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ELECTRONICS & TELECOMMUNICATION ENGINEERING

IES PAPER-I (2001)b. 30n and SQc. ISO and 30nd. 200 and 350Fo r the circuit shown in the given. figure,when the switch is at pesitlen A ., thecurrent i(t) = Isin (rot + 300) A. Whenswitehss moved to position B at rime t =0,the power dissipated at the switchinginstant in the resistor R remains-unchanged

. { f a : ; . Q $1.

Which one of the following parametersdoes. not exist fo r the two-port networkshown in the given figure?a . ABeDh. yc. hd. Z2 .

z-matrix for the network shown In thegiven f igur e isa. [2S+ 1 2S3 ]2 . 1 " 2 s+- s

-28 j328+-sc. [ 2 . 1 ' + I +25 1

-2s 2 .1 '+3/ s

d. [2S+~ -2s 12s 2 2 s +3/ s

3.

Fo r the equivalent )..".1 circuit shown in thegiven figure, the values of R.O\B and R rw arcrespectivelya . SO and Isn

4.

The value of I and th e element X wouldrespectively, Dea . 1 A and resistorh. 2 A and capacitorc. 3 . A and resistord. 4 A and capacitor

5.

~,."~"L~6.

In the circuit shown in the given figure, thevalues of i (O+) and l(co) will be,respectivelyIn the circuit shown ill the given figure,C 1 =C 2 = 2 F and the capacitor C 1 has avoltage of20 V when S is open.

~Irf' C ' I 1 :It the switch S is closed at t =0 the voltageVc will be aa > Fixed voltage of 20 Vb. fixed voltage 0 f l 0 Vc. fixed voltage of -10 V

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E N G I N E E R S I N S T I T U T E O F I N D I Ad . sinu so id al v olta geThe circuit shown in the given figure is inthe steady sta te w ith the sw itch S closed

20

2b. a high-pass filterc. an a ll - p as s filte rd, a ba nd - pa ss filter

12. ' If a function J ( t ) u ( t ) is shifted to rig htside by to , then the fuH CfiQn can beexpressed a sa. J ( t - t o ) u ( t )b. J { t ) u ( t - t ( ) )c. J ( t - t o ) u (t- t G Jd. f ( t + t g ) u ( t + t Q )The dual of a pa ra llel R - C cirouit is aa . geri:es R - C circlrit

13.

14 :

b. Series R_~ Lcireaitc, Pa ra llel R - Ccireuitd. Pa ra llel R - Lcircuit. . . S ( S 1 + I )'ID n v tQ g p pm t Impedance Z ( s ) = 0 4s : +

20

is n : @ t realizable b ec au se th ea . num ber of z eros is more 'than the

number o f p ole sb. poles a nd z eros lie on the imaginary

aXISc .. poles and zeros do not alternate on.. .nnagmary ax!d. poles and zer s a re no t located on th e

rea l a xis15 , The f un ct io n s + 2 + ~ c an b e re aliz e ds

16 ,

a . both as a driving point im pedance anda s a driving point admi t tance

h. a s an im pedance, bu t no t a s anadmi t tance

c. a s an adm ittance, but not a s animpedance neither

d. as an impedance nor a s a n a dm i tta nc e?s+5 .

If F { s ) = = = , - ' . , then f ( l ) IS givens: + 5s + 6b ya. e -c.s. [cosh 0 . 5 1 + sinh 0 . 5 f ]b. e:" [cosh 0.5 t + sinh 0.5 /]c. J 2 e " c . 5 1 sin(O.5t+4SO)d. e:" {cosO.5l+sinO.5t}If R , L. C and G are th e resistance,inductance, ca pa cita nce a nd conductanceo r a tra nsm ission line respectively, then

~ ~_l_H _ J T t FThe current 1 (t) a fter S is opened a t t= 0 is

8 .

a. a dec rea sing exponen ti alb. an increasing exponentialc. a d amp e d s in us oidd. oscillatoryA resistor R of 1 Q and two inductors Lland L 2 of inductances 1B and 2H ,respectively, are connected i n p a ra lle l. Atsom e tim e, the currents through LIand L 2are IA and 2A , respectively. Th e currentthrough R at t ime t=w ill be

17.

