A) Sip (B) Tell (C) Salk (D) Admire112. He hardly works means(A) The work is hard (B) He is hard (C) The work is easy (D) He work very little.113. Give the opposite word for pulchritude

(A) antipathy (B) unsightliness (C) inexperience (D) languor114. Nanometre is ....................... part of metre(A) MIllionth (B) Ten Millionth (C) Billionth (D) Ten billionth115. Malaria affects(A) Liver (B) Spleen (C) Intestine (D) Lungs116. Sindhu Rakshak is a /an.(A) Best film director(B) Best musician(C) Best documentary(D) Best work relating to promotion of Indian film industry118. Who developed the branch of mathematics known as Calculus?(A) Arybhatta (B) Newton (C) Einstein (D) Archimedes119. In which state in Kanha Part situated?(A) M.P (B) U.P (C) Assam (D) W.Bengal120. Which day is observed as Human Rights Day?(A) 24th October (B) 4th July (C) 8th Auguest (D) 10th DecemberANSWERS1. (C) 2. (B) 3. (C) 4. (C) 5. (C) 6. (C) 7. (B) 8.(D) 9. (A) 10. (B)11. (B) 12.(B) 13. (B) 14. (B) 15. (C) 16.(A) 17. (C) 18. (C) 19. (C)20. (C) 21. (C) 22. (B) 23. (D) 24. (D) 25.(B) 26.(B) 27.(A) 28.(A)29. (B) 30.(A) 31. (C) 32. (B) 33.(D) 34. (C) 35. (B) 36. (C) 37. (D)38. (A) 39(C) 40.(C) 41. (A) 42. (B) 43.(C) 44. (C) 45.(C) 46.(B)47. (C) 48. (C) 49. (C) 50. (B) 51. (A) 52. (B) 53. (C) 54. (C) 55. (C)56. (B) 57. (D) 58. (A) 59. (B) 60. (D) 61.(A) 62. (A) 63. (D) 64. (B)65. (D) 66. (D) 67. (C) 68. (D) 69 (D) 70. (D) 71. (B) 72. (C) 73. (D)74 (D) 75. (C) 76. (C) 77.(C) 78. (D) 79. (A) 80. (D) 81. (A) 82. (C)83. (C) 84. (C) 85. (C) 86. (C) 87. (B) 88. (C) 89.(B) 90. (C) 91.(B)92. (C) 93. (C) 94. (A) 95. (C) 96. (C) 97. (B) 98. (B) 99. (B) 100. (A)101. (A) 102. (A) 103. (A) 104. (B) 105. (D) 106. (C) 107. (D) 108. (A)109. (A) 110. (D) 111. (A) 112. (D) 113. (B) 114. (B) 115. (B) 116. (D)117. (C) 118. (C) 119. (B) 120. (A).

Paper : JTO 2005 EXAM SOLVED PAPER OF YEAR 2005 (BSNL)

When a piece of copper and another of germanium are cooled from room temperature to 800 K then the resistance of -a) Each of them increasesb) Each of them decreasesc) Copper increases and germanium decreasesd) Copper decreases and germanium increasesAnswer: d)

When a signal of 10 mV at 75 MHz is to be measured then which of the following instrument can be used -a) VTVMb) Cathode ray oscilloscopec) Moving iron voltmeterd) Digital multimeterAnswer: b)

When a sample of germanium and silicon having same impurity density are kept at room temperature then ?a) Both will have equal value of resistivityb) Both will have equal value negative resistivityc) Resistivity of germanium will be higher than that of silicond) Resistivity of silicon will be higher than that of germaniumAnswer: d)

When an RC driving point impedance function has zeros at s= -2 and s=-5 then the admissible poles for the function would be ?a) s = 0; s = -6b) s = 0; s = -3c) s = 0; s = -1d) s = -3; s = -4Answer: b)

For the n-type semiconductor with n = Np and p = , the hole concentration will fall below the intrinsic value because some of the holes ?a) drop back to acceptor impurity statesb) drop to donor impurity statesc) Virtually leave the crystald) recombine with the electronsAnswer: d)

The location of lighting arrestor is ?a) Near the transformerb) Near the circuit breakerc) Away from the transformerd) NoneTime constant of an RC circuit increases if the value of the resistance is ?a) Increasedb) Decreasedc) Neither a nor bd) Both a and bAnswer: a)

Telemetering is a method of ?a) Counting pulses sent over long distancesb) Transmitting pictures from one place to anotherc) Transmitting information concerning a process over a distanced) NoneAnswer: c)

When the gauge factor of a strain gauge is 2, stress is 1050 kg/cm2, Y = 2.1? 106 kg/cm2 and R is 100 ohms then the value of DR will be -a) 2Wb) 3Wc) 4Wd) 1WAnswer: d)

As the drain voltage is increased for a junction FET in the pinch off region then the drain current ?a) Becomes zerob) Abruptly decreasesc) Abruptly increasesd) Remains constantAnswer: d)

11. One of the following, which is not a transducer in the true sense, is ?a) Thermocoupleb) Piezoelectric pick upc) Photo-Voltaic celld) LCDAnswer: d)

When a transistor is required to match a 100W signal source with a high impedance output circuit then the connection that would be used is ?

a) Common baseb) Common collectorc) Common emitterd) Emitter followerAnswer: a)

In a JFET gates are always ?a) forward biasedb) reverse biasedc) unbiasedd) noneAnswer: c)

The main factor which differentiate a DE MOSFET from an E only MOSFET is the absence of ?a) insulated gateb) electronsc) channeld) P-N junctionAn SCR conducts appreciable current when ?a) Anode and gate are both negative with respect to cathodeb) Anode and gate are both positive with respect to cathodec) Anode is negative and gate is positive with respect to cathode

d) Gate is negative and anode is positive with respect to cathodeSilicon is not suitable for fabrication of light emitting diodes because it is -a) An indirect band gap semiconductorb) A direct band gap semiconductorc) A wide band gap semiconductord) A narrow band gap semiconductorAn average responding rectifier type electronic ac voltmeter has its scale calibrated in terms of the rms value of a sine wave, when a square wave voltage of peak magnitude 100V is measured using this voltmeter then the reading indicated by the meter, will be ?a) 111Vb) 100Vc) 90.09Vd) 70.7VAnswer: b)

When a four terminal T network is inserted between a source and load resistance as shown in figure then the resistance seen by the source remain the same with or without the four terminal block when R is ?

a) 5Wb) 10 Wc) 15 Wd) 20 WAnswer: a)In the ac bridge shown in the given figure, the value of Rx and Cx at balance will be

Answer:

Which one of the following conditions for Z parameters would hold for a two port network containing linear bilateral passive circuit elements ?a) Z11 = Z22b) Z12Z21 = Z11Z22c) Z11Z12 = Z22Z21d) Z12 = Z21Answer: d)

While calculating Rth, constant current sources in the circuit are ?a) replaced by opensb) replaced by ?shorts?c) treated in parallel with other voltage sourcesd) converted into equivalent voltage sourcesAnswer: a)

Maxwell?s loop current method of solving electrical networks ?a) uses branch currentsb) utilizes kirchhoff?s voltage lawc) is confined to single-loop circuits

d) is a network reduction methodAnswer: b)

A transmission line of characteristic impedance Z0 = 50 ohms, phase velocity Vp = 2 x 108 m/s and length l = 1m is terminated by a load ZL= ( 30 ? j 40 ) ohms. The input impedance of the line for a frequency of 100 MHz will bea)(30 + j40 ) ohmsb)( 30 ? j40 ) ohmsc)(50 + j40 ) ohmsd)(50 ? j40 ) ohmsAnswer: b)

For an elliptically polarized wave incident on the interface of a dielectric at the Brewster angle then the reflected wave will be-a) Elliptically polarizedb) Linearly polarizedc) Right circularly polarizedd) Left circularly polarizedAnswer: b)

A yagi antenna has a driven antenna-a) Onlyb) With a reflectorc) With one or more directorsd) With a reflector and one or more directorsAnswer: d)

The number of lobes on each side of a 3l resonant antenna is ?a) 3b) 6c) 2d) 1Answer: b)

The electric field intensity of a Hertizian dipole at a remote point varies as -Radiation resistance of a half wave folded dipole is -a) 72 Wb) 144Wc) 288 Wd) 216WAnswer: 1/r

When a carrier wave is modulated at 100% it?s power is increased by -a)100%b)150 %c)50%d)0%Answer: c)

On a clear sky day, the atmospheric radio noise is strongest -a) During morning hours

b) Around mid-dayc) During nightsd) In the afternoonAnswer: c)

TV broadcasting system in India is as per CCIR -a) System Bb) System Ic) System Md) System XAnswer: b)

For the safety measurement of the internal resistance of a 25-0-25 mA meter, a laboratory multimeter whose sensitivity is equal to ?a) 1k ohm/volt can be usedb) 10 k ohm/volt can be usedc) 100 k ohm/volt can be usedd) 200 k ohm/volt can be usedAnswer: d)

In order to measure moisture in wood the most suitable method is ?a) Electrical conductionb) Electrical ? capacitivec) Absorption of radiationd) Equilirium- moisture vs humidityAnswer: a)

The flow rate of electrically conducting liquid without any suspended particle cannot be measured by ?a) turbine flow metersb) electromagnetic flow metersc) ultrasonic flow metersd) thermistor based heat loss flow metersAnswer: d)

The most useful transducer for displacement sensing with excellent sensitivity, linearity and resolution is ?a) an incremental encoderb) an abosolute encoderc) LVDTd) a strain gaugeAnswer: c)

When variable reluctance type tachometer has 150 teeth on the rotor & the counter records 13,500 pulses per second then the rotational speed will be?a) 4800 rpmb) 5400 rpmc) 6000 rpmd) 7200 rpm.Answer: b)

41. On a voltage scale, zero dB m in a 600-ohm system could refer to ?a) 1.732 V

b) 1.0 Vc) 0.7746 Vd) 0.5VAnswer: b)

One of the following devices which is required in addition in order to measure pressure using LVDT is-a) strain gaugeb) pitot tubec) Bourden tubed) RotameterAnswer: c)

It is required to measure temperature in the range of 13000 C to 15000 c) The most suitable thermocouple to be used as a transducer would be ?a) chromel - constantanb) Iron - constantanc) chromel - alumeld) platinum- rhodiumAnswer: d)

In a CSI if frequency of output voltage is f Hz, then frequency of input voltage to CSI is-a) fb) 2 fc) f/2d) 3 fAnswer: b)

Identify the type of chipper in the given circuit

a) Type A chopperb) Type B chopperc) Type C chopperd) Type D chopperAnswer: b)

Maximum value of charging resistance in an UJT is associated with-a) peak pointb) valley pointc) any point between peak and valleyd) after the valley pointAnswer: a)

Thyristor A has rated gate current of 2A and thyristor B a rated gate current of 100 mA-a) A is a GTO and B is a conventional SCRb) B is a GTO and A is a conventional SCRc) B may operate as a transistor

d) none of the aboveAnswer: a)

In a 3 phase full converter, the output voltage during overlap is equal to-a) zerob) source voltagec) source voltage minus the inductance dropd) average value of the conducting phase voltagesAnswer: d)

Mark old the correct statement for Cycloconverters-a) step-down Cycloconverter (CC) works on natural commutationb) step up CC requires no forced commutationc) load commutated CC works on line commutationd) none of the aboveAnswer: a)

In a 3 phase full converter if load current is I and ripple free, then average thyristor current is-a)b)c)d)Answer: b)1/3(I)

