bel test paper

8/13/2019 bel test paper

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Paper: BEL Placement Paper(Technical-Electronics Ist)

1. The gray code equivalent ofbinary 1100 is

a. 1011 b. 1101 c. 1010d. 1100

2. A Multiplexer has

a. Multiple inputs and singleoutput

b. Single input and Multipleoutputs

c. Multiple inputs and Multipleoutputs

d. Multiple inputs for Storage ofData

3. A binary half adder

a. Adds two binary digits and

produces their sum and carry

b. Adds half the sum to the carry

c. Adds two binary digits andcarry from previous addition

d. Adds two binary digits at halfthe speed

4. An index register in a computer

is for

a. Arithmetic and logic functions

b. Storage of results

c. Modifying the address

d. Counting the no ofprogrammes

5. An example of volatile memoryis

a. RAM b. ROM c. EPROMd. Magnetic tape

6. Barrier voltage in a P-N junction

is caused by

a. Thermally generated electronsand holes

b. Diffusion of majority carriersacross the junction

c. Migration of minority carriersacross the junction

d. Flow of drift current

7. The temperature coefficient ofan intrinsic semiconductor is

a. Positive b. Negative c.Zero d. Like metals

8. A silicon transistor has aleakage current 1cbo = 1 ma. If the

temp. rises by 50o C the leakagecurrent will be

a. 30ma b. 32ma c. 50ma d. nochange

9. The noise figure of an idealamplifier in decibel is

a. 0.5 b. 0 c. 1 d. 1

0

10. The rise time of an amplifier is200 nsec. Its bandwidth is

a. 70MHz b. 140MHz c. 100MHz d. 1.75Mhz

11. MOSFET operates in

a. Depletion mode only

b. Enhancement mode only


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c. Depletion and enhancementmode

d. None of these of the above

12. A device which behaves likeSCRs is

a. UJT b.Triac c. MOSFET d. SRD

13. A plate modulated class C RFamplifier produces 100 KWof radiated power at 100 %modulation. The modulating audio

amplifier supplies approximately

a. 25KW b. 33KW c. 50KWd. 66KW

14. A 100 MHz FM carrier,modulated by a 5 KHz sine wavedeviates by 50 KHz

If the frequency of the

modulating sine wave is doubled,the deviation will

a. Double b.Half c. Quadruple d. Have nochange

15. Noise generated by a resistor isdependent on

a. Its Value

b. Its temperature

c. Both value and temp

d. None of these

16. A 32 channel 8 bit PCM systemsamples at 8 KHz rate. The overallbit rate in kilobits per second will be

a. 2048 b. 2000 c. 1920d. 64

17. Stub matching eliminatesstanding wave on

a. Load side of the stub

b. Source side of the stub

c. Both sides

d. On the stub

18. A half wave folded dipole has aradiation resistance of

a. 72

W b.50W c. 144W d. 288W

19. Top loading is used in antennasfor

a. Decrease in impedance

b. Increase in bandwidth

c. Increase in effective height

d. Decease the height

20. The term critical frequency inIonospheric propagation is

a. Lowest frequency reflected byIonosphere

b. Highest frequency reflected bythe Ionosphere at vertical incidence

c. Lowest frequency reflected bythe Ionosphere at vertical incidence

d. Lowest communicationfrequency possible

21. The cathode ray oscilloscopecan be used to measure

a. Frequency b. Timeinterval c. Voltage d. All theabove


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22. A wein bridge is used for

measurement of

a. Resistance b. Capacitance c

. Inductance d. Audio frequency

23. The frame rate per second usedin India TV is

a. 60 b. 50 c. 25 d. 30

24. VHF signals are propagated

a. Via the ionosphere

b. Along the ground

c. Through the troposphere

d. By reflection in ionosphere

25. The impedance of a 3 elementyagi antenna is around

a. 75W b. 300W c. 50W

d. 100W

26. A PIN diode is microwave

a. Oscillator b.Mixer c. Detector d. Switch

27. A transmission line of VSWR 2has a reflection coefficient

a. 0.25 b. 0.5 c. 75

d. 0

28. Microwave repeaters aretypically

a. 25 b. 50 c. 75 d. 100Kms apart

29. To overcome fading in a ship-to-ship communication system wecan efficiently use

a. Broadband Antenna

b. Directional Antenna

c. Space Diversity

d. Frequency Diversity

30. Frequency in the UHF range ispropagate by waves of

a. Ground b. sky c.Space d. Surface

31. A duplexer is used to

a. Receive two signals in one

antenna

b. Prevent interference betweentwo antenna

c. Mix two signals to the sameantenna

d. Allow one antenna for bothtransmission and reception

32. Strapping is used in amagnetron to

a. Prevent mode jumping

b. Reduce frequency drift

c. Ensure proper bunching

d. Dissipate heat

33. A rectangular waveguidebehaves like a filter of

a. Band pass b. High pass c.Low pass d. Band stop

34. The signal propagation time inmilliseconds for a geosynchronoussatellite is

a. 540 b. 270 c. 135 d. 100


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35. The silicon solar cell is a

a. Photo conductive

b. Photo emissive

c. Photo voltaic

d. Photo resistive

36. For the national TV and rationetwork, INSAT-IB uses

a. 400MHz b. 2.5GHz c. 2.5and 5GHz d. 4 and 6 GHz

37. A typical fibre-optic detector is

a. Step recovery diode

b. Light emitting diode

c. Avalanche photo diode

d. Field effect transistor

38. A modem is a device used for

a. Digitizing voice data

b. Transmission of data on lines

c. Modulating and demodulatingsignals sent on a line

d. Suppressing noise interference

39. The most effective anti-jamming technique is

a. Frequency hopping

b. Spread Spectrum

c. Frequency synthesis

d. Burst transmission

40. Mono-mode is a term used in

a. Fibre-optics

b. Radar

c. Satellite communication

d. Magnetics

41. Monopulse technique is used in

a. Radar

b. Radio relay

c. Data communication

d. Fibre-optics

42. HDLC is a term for

a. Data communication protocol

b. Synchronizing pulses

c. Gain control in receivers

d. Error checking

43. A gateway

a. Is a place where radars areconnected

b. Permits dissimilar networks tocommunicate

c. Bifurcates the RF path of a

transmitter

d. Is a feeder cable

44. Ethernet is a name of

a. Medium of computercommunication

b. Network for computercommunication

c. Procedures for computer


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communication network

d. Software for computercommunication

45. If several stations in anetwork want to use a singlechannel without interfering with oneanother, the technique used is called

a. Carrier sense

b. Phantom-freeze

c. Packet switching

d. Multiplexing

46. In a monolithic IC, resistors areformed from

a. Ceramic materials

b. Copper

c. P-type semiconductor

d. Aluminium deposition

47. ICs made by sputtering ofmaterials on a ceramic substrate arecalled

a. Monolithic b. Hybrid c.Thick film d. Thin film

48. Two coils (inductors)

connected in series have a combinedinductance of 15mH. Whenterminals of one of the coils arereversed and connected to theother, the combined inductance ismeasured to be 9mH. What is thevalue of mutual inductance

a. 1.5mH b.3mH c.6mH d.12mH

49. If a parallel LC circuit is excitedat frequency less than its resonant

frequency, the nature of its effectiveimpedance is

a. Resistive b. Inductive c.Capacitive d. None of these of

these

50. The wave length of 1 Giga hertzfrequency signal is

a. 10cm b. 30cm c.3cm d. 1cm

51. Which of the followingmicrowave tubes can be consideredas broad band devices

a. Magnetrons

b. Klystrons

c. Reflex klystrons

d. Traveling wave tubes[TWT]

