ELECTRONICS & COMMUNICATION ENGINEERING

1. In any linear network, the elements like inductor, resistor and capacitor always_________
Remains constant irrespective of change in temperature, voltage and time
2. A parallel RLC circuit has R=10,000Ωs; L=10mH; and c=1µF.The resonant frequency 𝜔o
(rad/sec) and Q are respectively given by....
104 and 100

3. For a coil with inductance L and resistance R in series with a capacitor C has...
Resonance impedance R.

4. Which law plays a significant role in the loop analysis of the network?
KVL

5. In Parallel Resonance of: R – L – C circuit having an R –L as series branch and ‘C’

forming parallel branch. which statement is correct
𝟏 𝟏 𝑹𝟐
𝒇𝒓 = √[ − ]
𝟐𝝅 𝑳𝑪 𝑳𝟐

6. Which type of networks allow the physical separability of the network elements (resistors,
inductors & capacitors) for analysis purpose?
Lumped Networks

7. A series resonant circuit is inductive at f = 1000 Hz. The circuit will be capacitive somewhere at..
f < 1000 Hz.

8. A network function is said to have simple pole or simple zero is...

The poles and zeroes are not repeated

9. A delta connection contains three impedances of 60 Ω each. The impedances of

the equivalent star connection will be
20Ω each.

10. Bridged T network can be used as:

Attenuator

11. To calculate Thevenin’s equivalent value in a circuit

All voltage sources are shorted while current sources are opened

12. The following constitutes a bilateral element

Resistor

13. In a loss free RLC circuit the transient current is:

Sinusoidal

14. The velocity factor of a transmission line....

is governed by the relative permittivity of the dielectric

15. To a highly inductive circuit, a small capacitance is added in series. The angle between voltage and
 current will....
decrease

16. A transmission line works as an...

LPF

17. The reflection coefficient of a transmission line with a short-circuited load is...
0

18. The wattmeter method is used to measure power in a three-phase load. The wattmeter readings are
400W and -35W. Calculate the total active power.
365W

19. Which among the following get/s cancelled under the resonance condition in a.c. circuits,
if inductive and capacitive reactances are in parallel?
Susceptance

20. The z-parameters of the shown T-network as shown in Fig.ure below are given by

13, 8, 8, 20

21. Input impedance of a short-circuited lossless line with length 𝜆/4is

Infinity

22. For a two port reciprocal network, the three transmission parameters are given by A = 4, B = 7 and C =
5. The value of D is equal to....
9

23. A pure resistance, 𝑅𝐿 when connected at the load end of a loss-less 100Ω line
produces a VSWR of 2. Then 𝑅𝐿 is....
50Ω and 200Ω

24. Millman’s theorem is applicable during determination of ...

Load current in a network with more than one voltage source

25. A voltage Standing Wave Ratio (VSWR) in terms of reflection coefficient 𝜌 is given by
(1+|ρ|)/(1-|ρ|)

26. An ideal filter should have.....

Zero attenuation in the pass band.

27. A constant K band-pass filter has pass-band from 1000 to 4000 Hz. The resonance frequency of
shunt and series arm is a..
2000 Hz
28. Double stub matching eliminates standing waves on the..
Source side of the left stub

29. Laplace transform of a unit Impulse function is..

1

30. A (3 + 4j) voltage source delivers a current of (4 + j5) A. The power delivered by the source is..
12W

31. In the m-derived HPF, the resonant frequency is to be chosen so that it is...
Below the cut-off frequency

32. Which theorem assists in replacement of an impedance branch over the network by the other
network comprising different circuit components, without affecting the V-I relations throughout
the entire network?
Substitution Theorem

33. What would be the nature of ‘ZL‘, if ‘Zeq‘ reactance is inductive according to ‘Maximum
power transfer theorem’?
Capacitive

34. What is the potential value of a reference or datum node used in the node analysis of a
network?
Zero

35. For an m-derived high pass filter, the cut off frequency is 4KHz and the filter has an
infinite attenuation at 3.6 KHz, the value of m is....
0.436

36. Which elements act as an independent variables in Y-parameters?

Voltage

37. What will be the nature of impedance at a frequency below the anti resonant frequency?
Inductive

38. In which of the diode the reverse recovery time nearly zero?
Schottky diode

39. In a degenerate n type semiconductor material, the Fermi level

is in conduction band

40. A change in frequency by a factor of 10 results in a _____ change in the ratio of the
normalized gain.
20-dB

41. Which of the following biasing techniques are affected by thermal runaway?
Fixed bias
42. For a BJT, under the saturation condition,
IC < βIB

43. If a sample of germanium and a sample of Si have the impurity density and are kept at
room temperature then
resistivity of Si will be higher than that of germanium

44. Thermal stability can be obtained by_________

heat sink

45. A transistor has hie =1KΩ and hfe=60 with an bypassed emitter resistor Re=1kΩ. What
will be the input resistance and output resistance?
63kΩ and 40kΩ respectively

46. The _____ in the Fourier series has the same frequency as the square wave itself.
Fundamental

47. Which one of the following is a passive element?

INDUCTOR

48. A _____ differential amplifier is particularly well suited for battery operation due to its
low power consumption.
CMOS

49. When a voltmeter is placed across a forward-biaseddiode, it will read a voltage

approximately equal to
The diode barrier potential

50. In a transmission line terminated by characteristic impedance, Zo

There is no reflection of the incident wave.

