q

Delhi University Entrance Test (DUET) 2020 Previous Year Question Paper With Answer Key

DU MTech Microwave Electronics
Topic: ME MTECH S2
1) A family of arcs is obtained in the Smith chart by varying normalized reactance in a range of,
[Question ID = 4165]
1. 0 to 1 [Option ID = 16654]
2. to + [Option ID = 16655]
3. 0 to + [Option ID = 16656]
4. 1 to 0 [Option ID = 16657]
Correct Answer :
to + [Option ID = 16655]
2) A 75 quarter wave transformer is connected to a 125 TV receiver. The impedance at the input of this transformer
will be,
[Question ID = 4166]
1. 25 [Option ID = 16658]
2. 45 [Option ID = 16659]
3. 75 [Option ID = 16660]
4. 100 [Option ID = 16661]
Correct Answer :
45 [Option ID = 16659]
3) If a coaxial line has dimensions a ? b cm, the conductivity of the conductors is and the permittivity of the filled
medium is . Conductance per unit length of this coaxial transmission line is given as,
[Question ID = 4167]
1.
[Option ID = 16662]
2.
[Option ID = 16663]
3.
[Option ID = 16664]
4.
[Option ID = 16665]
Correct Answer :
[Option ID = 16662]
4) A lossless transmission line used in a TV Receiver has a capacitance of 50 pF/m and an inductance of 20 nH/m. The
characteristic impedence of a 10 meter long line will be then,
[Question ID = 4168]
1. 50 [Option ID = 16666]
2. 20 [Option ID = 16667]
3. 40 [Option ID = 16668]
4. 100 [Option ID = 16669]
Correct Answer :
20 [Option ID = 16667]
5) A onehalf wavelength lossless line of 50 is terminated to a load impedence of 50+j50, its input impedance is,
[Question ID = 4169]
1. 50+j50 [Option ID = 16670]
2. 50j50 [Option ID = 16671]
3. 25+j25 [Option ID = 16672]
4. 25j25 [Option ID = 16673]
Correct Answer :
50+j50 [Option ID = 16670]

---

6) If a transmission line of characteristic impedance Z is connected to a load of impedance Z
0
, then
L
at a distance d is
equal to,
[Question ID = 4170]
1.
[Option ID = 16674]
2.
[Option ID = 16675]
3.
[Option ID = 16676]
4.
[Option ID = 16677]
Correct Answer :
[Option ID = 16677]
7) A copper rectangular cavity resonator is structured by 3x4x1 cm . The resonant frequency for TM
3
mode, is
110
[Question ID = 4171]
1. 6.25 GHz [Option ID = 16678]
2. 5.81 GHz [Option ID = 16679]
3. 8.65 GHz [Option ID = 16680]
4. 2.04 GHz [Option ID = 16681]
Correct Answer :
6.25 GHz [Option ID = 16678]
8) A transmission line of characteristics impedance Z0 is terminated in a load having VSWR=2. The normalized load

impedance z of
n
the

transmission

line

is

[Question ID = 4172]
1. Z
0 [Option ID = 16682]
2. 1 [Option ID = 16683]
3. 0 [Option ID = 16684]
4. 2 [Option ID = 16685]
Correct Answer :
2 [Option ID = 16685]
9) In a Square coaxial transmission line shown in Fig., if the space between the conductors is filled with a material having a
relative permittivity of 4.0 and the capacitance per unit length is 6.3 F/m, the characteristic impedance of this line will
be,
[Question ID = 4173]
1. 30 [Option ID = 16686]
2. 50 [Option ID = 16687]
3. 40 [Option ID = 16688]
4. 20 [Option ID = 16689]
Correct Answer :
30 [Option ID = 16686]

---

10) A parabolic antenna is operating at 5 GHz and has an antenna power gain of 216. The diameter of this antenna is
[Question ID = 4174]
1. 49 cm [Option ID = 16690]
2. 16 cm [Option ID = 16691]
3. 25 cm [Option ID = 16692]
4. 36 cm [Option ID = 16693]
Correct Answer :
36 cm [Option ID = 16693]
11) If a signal of 30 MHz is transmitted through a coaxial cable, which has a capacitance of 40 pF/m and an inductance of
900 nH/m. The propagation velocity for a 1m long cable is given by,
[Question ID = 4175]
1. 2.36?10 m/s
8
[Option ID = 16694]
2. 1.66?10 m/s
8
[Option ID = 16695]
3. 2.66?10 m/s
8
[Option ID = 16696]
4. 1.33?10 m/s
8
[Option ID = 16697]
Correct Answer :
1.66?10 m/s
8
[Option ID = 16695]
12) A perpendicularly polarized wave is incident at an angle of

o



i =15 and it is propagating from medium 1 to medium 2.
Medium 1 is characterized by = 9,
r1
= 1
r1

