IES OBJ Electronics &Telecomm.I 2000

8/11/2019 IES OBJ Electronics &Telecomm.I 2000

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3 1 2 5c. 4 1 2 3d. 4 2 5 3

10. Match List I (Antennas) with List II(Radiation patterns) and select the correctanswer:List IA. Simple dipoleB.

Omni-directional antennaC. Loop antennaList II1.

2.

3.

A B Ca. 1 2 3

b. 2 1 1c. 3 2 1d. 1 1 2

11. A vertical wire of 1 m length carries acurrent of 1 A at 10 MHz. The totalradiated power is nearlya. 0.13 W

b.

0.88 Wc. 7.3 Wd. 73 W

12. A Yagi antenna has a driven antennaa. only

b.

with a reflectorc. with one or more directorsd. with a reflector and one or more

directors

13. The Poynting vector P = E H

has thedimensions ofa. Power/unit area

b.

Voltsc.

Powerd. Volt/unit length

14.

In a hundred-turn coil, if the flux througheach turn is (t3 2t)m Wb, the magnitudeof the induced emf in the coil at a time of4s isa. 46 mV

b. 56 mVc. 4.6 Vd. 5.6 V

15.

Consider the following statementsregarding a plane wave propagatingthrough free space.The direction of field1. E is perpendicular to the direction of

propagation2. H is perpendicular to the direction of

propagation3.

E is perpendicular to the direction offield H

Which of these statements are correct?a. 1 and 2b. 2 and 3c. 1 and 3d. 1, 2 and 3

16. If the velocity of electro magnetic wave infree space is 3 10 m/s, the velocity in amedium with rof 4.5 and r of 2 wouldbe

a.

1 108

m/sb. 3 108m/sc. 9 108m/sd. 27 108m/s

17.

Phase velocity vp and the group velocityvg in a waveguide (c is velocity oflight) are related asa.

vpvg= c2

b.

vp+ vg= cc. vp/vg= a constantd.

vp + vg= constant18.

A cavity resonator can be represented by

a.

an LC circuitb. an LCR circuitc.

a lossy inductord. a lossy capacitor

19. The cut-off wavelength c for TE20modefor a standard rectangular waveguide isa.

2/ab. 2ac.

ad. 2a2

20.

A cylindrical cavity operating in TE111

mode has a 3dB bandwidth of 2.4 MHzand its quality factor is 4000. Its resonantfrequency would bea.

9.6 GHz

b. 9.6 / 2 GHz

c. 9.6/ 3 GHz

d. 9.6 / 6 GHz

21. If H

= 0.1 sin (108t + y)^

xa A/m for aplace wave propagating in free space, thenthe time average Poynting vector is

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a. (0.6 sin2y)^

ya W/m2

b. 0.6 ^

ya W/m2

c. 1.2 ^

xa W/m2

d. 1.2 ^

ya W/m2

22. If the height of transmitting and receiving

antennas in a LOS system are 49m and 9mrespectively then the distance up to whichcommunication may be possible is abouta. 40 km

b. 110 kmc.

400 kmd. 1100 km

23. The skip distance isa. same for each layer

b. independent of frequencyc.

independent of the state of ionisationd. independent of transmitted power

24.

The dimension of flux density isa.

MT1Q1b.

MT2Q2c. MT1 Q1d.

MT1 Q225. Match List I (Instrument) with List II

(Property/use) and select the correctanswer :List IA. PMMCB. Moving iron

C.

ThermocoupleD. Electrostatic typeList II1. Square law type scale2. Very goad high frequency response3. Linear scale over the entire range4. Voltmeter

A B C Da. 4 1 2 3

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

26.

A coil would behave asa. an inductor at high frequencies

b. a capacitor at very low frequenciesc.

a capacitor at very high frequenciesd. a resistor at high frequencies

27. A series LCR circuit withR = 10 , |XL| = 20 , and |XC| = 20 isconnected across an supply of 200 Vrms.The rms voltage across the capacitor isa. 200 90 V

b. 200 90 V

c. 400 90 Vd. 400 90 V

28. An ammeter of range 0.25 A has aguaranteed accuracy of 1% of full-scalereading. The current measured by theammeter is 5 A. The limiting error in thereading is

a.