In the RF amplifier stage cascade (CE-CB) amplifier is used because it gives-a) Large voltage gainb) Low output impedancec) Large isolation between the input and the outputd) None of the aboveAnswer: c)

Silicon diode is less suited for low voltage rectifier operation because-a) it can withstand high temperatureb) ensures low PIV of the diodesc) ensures lower values of capacitance in the filterd) reduces ripple contentAnswer: a)

An amplifier of class A is that in which -a) Base is biased to cut ? offb) Ic flows most of the timec) Ie flows all the timed) Vc often raises to VccAnswer: c)

A transistor is in active region when-a) IB = bIC

b) IC=bIBc) IC=IEd) IC=IBAnswer: a)

For coupling purposes in RF amplifier a buffer amplifier is used because it provides-a) Maximum loading and minimum mismatchb) Minimum loading and minimum mismatchc) Maximum loading and maximum mismatchd) Minimum loading and maximum mismatchAnswer: b)

A transistor has CE parameter as hie = 10kW, hre =20 x 10-4 , hse = 100, hoe = 25 ms. The hib for this transistor will be-a) 100 Wb) 99.01 Wc) 5m Wd) 101kWAnswer: b)

An FM radio receiver is tuned to a 90.6 MHz broadcast station. It will receive an image frequency of -a) 110 MHzb) 112 Hzc) 114 MHzd) 120 MHzAnswer: b)

In the given fig RL is shorted out, then VCE will become-

a) OVb) VCC ? IBRBc) Equal to VCCd) None of the aboveAnswer c)

See the circuit shown and choose the correct option ?

a) Only red will glowb) Only green will glowc) Both red and green will glowd) Neither red nor green will glowAnswer: a)

A dc to dc converter having an efficiency of 80% is delivering 16W to a load) If the converter is generating an output of 200V from an input source of 20V, then the current drawn from the source will be ?a) 0.1Ab) 0.5A

c) 1.0Ad) 10.0AAnswer: c)

A transistor is operated as a non-saturated switch to eliminate ?a) storage timeb) turn ? off timec) turn ? on timed) delay timeAnswer: b)

The output Y of the circuit in the given figure is ?

a) (A + B)C + DEb) AB + C(D + E)c) (A + B)C + D + Ed) (AB + C) . DEAnswer: a)

Rotors used in a two-phase ac servomotor is ?a) solid iron motorb) squirrel cage rotorc) drag cup rotord) both b and cAnswer: d)

Major advantage of TWT over a klystron lies in its ?a) higher bandwidthb) higher outputc) higher frequencyd) higher gainAnswer: d)

The op-map circuit shown in the given figure can be used for ?

a) additionb) subtractionc) both addition and subtractiond) multiplicationAnswer: d)

The Boolean expression for the shaded area in the given Venn diagram is ?

Answer: AB+BC+CAA lag compensator is basically a ?a) high pass filterb) band pass filterc) low pass filterd) band elimination filterAnswer: c)

Transfer function T (S) of the system in the given fig is-

Answer:

The overall transfer function for a unity feedback system is 4/(S2+4S+4) Mark the correct statement regarding this system1. Position error constant kp for the system is 42. The system type one.3. The velocity error constant kv for the system is finite.Select the correct answer using the codes given below Codesa) 1,2 and 3 b) 1 and 2 c) 2 and 3 d) 1 and 3Answer: d)

If the rotor?s resistance and reactant?s are respectively R and X1 its length and diameter are L and D for two phase a) c) servomotor, then-In a PID controllers the transfer function G(s) is-Transfer function can be approximated by the system- The transfer function of an amplifier is given by The high 3 db frequency of an amplifier will be approximately-a) 5850 kHzb) 585 kHzc) 5850 Hzd) 585 HzAnswer: X/R is small but L/D is large

The output signals amplitudes for 1?s and 0?s in an ADM transmission systems are ?

a) Fixed and the repetition rate is also fixedb) Fixed but the repetition rate is variablec) Variable and the repetition rate is also variabled) Variable but the repetition rate is fixedAnswer: d)

Microwave link repeaters are typically 50km apart ?a) Because of atmospheric attenuationb) Because of Output tube power limitationsc) Because of the earth?s curvatured) To ensure that the applied ac voltage is not excessiveAnswer: c)

The amplifier inserted at intervals to amplify the signal and compensate for transmission loss on the cable are called-a) line amplifierb) equalizing amplifiersc) compradorsd) repeaters.Answer: d)

Diversity reception in used to-a) increase receiver sensitivityb) improve receiver selectivityc) overcome degrading effect of fading

d) overcome degrading effect of receiver detuningAnswer: c)

Mark out transferred electron device in the following-a) BARITT divedb) IMPATT divedc) Gunn divded) Step recovery diodeAnswer: c)

In the output of a normal monochrome receiver video detector voltages, which are not found, are -a) syneb) videoc) sweepd) soundAnswer: c)

The HV anode supply for the picture tube of TV receiver is generated in the-a) mains transformerb) vertical output stagec) horizontal output staged) horizontal deflection oscillatorAnswer: c)

In antenna measurements using two aperture antennas of dimensions D1 and D2 , minimum separation between the two should be (x is free space wavelength of radiation uses) The frquency range for satellite broad casting is ?Answer: (D12+D22)/x

The frquency range for satellite broad casting isa) 30 MHz - 300MHzb) 30 MHz - 3 GHzc) 3 GHz - 30 GHzd) 30 GHz - 300 GHzAnswer: c)

Iris is used to ?a) Over come power lossb) Over come bending effectc) Over come mismatch errord) Over come twist effectAnswer: c)

In schotty barrier diode current flows because of ?a) Majority carriersb) Minority carriersc) Majority and minority carriersd) NoneAnswer: b)

Which antennas are used in microwave communication ?a) long wave antennasb) Rhombic antennasc) Parabolaidal antennasd) All of aboveAnswer: c)

Among translator & time of sight system capacity ?a) Of translator is moreb) Of line of sight is morec) Having equal capacityd) No relation such asAnswer: a)

No of T-state required for memory read or write operation-a) 2b) 3c) 4d) 6Answer: b)

In data transfer operation which flag get affected-a) 3140 flog.b) carry flogc) sign flog.d) noneAnswer: d)

The storage and retrieval of data on stacks should follow sequence-a) last in first outb) first in first outc) random in random outd) noneIn flowchart which figure represents process like subroutine-| | | |While executing program microprocessor checks INTR line clearing-a) each instructionb) after interval of two instructionc) after a subroutined) at the end of program.Answer: a)

93. In which error check technique of data communication 2?s complement of all bytes of data is transmitted with data-a) Even parityb) odd parityc) check scansd) cyclic redundancyAnswer: a)

Program execution hierarchy decides which operator-a) is most importantb) is used firstc) is fastestd) operators on largest numberAnswer: c)

(375)10 = (?-)8a) 550b) 557c) 567d) 577Answer: c)

To obtain 2048 8 memory using 128 8 memory chip how many IC required-a) 2b) 4c) 8d) 16Answer: d)

A Decimal no. 17 can be converted in binary, the binary no. will be.-a) 10001b) 01110c)00111d) 11100Answer: a)

Is the Universal logic gate-a) ANDb) ORc) NANDd) X-ORAnswer: c)

A monostable state in multivibrator means-a) which returns itself to its single stable stateb) the state used only once in circuitc) the state of circuit can not get changedd) the state of circuit always changingAnswer: a)

For designing binary counter which flip flop is preferred -a) T FFb) SR FFc) D FFd) JKFFAnswer: c)

His handwriting was not ?? so I could not read his note ?a) attractive

b) eligiblec) cleard) legibleAnswer: d)

They started to ?? people into the theatre only at six -a) enterb) admitc) followd) acceptAnswer: a)

I told him to buy things that are lasting (Give the appropriate synonym of the underlined word).a) endingb) ordinaryc) durabled) cheapAnswer: c)

Give the word which is most opposite in meaning of the word ?evident?-a) doubtfulb) unimportantc) disagreedd) understoodAnswer: a)

I expressed by disagreement ?? him on that issue-a) betweenb) withc) aboutd) forAnswer: b)

?Sugarbowl? of the world is -a) Indiab) Cubac) Brazild) USAAnswer: b)

Palk strait separates-a) India and Srilankab) India and Burmac) Britain and Franced) Malaysia and SumatraAnswer: a)

The minimum number of atoms in a molecule of an element are-a) 1b) 5c) 2d) 10

Tides in the sea are caused by-a) Effect of sunb) Effect of moonc) combined effect of moon and sund) Gravitational, centrifugal and centripetal forcesAnswer: c)

The Bar council of India decided to close over law colleges across the country for their failure to maintain minimum teaching standard) There number isa) 140b) 200c) 150d) 100Answer: c)

Aswan Dam is located in-a) Egyptb) Libyac) Sudand) IranAnswer: a)

Ghana Birds sanctuary is in the state of -a)Rajasthanb)Madhya Pradeshc)Uttar Pradeshd)MaharashtraAnswer: a)

Dry ice is-a) Frozen carbon monoxideb) Frozen carbon dioxidec) Frozen ammoniad) None of theseAnswer: b)

East flower river of India is -a) Cauveryb) sonec) Narmadad) TaptiAnswer: a)

The total length of the great wall of China is ?a) 1,400 milesb) 1,500 milesc) 1,300 milesd) 1,400 milesAnswer: a)

Deficiency of vitamin C may result in-a) beriberib) night blindnessc) dermatitisd) ScurvyAnswer: d)

Bharat Shah a film financer was granted bail by Supreme Court after a

period of ?a) 11 monthsb) 2 yearsc) 18 monthsd) 15 monthsAnswer: d)

Indian local time is based on-a) 800 E longitudeb) E longitudec) 1100 E longituded) 250 E longitudeAnswer: Can you Answer this?

Which one is a good preservative of food?a) Spiritb) Formaldehydec) SugarAnswer: b)

RRB JUNIOR ENGINEERS PRACTICE QUESTIONSRailway Engineering Exam Solved Questions:

1. The limiting value of super elevation of board gauge in Indian Railways is:(a) 16.50 cm (b) 30 cm (c) 15 cm (d) 10 cmAns : A2. Which of the following is not a part of rail engine?(a) Tender (b) Stream turbine (c) Boiler (d) Fire boxAns : B3. The staggered rails joints are usually provided on:(a) Bridge (b) Curves (c) Branching (d) TangentsAns : B4. In broad gauge, the clear horizontal distance between the inner faces of two parallel rails forming the track is:(a) 1 m (b) 1.676 m (c) 0.6096 m (d) 0.792 mAns : B5. Generally the shape of fish plate is:(a) elliptical (b) bone shaped (c) circular (d) rectangularAns : B6. The track capacity can be increased by:(a) Faster movement of trains on the track(b) By using more powerful engines(c) All the above(d) None of the aboveAns : C7. Detonating signals are used:(a) for noisy engines(b) during foggy and cloudy weather(c) for deaf drivers(d) not now, were in use in nineteenth century onlyAns : B8. Wider gauge permits:(a) sleeper gradients (b) low axle load(c) higher operating speeds (d) sharp curvesAns : C