52. Which family of the following

integrated circuits has the highestspeed

a. DTL b. ECL c. TTL d.CMOS

53. The most important feature ofCMOS family of ICs is

a. High speed

b. Small size

c. Low power consumption

d. Low input impedance

54. What is the resolution of 8 bitA/D converter if its full scale voltageis 10v

a. 0.02v b. 0.01 c.0.039v d. 0.078v

55. What value of resistance is to


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be used in LSB of 4 bit weightedladder D/A converter if MSB has 10kW resistor

a. 160k b. 80k c. 240k d. 100k

56. The pulse width of a radartransmitter is 0.6m sec. and thepulse repetition rate is 700 Hz. Theaverage power measured is 420watts. What is the peak power

a. 100KW b. 420KW c.1MW d. None of these

57. The device used for isolating

the transmitter and receiver in aradar system is called

a. Diplexer

b. Duplexer

c. Directional coupler

d. None of these

58. "Baud is

a. Total No. of bits/sec in eachcharacter

b. Reciprocal of shortest signalelement in a character

c. Duration of a character in datatransmission

d. None of these

59. The advantage of Totem poleoutput stage in TTL ICs is

a. Low output impedance

b. Can sink more current

c. Oscillations avoided

d. None of these

60. The capacitance value of avaractor is controlled by

a. A reverse voltage applied to it

b. A series resistance

c. Varying its supply voltage

d. Current through the device

61. Electron volt is equivalent to

a. 3.8 * 10-20 erg

b. 1.602 * 10-12 erg

c. 1.602 * 10-18 erg

d. 1.602 * 10-16 erg

62. The kinetic energy of photoelectrons emitted by a photosensitive surface depends on

a. Intensity of the incidentradiation

b. Wavelength of the incidentradiation

c. Angle of incident of radiation

d. Surface conditions of thesurface

63. Flux is expressed in radio-metric system in

a. Lumens

b. Photons

c. Watts

d. Candles

64. In a three-phase bridgerectifier circuit, the ripple frequency


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is

a. Same as line frequency

b. Twice the line frequency

c. Thrice the line frequency

d. Six times the line frequency

65. Energy stored in a capacitor asa function of voltage is given by

a. CV2

b. 1V2/2C

c. CV2

d. 1V/2C

66. The operational amplifier usedin analog computers have usuallyopen loop flat gain approximatelyupto

a. 1MHz b.100MHz c. 10MHz d. 0.1MHz

67. An oscillator of 350 MHz is fedwith a pulse of rise time 2 n sec. Therise time of the displayed waveformis approximately

a. 1 n sec b. 2.2 n sec c. 2.0n sec d. 1.7 n sec

68. A radar transmits a peak powerof 100 KW with pulse width of 1 msec and a pulse repetition rate of100 KHz. The average output powerof the radar is

a. 100KW b.10KW c.1000KW d. 50KW

69. The incremental inductance ina coil is due to

a. Saturation

b. Superimposed DC

c. Mutual inductance

d. Change of frequency

70. Microwave tube based onvelocity modulation principle is

a. Klystron

b. Magnetron

c. Light house tube

d. Traveling wave tube

71. Noise output from the receiverdecreases uniformly with noise sideband frequency for

a. Frequency modulation

b. Amplitude modulation

c. Pulse amplitude modulation

d. None of these

72. In amplitude modulation themaximum permissible modulationindex is

a. Unity b. 100 c. infinityd. None of these

73. In frequency modulation themaximum permissible modulationindex is

a. Unity b. 50 c.1000 d.no limit

74. In FM transmission andreception, the pre-emphasis and de-emphasis are used to improve the

a. Signal to noise ratio


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84. In AM transmission antenna

current is 8 Ampere at zeromodulation indexes but increased to8.93 Ampere when modulated on

single sine wave. Then the % ofmodulation is approximately

a. 70.1% b. 80.1% c.65.1% d. 10.0%

85. In AM transmission antennacurrent is 8 Ampere at zeromodulation index. At 80%modulation index the antennacurrent will be

a. 10.00A b. 8.72A c. 9.19A d. 9.79A

86. If two sine waves areamplitude modulated withmodulation index m1 and m2, theeffective modulation index is

a. - m12/m22

b. - m1 m2

c. - m12+m22

d. - m22/m12

87. If it is transmitted current andIc is transmitter current at zeromodulation index and thetransmitted current at modulation

index of m will

a. It = Ic -[1+m]

b. It = Ic -[1+m2]

c. It = Ic -[1+m/22]

d. It = Ic-1+m2

88. If Rr is the radiation resistanceand Rd is the lumped resistance,then the antenna efficiency is given

as "

a. (Rr - Rd) / (Rr + Rd)

b. (Rr + Rd) / (Rr " Rd)

c. Rr / (Rr + Rd)

d. Rd / (Rr + Rd)

89. In end fire array, the current

a. Magnitude and phase in eachelement is the same

b. Magnitude is the same but

phase is different in each element

c. Magnitude is different but nophase difference in each element

d. Magnitude and phase aredifferent in each element

90. In a board side array, thecurrent

a. Magnitude and phase in eachelement is the same

b. Magnitude is the same butphase is different

c. Magnitude is different but nophase difference in each element

d. Magnitude and phase are

different in each element

91. Beam width of the 2 metreparaboloid reflector at 6 GHz is

a. 4.5o

b. 9.25o

c. 3.5o

d. 7.75o


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92. The cut of wave length for TEm, n mode is in a wave guide ofdimension a*b is

a. 2/-(m/a)2 +(n/b)2

b. 2- [m/a]2 + [n/b]2

c. -(m/a)2 + (n/b)2 /2

d. - [m/a]2 + [n/b]2

93. For the standard rectangularwaveguide dimension of 4*2 cm theoff wavelength for TM11 mode isapproximately

a. 1.788cm b. 3.576cm c.1.682cm d. 2.546cm

94. In IMPATT diode, the voltageand current are

a. In phase

b. Out off phase by 90o

c. Out off phase by 180o


95. Which of the followingstatement is true

a. Tunnel diode & IMPATT diodeare negative resistance devices

b. Tunnel diode is positiveresistance device and the IMPATTdiode is negative resistance device

c. Tunnel diode is negativeresistance device and the IMPATTdiode is positive resistance device


96. In a SSB modulation systemwith 100% modulation index thepower saving will be

a. 5/6 of carrier power

b. 2/8 of carrier power

c. 5/12 of the carrier power

d. of the carrier power

97. In SSB modulation themodulation index is increased from0.5 to 1.0, then the power will beincreased by

a. 2 times b. 4 times c. 16times d. 32 times

98. 900 rpm is equal to

a. 94.2 rad/sec

b. 47.1 rad/sec

c. 188.4 rad/sec

d. 16.72 rad/sec

99. Darlington pair is used to

a. Increase the voltage gain

b. Increase the current gain

c. Decrease voltage gain

d. Decrease current gain

100. The transfer function of thesystem shown is

a. G(s) / {1 + H(s)}

b. G(s) H(s) / {1 + G(s) H(s)}

c. G(s) / {1 + G(s)H(s)} d. G(s) / G(s) H(s)


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Electronics-I Answers

1. c

2. a

3. a

4. c

5. a

6. b

7. b

8. b

9. b

10. d

11. c

12. b

13. b

14. d

15. c

16. a

17. c

18. d

19. c

20. b

21. d

22. d23. c24. b

25. b

26. d

27. c

28. b

29. d

30. c

31. d

32. a

33. b

34. c

35. c

36. d

37. c

38. c

39. a

40. a

41. a

42. a

43. b

44. b

45. d

46. c

47. d

48. a

49. b

50. b

51. d

52. b

53. c

54. c

55. b

56. c

57. b

58. b

59. a

60. a

61. b

62. b

63. a

64. b

65. c

66. d

67. c

68. b


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69. d

70. a

71. a

72. a

73. b

74. a

75. b

76. a

77. b

78. a

79. a

80. b

81. c

82. b

83. a

84. a

85. c

86. c

87. c

88. c

89. b

90. a

91. c

92. a

93. b

94. c

95. a

96. a

97. b

98. b

99. b

100. C

1. The noise figure of a receiver is ameasure of:

1. Excess noise generated2. Bandwidth of the receiver3. Gain of the receiver4. Operating frequency

2. The ratio receiver is:1. Direct detection type2. Super regenerative type

3. Super heterodyne type4. None of these

3. In an amplitude modulationsystem, the modulation index isdependent upon:

1. Modulating frequency only2. Carrier amplitude only3. Modulating signal amplitude

only4. Modulating and carrier

amplitudes only

4. Image rejection mixer isgenerally used:

1. To reject the unwantedsignal

2. To improve signal amplitude3. To improve noise figure4. To improve conversion loss

5. The value of a resistor creatingthermal noise is doubled. The noise

power generated is therefore:1. Halved2. Quadrapuled3. Doubled4. Unchanged

6. Indicated the false statement:1. HF mixer are generally

noisier than HF amplifier2. Impulse noise voltage is

independent of bandwidth3. Thermal noise is

independent of the frequency atwhich it is measured

4. Industrial noise is usually ofthe impulse type

7. If the carrier of a 100 percentmodulated AM wave is suppressedthe percentage power saving willbe:

1. 50 b. 70 c. 100 d.66.6

8. A balanced modulator produces:1. The carrier and Two side

bands2. The carrier and one side

band3. Two side bands alone4. Carrier and a number of side

bands


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9. The frequency deviation in FMsystem is proportional to:

