QUESTION
SET -1 (ALL SUBJECT) 100 QUESTION
1. VSWR
on a transmission line is always
1. Equal to 1
2. Equal to 0
3. Less than 1
4. Greater than 1
2. In a amplitude modulated wave, the value of Vmax is 10V and Vmin is 5V. The %
modulation in this case is:
1. 2% b. 33.3% c. 50% d. 100%
3. The signal to noise ratio at the input of an amplifier can be improved:
1. By decrease the source impedance or resistance
2. By increasing the source impedance
3. By matching the source impedance with the input impedance of the amplifier
4. None of these
4. If the bandwidth of an amplifier is reduced, the thermal noise in the amplifier will:
1. Increase
2. Decrease
3. Not to be affected at all
4. Become random in nature
5. For the distortion to be minimum in a transmission line at audio frequencies, the
condition is
1. L = CR / G
2. L = GR / C
3. LG = R
4. LR = G
6. When electromagnetic waves are propagated in a waveguide
1. They travel along the broader walls of the waveguide
2. They travel through the dielectric without touching the wall
3. They are reflected from the walls but they do not travel along them
4. None of these
7. Communication between satellite and ground station is through
1. Tropospheric scatter
2. Ground wave
3. Sky wave
4. Line of sight propagation
8. A mast antenna is used mainly for
1. UHF
2. Short wave
3. Medium wave
4. VHF
9. A crystal which has a sensitivity of -55 dBm with 1 MHz BW amplifier will have a
sensitivity at 4 MHz BW amplifier equal to:
1. -55 dBm b. -58 dBm c. -52 dBm d. -60 dBm
10. Electromagnetic waves are refracted when they
1. Pass into a medium of different dielectric constant
2. Are polarized at right angles to the direction of propagation
3. Encounter a perfectly conducting surface
4. Pass through a small slot in a conducting medium
11. An aerial is fed from an amplitude modulation amplifier. Both the modulating
voltage and modulated voltage are sinusoidal. The aerial current (rms) before
modulation is 5 A and it increases to 5.8A after modulation. The percentage of
modulation index will be
1. 88% b. 80% c. 81.21% d. 83.14%
12. In a frequency demodulation, Foster-Seeley discriminator uses a
1. Single tuned circuit
2. Double tuned circuit in which both the primary and secondary are tuned to the
same frequency
3. Double tuned circuit in which both the primary and secondary are tuned to to
different frequencies
4. Combination of two transistors in push-pull operation
13. The wavelength of an electromagnetic wave in wave guide
1. Is directly proportional to the phase velocity
2. Is inversely proportional to the phase velocity
3. Is greater than that in free space
4. Depends only on the wave guide dimensions and the free space wavelength
14. The scale used for moving coil meter is
1. Non-linear scale
2. Linear scale
3. A square scale
4. A log scale
15. To double the circuit range of a 50 mA, 2000W meter movement, the shunt
resistance requires is
1. 40W b. 50W c. 2000W d. 25KW
16. A voltmeter utilizes a 20 mA meter movement. The sensitivity of the voltmeter is
1. 50 meg ohms per volt
2. 20 K ohms per volt
3. 50 kilo ohms per volt
4. 20 meg ohms per volt
17. A transformer, with a 20 : 1 voltage step-down ratio has 6V across 0.6 ohm in
the secondary, then Is and Ip given by
1. 10A, 5A
2. 5A, 10A
3. 10A, 0.5A
4. 1A, 0.5A
18. The temperature coefficient of resistance of a resistor is
1. Negative
2. Positive
3. Zero
4. Infinity
19. To prevent loading of the circuit under test, the input impedance of the
oscilloscope
1. Be low
2. Be high
3. Capacitive
4. Inductive
20. If the retrace is visible on the CRT display, then the trouble may be that
1. The fly back time of the time base saw tooth wave is not zero
2. The blanking control is not set properly
3. There is loss of SYNC signal
4. The intensity is too high
21. The lissajous pattern on CRO for two sinusoidal of frequency ratio 1 : 2 differing
in phase by 90 degrees, is
1. A straight line
2. A circle
3. An ellipse
4. An eight-shaped
22. When an electron starts from rest under the influence of electric and magnetic
fields perpendicular to each other, the path traversed by it will be
1. Ellipse
2. A parabola
3. Straight line
4. A cycloid
23. Frequency multipliers are usually
1. Class A amplifiers
2. Class B amplifiers
3. Class C amplifiers
4. Class AB amplifiers
24. The feedback network of a phase shift oscillator is usually consists of
1. RC circuit
2. RL circuit
3. LC circuit
4. C alone
25. Common base amplifier is most suitable for use in
1. Very high frequency circuits
2. Low frequency circuits
3. Medium frequency circuits
4. Low current circuits
26. If two amplifiers having identical bandwidth are cascaded, then the bandwidth of
the resulting amplifier will be
1. Less than that of each stage
2. Greater than that of each stage
3. Same as that of each stage
4. Double of each stage
27. Which one of the following amplifier has largest bandwidth
1. RC coupled amplifier
2. Difference amplifier
3. Transformer coupled amplifier
4. Direct coupled amplifier
28. In an amplifier, the emitter resistance by passed by a capacitor
1. Reduces the voltage gain
2. Increases the voltage gain
3. Causes thermal run away
4. None of these
29. The term free running is usually associated with
1. Bistable multivibrator
2. Astable multivibrator
3. Monostable multivibrator
4. None of these
30. The signal fed at the input of an ideal push-pull amplifier has frequency
components 150Hz’ 300Hz, 450Hz and 600Hz. The output signal will contain
1. Only 150 Hz frequency component
2. Only 150 Hz and 450 Hz frequency component
3. Only 300 Hz and 600 Hz frequency components
4. All the frequency components
31. For which of the following configuration [s] does the input resistance of the
amplifier depend strongly on the load resistance
1. CE b.CC c. CB d. CE and CB
32. An important advantage of the RC coupling scheme is
1. Economy
2. Excellent frequency reponse
3. High efficiency
4. Good impedance matching
33. The AC input to transistor oscillator is obtained from
1. The previous stage
2. A signal generator
3. DC power source
4. Its own internal circuit
34. The low frequency cut-off in an amplifier is due to
1. Only coupling capacitor
2. Only bypass capacitor
3. Both coupling and bypass capacitors
4. The internal transistor junction capacitances
35. In a half-wave rectifier the peak value of AC voltage across the secondary of the
transformer is 20/2 V. If no filter circuit is used, the maximum DC voltage across the
load will be
1. 28.28V b. 20V c. 14.14V d. None of these
36. Heat sinks ate used in a transistor working as power amplifier so as to
1. Increase the output power
2. Reduce the heat losses in toe transistors
3. Increase the voltage gain of the amplifier
4. Increase the collector dissipation rating of the transistors
37. In a power amplifier, the output power is proportional to
