ELECTRONICS AND COMMUNICATION PAGE 4
1. In any linear network, the elements like inductor, resistor and capacitor always_________ Remains constant irrespective of change in temperature, voltage and time
2. FORTRAN was developed by IBM
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. Programming language which is extension of BASIC s.... COMAL
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.In Pascal and COMAL programming language, symbol ' := ' is used for..... Reference
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. The first high level language to be implemented on personal computers FORTRAN
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. Video modulation for television is Vestigial sideband modulation
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. The sound and video signals are separated at the _____ of the TV receiver Video detector
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. A low-contrast picture in which white seems flat and lacking in detail suggest..... Low beam current
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
2. FORTRAN was developed by IBM
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. Programming language which is extension of BASIC s.... COMAL
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.In Pascal and COMAL programming language, symbol ' := ' is used for..... Reference
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. The first high level language to be implemented on personal computers FORTRAN
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. Video modulation for television is Vestigial sideband modulation
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. The sound and video signals are separated at the _____ of the TV receiver Video detector
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. A low-contrast picture in which white seems flat and lacking in detail suggest..... Low beam current
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