DUET Question Paper 2019 for M.Tech Microwave Electronics

DU MTech Microwave Electronics

Topic:- DU_J19_MTECH_ME

1) If the capacitance of an abrupt p-n junction varactor diode is 1 nF at zero bias then capacitance at
reverse bias potential voltage of 99 V is ________ nF (The built-in potential is 1 V) [Question ID =
24292]

1. 0.01 [Option ID = 37167]
2. 1.1 [Option ID = 37169]
3. 1 [Option ID = 37166]
4. 0.1 [Option ID = 37168]

1 [Option ID = 37166]

2) The amplitude of a random signal is uniformly distributed between -5 V and 5 V. If the signal to
quantization noise ratio required in uniformly quantizing the signal is 43.5 dB, the step of the
quantization is approximately [Question ID = 24302]

1. 0.578 V [Option ID = 37208]
2. 1.1 V [Option ID = 37207]
3. 2.2 V [Option ID = 37209]
4. 0.078 V [Option ID = 37206]

0.078 V [Option ID = 37206]

3) If an air filled rectangular waveguide has width 20 mm and height 10 mm, the bandwidth for single
mode operation is [Question ID = 24319]

1. 7.5 GHz [Option ID = 37274]
2. 5.0 GHz [Option ID = 37277]
3. 6 GHz [Option ID = 37281]
4. 15 GHz [Option ID = 37279]

7.5 GHz [Option ID = 37274]

4) Area bounded by the curve y=x2 and the lines x=4 and y=0 is [Question ID = 24243]

1. ∞ [Option ID = 36970]
2. 21.33 [Option ID = 36971]
3. 42.66 [Option ID = 36972]
4. 10.66 [Option ID = 36973]

∞ [Option ID = 36970]

5) In a monolithic IC, resistors are formed from [Question ID = 24280]

1. p-type semiconductors [Option ID = 37120]
2. aluminum ribbons [Option ID = 37118]
3. meta materials [Option ID = 37121]
4. ceramic materials [Option ID = 37119]

aluminum ribbons [Option ID = 37118]

6) Velocity of light in a medium with relative permittivity of 3 and relative permeability of 2 respectively
is [Question ID = 24315]

1. [Option ID = 37258]

2. [Option ID = 37264]

3. [Option ID = 37262]

4. [Option ID = 37260]

[Option ID = 37258]

7) Two infinite parallel plates 10mm apart have maintained a potential difference of 100 V between
them. The acceleration of an electron placed between them is

[Question ID = 24330]

1. 0.9x1012 m/s2 [Option ID = 37319]
2. 0.56x1010 m/s2 [Option ID = 37320]
3. 1.76x1015 m/s2 [Option ID = 37318]
4. 1.76x1018 m/s2 [Option ID = 37321]

1.76x1015 m/s2 [Option ID = 37318]

8) The source in a microwave oven mostly generates power within the range of [Question ID = 24340]

1. 1.5 kW – 15 kW [Option ID = 37360]
2. 1W – 150 W [Option ID = 37361]
3. 15 kW-1 MW [Option ID = 37358]
4. 150W – 1.5 kW [Option ID = 37359]

15 kW-1 MW [Option ID = 37358]

9) The Nyquist sampling interval, for the signal sinc(700t) +sinc(500t) is [Question ID = 24311]

1. [Option ID = 37243]

2. [Option ID = 37245]

3. [Option ID = 37242]

4. [Option ID = 37244]

[Option ID = 37242]

10) The peak-to-peak input to an 8-bit PCM coder is 2 volts. The signal power-to quantization noise
power ratio (in dB) for an input of 0.5cos(ωm t) is [Question ID = 24306]

1. 49.8 [Option ID = 37224]
2. 18 [Option ID = 37223]
3. 32 [Option ID = 37225]
4. 48 [Option ID = 37222]

48 [Option ID = 37222]

11) In a FM system, a carrier of 100 MHz is modulated by a sinusoidal signal of 5 KHz . The bandwidth by
Carson’s approximation is 1 MHz. If y(t)=(modulated waveform)3 , then by using Carson’s
approximation, the bandwidth of y(t) and the spacing of spectral components are respectively.