9. The railway station at which a track line meets a main line is called:(a) terminal station (b) flag station(c) way side station (d) junction stationAns : D10. Points and crossings are provided for change of ….on permanent ways.(a) gauge (b) direction and gradient(c) direction (d) gradientAns : C11. The chart used for recording the condition of track is known as:(a) Rolling chart (b) Track chart(c) Hallade chart (d) Vibro chartAns: C12. The most common system of signaling in India is the …… system.(a) automatic block (b) section clear system(c) absolute block (d) pilot guard systemAns : C13. The feeder gauge …. is commonly used for feeding raw materials to big Government manufacturing concerns aswell as to private factories such as steel plants, oil refineries, sugar factories etc.(a) 0.6096 m (b) 0.792 m (c) 1m (d) 1.676 mAns : A14. A parabolic curve introduced between straight and a circular curve or between two branches of a compound curvefor ease, comfort and safety of movement of trains on curve is called:(a) Spur curve (b) Transition curve(c) Summit curve (d) Valley curveAns : B15. The railway track from which a train is to be diverted is called:(a) branch track (b) points and crossing(c) main or through track (d) all aboveAns : C16. An expansion gap of …. is usually kept between the adjoining rail ends to allow for expansion of rail, due tovariation in temperature.(a) 1 to 3 mm (b) 10 to 15 mm(c) 6 to 8 mm (d) 3 to 5 mmAns : C17. Which one of the following bolts is not used in rail track:(a) Fang bolt (b) Eye bolt (c) Rag bolt (d) Fish boltAns : B18. The gradient which requires one or more additional locomotive for hauling the load over the gradient is called:(a) Up-gradient (b) Pusher gradient(c) Steep gradient (d) Momentum gradientAns : B19. In locomotive ‘hunting’ is:(a) Movement of locomotive in vertical plane perpendicular to its movement along the track(b) Sinuous path taken by engine as against the alignment of the track(c) Motion after brakes have been applied(d) Combination of A and B aboveAns : D20. The rails which get battered due to action of wheels over the end of the rails are called:

(a) Hogged rails (b) Roaring rails(c) Creep rails (d) Bucking railsAns : A21. As per Indian standard, the recommended width of ballast section at foot level of rails for broad gauge tracksshould be:(a) 4.38 m (b) 3.35 m (c) 1.83 m (d) 2.25 mAns : B22. The minimum length of a passenger platform for broad gauge railway should not be less than:(a) 305 m (b) 183 m (c) 495 m (d) 250 Ans : A23. For wooden sleepers, size of the ballast should be:(a) 2.54 cm (b) 10.16 cm (c) 3.8 cm (d) 5.1 cmAns : C24. The length of track under the control of a Ganger is:(a) 10 to 15 Km (b) 5 to 6 KM(c) 3 to 5 KM (d) 1 to 2 KMAns : B5. The maximum rising gradient which is provided keeping the power of locomotive in view, is called(a) Momentum gradient (b) Pusher gradient(c) Down gradient (d) Ruling gradientAns : D26. The latest system of signaling introduced is:(a) C.T.C. system (b) pilot guard system(c) section clear system (d) automatic block systemAns : A27. The maximum gradient for broad gauge in station yards in Indian Railways is:(a) 1 in 100 (b) 1 in 1000 (c) 1in 200 (d) 1 in 400Ans : D28. The force which resists the forward movement and speed of train is called:(a) Track modulus (b) Hauling resistance(c) friction (d) Tractive resistanceAns : D29. The number of fish bolts used for joining the rails with the help of fish plates, is generally:(a) 4 (b) 8 (c) 2 (d) 6Ans : A30. The Railways provided underground at a depth of about 18 m or more are called:(a) Mono railway (b) Underground railway(c) Railway (d) Tube railwayAns : D31. The creep in rails is measured in:(a) cm/kg (b) cm (c) Kg/cm (d) kg cmAns : B32. The art of providing an outward slope of …. to the treads of wheels of rolling stock is known as coning of wheels.(a) 1 in 30 (b) 1 in 10 (c) 1 in 4 (d) 1 in 20Ans : D33. The process of connecting a track length by an electric circuit is known as track circuiting and the sleepers whichare suitable for it are: (a) cast iron sleepers (b) steel sleepers(c) wooden sleepers (d) all above are suitableAns : C

34. The yard where trains and other loads are received, sorted out, trains formed and dispatched onwards are knownas:(a) locomotive yard (b) goods yard(c) marshalling yard (d) station yardAns : C35. Which one of the following is expected to have shorter life?(a) Steam engine (b) Diesel engine(c) Electric engine (d) Shunting engineAnd : B36. The movable end of the tapered rail, by means of which the flanged wheels of the train are diverted from one trackto another is known as:(a) Toe (b) Stud (c) Heel (d) FlareAns : A37. When a rail loses its weight by 5%, it should be renewed and the old one can be used on unimportant tracks, butthe rails which have lost their weight by more than …., should not be used on any track under any circumstances.(a) 8% (b) 33.3% (c) 10% (d) 20%Ans : C38. A dynamometer car is used for:(a) Tourists (b) Dinning facilities(c) Inspection of administrative officers(d) Recording the condition of trackAns : D39. When a railway line crosses a valley, a ridge like structure consisting of a series of piers, piles or trestles on whichsteel girders are placed and which is constructed usually for small spans is known as:(a) Bridge (b) Tunnel (c) Viaduct (d) AqueductAns : C40. The movable tapered end of the tongue rail is known as:(a) heel of switch (b) toe of switch(c) stretcher bar (d) throw of switchAns : B41. In railways, super elevation is provided to:(a) facilitate drainage(b) counteract the centrifugal push(c) counteract the centripetal pull(d) have all the effects mentioned aboveAns : B42. The rails which help in channelising the wheels in their proper routes are known as:(a) Guard rails (b) Wing rails? (c) Check rails (d) Lead railsAns : B43. The shape of wheels of rolling stock is:(a) Tapered with flange on outside (b) Parallel with flange on inside(c) Tapered with flange on inside(d) Parallel with flange on outsideAns : C44. The tractive resistance of the route in railways as compared to roadways will be:(a) same (b) more (c) low (d) not comparableAns : C45. Sand is used as ballast incase of:(a) steel sleepers(b) wooden sleepers

(c) reinforced concrete sleepers(d) cast iron sleepersAns : D46. Arm type fixed signals, fitted on a vertical post fixed at the side of a track, are called:(a) Warner signals (b) Starter signals(c) Semaphore signals (d) Cab signalsAns : C47. The Railway provided just below the ground level are called:(a) Tube railway (b) Underground railway(c) Mono railway (d) RailwayAns : B48. Creeping of rails will be reduced by using:(a) Bearing plates (b) Spikes (c) Chairs (d) AnchorsAns : D49. Generally the weight/metre of the rails used in broad gauge is:(a) 55 kg (b) 45 kg (c) 35 kg (d) 65 kgAns : A50. The additional track connected to main line at both of its ends is called:(a) running line (b) loop line(c) main line (d) none are correctAns : B

RRB Engineering Solved Question Papers

1. A parabolic curve introduced between straight and a circular curve or between two branches of a compound curvefor ease, comfort and safety of movement of trains on curve is called:(a) Spur curve (b) Transition curve(c) Summit curve (d) Valley curveAns : B2. The staggered rails joints are usually provided on:(a) Bridge (b) Curves (c) Branching (d) TangentsAns : B3. The track capacity can be increased by:(a) Faster movement of trains on the track(b) By using more powerful engines(c) All the above(d) None of the aboveAns : C4. The railway station at which a track line meets a main line is called:(a) terminal station (b) flag station(c) way side station (d) junction stationAns : D5. The limiting value of super elevation of board gauge in Indian Railways is:(a) 16.50 cm (b) 30 cm (c) 15 cm (d) 10 cmAns : A6. The chart used for recording the condition of track is known as:(a) Rolling chart (b) Track chart(c) Hallade chart (d) Vibro chartAns: C7. The most common system of signaling in India is the …… system.

(a) automatic block (b) section clear system(c) absolute block (d) pilot guard systemAns : C8. The feeder gauge …. is commonly used for feeding raw materials to big Government manufacturing concerns aswell as to private factories such as steel plants, oil refineries, sugar factories etc.(a) 0.6096 m (b) 0.792 m (c) 1m (d) 1.676 mAns : A9. Which one of the following bolts is not used in rail track:(a) Fang bolt (b) Eye bolt (c) Rag bolt (d) Fish boltAns : B10. The gradient which requires one or more additional locomotive for hauling the load over the gradient is called:(a) Up-gradient (b) Pusher gradient(c) Steep gradient (d) Momentum gradientAns : B11. Points and crossings are provided for change of ….on permanent ways.(a) gauge (b) direction and gradient(c) direction (d) gradientAns : C12. In locomotive ‘hunting’ is:(a) Movement of locomotive in vertical plane perpendicular to its movement along the track(b) Sinuous path taken by engine as against the alignment of the track(c) Motion after brakes have been applied(d) Combination of A and B aboveAns : D13. The rails which get battered due to action of wheels over the end of the rails are called:(a) Hogged rails (b) Roaring rails(c) Creep rails (d) Bucking railsAns : A14. In broad gauge, the clear horizontal distance between the inner faces of two parallel rails forming the track is:(a) 1 m (b) 1.676 m (c) 0.6096 m (d) 0.792 mAns : B15. As per Indian standard, the recommended width of ballast section at foot level of rails for broad gauge tracksshould be:(a) 4.38 m (b) 3.35 m (c) 1.83 m (d) 2.25 mAns : B16. The minimum length of a passenger platform for broad gauge railway should not be less than:(a) 305 m (b) 183 m (c) 495 m (d) 250 mAns : A17. Generally the shape of fish plate is:(a) elliptical (b) bone shaped (c) circular (d) rectangularAns : B18. For wooden sleepers, size of the ballast should be:(a) 2.54 cm (b) 10.16 cm (c) 3.8 cm (d) 5.1 cmAns : C69. The length of track under the control of a Ganger is:(a) 10 to 15 Km (b) 5 to 6 KM(c) 3 to 5 KM (d) 1 to 2 KMAns : B

20. The maximum rising gradient which is provided keeping the power of locomotive in view, is called(a) Momentum gradient (b) Pusher gradient(c) Down gradient (d) Ruling gradientAns : D21. The latest system of signaling introduced is:(a) C.T.C. system (b) pilot guard system(c) section clear system (d) automatic block systemAns : A22. Detonating signals are used:(a) for noisy engines(b) during foggy and cloudy weather(c) for deaf drivers(d) not now, were in use in nineteenth century onlyAns : B23. The number of fish bolts used for joining the rails with the help of fish plates, is generally:(a) 4 (b) 8 (c) 2 (d) 6Ans : A24. The Railways provided underground at a depth of about 18 m or more are called:(a) Mono railway (b) Underground railway(c) Railway (d) Tube railwayAns : D25. The art of providing an outward slope of …. to the treads of wheels of rolling stock is known as coning of wheels.(a) 1 in 30 (b) 1 in 10 (c) 1 in 4 (d) 1 in 20Ans : D26. The process of connecting a track length by an electric circuit is known as track circuiting and the sleepers whichare suitable for it are:(a) cast iron sleepers (b) steel sleepers(c) wooden sleepers (d) all above are suitableAns : C27. The movable tapered end of the tongue rail is known as:(a) heel of switch (b) toe of switch(c) stretcher bar (d) throw of switchAns : B28. The yard where trains and other loads are received, sorted out, trains formed and dispatched onwards are knownas:(a) locomotive yard (b) goods yard(c) marshalling yard (d) station yardAns : C29. Wider gauge permits:(a) sleeper gradients (b) low axle load(c) higher operating speeds (d) sharp curvesAns : C30. Which one of the following is expected to have shorter life?(a) Steam engine (b) Diesel engine(c) Electric engine (d) Shunting engineAnd : B31. The movable end of the tapered rail, by means of which the flanged wheels of the train are diverted from one trackto another is known as:(a) Toe (b) Stud (c) Heel (d) FlareAns : A32. The creep in rails is measured in:

(a) cm/kg (b) cm (c) Kg/cm (d) kg cmAns : B33. When a rail loses its weight by 5%, it should be renewed and the old one can be used on unimportant tracks, butthe rails which have lost their weight by more than …., should not be used on any track under any circumstances.(a) 8% (b) 33.3% (c) 10% (d) 20%Ans : C34. In railways, super elevation is provided to:(a) facilitate drainage (b) counteract the centrifugal push(c) counteract the centripetal pull(d) have all the effects mentioned aboveAns : B35. The additional track connected to main line at both of its ends is called:(a) running line (b) loop line(c) main line (d) none are correctAns : B36. The rails which help in channelising the wheels in their proper routes are known as:(a) Guard rails (b) Wing rails? (c) Check rails (d) Lead railsAns : B37. The shape of wheels of rolling stock is:(a) Tapered with flange on outside(b) Parallel with flange on inside(c) Tapered with flange on inside(d) Parallel with flange on outsideAns : C38. The maximum gradient for broad gauge in station yards in Indian Railways is:(a) 1 in 100 (b) 1 in 1000 (c) 1in 200 (d) 1 in 400Ans : D39. The force which resists the forward movement and speed of train is called:(a) Track modulus (b) Hauling resistance(c) friction (d) Tractive resistanceAns : D4. The tractive resistance of the route in railways as compared to roadways will be:(a) same (b) more (c) low (d) not comparableAns : C41. Sand is used as ballast incase of:(a) steel sleepers(b) wooden sleepers(c) reinforced concrete sleepers(d) cast iron sleepersAns : D42. Arm type fixed signals, fitted on a vertical post fixed at the side of a track, are called:(a) Warner signals (b) Starter signals(c) Semaphore signals (d) Cab signalsAns : C43. The Railway provided just below the ground level are called:(a) Tube railway (b) Underground railway(c) Mono railway (d) RailwayAns : B44. When a railway line crosses a valley, a ridge like structure consisting of a series of piers, piles or trestles on whichsteel girders are placed and which is constructed usually for small spans is known as:(a) Bridge (b) Tunnel (c) Viaduct (d) Aqueduct

Ans : C45. Creeping of rails will be reduced by using:(a) Bearing plates (b) Spikes (c) Chairs (d) AnchorsAns : D46. The railway track from which a train is to be diverted is called:(a) branch track (b) points and crossing(c) main or through track (d) all aboveAns : C47. An expansion gap of …. is usually kept between the adjoining rail ends to allow for expansion of rail, due tovariation in temperature.(a) 1 to 3 mm (b) 10 to 15 mm(c) 6 to 8 mm (d) 3 to 5 mmAns : C48. Generally the weight/metre of the rails used in broad gauge is:(a) 55 kg (b) 45 kg (c) 35 kg (d) 65 kgAns : A49. A dynamometer car is used for:(a) Tourists (b) Dinning facilities(c) Inspection of administrative officers(d) Recording the condition of trackAns : D50. Which of the following is not a part of rail engine?(a) Tender (b) Stream turbine (c) Boiler (d) Fire boxAns : B

RRB Junior Engineer (Electrical) Model Question Papers

1. A resistance of 10 ohm is connected across a supply of 200V. If resistance R is now connected in parallel with a 10ohm resistance, the current drawn from the supply gets doubled. The value of unknown resistance R is(a) 5 ohm(b) 20 ohm(c) 10 ohm(d) 15 ohmAns : c2. Kirchhoff’s first law is also called as(a) voltage law(b) Current law(c) Mesh Current law(d) All the aboveAns : b3. Find the total resistance when four 3 Ohm resistance are connected in series(a) 3 ohm(b) 12 ohm(c) 14 ohm(d) 8 ohmAns : b4. The practical unit of power is(a) Joule(b) Ampere(c) Watt(d) WeberAns : c5. Form factor of a sine wave is

(a) 1.414(b) 1(c) 0(d) 1.11Ans : d6. The unit of resistance is(a) Mho(b) ohm-m(c) Ohms(d) AmpsAns :c7. Unit of impedance is(a) Ampere(b) Volt(c) Ohm(d) mhoAns : c8. The close path of the flux around any current carrying circuit is referred asCircuit.(a) Magnetic(b) Electric(c) Electromagnetic (d) None of theseAns : a9. The current flowing in an electrical circuit is due to the existence of(a) mmf(b) emf(c) Resistance(d) ReluctanceAns : b10. The magnetic flux flow through a magnetic circuit is due to(a) mmf(b) emf(c) Resistance(d) ReluctanceAns : a11. The on-line UPS is also called asa. Stand-by UPSb. Line Interactive UPSc. Off line UPSd. Current line UPSAns. b12. ________ is used to convert alternating current to direct current.a. Transformerb. Diodec. Resistord. TransistorAns. b13. The supply voltage varies sinusoid ally and has a frequency __________ Hz.a. 60b. 50c. 20d. 10Ans. b14. Expression for magneto-motive force is(a) N/I(b) 1/NI(c) I/N(d) INAns : d15. Unit of mmf is(a) Ampere /Volt

(b) Ampere- turns(c) Volt(d) Volt/AmpereAns : b16. Magnetic field strength is equal to(a) mmf. L(b) L/ mmf(c) mmf/ L(d) 1/mmf.LAns : c17. Peak inverse voltage of bridge rectifier is as that of centre-tap circuit.a. Sameb. Twicec. Halfd. Four timesAns. c18. Peak Resistance of the diode is increased whena. Forward biasedb. Reverse biasedc. Both forward and reverse biasedd. Either a or bAns. b19. The number of lines of force passing through the secondary coil S when unit current changes in the primary coil Pare called(a) Self inductance(b) Mutual inductance(c) Self induction(d) Mutual inductionAns : c20. Unit of flux(a) Amp- turns(b) Weber(c) Volts(d) AmpsAns : b

Engineeers India Limited(EIL) Latest Technical Questions for new Management Trainee Exam

-2012

Q.1 The two windings of a transformer is

(A) conductively linked. (B) inductively linked. (C) not linked at all. (D) electrically linked.

Ans : B

Q.2 A salient pole synchronous motor is running at no load. Its field current is switched off. The motor will

(A) come to stop.

(B) continue to run at synchronous speed.

(C) continue to run at a speed slightly more than the synchronous speed.

(D) continue to run at a speed slightly less than the synchronous speed.

Ans: B

Q.3 The d.c. series motor should always be started with load because

(A) at no load, it will rotate at dangerously high speed.

(B) it will fail to start.

(C) it will not develop high starting torque.

(D) all are true.

Ans: A

Q.4 The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load speed is about

(A) 50 Hz. (B) 20 Hz.

(C) 2 Hz. (D) Zero.

Ans: C

Q.5 In a stepper motor the angular displacement

(A) can be precisely controlled.

(B) it cannot be readily interfaced with micro computer based controller.

(C) the angular displacement cannot be precisely controlled.

(D) it cannot be used for positioning of work tables and tools in NC machines.

Ans: A

Q.6 The power factor of a squirrel cage induction motor is

(A) low at light load only.

(B) low at heavy load only.

(C) low at light and heavy load both.

(D) low at rated load only.

Ans: A

Q.7 The generation voltage is usually

(A) between 11 KV and 33 KV.

(B) between 132 KV and 400 KV.

(C) between 400 KV and 700 KV.

(D) None of the above.

Ans: A

Q.8 When a synchronous motor is running at synchronous speed, the damper winding produces

(A) damping torque.

(B) eddy current torque.

(C) torque aiding the developed torque.

(D) no torque.

Ans: D

Q.9 If a transformer primary is energised from a square wave voltage source, its output voltage will be

(A) A square wave.

(B) A sine wave.

(C) A triangular wave.

(D) A pulse wave.

Ans: A

Q.10 In a d.c. series motor the electromagnetic torque developed is proportional to

(A) Ia . (B) I2a .

(C)I/1a

(D)1/l2a

Ans: B

Q.11 In a 3 – phase induction motor running at slip ‘s’ the mechanical power developed in terms of air gap power Pg is

(A) ( ) s −1 Pg .

(B) Pg/(1 - s)

(C) (1− s) Pg .

(D) s × Pg .

Ans: C

Q.12 In a 3 – phase induction motor the maximum torque

(A) is proportional to rotor resistance r .

(B) does not depend on r .

(C) is proportional tosqrt( r ).

(D) is proportional to r2 .

Ans: B

Q.13 In a d.c. machine, the armature mmf is

(A) stationary w.r.t. armature.

(B) rotating w.r.t. field.

(C) stationary w.r.t. field.

(D) rotating w.r.t. brushes.

Ans: C

Q.14 In a transformer the voltage regulation will be zero when it operates at

(A) unity p.f.

(B) leading p.f.

(C) lagging p.f.

(D) zero p.f. leading.

Ans: B

Q.15 The maximum power in cylindrical and salient pole machines is obtained respectively at load angles of

(D) 90'0 ,< 90'0 .

Ans: D

Q.16 The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The secondary output voltage will be

(A) 3.6 V.

(B) 2.5 V.

(C) 3.0 V.

(D) 6.0 V.

Ans: C

Q.17 The emf induced in the primary of a transformer

(A) is in phase with the flux.

(B) lags behind the flux by 90 degree.

(C) leads the flux by 90 degree.

(D) is in phase opposition to that of flux.

Ans: C

Q.18 The relative speed between the magnetic fields of stator and rotor under steady state operation is

zero for a

(A) dc machine.

(B) 3 phase induction machine.

(C) synchronous machine.

(D) single phase induction machine.

Ans: all options are correct

Q.19 The current from the stator of an alternator is taken out to the external load circuit through

(A) slip rings.

(B) commutator segments.

(C) solid connections.

(D) carbon brushes.

Ans: C

Q.20 A motor which can conveniently be operated at lagging as well as leading powerfactors is the

(A) squirrel cage induction motor.

(B) wound rotor induction motor.

(C) synchronous motor.

(D) DC shunt motor.

Ans: C

Q.21 A hysteresis motor

(A) is not a self-starting motor.

(B) is a constant speed motor.

(C) needs dc excitation.

(D) can not be run in reverse speed.

Ans: B

Q.22 The most suitable servomotor for low power applications is

(A) a dc series motor.

(B) a dc shunt motor.

(C) an ac two-phase induction motor.

(D) an ac series motor.

Ans: B

Q.23 The size of a conductor used in power cables depends on the

(A) operating voltage.

(B) power factor.

(C) current to be carried.

(D) type of insulation used.

Ans: C

Q.24 Out of the following methods of heating the one which is independent of supply frequency is

(A) electric arc heating

(B) induction heating

(C) electric resistance heating(C) electric resistance heating

(D) dielectric heating

Ans: C

Q.25 A balanced three-phase, 50 Hz voltage is applied to a 3 phase, 4 pole, induction motor. When the motor is delivering rated output, the slip is found to be 0.05. The

speed of the rotor m.m.f. relative to the rotor structure is

(A) 1500 r.p.m.

(B) 1425 r.p.m.

(C) 25 r.p.m.

(D) 75 r.p.m.

Ans: D

NS = 120f /P = 120 x 50 /4 =1500rpm

N = NS ( 1-s) = 1500 (1-0.05) = 1425

relative speed = 1500 – 1425 = 75 rpm

Q.26 An alternator is delivering rated current at rated voltage and 0.8 power-factor lagging case. If it is required to deliver rated current at rated voltage and 0.8 power-factor leading, the required excitation will be

(A) less.

(B) more.

(C) more or less.

(D) the same.