,
= 0 and medium 2 is a free space. If the electric field intensity E
1
i = 3.0
mV/m, the value of the magnetic field intensity H , will be,
i
[Question ID = 4176]
1. 23.87 A/m
[Option ID = 16698]
2. 48.53 A/m
[Option ID = 16699]
3. 15.46 A/m
[Option ID = 16700]
4. 10 A/m
[Option ID = 16701]
Correct Answer :
23.87 A/m
[Option ID = 16698]
13) If capacitor plates of area `A' are placed `d' distance apart and the capacitor is filled with a material having dielectric
constant , then the current through this capacitor is expressed as,
[Question ID = 4177]
1.
[Option ID = 16702]
2.
[Option ID = 16703]
3.
[Option ID = 16704]
4.
[Option ID = 16705]
Correct Answer :
[Option ID = 16704]

---

14) A wave with a frequency of 100 MHz is propagating in a free Space, the propagation constant of this wave will be,
[Question ID = 4178]
1. j 3.14 [Option ID = 16706]
2. j 5.53 [Option ID = 16707]
3. j 2.09 [Option ID = 16708]
4. j 10.8 [Option ID = 16709]
Correct Answer :
j 2.09 [Option ID = 16708]
15) A transmission line of characteristic impedance Z terminated by a load R= (1/2)Z
0
0 as shown in Fig., is connected to a
matched source by a switch for a short time t to produce a pulse on the line.
If the propagation time along the line is T, where T > t, the values of the reflection coefficient at point A and point B are,
respectively
[Question ID = 4179]
1. 1, 1/3 [Option ID = 16710]
2. 1, 1 [Option ID = 16711]
3. 2, 1 [Option ID = 16712]
4. 1/2, 1/2 [Option ID = 16713]
Correct Answer :
1, 1/3 [Option ID = 16710]
16) A /4 transformer is connected in between generator and load, which have impedence ratio Z / Z
L
G =0.16 and Z =
G
50 .The characteristic impedance of a /4 transformer is
[Question ID = 4180]
1. 8
[Option ID = 16714]
2. 20
[Option ID = 16715]
3. 312
[Option ID = 16716]
4. 25
[Option ID = 16717]
Correct Answer :
20
[Option ID = 16715]
17) The input power needed to generate an output power of 3 W from an amplifier with a power gain of 30 dB is
[Question ID = 4181]
1. 1 W [Option ID = 16718]
2. 100 mW [Option ID = 16719]
3. 1 mW [Option ID = 16720]
4. 3 mW [Option ID = 16721]
Correct Answer :
3 mW [Option ID = 16721]
18) The VSWR of a coaxial line which has a reflection coefficient of
, is
[Question ID = 4182]
1. 4
[Option ID = 16722]
2. 1
[Option ID = 16723]
3. 1.6
[Option ID = 16724]
4. 2

---

[Option ID = 16725]
Correct Answer :
4
[Option ID = 16722]
19) When EM waves travel along a metallic waveguide in which there is a discontinuity due to some lossy material filled in
a small length and the other end is terminated with a matched load. The discontinuity will cause
[Question ID = 4183]
1. Progressive waves throughout the line. [Option ID = 16726]
2. Progressive waves on the generator side and standing waves on the matched load side. [Option ID = 16727]
3. Standing waves on the generator side and progressive waves on the matched load side. [Option ID = 16728]
4. Standing waves thoughout the line. [Option ID = 16729]
Correct Answer :
Standing waves on the generator side and progressive waves on the matched load side. [Option ID = 16728]
20) The power output of an input power of 10 mW in the following system, is

[Question ID = 4184]
1. 5 dBm [Option ID = 16730]
2. 10 dB [Option ID = 16731]
3. 0 dBm [Option ID = 16732]
4. 10 dBm [Option ID = 16733]
Correct Answer :
0 dBm [Option ID = 16732]
21) At microwave frequency, hybrid(H), admittance (Y) and impedance (Z) parameters can not be measured because,
[Question ID = 4185]
1. Short and open circuit conditions are realizable over broad frequency range. [Option ID = 16734]
2. Short and open circuit conditions are unrealizable over broad frequency range. [Option ID = 16735]
3. Only short circuit condition is realizable over broad frequency range. [Option ID = 16736]
4. Only open circuit condition Is realizable over broad frequency range. [Option ID = 16737]
Correct Answer :
Short and open circuit conditions are unrealizable over broad frequency range. [Option ID = 16735]
22) Noise temperature (T) and gain(G) are two important parameters of satellite antenna. Out of the following,the antenna
having largest G/T ratio is
[Question ID = 4186]
1. Cassegrain antenna [Option ID = 16738]
2. Pyramidal antenna [Option ID = 16739]
3. Parabolic reflector [Option ID = 16740]
4. Dipole antenna [Option ID = 16741]
Correct Answer :
Parabolic reflector [Option ID = 16740]
23) A generator of 50 internal impedance and operating frequency of 1 GHz feeds a 75 load via a coaxial line of
characteristics impedance 50 . The reflection coefficient on the feed line is,
[Question ID = 4187]
1. 0.2 [Option ID = 16742]
2. 0.67 [Option ID = 16743]
3. 1.5 [Option ID = 16744]
4. 1.05 [Option ID = 16745]
Correct Answer :
0.2 [Option ID = 16742]
24) A lossless transmission line is excited by a signal of voltage 50o V at 1.2 MHz. If the line is terminated by Z ( = Z
L
) at
o
a distance 1km, the electrical length at the end point of the line is
[Question ID = 4188]
1. 4
[Option ID = 16746]
2. 6
[Option ID = 16747]