[Question ID = 24309]

1. 1 MHz, 5 KHz [Option ID = 37234]
2. 1 MHz, 15 KHZ [Option ID = 37236]
3. 3 MHz, 15 KHz [Option ID = 37237]
4. 3 MHz, 5 KHz [Option ID = 37235]

1 MHz, 5 KHz [Option ID = 37234]

12) Hexa-decimal equivalent to decimal number 894 is [Question ID = 24277]

1. 37E [Option ID = 37108]
2. 6AD [Option ID = 37109]
3. 35A [Option ID = 37106]
4. 1DF [Option ID = 37107]

35A [Option ID = 37106]

13) A JFET amplifier has gm= 2 mA/V and rd= 500 kΩ. If the load resistance is 10 kΩ then the voltage
gain is _____ [Question ID = 24294]

1. -4.9 [Option ID = 37175]
2. -19.6 [Option ID = 37176]
3. -39.2 [Option ID = 37174]
4. -1.00 [Option ID = 37177]

-39.2 [Option ID = 37174]

14) The characteristic impedance of a lossless transmission line is 750 Ω and it is terminated by a
resistance of 450 Ω. The reflection coefficient is [Question ID = 24329]

1. 1/4 [Option ID = 37316]
2. 1/3 [Option ID = 37315]
3. 1/2 [Option ID = 37314]
4. 1 [Option ID = 37317]

1/2 [Option ID = 37314]

15) In a GSM system, 8 channels can co-exist in 200 kHz bandwidth using TDMA. A GSM based cellular
operator is allocated 5 MHz bandwidth. Assuming a frequency reuse factor of 1/5 , i.e. a five-cell repeat
pattern, the maximum number of simultaneous channels that can exist in one cell is [Question ID =
24303]

1. 5 [Option ID = 37213]
2. 25 [Option ID = 37210]
3. 40 [Option ID = 37212]
4. 200 [Option ID = 37211]

25 [Option ID = 37210]

16) A 3 Ω resistance coil has a time constant of 1.8 sec. The current flowing in it one second after 10 V is
applied. [Question ID = 24269]

1. 0.5 A [Option ID = 37074]
2. 0.8 A [Option ID = 37075]
3. 1.42 A [Option ID = 37077]
4. 2A [Option ID = 37076]

0.5 A [Option ID = 37074]

17)
A signal x(t)=2cos(π104 t) volts is applied to an FM modulator with the sensitivity constant of 10
kHz/volt. The modulation index of the FM wave is

[Question ID = 24297]

1. 4 [Option ID = 37189]
2. 2 [Option ID = 37187]
3. 4⁄π [Option ID = 37188]
4. 2⁄π [Option ID = 37186]

2⁄π [Option ID = 37186]

18) If a DC current gain (β) of BJT is 45 then base transport factor is _______ (Hint:- emitter injection
efficiency is 0.995) [Question ID = 24293]

1. 0.786 [Option ID = 37172]
2. 0.983 [Option ID = 37170]
3. 0.491 [Option ID = 37171]
4. ∞ [Option ID = 37173]

0.983 [Option ID = 37170]

19) The area bounded by the curves y2=4x and x2=4y is [Question ID = 24240]

1. 8 [Option ID = 36958]
2. 32/3 [Option ID = 36959]
3. 16/3 [Option ID = 36961]
4. 16 [Option ID = 36960]

8 [Option ID = 36958]

20) Suppose that the eigen values of matrix A are 1,2,4. The determinant of (A-1)T is ______ [Question
ID = 24238]

1. 1.1 [Option ID = 36952]
2. 1 [Option ID = 36950]
3. 0.11 [Option ID = 36951]
4. 0.125 [Option ID = 36953]

1 [Option ID = 36950]