51.

For the connections shown below, the equivalent logic gate is

OR gate

52. The units frequently used to measure the forward bias and reverse bias current of a diode
are
mA and µA respectively

53. An n-type semiconductor material

has pentavalent impurity atoms added.
54. There is a small amount of current across the barrier of a reverse-biased diode. This
current is called
reverse leakage current.

55. A transistor amplifier has a voltage gain of 100. If the input voltage is 75 mV, the output
voltage is:
7.5V

56. What is the order of doping, from heavily to lightly doped, for each region?
emitter, collector, base

57. Current control device is...

BJT

58. What is the effect of MOSFET biasing in the saturation region especially while
representing the internal resistances and capacitances in n-channel E-MOSFET
configuration?
Channel gets pinched off at the drain by decreasing the value of Cgd upto zero

59. The phase difference between the input and output voltages in a common base
arrangement is …………….
0 degrees

60. When transistors are used in digital circuits they usually operate in the ………….
Saturation and cutoff region

61. When a silicon diode is forward biased, VBE for a CE configuration is ……..
0.7

62. Identify the nature of the field, if the divergence is zero and curl is also zero.
Solenoidal, irrotational

63. A circular disc of radius 5m with a surface charge density ρs = 10sinφ is enclosed by
surface. What is the net flux crossing the surface?
0

64. For free space propagation

γ = a + jβ

65. The main difference between the operation of transmission liners and waveguides is that
Transmission lines use the principal mode of propagation, and therefore do not
suffer from low-frequency cut-off

66. What is the distance between a voltage maximum and adjacent current maximum on a
transmission line with standing waves?
Wavelength/4

67. A flat transmission line delivers 5 kW at 10 A. What is its impedance?

50Ωs
68. Which among the following is also regarded as Twin-lead transmission line?
Open-wire

69. Which primary constant of transmission line is exhibits its dependency of value on the
cross-sectional area of conductors?
Resistance

70. Voltage shunt feedback amplifier forms

A negative feedback

71. If the input to a differentiating circuit is a saw-tooth wave, then output will be …………
Rectangular

72. For an integrating circuit to be more effective, the RC product should be......the time
period of the input wave
10 times greater than

73. Quantizing noise occurs in

PCM

74. What would happen, if the signal Xd passes through the feedback network?
Xd will get multiplied by 'β'

75. For a wide range of oscillations in the audio range the preferred oscillator is...
Wien bridge

76. The power dissipation, PD, of a logic gate is the product of the ________.
dc supply voltage and the average supply current

77. A 10MHz square wave clocks a 5bit ripple counter. The frequency of the 3rd flip-flop
output is
1.25MHz

78. In the design of logic circuits there is a trade-off between

Propagation delay and power dissipation

79. A memory of 8K means

8 x 1024

80. A counter displays a sequence of numbers .If a reading corresponds to the hexadecimal
number F52E, the next two readings are respectively...
F52F, F530

81. In a transmitter generally……………. oscillator is used

Crystal
82. A high Q tuned circuit will permit an amplifier to have high ……………
Selectivity

83. The expression for Exclusive OR is given by

̅̅̅̅̅̅̅
(𝑨𝑩) (A+B)

84. The sum S of A and B in a half adder can be implemented by using kNAND gates. The
value of k is
4

85. Two wires that are bent 90 degrees apart

Dipole

86. It is a linear array antenna consisting of a dipole and two or more parasitic elements: one
reflector and one director
yagi-uda antenna

87. The magnetic field of an antenna is perpendicular to the earth. The antenna’s polarization
is horizontal

88. Device to split transmission line current to two or more antenna towers
Phasor circuit

89. A parabolic dish antenna has a diameter of 3m and operates at 46 Hz. Calculate the
aperture.
4.59 square meters

90. _____ is the angle between the half-power radiation points

Beamwidth

91. A vertical loop antenna has a

A bidirectional radiation pattern in the horizontal plane

92. A waveguide assembly that lets the radar transmitter and receiver share an antenna is
called
Duplexer

93. Helical antennas are often used for satellite tracking at VHF because of
The Faraday effect

94. When the electric field in a waveguide is perpendicular to the direction of wave
propagation, the mode is said to be
Transverse electric

