IES OBJ Electronics &Telecomm.I 2003

8/11/2019 IES OBJ Electronics &Telecomm.I 2003

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PAPER-I

1. In a silicon crystal, the arrangement ofatoms repeats periodicity. This type ofmaterial is classified asa. Amorphous and non-crystalline

b. Non-crystalline and epitaxialc. Epitaxial and single crystald. Amorphous and single crystal

2. A conductor carries a current of 4 A and ifmagnitude second is of charge of anelectron e = 1.6 10 19 is Coulomb, then

the number of electrons which flow pastthe cross-section pera. 2.5 10 19

b. 1.6 10 19 c. 6.4 10 19 d. 0.4 10 19

3. The correct sequence of the followingmaterials in the increasing order ofconductivity isa. Silicon doped with boron - Silver -

Aluminium - Intrinsic silicon b. Intrinsic silicon - Aluminium - Silver -

Silicon doped with boronc. Aluminium - Intrinsic silicon - Silicon

doped with boron - Silverd. Intrinsic silicon - Silicon doped with

boron - Aluminium - Silver4. Consider the following statements for an

n-type semiconductor :1. Donor level ionization decreases with

temperature

2. Donor level ionization increases withtemperature

3. Donor level ionization is independentof temperature

4. Donor level ionization increases as ED (donor energy level) moves towardsthe conduction band at a giventemperature.

Which of these statements is/are correct ?a. 1 only

b. 2 onlyc. 2 and 4d. 3 only

5. Consider the following statements for ann-type semiconductor :1. EF lies below ED at a room temperature

(T).2. EF lies above ED as T 03. EF = ED at some intermediate

temperature

4. EF is invariant with temperature.Where EF is Fermi energy and ED is donorlevel energy.Which of these statements is/are correct ?a. 1 and 2 b. 2 and 3c. 1, 2 and 3d. 4 only

6. Which of the following materials are piezoelectric ?

a. Mica and quartz b. Mica, barium titanate and quartzc. Mica and diamondd. Barium titanate and quartz

7. The correct sequence of the followingmaterials in the increasing order ofmagnetic susceptibility isa. Diamagnetic - Ferromagnetic -

Paramagnetic - Superconductor b. Ferromagnetic - Paramagnetic -

Diamagnetic Superconductorc. Paramagnetic - Diamagnetic -Superconductor - Ferromagnetic

d. Superconductor - Diamagnetic -Paramagnetic - Ferromagnetic

8. Match List I with List II and select thecorrect answer :List I (Dipole Characteristics)A. All dipoles have equal magnitude but

are randomly oriented

I.E.S. (OBJ)-2003

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2 of 15B. 50% of the dipoles having equal

magnitude are antiparallel to other50% (having equal but lowermagnitude)

C. 50% of the dipoles are antiparallel toother 50% but all have equalmagnitude

D. All dipoles have equal magnitude buthave parallel alignmentList II (Materials)1. Ferri-magnetic2. Anti-ferromagnetic3. Ferro-magnetic4. Para-magnetic

A B C Da. 1 4 2 3

b. 4 1 3 2

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

9. Under the influence of an external electricfield an insulator undergoes the process of

polarization. There are four contributingfactors to the total polarization viz.electronic. ionic, orientation and spacecharge At the optical frequencies, the onlycontribution to total polarization is froma. Space charge polarization

b. Ionic polarizationc. Orientation polarizationd. Electronic polarization

10. Consider the following statements :A semiconductor to be used inoptoelectronic devices should have1. direct energy band gap.2. indirect energy band gap.3. any value of forbidden energy band

gap.4. right value of band gap corresponding

to light wavelengthWhich of these statements is/are correct ?a. 1 only

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

11. An LED made using GaAs emits radiationina. Visible region

b. Ultraviolet regionc. Infra red regiond. Microwave frequency region

12. A resistance thermometer has atemperature coefficients of resistance 10 3 per degree and its resistance at 0C is1.0 . At what temperature is its resistance1.1 ?a. 10C b. 100Cc. 120Cd. 10C

13. The diffusion capacitance of a. p-n junction diodea. increases exponentially with forward

bias voltage b. Decreases exponentially with forward

bias voltagec. Decreases linearly with forward bias

voltaged. Increases linearly with forward bias

voltage14. The reverse current of a silicon diode is

a. Highly bias voltage sensitive b. Highly temperature sensitivec. Both bias voltage and temperature

sensitive

d.