21) The Gunn diode is used in [Question ID = 24334]

1. mixer [Option ID = 37334]
2. oscillator [Option ID = 37337]
3. circulator [Option ID = 37336]
4. coupler [Option ID = 37335]

mixer [Option ID = 37334]

22) A printed circuit board has eight different locations in which a component can be placed. If four
different components are to be placed on the board, how many different designs are possible? [Question
ID = 24248]

1. 1654 [Option ID = 36993]
2. 980 [Option ID = 36990]
3. 1680 [Option ID = 36991]
4. 1780 [Option ID = 36992]

980 [Option ID = 36990]

23) A generator of 50 Ω internal impedance and operating frequency of 3 GHz feeds a 75Ω load via a
coaxial line of characteristic impedance Z and length l. The value of Z and l for the maximum power
transfer is, respectively

[Question ID = 24324]

1. 62.5 Ω, 10 cm [Option ID = 37294]
2. 62.5 Ω, 10 cm [Option ID = 37297]
3. 61.24 Ω, 2.5 cm [Option ID = 37296]
4. 61.24 Ω, 10 cm [Option ID = 37295]

62.5 Ω, 10 cm [Option ID = 37294]

24) The threshold voltage of an n-channel MOSFET can be increased by [Question ID = 24295]

1. reducing the gate-oxide thickness [Option ID = 37179]
2. reducing the channel dopant concentration [Option ID = 37181]
3. reducing the channel length [Option ID = 37180]
4. increasing the channel dopant concentration [Option ID = 37178]

increasing the channel dopant concentration [Option ID = 37178]

25) If the magnetic field of B=3.0 weber/m2 is used to accelerate a proton in cyclotron then the
frequency of the oscillator connected across the dees is____

[Question ID = 24296]

1. 45.76 MHz [Option ID = 37184]
2. 6.76 MHz [Option ID = 37185]
3. 91.52 MHz [Option ID = 37183]
4. 22.88 MHz [Option ID = 37182]

22.88 MHz [Option ID = 37182]

26) If E denotes expectation, the variance of a random variable X is given by [Question ID = 24310]

1. E[X2] –E2[X] [Option ID = 37241]
2. E[X2] + E2[X] [Option ID = 37238]
3. E[X2] [Option ID = 37239]
4. E2[X] [Option ID = 37240]

E[X2] + E2[X] [Option ID = 37238]

27) When the gate-to-source voltage (VGS) of a MOSFET with threshold voltage of 400 mV working in
saturation is 900 mV, the drain current is observed to be 1 mA. Neglecting channel length modulation

effect and assuming that the MOSFET is operating at saturation, the drain current for an applied (VGS) of
1400 mV is [Question ID = 24288]

1. 4.0 mA [Option ID = 37153]
2. 2.0 mA [Option ID = 37151]
3. 3.5 mA [Option ID = 37152]
4. 0.5 mA [Option ID = 37150]

0.5 mA [Option ID = 37150]

28) For an input power of 1 mW, an attenuator gives an output power of 0.1 mW. If an input of 10 mW
power is applied to same attenuator, the output power in mW is [Question ID = 24322]

1. 0 mW [Option ID = 37288]
2. 0.1 mW [Option ID = 37286]
3. 5 mW [Option ID = 37284]
4. 1 mW [Option ID = 37283]

1 mW [Option ID = 37283]

29) The relative power in VSWR meter is displayed as 30 dB at the output of attenuator on applying 10
mW input power. The attenuation of this attenuator is [Question ID = 24335]

1. 20 dB [Option ID = 37338]
2. 40 dB [Option ID = 37341]
3. 0 dB [Option ID = 37340]
4. 30 dB [Option ID = 37339]

20 dB [Option ID = 37338]

30) In a PCM system, if the code word length is increased from 6 to 8 bits, the signal to quantization
noise ratio improves by the factor [Question ID = 24305]

1. 20 [Option ID = 37218]
2. 8 [Option ID = 37219]
3. 16 [Option ID = 37220]
4. 4 [Option ID = 37221]