1. Modulating frequency2. Carrier amplitude3. Modulating signal amplitude

4. None of these

10. In FM, the total transmittedpower is:

1. Dependent on modulatingsignal amplitude

2. Dependent on modulatingfrequency

3. Dependent on modulatingindex

4. Independent of the above

11. The carrier in an FM systemdisappears for the lowestmodulation index of:

1. 0.5 b. 1.0 c.2.4 d. 3.5

12. The difference between phaseand frequency modulation:

1. Is purely theoretical

because they are the same inpractice2. Is too great to make the two

systems compatible3. Lies in the poorer audio

response of phase modulation4. Lies in the different

definition of the modulation index

13. The overall noise figure of twocascaded amplifiers is equal to

1. The algebraic sum of thetwo

2. The sum of the squares ofthe two

3. The square root of theproduct of the two

4. None of these

14. The noise power output of anamplifier is equal to:

1. KTo BFG2. KTo FG3. KTo F/G

4. KTo / FG

15. The effective noise temperatureof an amplifier is equal to

1. (F + 1) To

2. FTo3. (F " 1) To4. None of these

16. The noise figure of an amplifierdepends upon

1. Its bandwidth2. Its gain3. Its operating frequency4. None of these

17. The velocity of electromagneticwave in a coaxial cable is

1. Equal to the velocity in freespace

2. Less than the velocity in freespace

3. Greater than the velocity infree space

4. None of these

18. The standing wave ratio [SWR]in a transmission line:1. Is proportional to the load

impedance2. Is dependent on the source

impedance3. Is a mis-match between the

load and line4. Is a measure of its power

handling capability

19. The standing wave ratio (SWR)is unity in a transmission line if

1. The load impedance is equalto the characteristic impedance ofthe line

2. The load impedance is twicethat of the characteristic impedance

3. The load impedance is halfof the characteristic impedance ofthe line

4. None of these

20. The standing wave voltage node


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along a line repeats at the rate of ifL is the wave length

1.L/4 b.L/2 c.L d.2L

21. A quarter wave line when shortcircuited at the far end behaves like

1. Pure inductor2. Pure capacitor3. Parallel tuned circuit4. Series tuned circuit

22. The stub line used to matchtransmission line with a given loadimpedance is generally

1. Another open circuited line

2. Another short circuited line3. Quarter wave transmission

line4. Half wave transmission line

23. The smith chart generally coversa distance of

1. Quarter wavelength2. Half wavelength3. One wavelength

4. Twice the wavelength

24. The component generally usedto sample a portion of the energytransmitted in a line is

1. Isolator2. Circulator3. Directional coupler4. None of these

25. The return loss in a transmission

line is a measure of1. Loss of the line2. Standing wave ratio3. Characteristic impedance of

the line4. None of these

26. The antenna can be consideredas

1. Matching the source andfree space

2. Matching the source to theline

3. Matching the line and freespace

4. None of these

27. The free space impedance is

approximately equal to1. 177 W2. 277 W3. 377 W4. 50 W

28. The polarization refers to1. The physical orientation of

the radiated wave2. The directional of

propagation of the wave

3. Direction perpendicular tothe propagation of the wave

4. None of these

29. If u & e are the permeability andpermittivity respectively thecharacteristic impedance of themedium is given by

1. ue b. -u/e c. -e/u d. -eu

30. The power density at distance 'r'from an isotropic radiator withtransmitted power P is:

1. P/r22. P/2 p r23. P/4 p r24. None of these

31. Frequencies in the UHF range isnormally propagated by means of

1. Ground waves2. Sky waves3. Surface waves4. Space waves

32. As electromagnetic waves travelin free space, only one of thefollowing can happen to them

1. Absorption2. Attenuation3. Reflection4. Refraction


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33. High frequency waves are1. Absorbed by the F2 layer2. Reflected by the D layer3. Affected by the solar cycle4. Capable of use for long

distance communications on themoon

34. Indicate which one of followingterms applies to troposcatterpropagation

1. SIDS2. Fading3. Fraday rotation4. Atmospheric storms

35. When microwave signals followthe curvature of the earth, this inknown as

1. Faraday effect2. Ducting3. Ionospheric reflection4. Tropospheric scattering

36. An ungrounded antenna near theground:

1. Is unlikely to need an earthmat2. Acts as a single antenna of

twice the height3. Must be horizontally

polarized4. Acts as an antenna array

37. One of the following consists ofnon-resonant antenna:

1. The folded dipole

2. The rhombic antenna3. The end fire array4. The broad side array

38. Balun is:1. A circuit element to connect

balance line to unbalanced antennaor line:

2. A circuit element to connectbalance line to balanced line

3. A circuit element to connectunbalance line to unbalanced line

4. None of these

39. The slotted line is used tomeasure:

1. Standing wave ratio2. Load impedance

3. Source impedance4. None of these

40. In amplitude modulation Ec ( 1+ m Sin Wmt) Sin Wot, each sideband amplitude will be:

1. Ecm/22. Ecm3. Ec/m4. 2Ec/m

41. FM modulation becomesequivalent to AM modulation if

1. FM index is greater than 12. FM index is equal to 13. FM index is very much less

than 14. FM index less than or equal

to 1

42. S/N improvement of FM over

AM, B is the FM modulation index1. 3B2 b.B c.2Bd.B/2

43. Picture transmission in TVemploys

1. Suppressed carriermodulation

2. Vestigial side band3. Single side band4. None of these

44. Sound transmission in TVemploy

1. Amplitude modulation2. Phase modulation3. Frequency modulation4. Pulse amplitude modulation

45. One of the following is anindirect way of generating FM this isthe:

1. Reactance FET modulator2. Varacter divide modulator


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3. Amstrong modulator4. Reactance bipole transistor

modulator

46. The modulation index of AM

wave is changed from 0 to 1. Thetransmitted power is

1. Un-changed2. Halved3. Doubled4. Increased by 50%

47. The isotropic antenna isrepresented by

1. Dipole antenna2. Rhombic antenna

3. Yagi uda antenna4. No such antenna exists in

practice

48. The gain of parabolic reflectorantenna is proportional to

1. The diameter of the reflector2. Square of the diameter of

the reflector3. Aperture area of the feed

4. None of these

49. The parabolic reflector antennaare generally used to

1. Provide high gain2. Provide pencil beam3. Increase bandwidth of

operation4. None of these

50. Cassegrain feed is used with a

parabolic reflector to1. Increase gain of the system2. Increase the bandwidth of

the system3. Reduce the size of the main

reflector4. Allow the feed to be placed

at a convenient point

51. A helical antenna is used forsatellite tracking because of its

1. Circular polarization2. Maneuverability

3. Broad bandwidth4. Good front " to " back ratio

52. The discone antenna is1. A useful direction finding

antenna2. Used as a radar receiving

antenna3. Circularly polarized like

other circular antenna4. Useful as a VHF receiving

antenna

53. Waveguides are used mainly formicrowave signals because

1. They depend on straight line

propagation which applies tomicrowaves only

2. Losses would be too heavyat lower frequencies

3. There are no generatorspowerful enough to excite them atlower frequencies

4. They would be too bulky atlower frequencies

54. The wavelength in a waveguide1. Is greater than in free space2. Depends only on the

waveguide dimensions and the free-space wavelength

3. Less than the free spacewavelength

4. Equal to the free spacewavelength

55. The dominant mode of

propagation is preferres withrectangular waveguidebecause(indicate false statement)