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a. zerob. lAc. 2Ad. 3AA u nit s te p c urr en t is a pp lie d to a netwcrkconsisting of only passive elem ents. Thevoltage across the current seurce observedis v( t) :: : (1 + e- t!}T he s im p le st p ossib lenetwork will consist of the e l e m e n t sa . 1 resistor a nd 2 c apa cito rsb. 1 resistor and 2 ii1ductorsc. 2 r es is to rs a nd r capacitord. 2 resistors and 1 inductor.

10. If the numerator of a second -order transferfunctionF(s)a consta nt, then the filter is a

9 .

isa . band - p a ss f il te rb, band - stop filterc. high - pa ss f il te rd. low - pass filter11 .

The pole-z ero pa tterns shown in the givenfigure is fora . a low - pass filter

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E N G I N E E R S I N S T I T U T E O F I N D I A

18.

the condition for distortion lesstransmission line isa. RlC=GLLh. RC=LGc. R2C= 02Ld. RC:l= OL

2

18. The energy stored per unit volume inan electric field (with usual notations) ISgiven bya. 1 /2 SH2b. 1I2 sEc. 1 /2 SE2d. EE2A positive charge of Q coulombs is locatedat point A(O, 0, 3) and, a negative chargeof magnitude Q coulombs is located atpoint B(O, 0, 3). The electric fieldintensity at point C(4 , 0., 0) is in the3. negative x-directionb. negative z-directionc. positive x-directiond. positive z-direction

19.

20. v= 12 ( r 8 V )+ _ ! _ (2 ! V )+ 8 ' 2 V = 0r c r c r , r:' a7' az l

, . O lV a~ v a 2vh. ~lV= __ +_-+--.. oxJ 0t~ 8z~G. \:v~p

....1 Io ( r ! 6 V i l r t . (.IiTI.d ; . . . . : - - --)+---1Slrl"riir o r l "sinODO, I '; () . .I r : V+ -.-.- --. - 0r'sin o tV)

Gauss law relates the electric fieldintensity E with the volume chargedensity p at a p oint as_...a. vxR=snP

2 5 .

b. \l.E = 8'oPc. \I x 1 ; = pi fl'ld. 'VeE -=;" ,p!E:,The input rirnpedance of i..g Inng short-circuited section of a Jossless transmissionline is

26.

a. zerob. inductivec. capacmvcd. infiniteMatch List I (Parameters) with List II(Values) for a transmission line with aseries impedance Z = R + j c t } 1 . n:'rn and ashunt admittance Y = G + jC'l C mho/rn.and select the correct answer:List IA. Characteristic impedance LoB . Propaga tion constant yC. The sending-end input impedance Zu

when the line is terminated III itscharacteristic impedance Z"

list 11I. ,fX Y

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E N G I N E E R S I N S T I T U T E O F I N D I A

C1322

A boundary separates two magneticmaterials of permeability 1 - 1 1 and f J . 2 . Themagnetic field vector in 1 - 1 1 is HI with anormal component HUl and tangentialcomponent Ht, while that in 1 - 1 2 is H 2 witha normal component Hn2, and a tangentialcomponent Ht2. Then the derivedconditions would bea . HI =H~ and H,,= H"b. H = Hand f1 H = If .H'1 2 .] III 1"""'2 n~

2. .jZ/Y3. .jY/ZCodes;

A Ba . 3 Ib. 2 3c. 2 1d. 1 2

2 7,

32 . .

d .For frequencies up to 16~Otransmitting antenna used is aa. Parabolic dishb. Vertical antennac. Yagi antennad. Turnstile antennaThe radiation field of an antenna at adistance r varies as3. Ill'b. 1Ir2c. l/ r 3d. llr4The wave radiate by a helicalantenna isa. Linearly polarizedh. 'Right circularly polarizedc. Lefbeircularly polarized(L Elliptically polarizedWbich one of the following IS NOT acorrect Maxwell equation?

~ aD -a. Vxil=-+Ja t- aHb. \lxE=~' ~a l

28.

29.

30.

31.

c. V.D =Pd. VB =0

4In a certain micro strip path antenna, theunexcited patch is of length L, width W,thickness of the substrate being h and itsrelative permittrvrty e, Then, thecapacitance of the unexoft~~.'b~atch isa . LW/ shb. LW / oc,hc. E : LW I hrd. f :o &/ ,LW I hMatch List I (Msxwell equa:tiion9 witih ListII (Description) and select the correctanswenList IA. c f i d Z i = 0B 4 D da =1pd'Vc. c f1 .d ~ =-qB.daD. ~.H.d; =4 (D + J ) .datistU1. The mmf around a closed path is equal

to the- conduction current plus the timederivsnve of the electric displacementcurrent through any surface boundedby the patm.