20 [Option ID = 37218]

31) The VSWR can have any value between [Question ID = 24328]

1. 1 and ∞ [Option ID = 37313]
2. -1 and +1 [Option ID = 37311]
3. 0 and ∞ [Option ID = 37312]
4. 0 and 1 [Option ID = 37310]

0 and 1 [Option ID = 37310]

32) An 3 dB attenuator has a VSWR of 1.02 at the input port, the percentage ratio of power reflected to
power incident at the input of attenuator is

[Question ID = 24323]

1. 0.01% [Option ID = 37291]
2. 0.1% [Option ID = 37290]
3. 1% [Option ID = 37292]
4. 10% [Option ID = 37293]

0.1% [Option ID = 37290]

33) Consider the amplitude modulated signal s(t)=cos(2000πt)+4cos(2400πt)+cos(2800πt) . The ratio
of the power of the message signal to the power of the carrier signal is

[Question ID = 24304]

1. 0.543 [Option ID = 37217]
2. 0.125 [Option ID = 37214]
3. 2 [Option ID = 37215]
4. 0.85 [Option ID = 37216]

0.125 [Option ID = 37214]

34)
The average power delivered to an impedance (4-j3)Ω by a current 5 cos(100πt+100)A is

[Question ID = 24261]

1. 62.5 W [Option ID = 37044]
2. 44.2 W [Option ID = 37043]
3. 125 W [Option ID = 37045]
4. 50 W [Option ID = 37042]

50 W [Option ID = 37042]

35) A communication channel with AWGN operating at a signal to noise ratio SNR >> 1 and bandwidth B
has capacity C1. If the SNR is doubled keeping constant bandwidth, the resulting capacity C2 is given by

[Question ID = 24301]

1. C2 ≈ C1+0.3B [Option ID = 37205]
2. C2 ≈ C1+2B [Option ID = 37202]
3. C2 ≈ C1+B [Option ID = 37204]
4. C2 ≈ 2C [Option ID = 37203]

C2 ≈ C1+2B [Option ID = 37202]

36) The Laplacian operator is actually [Question ID = 24257]

1. [Option ID = 37028]

2. [Option ID = 37029]

3. [Option ID = 37027]

4. [Option ID = 37026]

[Option ID = 37026]

37) The maximum value of the function f(x)=2x2-2x+6 in the interval [0, 2] is [Question ID = 24244]

1. 0 [Option ID = 36974]
2. 1 [Option ID = 36976]
3. ∞ [Option ID = 36977]
4. 10 [Option ID = 36975]

0 [Option ID = 36974]

38)

[Question ID = 24263]

1. -14 V, 24 Ω [Option ID = 37051]
2. 10 V, 24 Ω [Option ID = 37052]
3. -18 V, 24 Ω [Option ID = 37050]
4. 11 V, 18 Ω [Option ID = 37053]

-18 V, 24 Ω [Option ID = 37050]

39)

[Question ID = 24337]

1. 2.88 [Option ID = 37349]
2. 3.26 [Option ID = 37348]
3. 4.25 [Option ID = 37347]
4. 5.76 [Option ID = 37346]

5.76 [Option ID = 37346]

40)

[Question ID = 24331]

1. 4 Ω/m [Option ID = 37323]
2. 2.4 Ω/m [Option ID = 37322]
3. 3.6 Ω [Option ID = 37325]
4. 1.2 Ω/m [Option ID = 37324]

2.4 Ω/m [Option ID = 37322]

41)

[Question ID = 24249]

1. [Option ID = 36994]
2. [Option ID = 36997]

3. [Option ID = 36996]
4. [Option ID = 36995]

[Option ID = 36994]

42)

[Question ID = 24267]

1. 70.34 mA [Option ID = 37068]
2. 94.34 mA [Option ID = 37069]
3. -70.34 mA [Option ID = 37067]
4. -94.34 mA [Option ID = 37066]