Independent of bias voltage andtemperature15. A combination of two diodes connected in

parallel when compared to a single diodecan withstanda. Twice the value of peak inverse

voltage b. Twice the value of maximum forward

currentc. A larger leakage currentd. Twice the value of cut-in voltage

16. Assume ni = 1.45 1010/cm3 for silicon. Inan n-type silicon sample, the donorconcentration at 300 K is 5 1014/cm3 andcorresponds to 1 impurity atom for 108 silicon atoms. The electron and holeconcentrations in the sample will bea. n = 5 1014/cm3 and p = 4.2 105/cm3 b. n < 5 1014/cm3 and p > 4.2 105/cm3 c. n > 5 1014/cm3 and p < 4.2 105/cm3 d. n < 5 1014/cm3 and p < 4.2 105/cm3



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3 of 1517. The resistivity at room temperature of

intrinsic silicon is 2.3 103 m and thatof en n-type extrinsic silicon sample is8.33 10 2 m. A bar of this extrinsicsilicon sample is 3 mm long and has arectangular cross-section 50 100 mm anda steady current of 1 A exists in the bar.

The voltage across the bar is found to be50 mV. If the same bar is of intrinsicsilicon, the voltage across the bar will beabouta. 1400 V

b. 140 Vc. 14 Vd. 1.4V

18. A semiconductor specimen of breadth d,width w and carrying current l is placed ina magnetic field B to develop Hall voltageVH in a direction perpendicular to l and B.VH is NOT proportional toa. B

b. l c. 1/wd. 1/d

19. In switching diode fabrication, a dopant isintroduced into silicon which introducesadditional trap levels in the materialthereby reducing the mean life time ofcarriers. This dopant isa. Aluminium

b. Platinumc. Goldd. Copper

20. The light emitting diode (LED) emits lightof a particular colour becausea. It is fabricated from a fluoroscent

material b. Transition between energy levels of the

carriers takes place while crossing the p-n junction

c. Heat generated in the diode isconverted into light

d. The band gap of the semi-conductormaterial used in the fabrication of thediode is equal to the energy hv of thelight photon

21. Depletion capacitance in a diode dependson1. Applied junction voltage

2. Junction built-in potential.3. Current through junction4. Doping profile across the junctionSelect the correct answer using the codesgiven below :a. 1 and 2 b. 1 and 3c. 1, 2 and 4d. 2, 3 and 4

22. The depletion region in a semiconductor p-n junction diode hasa. Electrons and holes b. Positive and negative ions on either

sidec. Neither electrons nor ionsd. No holes

23. When a junction diode is used in switchingapplications, the1orward recovery time isa. Of the order of the reverse recovery

time b. Negligible in comparison to the reverse

recovery timec. Greater than the reverse recovery timed. Equal to the mean carrier life time

for the excess minority carriers24. The Gunn diode is made from

a. Silicon b. Germaniumc. Gallium Arsenided. Selenium

25. The internal resistance of a current sourceused in the. model of BJT while analyzinga circuit using BJT isa. Very high b. Very lowc. Zerod. Of the order of a few mega-ohms

26. For a BJT in common emitter mode, baseto emitter capacitance (C ) is ten times thecollector to base capacitance (C).Transistor is biased at quiescent collectorcurrent ICQ = 1 mA and its short circuitunity gain frequency is 0.909 M (rad/s).What is the C Value ?a. 6.45 nF b. 44 nFc. 40 nF



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4 of 15d. 7.1 nF

27. A bipolar junction transistor has acommon base forward short circuit currentgain of 0.99. Its common emitter forwardshort circuit current gain will bea. 50

b. 99c. 100d. 200

28. The scaling factor of an MOS device is .Using constant voltage scaling model, thegate area of the device will be scaled asa. 1/

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

29. A CMOS amplifier when compared to an N-channel MOSFET, has the advantage ofa. Higher cut-off frequency

b. Higher voltage gainc. Higher current gaind. Lower current drain from the power

supply, thereby less dissipation30. In the forward blocking region of a silicon

controlled rectifier, the SCR isa. In the off-state

b. In the on-statec. Reverse biasedd. At the point of breakdown

31. In fabricating silicon BJT in ICs by theexpitaxial process, the number ofdiffusions used is usuallya. 2

b. 3c. 4d. 6

32. In the fabrication of n-p-n transistor in anIC, the buried layer on the p-type substrateisa. P+-doped

b. n+-dopedc. Used to reduce the parasitic

capacitanced. Located in the emitter region

33. Velocity of light travelling in an opticalfibre isa. Equal to c

b. Greater than c by a few per cent Lessthan c by a few per cent

c. Much greater than c, approaching themagnitude of C2

34. In an opto-electronic communicationsystem, the system component in whichfree electrons are involved in its operation

isa. Laser b. Optical fibrec. Photo detectord. Coupling device employed with the

optical fibre35.