1. Vi b. Vi2 c. Vi3 d. Ö Vi
38. At half power frequencies the reduction in voltage gain of an amplifier equals
1. 6 dB b. 2 dB c. 3 dB d. 4 dB
39. the frequency of the ripple voltage at the output of a bridge rectifier operating
from a 50 Hz supply is
1. 25Hz b. 50 Hz c. 100 Hz d. 200 Hz
40. Darlington pair is used for
1. High current gain
2. High power gain
3. High frequency operation
4. Low distortion
41. The function of a bleeder resistor in a power supply is
1. Same as that of a load resistor
2. To ensure a minimum current drain in the circuit
3. To increase the output current
4. To increase the output DC voltage
42. A JFET has a potential divider bias arrangement. By mistake the resistor between
the gap and the power supply terminal is removed. The JFET will
1. Continue to work as an amplifier
2. Have a forward bias gate with respect to source
3. Not work as an amplifier but will work as a switch
4. Immediately burn out
43. The ripple factor of half-wave rectifier is
1. 0.482 b. 1.11 c. 1.21 d. 1.57
44. In the high frequency region of an RC coupled amplifier the circuit behave like a
1. Differentiator
2. A current amplifier
3. Low pass filter
4. High pass filter
45. Astable multivibrator can be used as
1. Squaring circuit
2. Comparator circuit
3. Voltage to frequency converter
4. Frequency of voltage converter
46. If the gain of the amplifier as A and the voltage feed back is fraction B of the
amplifier output voltage, the condition for maintenance of oscillation is
1. AB = 1 180o
2. AB = infinity
3. AB = 1 0o
4. AB < < 1
47. Nominal gain of an amplifier is 240. The noise level in the output without feed
back is 300 mV. If a feed back Beta = 1/ 60 used, the noise level in the output will
be
1. 1.66 mV b. 2.4mV c. 4mV d. 20mV
48. A zener diode is primarily used for
1. Rectification
2. Producing constant current
3. Producing constant voltage
4. Reverse bias
49. Cross over distortion is eliminated in a push-pull amplifier by
1. Using a transformer with a large step-up ratio
2. Using a transformer with a large step-down ratio
3. Providing a small forward bias to the transistors
4. Supplying both transistors with inphase signals
50. When a PNP transistor is saturated
1. Its base, emitter, and collector are all essentially at the same potential
2. Its emitter is at higher potential than the collector
3. Its collector is at higher potential than both base & emitter
4. None
51. For a RC high pass circuit
1. RC < < t
2. RC > > t
3. RC = t
4. None
52. An inverter is an equipment for transforming
1. AC to DC
2. AC to AC
3. DC to DC
4. DC to AC
53. Suppose you wish to amplify the potential difference between two points in a
circuit when neither of these points is grounded. Which one the following will you
prefer?
1. RC coupled amplifier
2. Transformer coupled amplifier
3. Difference amplifier
4. Direct coupled amplifier
54. In an emitter follower, the output voltage is
1. 180o out of phase from the input voltage
2. 90o out of phase from the input voltage
3. in phase with the input voltage
4. None
55. A silicon controlled rectifier can be considered to be:
1. Two pnp transistor connected back to back
2. Two npn transistor connected back to back
3. One npn and one pnp transistor connected back to back
4. Two zener diodes connected back to back
56. A rf signal contains three frequency components 870 KHz, 875 KHz 880 KHz.
This signal needs to be amplified. The amplifier used should be
1. Audio frequency amplifier
2. Wide band amplifier
3. Push pull amplifier
4. None
57. In the emitter follower circuit
1. The output current and voltage are inphase with the input current and voltage
respectively
2. The input and output impedances are equal
3. There is current series negative feedback
4. The output impedance is much higher than the input impedance
58. The frequency response of a system is the range of frequencies between the
upper and lower
1. 1 dB points
2. 6 dB points
3. 3 dB points
4. None
59. In a class C amplifier the output current is zero for
1. Half cycle
2. Full cycle
3. Less than half cycle
4. More than half cycle
60. When RL [load resistance] equals the internal resistance of a generator, which of
the following is maximum:
1. Power in RL
2. Current through RL
3. Voltage across RL
4. Efficiency of the circuit
61. negative feedback in an amplifier results in:
1. increased gain and increased bandwidth
2. increased gain and reduced bandwidth
3. reduced gain and increased bandwidth
4. reduced gain and reduced bandwidth
62. A class B push-pull amplifier suffers from
1. Cross-over distortion
2. Excessive harmonic distortion
3. Inter modulation distortion
4. None
63. An oscillator of the LC type that has split capacitor in the tank circuit is
1. Hartely oscillator
2. Wein bridge oscillator
3. Colpitts oscillator
4. None
64. Clamping circuits are also known as
1. AC restorer
2. DC restorer
3. Voltage to frequency converter
4. None
65. Which of the following has the greater mobility
1. Positive ion
2. Negative ion
3. Electrons
4. Holes
66. An N type semiconductor as a whole is
1. Positively charged
2. Electrically neutral
3. Negatively charged
4. None
67. In a semiconductor, the forbidden energy gap is of the order
1. 1 ev b. 6 ev c. 7 ev d. 0.1 ev
68. In LED, light is emitted because
1. Recombination of charges take place
2. We make the light fall on LED
3. Diode emits light when heated
4. None
69. UJT is also called
1. A voltage controlled device
2. A current controlled device
3. A relaxation oscillator
4. None
70. The transistor configuration which provides higher output impedance is
1. CC b. CB c. CE d. None
71. Tunnel diodes are fabricated from
1. Silicon
2. Germanium
3. Either silicon or germanium
4. Either germanium or gallium
72. N channel FETs are superior to P channel FETs because
1. They have a higher input impedance
2. They have a high switching time
3. They consume less power
4. Mobility of electrons is greater than that of holes
73. Diac is a solid state device which works as a
1. 2 terminal bidirectional switch
2. 2 terminal unilateral switch
3. 3 terminal bidirectional switch
4. None
74. Triac is a solid device which works as a
1. 2 terminal bidirectional switch
2. 3 terminal bidirectional switch
3. 4 terminal bidirectional switch
4. 2 terminal unilateral switch
75. Compared to a CB amplifier, a CE amplifier has
1. Lower input resistance
2. Higher output resistance
3. Lower current amplification
4. Higher current amplification
76. The input and output signals of a common emitter amplifier are:
1. Always equal
2. Out of phase
3. In phase
4. Always negative
77. The operation of a JEET involves
1. A flow of minority carriers
2. A flow of majority carriers
3. Recombination
4. Negative resistance
78. Solar cell is an example of a
1. Photo conductive device
2. Photo emissive device