1. It leads to the smallestwaveguide dimensions

2. The resulting impedance canbe matched directly to coaxial lines

3. It is easier to excite thanthe other modes

4. Propagation of it withoutany spurious generation can beensured


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56. The velocity of propagation(group velocity) in a waveguide is

1. Less than the free spacevelocity

2. Greater than the free space

velocity3. Equal to be free space

velocity4. None of these

57. A wave can propagate in awaveguide if its cut off wavelengthis

1. Greater than the free spacewavelength

2. Less than the free space

wavelength3. Equal to be free space

wavelength4. None of these

58. The dominant mode in arectangular waveguide is

1. TE11 b.TE10 c.TE20 d.TM11

59. The characteristic waveimpedance of a waveguide1. Depends on the mode of

propagation2. Does not depend on the

mode of propagation3. Is same as the free space

impedance4. None of these

60. A choke flange may be used to

couple two waveguides1. To help in the alignment of

the waveguides2. Because it is simpler than

any other joint3. To compensate the

discontinuities at the joint4. To increase the bandwidth

of the system

61. The dominant mode in a circularwaveguide is

1.

TE01 b.TE11 c.TM01 d.TM11

62. A ferrite is1. A non-conductor with

magnetic properties2. An inter metallic compound

with particularly good conductivity3. An insulator which heavily

attenuates magnetic fields4. A microwave semiconductor

invented by farady

63. The maximum power that maybe handled by a ferrite component islimited by the

1. Curie temperature2. Saturation magnetization3. Line width4. Gyro magnetic resonance

64. The isolator is1. Bidirectional2. Unidirectional3. Used to tap the power in a

waveguide transmission line

4. Used for None of these ofthe above

65. Isolator is generally used:1. To protect the high power

transmitter2. To protect receiver3. To protect the antenna4. To avoid arcing in

waveguides

66. A TR tube is used1. To protect the high power

transmitter2. To protect receiver3. To avoid arcing in

waveguides4. For None of these of the

above

67. Rieke diagrams are used toselect best operating conditions for

1. TWT amplifier2. Klystron oscillator


18/40

3. Magnetron oscillator4. Cross field amplifiers

68. The gain bandwidth product of amicrowave transistor FT, is the

frequency at which the1. Alpha of the transistor falls

by 3 dB2. Beta of the transistor falls

by 3 dB3. Beta of the transistor falls to

unity4. Power gain of the transistor

falls to unity

69. The cavity magnetron uses

strapping to1. Prevent mode jumping2. Prevent cathode-back

heating3. Ensure bunching4. Improve the phase-

focussing effect

70. The transferred " electron bulkeffect occurs in

1. Germanium2. Gallium arsenide3. Silicon4. Metal semiconductor

junction

71. One of the following is not usedas a microwave mixer or detector

1. Crystal diode2. Schottky " barrier diode3. Backward diode

4. PIN diode

72. SAW devices may be used as:1. transmission media like

stripline2. filters3. UHF amplifiers4. Oscillators at millimeter

frequencies

73. Surface acoustic wavespropagate in:

1. Gallium arsenide

2. Indium phosphide3. Stripline4. Quartz crystal

74. A parametric amplifier has an

input and output frequency of 2.25GHz, and is pumped at 4.5 GHz is a

1. Traveling wave amplifier2. Degenerate amplifier3. Lower-side band up

converter4. Upper-side band up

converter

75. The negative resistance in atunnel diode

1. Is maximum at the peakpoint of the characteristic

2. Is available between thepeak and valley points

3. Is maximum at the valleypoint

4. May be improved by thereverse bias

76. Microwave links repeaters are

typically 50KM apart1. Because of atmosphericattenuation

2. Because of output tubepower limitations

3. Because of Earth's curvature4. To ensure that the applied

voltage is not excessive

77. Microwave links are generallypreferred to coaxial for television

transmission because1. They have less overall phase

distortion2. They are cheaper3. Of their greater bandwidths4. Of their relative immunity to

impulse noise

78. A geostationary satellite1. Is motionless in

space(except for its spin)2. Is not really stationary at

all, but orbits the earth with a 24


19/40

hour period3. Appears stationary over

Earth's magnetic pole4. Is located at a height of

35800KM to ensure global coverage

79. The geostationary satellitelaunched by India are called

1. INTELSAT2. INSAT3. COMSAT4. MARISAT

80. A parametric amplifier must becooled

1. Because parametric

amplification generates a lot of hest2. To increase bandwidth3. Because it cannot operate at

room temperature4. To improve the noise

performance

81. If the peak transmitted power ina Radar system is increased by afactor of 16, the maximum range

will be increased by a factor of1. 2 b.4 c.8 d. 16

82. Telephone traffic is measured1. With echo2. By relative congestion3. In terms of the grade of

service4. In erlangs

83. If the antenna diameter in aradar system is increased by afactor of 4, the maximum range willbe increased by a factor of:

1. -2 b. 2 c.4 d. 8

84. A high PRF will (indicate thefalse statement)

1. Make the returned echoeseasier to distinguish from noise

2. Make target tracking easierwith conical scanning

3. Increase the maximumrange

4. Have no effect on the rangeresolution

85. The bandwidth of a radarreceiver is inversely proportional tothe

1. Pulse width2. Pulse repetition frequency3. Pulse interval4. Square root of the peak

transmitted power

86. If d is the pulse width, T is pulserepetition period and P is the peak

power, the duty ratio is1. T/d b.P/T c.P/d d.d/T

87. If d is the duty ratio and P is thepeak power in a pulsed transmitter,then the average power is

1. P.d b.P.2d c.P/d d. P/2d

88. If the return echo arrives after

the allocated pulse interval1. It will interfere withoperation of the transmitter

2. The receive might beoverloaded

3. It will not be received4. The target will appear closer

than it really is

89. If the target cross section ischanging, the best system for

accurate angle traking is1. Lobe switching2. Sequential lobing3. Conical scanning4. Monopulse

90. After a target has been acquiredthe best scanning system fortracking is

1. Nodding2. Spiral3. Conical4. Helical


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91. The Doppler frequency increasesas the target

1. Approaches the radar2. Recedes the radar

3. Moves perpendicular to thebeam

4. Does not depend on thetarget velocity

92. The Doppler effect is used in(indicate the false statement)

1. Moving target plotting onthe PPI

2. MTI system3. FM Radar

4. CW Radar

93. Solution to the blind speedproblem is to

1. Change the Dopplerfrequency

2. Vary the PRF3. Use monopulse4. Use MTI

94. The A-scope displays1. Target position and range2. Target range but not

position3. Target position but not

range4. Neither range nor position

but only velocity

95. In the colour television systemthe sub carrier frequency in MHz is

approximately

1. 3.58 b.4.5 c.45.75 d. 5.58

96. In television 4: 3 : represents1. The interlace ratio

2. The maximum horizontaldeflection

3. Aspect ratio4. The ratio of the two

diagonals of picture tube

97. Equalizing pulses in TV are sentduring the:

1. Horizontal blanking2. Vertical blanking3. The serrations

4. Horizontal retrace

98. The number of lines per field inIndian television system is:

1. 625 b. 312.5 c.525 d. 262.5

99. The number of frames in IndianTV system is:

1. 50 b. 60 c. 25 d.30

100. In a TV receiver the colourkiller:

1. Cuts off the chromastagesduring monochrome reception

2. Ensures that no colour istransmitted to monochromereceivers

3. Prevents colour overloading4. Makes sure that the colour

burst is not mistaken for sync pulses

Answer:-

1. a

2. c

3. b

4. c

5. b

6. b

7. d

8. c

9. c

10. d

11. c

12. d

13. d

14. a

15. c

16. d

17. b

18. c

19. a


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20. b

21. c

22. b

23. b

24. c

25. b

26. c

27. c

28. c

29. b

30. c

31. d

32. b

33. c

34. b

35. b

36. d

37. b

38. a

39. a

40. a

41. c

42. a

43. b

44. c

45. c

46. d

47. d

48. b

49. b

50. d

51. a

52. d

53. d

54. a

55. b

56. a

57. c

58. b

59. a

60. b

61. c

62. a

63. a

64. b

65. a

66. b

67. c

68. a

69. d

70. b

71. d

72. b

73. d

74. b

75. b

76. c

77. a

78. b

79. b

80. d

81. d

82. a

83. c

84. c

85. a

86. d

87. a

88. d

89. d

90. c

91. a

92. a

93. b

94. b

95. a

96. c

97. b

98. b

99. a

100.a

1. Resistivity of silicon in ohmscm. is approx. equal to

a. 50 b. 1012 c.230k d. 10-6

2. Rsistivity ofGermanium in

ohms cm. is approx. equal to

a. 50 b. 10-12 c.50k d. 10-6

3. The number of freeelectrons/cubic cm intrinsicGermanium at room temperature isapprox. equal to

a. 1.5*1010 b. 2.5*1013 c.