The v-i characteristic of an element isshown in the above figure. The element isa. Non-linear, active, non-bilateral b. Linear, active, non-bilateralc. Non-linear, passive, non-bilaterald. Non-linear, active, bilateral

36. The sum of two or more arbitrarysinusoids is

a.

Always periodic b. Periodic under certain conditionsc. Never periodicd. Periodic only if all the sinusoids are

identical in frequency and phase37. The average value of the full-wave

rectified sine wave with period , and a peak value of Vm isa. 0.707 Vm b. 0.500 Vm c. 0.637 V

m

d. 0.318 Vm 38. Match List I with List II and select the

correct answer:List IA. Free and Forced responseB. Z-transformsC. Probability theoryD. Fourier seriesList II



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5 of 151. Discrete time systems2. Dirichlet conditions3. Non-homogeneous differential

equation4. Random processes

A B C Da. 1 3 2 4

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

39. The relationship between the input x(t) andthe output y(t) of a system is

2 2

2 2( 2) ( 2)d y d x

x t u t dt dt

The transfer function of the system is

a. 2

21

s

s

e

b. 2

21se

s

c. 2

21se

s

d. 2

21 ss

e

40.

Which one of the following is the state-space model of the circuit shown above?

a.

1 1

2 2

1

2

1 00( ) ( )( )1( ) ( )1 0

( )( ) 0 1

( )

x t x t L u t x t x t

C C

x t y t

x t

b.

1 1

2 2

1

2

0 1( ) ( ) 0( )1 1( ) ( ) 1

( )( ) 0 1

( )

x t x t u t

x t x t C L

x t y t

x t

c.

1 1

2 2

1

2

10( ) ( ) 1( )

( ) ( )1 00

( )( ) 1 0

( )


C

x t y t

x t

d.

1 1

2 2

1

2

10( ) ( ) 0( )

( ) ( )1 10

( )( ) 1 0

( )


C x t

y t x t

41. With the conventional notation X = AX +BU for the state description of a lineartime-invariant network, examine thevalidity of the following statementsrelating to the matrix A:1. A is symmetrical if the network is

reciprocal.2. The sum of the natural frequencies of

the network is equal to the determinantof A.

Which of these statements is/are true ?a. Both 1 and 2 b. 1 onlyc. 2 only

d. Neither 1 nor 242. Which one of the following is NOT a

correct statement about the state-spacemodel of a physical system ?a. State-space model can be obtained

only for a linear system b. Eigen values of the system represent

the roots of the characteristic equationc. X = AX + Bu represents linear state-

space model of a physical systemd. X(t) represents the state vector of the

system43. Match List I (Nature of Periodic Function)

with List II (Properties of SpectrumFunction) and select the correct answer :

List I

A. Impulse trainB. Full-wave rectified sine functionC. Sin 2 t/6 cos 2 t/6



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D. List II1. Only even harmonics are present2. Impulse train with strength l/T

3. 3 = 1/2j ; 3 = 1/2j ;1 = 1/2j ; 1 = 1/2j

4. Only odd harmonics are present5. Both even and odd harmonics are

presentA B C D

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

44. The covariance function of a band limitedwhite noise isa. A Dirac delta function

b. An exponentially decreasing functionc. A sinc functiond. A sinc2 function

45. The inverse Fourier transform of (f) isa. u(t)

b. 1c. (t)d. e j2 t

46. If 227 97

33s

s s

is the Laplace transform of

f(t), then f(0+) isa. Zero

b. 97/33c. 27d. infinity

47.

The Laplace transform of the waveformshown in the above figure isa. 1/s [es + e2s + 2e3s]

b. 1/s [es + e2s + 2e 3s]

c. 1/s [e s + e 2s + 2e 3s]d. 1/s [e s + e 2s 2e 3s]

48. Match List I (F(s)) with List II (f(t)) andselect the correct answer:List I

A. 10

( 10)s s

B. 210

( 100)s

C.