3. Photo voltage device
4. None
79. Bretters and bolometers are used in the measurement of
1. Microwave power
2. VSWR
3. Transmission losses
4. None
80. A klystron operates on the principle of
1. Velocity modulation
2. Amplitude modulation
3. Pulse modulation
4. Frequency modulation
81. The unit of the amplification factor of a triode is
1. Decibels
2. Volt
3. Neper
4. None
82. A change in base current from 30 to 40 mA changes the collector current from
500 to 900 mA. The B factor for this power transistor equals
1. 900 b. 500 c. 3 d. 40
83. The field effect transistor can be used as
1. Variable capacitance
2. A constant voltage source
3. A variable resistance
4. A constant current source
84. Why NPN transistor are preferred over PNP transistor
1. NPN transistor have low heat dissipation
2. NPN transistor can handle large power
3. NPN transistor are cheap and easily available
4. None
85. The germanium transistors are seldom used above
1. 60oC b. 75oC c. 125oC d. 175oC
86. In a FET the drain voltage above which there is no increase in the drain current
is called
1. Pick off voltage
2. Critical voltage
3. Pinch off voltage
4. Break down voltage
87. A reflex klystron has
1. Only one cavity working both as the buncher & the catcher
2. Two cavities one for buncher and one for the catcher
3. Three cavities, two for buncher and one for catcher
4. No cavity at all
88. Bipolar junction transistors are seldom used as switching devices because
1. BJTs are not economical fro using as switching devices
2. They can handle only high voltage but not high currents
3. They need separate circuits when used as switching device
4. Of slow response and inability to withstand high voltage
89. The voltage at which the electron flow starts from the anode is called
1. Break down voltage
2. Peak inverse voltage
3. Peak voltage
4. Pinch off voltage
90. The heater filament of a vacuum tube is generally supplied with AC voltage (and
not DC voltage) for heating because
1. It results in a uniform heating of filament so that the electron emission also
uniform
2. It is very easy to obtain AC voltage from AC power mains
3. The DC voltage that would be required for heating has much greater magnitude
than the AC voltage
4. When DC is used for heating, a different type of filament is required which very
expensive
91. The dopant used for P type semiconductor is
1. Phosphorous
2. Boron
3. Carbon
4. Sodium
92. An example of negative resistance characteristic device
1. BJT b. MOSFET c. UJT d. PINdiode
93. The average DC voltage obtained from a bridge rectifier with a sine wave input V
sin wt is
1. V / 2 b. 2V c. 4V d. V
94. The maximum theoretical efficiency of a class B amplifier is
1. About 20%
2. About 50%
3. About 75%
4. 100%
95. A cascade amplifier is
1. A CE amplifier followed by CC amplifier
2. A CE amplifier followed by CB amplifier
3. A CC amplifier followed by CB amplifier
4. A CB amplifier followed by CE amplifier
96. Toggle switches can be debounced using
1. Astable multivibrator
2. Shift register
3. RS flip flop
4. None
97. A band pass filter has a centre frequency at 5 KHz. The 3 dB cut off frequencies
are 4.5 KHz and 5.5 KHz. The Q factor of the filter is
1. 5 b. 0.2 c. 5.2 d. 0.45
98. The domestic buzzer makes use of
1. Hall effect
2. Tunneling effect
3. Natural resonance
4. Piezoelectric effect
99. The device which uses avalanche breakdown is
1. PIN diode
2. Zener diode
3. Impart diode
4. GUNN diode
100. The correct relation between Alpha and Beta of a transistor is
1. a / b-1 b.b=a-1 c. b = a / 1-a d. a = b + 1/ b
Answer
1. d
2. b
3. a
4. b
5. a
6. b
7. d
8. c
9. c
10. a
11. d
12. c
13. c
14. b
15. c
16. c
17. c
18. a
19. b
20. d
21. d
22. d
23. c
24. a
25. a
26. b
27. d
28. d
29. b
30. d
31. b
32. a
33. d
34. c
35. d
36. d
37. b
38. a
39. c
40. a
41. b
42. c
43. c
44. c
45. c
46. c
47. d
48. c
49. c
50. a
51. a
52. d
53. c
54. c
55. c
56. d
57. c
58. c
59. c
60. a
61. c
62. a
63. c
64. b
65. c
66. b
67. a
68. a
69. a
70. b
71. d
72. d
73. a
74. b
75. d
76. b
77. b
78. c
79. a
80. a
81. d
82. d
83. c
84. d
85. b
86. c
87. a
88. d
89. b
90. b
91. b
92. c
93. d
94. b
95. b
96. c
97. a
98. d
99. c
100.c
1. Equal to 1
2. Equal to 0
3. Less than 1
4. Greater than 1
2. In a amplitude modulated wave, the value of Vmax is 10V and Vmin is 5V. The %
modulation in this case is:
1. 2% b. 33.3% c. 50% d. 100%
3. The signal to noise ratio at the input of an amplifier can be improved:
1. By decrease the source impedance or resistance
2. By increasing the source impedance
3. By matching the source impedance with the input impedance of the amplifier
4. None of these
4. If the bandwidth of an amplifier is reduced, the thermal noise in the amplifier will:
1. Increase
2. Decrease
3. Not to be affected at all
4. Become random in nature
5. For the distortion to be minimum in a transmission line at audio frequencies, the
condition is
1. L = CR / G
2. L = GR / C
3. LG = R
4. LR = G
6. When electromagnetic waves are propagated in a waveguide
1. They travel along the broader walls of the waveguide
2. They travel through the dielectric without touching the wall
3. They are reflected from the walls but they do not travel along them
4. None of these
7. Communication between satellite and ground station is through
1. Tropospheric scatter
2. Ground wave
3. Sky wave
4. Line of sight propagation
8. A mast antenna is used mainly for
1. UHF
2. Short wave
3. Medium wave
4. VHF
9. A crystal which has a sensitivity of -55 dBm with 1 MHz BW amplifier will have a
sensitivity at 4 MHz BW amplifier equal to:
1. -55 dBm b. -58 dBm c. -52 dBm d. -60 dBm
10. Electromagnetic waves are refracted when they
1. Pass into a medium of different dielectric constant
2. Are polarized at right angles to the direction of propagation
3. Encounter a perfectly conducting surface
4. Pass through a small slot in a conducting medium
11. An aerial is fed from an amplitude modulation amplifier. Both the modulating
voltage and modulated voltage are sinusoidal. The aerial current (rms) before
modulation is 5 A and it increases to 5.8A after modulation. The percentage of
modulation index will be
1. 88% b. 80% c. 81.21% d. 83.14%
12. In a frequency demodulation, Foster-Seeley discriminator uses a
1. Single tuned circuit
2. Double tuned circuit in which both the primary and secondary are tuned to the
same frequency
3. Double tuned circuit in which both the primary and secondary are tuned to to
different frequencies
4. Combination of two transistors in push-pull operation
13. The wavelength of an electromagnetic wave in wave guide
1. Is directly proportional to the phase velocity
2. Is inversely proportional to the phase velocity
3. Is greater than that in free space
4. Depends only on the wave guide dimensions and the free space wavelength
14. The scale used for moving coil meter is
1. Non-linear scale