Ans: B

Q.27 Over excitation gives leading power factor and under excitation gives lagging p.f . A ceiling fan uses

(A) split-phase motor.

(B) capacitor start and capacitor run motor.

(C) universal motor.

(D) capacitor start motor.

Ans: D

Q.28 A stepper motor is

(A) a dc motor.

(B) a single-phase ac motor.

(C) a multi-phase motor.

(D) a two phase motor.

Ans: D

Q.29 The ‘sheath’ is used in cable to

(A) provide strength to the cable.

(B) provide proper insulation.

(C) prevent the moisture from entering the cable.

(D) avoid chances of rust on strands.

Ans: A

Q.30 The drive motor used in a mixer-grinder is a

(A) dc motor.

(B) induction motor.

(C) synchronous motor.

(D) universal motor.

Ans: D

Q.31 A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance

across the secondary. Assuming 100% efficiency, the primary current equals

(A) 0.2 Amp.

(B) 5 Amps.

(C) 10 Amps.

(D) 20 Amps.

Ans: A

Q.32 A 50 Hz, 3-phase induction motor has a full load speed of 1440 r.p.m. The number of poles of the motor are

(A) 4.

(B) 6.

(C) 12.

(D) 8.

Ans: A

Q.33 In a 3-phase synchronous motorQ.33 In a 3-phase synchronous motor

(A) the speed of stator MMF is always more than that of rotor MMF.

(B) the speed of stator MMF is always less than that of rotor MMF.

(C) the speed of stator MMF is synchronous speed while that of rotor MMF is zero.

(D) rotor and stator MMF are stationary with respect to each other.

Ans: D

Q34.In a capacitor start single-phase induction motor,the capacitor is connected

(A) in series with main winding.

(B) in series with auxiliary winding.

(C) in series with both the windings.

(D) in parallel with auxiliary winding.

Ans: B

Q35.A synchro has

(A) a 3-phase winding on rotor and a single-phase winding on stator.

(B) a 3-phase winding on stator and a commutator winding on rotor.

(C) a 3-phase winding on stator and a single-phase winding on rotor.

(D) a single-phase winding on stator and a commutator winding on rotor.

Ans: C

Q.36 As the voltage of transmission increases, the volume of conductor

(A) increases.

(B) does not change.

(C) decreases.

(D) increases proportionately.

Ans: C

Q.37 The size of the feeder is determined primarily by

(A) the current it is required to carry.

(B) the percent variation of voltage in the feeder.

(C) the voltage across the feeder.

(D) the distance of transmission.

Ans: A

Q. 38 The boundary of the protective zone is determined by the

(A) Location of CT

(B) sensitivity of relay used

(C) Location of PT

(D) None of these

Ans: B

Q.39 In a three phase transformer, if the primary side is connected in star and secondary side is

connected in delta, what is the angle difference between phase voltage in the two cases.

(A) delta side lags by -30°.

(B) star side lags by -30°.

(C) delta side leads by 30°.

(D) star side leads by -30°.

Ans: C

Q.40 This is vector group and has +30° displacement. Therefore, delta side leads by +30°.

Q.43 To achieve low PT error, the burden value should be ____________.

(A) low

(B) high

(C) medium

(D) none of the above

Ans: A

Q.41 Slip of the induction machine is 0.02 and the stator supply frequency is 50 Hz. What will be the

frequency of the rotor induced emf?

(A) 10 Hz.

(B) 50 Hz.

(C)1 Hz.

(D) 2500 Hz.

Ans:c

Q.42 A 4 pole lap wound dc shunt motor rotates at the speed of 1500 rpm, has a flux of 0.4 mWb and the total number of conductors are 1000. What is the value of emf?

(A) 100 Volts.

(B) 0.1 Volts.

(C) 1 Volts.

(D) 10 Volts.

Ans: D

Q.43 The synchronous reactance of the synchronous machine is ______________.

(A) Ratio between open circuit voltage and short circuit current at constant fieldcurrent

(B) Ratio between short circuit voltage and open circuit current at constant field current

(C) Ratio between open circuit voltage and short circuit current at different field current

(D) Ratio between short circuit voltage and open circuit current at different field current

Ans. A

Q.44 A 3 stack stepper motor with 12 numbers of rotor teeth has a step angle of ____________.

(A) 12°

(B) 8°

(C) 24°

(D) 10°

Ans. D

Q.45 In case of a universal motor, torque pulsation is minimized by _________.

(A) load inertia

(B) rotor inertia

(C) both rotor and load inertia

(D) none of the above

Ans: C

HAL TYPICAL QUESTIONS & ANSWERS OBJECTIVE TYPE QUESTIONS ,HAL electronics and

electrical questions and answers,

Q.1 The two windings of a transformer is

(A) conductively linked.

(B) inductively linked.

(C) not linked at all.

(D) electrically linked.

Ans : B

Q.2 A salient pole synchronous motor is running at no load. Its field current is switched off. The motor will

(A) come to stop.

(B) continue to run at synchronous speed.

(C) continue to run at a speed slightly more than the synchronous speed.

(D) continue to run at a speed slightly less than the synchronous speed.

Ans: B

Q.3 The d.c. series motor should always be started with load because

(A) at no load, it will rotate at dangerously high speed.

(B) it will fail to start.

(C) it will not develop high starting torque.

(D) all are true.

Ans: A

Q.4 The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full

load speed is about

(A) 50 Hz.

(B) 20 Hz.

(C) 2 Hz.

(D) Zero.

Ans: C

Q.5 In a stepper motor the angular displacement

(A) can be precisely controlled.

(B) it cannot be readily interfaced with micro computer based controller.

(C) the angular displacement cannot be precisely controlled.

(D) it cannot be used for positioning of work tables and tools in NC machines.

Ans: A

Q.6 The power factor of a squirrel cage induction motor is

(A) low at light load only.

(B) low at heavy load only.

(C) low at light and heavy load both.

(D) low at rated load only.

(D) low at rated load only.

Ans: A

Q.7 The generation voltage is usually

(A) between 11 KV and 33 KV.

(B) between 132 KV and 400 KV.

(C) between 400 KV and 700 KV.

(D) None of the above.

Ans: A

Q.8 When a synchronous motor is running at synchronous speed, the damper winding produces

(A) damping torque.

(B) eddy current torque.

(C) torque aiding the developed torque.

(D) no torque.

Ans: D

Q.9 If a transformer primary is energised from a square wave voltage source, its output voltage will be

(A) A square wave.

(B) A sine wave.

(C) A triangular wave.

(D) A pulse wave.

Ans: A

Q.10 In a d.c. series motor the electromagnetic torque developed is proportional to

Q.11 In a 3 – phase induction motor running at slip ‘s’ the mechanical power developed in terms of air gap

power Pg is

Q.12 In a 3 – phase induction motor the maximum torque

Q.13 In a d.c. machine, the armature mmf is

(A) stationary w.r.t. armature.

(B) rotating w.r.t. field.

(C) stationary w.r.t. field.

(D) rotating w.r.t. brushes.

Ans: C

Q.14 In a transformer the voltage regulation will be zero when it operates at

(A) unity p.f.

(B) leading p.f.

(C) lagging p.f.

(D) zero p.f. leading.

Ans: B

Q.15 The maximum power in cylindrical and salient pole machines is obtained respectively at load angles

of

Q.16 The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The

secondary output voltage will be

(A) 3.6 V.

(B) 2.5 V.

(C) 3.0 V.

(D) 6.0 V.

Ans: C

Q.17 The emf induced in the primary of a transformer

(A) is in phase with the flux.

(B) lags behind the flux by 90 degree.

(C) leads the flux by 90 degree.

(D) is in phase opposition to that of flux.

Ans: C

Q.18 The relative speed between the magnetic fields of stator and rotor under steady state operation is

zero for a

(A) dc machine.

(B) 3 phase induction machine.

(C) synchronous machine.

(C) synchronous machine.

(D) single phase induction machine.

Ans: all options are correct

Q.19 The current from the stator of an alternator is taken out to the external load circuit through

(A) slip rings.

(B) commutator segments.

(C) solid connections.

(D) carbon brushes.

Ans: C

Q.20 A motor which can conveniently be operated at lagging as well as leading power factors is the

(A) squirrel cage induction motor.

(B) wound rotor induction motor.

(C) synchronous motor.

(D) DC shunt motor.

Q.21 A hysteresis motor

(A) is not a self-starting motor.

(B) is a constant speed motor.

(C) needs dc excitation.

(D) can not be run in reverse speed.

Ans: B

Q.22 The most suitable servomotor for low power applications is

(A) a dc series motor.

(B) a dc shunt motor.

(C) an ac two-phase induction motor.

(D) an ac series motor.

Ans: B

Q.23 The size of a conductor used in power cables depends on the

(A) operating voltage.

(B) power factor.

(C) current to be carried.

(D) type of insulation used.

Ans: C

Q.24 Out of the following methods of heating the one which is independent of supply frequency is

(A) electric arc heating

(B) induction heating

(C) electric resistance heating

(D) dielectric heating

Ans: C

Q.25 A two-winding single phase transformer has a voltage regulation of 4.5% at full-load nand unity

power-factor. At full-load and 0.80 power-factor lagging load the voltage regulation will be

(A) 4.5%.

(B) less than 4.5%.

(C) more than 4.5%.

D) 4.5% or more than 4.5%.

Ans: C

Q.26 In a dc shunt motor the terminal voltage is halved while the torque is kept constant. The resulting

approximate variation in speed 'ω' and armature current I' ' a will be

(A) Both ω and aI are doubled.

(B) ω is constant and a I is doubled.

(C) ω is doubled while a I is halved.

(D) ω is constant but

Ans: B

Q.27 A balanced three-phase, 50 Hz voltage is applied to a 3 phase, 4 pole, induction motor. When the motor is delivering rated output, the slip is found to be 0.05. The speed of the rotor m.m.f. relative to the rotor structure is

(A) 1500 r.p(B) (A) 1500 r.p.m. (C) (B) 1425 r.p.m. (D) (C) 25 r.p.m. (E) (D) 75 r.p.m.

Ans: D

Q.28 An alternator is delivering rated current at rated voltage and 0.8 power-factor lagging case. If it is

required to deliver rated current at rated voltage and 0.8 power-factor leading, the required excitation will

be

(A) less.

(B) more.

(C) more or less.

(D) the same.

Ans: B

Q.29 A ceiling fan uses

(A) split-phase motor.

(B) capacitor start and capacitor run motor.

(C) universal motor.

(D) capacitor start motor.

Ans: D

To give starting torque and to maintain speed.

Q.30 A stepper motor is

(A) a dc motor.

(B) a single-phase ac motor.

(C) a multi-phase motor.

(D) a two phase motor.

Ans: D

Stepper motor works on 1-phase-ON or 2-phase –ON modes of operation

Q.31 The ‘sheath’ is used in cable to

(A) provide strength to the cable.

B) provide proper insulation.

(C) prevent the moisture from entering the cable.

(D) avoid chances of rust on strands.

Ans: A

The sheath in underground cable is provided to give mechanical strength.

Q.32 The drive motor used in a mixer-grinder is a

(A) dc motor.

(B) induction motor.

(C) synchronous motor.

(D) universal motor.

Ans: D

Q.33 A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the

secondary. Assuming 100% efficiency, the primary current equals (A) 0.2 Amp.

(B) 5 Amps.

(C) 10 Amps.

(D) 20 Amps.