-94.34 mA [Option ID = 37066]

43)

[Question ID = 24318]

1. [Option ID = 37267]

2. [Option ID = 37269]

3. [Option ID = 37271]

4. [Option ID = 37273]

[Option ID = 37267]

44)

[Question ID = 24286]

1. [Option ID = 37144]

2. [Option ID = 37142]

3. [Option ID = 37143]

4. [Option ID = 37145]

[Option ID = 37142]

45)

[Question ID = 24333]

1. 200 + j100 Ω [Option ID = 37332]
2. 100 + j50 Ω [Option ID = 37331]
3. 150 + j100 Ω [Option ID = 37333]
4. 2 + j Ω [Option ID = 37330]

2 + j Ω [Option ID = 37330]

46)

[Question ID = 24300]

1. 25% [Option ID = 37198]
2. 20% [Option ID = 37201]
3. 11.11% [Option ID = 37200]
4. 8.33% [Option ID = 37199]

25% [Option ID = 37198]

47)

[Question ID = 24264]

1. -1 [Option ID = 37054]
2. -1.5 [Option ID = 37057]
3. 1 [Option ID = 37055]
4. 1.5 [Option ID = 37056]

-1 [Option ID = 37054]

48)

[Question ID = 24268]

1. 1.8 A [Option ID = 37071]
2. 1.1 A [Option ID = 37070]
3. 3.2 A [Option ID = 37073]
4. 2.2 A [Option ID = 37072]

1.1 A [Option ID = 37070]

49)

[Question ID = 24262]

1. 15 Ω [Option ID = 37047]
2. 20 Ω [Option ID = 37046]
3. 5 Ω [Option ID = 37049]
4. 10 Ω [Option ID = 37048]

20 Ω [Option ID = 37046]

50)

[Question ID = 24283]

1. [Option ID = 37130]

2. [Option ID = 37133]

3. [Option ID = 37132]

4. [Option ID = 37131]

[Option ID = 37130]

51)

[Question ID = 24326]

1. 5.5 [Option ID = 37305]
2. 4.5 [Option ID = 37303]
3. 2.5 [Option ID = 37302]
4. 6.5 [Option ID = 37304]

2.5 [Option ID = 37302]

52)

[Question ID = 26451]

1. [Option ID = 45801]

2. [Option ID = 45799]

3. [Option ID = 45802]

4. [Option ID = 45800]

[Option ID = 45799]

53)

[Question ID = 24242]

1. [Option ID = 36967]

2. [Option ID = 36969]

3. [Option ID = 36968]

4. [Option ID = 36966]

[Option ID = 36966]

54)

[Question ID = 24247]

1. 31/90 [Option ID = 36988]
2. 23/30 [Option ID = 36986]
3. 19/60 [Option ID = 36989]
4. 11/20 [Option ID = 36987]

23/30 [Option ID = 36986]

55)

[Question ID = 24289]

1. 100 µF [Option ID = 37155]
2. 20 µF [Option ID = 37157]
3. 10.35 µF [Option ID = 37154]
4. 1 µF [Option ID = 37156]

10.35 µF [Option ID = 37154]

56)

[Question ID = 24246]

1. 3+j, 3-j, 5+j [Option ID = 36984]
2. 3, -1+3j, -1-3j [Option ID = 36985]
3. -6+5j, 3+j, 3-j [Option ID = 36983]
4. 3, 3+5j, 6-j [Option ID = 36982]

3, 3+5j, 6-j [Option ID = 36982]

57)

[Question ID = 24285]

1. 80 [Option ID = 37141]
2. 56 [Option ID = 37140]
3. 60 [Option ID = 37138]
4. 320 [Option ID = 37139]

60 [Option ID = 37138]

58)

[Question ID = 24325]

1. [Option ID = 37301]

2. [Option ID = 37300]

3. [Option ID = 37299]

4. [Option ID = 37298]

[Option ID = 37298]

59)

[Question ID = 24260]

1. [Option ID = 37039]