---

3. 8
[Option ID = 16748]
4. 2
[Option ID = 16749]
Correct Answer :
8
[Option ID = 16748]
25) The modulated microwave signal with 1 kHz square wave modulating signal is detected by
[Question ID = 4189]
1. Tunable detector [Option ID = 16750]
2. VSWR meter [Option ID = 16751]
3. Spectrum analyzer [Option ID = 16752]
4. Slotted line [Option ID = 16753]
Correct Answer :
Tunable detector [Option ID = 16750]
26) A parabolic dish has a gain of 40 dB at 3GHz. The diameter of this dish is
[Question ID = 4190]
1. 4.08 m [Option ID = 16754]
2. 8.02 m [Option ID = 16755]
3. 3.04 m [Option ID = 16756]
4. 1.25 m [Option ID = 16757]
Correct Answer :
4.08 m [Option ID = 16754]
27) A satellite operates with 12 GHz at a distance of 36000 km has effective isotropic radiated power (EIRP) of 20 dBW.The
flux density at receiving antenna of each station is
[Question ID = 4191]
1. 2.21 ? 10
W/m
14
2 [Option ID = 16758]
2. 3.6 x 10
W/m
14
2 [Option ID = 16759]
3. 0.614 ? 10
W/m
14
2 [Option ID = 16760]
4. 2.0 ? 10
W/m
14
2 [Option ID = 16761]
Correct Answer :
0.614 ? 10
W/m
14
2 [Option ID = 16760]
28) A broadside array operating at 100cm wavelength consist of 4 halfwave dipoles spaced 50cm apart. Each element
carries radio frequency current In the same phase and of magnitude 0.5 A. The radiated power will be
[Question ID = 4192]
1. 34 W
2
[Option ID = 16762]
2. 16 W
2
[Option ID = 16763]
3. 20 W
2
[Option ID = 16764]
4. 50 W
2
[Option ID = 16765]
Correct Answer :
20 W
2
[Option ID = 16764]
29) Charge needed within a unit sphere centred at the origin for producing a potential field, V = 6r /
5

0 for the distance r
1 meter, is
[Question ID = 4193]
1. 30 Coulomb
[Option ID = 16766]
2. 240 Coulomb
[Option ID = 16767]
3. 120 Coulomb
[Option ID = 16768]
4. 180 Coulomb
[Option ID = 16769]
Correct Answer :
120 Coulomb
[Option ID = 16768]
30) A material has conductivity of 10 mho/m and a relative permittivity of 4.The frequency for which conduction current
2

---

in the medium is equal to displacement current is
[Question ID = 4194]
1. 90 MHz [Option ID = 16770]
2. 180 MHz [Option ID = 16771]
3. 27 MHz [Option ID = 16772]
4. 45 MHz [Option ID = 16773]
Correct Answer :
45 MHz [Option ID = 16773]
31) For a electricity short dipole of length 80 cm operating at 30 MHz, the loss resistance (R
) is 1.5 . Its radiation
loss
efficiency is
[Question ID = 4195]
1. 92.4 %
[Option ID = 16774]
2. 94.9 %
[Option ID = 16775]
3. 102.5 %
[Option ID = 16776]
4. 86.7 %
[Option ID = 16777]
Correct Answer :
94.9 %
[Option ID = 16775]
32) A Hertzien dipole of length /50 has an efficiency of 6.5%. The total quality factor for this dipole is
[Question ID = 4196]
1. 1
[Option ID = 16778]
2. 0.20
[Option ID = 16779]
3. 7
[Option ID = 16780]
4. 5.5
[Option ID = 16781]
Correct Answer :
0.20
[Option ID = 16779]
33) The value of integral
is given by
[Question ID = 4197]
1. 8/3
[Option ID = 16782]
2. 4/3
[Option ID = 16783]
3. 1/2
[Option ID = 16784]
4. 2/3
[Option ID = 16785]
Correct Answer :
4/3
[Option ID = 16783]
34) The region specified by
in cylindrical coordinates has volume of
[Question ID = 4198]
1. 4.712