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1000 d. 5*106

4. The number of freeelectrons/cubic cm ofintrinsic silicon at room

temperature is approx. equal to

a. 1.5*1010 b. 2.5*1013 c.10000 d. 5*106

5. The forbidden energy gap forsilicon is

a. 1.1eV b. 067eV c.0.97eV d. 1.7eV

6. The forbidden energy gap forGermanium is

a. 1.1eV b. 067eV c.0.97eV d. 1.7eV

7. N type material is formed bythe addition of the following (pentavalent )atom in n to semiconductormaterial

a. Antimony

b. Arsenic

c. Phosphorous

d. Any of the above

8. P type material is formed bythe addition of the following

[Trivalent] atom tn tosemiconductor material

a. Boron b. Gallium c.Indium d. Any of the above

9. Impurity atoms that producesN type material by its addition insemiconductor is called

a. Donar b. Acceptor c.Conductor d. Insulator

10. Impurity atoms that produces Ptype material by its addition insemiconductor is called

a. Donar b. Acceptor c.

Conductor d. Insulator

11. Dynamic resistance of a diodeRd is if voltage changes is DVd andthe current change is D Id

a. D Vd / D Id

b. D Id / D Vd

c. 1 / DVd

d. 1 / D Id

12. Point contact diodes arepreferred at very high frequency,because of its low junction

a. Capacitance and inductance

b. Inductance

c. Capacitance

13. Identify the circuit given below

a. AND gate

b. OR gate

c. Rectifier

d. NOR gate

14. Identify the circuit given below

a. AND gate

b. OR gate

c. Rectifier

d. NOR gate

15. DC value of a Half wave rectifier


23/40

with Em as the peak value of theinput is

a. 0.318Em

b. 0.418Em

c. 0.518Em

d. 0.618Em

16. Change in Zener voltage of 10Vat 100o C if temperature co-efficientis 0.072%o C as

a. 0.54 V b. 0.74 V c. 0.64

V d. 0.14 V

17. If Tc is th e% temperature co of/ oC and Vz as zener voltage and Tas change in temperature then thechange in zener voltage is

a.

b.

c. 100. Vz. Tc DT


18. PIV for a full wave rectifier, ifEm is the peak voltage is

a. Em b. 1.5Em c.0.636Em d. 2Em

19. Schottky Barrier diodesbecomes important at

a. DC level operation

b. Low frequency operation

c. High frequency operation

d. None of these

20. Clamping network is the onethat will clamp the signal to a

a. Different peak value

b. Different DC level

c. Different polarity level

d. Different RMS level

21. Clipping network is the one thatwill clip a portion of the

a. Input signal without distortingthe remaining portion

b. Input signal with distorting the

remaining portion

c. Any of the above

d. None of these

22. Transition capacitance Ct of aVaricap diode with Knee voltage Vt,reverse voltage Vr and K, theconstant based on semiconductor

material and the constructiontechnique & N dependent on type ofjunction is given by

a. 1 / K (Vt + Vr)N/2

b. 1 / K (Vt + Vr)N

c. K / (Vt + Vr)N

d. K / (Vt + Vr)1/N

23. Ct = K / (Vt + Vr)N where VtKnee voltage, Vr reverse voltage, Kmanufacturing dependent constantand N dependent on typeof junction, for alloy junction thevalue of N is

a. 1/3 b. 2/3 c. 1/2 d. 1/4

24. Ct = K / (Vt + Vr)N where VtKnee voltage, Vr reverse voltage, Kmanufacturing dependent constant


24/40

and N dependent on typeof junction, for diffused junction thevalue of N is

a. 1/3 b. 2/3 c. 1/2 d. 1/4

25. In JFET, the drain current Id isgiven by (Idss drain " sourcesaturation current Vgs " Gate "source voltage, Vp the pinch offvoltage)

a. Idss[1 " Vp/Vgs]

b. Idss(1 " Vgs/Vp)2

c. Idss[1 " Vgs/Vp)

d. Idss(1 " Vgs/Vp)3/2

26. The shadow mask in colour tubeis used to

a. Reduce X-Ray emission

b. Ensure each beam hits its own

dots

c. Increase screen brightness

d. Provide degaussing for thescreen

27. Indicate which of the followingsignal is not transmitted in colourTV

a. Y b. Q c. R d. I

28. Another name for horizontalretrace in TV receiver is the

a. Ringing b. Burst c.Damper d. Fly back

29. Another name for the coloursync in the colour TV system

a. Ringing b. Burst c.Damper d. Fly back

30. The HV anode supply for apicture tube of a TV receiver isgenerated in the

a. Mains transformer

b. Vertical output stage

c. Horizontal output stage

d. Horizontal oscillator

31. The output of vertical amplifieris

a. Direct current

b. Amplified vertical sync pulse

c. A saw tooth voltage

d. A saw tooth current

32. In a transistor if Alpha = 0.98,current gain is equal to

a. 29 b. 59 c. 69 d. 49

33. The active region in thecommon emitter configurationmeans

a. Both collector and emitterjunction is reverse biased

b. The collector junction is

forward biased and emitter junction

c. The collector junction isreverse biased and emitter junctionis forwared biased

d. Both collector & emitterjunction are forward biased

34. The saturation region in thecommon emitter configurationmeans that


25/40

a. Both collector & emitterjunction are reverse biased

b. The collector junction isforward biased and emitter junction

c. The collector junction isreverse biased and emitter junctionis forwared biased

d. Both collector & emitterjunction are forward biased

35. The % of Red, Green & Blue in100% White Y is given by

a. 30%, 59%, 11%

b. 50%, 30%, 11%

c. 30%, 11%, 50%

d. 33.3%, 33.5%, 38.3%

36. Equalizing pulse width, if H isthe Horizontal sync rate

a. 0.64 H b. 0.07 H c. 0.04H d. 0.16 H

37. In a simple RC network thebandwidth is equal to

a. 1/2 p RC

b. RC / 2

c. 2 C / p R

d. 2 p / RC

38. The time constant of a RCnetwork is given by

a. RC b. C/R c. R/C d.None of these

39. First zero crossing of pulsefrequency spectrum occurs at if d isthe pulse width, T is the pulse

repetition rate

a. 1/d b. d/T c. T/d d.T

40. The distortion less outputcharacteristic of a network means

a. Constant amplitude and linearphase shift over frequency

b. Linear phase shift andamplitude need not be constant

c. Any amplitude and phase

d. None of these

41. Single sideband meanssuppressed

a. Carrier

b. Carrier and one side band

c. One side band

d. None of these

42. In an amplitude modulatedsignal, lower side band frequency isequal to (if the carrier frequency isfc and modulation frequency is fm)

a. fm + fc b. fc " fm c. fm rfc d. fc / fm

43. Modulation index of thefrequency modulation depends on

a. Amplitude & frequency of themodulation signal

b. Frequency and amplitude ofcarrier signal

c. Carrier frequency

d. None of these


26/40

44. The BW of the narrow band FMif modulating frequency is fm

a. 3 r fm b. 2 r fm c. 2.5 rfm d. 10 r fm

45. Reactance tube modulator isknown for

a. FM b. AM c. PPM d.PAM

46. Bandwidth and rise timeproduct is

a. 0.35 b. 0.45 c. 0.30 d.