2%b.

2.5%c. 4%d. 5%

29. An inductor tunes at 200 kHz with 624 pFcapacitor and at 600 kHz with 60.4 pFcapacitor. The self-capacitance of theinductor would bea. 8.05 pFb. 10.05 pFc.

16.10 pFd.

20.10 pF

30.

The current internationally recognisedunit of time and frequency is based on thecesium clock, which gives an accuracybetter than 1 s per day. This statement isrelated toa. Working standardsb.

International standardsc. Primary standardsd.

Secondary standards31.

The bandwidth of a CRO is from 0 to 20MHz. The fastest rise time which a squarewave can have, in order that it is

accurately reproduced by the CRO isa. 0.175 sb. 17.5 nsc. 35 nsd. 52.5 ns

32. A dc voltage of 1V is applied to the X-plates to a CRO and an ac voltage 2 sin100 t is applied to the Y-plates. Theresulting display on the CRO screen willbe aa. vertical straight lineb.

horizontal straight linec.

sine waved. slant line

33. In a distortion factor meter, the filter at thefront end is used to suppressa. odd harmonicsb. even harmonicsc. fundamental componentd. dc component

34.

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The Wein bridge circuit shown in theabove figure can be used as a frequencymeasuring device, provideda.

R2/R4= 2b. R4/R2= 2c. R2/R4= 4d. R2/R4= 3

35. The equations under balance condition fora bridge are

R1= R2R3/R4and L1= R2R3R4 .

where R1 and L1 are unknown quantities.Which one of the following sets of

parameters should be chosen as variablesin order to achieve converging balance?a. R2and R3

b. R2and C4c. R4 and C4d. R3and C4

36.

At the balance condition of the ac bridgeshown in the above figure the value of Z4would bea.

120 70

b.

187.5 10 c. 187.5 70 d. 333.3 70

37. Wagners earth in ac bridge circuits is usedto eliminate the effect ofa.

stray electrostatic fieldsb. stray electromagnetic fieldsc.

inter-component capacitancesd.

parasitic capacitance to earth

38.

Radiation pyrometers are used for themeasurement of temperature in the rangeofa. 200 C to 500 Cb. 0 C to 500 Cc. 500 C to 1200 Cd. 1200 C to 2500 C

39. Magnetic flux can be measured bya.

capacitive pick-upb. inductive pick-upc. resistive pick-upd. Hall-effect pick-up

40. A semiconductor based temperaturetransducer has a temperature coefficient of2500 V/ C. This transducer indeed is aa. thermistorb. forward - biased pn junction diode

reverse - biased pn junction diodec. FET

41.

The function of the reference electrode in apH meter is toa. produce a constant voltageb. provide temperature compensationc. provide a constant currentd. measure average pH value

42. Pirani gauge is used for the measurementof pressure in the range ofa. 108mm to105mm of Hgb. 103mm to 101mm of Hgc. 10 mm to 103mm of Hgd. 105mm to 108mm of Hg

43.

The most Light sensitive transducer forconversion of light into electrical power isthea. Photodiode (b) solar cellb. photoconductive cell (d) photovoltaic

cell44.

In an amplitude modulated system, if thetotal power is 600 W and the power incarrier is 400 W, then the modulationindex isa.

0.5b. 0.75

c.

0.9d.

145. The bandwidth of a N bit binary coded

PCM signal for modulating a signal havingbandwidth of f Hz is

a.f

NHz

b.2

f

NHz

c. Nf Hzd. N2f Hz

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5 of 1446.

Time division multiplexing requiresa. constant data transmission

b. transmission of data samplesc. transmission of data at randomd. transmission of data of only one

measureand47. The difference between the number of

atoms in a unit cell of a bcc crystal and anfcc crystal isa. 1

b. 2c. 4d. 6

48. If a small amount of Cu is added to a Niconductor, then thea. resistivity of Ni will increase at all

temperatures because Cu is a betterconductor than Ni

b. residual resistivity of Ni at low

temperature will increase as Cu atomsact as defect centresc. resistivity of Ni will increase at all

temperatures as Cu destroys theperiodicity of Ni and acts as defects

d. resistivity of Ni remains unaltered asCu atoms give the same number of freeelectrons as Ni atoms

49.