Ans: A

I1= V1 /R1 = 120/600 = 0.2 (η = 100%, losses are zero ∴V1 = VR = I1R1)

Q.34 A dc shunt generator has a speed of 800 rpm when delivering 20 A to the load at the terminal

voltage of 220V. If the same machine is run as a motor it takes a line of 20A from 220V supply. The speed

of the machine as a motor will be

(A) 800 rpm.

(B) more than 800 rpm.

(C) less than 800 rpm.

(D) both higher or lower than 800 rpm.(D) both higher or lower than 800 rpm.

Ans: C

Ng= Eg (60A / Φpz) Eg = V + Ia Ra ; in generator

Nm= Eb (60A / Φpz) Eb = V - Ia Ra ; in motor

Eg > E b for same terminal voltage

Therefore, Ng > N m

Q.35 A 50 Hz, 3-phase induction motor has a full load speed of 1440 r.p.m. The number of poles of the

motor are

A) 4.

(B) 6.

(C) 12.

(D) 8.

Ans: A

N= Ns (1-S) = NS –NS x S

1440 = Ns

(1-S)

Ns = 1440 / (1-S)

Ns = (120 f/ p) = 120 x 50/p = 6000 p

Nswill be closer to N i.e 1440

When P=2 ; Ns = 3000 rpm , not close to N

When P=4 ; Ns = 1500 rpm , it is closer to N

Q. 36 In a 3-phase synchronous motor

(A) the speed of stator MMF is always more than that of rotor MMF.

(B) the speed of stator MMF is always less than that of rotor MMF.

(C) the speed of stator MMF is synchronous speed while that of rotor MMF is zero.

(D) rotor and stator MMF are stationary with respect to each other.

Ans: D

Because, Motor is magnetically locked into position with stator, the rotor poles are engaged with stator

poles and both run synchronously in same direction Therefore, rotor & stator mmf are stationary w.r.t each

other.

Q.37 In a capacitor start single-phase induction motor, the capacitor is connected

(A) in series with main winding.

(B) in series with auxiliary winding.

(C) in series with both the windings.

(D) in parallel with auxiliary winding.

Ans: B

To make single phase motor self start. We split the phases at 90 degree. Hence, motor behaves like a two phase motor. Q.38 A synchro has

(A) a 3-phase winding on rotor and a single-phase winding on stator.

(B) a 3-phase winding on stator and a commutator winding on rotor.

(C) a 3-phase winding on stator and a single-phase winding on rotor.

(D) a single-phase winding on stator and a commutator winding on rotor.

Ans: C

Synchros : The basic synchro unit called a synchro transmitter. It’s construction similar to that of a Three

phase alternator.

Q.39 As the voltage of transmission increases, the volume of conductor

(A) increases.

(B) does not change.

(C) decreases.

(D) increases proportionately.

Ans: C

Decreases due to skin effect.

Q.40 The size of the feeder is determined primarily by

(A) the current it is required to carry.

(B) the percent variation of voltage in the feeder.

(C) the voltage across the feeder.

(D) thedistance oftransmission.

Ans: A

IOCL PART - I TYPICAL QUESTIONS & ANSWERS OBJECTIVE TYPE QUESTIONS

Q.1 The two windings of a transformer is

(A) conductively linked.

(B) inductively linked.

(C) not linked at all.

(D) electrically linked.

Ans : B

Q.2 A salient pole synchronous motor is running at no load. Its field current is switched off. The motor will

(A) come to stop.

(B) continue to run at synchronous speed.

(C) continue to run at a speed slightly more than the synchronous speed.

(D) continue to run at a speed slightly less than the synchronous speed.

Ans: B

Q.3 The d.c. series motor should always be started with load because

(A) at no load, it will rotate at dangerously high speed.

(B) it will fail to start.

(C) it will not develop high starting torque.

(D) all are true.

Ans: A

Q.4 The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load speed is

about

(A) 50 Hz.

(B) 20 Hz.

(C) 2 Hz.

(D) Zero.

Ans: C

Q.5 In a stepper motor the angular displacement

(A) can be precisely controlled.

(B) it cannot be readily interfaced with micro computer based controller.

(C) the angular displacement cannot be precisely controlled.

(D) it cannot be used for positioning of work tables and tools in NC machines.

Ans: A

Q.6 The power factor of a squirrel cage induction motor is

(A) low at light load only.

(B) low at heavy load only.

(C) low at light and heavy load both.

(D) low at rated load only.

Ans: A

Q.7 The generation voltage is usually

(A) between 11 KV and 33 KV.

(B) between 132 KV and 400 KV.

(C) between 400 KV and 700 KV.

(D) None of the above.

Ans: A

Q.8 When a synchronous motor is running at synchronous speed, the damper winding produces

(A) damping torque.

(B) eddy current torque.

(C) torque aiding the developed torque.

(D) no torque.

Ans: D

Q.9 If a transformer primary is energised from a square wave voltage source, its output voltage will be

(A) A square wave.

(B) A sine wave.

(C) A triangular wave.

(D) A pulse wave.

Ans: A

Q.10 In a d.c. series motor the electromagnetic torque developed is proportional to

(A)1a

(B)12a

(C)1/1a

(D)1/12a

Ans: B

Q.11 In a 3 – phase induction motor running at slip ‘s’ the mechanical power developed in terms of air gap power Pg is

(A)(s-1)Pg

(B)Pg/1-S

(C)1-SPg-Answer

(D)S.Pg.

In a 3 – phase induction motor the maximum torque

(A) is proportional to rotor resistance

(B) does not depend on

(C) is proportional to

(D) is proportional to

Q.13In a d.c. machine, the armature mmf is

(A) stationary w.r.t. armature.

(B) rotating w.r.t. field.

(C) stationary w.r.t. field.

(D) rotating w.r.t. brushes.

Ans: C

Q.14In a transformer the voltage regulation will be zero when it operates at

(A) unity p.f.

(B) leading p.f.

(C) lagging p.f.

(D) zero p.f. leading.

Ans: B

Q.15 The maximum power in cylindrical and salient pole machines is obtained respectively at load angles of Q.16 The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. The

secondary output voltage will be

(A) 3.6 V.

(B) 2.5 V.

(C) 3.0 V.

(D) 6.0 V.

Ans: C

Q.17 The emf induced in the primary of a transformer

(A) is in phase with the flux.

(B) lags behind the flux by 90 degree.

(C) leads the flux by 90 degree.

(D) is in phase opposition to that of flux.

Ans: C

Q.18 The relative speed between the magnetic fields of stator and rotor under steady state operation is zero for a

(A) dc machine.

(B) 3 phase induction machine.

(C) synchronous machine.

(D) single phase induction machine.

Ans: all options are correct

Q.19 The current from the stator of an alternator is taken out to the external load circuit through

(A) slip rings.

(B) commutator segments.

(C) solid connections.

(D) carbon brushes.

Ans: C

Q.20 A motor which can conveniently be operated at lagging as well as leading power factors is the

(A) squirrel cage induction motor.

(B) wound rotor induction motor.

(C) synchronous motor.

(D) DC shunt motor.

Ans: C

Q.21 A hysteresis motor

(A) is not a self-starting motor.

(B) is a constant speed motor.

(C) needs dc excitation.

(D) can not be run in reverse speed.

Ans: B

Q.22

The most suitable servomotor for low power applications is

(A) a dc series motor.

(B) a dc shunt motor.

(C) an ac two-phase induction motor.

(D) an ac series motor.

Ans: B

Q.23 The size of a conductor used in power cables depends on the

(A) operating voltage.

(B) power factor.

(C) current to be carried.

(D) type of insulation used.

Ans: C

Q.24 Out of the following methods of heating the one which is independent of supply frequency is

(A) electric arc heating

(B) induction heating

(B) induction heating

(C) electric resistance heating

(D) dielectric heating

Ans: C

Q.25

A two-winding single phase transformer has a voltage regulation of 4.5% at full-load and unity power-factor.

At full-load and 0.80 power-factor lagging load the voltage regulation will be

(A) 4.5%.

(B) less than 4.5%.

(C) more than 4.5%.

(D) 4.5% or more than 4.5%.

Ans: C

POWER SYSTEMS1. For low head and high discharge the hydraulic turbine used isa) Francis turbineb) Kaplan turbinec) Pelton wheeld) none of the aboveans: b2. A Kaplan turbine isa) In ward flow, impulse turbineb) Outward flow reaction turbinec) A high head mixed flow turbined) Low head axial flow turbineans: d3. An hydro-graph indicatesa) The discharge at any time during the period under considerationb) The max. and min. runoff during the periodc) The average run off during the periodd) all the aboveans: d4. As compared to steam-station ,hydro-electric stations have :a) More cost of installationb) Less maintenance and fuel costc) both (a) and (b)d) Low depreciation charges.ans: c

5. The rotor used in alternators of hydro-electric station isa) Cylindrical rotorb) Salient pole rotorc) Non salient pole rotord) Round rotor with ac excitationans: b

6. The cost of fuel transportation is minimum in ______ plant.a) Thermalb) Nuclearc) Hydrod) Dieselans: c7. Which of the following generating stations has minimum running cost.a) Thermal

b) Nuclearc) Hydrod) none of theseans: c8. Which of the following plants have the highest capital costa) Nuclearb) Dieselc) Thermald) noneans: a9. For harnessing low variable water heads, the suitable hydraulic turbine with high percentage of reaction and runner adjustable vanes isa) Kaplanb) Francisc) Peltond) Impellerans: a10. In a Thermal power plant, the feed water coming to the economizer is heated usinga) H.P. steamb) L.P. steamc) direct heat in the furnaced) flue gasesans: d

ANALOG ELECTRONICS 1

11. Notch is also called asa) band-pass filterb) low-pass filterc) high-pass filterd) narrow-band reject filterans: d

12. The filter which exhibits ac equiripple in the pass-band and monotonic characteristic in stop band isa) Buttorworthb) Chebyshevc) Besseld) Ellipticans: a

13. A multiplier which can accept input voltages of either polarity and can produce output voltage of both polarities is calleda) Bi-quadrant multiplierb) four quadrant multiplierc) two quadrant multiplierd) one quadrant multiplierans: c

14. A multiplier is derived using two logarithmic amplifiers and and antilog amplifier . One more section required isa) multiplierb) adderc) subtractord) dividerans: b

15. A frequency multiplier usually operates ina) push-pullb) class Ac) class Bd) class Cans: d

16. FSK demodulation is an application ofa) PLLb) timerc) BPFd) none of the aboveans: a

17. An oscillator whose frequency is changed by a variable dc voltage is known asa) a crystal oscillatorb) a VCOc)  an Armstrong oscillatord) a piezoelectric deviceans: b18. The integrated circuit chip NE/SE 566 is aa) Schmitt triggerb) power amplifierc) video amplifierd) voltage controlled oscillatorans: d19. For a step input , the output of an integrator isa) a pulseb) a triangular waveformc) a spiked) a rampans: d20. The damping factor of a second order active low pass filter to give butterworth response isa) 1.732b) 1.414c) 0.707d) none of the aboveans: b

ELECTRONIC COMPONENTS AND DEVICES 111. The depletion region or space charge region or transition region in a semiconductor P-N junction diode hasa) electron and holes.b) positive ions and electrons.c) positive ions and negative ions.d) no ions, electron or holes.ans. c12. In a p+ n junction diode under reverse bias, the magnitude of electric field is maximum ata) the edge of the depletion region on the p-side.b) the edge of the depletion region on the n-side.c) the p+n junction.d) the centre of the depletion region on the n-side.ans. c

