Obj 2008 Paper I IES

7/25/2019 Obj 2008 Paper I IES

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PAPER I

1.

In the circuit show above, the switch is openfor a long time and closed at time t = 0. Whatis the current through the switch after theswitch is closed?a. Zerob. 1 Ac. 2 Ad. 5 A

2.

In the circuit shown above, the switch isclosed at t = 0. What is the initial value of thecurrent through the capacitor?a. 0.8 Ab. 1.6 Ac.

2.4 Ad. 3.2 A

3. Consider a circuit which consists of resistorsand independent current sources, and oneindependent voltage source connected betweenthe nodes i, j. The equations are obtained forvoltages of n unknown nodes with respect toone reference node in the form

1

2[ ]

n

V

V

V

=

M

M

M MM

What are the elements of the ?a. All conductancesb. All resistancesc. Mixed conductances and constantsd. Mixed conducances and resistance

4.

In the circuit show above, what is he voltagevab(t)?

a. 1 1dv

vdt

+

b. v1

c. 1 1dv

RCvdt

+

d. 1 1dv

RC vdt

+

5.

In the circuit show above, when is the powerabsorbed by the 4 resistor maximum?a. R = 0

b. R = 2 c. R = 4

d.

R =

6. The line integral of the vector potential Aur

around the boundary of a surface S representswhich one of the following?a. Flux through the surface Sb. Flux density in the surfaces Sc. Magnetic field intensityd. Current density

7. What is the electric flux density ( in C/m2) ata point (6, 4, -5) caused by a uniform surface

charge density of 60 C/m2at a plane x = 8?a. -30 xa

b. -60 xa

c. 30 xa

d. 60 xa

8. An infinitely along straight conductor locatedalong Z-axis carries a current I in the +ve Z-direction. The magnetic field at any point P inthe X-Y plane is in which direction?

I.E.S-(OBJ) 2008

ELECTRONICS AND TELECOMMUNICATION ENGINEERING


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2 of 12a. In the positive Z-directionb. In the negative Z-directionc. In the direction perpendicular to the radial

line OP (in X-Y plane) joining the originO to the point P

d. Along the radial line OP

9. A 5 A current enter a right circular cylinder of

5 cm radius. What is the linear surface currentdensity at the end surface?

a. (50/)A/mb. (100/)A/mc. (1000/)A/md. (2000/)A/m

10. Of two concentric along conducting cylinders,the inner one is kept at a constant positivepotential +V0 and the outer one is grounded.What is the electric field in the space betweenthe cylinders/

a.

Uniform and directed radially outwardsb. Uniform and directed radially inwardsc. Non-uniform and directed radially

outwardsd. Non-uniform and directed parallel to the

axis of the cylinders.

11. In a charge-free space, the Poissons equationresults in which one of the following?a. Continuity equationb. Maxwells equationc. Laplace equation

d.

None of the above

12. Consider the following statements relating tothe microstrip lines:1. There is no radiation loss problem in

microstrip lines.2. Modes on microstrip line are only quasi-

transverse electric and magnetic3. Microstrip line is also called as open strip

line.Which of the statements given above arecorrect?

a.

1, 2 and 3b. 1 and 2 onlyc. 1 and 3 onlyd. 2 and 3 only

13. A lossless transmission line of characteristicimpedance Z0and length 1 < /4 is terminatedat the loaded end by an open circuit. What isits input impedance Zs?

a. Zs= j Z0tan lb. Zs= j Z0cot lc. Zs= -j Z0tan l

d. Zs= -j Z0cot l

14. Consider the following elements associatedwith boundary conditions between two media:1. Normal component of B is continuous at

the surface of discontinuity.2. Normal component of D may or may not

be continuous.

Which of the statements given above is/arecorrect?a. 1 onlyb. 2 onlyc. Both 1 and 2d. Neither 1 nor 2

15. In a LDVT, here are two secondary coilswhich are connected for a single output.Which one of the following is correct?a. The coils are in series and in phase

opposition

b.

The coils are in parallel and in phaseopposition

c. The coils are in series and in the samephase condition

d. The coils are in parallel and in the samephase condition.

16. A resistance strain gauge of gauge factor 2 isused as a transducer element. Neglectingpiezoresistive effect, what is the value ofPoissons ratio?a. 0.5

b.

