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Detailed SolutionSET - A

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1. A white noise of magnitude 0.001 µW/Hz isapplied to an RC low pass filter of R = 1kand C = 0.1 F .The output noise power of theRC low-pass filter is

(a) 0.5 W (b) 1.5 W

(c) 2.5 W (d) 3.5 W

Ans. (c)

Sol. Given: R = kC = 0.10 µF

Outpout noise power = 0N4RC

=

–6

3 –60.001 10

10 0.1 10 = 2.5 µW

2. The two random variables X and Y areuncorrelated if and only if their covariance is

(a) 0 (b) 1

(c) –1 (d) infinity

Ans. (a)

Sol. The correlation coefficient =

xy

x y.

xy = 0

3. The antenna current of an AM transmitter is8 A when only the carrier signal is transmit-ted. What is the antenna current when thecarrier signal is modulated by sinusoidal sig-nal V t =1.4sin 2 ×500t with modulationindex 0.8 ?

(a) 3.2A (b) 7.2A

(c) 9.2A (d) 11.2A

Ans. (c)

Sol. We know that

It = 2

CI 1+2

It =2(0.8)8 1+

2

= 9.2A

4. A 10 MHz carrier signal is frequency modu-lated by analog-modulating signal. The maxi-mum frequency deviation is 75 kHz. If thefrequency of the modulating signal is 300 kHz,then the modulation index and the approxi-mate transmission bandwidth of the FM sig-nal are respectively,

(a) 0.25, 750 kHz (b) 0.25, 600 kHz

(c) 0.75, 750 kHz (d) 0.75, 450 kHz

Ans. (b)

Sol. The modulation index ( ) =

m

ff =

3

375 10300 10

= 0.25

As 1 Narrow band frequency modulation

B.W 2fm

= 2 × 300 × 103

= 600 kHz

5. Consider the fol lowing statements forbaseband transmission model

1. Channel signal-to-noise ratio is defined as theratio of the average power of the modulatedsignal to the average power of noise in themessage bandwidth, both measured at thereceiver input.

2. Channel signal-to-noise ratio is defined as theratio of the average power of the modulatedsignal to the average power of noise in themessage bandwidth, both measured at the re-ceiver output.

3. Figure of merit =

o

c

SNRSNR , where ‘o’ stands

for output and ‘c’ stands for channel.

4. Figure of merit =

c

o

SNRSNR , where ‘o’ stands

for output and ‘c’ stands for channel.

Which of the above statements are correct ?

(a) 1 and 3 only (b) 2 and 3 only

(c) 1 and 4 only (d) 2 and 4 only

Ans. (a)

Sol.





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6. What is the entropy of a communication sys-tem that consists of six messages with prob-abilities 1/8, 1/8, 1/8, 1/8, 1/4 and 1/4 respec-tively.

(a) 1 bit/message (b) 2.5 bits/message

(c) 3 bit/message (d) 4.5 bits/message

Ans. (b)

Sol. Entropy = n

i 2ii =1

1p(x ) logp(x )

= 1 14 log 8 + 2 log 48 4

= 2.5 bits/message

7. Discrete samples of an analog signal areuniformly quantised to PCM. If the maximumvalue of analog sample is to be representedwithin 0.1% accuracy, then the minimum num-ber of binary digits required per sample is

(a) 4 (b) 8

(c) 10 (d) 12

Ans. (c)

Sol.2

0.1100

Am

mn

2 A2 2

m0.1 A100

n 10

8. Six analog information signals, each band-limited to 4 kHz, are required to be time-divi-sion multiplexed and transmitted by a TDMsystem. The minimum transmission bandwidthand the signalling rate of the PAM/TDM chan-nel are respectively,

(a) 24 kHz and 48 kbps

(b) 24 kHz and 8 kbps

(c) 48 kHz and 48 kbps

(d) 48 kHz and 16 kbps

Ans. (a)

Sol. Bit rate Rb = sN n f

= 6 1 8k

= 48 kbps

and BW = bR = 24 kHz2

9. A 2000 bps binary information data signal isrequired to be transmitted in half-duplex modeusing BFSK digital modulation technique. Ifthe separation between two carrier frequen-cies is 4000 Hz, then the minimum bandwidthof the BFSK signal is

(a) 4 kHz (b) 6 kHz

(c) 8 kHz (d) 12 kHz

Ans. (b)

Sol. (B.W)min = Rb + fH – f2

= 2000 + 4000= 6 kHz

10. If voice activity interference reduction factoris 2.5, antenna sectorization gain factor is 2.5and interference increase factor is 1.6, thenthe performance improvement factor in CDMAdigital cellular system is

(a) 1.2 (b) 2.5

(c) 3.1 (d) 3.9

Ans. (d)

Sol. pf = A rG G 2.5 2.5=P 1.6

= 3.9

11. The temperature at a particular place variesbetween 14°C and 34°C. For the purpose oftransmitting the temperature record of thatplace using PCM, the record is sampled at anappropriate sampling rate and the samplesare quantized. If the error in representation ofthe samples due to quantization is not toexceed ±1% of the dynamic range, what isthe minimum number of quantization levelsthat can be used?

(a) 100 (b) 50

(c) 30 (d) 15

Ans. (b)

Sol.2 m

1 2 A100





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m2A2 L m

1 2 A100

L 50

12. A multimnode step index fiber with a corediameter of 80 m and a relative index differ-ence of 1.5% is operating at a wavelength of0.85 m . If the core refractive index is 1.48,then the normalized frequency for the fiber is

(a) 37.9 (b) 75.8

(c) 151.6 (d) 303.2

Ans. (b)

Sol. V =2 a .NA

V =

–6

–62 40 10 1.48 2 (1.5 / 100)

0.85 10

V = 75.8

13. The even and odd components of the signal

–2tx t = e cos t are respectively,,

(a) cos2tcos t and – sin2tcos t

(b) sin2tsin t and – cosh2tcos t

(c) cos2t sin t and – sin2tcos t

(d) cosh2tcos t and – sinh2tcos t

Ans. (d)

Sol. Even part = x(t) + x (–t)

2

=–2t 2te cost + e cost

2= cos(h) 2t.cos t

Odd part = x t – x –t

2

=–2t 2te cost – e cost

2= –sin(h) 2t cos t

14. What is the convolution integral c(t) for asystem with input x(t) and impulse responseh(t) where x(t) = u(t – 1) –u(t – 3) and h(t) =

u(t) – u(t – 2) ?

(a)

0, t 1t – 1, 1 t 3

c t =5 – t, 3 t 5

0, t 5

(b)

0, t 11t – , 1 t 22c t =

3 – t, 2 t 52

0, t 5

(c) 0, t 1

c t = 5 – t, 1 t 40, t 4

(d) 2, 1 t 2

c t = 1, 3 t 50, otherwise

Ans. (a)

Sol. Given : x(t) = u(t – 1) – u(t – 3)h(t) = u(t) – u(t – 2)y(t) = x(t) * h(t)= [u(t – 1) – u(t – 3)] * [u(t) – u(t – 2)]= r(t – 1) – r(t – 3) – r(t – 3) + r(t – 5)

=

0, t 1t – 1, 1 t 35 – t, 3 t 50, t 5

15. The power and energy of the unit step se-quence are respectively,

(a) 1/2 and 0 (b) 1/2 and infinity

(c) 2 and 0 (d) 2 and infinity

Ans. (b)

Sol. For power signal, energy =

Power = N

2

nn=–N

1 1lim x n =2N +1 2

16. Which one of the following is correct for thegiven system ?

y n = x n – x n – 1





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(a) Time invariant and causal

(b) Time variant and non-causal

(c) Time variant and causal

(d) Time invariant and non-causal

Ans. (a)

Sol. Time invariant and causal

17. Two vectors V1 and V2 are orthogonal if thisdot product is

(a) 1 (b) 0

(c) infinity (d) 0.5

Ans. (b)

Sol. V1.V2 = 0 for orthogonal

18. A discretet-time LTI system with rational sys-tem function H(z) is causal if and only if

(a) the ROC is the exterior of a circle outside theoutermost pole.