2. The emf around a closed path is equalto the time derivative of the magnetic

---'------'''J-Jisplacement through any surfacebounded by the path

3. TIle total electric displacement throughthe surface enclosing a volume is equalto the total charge within the volume

4. The net magnetic flux emergingthrough any closed surface is zero

Codes;ABC D

4

33.

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

34. In a uniform plane waveI E I / I H I isa. ~p/&b. ~E/ j. 1c. Id. j;;

14the value of

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E N G I N E E R S I N S T I T U T E O F I N D I A35. For a hollow waveguide, the axial current

must necessarily bea. a combination of conduction and

displacement currentsb. conduction current onlyc. time - varying conduction current anddisplacement currentd. displacement current onlyA cylindrical cavity resonates at 9 GHz inthe Till mode. The bandwidth 3 dB ismeasured to be 2.4 MHz. The Q of thecavity at 9 GHz isa. 9000/2.4J3b. 9000/2.4 J2c. 9000 x 2.4 J3/.J2d. 9000/2.4The phenomenon of microwave signalsfollowing the curvature of earth is knownas

36.

37.

38.

a. Faraday effectb. ductingc. wave tiItd. troposcatterA. radio communication fink is to beestablished via the ionosphere. The virtualheight at the mid-point elf the path is 300krn and the critical frequency is 9 MHz.The maximum usable frequency Io,r thelink between the stations of distance 800km assuming flat earth. isd. 11.25 MHzb. 12 MHzc. 15l\1Hzd . 25.5 MHzWhich one of the following statements isNOT correct for a plane wave withif ::::::.5e-1)I., cos (106{- 2x) G o A / ma. The wave frequency is 106 r.p.s.b. The wavelength is 3.14 mc. The wave travels along -l- x-directiond. The Wave is polarized in the z-

directionA coil. of resistance of 5 Q and inductance0.4 H is connected to a S O V d.c. supply.The energy stored in the field is

39.

40.

< . I . 10 Joulesb. 20 _joulesc. 40 _lou lcs

4L

42.

43.

44.

45.

46.

5d. 80joulesThe resistivity of the wire material can beexpressed in terms of LMTI system ofdimensional parameter asa. A 1 L " t:r"b. ML2r'rc. /vfL3T-3r"d. /IIiLorc r'A 0 - 150 V voltmeter has an accuracy of1% of full-scale reading, The voltagemeasured by the instrumeritis 7S v. Thelimiting error is3. 1%b. 2%c. 2.5%d. 3%Which one of the following is the bestdefinition of accuracy?a. It is the measure of consistency or

reproducibility of measurementsb. it is the ratio of the change in output

signal to the change in input signalc. It is the -smallest change in measurable

inpntd. It is the closeness with which an

instrumerit reading approaches the truevalue of t]le quantity being measured

\~(hilc measuring the phase differenc ebetween the signals VI(t) = 10 sin i t andv= ( t) = I(}in (cot + ~), the Lissajouspattern observed on eRO was a circle. Thevalue of ~ is

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E N G I N E E R S I N S T I T U T E O F I N D I A