2. [Option ID = 37038]

3. [Option ID = 37041]

4. [Option ID = 37040]

[Option ID = 37038]

60)

[Question ID = 24299]

1. 2/7 [Option ID = 37195]
2. 9/17 [Option ID = 37196]
3. 1/5 [Option ID = 37197]
4. 1/6 [Option ID = 37194]

1/6 [Option ID = 37194]

61)

[Question ID = 24245]

1. [Option ID = 36978]

2. [Option ID = 36981]

3. [Option ID = 36979]

4. [Option ID = 36980]

[Option ID = 36978]

62)

[Question ID = 24332]

1. [Option ID = 37329]

2. [Option ID = 37326]

3. [Option ID = 37327]

4. [Option ID = 37328]

[Option ID = 37326]

63)

[Question ID = 24239]

1. 0 [Option ID = 36957]
2. 1 [Option ID = 36955]
3. 1/2 In 2 [Option ID = 36954]
4. In 2 [Option ID = 36956]

1/2 In 2 [Option ID = 36954]

64)

[Question ID = 24272]

1. 12×104 V [Option ID = 37086]

2. 15.9×104 V [Option ID = 37089]
3. 1.2×103 V [Option ID = 37088]
4. 1.5×103 V [Option ID = 37087]

12×104 V [Option ID = 37086]

65)

[Question ID = 24275]

1. 0 1 [Option ID = 37101]
2. 1 2 [Option ID = 37098]
3. 1 [Option ID = 37099]
4. Error [Option ID = 37100]

1 2 [Option ID = 37098]

66)

[Question ID = 24336]

1. 1.5 W [Option ID = 37345]
2. 1.04 W [Option ID = 37343]
3. 52.08 W [Option ID = 37344]
4. 2.2 W [Option ID = 37342]

2.2 W [Option ID = 37342]

67)

[Question ID = 24307]

1. [Option ID = 37229]

2. [Option ID = 37228]

3. [Option ID = 37227]

4. [Option ID = 37226]

[Option ID = 37226]

68)

[Question ID = 24258]

1. [Option ID = 37031]

2. [Option ID = 37030]

3. [Option ID = 37033]

4. [Option ID = 37032]

[Option ID = 37030]

69)

[Question ID = 24271]

1. 2.0 µF [Option ID = 37082]
2. 2.5 µF [Option ID = 37085]
3. 1.0 µF [Option ID = 37083]
4. 1.32 µF [Option ID = 37084]

2.0 µF [Option ID = 37082]

70)

[Question ID = 24274]

1. 0 1 2 3 [Option ID = 37097]
2. Error [Option ID = 37095]
3. P Q R S [Option ID = 37094]
4. 80 81 82 83 [Option ID = 37096]

P Q R S [Option ID = 37094]

71)

[Question ID = 24265]

1. [Option ID = 37059]

2. [Option ID = 37058]

3. [Option ID = 37060]

4. [Option ID = 37061]

[Option ID = 37058]

72)

[Question ID = 24250]

1. 0 [Option ID = 36998]
2. 9/17 [Option ID = 37001]
3. 1/9 [Option ID = 36999]
4. 2/7 [Option ID = 37000]

0 [Option ID = 36998]

73)

[Question ID = 24284]

1. [Option ID = 37134]

2. [Option ID = 37136]

3. [Option ID = 37135]

4. [Option ID = 37137]

[Option ID = 37134]

74)

[Question ID = 24254]

1. [Option ID = 37016]

2. [Option ID = 37015]

3. [Option ID = 37014]

4. [Option ID = 37017]

[Option ID = 37014]

75)

[Question ID = 24259]

1. [Option ID = 37034]

2. [Option ID = 37036]

3. [Option ID = 37037]

4. [Option ID = 37035]

[Option ID = 37034]

76)

[Question ID = 24253]

1. 2 [Option ID = 37012]
2. 1 [Option ID = 37013]
3. 3 [Option ID = 37011]
4. 4 [Option ID = 37010]