For the n - type semiconductor with n =NDand p = ni

2/ ND, the hole concentrationwill fall below the intrinsic value becausesome of the holes

a.

drop back to acceptor impurity statesb. drop to donor impurity statesc.

virtually leave the crystald. recombine with the electrons

50. Match list I (Magnetic materials) with listII (Dipole arrangement in external field)and select the correct answer:List IA. ParamagneticB. FerromagneticC. AntiferromagneticD. Ferrimagnetic

List II1. All dipoles are aligned in one preferred

direction and have equal magnitudes2. Half of the dipoles are aligned in

opposite direction arid have equalmagnitudes

3. Half of the dipoles (with equalmagnitudes) are aligned in oppositedirection to other half having equal butlower magnitudes

4.

All dipoles have equal magnitudes butare randomly oriented

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

51. For an insulating material, dielectricstrength and dielectric loss should berespectivelya. high and highb. low and highc. high and lowd. low and low

52. Match List I (Optical devices) with List II(Electrical/optical characteristics) andselect the correct answer :List IA. LASER

B.

Solar cellC. Photo diodeD. LEDList II1. Emits monochromatic light of low

intensity2.

Consumes electrical power due to theincident light

3.

Delivers power to a load4. Emits monochromatic light of high

intensityA B C D

a.

4 3 1 2b. 3 4 2 1c.

4 3 2 1d. 3 4 1 2

53. Which one of the following is the bestdefinition of a superconductor?a. It is a material showing perfect

conductivity and Meissner below acritical temperature

b. It is a conductor having zero resistancec. It is a perfect conductor with highest

diamagnetic susceptibility

d.

It is a perfect conductor but becomesresistive when the current densitythrough it exceeds a critical value

54. If a coil has diameter d, number of turnsN and form factor F then theinductance of the coil is proportional toa. N2dFb. Nd2Fc. N2d2/ Fd. N2d/F

55.

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The above figure shows the circuit symbolofa.

FETb. PMOSFETc. CMOSFETd. NMOSFET

56. The ac resistance of a forward-biased p-njunction diode operating at a bias voltageV and carrying current I isa. zero

b. a constant value independent of V andI

c.

V/Id.

V/I57.

Match List I with List II and select thecorrect answer:List IA.

Drift currentB. Einsteins equationC. Diffusion currentD. Continuity equationList II1. Law of conservation of charge2. Electric field

3.

Thermal voltage4. Concentration gradient

A B C Da. 2 1 4 3

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

58. Consider the following statements :If an electric field is applied to an n-typesemiconductor bar, the electrons and holesmove in opposite directions due to theiropposite charges. The net current is1.

due to both electrons and holes withelectrons as majority carriers.

2. the sum of electron and hole currents.3. the difference between electron and

hole current.Which of these statements is/are correct?a.

1 aloneb. 1 and 2c.

2 aloned.

3 alone

59.

Consider the following circuitconfigurations:1. Common emitter2. Common base3. Emitter follower4. Emitter follower using Darlington pairThe correct sequence in increasing orderof the input resistances of theseconfigurations isa. 2, 1, 4, 3b. 1, 2, 4, 3c. 2, 1, 3, 4d. 1, 2, 3, 4

60. Match List I with List II and select thecorrect answer:List I (Devices)A. Silicon diodeB. Germanium diodeC. LED

D.

PIN diodeList II (Property)1. High frequency applications2.

Very low reverse bias saturationcurrent

3. Low forward bias voltage drop4.

Cut-off wavelengthA B C D

a.

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

2 3 4 1

61.

The depletion layer across a p+

njunction liesa.

mostly in the p+ regionb. mostly in the n regionc. equally in both the p+and nregionsd. entirely in the p+region

62. A transistor has a current gain of 0.99 inthe CB mode. Its current gain in the CCmode isa. 100b. 99c. 1.01

d.