(b) the ROC is the interior of a circle outside theoutermost pole

(c) the ROC is the exterior of a circle outside theinnermost pole

(d) the ROC is the interior of a circle outside theinnermost pole.

Ans. (a)

Sol. The ROC is exterior of a circle outside the out-ermost pole.

19. A feedback system has an open-loop transferfunction of

G s H s =

2K 1– s

s s + 5s + 9

By using the Routh criterion, the maximumvalue of K for the closed-loop system to bestable is

(a) 2.5 (b) 5

(c) 7.5 (d) 9

Ans. (c)

Sol. The characteristic equation : 1 + G(s)H(s) = 0

s3 + 5s2 + 9s – ks + k = 0

3

2

0

s 1 9 – k

s 5 ks 45 – 5k – k

s k45 – 5k – k > 06k < 45

k 7.5

20. The steady-state error of type 1 system with

input 2tr t = , t 02

; is

(a) 0 (b) 1/2

(c) 1 (d)

Ans. (d)

Sol. For r(t) = 2t2

Ka = 2

s 0lim s G(s)H(s)

For type-1 system:Ka = 0

ess = a

1 1=K 0

sse =

21. Which one of the following statements cor-rect regarding constant N circles ?

(a) The locus of constant, closed-loop magnitudefrequency response for unity feedback sys-tems.

(b) The locus of constant, closed-loop phase fre-quency response for unity feedback systems.

(c) A subsystem inserted into the forward or feed-back path for the purpose of improving thetransient response or steady-state error.

(d) A system that monitors its output and correctsfor disturbances. It is characterized by feed-back paths from the output.

Ans. (b)

Sol.





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22. Which one of the following digital modulationschemes has the bi t error rate as

b

o

E1 erfc2 N

?

(a) Coherent binary PSK

(b) Coherent binary FSK

(c) DPSK

(d) Non-coherent binary FSK

Ans. (a)

Sol. For coherent PSK :

BER = b b

o o

2E E1Q = erfcN 2 N

23. Which one of the following conditions is jus-tifying a second-order approximation ?

(a) Closed-loop zero near the closed-loop sec-ond-order pole pair are nearly cancelled bythe close proximity of higher-order closed-looppoles.

(b) Closed-loop zeros cancelled by the closeproximity of higher-order closed-loop polesare far removed from the closed-loop second-order pole pair.

(c) Closed-loop zeros near the closed-loop sec-ond-order pole pair are not cancelled by theclose proximity of higher-order closed-looppoles.

(d) Closed-loop cancelled by the close proximityof higher-order closed-loop poles are far re-moved from the closed-loop second-orderzero pair.

Ans. (c)

Sol.

24. Consider the following statements regardingthe disadvantages of a passive lead networkover an active PD controller :

1. No additional power supplies are required.

2. Noise due to differentiation is reduced.

3. Additional pole does not reduce the numberof branches of the root locus that cross theimaginary axis into the right half plane.

4. Addition of the single zero of the PD control-ler tends to reduce the number of branchesof the root locus that cross into the right half-plane.

Which of the above statements is/are correct ?

(a) 1 only (b) 2 only

(c) 3 and 4 only (d) 1, 2 and 4 only

Ans. (c)

Sol.

25. Which one of the following characteristics iscorrect regarding RISC processor ?

(a) Relatively very large addressing modes

(b) Multi-cycle instruction execution

(c) All operations are not done within the regis-ters of the CPU

(d) Relatively few instructions

Ans. (d)

Sol. RISK process have relatively few instruction.

26. Which one of the following instructions in astack computer consists of an operation codeonly with no address field ?

(a) PUSH X (b) POP X

(c) ADD (d) LOAD A

Ans. (c)

Sol. ADD instruction does not have any address field.

27. Which one of the following statements is cor-rect regarding arithmetic and logical opera-tions ?

(a) When two 3-bit unsigned numbers are multi-plied, the result is an 8-bit product that mustbe stored in three memory words

(b) When two 16-bit unsigned numbers are mul-tiplied, the result is a 32-bit product that mustbe stored in two memory words.

(c) Operations that are implemented in a com-puter with one machine instruction are saidto be implemented by software.

(d) Operations implemented by a set of instruc-tions that constitute a program are said to beimplemented by hardware.





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Ans. (b)

Sol. n bits multiply with n bits = 2n bits

28. Which one of the following techniques inher-its the simplicity of the direct mapping tech-nique in terms of determining the target set ?

(a) Set-associative-mapping technique

(b) Set-associative-direct mapping technique

(c) Direct mapping set technique

(d) Indirect mapping set technique

Ans. (a)

Sol.

29. Which one of the following memories is pri-marily used to store machine microcode, desk-top bootstrap loaders, and video game car-tridges ?

(a) Mask-programmed ROM

(b) Static-RAM

(c) Dynamic-RAM

(d) Non-Programmed ROM

Ans. (a)

Sol.

30. In which one of the following situations is theCPU often idle ?

(a) The speeds of the mechanical I/O devices areintrinsically slow than those of electronic de-vices.

(b) The speeds of the electromechanical I/O de-vices are intrinsically faster than those of elec-tronic devices.

(c) The speeds of the electrical I/O devices areintrinsically slower than those of electronicdevices.

(d) The speeds of the electrical I/O devices areintrinsically faster than those of electronicdevices.

Ans. (a)

Sol.

31. Which one of the following system provides amechanism for translating program-generatedaddressing into correct main memory loca-tions ?

(a) Virtual memory system

(b) Main memory system

(c) Physical address system

(d) Memory space system

Ans. (a)

Sol. Virtual memory system provides a mechanismfor translating the logical address into a physicaladdress.

32. Consider the following statements regardingmemory :

1. Integrated circuit RAM chips are available inboth static and dynamic modes.

2. The dynamic RAM stores the binary informa-tion in the form of electric charges that areapplied to capacitors.

3. The static RAM is easier to use and hasshorter read and write cycles.

4. RAM and ROM chips are available in a vari-ety of sizes.


(a) 1 and 2 only (b) 1, 3 and 4 only

(c) 2, 3 and 4 only (d) 1, 2, 3 and 4

Ans. (d)

Sol.

33. Which one of the following messaging sys-tems attempts to avoid double copy opera-tions by using virtual-memory managementtechniques ?

(a) Mach message system

(b) Duplex message system

(c) Packet message system

(d) Data message system

Ans. (a)

Sol. Mach message system attempts to avoid doublecopy operations by using virtual-memory man-agement techniques.

34. Which one of the following storage devicesused is when the operating system abstractsfrom the physical properties of its storagedevices to define a logical storage unit ?

https://iesmaster.org/ese-mains-conventional-question-practice-program





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(a) Volatile storage devices

(b) Nonvolatile devices

(c) Flash storage

(d) Cache storage devices

Ans. (b)

Sol.

35. Which one of the following is not correct whenwe define either a class that does not imple-ment either a mathematical entity like a ma-trix or a complex number or a low-level typesuch as linked list?

(a) Don’t use global data (use members)

(b) Don’t use local functions

(c) Don’t use public data members

(d) Don’t use in-line functions, except as a sig-nificance optimization.

Ans. (d)

Sol. Complior may not perform inlining.

36. Which one of the following is also called aspseudo instructions that are not directly trans-lated into machine language instruction?

(a) Macro expansions

(b) Assembly directives

(c) Micro expansions

(d) Labels

Ans. (b)

Sol.