0.49

47. Energy gap, Lg, for Germaniumat room temp [300o K] is

a. 0.72eV b. 1.1eV c.1.53eV d. 0.2eV

48. Volt equivalent of temperatureVT, at 116o K is

a. 0.11V b. 0.01V c.1.16V d. 0.1V

49. Reverse saturation current of aGe.diode is in the range of

a. mA b. uA c.nA d. pA

50. Cut-in voltage V for silicon is

approximately

a. 0.2V b. 0.6V c.0.9V d. 1.1V

51. Every 10o C rise in temp. thereverse saturation current

a. Doubles

b. Halves

c. Triples

d. No change

52. Hall effect with reference toMetal or Semiconductor carrying a

current I is placed in a transversemagnetic field B, an electric field Eis induced in

a. Parallel to B

b. Perpendicular to I

c. Perpendicular to both B & I

d. Perpendicular to B

53. 1 eV (electron volt) is equal to:

a. 1.9 r 10-20 J

b. 1.6 r 10-19 J

c. 1.6 r 10-20 J

d. 1.16 r 10-19 J

54. Donar impurity is having avalency of:

a. 2 b. 3 c. 4 d. 5

55. Acceptor impurity is having avalency of

a. 2 b. 3 c. 4 d. 5

56. Electron volt arises from thefact that if any electron falls througha potential of 1 volt, its kineticenergy will

a. Decrease, & potential energywill increase

b. Increase & potential energydecrease

c. Be unaltered & potentialenergy decreases


27/40

d. Increase & potential energyincrease

57. Hole is created in a

semiconductor material if one offollowing impurities are added

a. Antimony

b. Arsenic

c. Indium

d. Phosphorus

58. Excess electron is created by

a. Boran

b. Gallium

c. Indium

d. Arsenic

59. A snubber circuit is used acrossthe SCR to protect against

a. The di/dt of the anode current

b. The dv/dt turn on

c. L.di/dt of load inductance

d. None of these

60. Germanium has the valency of

a. 2 b. 3 c. 4 d. 5

61. Silicon has the valency of

a. 2 b. 3 c. 4 d. 5

62. Hole acts as a free chargecarrier of polarity

a. Negative

b. Positive

c. Neutral

d. None of these

63. Burst signal in NTSC system is 8cycles of the frequency of

a. Colour sub carrier

b. Picture carrier

c. Sound carrier

d. None of these

64. Colour sub carrier referenceburst is superimposed on the

a. Back porch of the eachhorizontal sync pulse

b. Front porch of the eachhorizontal sync pulse

c. Front porch of the eachvertical sync pulse

d. Back porch of the each verticalsync pulse

65. The law of mass action withreference to semiconductortechnology states that the productof free negative & positiveconcentration is a constant and

a. Independent of amount ofdonor and acceptor doping

b. Dependent on amount of donorand independent of the amountacceptor impurity doping

c. Depend on amount of bothdonor & acceptor impurity doping

d. None of these


28/40

66. The snubber circuit used acrossSCR is a simple

a. R-L network

b. RLC network

c. LC network

d. RC network

67. To limit the rate of rise of SCRanode current a small

a. Inductor is inserted incathode circuit

b. Inductor is inserted in anodecircuit

c. Capacitor is inserted in anodecircuit

d. Capacitor is inserted incathode circuit

68. Torque developed by a DC servomotor is proportional to the

a. Product of power and time

b. Product of armature currentand back emf

c. Armature voltage andarmature current

d. Field voltage and field current

69. Proportional Integral control

a. Reduces steady state errorbut reduces the forward gain

b. Increases the forward gainand reduces the steady state error

c. Increases the steady stateerror and increases the forward gain

d. None of these

70. Increasing the servobandwidth:

a. Improves signal to noise ratio

b. Improves speed response andlowers signal to noise ratio

c. Improves power output

d. None of these

71. Notch filter is

a. Low pass filter

b. High pass filter

c. Narrow stop band filter

d. Narrow pass band filter

72. In TV Receivers the Electronbeam deflection method used is

a. Electro static

b. Electro magnetic

c. Magnetic

d. All the above

73. In a line of sight communicationthe maximum range R in miles

between the receiver antenna andtransmitter antenna of height H infeet is approximately

a. R = 1.93 -H

b. R = 1.23 -H

c. R = 1.53 -H

d. R = 2.03 -H

74. In wavelength of the 60 MHz


29/40

carrier frequency is

a. 10 metres

b. 15 metres

c. 5 metres

d. 2.5 metres

75. In standard TV receivingantenna the dipole element is

a. 0.5 of the wave length

b. 0.25 of the wave length

c. 1.5 of the wave length

d. 1.0 of the wave length

76. The characteristics of FET aresimilar to:

a. Triode

b. Tertode

c. Pentode

d. Diode

77. Charge coupled device is anarray of capacitors whose structureis similar to:

a. Shift register

b. Flip-flop

c. NAND gate

d. Amplifier

78. Operational amplifiercharacteristics are which of thefollowing:

a. Infinite gain

b. Infinite input impedance

c. Output impedance is zero

d. All of the above

79. The typical value of the openloop gain in dB of an amplifier at DCwith no feedback is:

a. 90 to 100

b. 80 to 90

c. 0 to 50

d. 50 to 70

80. The 3 dB band width means thefrequency at which

a. The open loop voltage gainreduced to 0.707

b. The open loop gain reduced tounity

c. Maximum voltage of a signal iswithout distortion

d. It is a medium wave bandwidth of radio receiver

81. Rise time of an amplifier isdefined as time required

a. To change from 0 to 100 % of

its final value

b. To change from 0 to 50 % ofits final value

c. To change from 10 to 90 % ofits final value

d. To change from 10 to 100 % ofits final value

82. High speed amplifier designemphasized on


30/40

a. Extremely small bandwidth

b. Very slow response

c. Unity gain bandwidth after 10MHz

d. None of these

83. Tuned amplifier having thefrequency range between

a. 150 KHz " 50 MHz

b. 100 Hz " 100 KHz

c. 100 KHz " 120 KHz

d. 50 MHz " 100 MHz

84. The resonance frequency of atuned circuit made up of R, L, C isgiven by

a. 1/2 p-LC

b. 2 p-LC

c. 2 p / -LC

d. -LC / 2

85. The voltage follower can beobtained using operational amplifier

a. Without any feedback

b. Series parallel feedback ofunity

c. Parallel feedback

d. Series feedback

86. Fidelity of the amplifier is when

a. It is a linear amplifier

b. It does not add or subtract any

spectral components

c. It amplifier each componentby the same amount

d. All of the above

87. What would be the output whentwo input sine waves of frequency50 KHz and 100 KHz passed throughan amplifier in the medium signal

a. 50 KHz and 100 KHz

b. 100 KHz and 200 KHz

c. 50 KHz and 150 KHz

d. All of the above

88. The important application ofSchmitt trigger is

a. To convert slowly varyinginput voltage to abrupt voltagechange

b. To convert abruptly varyinginput voltage into slowly varyingoutput

c. To change the frequency ofthe input

d. None of these

89. Meaning of decoding is

a. Binary addition

b. Data transmission

c. Demultiplexing

d. Storage of binary information

90. Approximately how manynumber of gates are incorporated inSSL chip


31/40

a. 12

b. 100

c. Excess of 100

d. Excess of 1000

91. The circuit diagram representswhich one of the following

a. Half adder

b. Full adder

c. Exor gate

d. AND gate

92. Flip flop cannot be called as

a. Bistable multivibrator

b. 1 Bit memory unit

c. latch

d. combinational circuit

93. The important use of low passfilter in power supply is

a. To get the regulation in theoutput voltage

b. To filter out the ripplefrequency

c. To increase the current rating

d. To convert AC into DC

94. Binary equivalent of the decimalnumber 145 is

a. 10010001

b. 1001011

c. 1010001

d. 1100010

95. In which of the following gatethe output will be high when all the

maintained at high level

a. NORb. AND

c. NAND

d. EXOR

96. Which of the followingdefinition is true in the De Morgan's

theorem

a. Multiplication symbols arereplaced by addition symbol

b. Addition symbols are replacedby Multiplication symbol

c. Each of the terms areexpressed in the complementary

formd. All of the above97. 8421/BCD code fro a decimalnumber 149 isa. 0001 0100 1001b. 10010101c. 10101001d. None of these98. Combinational circuit are mainlycharacterized bya. Output depends upon the