4 [Option ID = 37010]

77)

[Question ID = 24252]

1. [Option ID = 37008]

2. [Option ID = 37009]

3. [Option ID = 37006]

4. [Option ID = 37007]

[Option ID = 37006]

78)

[Question ID = 24338]

1. 4π x 10-4 [Option ID = 37350]
2. 4π x 10-2 [Option ID = 37352]
3. 3π x 10-2 [Option ID = 37353]
4. π x 10-2 [Option ID = 37351]

4π x 10-4 [Option ID = 37350]

79)

[Question ID = 24312]

1. [Option ID = 37247]

2. [Option ID = 37249]

3. [Option ID = 37248]

4. [Option ID = 37246]

[Option ID = 37246]

80)

[Question ID = 24237]

1. 2 [Option ID = 36947]
2. 1 [Option ID = 36948]
3. 3 [Option ID = 36949]
4. 4 [Option ID = 36946]

4 [Option ID = 36946]

81)

[Question ID = 24314]

1. [Option ID = 37253]

2. [Option ID = 37251]

3. [Option ID = 37256]

4. [Option ID = 37254]

[Option ID = 37251]

82)

[Question ID = 24291]

1. -112 A/cm2 [Option ID = 37165]
2. 112 A/cm2 [Option ID = 37163]
3. 1120 A/cm2 [Option ID = 37162]
4. -1120 A/cm2 [Option ID = 37164]

1120 A/cm2 [Option ID = 37162]

83)

[Question ID = 24255]

1. 0 [Option ID = 37018]
2. 0.5 [Option ID = 37020]
3. 1 [Option ID = 37019]
4. 0.2 [Option ID = 37021]

0 [Option ID = 37018]

84)

[Question ID = 24266]

1. T2=T [Option ID = 37064]
2. T-1=T [Option ID = 37063]
3. Determinant (T)=0 [Option ID = 37062]
4. Determinant (T)=1 [Option ID = 37065]

Determinant (T)=0 [Option ID = 37062]

85)

[Question ID = 24256]

1. [Option ID = 37022]

2. [Option ID = 37023]

3. [Option ID = 37024]
4. [Option ID = 37025]

[Option ID = 37022]

86)

[Question ID = 24341]

1. 56.25 Ω [Option ID = 37365]
2. 0 Ω [Option ID = 37364]
3. 100 Ω [Option ID = 37362]
4. 70 Ω [Option ID = 37363]

100 Ω [Option ID = 37362]

87) Consider sinusoidal modulation in an AM system. Assuming no over modulation , the modulation
index (µ) when the maximum and minimum values of the envelope, respectively, are 3V and 1V is
[Question ID = 24298]

1. 0.5 [Option ID = 37193]
2. 1 [Option ID = 37192]
3. 0.75 [Option ID = 37190]
4. 0.2 [Option ID = 37191]

0.75 [Option ID = 37190]

88) Consider a four bit Digital to Analog converter. The analog value corresponding to a digital signals of
values 0000 and 0001 are 0 volts and 0.0625 volts respectively. The analog value (in volts)
corresponding to the digital signal 1111 is [Question ID = 24273]

1. 0.9375 [Option ID = 37092]
2. 0.0241 [Option ID = 37090]
3. 2.5 [Option ID = 37093]
4. 0.543 [Option ID = 37091]

0.0241 [Option ID = 37090]

89) A series RLC circuit has a resonance frequency of 1 kHz and a quality factor Q = 100. If each of R, L
and C is doubled from its original value, the new Q of the circuit is

[Question ID = 24270]

1. 100 [Option ID = 37080]
2. 200 [Option ID = 37081]
3. 50 [Option ID = 37079]
4. 25 [Option ID = 37078]

25 [Option ID = 37078]

90) Integration of CAD and CAM is known as [Question ID = 24279]

1. CAD alone [Option ID = 37117]
2. CIM [Option ID = 37116]
3. CAM alone [Option ID = 37115]
4. CIE [Option ID = 37114]

CIE [Option ID = 37114]