49.

~~~~~~~~dmvThe reading of high impedance voltmeterV in the bridge circuit shown in the givenfigure isa. zerob. 3.33 Vc. 4.20 Vd, 6.66 V

47. Digital measuring instruments use thefollowing three types of A to D convertersr Dual Slope Type2. Counter Type3. Flash TypeThe correct sequence forthe~e convertersin decreasing order of their speed (fastestto slowest) is< . I . 3, 1,2b. I, 2, 3e. 2. 3, 1d. 3, ') 1

48. Consider the following statcmenlsregarding the advantages ef, Andersonbridge:1. It is th e modification of the Maxwell's

inductance-capacitance bridge.2. For measuring the low Q of coils, it is

superior to th e Maxwell's bridge.3. It is simple compared to Maxwell's

bridge.4 . H can be used to determine mutua l

inductance alsoWhich of these statements are correct?a. 1,2 and 3b. 1, 2 and 4c. 2 and 4d. 1,3 and 4Match List I (Bridges) with List JI(Quantities) and select (he correct answerList IA. Maxwell s bridgeB. '0./ icn bridgeC Hays bridge

6D. Schering bridgeList n1. Frequency2, Inductance with value ofQ

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E N G I N E E R S I N S T I T U T E O F I N D I AD. DiaphragmList II1. Pressure2. Torque3. Displacement4. TemperatureCodes;

A B C 0a. 2 4 3 1b. 3 2 4c. 2 1 3 4d. 3 4 2

53. Gauge factor of a strain gauge is definedas the ratio of a per unit change in thea. conductivity to the per unit change in

applied force acting on the elementb. resistance to the per unit change in the

length of the elementc. stress to the per unitdiange in stnlin of

the elementd. current to the per unit change in the

length of the elementA variable reluctance type tachometer has60 rotor teeth, the records 3600counts/minutes. The device speed isa. 60 r.p.s.

54.

b. 1800 r.p.s.c. 3600 r.p.s.d. 7200 r.p.s.

55. Hot wire anemometer is a device used tomeasure the

56.

a. pressure 10 gasesb. liquid dischargec. gas velocitiesd. temperatureConsider the following devices1. Anemometer2. Stroboscope3. AccelerometerThe correct sequence of these devices tomeasure the rotational speed, vibration andairflow, respectively is,a . 2, 3 and 1b. 2, 1 and 3c. 1,3 and 2d. 3,2 and]The pH value of a solution is defined asa. - log (He on concentration)b. log (H' ion concentration)

57.

7

58.c. - log" / (011ion concentration)d. -log (011ion concentration)The piezoelectric crystal voltagesensitivity is defined as aa. voltage developed per U : J 1 1 t stressb. field developed perunftstressc. voltage developOOperunit forced. field developed'perunitfcrceThe bandwidth of an n.bit binary codedrCM signal for an original signalbandwidth of B Hz'isa . BHzb. nB Hz

Bc.~Rznd. n2BHzFor an AM wave, the maximum voltagewa s found to be 10 V and the minimumyo1tas:e was found to be 5 V. Themodulation index of the wave would be

59.

60.

a . 0.33b. 0.52c. 0040d. I D . l

67

The FM telemetry as compared with AMte1emetitYrequires a channel that isa. equal to that of AM telemetryb. smaller than what is. required for AM

telemetryc. 100 times of. that required for AM

telemetryO. 10 times of that required for AM

telemetryAs the Fermi energy of silver is 8.8 x 10-1 9joule, the velocity of the fastest electron insilver at 0 K (Given: Rest mass of electron= 9.1 x 10.3 1 kg) isa. 3.33 x lO 5 rnIsb. 1.39 x 106 m /sc. 4.40 x 107 m/sd. 3xl0~rnIsA four-point probe method is used toevaluate the sheet resistance of asemiconductor epitaxial layer. If a probecurrent of 10 mA produces a voltage dropof 0.22 V between the inner probes, then.the sheet resistance of the layer isa 100 D./squareb. :2] 5 D./square

63.

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E N G I N E E R S I N S T I T I J T E O F I N D I Ac. 572 Q/squared. 1000 Q/square

64. For which of the followingsemiconductors, resistance does not followOhm's law over some specific range of theapplied voltage?1. Germanium2. Gallium arsenide3. Iridium phosphideSelect the correct answer using the codesgiven below:a. 1,2 and 3b .. 1 and 2c. 2 and 3d. 1 and 3Electron mobility and life-time In asemiconductor at room temperature arerespectively 0.36 m2 /(V s) and 340 I - L S . Thediffusion length isa. 3.13 mmb. 1.77 m mc. 3.55 mmd. 3.13 emA piezoelectric crystal pas Young'smodulus of 130 OPa. 'F.he UNiaxial stressthat must be applied to increase itspolarization from 550 to; 555 C m2 is,nearlya. 2.798 GPab. 2.175 GPac. ] .593 OPad. 1.1820Pa