---

[Option ID = 16786]
2. 2.712
[Option ID = 16787]
3. 2.725
[Option ID = 16788]
4. 5.725
[Option ID = 16789]
Correct Answer :
4.712
[Option ID = 16786]
35) With the initial condition
the solution of the differential equation,
is
[Question ID = 4199]
1.
[Option ID = 16790]
2.
[Option ID = 16791]
3.
[Option ID = 16792]
4.
[Option ID = 16793]
Correct Answer :
[Option ID = 16790]
36) The Newton Raphson method is used to solve the equation f(x) = x 5x
3
+ 6x 8 = 0. Taking the initial guess as x =
2
5, the solution obtained at the end of the first iteration is
[Question ID = 4200]
1. 2.2903
[Option ID = 16794]
2. 4.515
[Option ID = 16795]
3. 4.2903
[Option ID = 16796]
4. 2.515
[Option ID = 16797]
Correct Answer :
4.2903
[Option ID = 16796]
37) The inverse Laplace transform of the function
is equal to
[Question ID = 4201]
1. 2e + e
t
3t
[Option ID = 16798]
2. e + 2e
t
3t
[Option ID = 16799]
3. e 2e
t
3t
[Option ID = 16800]
4. 2e e
t
3t
[Option ID = 16801]
Correct Answer :
2e e
t
3t

---

[Option ID = 16801]
38) A 4 GHz carrier is DSB SC modulated by a lowpass message signal is to be ideally sampled. The minimum frequency of
the sampling impulse train should be
[Question ID = 4202]
1. 4 MHz
[Option ID = 16802]
2. 8 GHz
[Option ID = 16803]
3. 4 GHz
[Option ID = 16804]
4. 8 MHz
[Option ID = 16805]
Correct Answer :
8 MHz
[Option ID = 16805]
39) A message signal given by
is amplitudemodulated with a carrier of frequency
to generate
.
What is the power efficiency achieved by this modulation scheme?
[Question ID = 4203]
1. 20%
[Option ID = 16806]
2. 11.11%
[Option ID = 16807]
3. 8.33%
[Option ID = 16808]
4. 25%
[Option ID = 16809]
Correct Answer :
20%
[Option ID = 16806]
40) The number of quantization levels with 8bits required to reduce the quantization noise by a factor of 4 would be
[Question ID = 4204]
1. 1024 [Option ID = 16810]
2. 64 [Option ID = 16811]
3. 256 [Option ID = 16812]
4. 512 [Option ID = 16813]
Correct Answer :
512 [Option ID = 16813]
41) An ideal band pass channel 500 Hz 2000 Hz is deployed for communication. A modem is designed to transmit bits at
the rate of 4800 bits/s using 16 QAM. The roll off factor of a pulse with a raised cosine spectrum that utilizes the entire
frequency band is
[Question ID = 4205]
1. 0.20
[Option ID = 16814]
2. 0.25
[Option ID = 16815]
3. 0.30
[Option ID = 16816]
4. 0.15
[Option ID = 16817]
Correct Answer :
0.25
[Option ID = 16815]

---

42) The Nyquist sampling frequency for the signal
is given by
[Question ID = 4206]
1. 1200 Hz
[Option ID = 16818]
2. 400 Hz
[Option ID = 16819]
3. 600 Hz
[Option ID = 16820]
4. 1400 Hz
[Option ID = 16821]
Correct Answer :
1200 Hz
[Option ID = 16818]
43) The Vestigial Side Band (VSB) modulation is preferred in TV systems because It reduces the bandwidth requirement to
half it avoids phase distortion at low frequency
[Question ID = 4207]
1. 1 only
[Option ID = 16822]
2. 2 only
[Option ID = 16823]
3. Neither 1 nor 2
[Option ID = 16824]
4. Both 1 and 2
[Option ID = 16825]
Correct Answer :
Neither 1 nor 2
[Option ID = 16824]
44) A communication channel distributed by Gaussian noise has a bandwidth of 6 kHz and S/N ratio of 15.The maximum
transmission rate that such a channel can support is
[Question ID = 4208]
1. 48 kbits/s [Option ID = 16826]
2. 24 kbits/sec [Option ID = 16827]
3. 2.4 kbits/s [Option ID = 16828]
4. 32 kbits/s [Option ID = 16829]
Correct Answer :
24 kbits/sec [Option ID = 16827]
45) In the given circuit,the value of V is
x
[Question ID = 4209]
1. 12 V
[Option ID = 16830]
2. 10 V
[Option ID = 16831]
3. 0.8 V

---

[Option ID = 16832]
4. 8 V
[Option ID = 16833]
Correct Answer :
8 V
[Option ID = 16833]
46) In the circuit shown,the current I flowing through the 50 resistor will be zero if the value of Capacitor C (in F) is
[Question ID = 4210]
1. 15 F
[Option ID = 16834]
2. 20 F
[Option ID = 16835]
3. 10 F
[Option ID = 16836]
4. 22.5 F
[Option ID = 16837]
Correct Answer :
20 F
[Option ID = 16835]
47) In the circuit shown, the initial voltages across the capacitors C1 and C are 1V and 3V, respectively. The switch is
2
closed at time t = 0. The total energy dissipated (in Joules) in the resistor R until steady state is reached, is
[Question ID = 4211]
1. 1.5 J
[Option ID = 16838]
2. 1.0 J
[Option ID = 16839]
3. 0.5 J
[Option ID = 16840]
4. 2 J
[Option ID = 16841]
Correct Answer :
1.5 J
[Option ID = 16838]
48)
The component values are