2. Linear scale
3. A square scale
4. A log scale
15. To double the circuit range of a 50 mA, 2000W meter movement, the shunt
resistance requires is
1. 40W b. 50W c. 2000W d. 25KW
16. A voltmeter utilizes a 20 mA meter movement. The sensitivity of the voltmeter is
1. 50 meg ohms per volt
2. 20 K ohms per volt
3. 50 kilo ohms per volt
4. 20 meg ohms per volt
17. A transformer, with a 20 : 1 voltage step-down ratio has 6V across 0.6 ohm in
the secondary, then Is and Ip given by
1. 10A, 5A
2. 5A, 10A
3. 10A, 0.5A
4. 1A, 0.5A
18. The temperature coefficient of resistance of a resistor is
1. Negative
2. Positive
3. Zero
4. Infinity
19. To prevent loading of the circuit under test, the input impedance of the
oscilloscope
1. Be low
2. Be high
3. Capacitive
4. Inductive
20. If the retrace is visible on the CRT display, then the trouble may be that
1. The fly back time of the time base saw tooth wave is not zero
2. The blanking control is not set properly
3. There is loss of SYNC signal
4. The intensity is too high
21. The lissajous pattern on CRO for two sinusoidal of frequency ratio 1 : 2 differing
in phase by 90 degrees, is
1. A straight line
2. A circle
3. An ellipse
4. An eight-shaped
22. When an electron starts from rest under the influence of electric and magnetic
fields perpendicular to each other, the path traversed by it will be
1. Ellipse
2. A parabola
3. Straight line
4. A cycloid
23. Frequency multipliers are usually
1. Class A amplifiers
2. Class B amplifiers
3. Class C amplifiers
4. Class AB amplifiers
24. The feedback network of a phase shift oscillator is usually consists of
1. RC circuit
2. RL circuit
3. LC circuit
4. C alone
25. Common base amplifier is most suitable for use in
1. Very high frequency circuits
2. Low frequency circuits
3. Medium frequency circuits
4. Low current circuits
26. If two amplifiers having identical bandwidth are cascaded, then the bandwidth of
the resulting amplifier will be
1. Less than that of each stage
2. Greater than that of each stage
3. Same as that of each stage
4. Double of each stage
27. Which one of the following amplifier has largest bandwidth
1. RC coupled amplifier
2. Difference amplifier
3. Transformer coupled amplifier
4. Direct coupled amplifier
28. In an amplifier, the emitter resistance by passed by a capacitor
1. Reduces the voltage gain
2. Increases the voltage gain
3. Causes thermal run away
4. None of these
29. The term free running is usually associated with
1. Bistable multivibrator
2. Astable multivibrator
3. Monostable multivibrator
4. None of these
30. The signal fed at the input of an ideal push-pull amplifier has frequency
components 150Hz’ 300Hz, 450Hz and 600Hz. The output signal will contain
1. Only 150 Hz frequency component
2. Only 150 Hz and 450 Hz frequency component
3. Only 300 Hz and 600 Hz frequency components
4. All the frequency components
31. For which of the following configuration [s] does the input resistance of the
amplifier depend strongly on the load resistance
1. CE b.CC c. CB d. CE and CB
32. An important advantage of the RC coupling scheme is
1. Economy
2. Excellent frequency reponse
3. High efficiency
4. Good impedance matching
33. The AC input to transistor oscillator is obtained from
1. The previous stage
2. A signal generator
3. DC power source
4. Its own internal circuit
34. The low frequency cut-off in an amplifier is due to
1. Only coupling capacitor
2. Only bypass capacitor
3. Both coupling and bypass capacitors
4. The internal transistor junction capacitances
35. In a half-wave rectifier the peak value of AC voltage across the secondary of the
transformer is 20/2 V. If no filter circuit is used, the maximum DC voltage across the
load will be
1. 28.28V b. 20V c. 14.14V d. None of these
36. Heat sinks ate used in a transistor working as power amplifier so as to
1. Increase the output power
2. Reduce the heat losses in toe transistors
3. Increase the voltage gain of the amplifier
4. Increase the collector dissipation rating of the transistors
37. In a power amplifier, the output power is proportional to
1. Vi b. Vi2 c. Vi3 d. Ö Vi
38. At half power frequencies the reduction in voltage gain of an amplifier equals
1. 6 dB b. 2 dB c. 3 dB d. 4 dB
39. the frequency of the ripple voltage at the output of a bridge rectifier operating
from a 50 Hz supply is
1. 25Hz b. 50 Hz c. 100 Hz d. 200 Hz
40. Darlington pair is used for
1. High current gain
2. High power gain
3. High frequency operation
4. Low distortion
41. The function of a bleeder resistor in a power supply is
1. Same as that of a load resistor
2. To ensure a minimum current drain in the circuit
3. To increase the output current
4. To increase the output DC voltage
42. A JFET has a potential divider bias arrangement. By mistake the resistor between
the gap and the power supply terminal is removed. The JFET will
1. Continue to work as an amplifier
2. Have a forward bias gate with respect to source
3. Not work as an amplifier but will work as a switch
4. Immediately burn out
43. The ripple factor of half-wave rectifier is
1. 0.482 b. 1.11 c. 1.21 d. 1.57
44. In the high frequency region of an RC coupled amplifier the circuit behave like a
1. Differentiator
2. A current amplifier
3. Low pass filter
4. High pass filter
45. Astable multivibrator can be used as
1. Squaring circuit
2. Comparator circuit
3. Voltage to frequency converter
4. Frequency of voltage converter
46. If the gain of the amplifier as A and the voltage feed back is fraction B of the
amplifier output voltage, the condition for maintenance of oscillation is
1. AB = 1 180o
2. AB = infinity
3. AB = 1 0o
4. AB < < 1
47. Nominal gain of an amplifier is 240. The noise level in the output without feed
back is 300 mV. If a feed back Beta = 1/ 60 used, the noise level in the output will
be
1. 1.66 mV b. 2.4mV c. 4mV d. 20mV
48. A zener diode is primarily used for
1. Rectification
2. Producing constant current
3. Producing constant voltage
4. Reverse bias
49. Cross over distortion is eliminated in a push-pull amplifier by
1. Using a transformer with a large step-up ratio
2. Using a transformer with a large step-down ratio
3. Providing a small forward bias to the transistors
4. Supplying both transistors with inphase signals
50. When a PNP transistor is saturated
1. Its base, emitter, and collector are all essentially at the same potential
2. Its emitter is at higher potential than the collector
3. Its collector is at higher potential than both base & emitter
4. None
51. For a RC high pass circuit
1. RC < < t
2. RC > > t
3. RC = t
4. None
52. An inverter is an equipment for transforming
1. AC to DC
2. AC to AC
3. DC to DC
4. DC to AC
53. Suppose you wish to amplify the potential difference between two points in a
circuit when neither of these points is grounded. Which one the following will you
prefer?