0.9963. Match List-I (Biasing of the junctions)

with List II (Functions) and select thecorrect answer :List IA. E-B junction forward bias and C-B

junction reverse biasB. Both E-B and C-B junctions forward

biasC. E-B junction reverse bias and C-B

junction forward bias

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Both E-B and C-B junctions reversebias

List II1. Very low gain amplifier2. Saturation condition3. High gain amplifier4. Cut-off condition

A B C Da.

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

64. Match List I (Structures/characteristics)with List II (Reasons) in respect of JFETand select the correct answer :List IA. n-channel JFET is better than p-

channel JFET

B.

Channel is wedge shapedC. Channel is not completely closed atpinch-off

D. Input impedance is highList II1. Reverse bias increases along the

channel2. High electric field near the chain and

directed towards source3. Low leakage current at the gate

terminal4. Better frequency performance since n

>> pA B C D

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

65.

The above graph depictsa. drain characteristic of a MOSFET

b. drain characteristic of an IGBTc. volt-ampere characteristic of a triacd. volt-ampere characteristic of an SCR

66. Consider the following statements :A four-layer PNPN device having two gateleads can be turned on by applying a

1.

positive current pulse to the cathodegate

2. positive current pulse to the anode gate3. negative current pulse to the anode

gate4. negative current pulse to the cathode

gateWhich of these statements is/are correct?a.

1 aloneb. 1 and 3c. 2 aloned. 2 and 4

67. Almost all resistors are made in amonolithic integrated circuita. during the emitter diffusionb. while growing the epitaxial layerc. during the base diffusiond. during the collector diffusion

68. Assertion (A) : BaTiO3 is a piezoelectric

material and is used in a record player.Reason (R) : In a piezoelectric transducer,stress induces polarization and an electricfield strains the material.a. Both A and R are true and R is the

correct explanation of Ab.

Both A and R are true but R is NOTthe correct explanation of A

c.

A is true but R is falsed. A is false but R is true

69. Assertion (A) : Hall crystal can be used asa multiplier of two signals.

Reason (R) : Hall voltage is proportionalto the currents or voltages applied inperpendicular directions across the Hallcrystal.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. A is false but R is true

70.

Assertion (A) : The hybrid it - model of atransistor can be reduced to its h-parameter

model and vice-versa.Reason (R) : Hybrid and h-parametermodels are inter-related as both of themdescribe the same transistor.a. Both A and R are true and R is the


the correct explanation of Ac.


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Assertion (A) : When light falls at thejunction of a p-n photo diode, its P sidebecomes positive and N side becomesnegative.Reason (R) : When a photo diode is short-circuited, the current in the external circuitflows from the P-side to the N-side.a. Both A and R are true and R is the


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

72. Assertion (A) : Prescalers are used indigital counters to extend the frequencyrange.Reason (R) : Prescalers are simpledividing circuits and as such do not havethe high frequency limitation of digital

counters.a. Both A and R are true and R is thecorrect explanation of A

b. Both A and R are true but R is NOTthe correct explanation of A

c. A is true but R is falsed.

A is false but R is true73. Assertion (A) : CRTs, used in TV

receivers are of electrostatic deflectiontype and those used in oscilloscopes are ofmagnetic deflection type.Reason (R) : TV receivers need a large

screen to view pictures, whereas accuracyis the main consideration in oscilloscopes.a.

Both A and R are true and R is thecorrect explanation of A


c. A is true but R is falsed. A is false but R is true

74. Assertion (A) : Alnico is commonly usedfor electromagnets.Reason (R) : Alnico has low hysteresisloss.

a.



c. A is true but R is falsed. A is false but R is true

75. Assertion (A) : The solution of Poissonsequation is the same as the solution ofLaplaces equation.

Reason (R) : Laplaces equation is aspecial case of Poissons equation forsource-free regions.a. Both A and R are true and R is the


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

A is false but R is true76. Assertion (A) : The functions given by

2 2

2 2

( 2)( 10)( )

( 1)( 6)

Ks s sZ s

s s

represents an

L- C driving point impedance function.Reason (R) : Poles and zeroes interlace onthe imaginary axis of the complex s-plane.a. Both A and R are true and R is the

correct explanation of Ab.

Both A and R are true but R is NOTthe correct explanation of A

c.