2

10( 10) 100

s

s

D. 10List II1. 10 (t).2. (e 10t cos 10 t) . u(t)3. (sin 10 t) . u(t)4. (1 e 10t) . u(t)

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

49. The Laplace transform of sin t is

a. 2 2s

s

b. 22 2s

c. 2

2 2

ss

d. 2 2s

50. Given, f (t ) =0

( ) ( ) .st F s f t e dt which

of the following expressions are correct?1. ( ) ( ) ( ) sa f t a u t a F s e

2. ( )( ) dF s

tf t ds

3. ( ) ( ) ( )t a f t as F s

4. ( ) ( ) (0 )df t

s F s f dt

Select the correct answer using the codesgiven below:a. 1, 2 and 3 b. 1, 2 and 4



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7 of 15c. 2, 3 and 4d. 1, 3 and 4

51. Two rectangular waveforms of duration T1 and T2 seconds are convolved. What is theshape of the resulting waveform?a. Triangular

b. Rectangularc. Trapezoidald. Semi-circular

52. A discrete LTI system is non-causal if itsimpulse response isa. an u(n 2)

b. an2 u(n)c. an+2 u(n)d. an u(n + 2)

53.

In the circuit shown above, the voltageacross 2 resistor is 20 V. The 5 resistorconnected between the terminals A and Bcan be replaced by an ideala. Voltage source of 25 V with + terminal

upward b. Voltage source of 25 V with + terminal

downwardc. Current source of 2 A upwardd. Current source of 2 A downward

54.

The current flowing through the voltagesource in the above circuit isa. 1.0 A

b. 0.75 Ac. 0.5 Ad. 0.25 A

55. The number of edges in a compete graphof n vertices isa. n(n 1)

b. ( 1)2

n n

c. n d. n 1

56.

In the above circuit, if |l1| = |l2| = 10 Aa. l1 will lead by tan 1 8/6, l2 will lag by

tan 1 8/6 b. l1 will lead by tan 1 6/8, l2 will lag by

tan 1 6/8c. l1 will lead by tan 1 8/6, l2 will lag by

tan 1 8/6

d. l1 will lead by tan 1

6/8, l2 will lag bytan 1 6/857. A two port network is reciprocal, if and

only ifa. Z11 = Z22 b. BC AD = 1c. Y12 = Y21 d. h12 = h21

58.

In the circuit shown above, the switch isclosed at. t = 0. The current through thecapacitor will decrease exponentially witha time constanta. 0.5 s b. 1 sc. 2 sd. 10 s

59.



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8 of 15In the circuit shown above, the switch ismoved from position A to B at time t = 0.The current i through the inductor satisfiesthe following conditions1. i(0) = 8A2. di/dt (t = 0) = 3A/s3. I( ) = 4AThe value of R isa. 0.5 ohm

b. 2.0 ohmc. 4.0 ohmd. 12 ohm

60. In a circuit the voltage across an element isv(t) = 10(t 0.01 )e 100t V. The circuit isa. Undamped

b. Under dampedc. Critically dampedd. Over damped

61.

1.

2.

3.

4.

The correct sequence of the time constantsof the circuits shown above in theincreasing order isa. 1 2 3 4

b. 4 1 2 3

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

62.

An iron-cored choke of large inductance isconnected to a d.c. supply as shown in theabove circuit. A capacitor C is alsoconnected across the switch. The role of Cis toa. Improve the power factor of the circuit b. Minimize the current drawn from

supplyc. Prevent the arcing across switching

under switching conditionsd. Increase the magnetic flux in the core

63. Bartletts bisection theorem holds forwhich one of the following terminalnetworks?a. Reciprocal network b. Balanced networkc. Symmetric networkd. Non-linear network

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

List IA. Internal impedance of an. ideal current

source isB. For attenuated natural oscillations, the

poles of the transfer function must lieon the

C. A battery with an e.m.f. E and internalresistance R delivers current to a loadR L. Maximum power transferred is

D. The roots of the characteristic equationgive

List II1. Forced response of the circuit2. Natural response of the circuit3. E2/4R4. E2/2R5. Left hand part of the complex

frequency plane6. Right hand part of the complex

frequency plane



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9 of 157. Infinite8. Zero.

A B C Da. 7 6 3 1

b. 8 5 4 2c. 8 6 4 1

d.