1. RC coupled amplifier
2. Transformer coupled amplifier
3. Difference amplifier
4. Direct coupled amplifier
54. In an emitter follower, the output voltage is
1. 180o out of phase from the input voltage
2. 90o out of phase from the input voltage
3. in phase with the input voltage
4. None
55. A silicon controlled rectifier can be considered to be:
1. Two pnp transistor connected back to back
2. Two npn transistor connected back to back
3. One npn and one pnp transistor connected back to back
4. Two zener diodes connected back to back
56. A rf signal contains three frequency components 870 KHz, 875 KHz 880 KHz.
This signal needs to be amplified. The amplifier used should be
1. Audio frequency amplifier
2. Wide band amplifier
3. Push pull amplifier
4. None
57. In the emitter follower circuit
1. The output current and voltage are inphase with the input current and voltage
respectively
2. The input and output impedances are equal
3. There is current series negative feedback
4. The output impedance is much higher than the input impedance
58. The frequency response of a system is the range of frequencies between the
upper and lower
1. 1 dB points
2. 6 dB points
3. 3 dB points
4. None
59. In a class C amplifier the output current is zero for
1. Half cycle
2. Full cycle
3. Less than half cycle
4. More than half cycle
60. When RL [load resistance] equals the internal resistance of a generator, which of
the following is maximum:
1. Power in RL
2. Current through RL
3. Voltage across RL
4. Efficiency of the circuit
61. negative feedback in an amplifier results in:
1. increased gain and increased bandwidth
2. increased gain and reduced bandwidth
3. reduced gain and increased bandwidth
4. reduced gain and reduced bandwidth
62. A class B push-pull amplifier suffers from
1. Cross-over distortion
2. Excessive harmonic distortion
3. Inter modulation distortion
4. None
63. An oscillator of the LC type that has split capacitor in the tank circuit is
1. Hartely oscillator
2. Wein bridge oscillator
3. Colpitts oscillator
4. None
64. Clamping circuits are also known as
1. AC restorer
2. DC restorer
3. Voltage to frequency converter
4. None
65. Which of the following has the greater mobility
1. Positive ion
2. Negative ion
3. Electrons
4. Holes
66. An N type semiconductor as a whole is
1. Positively charged
2. Electrically neutral
3. Negatively charged
4. None
67. In a semiconductor, the forbidden energy gap is of the order
1. 1 ev b. 6 ev c. 7 ev d. 0.1 ev
68. In LED, light is emitted because
1. Recombination of charges take place
2. We make the light fall on LED
3. Diode emits light when heated
4. None
69. UJT is also called
1. A voltage controlled device
2. A current controlled device
3. A relaxation oscillator
4. None
70. The transistor configuration which provides higher output impedance is
1. CC b. CB c. CE d. None
71. Tunnel diodes are fabricated from
1. Silicon
2. Germanium
3. Either silicon or germanium
4. Either germanium or gallium
72. N channel FETs are superior to P channel FETs because
1. They have a higher input impedance
2. They have a high switching time
3. They consume less power
4. Mobility of electrons is greater than that of holes
73. Diac is a solid state device which works as a
1. 2 terminal bidirectional switch
2. 2 terminal unilateral switch
3. 3 terminal bidirectional switch
4. None
74. Triac is a solid device which works as a
1. 2 terminal bidirectional switch
2. 3 terminal bidirectional switch
3. 4 terminal bidirectional switch
4. 2 terminal unilateral switch
75. Compared to a CB amplifier, a CE amplifier has
1. Lower input resistance
2. Higher output resistance
3. Lower current amplification
4. Higher current amplification
76. The input and output signals of a common emitter amplifier are:
1. Always equal
2. Out of phase
3. In phase
4. Always negative
77. The operation of a JEET involves
1. A flow of minority carriers
2. A flow of majority carriers
3. Recombination
4. Negative resistance
78. Solar cell is an example of a
1. Photo conductive device
2. Photo emissive device
3. Photo voltage device
4. None
79. Bretters and bolometers are used in the measurement of
1. Microwave power
2. VSWR
3. Transmission losses
4. None
80. A klystron operates on the principle of
1. Velocity modulation
2. Amplitude modulation
3. Pulse modulation
4. Frequency modulation
81. The unit of the amplification factor of a triode is
1. Decibels
2. Volt
3. Neper
4. None
82. A change in base current from 30 to 40 mA changes the collector current from
500 to 900 mA. The B factor for this power transistor equals
1. 900 b. 500 c. 3 d. 40
83. The field effect transistor can be used as
1. Variable capacitance
2. A constant voltage source
3. A variable resistance
4. A constant current source
84. Why NPN transistor are preferred over PNP transistor
1. NPN transistor have low heat dissipation
2. NPN transistor can handle large power
3. NPN transistor are cheap and easily available
4. None
85. The germanium transistors are seldom used above
1. 60oC b. 75oC c. 125oC d. 175oC
86. In a FET the drain voltage above which there is no increase in the drain current
is called
1. Pick off voltage
2. Critical voltage
3. Pinch off voltage
4. Break down voltage
87. A reflex klystron has
1. Only one cavity working both as the buncher & the catcher
2. Two cavities one for buncher and one for the catcher
3. Three cavities, two for buncher and one for catcher
4. No cavity at all
88. Bipolar junction transistors are seldom used as switching devices because
1. BJTs are not economical fro using as switching devices
2. They can handle only high voltage but not high currents
3. They need separate circuits when used as switching device
4. Of slow response and inability to withstand high voltage
89. The voltage at which the electron flow starts from the anode is called
1. Break down voltage
2. Peak inverse voltage
3. Peak voltage
4. Pinch off voltage
90. The heater filament of a vacuum tube is generally supplied with AC voltage (and
not DC voltage) for heating because
1. It results in a uniform heating of filament so that the electron emission also
uniform
2. It is very easy to obtain AC voltage from AC power mains
3. The DC voltage that would be required for heating has much greater magnitude
than the AC voltage
4. When DC is used for heating, a different type of filament is required which very
expensive
91. The dopant used for P type semiconductor is
1. Phosphorous
2. Boron
3. Carbon
4. Sodium
92. An example of negative resistance characteristic device
1. BJT b. MOSFET c. UJT d. PINdiode
93. The average DC voltage obtained from a bridge rectifier with a sine wave input V
sin wt is
1. V / 2 b. 2V c. 4V d. V
94. The maximum theoretical efficiency of a class B amplifier is
1. About 20%
2. About 50%
3. About 75%
4. 100%
95. A cascade amplifier is
1. A CE amplifier followed by CC amplifier
2. A CE amplifier followed by CB amplifier
3. A CC amplifier followed by CB amplifier
4. A CB amplifier followed by CE amplifier
96. Toggle switches can be debounced using
1. Astable multivibrator
2. Shift register
3. RS flip flop