77. Assertion (A) : The fundamental loop of alinear directed graph contains four twigsand two links corresponding to a giventree.Reason (R) : In a linear directed graph, alink form is a closed loop.a. Both A and R are true and R is the


the correct explanation of Ac.


78. Assertion (A) : The zero - state responseof a linear constant-parameter continuous-time system can have components havingthe natural frequencies of the system.Reason (R) : The forced frequencycomponents in the response of the state forany given input may not add up to thegiven zero initial value of the state. Thenatural frequency components may be

needed to bridge the gap.a. Both A and R are true and R is thecorrect explanation of A


c.


79.

Assertion (A) : When a linear time-invariant system having a system function

H(s) is driven by an input x(t) = 0s te the

force part of the output is H(s0) 0s te .

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9 of 14Reason (R) : In the partial fractionexpansion of the Laplace transform of theoutput, the term corresponding to the pole

at s0 is0

0

( )H s

s s .The inverse transform

0

0

( )H s

s sis H(s0) 0

s te .

a.



c.


80.

In the circuit shown in the above figure,the power consumed in the resistance R ismeasured when one source is acting at atime, these values are 18 W, 50 W and 98W. When all the sources are actingsimultaneously, the possible maximum andminimum values of power in R will bea. 98 W and 18 W

b.

166 W and 18 Wc.

450 W and 2 Wd. 166 W and 2 W

81. In a two-terminal network, the open-circuitvoltage measured at the given terminals byan electronic voltmeter is 100 V. A short-circuit current measured at the sameterminals by an ammeter of negligibleresistance is 5 A. If a load resistor of 80 is connected at the same terminals, thenthe current in the load resistor will bea. 1 A

b.

1.25 Ac.

6 Ad. 6.25 A

82.

Consider the following statements :1.

Tellegens theorem is applicable to anylumped network

2. The reciprocity theorem is applicableto linear bilateral networks

3. Thevenins theorem is applicable totwo-terminal linear active networks

4.

Nortons theorem is applicable to two-terminal linear active networks

Which of these statements are correct?a. 1, 2 and 3b. 1, 2, 3 and 4c. 1, 2 and 4d. 3 and 4

83.

Which one of the following theorems canbe conveniently used to calculate thepower consumed by the 10 resistor inthe network shown in the above figure?a.

Thevenins theoremb.

Maximum power transfer theoremc. Millmans theorem

d.

Superposition theorem84.

Which one of the following is a cut set ofthe graph shown in the above figure?a. 1, 2, 3 and 4b. 2, 3, 4 and 6c.

1, 4, 5 and 6d. 1, 3, 4, and 5

85. A network has 10 nodes and 17 branches.The number of different node pair voltageswould bea. 7b.

9c.

10

d.

4586.

In the circuit shown in the above figure,the current supplied by the sinusoidalcurrent source I isa. 28 A

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4 Ac. 20 Ad. No determinable from the data given

87. Consider the following statements :A 3-phase balanced supply system isconnected to a 3-phase unbalanced load.Power supplied to this load can bemeasured using1.

two wattmeters2.

one wattmeter3. three wattmetersWhich of these statements is/are correct ?a.

1 and 2b. 1 and 3c. 2 and 3d.

3 alone88.

In the above circuit, if the powerdissipated in the 6 resistor zero then V isa.

20 245ob.

2030oc. 2045od. 20 230o

89. A capacitor used for power factorcorrection in single-phase circuit decreasesa. the power factor

b.

the line currentc. both the line current and the powerfactor

d. the line current and increases powerfactor

90. For a two-port reciprocal network, theoutput open-circuit voltage divided by theinput current is equal toa. B

b. z12c.

1/y12d.

h12

91.

If the transmission parameters of the abovenetwork are A = C = 1, B = 2 and D = 3,then the value of Zinis

a.

12

13

b.13

12

c.

3 d.

4 92. The impedance matrices of two, two-port

networks are given by3 2

2 3

and15 5

5 25

If these two networks are connected inseries, the impedance matrix of theresulting two-port network will be

a.

3 5

2 25

b.18 7

7 28

c. 15 25 3

d. indeterminate93.