1c. 1.6d. 2

17. Match List I with List II and select the correctanswer using the code given below the lists:List I(Thermo couple)A. Copper ConstantanB. (Platinum Rhodium) PlatinumC. (Rhodium Indium) IndiumD. Iron-Constantan

List II(Temperature range)1. -2000C to +8500C2. -2000C to +3500C3. 00C to 10000C4. 12000C to 20000CCode:

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


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18. Which one of the following statements is notcorrect?a. Data loggers are usually of digital typesb. A digital voltmeter is essentially and A-D

converterc. A servo-type potentiometric recorder has a

frequency response better than that of a

galvometric recorderd. In digital transducers, there are ergonomic

advantages in presenting digital data.

19. A coil is turned to resonance of 500 kHz witha resonating capacitor of 36 pF. At 250 kHz,the resonance is obtained with resonatingcapacitors of 160 pF. What is the self-capacitance of the coil?a. 2.66 pFb. 5.33 pFc. 8 pF

d.

10.6 pF

20. A compensated probe of a CRO containswhich of the following?1. An amplifier2. R-C network3. Only resistive network4. Only capacitive networkSelect the correct answer using the code givenbelow:Code:a. 1 and 2 only

b.

2 onlyc. 3 onlyd. 4 only

21. The accuracy of a 0.10 mA meter is 2%.Whatis its accuracy while taking a reading of 5mA?

a. 0.5%b. 1%c. 2%d. 4%

22. Match List I with List II and select the correct

answer using the code given below the lists:List I(Term)A. Relative errorB. PrecisionC. CalibrationD. ResolutionList II(Statement)1. The ability of the device to give identical

output when repeat measurements aremade with the same input signal

2. The ratio of difference betweenmeasured value and the true value to thetrue value of the measured

3. The smallest increment in measured thatcan be detected with certainty by theinstrument

4. The process of making adjustments on thescale so that the instrument readings

conform to an accepted standardCode:

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

23. Two capacitances, C1, = 150 2.4 F and C2,= 120 1.5 F are connected in parallel. Whatis the limiting error of the resultantcapacitance C?

a.

0.9 Fb. 1.95 Fc. 3.9 Fd. 4.8 F

24. The expression for mean torque T of anelectrodynamic wattmeter can be expressed asT MaVbZc, where M is mutual inductancebetween fixed and moving coils, V is appliedvoltage and Z is impedance of coil. What arethe value of the constants a, b and c?a. a = 1, b = 2 and c = -2

b.

a = 1, b = 2 and c = -1c. a = 1, b = -2 and c = 2d. a = 2, b = 2 and c = -1

25. If R, L and C are the parameters of a resistor,what is the condition for the resistor to be non-inductive?a. L = CRb. L = CR2c. C = LR2d. C = R/L

26.

What precaution(s) is/are required for absolutemeasurement of current by Rayleigh currentbalance?1. Precision balance of special form must be

used for the accuracy of measurement2. The flexible leads, used for taking current

into the moving coil, must not expertappreciable torque upon the movingsystem

Select the correct answer using the code givenbelow:Code:


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27. In a rectangular waveguidea. TE and TEM waves can exist but TM

waves cannot exist

b.

TM and TEM waves can exist but TEwaves cannot exist

c. TE and TM waves can exist but TEMwaves cannot exist

d. TE, TM and TEM all can exist.

28. Which one has the lowest attenuation in acircular waveguide?a. TM11b. TE11c. TE10d. TE01

29. In a parallel plate waveguide, what is theprincipal wave?a. TEM waveb. T wavec. TM waved. Combination of TE and TM waves having

axial components of both electric andmagnetic fields

30. According to Poynting theorem, the vector

product E Hur uur

is a measure of which one of

the following?a. Stored energy density of the electric fieldb. Stored energy density of the magnetic

fieldc. Power dissipated per unit volumed. Rate of energy flow per unit area

31. If the total input power to an antenna is Wt, theradiated power is Wr and the radiation intensityis , then match List I with List II and selectthe correct answer using the code given belowthe lists:

List IA. Power gainB. Directive gainC. Average power radiatedD. Efficiency of the antennaList II1. Wr/Wt

2. Wr/43. 4/Wt4. 4/WrCode:

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

32. When does the maximum radiation for an end-fire array occur?

a.