37. The component of x zˆ ˆP = 2a – a

along

x y zˆ ˆ ˆQ = 2a – a + 2a

is

(a) x y zˆ ˆ ˆ0.745a + 0.298a – 0.596a

(b) x y zˆ ˆ ˆ4a – 2a + 4a

(c) x y zˆ ˆ ˆ0.2222a – 0.1111a + 0.2222a

(d) x y zˆ ˆ ˆ0.4444a – 0.2222a + 0.4444a

Ans. (d)

Sol. Given : x zˆ ˆP = 2a – a

Component of P along Q

= QˆP Q a

= x z x y z

x y z

2 1 2ˆ ˆ ˆ ˆ ˆ2a – a a – a + a3 3 3

2 1 2ˆ ˆ â – a + a3 3 3

= x y zˆ ˆ ˆ0.44a – 0.222a + 0.44a

38. Consider the following equations with timefactor j te

1. S vsD .dS = dv 2. S SE .d = –j B l

3. SB .dS = 04. S S SH .dS = J + j D .d l

Which of the above Time-Harmonic Maxwell’sequations are correct ?


(c) 1, 2 and 3 only (d) 3 and 4 only

Ans. (b)

Sol. s sE d = – j B l

39. ˆ Â = cos a + sin a

, then the surface inte-

gration of curl of A (for 30 60 and

2 5 ) is

(a) 6.750 (b) 4.941

(c) 0.732 (d) 1.765

Ans. (b)

Sol. Given : ˆ Â = cos a + sin a

zˆds = d d a

1A ds = sin d d + sin d d

5 /3 5 /3

=2 = /6 =2 = /6

d sin d + d sin d

52

2 /3 /35 = /6 /6

=2– cos + – cos

2

= 4.941





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40. Which one of the following is not the basicrule for boundary conditions at the surfacebetween two different materials ?

(a) The tangential components of electric fieldintensity are continuous across the boundary.

(b) The normal components of electric flux den-sity are discontinuous at the boundary by anamount equal to the surface-charge densityon the boundary.

(c) The tangential components of magnetic fieldintensity are discontinuous at the boundaryby an amount equal to the surface-currentdensity on the boundary.

(d) The normal components of electric field in-tensity are continuous across the boundary.

Ans. (d)

Sol. 2 1n n sD – D =

41. A uniform plane wave propagating in a me-dium has

– z 8yÊ = 2e sin 10 t – z a V m

if the medium is characterized by r =1 ,

r = 20 and = 3S m . The values of and are respectively..

(a) 30.70 Np/m, 30.70 rad/m

(b) 61.40 Np/m, 61.40 rad/m

(c) 122.80 Np/m, 122.80 rad/m

(d) 15.35 Np/m, 15.35 rad/m

Ans. (b)

Sol. As 1

= =2

= 8 –710 × 4 ×10 ×3× 20

2

= 61.40 NP/m, 61.40 rad/m

42. A distortionless transmission line has the fol-lowing parameters :

Characteristic impedance = 60 , wave ve-locity = 0.6c, where c is the speed of light ina vacuum, = 20 mNp/m. The value of trans-

mission line parameters R, L, G and C at 100MHz are respectively.

(a) 1.2 m, 333nH m, 333 S m, 92.59pF m

(b) 1.2 m, 111H m, 333 S m, 92.59F m

(c) 2.4 m, 333nH m, 333 S m, 92.59F m

(d) 2.4 m, 111H m, 333S m, 92.59pF m

Ans. (a)

Sol. As o PL 1Z = , V = , = RGC LC

and = LC

C = –12

o P

1 = 92.59 ×10 F / mZ V

2oZ =

2o

L L = Z – CC

L = 333.224 nH/m

Zo = R

R = 20 × 10–3 × 60 = 1.2 A/m

G = oZ

G = 333 × 10–6 / m

43. Consider the following statements regardingthe Smith’s chart :

1. Smith’s chart is a graphical indication of theimpedance of a transmission line and of thecorresponding reflection coefficient as onemoves along the line.

2. distance on the line corresponds to a 720°movement on the Smith’s chart.

3. The admittance chart can be obtained by shift-ing each and every point on the impedancechart by 90°.

4. Counter -clockwise movement on the chartcorresponds to moving towards the genera-tor.



(c) 1, 2 and 4 only (d) 2, 3 and 4 only

Ans. (a)





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Sol. Counter clockwise movement on the chart cor-responds to moving towards to load.

44. Consider the following statements regardingthe load matching and impedance measure-ments ?

1. A mismatched load can be properly matchedto a line by inserting prior to the load a trans-mission line 4 long.

2. For matching of 120 load to 75 line, thequarter-wave transformer must have a char-acteristics impedance of 190 .

3. The main disadvantage of single-stub match-ing is that it is a narrow-band or frequency-sensitive device.

Which of the above statements are not cor-rect ?


(c) 1 and 3 only (d) 1, 2 and 3

Ans. (a)

Sol. Single-stub matching device is narrow-band orfrequency-sensitive device.

45. Which of the following antennas are useddirectly as radiators abroad satellites to illu-minate comparatively large areas of the Earthand they are widely used as primary feeds forreflector-type antennas both in transmittingand receiving modes ?

(a) Dipole antennas

(b) End fire-array antennas

(c) Microstrip antennas

(d) Horn antennas

Ans. (d)

Sol. Horn antenna is used as primary antenna.

46. At the higher frequencies, which one of thefollowing becomes more confined to the re-gion between the micro-strip and ground plane?

(a) Electric field (b) Magnetic field

(c) Dispersion (d) Skin effect

Ans. (b)

Sol.

47. A magnetic field strength of 5 A m is re-quired at a point on = 2 , which is 2 kmfrom a half-wave dipole antenna in air. If theradiation resistance of the half-wave dipoleantenna is 73 , then the power radiated bythis antenna (neglecting the ohmic loss) is

(a) 72 mW (b) 144 mW

(c) 158 mW (d) 315 mW

Ans. (b)

Sol. H = oI cos cos

22 r sin

Io = H 2 r sin

cos cos2

Io = –6 3

35×10 ×2 ×2×10 ×sin18 = 20 ×10cos cos90

2

Prad = 22 –3o rad

1 1I R = × 20 ×10 ×732 2

= 144 mW

48. Consider the following statements regardingthe waveguides :

1. Cut-off frequency is the operating frequencybelow which attenuation occurs and abovewhich propagation takes place.

2. The dominant mode is the mode with the low-est cut-off wavelength.

3. The dominant mode in the rectangularwaveguide (for a> b) will be TE01.

Which of the above statements is/are notcorrect ?


(c) 2 and 3 only (d) 3 only

Ans. (c)

Sol. The dominant mode will be TE10 for (a > b)

49. Consider the following statements for Poly-Sideposition :

1. Poly-Si layer is used for gate electrode ofMOSFET because it has similar lattice con-stants with SiO2.





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2. Poly-Si layer used for gate electrode ofMOSFET for the better mechanical stabilitydue to different thermal expansion coeffi-cients.

3. In VLSI circuits, interconnects can be com-pleted in one or two metal levels.

4. Poly-Si is used for short interconnects.



(c) 1 and 4 only (d) 2, 3 and 4 only

Ans. (b)

Sol. Alluminium is used for inter-connections.

50. Consider the following statements regardingthe Read Only Memory (ROM).

1. The stored data is lost if the power is removed.

2. It consists of an address decoder with a inputlines and a programmable OR array with noutput lines.

3. The minterms are ORed through the program-mable switches which an be made ON or OFFto select a particular minterm. The program-mable switches can be implemented by ei-ther bipolar, CMOS, nMOS or pMOS tech-nologies.

4. Mask-programmed ROMs are used in theapplications where the system requires datato be stored and to be changed during theoperation.




Ans. (c)

Sol.

51. If each core in a 16-core processor has ayield of 90% and nothing else on the chipfails, what is the yield of the chip ?

(a) (0.9)8 (b) (0.9)16

(c) (0.1)8 (d) (0.1)16

Ans. (b)

Sol. Yield of chip = (0.9)16

52. What is the simplified value of y(n), if

5

n=–5y n = sin 2n n + 7 ?

(a) sin 10 (b) –sin 10

(c) 1 (d) 0

Ans. (d)

Sol. y(n) = 5

n=–5

sin 2n n + 7 Since, n = –7 outside –5 to 5Therefore, y(n) = 0

53. The energy of the signal nx n = –0.4 u n is

(a) 1/16 (b) 1/36

(c) 5/3 (d) 25/4

Ans. (*)

Sol. E = 1

1– 0.16 = 2521

54. Consider the following statements for a sys-tem given by

k=–

y n = x n n – 3k .