---

[Question ID = 4212]
1. L = 0.1 H, R = 0.5 , C = 5 F
[Option ID = 16842]
2. L = 5 H, R = 0.5 , C = 0.1 F
[Option ID = 16843]
3. L = 0.1 H, R = 2 ,C = 5 F
[Option ID = 16844]
4. L = 5H, R = 2 , C = 0.1 F
[Option ID = 16845]
Correct Answer :
L = 0.1 H, R = 2 ,C = 5 F
[Option ID = 16844]
49) In the following graph,the number of trees (P) and the number number of cut sets (Q)are
[Question ID = 4213]
1. P = 2,Q = 6 [Option ID = 16846]
2. P = 2,Q = 2 [Option ID = 16847]
3. P = 4,Q = 6 [Option ID = 16848]
4. P = 4,Q = 10 [Option ID = 16849]
Correct Answer :
P = 4,Q = 6 [Option ID = 16848]
50)
[Question ID = 4214]
1.
[Option ID = 16850]
2.
[Option ID = 16851]
3.
[Option ID = 16852]
4.
[Option ID = 16853]
Correct Answer :
[Option ID = 16853]
51) If,
and
. Then the value of x is
[Question ID = 4215]
1. 1/3
[Option ID = 16854]
2. 1/2
[Option ID = 16855]
3. 1/6
[Option ID = 16856]
4. 1
[Option ID = 16857]

---

Correct Answer :
1/3
[Option ID = 16854]
52) The minimum value of
[Question ID = 4216]
1. 45
[Option ID = 16858]
2. 50
[Option ID = 16859]
3. 25
[Option ID = 16860]
4. 75
[Option ID = 16861]
Correct Answer :
75
[Option ID = 16861]
53)
is equal to
[Question ID = 4217]
1.
[Option ID = 16862]
2.
[Option ID = 16863]
3.
[Option ID = 16864]
4.
[Option ID = 16865]
Correct Answer :
[Option ID = 16865]
54) A box contains 5 black and 5 red balls.Two balls are randomly picked one after another from the box, without
replacement.The probability for balls being red is
[Question ID = 4218]
1. 2/9 [Option ID = 16866]
2. 2/5 [Option ID = 16867]
3. 1/2 [Option ID = 16868]
4. 1/7 [Option ID = 16869]
Correct Answer :
2/9 [Option ID = 16866]
55) The value of
by using onesegment trapezoidal rule is most nearly
[Question ID = 4219]
1. 11.672
[Option ID = 16870]
2. 43.729
[Option ID = 16871]
3. 24.119
[Option ID = 16872]
4. 31.807
[Option ID = 16873]
Correct Answer :
43.729
[Option ID = 16871]

---

56) If the arithmetic mean of two numbers is 10 and their geometric mean is 8, the numbers are
[Question ID = 4220]
1. 24, 5
[Option ID = 16874]
2. 14, 7
[Option ID = 16875]
3. 8, 11
[Option ID = 16876]
4. 16, 4
[Option ID = 16877]
Correct Answer :
16, 4
[Option ID = 16877]
57) A random process is defined by X (t) = A where A is continous random variable uniformly distributed on (0,2). The auto
correlation function and mean of the process are
[Question ID = 4221]
1. 1/2 and 1/3
[Option ID = 16878]
2. 1/3 and 3
[Option ID = 16879]
3. 1/2 and 1
[Option ID = 16880]
4. 8/3 and 2
[Option ID = 16881]
Correct Answer :
8/3 and 2
[Option ID = 16881]
58) The density function of two random variable X and Y is



The expected value of the function g( x, y) =
is
[Question ID = 4222]
1. 96
[Option ID = 16882]
2. 32
[Option ID = 16883]
3. 48
[Option ID = 16884]
4. 128
[Option ID = 16885]
Correct Answer :
128
[Option ID = 16885]
59) The radiation resistance of an infinitesimal dipole of overall length l= /40 is
[Question ID = 4223]
1. 2 [Option ID = 16886]
2. 50 [Option ID = 16887]
3. 0.493 [Option ID = 16888]
4. O.316 [Option ID = 16889]
Correct Answer :
0.493 [Option ID = 16888]

---

60) The Nyquist sampling rate for the signal gt= 10 cos50t cos2100t where 't' is in seconds, is
[Question ID = 4224]
1. 150 samples per second
[Option ID = 16890]
2. 300 samples per second
[Option ID = 16891]
3. 250 samples per second
[Option ID = 16892]
4. 200 samples per second
[Option ID = 16893]
Correct Answer :
250 samples per second
[Option ID = 16892]
61) In a PCM system, if the code word length is increased from 6 to 10 bits, the signal to quantization noise ratio improves
by the factor.
[Question ID = 4225]
1. 512
[Option ID = 16894]
2. 128
[Option ID = 16895]
3. 64
[Option ID = 16896]
4. 256
[Option ID = 16897]
Correct Answer :
256
[Option ID = 16897]
62) In C language,what is the output of the following code
int main ()
{
int a = 1, b = 9, c; c = a == b; printf("%i" ,c);
}
[Question ID = 4226]
1. 4
[Option ID = 16898]
2. 0
[Option ID = 16899]
3. 1
[Option ID = 16900]
4. Error
[Option ID = 16901]
Correct Answer :
0
[Option ID = 16899]
63) In C language,what is the output of the following code
int main ()
{
int a = 63, b = 9 ;
printf( "%d",a>>a/b2);
}