Perpendicular to the line of the array onlyb. Along the line of the array onlyc. At 450to the line of the arrayd. Both perpendicular to and along the line of

the array

33. As the aperture area of an antenna increases,its gaina. Increasesb. Decreasesc. Remain steadyd. Behaves unpredictably

34. Which of the following capacitors are madeuse of widely for a capacitance application inmonolithic ICs?1. MOS capacitor2. Collector-Substrate capacitor3. Collector-Base capacitor4. Base-Emitter capacitorSelect the correct answer using the code givenbelow:Code:a. 1 and 2 only

b.

2 and 3 onlyc. 3 and 4 onlyd. 1 and 4 only

35. In a network containing active components,output voltagea. will always be greater than input voltageb. will always be equal to the input voltagec. can be less than or greater than input

voltage onlyd. will be less than, equal to or greater than

input voltage

36. An intrinsic semiconductor is doped lightlywith p-type impurity. It is found that theconductivity actually decreases till a certaindoping level is reached. Why does this occur?a. The mobility of holes decreasesb. The mobility of both electrons and holes

decreasesc. The hole density actually reducesd. Effect of reduction in electrons due to

increase in holes compensates more than


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37. Assuming that the electron mobility inintrinsic silicon is 1500 cm2/Vs at roomtemperature (T=300 K) and the correspondingvolt equivalent of temperature VT= 25.9 mV,what is the approximate value of the electron

diffusion constant?a. 40 cm2/sb. 4 cm2/sc. 400 cm2/sd. 4000 cm2/s

38. The voltage stability with time of referencediodes incorporating Zener diodes iscomparable to that of which of the following?a. Dry cellsb. Nickel-cadmium cellsc. Lead-acid accumulator batteries

d.

Conventional standard cells

39. In a MOSFET, the transfer characteristics canbe used to determine which of the followingdevice parameters?a. Threshold voltage and output resistanceb. Trans-conductance and output resistancec. Threshold voltage and trans-conductanced. Trans-conductance and channel length

modulation parameter

40. Assuming an operating temperature T = 300 K

and corresponding VT = 25 mV, what is thechange in semiconductor silicon diode forwardvoltage VDto produce a 10:1 change in diodecurrent ID, while operating in the forward biasregion (< 25 mA)?a. 60 mVb. 120 mVc. 180 mVd. 240 mV

41. The doping concentration on the n-side of a p-n junction diode is enhanced. Which one of thefollowing will get affected?

a.

Width of the depletion region on n-sideb. Width of the depletion region on p-sidec. Width of the depletion region on both

sidesd. No change in width of depletion regions

42. When a junction diode is used as a half-waverectifier with purely resistive load andsinusoidal input voltage, what is the value ofdiode conduction angle (where i is theignition angle corresponding to the cut-involtage)?

a. b. - ic. - 2id. Slightly greater than

43. In a step-graded p-n junction diode, what is theratio of depletion region penetration depthsinto p and n regions (if the ratio of accentor todonor impurity atoms densities of 1:2)?a. 2 : 1b. 4 : 1c. 1 : 2d. 1 : 4

44. What is the most noticeable effect of a smallincrease in temperature in the common emitterconnected BJT?a. Increase in ICEOb. Increase in output resistancec. Decrease in forward current gain

d.

Increase in forward current gain

45. For a BJT, early voltage VA is 100 V. Incommon emitter configuration , eqiescent VCEis 10 V. what percentage change in quiescentICwould occur, if early voltage VA is made ?a. 10%b. 20%c. 5%d. 0%

46. While using a bipolar junction transistor as an

amplifier, the collector and emitter terminalsgot interchanged mistakenly. Assuming thatthe amplifier and the biasing is suitablyadjusted, the interchange of terminals willresult into which one of the following?a. Zero gainb. Infinite gainc. Reduced gaind. No change in gain at all

47. In n-channel enhancement MOSFET, at afixed drain voltage

a.

the drain current is maximum at zero gatevoltage and it decreases with appliednegative gate voltage

b. the drain current has a finite value at zerogate voltage and it increases or decreaseswith the applied voltage of proper polarity

c. the drain current is zero at zero gatevoltage and it increases with the positiveapplied gate voltage

d. the drain current is zero for negative biasvoltage to gate and it increases as negativegate bias is decreased in magnitude


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48. The data sheet for a certain JFET (JunctionField Effect Transistor) indicates that LDSS(drain to source current with gate shorted) =15 mA and VGS(off) (cut-off value of gate tosource voltage)= -5 V. What is the draincurrent for VGS= -2 V?a. 58.8 mA

b.