4. None
97. A band pass filter has a centre frequency at 5 KHz. The 3 dB cut off frequencies
are 4.5 KHz and 5.5 KHz. The Q factor of the filter is
1. 5 b. 0.2 c. 5.2 d. 0.45
98. The domestic buzzer makes use of
1. Hall effect
2. Tunneling effect
3. Natural resonance
4. Piezoelectric effect
99. The device which uses avalanche breakdown is
1. PIN diode
2. Zener diode
3. Impart diode
4. GUNN diode
100. The correct relation between Alpha and Beta of a transistor is
1. a / b-1 b.b=a-1 c. b = a / 1-a d. a = b + 1/ b
Answer
1. d
2. b
3. a
4. b
5. a
6. b
7. d
8. c
9. c
10. a
11. d
12. c
13. c
14. b
15. c
16. c
17. c
18. a
19. b
20. d
21. d
22. d
23. c
24. a
25. a
26. b
27. d
28. d
29. b
30. d
31. b
32. a
33. d
34. c
35. d
36. d
37. b
38. a
39. c
40. a
41. b
42. c
43. c
44. c
45. c
46. c
47. d
48. c
49. c
50. a
51. a
52. d
53. c
54. c
55. c
56. d
57. c
58. c
59. c
60. a
61. c
62. a
63. c
64. b
65. c
66. b
67. a
68. a
69. a
70. b
71. d
72. d
73. a
74. b
75. d
76. b
77. b
78. c
79. a
80. a
81. d
82. d
83. c
84. d
85. b
86. c
87. a
88. d
89. b
90. b
91. b
92. c
93. d
94. b
95. b
96. c
97. a
98. d
99. c
100.c
SET 2
1. One of the following statement which is true for relative dielectric constant is -
a) It is dimensionless
b) It is not equal to unity for vacuum
c) It’s value for all substances is less than one
d) None
Answer is :- It is dimensionless
2. Pure metals generally have-
a) high conductivity and low temperature coefficient
b) high conductivity and large temperature coefficient
c) low conductivity and zero temperature coefficient
d) low conductivity and high temperature coefficient
Answer is :- high conductivity and large temperature coefficient
3. For small size, high frequency coils, the most common core material is
a) Air
b) Ferrite
c) Powdered ion
d) Steel
Answer is :- Air
4. For an abrupt junction Varactor diode, the dependence of device capacitance (C) on
applied reverse bias (V) is given by-
a) C a V1/3
b) C a V-1/3
c) C a V1/2
d) C a V-1/2
Answer is :- C a V-1/3
5. A superconductor is a-
a) A material showing perfect conductivity and Meissner effect below a critical
temperature
b) A conductor having zero resistance
c) A perfect conductor with highest dimagnetic susceptibility
d) A perfect conductor which becomes resistive when the current density through it
exceeds a critical valueAnswer is :-A material showing perfect conductivity and Meissner effect below a critical
temperature
6. When a semiconductor based temperature transducer has a temperature coefficient of –
2500 mV/0C then this transducer is indeed a-
a) Thermistor
b) Forward biased pn junction diode
c) Reverse biased pn junction diode
d) FET
Answer is :- Forward biased pn junction diode
7. The location of lightning arrestor is -
a) Near the transformer
b) Near the circuit breaker
c) Away from the transformer
d) None
Answer is :- Near the transformer
8. Time constant of an RC circuit increases if the value of the resistance is -
a) Increased
b) Decreased
c) Neither a nor b
d) Both a and b
Answer is :- Increased
9. Intrinsic semiconductors are those which -
a) Are available locally
b) Are made of the semiconductor material in its purest from
c) Have more electrons than holes
d) Have zero energy gaps
Answer is :- Are made of the semiconductor material in its purest from
10. The primary control on drain current in a JFET is exerted by -
a) Channel resistance
b) Size of depletion regions
c) Voltage drop across channel
d) Gate reverse bias
Answer is :- Gate reverse bias
11. The electrical conductivity of metals which is expressed in ohm-1 m-1 is of the order
of -
a) 1010
b) 105
c) 10-4
d) 10-6
Answer is :- 105
12. When biased correctly, a zener diode –
a) acts as a fixed resistance
b) has a constant voltage across it
c) has a constant current passing through it
d) never overheats
Answer is :- has a constant voltage across it
13. The current amplification factor adc is given by –
a) IC/IE
b) IC/IB
c) IB/IC
d) IB/IC
Answer is :- IC/IE
14. Compared to bipolars, FETs have-
a) high input impedance
b) low input impedance
c) same input impedance
d) none
Answer is :- high input impedance
15. The source-drain channel of JFET is -
a) ohmic
b) bilateral
c) unilateral
d) both a and b
Answer is :- both a and b
16. diac is equivalent to a -
a) Pair of SCRs
b) Pair of four layer SCRs
c) Diode and two resistors
d) Triac width
Answer is :- Pair of four layer SCRs
17. When a sample of N type semiconductor has electron density of 6.25 ´ 1011 /cm3 at 300K and if the intrinsic concentration of carriers in this sample is 2.5 ´ 1013/cm3 then the hole density will be –
a) 106/cm3
b) 103/ cm3
c) 1010/ cm3
d) 1012/ cm3
Answer is :- 103/ cm3
18. The statement ‘In any network of linear impedances, the current flowing at any point is equal to the algebraic sum of the currents caused to flow at that point by each of the sources of emf taken separately with all other emf’s reduced to zero’ represents -
a) Kirchhoff’s law
b) Norton’s theorem
c) Thevenin’s theorem
d) Superposition theorem
Answer is :- Superposition theorem
19. One of the following modes which has the characteristics of attenuation becoming less as the frequency is increased and is attractive at icrowave frequencies of circular cylindrical wave guides is –
a) TE1 mode
b) TM01 mode
c) TE01 mode
d) Higher order mode
Answer is :- TE01 mode
20. A two-port network is symmetrical if –
a) z11z22 – z12z21 = 1
b) h11h22 – h12h21 = 1
c) AD – BC = 1
d) y11y22 – y12y21 = 1
Answer is :-AD – BC = 1
21. For transmission line load matching over a range of frequencies, it is best to use a-
a) balun
b) broad band directional coupler
c) double stub
d) single stub of adjustable position
Answer is :- double stub
22. The poles and zeros of a driving point function of a network are simple and interlace on the negative real axis with a pole closest to the origin. It can be realised -
a) by an LC network
b) as an RC driving point impedance
c) as an RC driving point admittance
d) only by an RLC network
Answer is:- only by an RLC network
23. Poles and zeros of a driving point function of a network are simple and interlace on the jw axis. The network consists of elements –
a) R and C
b) L and C
c) R and L
d) R, L and C
Answer is :- L and C
24. For a two port reciprocal network, the output open circuit voltage divided by the input current is equal to –
a) B
b) Z12
c) —
d) h12
Answer is :- Z12
25. In a short electric doublet the radiation properties are so that-
a) The induction field diminishes as the square root of the distance and is only appreciable in the vicinity of the conductor.
b) In the radiation, magnetic field is minimum when the current is maximum.
c) The radiation resistance of a short doublet antenna is extremely high.
d) Mean rate of power through a unit area of spherical sphere surrounding this doublet is
proportional to the square of the elemental length, other factors remaining constant.
Answer is :-Mean rate of power through a unit area of spherical sphere surrounding this doublet is proportional to the square of the elemental length, other factors remaining constant.