---

[Question ID = 4227]
1. 0
[Option ID = 16902]
2. 2
[Option ID = 16903]
3. 3
[Option ID = 16904]
4. 1
[Option ID = 16905]
Correct Answer :
1
[Option ID = 16905]
64) The decimal equivalent of hex number 1A53 is
[Question ID = 4228]
1. 6793 [Option ID = 16906]
2. 6973 [Option ID = 16907]
3. 6379 [Option ID = 16908]
4. 6739 [Option ID = 16909]
Correct Answer :
6739 [Option ID = 16909]
65) A TDM link has 20 signal channels and each channel is sampled 8000 times/sec. Each sample is represented by seven
binary bits and contains an additional bit for synchronization.The total bit rate for the TDM link is
[Question ID = 4229]
1. 1280 K bits/sec
[Option ID = 16910]
2. 1180 K bits/sec
[Option ID = 16911]
3. 1280 M bits/sec
[Option ID = 16912]
4. 1180 M bits/sec
[Option ID = 16913]
Correct Answer :
1280 K bits/sec
[Option ID = 16910]
66) The analog output voltage(V ) of 6bit digitaltoanalog converter(R2R ladder network) with V
0
as 7V, when the
ref
digital input is 011100 is
[Question ID = 4230]
1. 4.65 V
[Option ID = 16914]
2. 8 V
[Option ID = 16915]
3. 7.75 V
[Option ID = 16916]
4. 3.06 V
[Option ID = 16917]
Correct Answer :
3.06 V
[Option ID = 16917]
67) If a tuned collector oscillator in a radio receiver has a fixed inductance of 50 H and has to be tuneable over the
frequency band of 600 to 1000 kHz, then the range of variable capacitor to be used is
[Question ID = 4231]
1. 2576 pF to 250 pF
[Option ID = 16918]
2. 5000 pF to 760 pF

---

[Option ID = 16919]
3. 1410 pF to 507 pF
[Option ID = 16920]
4. 3500 pF to 150 pF
[Option ID = 16921]
Correct Answer :
1410 pF to 507 pF
[Option ID = 16920]
68) If current gain of a transistor in CE mode is 48 then its common base current gain and the base current when the
emitter current is 5mA are
[Question ID = 4232]
1. 0.98 and 1.0 x 10 A
4
[Option ID = 16922]
2. 0.99 and 2.5 x 10 A
4
[Option ID = 16923]
3. 0.97 and 1.2 x 105 A [Option ID = 16924]
4. 0.90 and 1.5 x 10 A
4
[Option ID = 16925]
Correct Answer :
0.98 and 1.0 x 10 A
4
[Option ID = 16922]
69) An N channel JFET requires a series resistor R to self bias with I
s
DSS = 6V.The value of this resistor is
[Question ID = 4233]
1. 166 [Option ID = 16926]
2. 18.2 [Option ID = 16927]
3. 83.25 [Option ID = 16928]
4. 333 [Option ID = 16929]
Correct Answer :
333 [Option ID = 16929]
70) In which of the following diodes,the width of the junction barrier is very high
[Question ID = 4234]
1. Photo diode [Option ID = 16930]
2. PIN diode [Option ID = 16931]
3. Schottky diodes [Option ID = 16932]
4. Tunnel diode [Option ID = 16933]
Correct Answer :
PIN diode [Option ID = 16931]
71) The sensitivity of photo diode depends on
[Question ID = 4235]
1. Depletion region width and excess carrier lifetime [Option ID = 16934]
2. Excess carrier life time and forward bias current [Option ID = 16935]
3. Forward bias current and light intensity [Option ID = 16936]
4. Light intensity and depletion region width [Option ID = 16937]
Correct Answer :
Light intensity and depletion region width [Option ID = 16937]
72)
[Question ID = 4236]
1. 4 [Option ID = 16938]
2.
[Option ID = 16939]
3.
[Option ID = 16940]
4.
[Option ID = 16941]
Correct Answer :
[Option ID = 16939]