67. The outermost electronic configuration ofa cobalt atom is 3d24s1 Its magnetic

65.

66.

6S.

moment isa. 9 Bohr magnetonsb. 7 Bohr magnetonsc. 5 Bohr magnetonsd. 3 Bohr magnetonsMatch list 1 with List II and select thecorrect answerList I (Applications)A. Permanent magnetsB. High frequency (MHz) applicationsC. ElectromagnetsD. Very high frequency(GHz)applicationsList II (Magnetic materials)1. Ferrites2. Hard magnetic material

83. Garnets4. Soft magnetic materialsCodes;

A B C Da. 1 2 4 3b. 2 1 3 4c. 2 1 4 3d. 2 3 4

69. Match list Iwith list IIand select thecorrect answer:A. Ferro-magnetismB. SemiconductorC. OptIcal property of solid. I D , Sl!p.eIeonductivityUstIL1. d,c. electrical-resistivity vanishes at the

critical temperature Tc2. Doping with impurity increases the

electrical conductivity3. An intemal molecular field BI\I which

I S proportianal to magnetization Mexists at each dipole ar "igns itparallel to other dipoles

4. Above the Neel temperature thedipoles beceme randomly oriented

5 " The conductivity of crystallinesemiconduetors and dielectricsincreased bv radiation incident

C0dc,S,;A B C D

a. 3 5 : 2 Ib. 3 2 5c. 4 5 2 3d. 4 2 5 3

70. Consider the following statements:The dielectric constant of an insulatordepends onI. applied voltage2. frequency of the alternating field

applied.3. temperature4. maximum current density in insulator.Select the correct answer using the codesgiven below:a. 1 and 2b. 1 and 3c. 2 and 3d. 3 and 4

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E N G I N E E R S I N S T I T U T E O F I N D I A71. Which of the following statements are

correct for ceramic materials?1. They are inorganic substances.2 . They are brittle.3. They are good thermal insulators.Select the correct answer using the codesgiven below:a. 1,2 and 3b. 1 and 2c. 2 and 3d. I and 3Laser emission from Ruby crystal isbecause 0f transi tiona, from conduction band to valence bandAb03

b. from conduction band to one of thelevels due to Cr ionsc. between energy levels introduced byCr ions

d. between one of the levels due to Gr ionand valence band of Ab03

Wire-wound resistances are used onlywhena. Precision is essentialb. low values are requiredc. high power rating is necessaryd. costly equipments are manufacturedConsider the following statements:In a transformer, the core material shouldhave low1. coercivity2 .. retentivity3 .. permeabilityWhich of these statements are correct?

72.

73.

74.

a. 1 and 2b. Land 3c. 1 and 3d. 1,2 and 375. Consider the following statements:Impurity diffusion is used insemiconductor to control the conductivity.The nature of the impurity profile shouldhe such that the1. Impurity concentration decreases with

diffusion depth.2. Profile results in an internal electric

field.

9

76.

3. Impurity concentration ishomogeneous with no internal electricfield.

4. Which of these statements are correct?a. 1,2 and 3b. 1 and 3c. 2 and 3d. 1 and2An one - sided abrup:rjtiheticJp. has lQ21perm3 of dopants on the lightly doped side,zero bias voltage and a buitt- in potentialof 0.2 V. The depletion width ofthe abrupt. tio: (taki 1 6 X lrrf9 C - 16unc Ion aJ:ldngq = . ,..:1) .. , 1:0 - ..and EO ~ 8.875 x 1O,n F7m) isa. O.036nmh.O.6I1mc, 3!.lmd. 1.5 rnmWhich of the following statements relateto the Hall effect?r. A potentIa1 difference is developed

across a current-carrying metal stripwhen the strip is placed in a transversemagnetic field.

2, The Hall elect is very weak in metalsbut is large in semiconductors.

.3. The Hall effect is very weak insemiconductors but is large in metals.1 : 1 . it is applied in the measurement of themagnetic field intensity.

a. 1. 2 and 3b. 2 and 4c. 1,3 and 4d. 1,2 and 4The output current Versus input voltagetransfer characteristic of an n-channelJFET is such that there isa. zero current flow t zero input voltage