13. A p-n junction has a built-in potential of 0.8 V. The depletion layer width at a reverse bias of 1.2V is the 2 micrometer. For a reverse bias of 7.2V , the depletion layer width will be

a) 4 micrometerb) 4.9 micrometerc) 8 micrometerd) 12 micrometerans. a14. At 300 K for a diode current of 1mA , a certain germanium diode requires a forward bias of 0.1435 V, whereas a certain silicon diode requires a forward bias of 0.718 V, Under the conditions stated above , the closest approximation of the ratio of reverse saturation current in germanium diode to that in silicon diode isa) 1b) 5c) 4 x 10³d) 8 x 10³ans. c15. A silicon PN junction at a temperature of 20 C has a reverse saturation current of 10 ⁰pico-Amperes (pA). The reverse saturation current at 40 C for same bias is approximately⁰a) 30 pAb) 40 pAc) 50 pAd) 60 pAans. b

16. Which of the following is not associated with a p-n junction ?a) Junction Capacitanceb) Charge Storage-Capacitancec) Depletion Capacitanced) Channel Length Modulation.ans. d

17. As the temperature is increased, the voltage across a diode carrying a constant currenta) increasesb) decreasesc) remains constant.d) may increase or decrease depending on the doping levels in the junction.ans. b18. Choose proper substitutes of X and Y to make the following statement correct. Tunnel diode and Avalanche diode are operated in X bias and Y bias respectivelya) X- reverse ,Y-reverseb) X-reverse, Y -forwardc) X-forward, Y- reversed) X-forward, Y-forwardans. c19. Consider the following assertions.S1- For zener effect to occur, a very abrupt junction is required.S2- For quantum tunneling to occur , a very narrow energy barrier is required.which of the following is correct?a) Only S2 is true.b) S1 and S2 are both true but S2 is not a reason for S1c) S1 and S2 are both true and S2 is a reason for S1.d) Both S1 and S2 are false.ans. a

20. A dc power supply has a no-load voltage of 30 V, and a full-load voltage of 25 V at a full load-current of 1A. Its output resistance and load regulation , respectively area) 5 ohm and 20 %b) 25 ohm and 20%c) 5 ohm and 16.7%d) 25 ohm and 16.7 %ans. b

AC MACHINES 111. The core flux of a practical transformer with a resistance loada) is strictly constant  with load changesb) increases linearly with loadc) increases as the square root of the loadd) decreases with increase of loadans: a

12. In a transformer , zero voltage regulation at full load isa) not possibleb) possible at unity power factor loadc) possible at leading power factor loadd) possible at lagging power factor loadans: c

13. A single phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor isa) 86.7%b) 88.26 %c) 88.9%d) 87.8%ans: d

14. The main purpose of performing open-circuit on a transformer is to measure itsa) copper lossb) core lossc) total lossd) insulation resistanceans: b

15. The desirable properties of transformer core material area) low permeability and low hysteresis lossb) high permeability and high hysteresis lossc) high permeability and low hysteresis lossd) low permeability and high hysteresis lossans: c

16. The all -day efficiency of a transformer depends primarily ona) its copper lossb) the amount of loadc) duration of loadd) both b and cans: d

17. The use of higher flux density in the transformer designa) reduces the weight per KVAb) increases the weight per KVAc) has no relation with the weight of

transformerd) none of the aboveans: a

18. What does the the use of higher flux density in the transformer designa) Increase the weight per KVAb) Decrease in weight per KVAc) Reduced iron lossesd) Reduced copper lossesans. b

19. Cores of large power transformers are made from which one of the following ?a) Hot-rolled steelb) Cold-rolled non-grain oriented steel.c) Cold-rolled grain oriented steeld) Ferrite.ans. c

20. Grain oriented laminated sheel steel in transformer reducesa) copper lossb) eddy current lossc) hysteresis lossd) none of the aboveans. c

AC BASICS AND NETWORKS 111. Unit of reactive power isa) VAb) wattc) VARd) ohmans: c12. An ac source of 200V rms supplies active power of 600 W and reactive power of 800 VAR. The rms current drawn from the source isa) 10 Ab) 5 Ac) 3.75 Ad) 2.5 Aans: b13. With the increase in applied frequency , the dielectric loss in a material willa) increaseb) decreasec) remains constantd) becomes zeroans: a

14. In a ac series RLC circuit , the voltage across R and L is 20 V, the voltage across L and C is 9 V and voltage and voltage across RLC is 15 V , What is the voltage across C?a) 7Vb) 12 Vc) 16 Vd) 21 Vans: a

15. The quantity (2 + j9) represents the resistive and reactive components of current drawn by an ac circuit. The phase angle between the applied voltage and current isa) 41.4'b) 53.13'

c) 36.87'd) 46.86'ans: c

16. Under the condition resonance in R-L-C series circuit, the pf of the circuit isa) 0.5 laggingb) 0.5 leadingc) unityd) zeroans: c

17. In a series RLC circuit at resonance , the magnitude of voltage developed across the capacitora) is always zerob) can never be greater that the input voltagec) can be greater than the input voltage however,  it is 90 degrees out of phase with the input voltaged) can be greater than the input voltage and is in phase with the input voltage.ans: c

18. A series R-L-C circuit , the maximum voltage across the capacitor occurs at a frequencya) double the resonant frequencyb) equal to resonant frequencyc) below the resonant frequencyd) none of the aboveans: c

19. In a series R-L-C circuit , the voltage across inductance will be maximuma) at resonant frequencyb) just after resonant frequencyc) just before resonant frequencyd) just before and after resonant frequencyans: b

20. For a series R-L-C circuit , the power factor at the lower power frequency isa) 0.5 laggingb) 0.5 leadingc) unityd) 0.707 leadingans: d

AC BASICS AND NETWORKS 2

21. Q-factor of as series R-L-C circuit possessing resonant frequency of 10 Hz and bandwidth of 5 Hz isa) 0.5b) 2c) 2.5d) 50ans: b

22. When Q-factor of a circuit is high , thena) power factor of the circuit is highb) impedance of the circuit is highc) bandwidth is larged) none of the aboveans: b

23. A high  Q coil hasa) large bandwidthb) high lossesc) low lossesd) flat responseans: c

24. A coil is tuned to resonance at 500 kHz with a resonating capacitor of 36 pf at 250 kHz , the resonance is obtained with resonating capacitor of 160 pf .What is the self-capacitance of the coil?a) 2.66 pfb) 5.33 pfc) 8 pfd) 10.66 pfans: b

DC MACHINES1. The developed electromagnetic force and/or torque in electro mechanical energy conversion system act in a direction that tendsa) to increase the stored energy at constant fluxb) to decrease the stored energy at constant fluxc) to decrease the coenergy at constant mmf.d) to decrease the stored energy at constant mmfans: b

2. For a linear electromagnetic circuit, the following statement is truea) Field energy is equal to the coenergyb) Field energy is greater than the coenergyc) Field energy is lesser than the coenergyd) Coenergy is zeroans: a

3. In an electromechanical energy conversion device, the developed torque depends upona) stator field strength and torque angleb) stator field and rotor field strengthsc) stator field and rotor field strengths and torque angled) stator field onlyans: c

4. In electro mechanical energy conversion devices , a small air gap is left between the stator and rotor in order toa)  reduce the reluctance of the magnetic pathb) increase flux density in the air gapc) permit mechanical clearanced) none of the aboveans: c

5. A rotating electrical machine having its self inductance of both stator and rotor winding's, independent of rotor position will definitely not develop

a) starting torqueb) synchronizing torquec) hysteresis torqued) reluctance torqueans: b6. A circular metallic disc is placed in a vertical magnetic field of constant induction in the downward direction. If the disc is rotated in a horizontal plane , the emf induced will bea) zerob) constant independent of disc sizec) increasing radically in the outward directiond) decreasing radically in the outward directionans: a

7. The emf induced in a conductor rotating in a bipolar field isa) dcb) acc) dc and ac bothd) none of theseans: b

25. A R-L-C resonant circuit has a resonance frequency of 1.5 MHz and a bandwidth of 10kHz . If c= 150pf, then the effective resistance of the circuit will bea)  29.5  ohmb) 14.75 ohmc) 9.4 ohmd) 4.7ohmans: d

ELECTRICAL MACHINE DESIGN1. For a soft magnetic material there will bea) steeply rising magnetization curve.b) relatively narrow and small hysteresis loop.c) less energy loss per cycle of magnetization.d) all the above.  2. Silicon content in iron lamination is kept within 5% as ita) increases hysteresis loss.b) increases cost.c) makes the material brittle.d) reduces the curie point.ans: c

3. For under frequency operation the eddy current lossa) decreases.b) increases.c) remains unchanged.d) cannot be predicted.ans: a.

4. What is the suitable shape of plunger magnet to give almost flat force-stroke characteristics?a) Flat faced .

b) Conical.c) Stepped.d) Tapered.ans: d.5. In a dc machine " contraction coefficient" is used to take into account the reduction ofa) air-gap area due to armature slots.b) iron losses in the teeth due to lower tooth density.c) armature mmf due to armature slots.d) torque due to ventilating duets.ans: a6. Carter's coefficient is applicable for estimatinga) requirements of air-gap mmf.b) flux distribution in air gap.c) length of air gap.d) no-load loss.ans: a7. A lap wound dc machine has 400 conductors and 8 poles. The voltage induced per conductor is 2 volts. The machine generates a voltage ofa) 100 Vb) 200 Vc) 400 Vd) 800 Vans: a8. The yoke of a dc machinea) must be made of magnetic material.b) should preferably be made of magnetic material but can be of non-magnetic material.c) must be made of non-magnetic material.d) is partially made of magnetic material and partially made of non-magnetic material.ans: a.

9. The pole shoes of a dc machinesa) are always laminated.b) are never laminated.c) are sometimes laminated.d) are partially laminated.ans: a

10. Poles of a dc machines are often laminated toa) reduce pulsation loss.b) reduce armature reaction.c) reduce iron weight.d) dissipate more heat.ans: a.

1. Mho relay is usually employed for the protection

of

a) Short lines only

b) Medium lines only

c) Long lines only

d) Any line

Ans: Long lines only

2. A modern power semiconductor device IGBT is combines the characteristics of

a) BJT and MOSFET

b) FCT and GTO

c) SCR and MOSFET

d) SCR and BJT

Ans: BJT and MOSFET

3. For a single-phase a.c. to d.c. controlled rectifier to operate in regenerative mode, which of

the following conditions should be satisfied?

a) Half –controlled bridge, a 90°, source of e.m.f. in load

c) Full-controlled bridge, a > 90°, source of e.m.f. in load

d) Full-controlled bridge, a 90°, source of e.m.f. in load

4. Which is the most suitable power device for high frequency ( more 100 kHz) switching

application?

a) Power MOSFET b) BJT

c) SCR d) UJT

Ans: Power MOSFET

5. In a thyristor Latching current is ________ than Holding current

a) Equal b) Less

c) Greater d) None

Ans: Greater

6. The transfer function of a system is 10/(1+s) when operating as a unity feedback system,

the steady state error to a step input will be

a) 0 b) 1/11 c) 10 d) Infinity

Ans: 1/11

7. Which one of the following statements for a dc machine which is provided with inter pole

winding (IW) as well as compensating winding (CW) is correct

a) Both IW and CW are connected in series with Armature winding

b) Both IW and CW are connected in parallel with Armature winding

c) IW connected in series but CW is connected in parallel with Armature winding

d) CW connected in series but IW is connected in parallel with Armature winding

Ans: Both IW and CW are connected in series with Armature winding

8. A 0-10 mA PMMC ammeter reads 5mA in a circuit; its bottom control spring snaps out

suddenly the meter will now read.