1. The system is linear

2. The system is non-linear

3. The system is causal

4. The system is non-causal


(a) 1 only (b) 2 only

(c) 2 and 4 only (d) 1 and 3 only

Ans. (d)

Sol. Linear and Causal

55. Which one of the following is the zero-inputresponse of the system.

y[n] – 3y[n – 1] – 4y [n – 2] = 0

described by the homogeneous second-orderdifference equation if y[–2] = 0 and y[–1] = 5?

(a) yzi(n) = (–1)n+1 + (–4)n+2, n 0

(b) n+1 n+2ziy n = 1 + 4 , n 0





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(c) n+1 n+2ziy n = 1– + 4 , n 0

(d) n+1 n+2ziy n = 1 + –4 , n 0

Ans. (c)

Sol. Applying unilateral z-transform,Y(Z) – 3[z–1Y(z) + y(–1)] – 4[z–2Y(z)

+ z–1y(–1) + y(–2)] = 0

Y(z) = –1

–1 –215 + 20z

1– 3z – 4z

y(n) = –(–1)n u(n) + 16(4)n u(n)

= [(–1)n+1 + (4)n+2]u(n)

56. Consider the following statements regardingEpitaxial Growth:

1. Thin layers are grown on a substrate wafer,this technique is known as epitaxial growth.

2. Physical vapour deposition is also calledvapour phase epitaxy.

3. OMCVD is a technique to grow epitaxial lay-ers from metalorganic compounds.

4. High throughout and slow deposition rate arethe disadvantages of the CVD technique.




Ans. (b)

Sol. Chemical vapour deposition is called vapourphase epitaxy.

57. FIR filter having anti-symmetrical impulseresponse with even filter order can be used isdesign.

(a) low-pass, high-pass, band-pass and band-stop

(b) low-pass and band-pass only

(c) high-pass and band-stop only

(d) differentiator and Hilbert transformer

Ans. (d)

Sol.

58. An IIR filter having numerator order M anddenominator order N is to be realized usingdirect form II structure. How much total num-

ber of multiplications, additions and memorylocations are required respectively ?

(a) M + N, M + N and M + N

(b) M + N, M + N and maximum of {M, N}

(c) M + N + 1, M + N + 1 and M + N

(d) M + N + 1, M + N and maximum of {M, N}

Ans. (d)

Sol.

59. In 8051, the accumulator register contains 80H and B register contains 8FH. The contentof the accumulator and status of the carryflag after the addition operation are respec-tively,

(a) 0FH, 1 (b) 10FH, 0

(c) FFH, 1 (d) 10FH, 1

Ans. (a)

Sol. A = 80H, B = 8 FH[A] + [B] = 10 FHAccumulator = 0FHCarry flag = 1H

60. Which one of the following operations is notcommutative?

(a) Scaling and reversal of a signal x[n]

(b) Scaling and folding of a signal x[n]

(c) Folding and time reversal of a signal x[n]

(d) Folding and time delaying of a signal x[n]

Ans. (d)

Sol.

61. Which one of the following traffics can adjust,over wide ranges, to changes in delay andthroughput across an internet and still meetthe needs of its applications?

(a) Elastic traffic (b) Inelastic traffic

(c) Internet traffic (d) Service traffic

Ans. (a)

Sol.

62. A data message of 10 ms duration having4800 bits crosses 9 nodes (10 hops) to reachits destination. The data rate and total delay





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for circuit switched connection (assuming nodedelays as 1 ms) are respectively,

(a) 240 kbps, 20 ms (b) 240 kbps, 21 ms

(c) 120 kbps, 21 ms (d) 480 kbps, 20 ms

Ans. (d)

Sol. Total delay = 10 + (10 × 1) = 20 ms

Data rate = 480010 = 480

63. Consider the following statements regardingthe OSI model:

1. Application layer provides the control struc-ture for communication between applications;establishes, manages and terminates connec-tions between cooperating applications.

2. Data link layer provides for the reliable trans-fer of information across the physical link.

3. Transport layer provides end-to-end error re-covery and flow control of data.

Which of the above statements are correct?


(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (d)

Sol. Session layer establishes, manages and termi-nates connections between cooperating applica-tions.

64. Consider the following statements regardingthe TCP/IP protocol:

1. TELNET is an application of TCP protocol.

2. SMTP provides a basic electronic mail facil-ity and makes use of TCP to send messageto an SMTP module on another host.

3. The internet Protocol is used at internet layerto provide the routing function across mul-tiple networks.


(a) 1 and 2 only (b) 1 and 3

(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (c)

Sol. SMTP uses UDP

65. If a cellular system has p number of co-chan-

nel interfering cells, S is the desired signalpower from serving base station and IP isinterference power from pth interfering co-channel cell base station, then what is thesignal to interference ratio for a mobile re-ceiver in the functioning cell?

(a) pPi =1

SI (b) p

Pi = 1

2 SI

(c)p

Pi = 1 IS

(d)

p

SI

Ans. (a)

Sol.

66. Which one of the following provides a reliableconnection for the transfer of data betweenapplications?

(a) TCP (b) UDP

(c) FTP (d) SMTP

Ans. (a)

Sol.

67. For a GEO satellite, what is the free spaceloss (Ldb) at the equator in terms of carrierwavelength ( )?

(a) 20 log ( ) + 21.98

(b) –20 log ( ) +173.07

(c) 20 log ( ) – 173.07

(d) –20 log ( ) + 21.98

Ans. (b)

Sol. L = 24 d

173.07 – 20log( )

68. If R = Earth’s radius, h = orbit height, = coverage angle, and = minimum el-evation angle, then which one of the follow-ing relations is correct?

(a)R cos ( + )=

R + h cos( )

(b)R cos ( )=h cos ( )





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(c)R cos ( + )=h cos ( )

(d)

R +h = cos ( + ) – cos ( )h

Ans. (a)

Sol.

69. Consider the following statements for publiccircuit-switching network:

1. Private branch exchange (PBX) is an appli-cation of circuit switching.

2. A switching centre that directly supports sub-scribers is known as digital PBX.

3. The link between the subscriber and the net-work, is also referred to as the local loop.



(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (b)

Sol. (i) Private branch exchange (PBX) is an appli-cation of circuit switching.

(ii) A switching centre that directly supports sub-scribers is known as end-office.

70. Consider the following statements regardingthe cellular system/network:

1. Cellular system use open-loop power controland closed-loop power control.

2. For FDMA system, the capacity of a cell ismore as compared to the number of frequencychannels allocated to it.

3. A cell has L potential subscribers and is ableto handle N simultaneous user. If L > N, thenthe system is referred to as nonblocking.



(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (b)

Sol.

71. The fundamental parameter of a single-modefiber is

(a) The core diameter and cladding diameter.

(b) The mode-field diameter.

(c) the cladding diameter.

(d) the buffer coating diameter.

Ans. (a)

Sol. Fundamental parameters of an single-mode fi-bre is core and cladd diameter.

72. Consider the following statements regardingthe advantages of optical fiber communica-tion:

1. Enormous potential bandwidth

2. Electrical isolation.

3. Immunity to interference and cross talk.

4. System reliability and ease of maintenance.



(c) 1, 2 and 3 only (d) 1, 2, 3 and 4

Ans. (d)

Sol.

73. Express the Boolean function F = A + BC asa sum of minterms?

(a) ABC + ABC

(b) ABC + ABC + ABC

(c) ABC + ABC + ABC + ABC + ABC

(d) ABC + ABC + ABC

Ans. (c)

Sol.