previous state & presents stateb. Output depends upon the inputat that particular instantc. Output depends upon thepresents state & the clock stated. Output does not depends uponthe input at all99. A flip flop is defined asa. A bistable device with twocomplementary outputsb. It is memory element

c. It will respond to input and it


32/40


33/40

87. a

88. a

89. c

90. a

91. a

92. d

93. b

94. a

95. b

96. d

97. a

98. b

99. d

100.a

1. The register is a1. Simplified unit of a

subtractor2. Cascaded group of the flip-

flop3. Binary ripple counter4. Data selector

2. The energy of the photoelectron depends upon the followingfactor

1. Intensity of incidentradiation

2. Quality of the photocathode3. Frequency of incident

radiation4. Type of the incident light

source3. Hall effect is used to determine

1. Magnetic flux

2. Current density3. Type of semiconductor

material4. All of the above

4. Which one of the following isthe thermistor

1. Semiconductor device2. Microwave device3. Platinum resistance

thermometer4. Thermo-couple device

5. Silicon is having direct band gap1. True2. False3. No gap4. None of these

6. Boron is doped in silicon to form1. P-type2. N-type3. Intrinsic4. None of these

7. The concentration of impurity indoped silicon semiconductor per

atom is1. 1018 b.

1022 c.108 d.10-228. Conduction in P-type

semiconductor is due to1. Movement of hole2. Movement of electron3. Movement of atoms4. Movement of electron-hole

pair9. Slope of electrical conductivity

Vs temperature in semiconductor is1. Positive2. Negative3. Linear4. No effect

10. Volt equivalent of temperatureof silicon at room temperature (300deg K) is

1. 0.7V b. 1.1V c.0.026V d. 16V11. Carbon is not used as

semiconductor because1. It does not belong to silicon

group2. It is a good conductor3. It is not a conductor4. Band gap is very high

12. In forward bias of P-N junctiondepletion region

1. Increases2. Decreases3. Remains the same4. Breaks down

13. Knee voltage in diode standsfor

1. Reverse break down voltage2. Saturation voltage3. Threshold of current

conduction

4. Peak inverse voltage14. An ideal semiconductor diode


34/40

for an AC input acts like1. Unidirectional switch2. Bidirectional switch3. Cuts off AC part4. Power booster

15. Reverse saturation current inP-N junction diode is due to

1. Hole conduction2. Electron conduction3. Minority carrier conduction4. Majority carrier conduction

16. In the zener diode the breakdown in the reverse characteristiccurrent is due to

1. Electrons2. Hole

3. Electron hole pair4. Crystal ions

17. The percentage of voltageregulation is defined as

1. V no load " V load r100 /V load

2. V load " V noload r100 / V load

3. V load " V noload r100 / V no load

4. V no load r100 / V load18. Filtering is effected by shuntingthe load with a

1. Capacitor2. Resistor3. Inductor4. None of these

19. Without applying the biasingvoltage the transistor current wouldbe

1. Maximum

2. Minimum3. No change4. Zero

20. In the transistor the doping atthe emitter is much larger than thebase results in

1. Emitter current entirely ofholes

2. Emitter current entirely ofelectrons

3. Base current is due toelectron-hole pair

4. Emitter does contribute

carrier which can reach collector21. The largest current carrying

component in P-N-P transistor is1. Electrons2. Holes

3. Electron hole pair4. Silicon atoms

22. The circuit shown in the figurerepresents

1. Rectifier2. Clamping circuit3. Clipping circuit4. Low pass filter

23. Clamping circuit is used for1. AC to DC conversion

2. Biasing3. Limiting the amplitude4. Wave shaping

24. For ideal clipping circuit oneshould use a diode with cut-involtage

1. 0.7V b.1.1V c.0V d. 0.2V25. The ratio of peak inverse

voltage of full wave and half wave

rectifier is1. 1 b. 2 c.1/2 d. 1/426. Which of the following

transistor configuration is a poweramplifier

1. Common emitter2. Common base3. Common collector4. All of the above

27. In a active mode of a

transistor, collector conductiontakes place due to

1. Majority carrier2. Minority carrier3. Common collector4. All of the above

28. Common emitter configurationis used for a

1. Current amplification2. Voltage amplification3. Current and voltage

amplification4. Charge amplification


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29. The transistor configurationwhere input is emitter and output iscollector is called:

1. Common emitter2. Common base common

collector3. Voltage follower(current

gain)30. Beta of a transistor is given by

1. Ib/Ic b. Ic/Ib c.Ib/Ie d. Ic/Ie31. Germanium transistor is

preferred over silicon transistor inthe following application

1. High frequency2. High power

3. Low voltage4. Power rectification

32. SCR is based on the principle of1. Voltage regeneration2. Current regeneration3. Power regeneration4. Power rectification

33. The number of clock pulsesarriving at the digital counter input,should be in the form of

1. Decimal2. Binary3. Octal4. Hexadecimal

34. In which of the counter theclock input is common to all flipflops

1. Asynchronous counter2. Synchronous counter3. Decade counter4. Down counter

35. Multiplexer helps in which ofthe following

1. Repetition of similar circuitconstruction

2. Selecting all the signal atthe output at the same time

3. Prevention of constructingsimilar circuits

4. Increase in theconstructional costs due torepetition circuits36. Full adder for two inputs can be

developed with the help of

1. Two half adder on OR gate2. One half adder and two OR

gate3. An EXOR gate and AND gate4. Two AND gates and an OR

gate37. The important use of gray code

is for a1. Ripple counter2. Full adder3. Encoder4. Decoder

38. In which of the code only onebit changes at each time

1. BCD2. Aiken code

3. Excess 3 code4. Gray code

39. In Johnson code for N bits, themaximum number can be formed isgiven by an expression

1. 2.N b. 2N c. 2N "2N d. None of these40. The active mode of transistor

operation is used in log circuitsbecause of its

1. Non linearity2. Linearity3. Switching nature4. High speed

41. Intermediate frequency intelevision receiver is

1. 26-46 MHz2. 1.6-2.3 MHz3. 455-KHz4. None of these

42. At absolute temperature, a

silicon crystal acts like an insulatorbecause

1. Electrons cannot movethrough a crystal

2. Electrons are tightly held byother atoms

3. Electrons can break awayonly by supplying energy

4. All of the above43. Extrinsic semiconductor is

1. Doped with impurities2. Exists in the pure state3. N-type only


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4. Only P-type44. The process of extracting the

audio information from themodulated envelope is called

1. Modulation

2. Detection3. Transmission4. Oscillation

45. Selectivity of a radio receiver isdefined as

1. Ability to reproduce theoriginal frequencies

2. Ability to eliminate wantedfrequencies

3. Ability to reject unwantedfrequencies

4. Ability to pick up the weaksignal46. Digital counter cannot be used

as1. Clock2. Timer3. Event counter4. Multiplier

47. Distortion in the amplifier isdue to

1. Non linearity of the device2. Inductance presents in thecircuits

3. Capacitance4. Stray effect

48. The purpose of RF amplifiertuning in the radio receiver is

1. To reject all the frequencies2. To select all the frequencies3. Only to select required

frequencies & amplification

4. To vary the band width49. The intermediate frequency

used in the radio receiver is1. 455KHz b. 1.6

MHz c. 20 MHz d. 60 MHz50. The purpose of using tuned

circuit between stages in the radioreceiver is

1. To increase the selectivity2. To increase the sensitivity3. To increase both selectivity

and sensitivity4. To get the detector output

51. In an amplifier, the frequencycharacteristic may be divided intohow many regions

1. Two b. Three c.Four d. Zero

52. Op.amp. has high inputimpedance because

1. High band width2. Differential amplifier3. Current source at input end4. Common collector

configuration53. Gain of an OP amp. In inverting

mode is "Rf / Rn provided, theOP.amp. has

1. Low output impedance

2. Low input bias current3. High CMRR4. High open loop gain

54. Slew rate of an OP.amp.is1. Change of O/p voltage with

time2. Propagation speed3. Input RC time constant4. Off set voltage drift

55. Instrumentation OP.amp. is

used in application where1. Two instrument are to beinterfaced

2. Input is very low level signal3. DC signals are involved4. Differential signals are

involved56. An OP.amp. integrater will be

1. Capacitor at input2. Diode at input3. Diode feed back

4. Capacitor feed back57. A logarithmic amplifier will

have1. Inductor feed back2. Diode feed back3. Resistance feed back4. Thermistor feed back