29.4 mAc. 9.6 mAd. 5.4 mA

49. What one of the following devices can beturned ON of OFF by applying gate signal?a. CSRb. SCSc. Triacd. UJT

50. Why is silicon dioxide (SiO2) layer used in

ICs?a. To protect the surface of the chip from

external contaminants and to allow forselective formation of the n and p regionsby diffusion

b. Because it facilitates the penetration of thedesired impurity by diffusion

c. To control the concentration of thediffused impurities

d. Because of its high heat conduction

51. Why is the term planner technology forfabrication of devices in ICs used?a.

The variety of manufacturing processes bywhich devices are fabricated, takes placethrough a single plane

b. The aluminum contacts to the collector,base and emitter regions of the transistorsin the ICs are laid in the same plane

c. The collector, base and emitter regions ofthe transistors in ICs are laid in the sameplane

d. The device looks like a thin plane wafer

52. In an optional fibre, the light beam propagates

due to which one of the following?a. Simply reflection of light at a boundary

between two mediab. Refection of light in the mediumc. Total internal reflection at the boundary of

the fibred. Scattering of light in the medium

53. Dispersion in an optical fibre used in acommunication link is of which type?a. Angular dispersionb. Modal dispersion

c. Chromatic dispersiond. Dispersion arising due to structural

irregularities in the fibre.

54. If v-icharacteristic of a circuit is given by v(t)= ti (t)+ 2, the circuit is of which type?a. Linear and time invariantb. Linear and time variant

c.

Non-linear and time invariantd. Non-linear and time variant

55.

Which one of the following represents thelinear mathematical model of the physical

system shown in the above figure?

a.2

2

( ) ( )( ) ( )

d x t dx t m b kx t f t

dt dt + + =

b.2

2

( ) ( )( ) 0

d x t dx t m b kx t

dt dt + + =

c.2

2

( ) ( )( ) ( ) 0


dt dt + + + =

d.2

2

( ) ( )( ) ( ) 0


dt dt + =

56.

If the state space equation of a system is3 1

0 2x x

=

and the initial state value x(0) = [10 0]T, thesteady-state value is [A ]T, what are therespective value of A and B?a. 0, 0b. -3, -2c. 0, 1

d. ,

57.

Which one of the following function is aperiodic one?

a. sin (10 t) + sin (20 t)b. sin (10 t) + sin (20 t)c. sin (10 t) + sin (20 t)d. sin (10 t) + sin (25 t)

58. What is the average power for periodic non-sinusoidal voltage and currents?a. The average power of the fundamental

component alone


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harmonics excluding the fundamentalc. The sum of the average powers of he

sinusoidal components including thefundamental

d. The sum of the root mean square power ofthe sinusoidal components including thefundamental

59. Which one of the following is the correctrelation?

a. F(at) aF(/a)b. F(at) aF(a)c. F(t/a) aF(/a)d. F(at) (1/a) F(/a)

60. The Fourier transform of a function is equal toits two-sided Laplace transform evaluateda. on the real axis of the s-planeb. on a line parallel to the real axis of the s-

planec. on the imaginary axis of the s-planed. on a line parallel to the imaginary axis of

the s-plane

61. For matching of a radio frequency coaxial lineto a purely reactive loada. quarter-wave transformer would work

better than stub matchingb. stub matching would work better than

quarter wave transformerc. both quarter wave transformer and stub

matching techniques would work equallywelld. both quarter-wave transformer and stub

matching techniques would fail

62. If an infinite homogeneous isotropic mediumis modeled as an equivalent transmission line,the characteristic impedance of thecorresponding transmission line is known asitsa. characteristics impedanceb. iterative impedancec. wave impedanced.

intrinsic impedance

63. Match List I with List II with respect to thesynthesis of R-C driving point function Z(s) =1/Y(s) and select the correct answer using thecode give below the lists:List I(Form)A. Foster I formB. Foster Ii formC. Cauer I form

D. Cauer II formList II(Method)1. Continued fraction expansion of Z(s)

around s = 2. Partial fraction expansion of Y(s)/s3. Continued fraction expansion of Z(s

around s = 0

4.