1

11 1 1

BC00 01 11 10

0

1

A

F = ABC + ABC + ABC + ABC + ABC

74. Consider the following statements regardingn-channel JFET:

1. The maximum drain current IDSS occurs whengate-to-source voltage VGS = 0V and drain-

https://iesmaster.org/testseries/gate-2022





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to-source voltage DS PV | V | . (VP is pinch-offvoltage)

2. For gate-to-source voltage VGS less than thepinch-off level, the drain current is 0A.

3. For all levels of VGS between 0 V and thepinch-off level, the current ID will range be-tween IDSS and 0A, respectively.



(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (b)

Sol. For VGS < VP

DI 0

75. The circuit given below is a half wave recti-fier. The internal resistance of a diode Rf is

20 and load resistance RL is 1k . The in-put AC source with rms voltage is 110 V. Whatis the DC voltage across the diode?

ACInput Vi

+

–

V+ –

RLi

(a) –28.54 V (b) –38.54 V

(c) –48.54 V (d) –58.54 V

Ans. (c)

Sol. Vdiode, DC = m LI R–

= –3 3–152.5 ×10 ×10

= –48.5 V

76. The circuit given below is the fixed biasing ofthe n-channel JFET. The pinch-off voltage andthe maximum drain to source current is -8Vand 10 mA respectively. What are the valuesof VGSQ and IDQ, respectively?

+–

2 MQ

4 V

D

S

1 k

12 V

VGS+G

–

(a) +4V and 25 mA (b) +4V and 2.5 mA

(c) –4V and 25 mA (d) –4V and 2.5 mA

Ans. (d)

Sol. VGS = –4

ID = 2

–3 410 ×10 1–8

= 2.5 mA

77. Consider the following statements regardingJFET:

1. The relationship between the drain current andgate-to-source voltage of a JFET is a nonlin-ear.

2. The minimum current for JFET occurs atpinch-off voltage defined by VGS = VP.

3. A current controlled device is one in which acurrent defines the operating conditions of thedevice.



(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (a)

Sol. Statement-I and II are true and related to JFET.

78. What is the maximum closed-loop voltage gainthat can be used when the input signal variesby 0.2 V in 10 s with slew rate of op-ampSR = 2V/ s?

(a) 40 (b) 50

(c) 80 (d) 100

Ans. (d)





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Sol. odVS.R

dt

CL –60.2A × 2

10×10

AACL = 100

79. Consider the following statements regarding555 timer:

1. It operates on –5 V to + 18 V supply voltagein both free running and one-shot modes.

2. It has a high current output and it can sourceor sink 500 mA.

3. The output can drive TTL and has a tempera-ture stability of 80 parts per million (ppm) perdegree Celsius change in temperature orequivalently 0.008%/°C.

Which of the above statements are not cor-rect?


(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (c)

Sol. For IC 555 :VCC : 5 to 18VTemperature stability : 0.005% per °CMaximum output current : 200 mA

80. Consider the following statements for nega-tive feedback:

1. It has more linear operation

2. It has improved frequency response

3. It has better stabilized voltage gain

4. It has higher output impedance




Ans. (c)

Sol. Output impedances decreases.

81. The simplified form of the function

F(A, B, C, D) = m(1,5,6,7,11,12,13,15) is

(a) A C D + A BC + ABC + ACD +BD

(b) A CD + A BC + ABC + ACD +BD

(c) A CD + A BC + AB C + ACD

(d) A CD + A BC + ABC + ACD

Ans. (b)

Sol.

1

10 1 1

CD00 01 11 10

00

AB

1 11

1

01

11

10

F = ACD + ABC + ABC + ACD + BD

82. Consider the following statements regardingthe Moore and Mealy models

1. In the Mealy circuit, the final output dependsonly on the present state of memory elements.

2. In the Moore circuit, output can change inbetween the clock edges if the external in-puts change.

3. The implementation of a logic function inMealy circuit needs more number of statesthan Moore circuit.

Which of the above statements are not cor-rect?


(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (c)

Sol. In Moore circuit, output circuit does depend uponpresent state.

83. In a Johnson’s counter, all the negative trig-gered J-K flip-flops are used. Initially all theflip-flops are in reset condition and the out-puts are Q3Q2Q1Q0 = 0000. What are theoutputs of the flip-flops after the fifth nega-tive going pulse?

(a) Q3Q2Q1Q0 = 0101

(b) Q3Q2Q1Q0 = 1000

(c) Q3Q2Q1Q0 = 0010

(d) Q3Q2Q1Q0 = 1110





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Ans. (d)

Sol.

00 0 0

Q3 Q2 Q1 Q0

1st CLK : 1 0 0 02nd CLK : 1 1 0 03rd CLK : 1 1 1 04th CLK : 1 1 1 15th CLK : 0 1 1 1Therefore, Q0Q1Q2Q3 = 1110

84. Consider the following statements regardingPROM/EPROM

1. The erasable programmable ROM using ul-traviolet erasing is known as EPROM.

2. The ROM that makes use of the electricalvoltage for erasing is known as electricallyalterable ROM.

3. A PROM can be programmed many timesafter fabrication.



(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (a)

Sol. A PROM can be programmed only one timeafter fabrication by fusible link

85. What are the values of Ra, Rb and Rc respec-tively, after transforming the Wye networkshown in the figure to a delta network?

R1 R2

R3

a b

c

10 20

40

(a) 140 , 70 and 45

(b) 70 , 140 and 35

(c) 140 , 70 and 35

(d) 40 , 70 and 25

Ans. (c)

Sol.Rc

Rb Ra

a b

c

10 20

40

Ra = 80040 + 20 + = 14010

Rb = 40010 + 40 + = 7020

Rc = 20×1010 + 20 + = 35

40

86. The number of links in the graph shown in thefigure is

f

a b21 3

c d e

4

(a) 3 (b) 4

(c) 2 (d) 5

Ans. (a)

Sol. l = b – (n – 1)

l = 6 – (4 – 1) = 3

87. Which one of the following contains lessernumber of nodes than the original graph?

(a) Proper subgraph

(b) Improper subgraph

(c) Planar graph

(d) Non-planar graph





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Ans. (a)

Sol.

88. Consider the following statements regardingduality:

1. The dual networks are obtained for both ACand DC circuits and they are based onKirchhoff’s laws.

2. Dual circuits are not obtained in planar net-works.

3. Two networks are said to be dual networks ifmesh equations of one network have thesame form as the nodal equations of the other.



(c) 2 and 3 only (d) 1, 2 and 3

Ans. (b)

Sol. Dual circuits are obtained in planner networks.

89. The current gain

o

i

II

for the given circuit is

4

2H

i (t)o

i (t)i 0.5F

(a)

2s s + 2 , where s = j

s + 2s +1

(b)

2s s +1 , where s = j

s + s +1

(c)


s + 2s +1

(d)


s + s + 2

Ans. (a)

Sol.

o

1

I sI s =

2

4 + 2s s s + 2=2 s + 2s +14 + 2s +s

90. The poles and zeros of the given circuit are

6

2H

+–v (t)o

i (t)1

10

0.1F

(a) poles : –0.683 and –7.317

zeros : –1 and – 3

(b) poles : –0.483 and –5.317


(c) poles : –0.383 and –4.317


(d) poles : –0.583 and –6.317


Ans. (a)

Sol. Y = 1 1 0.1s 1/ 2+ = +

1 6 + 2s s +1 s + 310 +0.1s

Z =

2s +1 s + 3

0.1s + 0.8s + 0.5

Zeros : –1, –3Poles : –0.683, –7.317

91. Which one of the following has all the poles

of the function lie on the j -axis?

(a) L-C function (b) R-L function

(c) R-C function (d) Y function

Ans. (a)

Sol. L-C function

92. Which one of the following is an LC immit-tance function?

(a)

2

2 2Ks s + 4Z s =

s +1 s + 3

(b) 5 3

4 2s + 4s + 5sZ s =

3s + 6s

(c)

2 2

2 2K s +1 s + 9Z s =s + 2 s +10





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(d)

2 2

22 s +1 s + 9Z s =

s s + 4

Ans. (d)

Sol. Z(s) =

2 2

22 s +1 s + 9

s s + 4

Pole : s = 0, ±j2Zero : s = ±j, ± j3

93. Which one of the following not the property ofpositive real function?

(a) If F(s) is positive real, then 1/F(s) is not a posi-tive real,

(b) The sum of positive real functions is positivereal.