In the circuit shown in the above figure,switch K is closed at t = 0. The circuit was

initially relaxed. Which one of thefollowing sources of, v(t) will producemaximum current at t = 0+?a. Unit stepb.

Unit impulsec. Unit rampd.

Unit step plus unit ramp94.

In the circuit shown in the above figure,steady -state was reached when the switchS was open. The switch was closed at t =0. The initial value of the current throughthe capacitor 2 C isa.

zerob. 1 Ac.

2Ad.

3A95.

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In the above circuit, S was initially open.

At time t = 0, S is closed. When thecurrent through the inductor is 6 A, therate of change of current through theresistor is 6 A/s. The value of the inductorwould bea.

1Hb.

2Hc. 3Hd. 4H

96.

Consider the following statements:If a network has an impedance of (1 j) ata specific frequency, the circuit would

consist of series1.

R and C2. R and L3. R, L and CWhich of these statements are correct?a.

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

97.

In the above circuit, V1= 40 V when R is10 . When R is zero, the value of V2will

bea.

40 Vb. 30Vc.

20 Vd.

10 V98. A network contains only independent

current sources and resistors. If the valuesof all resistors are doubled, the values ofthe node voltagesa. will become half

b. will remain unchangedc. will become doubled. cannot be determined unless the circuit

configuration and the values of theresistors are known

99.

In the transformer shown in the abovefigure, the inductance measured across theterminal 1 and 2 was 4 H with openterminals 3 and 4. It was 3 H when theterminal 3 and 4 were short circuited. Thecoefficient of coupling would bea. 1b. 0.707c. 0.5d. Indeterminate due to insufficient data

100.

The circuit shown in the above figure, willact as an ideal current source with-respectto terminals A and B, when frequency isa. zerob. 1 rad/sc. 4 rad/sd. 16 rad/s

101.

The circuit shown in the above figure is aa. low pass filterb. high pass filterc. band pass filterd. band stop filter

102.

Z(s) for the network shown in the abovefigure is

2

2

3( 6 8)

4 3

s s

s s

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12 of 14The value of C and R are, respectivelya.

1/6 F and 4 b. 2/9 F and 9/2 c.

2/3 F and 1/2 d. 1/2 F and 1

103. A continuous-time system is governed bythe equation

3y

3

(t) + 2y

2

(t) + y (t) = x

2

(t) + x (t).{y(t)and x(t) respectively are output andinput). The system isa.

linear and dynamicb. linear and non-dynamicc. non-linear and dynamicd.

non-linear and non-dynamic104.

The impulse response of a discrete systemwith a simple pole shown in the abovefigure.The pole of the system must be located onthea. real axis at z = 1

b. real axis between z = 0 and z = 1c. imaginary axis at z = jd. imaginary axis between z = 0 and z = j

105.

Which one of the following systems is acausal system?[y(t) is output and u(t) is a input stepfunction]a. y(t) = sin (u(t + 3))

b.

y(t) = 5u(t) + 3u(t 1)c.

y(t) = 5u(t) + 3u(t + 1)d. y(t) = sin (u(t 3)) + sin (u(t + 3))

106.

Which one of the following transferfunctions represents the critically dampedsystem?

a.

H1(s) = 2 14 4s s

b. H2(s) = 21

3 4s s

c.

H3(s) = 21

2 4s s

d.

H4(s) = 21

4s s

107.

Two linear time-invariant discrete timesystems s1and s2are cascaded as shown inthe above figure. Each system is modelledby a second order difference equation. Thedifference equation of the overall cascadedsystem can be of the order ofa. 0, 1, 2, 3 or 4b.

either 2 or 4c. 2d.

4108.

Consider the following equations for thestate transition matrix of the linear time-invariant continuous time system (t) :1. (t) = [(t)]12. {(t)]k= (tk) for any positive integer

k

3.

(t t0) = (t) (t0) for any constantt0.Which of these equations correctly definethe properties of the given system ?a. 1, 2 and 3b. 1 and 2c.

1 and 3d. 2 and 3

109. Which one of the following is the correctstate-space realization of a discrete systemgiven by the difference equationc(k + 2) + c(k + 1) + c(k) = u(k) ?a.

b.

c.

d.

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13 of 14110.