95. When is an echo box used on ships?

Testing only
 96. Increasing the diameter of a parabolic reflector causes which of the following:
Decreased beam width and increased gain

97. In waveguides, if no component of the E field is in the direction of propagation the mode
is said to be
TE

98. The most widely used microwave antenna is a

Horn

99. The multicavity klystron

Is not a good low-level amplifier because of noise

100. In electromagnetic waves, polarization

is due to the transverse nature of the waves

101. Microwave signals propagate by way of the

Direct wave

102. A special condition which occurs when the density of the lower atmosphere is such that
electromagnetic waves are trapped between it and earth’s surface
Duct propagation

103. As a ground-wave signal moves away from the transmitter, the ground wave eventually
disappears due to the
Tilting

104. A high-power microwave pulse of the order of megawatts can be generated by a

magnetron

105. A reflex klystron is oscillating at the frequency of its resonant cavity. If the reflector
voltage is made slightly less negative, the
The frequency will decrease

106. As the electron beam moves through a klystron’s intercavity drift space
Velocity modulation at the input cavity creates density modulation at the output
cavity

107. What ferrite device can be used instead of duplexer of isolate microwave transmitter and
receiver when both are connected to the same antenna?
Circulator

108. At frequencies below 1.5 MHz, what propagation provides the best coverage?
Ground wave

109. Which of the reception problems below that is not due to multipath?
Slow fading
110. Stripline and microstrip transmission lines are usually made with
PCBs

111. Which of the following permits a microwave signal to travel in one direction with
virtually no loss, but severely attenuates any signal attempting to travel in the reverse
direction?
Isolator

112. A duplexer circuit allows a transmitter and a receiver to operate from the same antenna
with virtually no interaction. This circuit may be replaced by a (an)
Circulator

113. Decreasing the volume of a cavity causes its resonant frequency to

Decrease

114. Low-power Gunn diodes are replacing

Reflex klystrons

115. Calculate the depth of modulation when a transmitter radiates a signal of 9.8KW
after modulation and 8KW without modulation of the signal.
67%

116. In TV transmission, picture signal is ……………… modulated

Amplitude

117. In a radio receiver, noise is generally developed at

RF stage

118. The type of modulation of the sound carrier signal is ______.

Frequency modulation

119. The function of ferrite antenna is to …………….

Increase the Q of tuned circuit

120. The IF is 455 kHz. If the radio receiver is tuned to 855 kHz, the local oscillator frequency
is ………….
1310 KHz

121. One of the following converts sound waves into AF signals

Microphone

122. It make use of the shape of IF filter frequency response roll-off versus frequency.
Slope detector

123. Super-heterodyne receiver has

Maximum stability, selectivity and sensibility
124. In the TV receivers, the device used for tuning the receiver to the incoming signal is..
Varactor diode

125. Interlacing is used in television to

Avoid flicker

126. In radar, very long wavelength.....

Requires very large reflectors

127. Pulse radar receiver if amplifier is designed as matched filter. If pulse width is 1µs ms
then bandwidth of if amplifier is...
1MHz

128. S-band radar frequency range is...

2-4 GHz

129. _________ detects the satellite signal relayed from the feed and converts it to an electric
current, amplifies and lower its frequency.
Satellite receiver

130. The COHO in MTI radar operates at the

Intermediate frequency

131. What kind of local oscillators does a radar receiver use?

Klystron

132. What is the advantage of LSA Diode over a Gunn Diode?

Higher power

133. What is the advantage of using Doppler radar?

shows only moving target

134. If a return echo arrives after the allocated pulse interval...

The target will appear closer than its actual distance

135. In radars, how is blooming prevented?

Limit the audio signal

136. A satellite beam that covers almost 42.4% of the earths surface.
Global beam

137. The smallest beam of a satellite antenna radiation pattern

Spot beam

138. What is the delay time for satellite transmission from earth transmitter to earth receiver?
0.5s
139. A satellite position is measured by its __________ angle with respect to the horizon.
Depression

140. A helical antenna is used for satellite tracking because of.....

Circular polarization

141. The television picture tube magnetic fields can be used for
Beam modulation

142. What is the maximum frequency deviation for audio modulation in TV transmission?
25 kHz

143. A low-contrast picture in which white seems flat and lacking in detail suggest.....
Low beam current

144. The sound and video signals are separated at the _____ of the TV receiver
Video detector

145. Video modulation for television is

Vestigial sideband modulation

146. The first high level language to be implemented on personal computers

FORTRAN

147. Which of the fallowing language was designed to solve the scientific and engineering
problems
PASCAL

148. In Pascal and COMAL programming language, symbol ' := ' is used for.....
Reference

149. Programming language which is extension of BASIC s....

COMAL

150. FORTRAN was developed by

IBM