(c) The poles and zeros of a positive real func-tion cannot be in the right half of the s-plane.

(d) Only simple poles with real positive residuescan exist on the j-axis

Ans. (a)

Sol.

94. Which one of the following is the transmis-sion matrix equation for network Na if twonetworks Na and Nb are cascaded as shownin the figure?

V1

+

–

I1

V2

+

–Na Nb

I2a

V2a

+

–

I1b

V1b

+

–

I2

(a)a a 2a1

a a 2a1

A B –VV=

C D II

(b)a a 2a1

a a 2a1

A B VV=

C D –II

(c)a a 2a1

a a 2a1

A B –VV=

C –D II

(d)a a 2a1

a a 2a1

A B VV=

–C D –II

Ans. (b)

Sol.a a1 2

1 2a a

A BV V=I –IC D

95. Which one of the following theorems becomesimportant if the circuit has sources operatingat different frequencies?

(a) Norton theorem

(b) Thevenin theorem

(c) Superposition theorem

(d) Maximum power transfer theorem

Ans. (c)

Sol. Superposition theorem

96. What is the value of Zth at terminal a – b ofthe given Thevenin circuit?

+– –j4

a bj26

1075 20° V

(a) Zth = (8.4 – j1.2)

(b) Zth = (10.3 – j2.3)

(c) Zth = (11.3 – j2.9)

(d) Zth = (12.4 – j3.2)

Ans. (d)

Sol. 10 + [–j4 || (6 + j2)]

= (12.4 – j3.2)

97. Consider the following statements for accu-racy of the instrument:

1. The accuracy of the instrument may be speci-fied in terms of limits of errors.

2. The specification of a point accuracy givesany information about the general accuracyof the instrument.

3. The best way to conceive the idea of accu-racy is to specify it in terms of the true valueof the quantity being measured.



(c) 1, 2 and 3 (d) 2 and 3 only





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Ans. (b)

Sol. Point accuracy does not give any informationabout general accuray of the instrument.

98. Consider the following statements for deflec-tion and null type instruments:

1. Deflection type of instruments are more ac-curate than null type of instruments.

2. Deflection type of instruments can be highlysensitive as compared with the null type ofinstruments.

3. Null type of instruments are more suitable formeasurements under dynamic conditions thandeflection type of instruments.



(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (c)

Sol.

99. A digital timer with eight readout is stated tohave accuracy of 0.005 percent of reading,±1 in the final digit. Readout is in s, ms and

s. Assuming that the instrument meets itssspecifications, the maximum likely errors whenthe reading is 05000000 s is

(a) 251 s (b) 260 s

(c) 261 s (d) 250 s

Ans. (d)

Sol. E1 = 0.005% of reading

= 0.005 ×100 5000000 µsec = 250 msec

E2 = ± 1 final digit = –8

81 = 10

10

Total error, ET = E1 + E2

= 250 × 10–6 + 10–8 250 µsec

100. Which one of the following is essentially apermanent magnet moving coil instrumentdesigned to be sensitive to extremely lowcurrent levels?

(a) Multimeter

(b) Galvanometer

(c) Electrodynamic Wattmeter

(d) Electrodynamic Voltmeter

Ans. (b)

Sol.

101. A strain gauge is bonded to a beam 0.1 mlong and has a cross-sectional area 4 cm2.Young’s modulus for steel is 207 GN/m2. Thestrain gauge has an unstrained resistance of240 and a gauge factor of 2.2. When aload is applied, the resistance of gaugechanges by 0.013 . . The change in lengthof the steel beam is

(a) 1.23 × 10-6 m (b) 2.46 × 10-6 m

(c) 4.92 × 10-6 m (d) 9.84 × 10-6 m

Ans. (b)

Sol.R

R

= GF × L

L

LL

= –50.013 = 2.46 ×10240 × 2.2

L = 2.46 × 10–5 × 0.1 = 2.46 µm

L = 2.46 × 10–6 m

102. A digital frequency meter has a time basederived from a 1 MHz clock generator fre-quency-divided by decade counters. What isthe measured frequency when a 1.512 kHzsine wave is applied and the time base usessix decade counters?

(a) 1.512 kHz (b) 15.12 kHz

(c) 1.412 kHz (d) 14.12 kHz

Ans. (a)

Sol. Fmeasured = 1.512 kHz

103. Which of the following instruments have largescales for easy reading?

(a) Vacuum-tube voltmeter (VTVM) and a FET-input multimeter

(b) Vacuum-tube voltmeter (VTVM) and an ana-log electronic ammeter





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(c) FET-input multimeter and an analog electronicammeter

(d) FET-input multimeter and an analog electronicvoltmeter

Ans. (a)

Sol.

104. If a resistor is known to have a resistance of500 with a possible error of 50 , the

50 is

(a) relative error (b) absolute error

(c) gross error (d) systematic error

Ans. (b)

Sol.

105. Consider the following statements for dynamiccharacteristics of a measurement system:

1. Fidelity is defined as the degree to which ameasurement system indicates changes in themeasured quantity without any dynamic er-ror.

2. Dynamic error is the difference between thetrue value of the quantity changing with timeand the value indicated by the measurementsystem if no static error is assumed.

3. Measuring lag is the retardation in the re-sponse of a measurement system to changesin the measured quantity.



(c) 1, 2 and 3 (d) 2 and 3 only

Ans. (c)

Sol.

106. Current was measured during a test as of 30.4A, flowing in a resistor of 0.105 . It wasdiscovered later that the ammeter reading waslow by 1.2 percent and the marked resistancewas high by 0.3 percent. What is the truepower as a percentage of the power that wasoriginally calculated?

(a) 118.4% (b) 109.7%

(c) 102.1% (d) 104.8%

Ans. (c)

Sol. Itrue = 1.230.4 + × 30.4100 = 30.765 Amp.

Rtrue = 0.30.105 – ×0.105 = 0.1047100

(Power)true = (30.765)2 × 0.1047 = 99.082 watt(power)measured = (30.4)2 × 1.05 = 97.037 wattTherefore, % true power of measured power

= 99.082 ×10099.037 = 102.1%

107. The LVDT is used in an accelerometer tomeasure seismic mass displacements. TheLVDT and signal conditioning outputs are 0.31mV/mm with a 20 mm core displacement.The spring constant is 240 N/m and the coremass is 0.05 kg. The natural frequency andmaximum measurable acceleration are respec-tively,

(a) 69.3 rad/s and 69.3 m/s2

(b) 69.3 rad/s and 96 m/s2

(c) 15.59 rad/s and 96 m/s2

(d) 15.59 rad/s and 31.18 m/s2

Ans. (b)

Sol. n = k 240= = 69.28 rad / secm 0.05

qmax = 2 A = (69.28)2 × 28 × 10–3

= 96 m/sec2

108. A quartz piezoelectric crystal having a thick-ness of 1.5 mm and voltage sensitivity of 0.05V-m/N is subjected to a pressure of2 MN/m2. The permittivity of the quartz is40.6 × 10-12 F/m. The output voltage is

(a) 150 V (b) 155 V

(c) 165 V (d) 300 V

Ans. (a)

Sol. Vo = P.g.t = 0.05 × 2 × 106 × 1.5 × 10–3

= 150 volt





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109. Which one of the following is a metallic crys-tal structure which has a cubic unit cell withatoms located at all eight corners and a singleatom at the cube centre?

(a) Face-centered cubic crystal structure

(b) Body-centred cubic crystal structure

(c) Cubic crystal structure

(d) Metal crystalline structure

Ans. (b)

Sol.

110. What is the atomic packing factor for FCCcrystal structure?

(a) 0.96 (b) 0.48

(c) 0.74 (d) 0.37

Ans. (c)

Sol. APF = 0.74 for FCC

111. Consider the following statements regardingcrystal defects:

1. In metals, a self-interstitial introduces rela-tively large distortions in the surroundinglattice because the atom is substantiallylarger than the interstitial position in whichit is situated.