7 5 3 265.

In Maxwell bridge as shown above, thevalue of C and its shunting resistance R 1 are unknown. The bridge balance relationsare Z1/Z3 = Z2/Z4. The values of C and R 1 area. C = L/R 2R 3, R 1 = R 2R 3/R 4

b. C = L/R 3R 4, R 1 = R 4/R 2R 3 c. C = LR 2/R 3, R 1 = R 3/R 2R 4 d. C = LR 3/R 2, R 1 = R 3/R 2R 4

66. In the pass-band of a symmetric latticefilter, the nature of XA and XB, where XA and XB represent the reactances of theseries, arm and the diagonal arm of the

lattice is ofa. The same sign b. The opposite signc. The same sign and equal magnituded. Of arbitrary sign

67. Match List I (Quantities) with List II(Units) and select the correct answer :List IA. R/LB. 1/ LC

C. CRD. L/CList II1. Second2. Ohm3. (Radian/Second)2 4. (Second) 1

A B C Da. 4 3 1 2

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

68. An electric charge Q is placed in adielectric medium. Which of the followingquantities are independent of the dielectricconstant of the medium ?a. Electric potential V and Electric field

intensity E b. Displacement density D and

Displacement c. Electric field intensity E and

Displacement density Dd. Electric potential V and Displacement

69. Two coaxial cylindrical sheets of charge

are present in free space, s = 5 C/m2 at r =

2 m and s = 2 C/m2

at r = 4 m. Thedisplacement flux density D at r = 3 m is

a. 2D 5a /r C m

b. 2D 2 / 3a /r C m

c. 2D 10 / 3a /r C m

d. 2D 18 / 3a /r C m 70. Two thin parallel wires are carrying

current along the same direction. The forceexperienced by one due to the other isa. Parallel to the lines b. Perpendicular to the lines and

attractivec. Perpendicular to the lines and repulsived. Zero

71. An electric potential field is produced inair by point charges 1 C and 4 C locatedat (2, 1, 5) and (1, 3, 1) respectively.The energy stored in the field isa. 2.57 mJ b. 5.14 mJc. 10.28 mJd. 12.50 mJ

72. Which one of the following potentials does NOT satisfy Laplaces Equation ?a. V = 10 xy b. V = r cos c. V = 10/rd. V = cos + 10

73. Laplacian of a scalar function V is



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b. Divergence of Vc. Gradient of the gradient of Vd. Divergence of the gradient of V

74. Match List I (Dominant Mode ofPropagation) with List II (Type ofTransmission Structure) and select thecorrect answer:List IA. Coaxial lineB. Rectangular waveguideC. Microstrip lineD. Coplanar waveguideList II1. TE2. Quasi TEM3. Hybrid4. TEM

A B C Da. 1 4 2 3

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

75. In a line the VSWR of a load is 6 dB. Thereflection coefficient Will bea. 0.033

b.

0:33c. 0.66d. 3.3

76. ZL = 200 and it is desired that Zi = 50 .The quarterwave transformer should havea characteristic impedance ofa. 100

b. 40 c. 10,000 d. 4

77. A TEM wave impinges obliquely on adielectric- dielectric boundary ( r 1 = 2, r 2 = 1). The angle of incidence for totalreflection isa. 30

b. 45c. 60d. 75

78. A plane electromagnetic wave travelling ina perfect dielectric medium of

characteristic impedance 1 is incidentnormally on its boundary with another perfect dielectric medium of characteristicimpedance 2. The electric and magneticfield strengths of the incident wave aredenoted. by Ei and Hi respectively whereasEr and Hr denote these quantities for the

reflected wave, and Et and Ht for thetransmitted wave.Which of the following relations arecorrect ?1. Ei = 1Hi 2. Er = 1Hr 3. Et = 2Ht Select the correct answer using the codesgiven below:a. 1, 2 and 3 b. 1 and 2c. 1 and 3d. 2 and 3

79. A plane electromagnetic wave travelling ina perfect dielectric medium of dielectricconstant 1 is incident on its boundarywith another perfect dielectric medium ofdielectric constant 2. The incident raymakes an angle of 1 with the normal tothe boundary surface. The ray transmittedinto the other medium makes an angle of

2 with the normal. If 1 = 2 1 and 1 =600 , which one of the following is correct?a. 2 = 450 b. 2 = sin 1 0.433c. 2 = sin 1 0.612d. There will be no transmitted wave