---

73) If
is the Fourier transform of
, then Fourier transform of
is
[Question ID = 4237]
1.
[Option ID = 16942]
2.
[Option ID = 16943]
3.
[Option ID = 16944]
4.
[Option ID = 16945]
Correct Answer :
[Option ID = 16944]
74) The intercepts made by the plane 3x + 4y + 2z 12 = 0 on the coordinate axes are
[Question ID = 4238]
1. (4,3,6) [Option ID = 16946]
2. (0,1,0) [Option ID = 16947]
3. (1,1,1) [Option ID = 16948]
4. (1,0,1) [Option ID = 16949]
Correct Answer :
(4,3,6) [Option ID = 16946]
75) The solution of
=
[Question ID = 4239]
1.
[Option ID = 16950]
2.
[Option ID = 16951]
3.
[Option ID = 16952]
4.
[Option ID = 16953]
Correct Answer :
[Option ID = 16953]
76) The argument of the complex number
is
[Question ID = 4240]
1.
[Option ID = 16954]
2.
[Option ID = 16955]
3.
[Option ID = 16956]
4.
[Option ID = 16957]
Correct Answer :

---

[Option ID = 16956]
77)
[Question ID = 4241]
1.
[Option ID = 16958]
2.
[Option ID = 16959]
3.
[Option ID = 16960]
4.
[Option ID = 16961]
Correct Answer :
[Option ID = 16961]
78) Let
and
then
[Question ID = 4242]
1.
[Option ID = 16962]
2.
[Option ID = 16963]
3.
[Option ID = 16964]
4.
[Option ID = 16965]
Correct Answer :
[Option ID = 16964]
79) store data or information temporarily and pass it on as directed by the control unit
[Question ID = 4243]
1. address [Option ID = 16966]
2. register [Option ID = 16967]
3. number [Option ID = 16968]
4. memory [Option ID = 16969]
Correct Answer :
register [Option ID = 16967]
80) Working of the WAN generally involves
[Question ID = 4244]
1. ATM [Option ID = 16970]
2. frame delay [Option ID = 16971]
3. user agent [Option ID = 16972]
4. satellite [Option ID = 16973]
Correct Answer :
satellite [Option ID = 16973]
81) Positive AND gate is also a negative
[Question ID = 4245]
1. NOR gate [Option ID = 16974]
2. NAND gate [Option ID = 16975]
3. NOR gate [Option ID = 16976]

---

4. OR gate [Option ID = 16977]
Correct Answer :
OR gate [Option ID = 16977]
82) What is the output of the following code?
#include < iostream.h >
void main ()
{
int main ;
main = 100 ;
count << main ++<< endl;
}
[Question ID = 4246]
1. Error : one cannot use main as identifier
[Option ID = 16978]
2. 100
[Option ID = 16979]
3. 101
[Option ID = 16980]
4. None of these
[Option ID = 16981]
Correct Answer :
100
[Option ID = 16979]
83) What is the output of the following code?
#include< iostream.h>
Void main()
{
bool a = 10 ;
count
}
[Question ID = 4247]
1. error
[Option ID = 16982]
2. false
[Option ID = 16983]
3. 10
[Option ID = 16984]
4. 1
[Option ID = 16985]
Correct Answer :
1
[Option ID = 16985]
84) A transmission line of characteristic impedance of 50 is terminated by a load impedance of (100 j50 ) and is fed
by a matched generator.The measured voltage amplitude at the load terminal is 100 V. The VSWR on the line is
[Question ID = 4248]
1. 1.583 [Option ID = 16986]
2. 2.562 [Option ID = 16987]
3. 2.618 [Option ID = 16988]
4. 1.684 [Option ID = 16989]
Correct Answer :
2.618 [Option ID = 16988]

---

85) When a transmission line has a load impedance same as that of the characteristic impedance,the line said to be
[Question ID = 4249]
1. Perpendicular [Option ID = 16990]
2. Polarized [Option ID = 16991]
3. Parallel [Option ID = 16992]
4. Matched [Option ID = 16993]
Correct Answer :
Matched [Option ID = 16993]
86) The characteristics impedance of a quarter wave line is 50 and load impedance of 20 ,the input impedance to this
transformer is
[Question ID = 4250]
1. 50 [Option ID = 16994]
2. 125 [Option ID = 16995]
3. 25 [Option ID = 16996]
4. 150 [Option ID = 16997]
Correct Answer :
125 [Option ID = 16995]
87) The minimum impedance of a transmission line is 75 with SWR 4 is
[Question ID = 4251]
1. 19.86 [Option ID = 16998]
2. 18.75 [Option ID = 16999]
3. 16.34 [Option ID = 17000]
4. 14.44 [Option ID = 17001]
Correct Answer :
18.75 [Option ID = 16999]
88) The power reflected in a transmission line, when its reflection coefficient and input power are 0.45 and 18W
[Question ID = 4252]
1. 3.645 W [Option ID = 17002]
2. 4.563 W [Option ID = 17003]
3. 2.50 W [Option ID = 17004]
4. 5.368 W [Option ID = 17005]
Correct Answer :
3.645 W [Option ID = 17002]
89) Diffusion constants Dp ,

Dn and mobility

?P and

?n and absolute temperature T are related as
[Question ID = 4253]
1.
[Option ID = 17006]
2.
[Option ID = 17007]
3.
[Option ID = 17008]
4.
[Option ID = 17009]
Correct Answer :
[Option ID = 17006]
90) Hall coefficient K and charge density
H
are related as
[Question ID = 4254]
1.
[Option ID = 17010]
2.