The Fourier series representation of aperiodic current is

[2 6 2 cos 48 sin 2 ] .t t A The effective value of the current is

a.

(2 + 6 + 24 )Ab. 8 Ac. 6 A

d.

2 A111. Match List I (Properties) with List II

(Characteristics of the trigonometric form)in regard to Fourier series of periodic f(t)and select the correct answer :List IA.

f(t) + f(t) = 0B.

f(t) f(t) = 0C. f(t) + f(tT/2) = 0D.

f(t)f(t T/2) = 0List II1. Even harmonics can exist

2.

Odd harmonics can exist3.

The dc and cosine terms can exist4. sine terms can exist5. cosine terms of even harmonics can

existA B C D

a. 4 5 3 1b. 3 4 1 2c. 5 4 2 3d. 4 3 2 1

112. Consider the following statementsregarding the fundamental component f

1(t)

of an arbitrary periodic signal f(t):It is possible for1. the amplitude of f1(t) to exceed the

peak value of f(t).2. f1(t) to be identically zero for a non-

zero f(t).3. the effective value of f1(t) to exceed

the effective value of f(t).Which of these statements is / are correct?a. 1 alone

b. 1 and 2

c.

2 and 3d. 1 and 3113. Match list I with List II and select the

correct answer:List IA.

f(t) = f(t)

B. 0jn tnn

C e

C. ( ) j tf t e dt

D. 1 2

0

( )t

f f t d

List II1. Exponential form of Fourier series2. Fourier transform3. Convolution integral4. z transform

5.

Odd function wave symmetryA B C D

a. 5 1 2 3b. 2 1 5 3c. 5 4 2 1d. 4 5 1 2

114. A voltage signal v(t) has the followingFourier transform:

for | | 1( )

0 for | | 1

j de

V j

The energy that would be dissipated in a

1resistor fed from v(t) isa.

2/Joulesb. 2e2d/ Joulesc. 1 / Joulesd. 1 / 2Joules

115.

The output of a linear system to a unit stepinput u(t) is t2e2t. The system functionH(s) is

a. 2

2

2s s

b.

22

2s s

c.

3

2

2s

d.

3

2

2

s

s

116. Match List I (System function) with List II(Impulse response) and select the correctanswer :List I

A. 1

se

s

B.2

1

1s s

C.2

1

( 1)s

D.2

1

s s

List II1.

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14/14

14 of 14

2.

3.

4.

5.

A B C Da. 3 4 1 2

b. 5 2 3 4c.

3 2 1 4d. 5 4 3 2

117. If the step response of a causal, lineartime-invariant system is a(t), then theresponse of the system to a general inputx(t) would be

a. 0

( )

tda

x t d

d

b.

0

( )(0) ( )

tda

a x t x t d d

c.

0

(0) ( )t

x a t x a t d

d.

0

(0) ( )

t dax a t x t d

d

118.

Consider the compound system shown inthe above figure; Its output is equal toinput with a delay of two units. If thetransfer function of the first system as

given by H1(z) =0.5

0.8

z

z

, then the transfer

function of the second system would be

a. H2(z) =2 3

1

0.2

1 0.4

z z

z

b.

H2(z) =2 3

1

0.8

1 0.5

z z

z

c. H2(z) =1 3

1

0.2

1 0.4

z z

z

d. H2(z) =2 3

1

0.8

1 0.5

z z

z

119.

Match List I with List II and select thecorrect answer:List I {x(n)}A. nu(n)B. nu(n1)C. nnu(n 1)D. nnu(n)List II {X(z)}

1.

1

211

z

z

ROC : |z| > ||

2.

11

1 z

ROC : |z| > ||

3. 1

1

1 z

ROC : |z| < ||

4.

1

211

z

z

ROC : |z| < ||A B C D

a.

2 4 3 1b.

1 3 4 2c. 1 4 3 2d. 2 3 4 1

120.

A linear system has the transfer function

1

( )1

H jj

. When it is subjected to

an input white noise process with aconstant spectral density A, the spectral

density of the output will bea.

1

1j

b.

21

A

j

c. 2 1

A

d. 2 1

A

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IES OBJ Electronics &Telecomm.I 2000

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