biasb. current flow only when a positive input

threshold voltage is crossedc. current flow only when a negative

input cut-off voltage bias is crossedd. no cut-off input voltageAn. SCR triggered by a current pulsethrough its gate can be turned off bya. giving another pulse of the same

polarity to the. gateb. by giying pulse to the cathodec. by giving pulse to the anode

77.

78.

79.

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E N G I N E E R S I N S T I T U T E O F I N D I A

80.

d. by reversing the polarity of anode andcathode voltage

Inan MOS transistor, the gate source inputimpedance is1 . lower than the input impedance of a

BJT2. higher than the input impedance of a

BIT3. lower than the input impedance of a

IFET4. higher than the input impedance of a

JFETa. 1 aloneb. 2 and 3c. 4 aloned. 2 and 4At 25C, the collector-emitter voltage dropof a silicon transistor at saturation isapproximatelya. 0.1 V

81.

b. 0. .3 Vc. 0.5 Vd. O.7V

82. The reverse bias breakdown ofhgll speoosilicon transistors is due toa. avalanche breakdown mechanism at

both the junctionsb .. Zener breakdown mechanism at .boththe junctionsc. Zener breakdown mechanism at l:5ase-

collector junction and avalanchebreakdown mechanism at base-emitterjunction

d. Zener breakdown mechanism at base-emitter junction and avalanchebreakdown mechanism at base-collector junction

In the fabrication of a buried layer n-p-ntransistor, the processes involved are1. diffusion2. oxidation3.epi'taxy4. lith(\}grapllyThe correct sequence III which theseprocesses are to be carried out, isa. 2,4,3,1

83.

b. 4,2,1,3c. 2,4, 1,3d. 4,2,3, 1

1084. Match List I (Operating point on the I-V

characteristic) with List II(Devices) andselect the correct answer:List IA 1st quadrantB. 2nd quadrantC. 3rd quadrantD. 4th quadrantList II1. Solar cell2. Photo detector withthigh sens:iti\itty3. Phsto detector with l@w se:rn.sftikvity4 . ~ e(i} 1!H ierdiodeCod.

A c D1. 4

~ 3c. sIi 4

344

22

23 2

j. . .Af'.:sertltm (A): A C IrC U It conta m m greaetanees is said to be in resonance if the,@ltageacross the circuit is in phase withthe current through it.B:easmcn ER ) : At resonance, the powerf{l:e;torof tlie c' rcuir s zero.a. Both A and R are true and R is the

correc explanation of Ab. Both A and R are true but R is NOT--1lle correct explanation of Ac. A is true but R is falsed. A is false but R is trueAssertion (A): Programmes broadcast byradio stations operating in the mediumwave band of 550 to 1650 kHz situated atlong distances in excess of 500 krn cannotbe heard during day-time but may be heardduring night-time.Reason (R): In the night-time, radio wavesreflected from the F -layer suffer negligibleattenuation since D- and E-Iayers areabsent during the night-time.a. Both A and R are true and R is the

correct explanation of Ab. Both A and R are true but R is NOT

the correct explanation of Ac. A is true but. R is falsed. Ais false but R is true

87. Assertion (A): For an end-fire array, thecurrent in successive antennas must lag inphase.

86.

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88.

89.

90.

91.

E N G I N E E R S I N S T I T U T E O F I N D I AReason (R): Radiation of successiveantennas willa. Both A and R are true and R is the

correct explanation of Ab. Both A and R are true but R is NOT

the correct explanation of Ac. A is truebut R is falsed. A is false but R is trueAssertion (A): The radio horizon for spacewave is more than the optical horizon.Reason(R).: The atmosphere has varyingdensitya. Both A and R are true and R is the

correct explanation of Ab. Both A and R are hue but R is NOT

the correct explanation of Ac. A is true but R is falsed. A is false but R is trueAssertion (A).: Any indicating instnsmentshould have a damping torque.Reason (R): Without a damping torque, i'Jilepointer takes more settling time.a. Both A and R are v = andcR is: the

correct explanation of Ab. Both A and Rare tme ,blWR is NOT