---

[Option ID = 17011]
3.
[Option ID = 17012]
4.
[Option ID = 17013]
Correct Answer :
[Option ID = 17012]
91) If E is energy level of electron and E is Fermi level, then
F
[Question ID = 4255]
1. all quantum states with E less than E will be empty at T= 0
F
[Option ID = 17014]
2. all quantum states with E higher than E will be occupied at T = 0
F
[Option ID = 17015]
3. all quantum states with E less than EF will be occupied at T = 0
[Option ID = 17016]
4. none of these
[Option ID = 17017]
Correct Answer :
all quantum states with E less than EF will be occupied at T = 0
[Option ID = 17016]
92) In a uniformly doped abrupt pn junction,the doping level of the n side is 4 times the doping level of p side.The ratio of
the depletion layer width is
[Question ID = 4256]
1. 0.2 [Option ID = 17018]
2. 0.25 [Option ID = 17019]
3. 0.5 [Option ID = 17020]
4. 1.0 [Option ID = 17021]
Correct Answer :
0.25 [Option ID = 17019]
93) A silicon bar is doped with donor impurities N = 2.25 x1015
3
D
/ cm . Given the intrinsic carrier concentration of silicon at
T = 300K is n = 1.5 x1010
3
i
/cm .Assuming complete impurity ionization,the equilibrium electron and hole concentrations are
[Question ID = 4257]
1. n =1.5 x 1016
3
5
0
/cm and p =1.5 ? 10
0
/cm [Option ID = 17022]
2. n =1.5 x 1010
15
3
0
/cm and P =1.5 x 10
0
/cm [Option ID = 17023]
3. n =2.25 x 1015
3
10
3
0
/cm and p = 1.5 x 10
0
/cm [Option ID = 17024]
4. n =2.25 x 1015
3
5
3
0
/cm and p =1 x 10
0
/cm [Option ID = 17025]
Correct Answer :
n =2.25 x 1015
3
5
3
0
/cm and p =1 x 10
0
/cm [Option ID = 17025]
94) Consider a Ge diode operating at 27 C and just beyond the threshold voltage of Ge, the value of dV/dT is
o
[Question ID = 4258]
1. 2.3 mV/ C
o
[Option ID = 17026]
2. 2.0 mV/ C
o
[Option ID = 17027]
3. 2.1 mV/ C
o
[Option ID = 17028]
4. 1.9 mV/ C
o
[Option ID = 17029]
Correct Answer :
2.3 mV/ C
o
[Option ID = 17026]
95) The reverse saturation current of a reverse biased PN junction diode increases 32 times due to rise in ambiant
temperature.If the original temperature was 40 C, What is the final temperature?
o
[Question ID = 4259]
1. 72o C [Option ID = 17030]
2. 45o C [Option ID = 17031]
3. 90o C [Option ID = 17032]
4. 50o C [Option ID = 17033]
Correct Answer :
90o C [Option ID = 17032]

---

96) A voltage V t = 2 sin t is applied across a capacitor having time varying capacitance given by Ct) = 1 + 0. 1sin t F. Then
current i(t) is
[Question ID = 4260]
1. 0.2 sin t cost + 2 cos t1 + 0.1sin t
[Option ID = 17034]
2. 0.1 sin t + 2 cos t
[Option ID = 17035]
3. 0.1 cos t + 2 sin t
[Option ID = 17036]
4. 0.2 sin t + 2 sin1 + 0.1sin t)
[Option ID = 17037]
Correct Answer :
0.2 sin t cost + 2 cos t1 + 0.1sin t
[Option ID = 17034]
97) In the circuit shown in figure,the power loss across the 5 resistor is
[Question ID = 4261]
1. 12 W [Option ID = 17038]
2. 51.2 W [Option ID = 17039]
3. 24 W [Option ID = 17040]
4. 34 W [Option ID = 17041]
Correct Answer :
51.2 W [Option ID = 17039]
98) In the circuit shown in the figure,the magnitude of current through the 5 resistor is
[Question ID = 4262]
1. 0.8 A [Option ID = 17042]
2. 1.5 A [Option ID = 17043]
3. 3.0 A [Option ID = 17044]
4. 2.3 A [Option ID = 17045]
Correct Answer :
1.5 A [Option ID = 17043]
99) What should be the value of R to have maximum power transfer in the circuit shown below
[Question ID = 4263]
1. 1.2 [Option ID = 17046]
2. 12 [Option ID = 17047]
3. 1.765 [Option ID = 17048]
4. 3.85 [Option ID = 17049]

---

Correct Answer :
1.765 [Option ID = 17048]
100) The driving point admittance of the network shown in figure is
[Question ID = 4264]
1.
[Option ID = 17050]
2.
[Option ID = 17051]
3.
[Option ID = 17052]
4.
[Option ID = 17053]
Correct Answer :
[Option ID = 17051]

---