58. OP.amp. can be converted intocapacitor by

1. Increasing bandwidth2. Removing feed back3. Increasing input impedance4. Positive feed back


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59. Comparators are used as1. Switching device2. Linear amplifiers3. Power amplifiers4. High speed amplifiers

60. Typical output impedance of741 OP amps. is

1. 0.5 W b. 1 K W c. 1W d. 75 W61. Typical unity gain bandwidth of

741 OP amps. is1. 10 MHz b. 100

KHz c. 1 MHz d. 1.5 MHz62. OP.amp. wein bridge oscillator

works when the over all gain is1. 180 b. 3 c.

1.2 d. 12563. Important part in a electronic

voltage regulator is1. Error amplifier2. External pass transistor3. Reference voltage diode4. All the above

64. To generate a triangular waveform from a square wave

1. Differentiator is used

2. Integrator is used3. Logarithmic amplifier isused

4. Clipping circuit is used65. For multiplying two analog

signals which one of the following isused

1. Comparator2. Hall effect device3. Gunn diode4. Tunnel diode

66. Which of the following device isused as an electronic memoryelement

1. Astable multivibrator2. Monostable multivibrator3. Magnetic tape4. None of these

67. Phase sensitive detector inlock-in-amplifier is used

1. To increase the sensitivity ofan instrument

2. To limit the bandwidth3. To increase the dynamic

range of the signal4. To increase the input

impedance68. In television transmission

video signal is

1. Frequency modulated2. Amplitude modulated3. Phase modulated4. delta modulated

69. The Boolean function XYZ + YZ+ XZ, after simplification gives

1. X b. Y c.Z d. X+Y+Z70. Extremely low power

dissipation and low cost per gatecan be achieved in

1. MOS ICs2. CMOS ICs3. TTL ICs4. ECL ICs

71. Which of the following digitalIC families can give maximum fan-out

1. ECL b. PMOS c.HTL d. CMOS72. A punched card has

1. 22 rows, 90 columns2. 12 rows, 80 columns3. 12 rows, 2 columns4. 8 rows, 128 columns

73. Which one of the following is a16 bit microprocessor

1. Zilog 802. Intel 80853. Motorola 68004. Intel 8086

74. (0.3125)10 when converted

to base 8 gives1. (0.16)8 b.

(0.26)8 c. (0.24)8 d.(0.124)875. Excess " 3 code is a

1. Weighted code2. Cyclic code3. Error correcting code4. Self complementing code

76. ASC II code is a1. Error detecting code2. Self correcting code3. An alphanumeric code


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4. A weighted code77. Modulo " 2 addition is

represented by1. f = XY + XY2. f = XY + XY

3. f = X + XY4. f = XY + XZ + YZ

78. Which one of the followingBoolean identities is correct?

1. XYZ + YZ + XZ = YZ + XZ2. XYZ + YZ +XZ = XY + XZ3. XY +XZ = XY + XZ + YZ4. X + XY = XY

79. SN7410 IC is a1. Quad 2 input NAND gate2. Triple 3 input NAND gate

3. Dual M/S J-K flip flop4. None of these

80. Intel 8085 microprocessor hastwo registers known as primary datapointers these are

1. Registers V & C2. Registers D & E3. Registers H & L4. None of these

81. Intel 8080 microprocessor has

an instruction set of 91 instructions.The op-code to implement theinstruction set should be at least

1. 6 bit b. 7 bytes c.7 bit d. 8 bit82. A micro programmed computer

can have the following memories inits control memory unit

1. Semiconductor ROM2. Semiconductor RAM3. Magnetic RAM

4. None of these83. In digital circuits parallel

operation is preferred because1. It requires less memory2. Circuitry is simple3. It is faster than series

operation4. For None of these of the

above reasons84. SN 7401 IC is a

1. Quad 2 input NAND gate2. Quad 2 input NAND gate

with open collector output

3. Quad single input NANDgate with open collector output

4. None of these85. What is the binary code of

(26)?

1. 11001 b.10001 c. 11010 d.1010086. The basic RS flip flops is

1. A bistable multivibrator2. A monostable multivibrator3. An astable multivibrator4. None of these

87. The input impedance of anoperational amplifier is

1. Very small

2. Zero3. Very high but not infinite4. Infinite

88. Sn 7411 is1. OP.amp. monolithic and

short circuit protection in-built2. Two input NAND gate3. Three input NAND gate with

open collector output4. None of these

89. The output voltage of anoperational amplifier is1. 90 deg out of phase from

the input2. 90 deg out of phase from

the input3. 45 deg out of phase from

the input4. 180deg out of phase from

the input90. The equivalent octal number of

(492) is1. 574 b. 547 c.

754 d. 75891. The equivalent decimal number

for gray code 1011 is1. 14 b.

13 c. 41 d. 3192. The output will be only if all

inputs go to 1 in case of1. OR gate b. AND

gate c. NAND gate d. NOTgate93. Which of the following circuits


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is known as half adder?1. AND circuit2. OR circuit3. Exclusive OR circuit4. None of these

94. Which of the followingmemories is used to store variablequantities of the data?

1. RAM b. ROM c.PROM d. EPROM95. Large scale Integrated (LSI)

circuits usually contain1. Less than 10 gates2. 10 to 100 gates3. more than 100 gates4. more than 1000 gates

96. The Boolean expression A + AB+ B on simplification can bereduced to:

1. 0 b. 1 c. A + B d.A + B97. For realizing a decade counter

using flip-flops the minimumnumber of flip-flops required is

1. 4 b. 5 c.6 d. 10

98. Which logic family is widelyused in SSI & MSI applications?

1. ECL b. DTL c.TTL d. None of these99. An amplitude modulation

detector detects1. The peak value of the

modulation signal2. The envelop of the

modulation signal3. The peak value of the carrier

signal4. The average value of the

carrier signal100. Microwave (MW) links aregenerally preferred to coaxial cablefor TV transmission because:

1. They have less overall phase

distortion2. They are cheaper3. Of their greater bandwidth4. Of their relative immunity to

impulse noise.

Answer

1. b

2. c

3. d

4. d

5. a

6. a

7. a

8. a

9. b

10. c

11. b

12. b

13. c

14. a

15. c

16. c

17. a

18. a

19. b

20. b

21. b

22. b

23. c

24. b

25. a

26. d

27. a

28. c

29. b

30. b

31. b

32. c

33. b

34. b

35. a

36. a

37. c

38. d

39. b

40. a

41. d


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42. d

43. a

44. b

45. c

46. d

47. a

48. c

49. a

50. c

51. c

52. b

53. d

54. b

55. b

56. d

57. d

58. a

59. a

60. a

61. a

62. b

63. d

64. b

65. a

67. b

68. b

69. c

70. b

71. d

72. b

73. d

74. c

75. d

76. c

77. a

78. c

79. b

80. c

81. c

82. a

83. b

84. b

85. c

86. a

87. c

88. c

89. d

90. c

92. b

93. c

94. a

95. c

96. b

97. a

98. c99. b

100. A

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