Partial fraction expansion of Z(d)Code:

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

64. The lowest and the highest critical frequenciesof an R-L driving point impedance are,respectivelya. a zero, a pole

b.

a pole, a polec. a zero, a zerod. a pole, a zero

65. For an RC driving point impedance functionZRC(s)

a. ZRC(0) ZRC()b. ZRC(0) = ZRC() onlyc. ZRC(0) ZRC()d. ZRC(0) > ZRC() only

66. Laplace transform of sin (t + )

a.2 2

cos sins

s

++

b.2 2

coss

+

c.2 2

sins

s

+

d.2 2

sin coss

s

++

67. A two port network has z11= 11/35, z12= z21=

2/35, z22= 3/35. Its y11and y12parameter will,respectively, bea. 3, -2b. 3, 2c. 13, -2d. 13, 2

68. A reciprocal two-port network is symmetricalif

a. A = 1b. A = Cc. z11= z22


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69. Inside a waveguide with perfectly conducingwalls, any current present is in the form ofa. displacement current onlyb. conduction current onlyc. partially displacement current and partially

conduction current

d.

sometimes displacement current andsometimes conduction current

70. Which one of the following is a passivetransducer?a. Piezoelectricb. Thermocouplec. Photovoltanic celld. LVDT

71. A 0-250V voltmeter has a guaranteed accuracyof 1% full scale reading (deflection. The

voltage measured by this instrument is 100V.The limiting error is given bea. 1.25%b. 255c. 0.25%d. 2.5%

72. Which one of the following materials is notused as a piezoelectric transducer?a. Rochelle saltb. Lithium sulphatec. Barium titanate

d.

Tungsten oxide

73. Which one of the following modulationtechniques is the most efficient for pulsetelemetry?a. PAMb. PCMc. PDMd. PPM

Direction:

Each of the following seven (7) items consists of two statements,one labeled as Assertion (A) and the other as Reason (R). Youare to examine these two statements carefully and select theanswers to these items using the code given below:

Code:

(a) Both A and R are individually true and R is the correctexplanation of A

(b) Both A and R are individually true but R is not thecorrect explanation of A

(c) A is true but R is false

(d) A is false but R is true

74. Assertion (A): The z-transform of the outputof an ideal samplers is given by

( ) 1 20 2 .... n

n

KK KZ f t K

z z z= + + + +

Reason (R): The relationship is the result ofapplication of z = e-sT, where T stands for thetime gap between the samples.

75. Assertion (A): The Kirchhoffs current lawstates that the sum of currents entering at anynode is equal to the sum of currents leavingthat node.Reason (R): The Kirchhoffs current law isbased on the law of conservation of charge.

76. Assertion (A): In a linear network, thesuperposition theorem can be used to calculatepower dissipation in a resistive branch of thenetwork.Reason (R): Superposition theorem is validfor currents and voltages, and therefore is

valid also for power dissipation.

77. Assertion (A):Power factor is defined as theratio of apparent power to the average powerin an a.c. circuit.Reason (R):The magnitude of power factor isalways less than unity.

78. Assertion (A):Sinusoidal response in an a.c.circuit can be represented in rectangular formas v = Vcos + jVsin , exactly in a waysimilar to vectors which we come across forforce analysis in mechanics.Reason (R):Phasors are nothing but vectors.

79. Assertion (A):A high-pass R-C circuit has alower cut-off frequency but does not have anyupper cut-off frequency.Reason (R):The transfer function of a high-pass R-C circuit can be written as

( )( )12

1

1| | , tan /

1 /H arc f f

f f= =

+

where 11

2

f

RC

=

80. Assertion (A): VTVM gives more accuratereading compared to the accuracy of PMMCtype of indicating instrument used in it, whilemeasuring voltages across high resistances.Reason (R): The electronic circuits used inVTVM make it more accurate by increasing itssensitivity.

81.


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For the circuit shown in the above figure, whatis the natural frequency?a. 1 M rad/sb. 2 M rad/s

c.

3 M rad/sd. 5 M rad/s

82. Which one of the following relations forpower is not correct?

a. P = VIcos b. P = Re part of [VI*]c. P = Re part of [V*I]

d. P = VIsin

83. What is the number of chords of a connectedgraph G of n vertices and e edges?

a.

n(n-1)/2b. n-1c. e-n-1d. e-n+1

84.

What is the appropriate load resistor thatdraws maximum power from the source in thecircuit given above?

a. (5/6) b. (1/3) c. (2/3) d. None of the above

85. Match List I and List II and select the correctanswer using the code given below the lists:List-I(Theorem/Law)A. Nortons theoremB. Superposition theoremC. Thevenins theoremD. Kirchhoffs current lawList II(Property)1. Effect of independent sources in a linear

circuit are additive2. Law of non-accumulation of change holds

good at nodes

3. Current source with shunt resistor4. Voltage source with series resistorCode:

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

86. Which of the following statements areassociated with Thevenins theorem?1. Impedance through which current is

required is removed and open-circuitvoltage is found

2. It is applicable to only d.c. circuits3. The network is replaced by a voltage

source and a series impedance remainsafter removing the load impedance.