80. In a. four element Yagi-Uda antennaa. There is one driven element, one

director and two reflectors b. There is one driven element, two

directors and one reflectorc. There are two driven elements, onedirector and two reflectors

d. All the four elements are drivenelements

81. Which one of the following Maxwellsequations gives the basic idea of radiation?

a. //

H D t

E B t



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b. /

. 0 E B t

D

c. .. 0 D

B

d. . 0

( / ) B

H D t

82. For TE or TM modes of propagation in bounded media, the phase velocitya. Is independent of frequency

b. Is a linear function of frequencyc. Is a non-linear function of frequencyd. Can be frequency-dependent or

frequency independent depending onthe source

83. A waveguide operated below cut-offfrequency can be used asa. A phase shifter

b. An attenuatorc. An isolatord. None of the above

84. Match List I (Nature of Polarization) withList II (Relationship Between X and YComponents) for a propagating wavehaving cross-section in the XY plane and

propagating along Z-direction and selectthe correct answer :

List IA. LinearB. Left circularC. Right circularD. EllipticalList II1. X and Y components are in same phase2. X and Y components have arbitrary

phase difference3. X component leads Y by 900

4. X component lags behind Y by 90A B C D

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

85. An air condenser of capacitance of 0.005F is connected to a d.c. supply of 500

Volts, disconnected and then immersed inoil with a dielectric constant of 2.5. Energy

stored in the capacitor before and afterimmersion, respectively isa. 500 10 4 Joules and 250 10 4 Joules b. 250 10 4 Joules and 500 10 4 Joulesc. 625 10 4 Joules and 250 10 4 Joulesd. 250 10 4 Joules and 625 10 4 Joules

86.

Consider the following data for the circuitshown above :Ammeter : Resistance 0.2 Reading 5.0AVoltmeter : Resistance 2k Reading 200VWattmeter : Current coil resistance 0.2 ,

Pressure coil resistance 2 k Load : Power factor = 1The reading of the Wattmeter isa. 980 W b. 1000 Wc. 1005 Wd. 1010 W

87. Force developed by an electromagnet isgiven asF = aB bAc

where = permeability of air in the gapB = flux density in the air gapA = cross-sectional area of the gap

Then a, the values of b and c arerespectivelya. 1, 1 and 2 b. 1, 1 and 2

c. 1, 2 and 1d. 1, 2 and 1

88.



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12 of 15Consider the circuit as shown above. Z1 isan unknown impedance and measured asZ1 = (Z2Z3)/Z4. The uncertainties in thevalue of Z2, Z3 and Z4 are 1%, 1% and3% respectively. The overall uncertaintyin the measured value of Z1 is

a. 11%

b. 4%c. 5%

d. 5%89. The measured value of a capacitor is

100 F. The true value of the capacitor is110 F. The percentage relative error isa. 9.99%

b. 9.09%c. 10.0%d. 4.76%

90. The X and Y inputs to a CRC arerespectively 10 cos (100 t + ) and 10 sin(100 t + ). The resulting Lissajous patternisa. A straight line inclined at an angle

b. A horizontal linec. An ellipse with axis making an angle d. A circle

91. For the measurement of the voltage of theorder of mV, the voltmeter used isa. Rectifier-amplifier type VTVM

b. Amplifier-rectifier type VTVM.c. Diode peak reading voltmeterd. Slide wire VTVM

92. Wagners earthing device is used in a.c. bridges for eliminating the effect ofa. Stray electrostatic field

b. Intercomponent capacitancesc. Earth capacitanced. All the above three

93.

For the Owen-bridge circuit shown above,when balanced, the values of L and R area. L = CSR S / R 1, R = R SCS/C1 b. L = CSR S R 1, R = R SCS/C1 c. L = C1R SR 1, R = R SCSC1 d. L = CS/C1 R SR 1, R = R 1CS/C1

94. Match List I with List II and select thecorrect answer:List I (Instrument)A. Vibration GalvanometerB. Head phoneC. DArsonval GalvanometerD. C.R.C.List II (Frequency)1. 100 Hz2. Zero Hz

3.

1 kHz4. Large frequency rangeA B C D

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

95. Consider the following statements :1. A variable capacitance type transducer,

gives an output proportional to

acceleration2. LVDT is a self-governing type oftransducer.