2. All crystalline solids do not contain vacan-cies and, it is possible to create such amaterial that is free of these defects.

3. Impurity point defects are found in solidsolutions, of which there are two typessubstitutional and interstitial.

Which of the above statements is/are correct?


(c) 3 only (d) 2 only

Ans. (a)

Sol.

112. Which one of the following represents the up-per and lower upper bound of the elastic modu-lus respectively? (E and V denote the elasticmodulus and volume fraction respectively; thesubscripts c, m and p represent composite,matrix and particulate phases respectively)

(a) m mc

p p

E VE (u) = andE V

m pc

m p p m

E EE ( ) =

V E + V El

(b) m pc

m p p m

E EE (u) = and

V E + V E

cE ( )l = EmVm + EpVp

(c) Ec(u) = EmVm + EpVp and

m pc

m p p m

E EE ( ) =

V E + V El

(d) Ec(u) = EmVm + EpVp and

m p p mc

m p

V E + V EE ( ) =

E El

Ans. (c)

Sol.

113. Which one of the following does not comeunder the category of ceramic material?

(a) Al2O3 (b) SiO2

(c) Si2N4 (d) SiC

Ans. (c)

Sol. Si2N4

114. Consider the following statements regardingcorrosion of ceramic material:

1. Ceramic materials are much better suited towithstand most of these environments for rea-sonable time periods than are metals.

2. Corrosion of ceramic materials generally in-volves simple chemical dissolution, in con-trast to the electrochemical processes foundin metals.

3. Ceramic materials are not frequently used be-cause of their non-resistance to corrosion.



(c) 3 only (d) 1 and 2 only

Ans. (d)

Sol. Ceramic materials have resistance to corrosion.





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115. For a ferromagnetic material, which one ofthe following relationships is correct betweenmagnetic flux density and magnetization?

(a) 0B 2 M (b) 0B M

(c) 0MB

2

(d) 0BM

Ans. (b)

Sol. B = µo(H + m) ( H = 0)

oB m

116. Which of the following statements is not cor-rect regarding ferrites?

(a) Ferrites, with large magnetostrictive effects,are used in electromechanical transducers.

(b) Ferrites have very high resistivity.

(c) Hard magnetic ferrites are used for the manu-facture of light weight permanent magnets.

(d) Soft magnetic materials can be used for mak-ing permanent magnets.

Ans. (d)

Sol. Hard materials are used to make permanentmagnets.

117. Which one of the following materials displaysthe behavior of antiferromagnetism?

(a) Manganese oxide (b) Iron

(c) Nickel (d) Cobalt

Ans. (a)

Sol. Iron, nickel, cobalt are the examples of ferro-magnetic materials.

118. Consider the following statements for super-conductivity:

1. Superconducting magnets capable of gener-ating high fields with low power consumptionare currently being employed in scientific testand research equipment.

2. One of the potential applications of supercon-ducting materials is electrical power transmis-sion through superconducting materials —power losses would be extremely low, and theequipment would operate at low voltage lev-els.

3. Type II superconductors are preferred overtype I for most practical applications by vir-tue of their higher critical temperatures andcritical magnetic fields.


(a) 1 only (b) 2 and 3 only

(c) 3 only (d) 1, 2 and 3

Ans. (d)

Sol.

119. Which one of the following statements is notcorrect regarding the features of ceramics?

(a) Ceramics are hard, strong and dense.

(b) Ceramics are stronger in compression thanin tension.

(c) Ceramics have very poor dielectric proper-ties.

(d) Ceramics are weak in impact strength.

Ans. (c)

Sol. Ceramics have good dielectric properties.

120. What is the packing efficiency of diamond?

(a) 0.17 (b) 0.34

(c) 0.24 (d) 0.48

Ans. (b)

Sol. For diamond : APF = 0.34

121. A current of 5A in primary coil of a circuit isreduced to zero at a uniform rate in 10–3

seconds. If coefficient of mutual inductanceis 2H, then the induced emf in the secondarycoil is

(a) 10–4 V (b) 104 V

(c) 10–6 V (d) 106 V

Ans. (b)

Sol. e2 =

–32 5 – 0

10 = 10 × 103

e2 = 104

122. A wire of resistor 10 is drawn out so thatits length is increased to twice its originallength. Then, the new resistance is





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(a) 20 (b) 5

(c) 30 (d) 40

Ans. (d)

Sol. R = 1

2 11

, = 2Al l l

Volume = constant

V1 = V2, 1 1 2 2A = Al l

A2 = 1a2

R2 = 1

14

a

l

R2 = 4(R1) = 40

123. What is the magnitude of emf induced in a200 turn coil with cross-sectional area of0.16m2, if the magnetic field through the coilchanges from 0.10 Wb/m2 to 0.50 Wb/m2 ata uniform rate over a period of 0.02 seconds?

(a) –520 V (b) –640 V

(c) –725 V (d) –815 V

Ans. (b)

Sol. e = Nd 10.4× 0.161– = –200dt 0.02

= –640 voltss

124. In an AC circuit, the voltage source V is asfollows: V = 100 sin(100t)volt. The rms valueof voltage is

(a) 35.35 V (b) 40.35 V

(c) 80.7 V (d) 70.7 V

Ans. (d)

Sol. Vrms = 100

2 = 70.7 voltss

125. Which one of the following statements is notcorrect regarding the characteristics of idealtransformer?

(a) There is no leakage flux.

(b) There are no losses in electric circuit or inmagnetic circuit.

(c) The resistance of both the windings is infi-nite.

(d) The permeability of the core is infinite andzero reluctance.

Ans. (c)

Sol.

126. Which one of the following is not the indica-tion of a fully-charged cell?

(a) Intensity

(b) Gassing

(c) Voltage

(d) Specific gravity of the electrolyte

Ans. (b)

Sol.

127. For the given circuit, the currents i1 and i3 are

+–i4

2

8i3i2

i1

2

4P

i1

i26

Io10V

i2 i3Q

5A3Io

(a) i1 = –2.5A and i3 = 3.93A

(b) i1 = 7.5 A and i3 = –2.5A

(c) i1 = 3.93A and i3 = 2.14A

(d) i1 = –7.5A and i3 = 3.93A

Ans. (d)

Sol. 6i2 + 2i1 + 4i3 + 8(i3 – i4) = 03i2 + i1 + 6i3 – 4i4 = 0 ... (1)–i1 + i2 = 5 ... (2)i2 – i3 = 3io ... (3)8(i4 – i3) + 2i4 + 10 = 0–4i3 + 5i4 = –5 ... (4)10 = –i4 ... (5)i1 = –7.5 Ai3 = 3.93 A

128.. What is the equivalent resistance Rab in thegiven circuit?





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4 5

1

3

6

1

12

10

Rab

a

b b

c d

b

(a) 34.08 (b) 11.20

(c) 42.16 (d) 17.82

Ans. (b)

Sol.10 1 1

3 6 124

1

10 1

2 1

Rab = 11.2

129. Consider the following statements for induc-tors:

(1) An inductor acts like a short circuit to DC.

(2) The current through an inductor cannotchange instantaneously.

(3) The current through an inductor can changeinstantaneously.

(4) An inductor acts like an open circuit to DC.



(c) 2 only (d) 3 and 4 only

Ans. (b)

Sol. (i) An inductor acts like a short circuit to DC.(ii) The current through inductor cannot change

instantaneously.

130. What is the phase angle between

i1 = –4sin(377t + 25°) and i2 = 5cos(377t – 40°)?

(a) 155°, (i1 leads i2)

(b) 145°, (i2 leads i1)

(c) 135°, (i1 leads i2)

(d) 125°, (i2 leads i1)

Ans. (a)

Sol. I1 = 4cos(377t + 25° + 90°)= 4cos(377t + 115°)I2 = 5cos(3775 – 40°)155°, I1 leads I2.