Select the correct answer using the code givenbelow:

Code:a. 1 and 2 onlyb. 1 and 3 onlyc. 2 and 3 onlyd. 1, 2 and 3

87. A random variable X is defined by the doubleexponential distribution

Px(x) = ae-bx|x|, - < x <

where a and b are +ve constants. What is therelation between a and b so that px(x) is aprobability density function?

a.

a = b/2b. b = a/2c. a = bd. a = 1/b

88. What is the spectral density of white noise?a. A constant

b. ()c. [()]2d. A step function is

89.

If X(z) is 11

1 z with |z| > 1, then what is thecorresponding x(n)?a. e-nb. enc. u(n)

d. (n)

90. The convolution of f(t) with itself is given to

be ( )0

t

F d . Then what isf(t)?a. The unit ramp function


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10 of 12b. Equal to 1c. The unit step functiond. The unit impulse function

91. Which one of the following is the impulseresponse of the system whose step response isgiven as C(t) = 0-5(1-e-2t)u(t)?a. e-2tu(t)

b.

0.5(t) + e-2tu(t)c. 0.5(t) 0.5 e-2tu(t)d. 0.05e-2tu(t)

92. Match List-I with List-II and select the correctanswer using the code given below the lists:List I[Function in time domain f(t)]

A. ( )0 0sin tu t t ]

B. ( ) ( )0 0 0sin t t t u t t

C.( ) ( )0 0sin

t t u t

D. ( )0sin tu t

List-II[Corresponding Laplace transform F(s)]

1. 02 2

0s

+

2. 002 2

0

t se

s

+

3.0

1 00 02 2

0

sin tant s

et

ss

+

+

4. 1 00 02 20

1sin tant

ss

+

Code:A B C D

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

93. A voltage having the Laplace transform2

24 3 27 6 5

s ss s

+ ++ +

is applied across a 2 H inductor

having zero initial current. What is the currentin the inductor at t = ?a. Zerob. (1/5) Ac. (2/7) Ad. (2/5) A

94. What is the Laplace transform of cos 0t?

a. 02 2

0s

+

b.2 2

0

s

s +

c.( )

2

0s

+

d.( )

2

0

s

s +

95. If f(t) is an even function, then what is itsFourier transform F(j)?

a. ( ) ( )0

cos 2f t t dt

b. ( ) ( )0

2 cosf t t dt

c. ( ) ( )0

2 sinf t t dt

d.

( ) ( )0

sin 2f t t dt

96. If the Fourier transform of f(t) is F(j, thenwhat is the Fourier transform off(-t)?

a. F(j)b. F(-j)c. F(j)d. Complex conjugate of F(j)

97. Epitaxial III-V group semiconductorcompounds have which one of the following

crystal structures?a. BCCb. FCCc. Hexagonald. Zinc blende

98. What is the unit of measurement ofsurface/sheet resistivitya. ohm/metreb. ohm metrec. ohm/sq. metred. ohm

99. An intrinsic semiconductor with energy gap1eV has a carrier concentration N attemperature 200 K. Another intrinsicsemiconductor has the same value of carrierconcentration N at temperature 600 K. What isthe energy gap value for the secondsemiconductor?a. (1/3)eVb. (3/2) eVc. 3 eVd. 9 eV


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100. Consider the following statements :n-type of silicon can be1. formed by adding impurity of phosphorus2. formed a adding impurity of arsenic3. formed by adding impurity of boron4. formed by adding impurity of aluminumWhich of the statements given above are

correct?a. 1 and 3 onlyb. 3 and 4 onlyc. 1 and 2 onlyd. 1, 2, 3 and 4 only

101. Which one of the following materials is not apiezoelectric material?a. BaTiO3b. Quartzc. Rochelle saltd. Yttrium garnet

102. Consider the following statements for thepiezoelectric materials:1. All piezoelectric materials are ferroelectric

materials also2. Piezoelectric materials have high value of

dielectric constantWhich of the statements given below is/arecorrect?a. 1 onlyb. 2 onlyc. Both 1 and 2

d.