26. The frequency modulated (FM) radio frequency range is nearly -
a) 250 –300 MHz
b) 150 – 200 MHz
c) 90 – 105 MHz
d) 30-70 MHz
Answer is :-90 – 105 MHz
27. In an underground cable the distortion in the transmission of carrier frequency can be
eliminated by using -
a) Inductive loading
b) Resistive loading
c) Capacitive loading
d) Shielding
Answer is :- Inductive loading
28. The characteristic impedance of a transmission line with inductance 0.294 mH /m and capacitance 60 pF/m is -
a) 49 W
b) 60 W
c) 70 W
d) 140 W
Answer is :- 70 W
30. For a quarter wavelength ideal transmission line of characteristic impedance 50 ohms and load impedance 100 ohms, the input impedance will be –
a) 25W
b) 50Wc) 100W
d) 150W
Answer is :- 25W
31. The depth of penetration or skin depth for an electromagnetic field of frequency ‘f’ in
a conductor of resistivity r and permeability m is-
a) inversely proportional to r and f and directly proportional to m
b) directly proportional to r and inversely proportional to f and m
c) directly proportional to f and inversely proportional to r and m
d) inversely proportional to r and m and directly proportional to f
Answer is :- directly proportional to r and inversely proportional to f and m
32. When an antenna has a gain of 44dB then assuming that the main beam of the antenna is circular in cross-section the beam width will be -
a) 0.4456 0
b) 1.44560
c) 2.44560
d) 3.44560
Answer is :- 2.44560
33. Lens antennas used for microwaves are usually made of -
a) Polystyrene
b) Glass of low refractive index
c) Paraboloid surfaces
d) Dielectric media having large refractive index An,
34. One of the following types of instrument which is an electrometer is -
a) Electrodynamometer
b) PMMC
c) Electrostatic
d) Moving iron
Answer is :- Electrostatic
35. When an ac current of 5A and dc current of 5A flow simultaneously through a circuit
then which of the following statement is true ?
a) An ac ammeter will read less than 10A but more than 5A
b) An ac ammeter will read only 5A
c) A dc ammeter will read 10A
d) A dc ammeter will read zero
Answer is :- An ac ammeter will read less than 10A but more than 5A
36. When Q factor of a circuit is high, then -
a) power factor of the circuit is high
b) impedance of the circuit is high
c) bandwidth is larged) none of these
Answer is :- none of these
37. The resolution of a logic analyser is -
a) the maximum number of input channels
b) the minimum duration of the glitch it can capture
c) it’s internal clock period
d) the minimum amplitude of input signal it can display
Answer is :- the minimum amplitude of input signal it can display
38. A memoryless system is –
a) causal
b) not causal
c) nothing can be said
d) none
Answer is :- causal
39. An air capacitor is a –
a) time variant
b) active device
c) time invariant
d) time invariant and passive device
Answer is :-time invariant and passive device
40. Thermistors are made of -
a) pure metals
b) pure insulators
c) sintered mixtures of metallic oxides
d) pure semiconductor
Answer is :- sintered mixtures of metallic oxides
41. Pirani gauge is used to measure –
a) very low pressures
b) high pressures
c) pressures in the region of 1 atm
d) fluid flow
Answer is :- very low pressures
42. These circuits converts input power at one frequency to output power at a different
frequency through one stage conversion –
a) AC voltage controllers
b) Cyclo converters
c) Phase controlled rectifiers
d) Inverters
Answer is :-Cyclo converters
43. In a forward voltage Triggering thyristor changes from –
a) off state to on state
b) on state to off state
c) on state to on state
d) off state to off state
Answer is :- off state to on state
44. A thyristor, when triggered, will change from forward blocking state to conduction
state if its anode to cathode voltage is equal to -
a) peak repetitive off state forward voltage
b) peak working off state forward voltage
c) peak working off state reverse voltage
d) peak non-repetitive off state forward voltage
Answer is :- peak working off state forward voltage
45. Gate characteristic of a thyristor-
a) is a straight line passing through origin
b) is of the type Vg = a + bIg
c) is a curve between Vg and Ig
d) has a spread between two curves of Vg – Ig
Answer is :-has a spread between two curves of Vg – Ig
46. A four quadrant operation requires-
a) two full converters in series
b) two full converters connected back to back
c) two full converters connected in parallel
d) two semi converters connected back to back
Answer is :-two full converters connected back to back
47. If for a single phase half bridge inverter, the amplitude of output voltage is Vs and the output power is P, then their corresponding values for a single phase full bridge inverter are –
a) Vs, P
b) Vs/2, P
c) 2Vs, 2P
d) 2Vs, P
Answer is :- 2Vs, 2P
48. In an enhancement type MOSFET the output V-I characteristics has –
a) only an ohmic region
b) only a saturation region
c) only ohmic region at 10 W voltage value followed by a saturation region at higher voltages
d)an ohmic region at large voltage values preceded by a saturation region at lower voltages
Answer is :- only ohmic region at 10 W voltage value followed by a saturation region at higher voltages
49. The energy gap in a semiconductor -
a) increases with temperature
b) remains constant
c) slightly increase with temperature
d) decrease with temperature
Answer is :-decrease with temperature
50. In an electronic circuit matching means -
a) connecting a high impedance directly to low impedance
b) selection of components which are compatible
c) transferring maximum amount of signal between different kinds of circuits.
d) RC coupled stages
Answer is :-transferring maximum amount of signal between different kinds of circuits.
51. P channel FETs are less superior than N channel FETs because
a) They have higher input impedance
b) They have high switching time
c) They consume less power
d) Mobility of electrons is greater than that of holes
Answer is :- Mobility of electrons is greater than that of holes
52. Small increase in temperature in the CE connected transistor is the -
a) Increase in ICEO
b) Increase in ac current gain
c) Decrease in ac current gain
d) Increase in output resistance
Answer is :- Increase in ICEO
53. An amplifier has a band width of 20 KHz and a midband gain of 50 without feedback. If a negative feedback of 1% is applied then bandwidth with feedback is -
a) 13. 3 KHz
b) 30KHz
c) 10KHz
d) 40KHz
Answer is :- 30KHz
54. The output of a class B amplifier -
a) is distortion free
b) consists of positive half cycles only
c) is like the output of a full wave rectifier
d) comprises short duration current pulses
Answer is :- consists of positive half cycles only
55. An amplifier with negative feedback -
a) lowers its lower 3 dB frequency
b) raises its upper 3 dB frequency
c) increases its bandwidth
d) all of the above
Answer is :- all of the above
56. What changes would be necessary in block C if FM signals are to be received -
a) Block becomes redundant
b) A FM detector would be required
c) A high frequency signal generator
1d) An additional local oscillator will be needed
Answer is :- A FM detector would be required
57. The main disadvantage of Diode-Transistor logic (DTL) is its-
a) greater speed
b) slower speed
c) average speed
d) none of the above
Answer is :- slower speed
58. Time delay Dt in digital signals in an SIS O shift register is given by –
a) Dt = N ´ Fc
b) Dt = N ´ 1/Fc
c) Dt = 1/N ´ Fc
d) Dt = N ¸ 1/Fc
Answer is :- ?t = N ´ 1/Fc
59. The output Qn is 1 in a JK flip flop and it does not change when clock pulse is
applied) The possible combination of Jn and Kn can be –
(y denotes don’t care)
a) y and 0
b) y and 1
c) 0 and y
d) 1 and y
Answer is :- y and 0
60. Basic memory cell of dynamic RAM consists of –
a) a flip flop
b) a transistor acting as a capacitor
c) a transistor
d) a capacitance
Answer is :- a transistor acting as a capacitor
61. The 2’s complement of 10002 is –
a) 0111b) 0101
c) 1000
d) 0001
Answer is :-1000
62. Master slave flip-flop is made up of –
a) two flip flops connected in series
b) two flip flops connected in parallel
c) a debouncer circuit
d) a-D- latch
Answer is :-two flip flops connected in series
63. Number of nybbles making one byte is –
a) 2
b) 4
c) 8
d) 16
Answer is :- 2
64. The intrinsic impedance of free space-
a) is independent of frequency
b) decreases with increase of frequency
c) increases with increase of frequency
d) varies as square root of frequency
Answer is :-is independent of frequency
65. A system consists of 12 poles and 2 zeroes. Its high frequency asymptote in its
magnitude plot has a slope of -
a) –200 dB/decade
b) –240 dB/decade
c) –230 dB/decade
d) –320 dB/decade
Answer is :- –200 dB/decade
66. Considering the conditions-
1. High loop gain 2. Less ringing 3. Greater damping 4 Negative dB gain margin System stability requirements would include?