131. Which one of the following laws states thatthe line integral of the tangential componentof H around a closed path is the same as thenet current Ienc. enclosed by the path?

(a) Biot-Savart’s law

(b) Lenz’s law

(c) Gauss’s law

(d) Ampere’s circuit law

Ans. (d)

Sol. H d

l = Ienc.

132. Consider the following statements regardingan ideal transformer

(1) Coils have very large reactances.

(2) Coupling coefficient is equal to unity

(3) Primary and secondary coils are not lossless.



(c) 2 and 3 only (d) 1 only

Ans. (b)Sol.

133. The total efficiency of an injection laser witha GaAs active region is 18%. The voltageapplied to the device is 2.5 V and the bandgapenergy for GaAs is 1.43 eV. The externalpower efficiency of the device is

(a) 5% (b) 10%

(c) 15% (d) 20%

Ans. (b)

Sol. ex1.43= 0.18× ×100% 10%2.5





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134. The slope of the output characteristics of atransistor in CE configuration is higher thanthat in CB configuration due to which one ofthe following effects?

(a) Zener effect

(b) Early effect

(c) Avalanche effect

(d) Transistor effect

Ans. (b)

Sol. The output current (IC) increases with increasein collector to emitter voltage (VCE). This isdue to base width modulation is called earlyeffect.

135. Which one of the following statements is cor-rect regarding the comparison between Ava-lanche and Zener effect?

(a) Zener effect is caused by impact ionization.

(b) Zener diodes have higher resistance.

(c) Avalanche effect occurs at voltages usuallyabove 7V.

(d) Avalanche diodes have lower resistance.

Ans. (c)

Sol. Avalanche effect occurs at voltage usually above7V.

136. A sinusoidal input is given to the networkshown below. The output waveform is

–7V

t

7Vvi

o R+

–

– +C

vi

+

– +

–5V

– vo

(a) t

vo(V)

o–2V

+12

(b) to–2

+5

vo(V)

(c) to

–7

2

vo(V)

(d) to

–12

2

vo(V)

Ans. (*)

Sol.

137. For enhancement-type n-channel MOSFETwith drain current ID = 10 mA, VGS = 8V andVT = 2V, the device constant k is

(a) 0.139 mA/V2 (b) 0.278 mA/V2

(c) 0.387 mA/V2 (d) 0.556 mA/V2

Ans. (b)

Sol. ID = K(VGS – VTN)2

10 × 10–3 = K(8 – 2)2

K = 0.278 mA/V2

138. Which one of the following statements is cor-rect regarding shunt-series feedback ampli-fier topology?

(a) The currents are compared and the outputvoltages are sampled.

(b) The currents are compared and the outputcurrents are sampled.

(c) The voltages are compared and the outputcurrents are sampled.

(d) The voltages are compared and the outputvoltages are sampled.

Ans. (b)

Sol. At input : current mixingAt output : current sampled

139. A Hartley oscillator uses L1 = 2 mH and L2 =1.5 mH. The range of capacitance so that thefrequency of oscillation can be varied between1000 kHz to 2000 kHz are

(a) Cmax = 7.2 pF and Cmin = 1.8 pF





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(b) Cmax = 9.2 pF and Cmin = 0.8 pF

(c) Cmax = 7.2 pF and Cmin = 0.8 pF

(d) Cmax = 9.2 pF and Cmin = 1.8 pF

Ans. (a)

Sol. f = 1 2

12 L +L C

For Cmax = 23 –3

1

2 ×1000×10 3.5×10Cmax = 7.2 pF

Cmin = 23 –3

1

2 × 2000 ×10 3.5 ×10 = 1.8 pF

140. Which one of the following statements is cor-rect regarding integrated circuit fabrication?

(a) IC offers increased reliability, improved per-formance, high speed and lower power con-sumption.

(b) IC is a miniature, low cost electronic circuitfabricated on a multi crystal chip of silicon.

(c) IC is a miniature, high cost electronic circuitfabricated on a multi crystal chip of silicon.

(d) IC offers decreased reliability, improved per-formance, low speed and higher power con-sumption.

Ans. (a)

Sol.

141. What is the value of capacitor of the Wienbridge oscillator operating at resonant fre-quency of 10 kHz with resistance of 100 k ?

(a) 149 pF (b) 159 pF

(c) 169 pF (d) 189 pF

Ans. (b)

Sol. f = 1

2 RC

C = 4 51

2 ×10 ×10 = 159 pF

142. A monolithic metal oxide semiconductor(MOS) non-polarized capacitor which is aparallel plate capacitor with SiO2 as dielec-tric. A surface thin film of metal (aluminium)is the top plate. The bottom plate consists of

the heavily doped n+ region that is formedduring emitter diffusion. What is the typicalvalue of capacitance for an oxide thicknesso f500 Å of this MOS capacitor?

(a) 0.1 pF/mil2 (b) 0.2 pF/mil2

(c) 0.3 pF/mil2 (d) 0.4 pF/mil2

Ans. (d)Sol.

143. For the given figure, the output voltage is

R

R1

V2

V1

Rf

R2

–+ Vo

(a) f f0 2 1

1 2

R R +RV = V + V

R R +R

(b) f f0 2 1

f f 1 2

R +R R +RRV = V + VR R R +R

(c) f f 1 20 2 1

f

R R +R R +RV = V + V

R R R +R

(d) f f 20 2 1

1 2

R R +R RV = V + V

R R R +R

Ans. (d)

Sol. Vo = E F 22 1

1 2

–R R +R RV + V

R R R +R

144. In a BJT switching circuit, supply voltage isVCC = 9V, biasing resistors are RB = 15 k ,RC = 6.8 k and the transistor has an hFEvalue of 25. What is the minimum input volt-age required to switch the transistor into satu-ration when VCE = 0.2V?

(a) 1.48 V (b) 0.78 V

(c) 5 V (d) 2.5 V

Ans. (a)

Sol. Vin = IB(15K) + 0.7

= 10 4 – 0.2 15K15K + 0.7 = + 0.725 68K 25

= 1.476





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Directions: Each of the next six (06) items con-sists of two statements, one labelled as the ‘State-ment (I)’ and the other labelled as ‘Statement (II)’.You are to examine these two statements carefullyand select the answers to these items using thecodes given below:

Codes:

(a) Both statement (I) and statement (II) are indi-vidually true and Statement (II) is the correctexplanation of Statement (I).

(b) Both Statement (I) and Statement (II) are in-dividually true, but Statement (II) is not thecorrect explanation of Statement (I).

(c) Statement (I) is true, but Statement (II) is false.

(d) Statement (I) is false, but Statement (II) istrue.

145. Statement (I): Ge and Si are said to havenegative temperature coefficient of resistivity.

Statement (II): Ge and Si show a reduction inresistance with increase in temperature.

Ans. (a)

Sol. As temperature increases, resistance decreases,therefore, conductivity increases.

146. Statement (I): A linear network which con-tains two or more independent sources canbe analyzed to obtain the various voltagesand branch currents by allowing the sourcesto act one at a time, then superposing theresults.

Statement (II): Superposition cannot be di-rectly applied to the computation of the power.

Ans. (b)

Sol.

147. Statement (I): Metals are extremely goodconductors of electricity and heat, and arenot transparent to visible light.

Statement (II): Ceramics are compoundsbetween metallic and non-metallic elements.

Ans. (b)

Sol.

148. Statement (I): M-ary PSK can be used totransmi t digi tal data ov er a non-l inearbandpass channel, whereas M-ary QAM re-quires the use of a linear channel.

Statement (II): M-ary PSK and M-ary QAMare examples of non-linear modulation.

Ans. (c)

Sol.

149. Statement (I): Linear system may have mul-tiple equilibrium states.

Statement (II): If a system is BIBO stable,must also be zero-input or asymptoticallystable.

Ans. (d)

Sol.

150. Statement (I): The total flux out of a closedsurface is equal to the net charge enclosedwithin the surface.

Statement (II): An electric field is completelyspecified by its intensity vector.

Ans. (b)

Sol.

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