the correct explanation of A -c. A is true but R is falsed. A is false but R is trueAssertion (A): Potentiometric typeaccelerometers have higherresolution tllanLVDT accelerometer.Reason (R): The resistance offered to themotion is less inL VDT accelerometersthan in Potentiometric accelerometer.a. Both A and Rare true and R is the

correct explanation of Ab. Both A and R are true but R is NOT

the correct explanation of Ac. A is true but R is false( 1 , . A is faIs but R is trueA~Sel1ion fA): 1n superconducting state,bath. entropy and thermal conductivitydecrease.Reason (R): Superconductivity resultsbasicatlydue to zero atomic vibration ofcrystal 'structure.a. Both A and R are true and R is the

correct explanation of Ab. Both A and R are true but R is NOT

the correct explanation of A

92.

11

93.

c. A is true but R is falsed. A is false but R is trueAssertion (A): Copper as an impurity ingermanium has an ionizseen energy of0.25 eV whereas Boren kls ionizationenergy of 0.01 eV.Reason (R): Copper .is an interstitialimpurity whereas RfallOllis a suhsMllltionalimpurity,a. Both A and R ase tffle and R is the

correct explana.l!ion of Ab. Both A and 1 lt are true bnt R is NOT

the-coaect exp1anation of Ac. A is'true 'fuutR 1 S false.t : i . A 1B flisebut R is weAsser{1en (~~: "Ebesemieenductor deviceslike)3:J{}'lshase a maximum temperature ofQ[l.leraXion"belji!1md which they do nofuaeti O J 1 LRieasln ")'~ Extrinsic, p-type and n-typesfmieemrs. behave as intrinsic beyondthat temperaifure and the effect of doping islost. 'a. Beth A and R are true and R is the

eEl;Tfeetxplanation of Ab. Bo.th A and Rare true but R is NOT

the et}n:ect explanation of Ac. A is t r t r G : but R is falsed. A is false but R is trueFhe discfete time system described by yen)=x(n2) isa. causal, linear and time-varyingh. causal, non-linear and time-varyingc. non-causal, linear and time-invariantd. non-causal, non-linear and time-variantWhich one of the following transferfunctions does correspond to a non-minimum phase system?

94.

95.

sa. s " 2 + 2 s + 1s+1b. -?~~-s: + 2s +1s+1c. S2 +2s-1s-I

96..d. i+ 2s+ 1The signal x(t)=Acos(rv'/+) isa. an energy signalb. a power signal

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E N G I N E E R S I N S T I T U T E O F I N D I A

97.c. an energy as well as a power signald . neither an energy nor a power signalWhich one of the following digital filtersdoes have a linear phase response?a. yen) + yen - 1)=x(n) - x(n - 1)b. yen) =1/6 [3x(n) + 2x(n - 1) + x(n - 2)]c. yen) = 1/6 [x(n) + 2x(n - 1) + 3x(n - 2)]d. y(n) = 1/4 [x(n) + 2x(n - 1) + x(n - 2)]For the system described by X = AXmatch List I (Matrix A) with List II(Position of eigenvalues) and select thecorrect answers:List I

98.

[ - 1 2 ]. o -2[ - 1 - 2 ]. - 2 - 4

C. [ ~ ~ 1 ]D. [ ~ ~]List II1 . One eigenvalue at the origin2. Both the eigenvalues in the LHP3. Both the eigenvalues in RHP4. Both the eigenvalues on the imaginary

axisCodes;

A B C Da. 2 1 3 4b. 2 1 4 3c. 1 2 4 3d . 1 2 3 4

99. For the system dynamics described bydifferential equation y + 3y + 2y = u(t) thetransfer function of the system representedin controllable canonical form IScrsl- AT! B. The matric A would bea. [ ~ 3 ~ 2 ]b. [~:]

c. [ ~ 2 ~ 3 ]d. [~ ~]

100.

12

lO L

If XI ( t) = 2 sin n:t + co s4n: t andx " ( t ) =sin5m +3sin 13m , thena. x, and X :z both are periodicb. xi and X2 both are not periodicC. x, is periodic, but X2 is not periodicd. x, is not periodic, but x- is periodicThe Fourier transform of a double-sidedexponential signal x( t ) =e- b ! ' 1a. is 2b / (b2 + m 2 )

(lif':fi')e-j-tallb. , Z i ? + u P )c. does not existd. exists only when itis single sided102. The Faariertransform ofii(t) isa. l!jroh. J c oc. 1/(1 +jro)d. n:o( c o ) + l/j(O

1113. Match List Ith LIst II and select thecorrect answer;List IA.. e-QS]3,J-s

l+s

List II1. All-pass filter2. Transport delay3. Lag network4. ServomotorCodes;

A B C Da. 4 3 1 2b. ') 1 3 4c. 2 3 1 4d . 4 ] 3 2

104. A linear network has the system function( s + c)

H-c------'----'--------c-( s + a ) ( s + h )The outputs of the network with zeroinitial conditions for .1\\'0 different inputsare tabled as

Input x(t) Output yet)u(t) 2 + De" + Ee-3