91) A PCM system uses a uniform quantizer which has a range –V to +V and it is followed by a 7 bit
binary encoder. A zero mean signal applied to the quantizer extends over its entire range and has
uniform probability density. The ratio of the signal to the quantization noise power at the output of the
quantizer is (use log10 2=0.3)

[Question ID = 24308]

1. 42 dB [Option ID = 37231]
2. 14 dB [Option ID = 37230]
3. 28 dB [Option ID = 37233]
4. 56 dB [Option ID = 37232]

14 dB [Option ID = 37230]

92) The speed of conversion is maximum in [Question ID = 24282]

1. successive – approximation A/D converter [Option ID = 37127]
2. parallel-comparative A/D converter [Option ID = 37126]
3. counter ramp A/D converter [Option ID = 37128]
4. dual-slop A/D converter [Option ID = 37129]

parallel-comparative A/D converter [Option ID = 37126]

93) A mixer stage has a noise figure of 20 dB. This mixer stage is preceded by an amplifier which has a
noise figure of 10 dB and an available power gain of 20 dB. The overall noise figure at the input is
[Question ID = 24339]

1. 15 [Option ID = 37354]
2. 30 [Option ID = 37357]
3. 19.5 [Option ID = 37355]
4. 10.99 [Option ID = 37356]

15 [Option ID = 37354]

94) A lossless transmission line of length 50 cm with L = 10 µH/m, C = 40 pF/m is operated at 25 MHz.
Its electrical path length is

[Question ID = 24327]

1. 180 degrees [Option ID = 37306]
2. λ meters [Option ID = 37308]
3. 0.5 meters [Option ID = 37309]
4. π/2 radians [Option ID = 37307]

180 degrees [Option ID = 37306]

95) A microprogram is [Question ID = 24281]

1. usually written in high level language [Option ID = 37122]
2. a program for microcomputer [Option ID = 37124]
3. a program written in assembly language [Option ID = 37125]
4. a sequencing program for the control unit of any processor [Option ID = 37123]

usually written in high level language [Option ID = 37122]

96) It is given that y’’+2y’+y=0, y(0)=0, y(1)=0. What is y(0.5) ? [Question ID = 24241]

1. 0 [Option ID = 36962]
2. 1.13 [Option ID = 36965]
3. 0.62 [Option ID = 36964]

4. 0.37 [Option ID = 36963]

0 [Option ID = 36962]

97) Dynamic memory cells are constructed using [Question ID = 24278]

1. Transistors [Option ID = 37110]
2. JFETs [Option ID = 37113]
3. MOSFETs [Option ID = 37111]
4. Flip-flops [Option ID = 37112]

Transistors [Option ID = 37110]

98) A particular green LED emits light of wavelength 5490 Å. The energy bandgap of the semiconductor
material used there is [Question ID = 24287]

1. 2.26 eV [Option ID = 37148]
2. 1.17 eV [Option ID = 37149]
3. 1.98 eV [Option ID = 37146]
4. 0.74 eV [Option ID = 37147]

1.98 eV [Option ID = 37146]

99) Three light bulbs are chosen at random from 15 bulbs of which 5 are defective. The probability that
exactly one is defective, is [Question ID = 24251]

1. 3/17 [Option ID = 37002]
2. 45/91 [Option ID = 37003]
3. 2/7 [Option ID = 37004]
4. 92/71 [Option ID = 37005]

3/17 [Option ID = 37002]

100) A voltage of 6 V is applied across a 2 cm long semiconductor bar. The average drift velocity is 104
cm/sec. The electron mobility is [Question ID = 24290]

1. 3333 cm2/V-s [Option ID = 37159]
2. 4396 cm2/V-s [Option ID = 37160]
3. 6×104 cm2/V-s [Option ID = 37158]
4. 3×104 cm2/V-s [Option ID = 37161]

6×104 cm2/V-s [Option ID = 37158]