a) 5mA b) 10mA

c) 2.5mA d) 0

Ans: 0

9. A dc cumulatively compounded motor delivers rated load torque at rated speed. If series

field is short circuited, then the armature current and speed will

a) Both increases

b) Both decreases

c) Increases and decreases

d) Decreases and increases

Ans: Both increases

10. Moving coil in dynamometer wattmeter connected

a) In series with fixed coil

b) Across supply

c) In series with load

d) Across load

Ans: Across supply

11. In an induction machine, if the air gap increased

a) Speed will be reduced

b) Efficiency will be improved

c) Power factor will be lowered

d) Breakdown torque will be reduced

Ans: Power factor will be lowered

12. A CRO screen has ten divisions on the horizontal scale. If a voltage signal 5 sin 314t+45

deg)is examined with a line base settings of 5 msec/div, the number of cycles of signal

displayed on the screen will be

a) 0.5 cycles

b) 2.5 cycles

c) 5 cycles

d) 10 cycles

Ans: 2.5 cycles

13. A 3-phase 50HZ SCIM takes a power input of 30 KW at its full load speed of 1440 rpm.

Total stator losses are 1 KW. The slip and rotor ohmic losses at full load are

a) 0.02, 600 W

b) 0.04, 580 W

c) 0.04, 1160 W

d) 0.04, 1200 W

Ans: 0.04, 1160 W

14. Thermocouple is used to measure

a) AC b) DC c) Both d) None

Ans: Both

15. The two watt meters measurement the ratio of two meter readings is –(1-sqrt3):(

1+sqrt3) then the power factor is

a) 1 b) 0.866 c) 0.707 d) 0

Ans: 0.707

16. Hays bridge is used to measure___________ and Schering bridge is used to

measure____________

a) Inductance, Inductance

b) Inductance, Capacitance

c) Capacitance, Inductance

d) Resistance, Capacitance

Ans: Inductance, Capacitance

17. When sine wave is given as input to Schmitt trigger then its generates

a) Sine wave

b) Saw tooth wave

c) Triangle wave

d) Square wave

Ans: Square wave

18. In Gauss Seidel method the following factors are influenced for operation

a) Acceleration factor

b) Selection of slack buss

c) Both

d) None

Ans: Selection of slack buss*

19.

i. (X’+Y’) A. Low-pass filter function

ii. (X’Y’) B. Sum

iii. (XY) C. NAND

D. Carry

E.NOR

a) i-C, ii-E, iii-D

b) i-C, ii-E, iii-B

c) i-C, ii-B, iii-D

d) i-C, ii-E, iii-A

Ans: i-C, ii-E, iii-D

20. The phase lead compensation is used to

a) Increase rise time and decrease overshoot

b) Decrease both rise time and overshoot

c) Increase both rise time and overshoot

d) Decrease rise time and increase overshoot

Ans: Decrease rise time and increase overshoot

21. Voltage feed back amplifier is a

a) Shunt-Shuntb) Shunt-Series

c) Series-Shunt

d) Series- Series

Ans: Shunt-Shunt

22. In microprocessor the next instruction to be executed is stored in

a) Program Counter

b) Stack Pointer

c) Memory Pointer

d) Accumulator

Ans: Program Counter

23. The following element retains it energy after source is disconnected

a) Resister

b) Inductor

c) Capacitor

d) Thermistor

Ans:

24. In series RLC circuit at resonant

a) Voltage is in phase with current

b) Current is maximum

c) Inductive reactance = Capacitive reactance

d) All of the above

Ans: All of the above

25.For RC low pass filter R=100 K ohms, C= 5 micro farads then lower cutt of frequency is

a) 1 K HZ b) 0 HZ

c) 381.3 HZ d) Infinity

Ans:

26. V=100Sin (1000t+46 deg), I=2Sin (1000t+80 deg) what are the elements in the circuit

a) R=30 ohm, L=30 mH

b) R=30 ohm, C=33.3 micro farads

c) R=40 ohm, L=30 mH

d) R=40 ohm, L=33.3 micro farads

Ans: R=40 ohm, L=33.3 micro farads

27. L=10 mH, I=100Sin50t 0

a)

b)

c)

d)

Ans:

28. In dielectric measurement, the dielectric loss is proportional to

a) F b) V c) I d) Vsqr

Ans: Vsqr

29. G(s) = (1-s)/s(s+2) then closed loop transfer function is

a) Unstableb) Stable

c) Marginally stable

d) All

Ans: Stable

30. G(s) = (1+0.5s)/(1+s) find which type of net work it is

a) Lead net work

b) Lag net work

c) Lag – Lead net work

d) Lead – Lag net work

Ans: Lag net work

31. Temperature of electrode in Arc furnace is

a) 1000 deg

b) 1500 deg

c) 1500 deg to 3500 deg

d) 4500 deg

Ans:

32. In bode plot the point which separates the lower and upper frequencies is called

a) Critical point

b) Cut-off point

c)

d)

Ans:

33. Nyquest stability is used to determine

a) Absolute Stability

b) Relative Stability

c) Both

d) None

Ans: Both*

34. When 220V dc shunt alternator generating the voltage at rated value. If direction of

rotation is reversed, then alternator will

a) Build up its voltage with same polarity

b) Build up its voltage with opposite polarity

c) No build up of voltage

d) None

Ans: No build up of voltage

35. Over lap Angle depends on_________

a) Load inductance

b) Loa capacitance

c) Source inductance

d) Source capacitance

Ans: Source inductance

36. Area under speed time curve gives

a) Time b) Speed

c) Distance d) None

Ans: Distance

37. The regulation of Short Transmission lines depends up ona) Distance of line

b) Frequency

c) Power factor

d) All

Ans: Power factor

38. Which of the following plant is having lowest load factor?

a) Diesel Plant

b) Pumped storage Plant

c) Thermal Plant

d) Nuclear Plant

Ans: Diesel Plan

39. For SR latch whent the out put is undesirable

a) 0, 0

b) 1, 0

c) 0, 1

d) 1, 1

Ans: 1, 1

40. For interrupting capacitive currents which Circuit Breaker (CB) is used

a) SF6 CB

b) Oil CB

c) Vacuum CB

d) Air blast CB

Ans: Vacuum CB

41. For V/F control, when frequency is increased in transformer

a) Core loss component current increases, Magnetizing component current decreases

b) Core loss component current increases, Magnetizing component current increases

c) Core loss component current decreases, Magnetizing component current decreases

d) Core loss component current decreases, Magnetizing component current increases

Ans: Core loss component current decreases, Magnetizing component current decreases

42. In ceiling fan the angle between auxiliary winding a main winding is

a) 0 deg

b) 90 deg

c) 180 deg

d) 360 deg

Ans: 90 deg

43. In a shaded pole motor, shaded rings are used to

a) Field flux production

b)

c)

d)

Ans: Field flux production

44. Practical method of improving string efficiency

a) Increasing crass arms length

b) Using different size of insulators

c) Using different insulator materials

d) Using of guard rings

Ans: Increasing crass arms length*

45. In which type of fault all 3-phase components are equala) L-G

b) L-L

c) L-L-G

d) 3-Phase fault

Ans: 3-Phase fault

46. 11/220 KV 100 MVA transformers, the primary base voltage rating is 10 KV then

secondary base KV is

a) 10 KV

b) 220 KV

c) 220/sqrt3

d)

Ans: 220/sqrt3*

47. Water hamming effect is occurs in

a) Surge tank

b) Penstock

c) Turbine

d) Reservoir

Ans: Penstock

48. Transient stability can be improved by

a) By putting series capacitor

b) By using dynamic resister

c) Auto re-closers

d) All of the above

Ans: All of the above

49. If sending end voltage is Vs at no-load in a transmission line then receiving end voltage

is if ABCD parameters of line is given

a) Vs

b) Vs/A

c) 0

d) Infinity

Ans: Vs/A

50. Harmonics are eliminated by using

a) Skewing of rotor

b) Distribution winding

c) Short pitch winding

d) All of the above

Ans: All of the above

51. For parallel operation of transformer at no load, then load shared are equal when

a) Impedance is proportional with respect to own KVA rating

b)

c)

d)

Ans: Impedance is proportional with respect to own KVA rating

52. In Induction motor Slip frequency of rotor current, when rotor speed is Nr. Then rotor

producing slip field rotates with respect to stator is

a) Slip frequency

b) Nr

c) Nsd) None

Ans: Ns

53. Good regulation means

a) Less fluctuations from no-load to full-load

b)

c)

d)

Ans: Less fluctuation from no-load to full-load

54. At dead short circuit at terminals of Alternator then the current I is

a) ZPF Lag

b) ZPF lead

c) Unity power factor

d) 0.8 Power factor lag

Ans: ZPF Lag

55. Full scale Ammeter reading is 10 mA, Voltage across Ammeter is 100 mV. Then for 100 A

measurements the power loss in the circuit is

a) 1 W

b) 10 W

c) 100 W

d) 1000 W

Ans: 10 W*

56. When Alternator excitation increases and machine is operating at lagging power factor

then

a) I increase

b) I decreases

c) No effect on current

d) None

Ans: I increase

57. Flue gases coming out from furnace is first going through

a) Turbine

b) Economizer

c) Air pre-heater

d) Chimney

Ans: Economizer

58. Two alternators rated are 200 KW at 4% regulation, 400 KW 5% regulation operating in

parallel at 50HZ , when supply 600 KW the new frequency is

a) 50

b) 49

c) 51.3

d) 47.7

Ans: 47.7

59. Va and Vb are negative sequence component voltages the difference angle between Va

and Vb with respect to Va is

a) 240 b) 120 c) 180 d) 360

Ans: 12060. 4-Quadrent operation of chopper I is positive but V is may be positive are negative

operates in which quadrant

a) 1 and 2

b) 2 and 3

c) 1 and 3

d) 1 and 4

Ans: 1 and 4

61. Heat convection, radiation, and conduction all are takes place in

a) Ice

b) Boiler

c) Refrigerator

d) Flue gases in pipe

Ans:

62. When moving iron meter is used to measure d.c current what is the disadvantage

a) It calibration in rms value

b)

c)

d)

Ans:

63. When maximum power transfer to load is

a) 20 W b) 50 W c) 100W d) 0W

Ans: 0W

64. Find Zbus Parameters

a) Z11=Z12=Z21= j0.1 ohm, Z22=j0.3 ohm

b)

c)

d)

Ans: Z11=Z12=Z21= j0.1 ohm, Z22=j0.3 ohm

65. Find Z11 and Z12

a) Z11=4 ohm, Z12= 2 ohm

b) Z11=4 ohm, Z12= 5 ohm

c) Z11=5 ohm, Z12= 2 ohm

d) Z11=4 ohm, Z12= 3 ohm

Ans:

66. Current in 5 ohm resister is

a) 10 A b) -10 A c) 5 A d) -5 A

Ans: -10 A

67. Find I in the circuit at t=0+

a) 2 A

b) 5 A

c) 7 A

d) 10 AAns:

8. Find voltage across inductor at t=0+

a) 0 V b) 2.5 V c) 5 V d) 10 V

Ans: 5 V

69. This wave is applied to the PMMC meter, meter reads

a) 0 V b) 3 V c) 2 V d) 1 V

Ans: 1 V

70. Find Vab

a) Zero

b) 50 at an angle of 90 deg

c) 50 at an angle of 90 deg

d) None

Ans:

71. Find E in the circuit

a) 5 V b) 10 V c) 20 V d) None

Ans: None

72. Vab is reference then angle between Vab and Ib is

a) -15 deg

b) 240 deg

c) 180 deg

d) -45 deg

Ans: -15 deg*