3. Eddy current type of transducer givesan output proportional to velocity

4. A piezoelectric transducer cannot beused to measure static variables

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

96. A temperature between 200C and1000C may be measured conveniently bya. Thermistor b. Resistance thermometerc. Optical pyrometerd. Copper-constantan thermocouple

97. A hot-wire anemometer is a device used tomeasure



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14 of 15a. Both A and R are individually true and

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

R is not the correct explanation of Ac. A is true but R is falsed. A is false but R is true

107. Assertion (A) : The conductivity of asemiconductor is decided by the level ofits doping and is almost independent of its

band gap value irrespective oftemperature.Reason (R) : The carrier concentration dueto doping is independent of temperature, ifit is not too low.a. Both A and R are individually true and



108. Assertion (A) : In a transistor the thicknessof the base region is kept as small as

possible.Reason (R) : By keeping the basethickness small, a large electric field is

produced between the emitter and thecollector which makes the transistor fast-acting.a. Both A and R are individually true and



109. Assertion (A) : A drift transistor exhibits better high-frequency response ascompared to a diffusion transistor, when

both the transistors have identical base,collector and emitter geometries.

Reason (R) : The transport of minoritycarriers in the base region of a drifttransistor is by the drift process, whereasthat in a diffusion transistor is by thediffusion process.a. Both A and R are individually true and



110. Assertion (A) : A periodic functionsatisfying Dirichlet conditions can beexpanded into Fourier series.Reason (R) : A periodic function can be

reconstructed from 0 01

cos2 nna

a n t

01

sinnn

b n t for very lage n, excluding

infinity.a. Both A and R are individually true and



111. Assertion (A) : In the exponential Fourierrepresentation of a real-valued periodicfunction f (t) of frequency f 0, thecoefficients of the terms 02 j nf t e and

02 j nf t e are negatives of each other.Reason (R) : The discrete magnitudespectrum of f (t) is even and the phasespectrum is odd.a. Both A and R are individually true and


R is not the correct explanation of Ac. A is true but R is false

d. A is false but R is true112. Assertion (A) : Kirchoffs voltage law

states that in a closed path in a network,the algebraic sum of all voltages in asingle direction is zero.Reason (R) : Law of conservation ofcharge is the basis of this law.a. Both A and R are individually true and



113. Assertion (A) : Superposition theorem isused to particular branch in a linearnetwork calculate the current in a of eachof the independent sources, by consideringthe effect taken one-at a time.Reason (R) : In a linear network, the behaviour of the circuit does not varydepending upon the source.



15/15

15 of 15a. Both A and R are individually true and



114. Assertion (A) : Maximum power transferfrom a source with complex internalimpedance to a complex load will occur ifthe source impedance is same as the loadimpedance.Reason (R) : The efficiency of maximum

power transfer cannot exceed 50%.a. Both A and R are individually true and



115. Assertion (A) : The current in a series R-L-C circuit driven by a sinusoidal voltagesource may lead, lag or be in phase withthe applied voltage.Reason (R) : Series resonance does notimply unity power factor condition.a. Both A and R are individually true and



116. Assertion (A) : A two-terminal networkrepresenting a given driving pointreactance function is said to be a canonicor a fundamental network.Reason (R) : A driving point reactancefunction is totally specified by the locationof poles and zeros.a. Both A and R are individually true and



117. Assertion (A) : For extremely highfrequency ranges or above, compared tolinear antennas, aperture antennas aremore useful.

Reason (R) : The larger the effective areaof an antenna, the sharper is the radiated beam.a. Both A and R are individually true and


R is not the correct explanation of A

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

118. Assertion (A) : The quality factor Q of awaveguide is closely related to itsattenuation factor .Reason (R) : Normally attenuation factorsobtainable in waveguides are much higherthan those obtainable in transmission lines.a. Both A and R are individually true and



119. Assertion (A) : A VTVM is preferred to anordinary multimeter for measurement ofvoltages in an electronic circuit.Reason (R) : A VTVM has built-inamplifier and it gives very accurate results.a. Both A and R are individually true and

R is the correct explanation of A

b. Both A and R are individually true butR is not the correct explanation of A

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

120. Assertion (A) : Operational amplifiers arecommonly used in instrumentation.Reason (R) : The operational amplifiers donot load the circuit due to their very highinput impedance.a. Both A and R are individually true and




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IES OBJ Electronics &Telecomm.I 2003