Neither 1 nor 2

103. Consider the following statements:An insulating material shows polarization dueto charged atoms. Its polarizability1. decreases with applied electric field2. remains independent of temperature at a

given field3. increases with applied electric field at

constant temperatureWhich of the statements given above is/arecorrect?

a.

1 onlyb. 1 and 2 onlyc. 3 onlyd. 2 and 3 only

104. Consider the following statements for aphotoconducting material:1. Its dark conductivity is small2. With the absorption of radiation, equal

numbers of electrons and of holes areproduced

Which of the statements given aboveis/are correct?a. 1 onlyb. 2 onlyc. Both 1 and 2d. Neither 1 nor 2

105. The transition temperature of super-

conducting material is changed by which oneof the following?a. Electric fieldb. Magnetic fieldc. Mechanical stressd. None of the above

106. Width of resonance curve in an R-L-Cnetwork is determined by which one of thefollowing?a. R aloneb. L alone

c.

C aloned. All R, L and C

107. What is the typical value for the ratio ofcurrent in a p-n junction diode in the forwardbias and that in the reserve bias?a. 1b. 10c. 100d. 1000

108. Consider the following statements for a p-n

junction diode:1. It is an active component2. Depletion layer width decrease with

forward biasing3. In the reserve biasing case, saturation

current increases with increasingtemperature

Which of the statements given above arecorrect?a. 1, 2 and 3b. 1 and 2 onlyc. 2 and 3 only

d.

1 and 3 only

109. Illumination is measured using which one ofthe following?a. Millivoltmeterb. Stroboscopec. Luxmeterd. pH meter

110. A capacitive transducer is made of twoconcentric cylindrical electrodes. The outerdiameter of the inner cylindrical electrode is 4


12/12

12 of 12mm and dielectric medium is air. The innerdiameter of the outer electrode is 4.1 mm.When 150 V is applied across the electrodes,what is the electric field intensity?a. 1500 V/mmb. 3000 V/mmc. 4500 V/mmd. 6000 V/mm

111. A single even parity check but in telemetrydata transmission has which capability?a. Only detection of a single errorb. Both detection and correction of a single

errorc. Detection of even number of errors onlyd. Detection of any number of errors

112. When system noise is large and signal poweris low in a telemetry system, what is thepreferred form of modulation?

a.

Pulse-width modulationb. Pulse-amplitude modulationc. Pulse-code modulationd. Pulse-position modulation

113. The resonance frequency of a quartz crystaloscillator shows least variation withtemperature when the orientation of the crystalis chosen to havea. X-cutb. Y-cutc. NT-cut

d.

At-cut

114. The capacitance per unit volume is maximumfora. air capacitorb. mica capacitorc. ceramic capacitord. electrolytic capacitor

115. Consider the following statements pertainingto tunnel diodes:1. Impurity concentration is high

2.

Carrier velocities are low3. They have current controlled V-Icharacteristics

Which of the statements given above is/arecorrect?a. 1 onlyb. 2 and 2 onlyc. 1 and 3 onlyd. 1 and 2 only

116. Which one of the following is not a powerMOSFET type?

a. Lateral construction (LMOSFET)b. Lateral double diffusion construction

(LDMOSFET)c. T construction (TMOSFET)d. Enhancement mode construction

(EMOSFET)

117.

A system defined by [ ] [ ]

n

ky n x k

= = is anexample ofa. invertible systemb. memoryless systemc. non-invertible systemd. averaging system

118. Let x[n] be a real value sequence that is asample sequence of a wide-sense stationarydistance time random process. The powerdensity function of this signal isa. real, odd and non-negativeb.

real, even and non-negativec. purely imaginary, even and negatived. purely imaginary, odd and negative

119. Consider the following statements:When a series R-L-C circuit is underresonance1. current is maximum through R2. magnitude of the voltage across L is equal

to that across C3. the power factor of the circuit is unityWhich of the statements given above arecorrect?a. 1, 2 and 3b. 1 and 2 onlyc. 2 and 3 onlyd. 1 and 3 only

120. Consider the following statements with regardto a complete incidence matrix:1. The sum of the entries in any column is

zero2. The rank of the matrix is n-1 where n is

the number of nodes

3.

The determinant of the matrix of a closedloop is zero

Which of the statements given above arecorrect?a. 1 and 2 onlyb. 2 and 3 onlyc. 1 and 3 onlyd. 1, 2 and 3

Obj 2008 Paper I IES

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