a) 1 and 3
b) 1, 2 and 3
c) 1 and 4
d) 2, 3 and 4
Answer is :-2, 3 and 4 swer is :- Polystyrene,
67. In the equatorial plane only Geosynchronous satellite are launched because it is the only plane which provides –
a) 24 hour orbit
b) stationary satellite
c) global communication
d) zero-gravity environs
Answer is :- stationary satellite
68. Radio Broadcasting is an example of –
a) space multiplexing
b) time multiplexing
c) frequency multiplexing
d) none of the above
Answer is :- frequency multiplexing
69. PAM signals can be demodulation by using a –
a) Low pass filters (LPE) alone
b) A Schmitt trigger followed by a LPF
c) A differentiator followed by a LPF
d) A clipper circuit by a LPF
Answer is:- A clipper circuit by a LPF
70. In an FDM receiver channels can be separated by using –
a) AND gates
b) Band pass
c) differentiation
d) Integration
Answer is :- AND gates
71. The most common modulation system used for telegraphy is-
a) frequency shift keying
b) two – tone modulation
c) pulse code modulation
d) single tone modulation
Answer is :- frequency shift keying
72. Use of varoctor diode in generation of modulated segial be-
a) FM generation only
b) 100AM generation only
c) PM generation only
d) both PM and AM generation
Answer is :- FM generation only
73. In colour picture tube shadow mask is used to-
a) reduce x-ray emission
b) ensure that each beam strikes only its own dotsc) increase screen brightness
d) provide degaussing for the screen
Answer is :- increase screen brightness
74. The circuit that separates composite video warefore from the sync pulses is-
a) the keyed AGC amplifar
b) a clipper
c) an integrator
d) a sawtooth current
Answer is :- a sawtooth current
75. Band width of microwaves is-
a) 1GHz -103 GHz
b) 1GHz –100 GHz
c) 1 GHz –10 GHz
d) 1 GHz – 106 GHz
Answer is :- 1GHz -103 GHz
76. In transverse Magnetic mode-
a) no electric line is in direction of propagation
b) no magnetic line is in direction of propagation
c) bath magnetic & electric lines are is direction of propagation
d) neither magnetic nor electric lines in direction of propagation
Answer is :- no magnetic line is in direction of propagation
77. Signal transmission in sky wave propagation is due to –
a) Reforction of wave
b) Reflection of wave
c) Pierus through Inosphere
d) None
Answer is :- Reforction of wave
78. According to Barkhausen Criterion Phase shift of signal should be –
a) 6000
b) 9000
c) 18000
d) 36000
Answer is :- 3600
79. The transmission does not have -
a) Partition noise
b) Flicker noise
c) resistance
d) Short noise
Answer is :- Partition noise
80. Varoctor diode has non linearity of -
a) capacitance
b) Inductance
c) Resistance
d) Is a linear device
Answer is :- capacitance
81. Noise figure is calculated as –
a) i/p signal to noise ratio X o/p signal to noise ratio
b) i/p S/N Ratio / O/P S/N Ratio
c) i/p S/N Ratio / O/P S/N Ratio X 100
d) i/p S/N Ratio + O/P S/N Ratio
Answer is :- i/p S/N Ratio / O/P S/N Ratio
82. You can determine quickly the effect of adding poles and zeros by –
a) Nicholas chart
b) Nyquist plot
c) Bode plot
d) Root locus.
Answer is :- Bode plot
83. The polar plot of G(S) = intercepts real axis at w = wo. Then, the real part and wo are given by-
a) –5, 1
b) –2.5, 1
c) –5,0-5
d) –5, 2
Answer is :- –5, 1
84. Laplace transform F (s) of a function f (E) is given by F(s)=10s(s+7)/(s+1)(s+8)(s+10) The initial and final values of F (t) will be respectively-
a) zero and 1
b) zero and 10
c) 10 and zero
d) 70 and 80
Answer is :-10 and zero
85. A satellite link uses different frequencies for receiving and transmitting in order to –
a) avoid interference from terrestrial microwave links
b) avoid interference between its powerful transmitted signals and weak in coming signal
c) minimize free-space losses
d) maximize antenna gain
Answer is :- avoid interference between its powerful transmitted signals and weak in coming signal
86. The first determining factor in selecting a satellite system is its-
a) EIRP
b) Antenna size
c) Coverage area
d) Antenna gain
Answer is :- Coverage area
87. Equalizing pulses in TV are sent during-
a) horizontal blanking
b) vertical blanking
c) the serrations
d) the horizontal retrace
Answer is :-vertical blanking
1. One of the following statement which is true for relative dielectric constant is -
a) It is dimensionless
b) It is not equal to unity for vacuum
c) It’s value for all substances is less than one
d) None
Answer is :- It is dimensionless
2. Pure metals generally have-
a) high conductivity and low temperature coefficient
b) high conductivity and large temperature coefficient
c) low conductivity and zero temperature coefficient
d) low conductivity and high temperature coefficient
Answer is :- high conductivity and large temperature coefficient
3. For small size, high frequency coils, the most common core material is
a) Air
b) Ferrite
c) Powdered ion
d) Steel
Answer is :- Air
4. For an abrupt junction Varactor diode, the dependence of device capacitance (C) on
applied reverse bias (V) is given by-
a) C a V1/3
b) C a V-1/3
c) C a V1/2
d) C a V-1/2
Answer is :- C a V-1/3
5. A superconductor is a-
a) A material showing perfect conductivity and Meissner effect below a critical
temperature
b) A conductor having zero resistance
c) A perfect conductor with highest dimagnetic susceptibility
d) A perfect conductor which becomes resistive when the current density through it
exceeds a critical valueAnswer is :-A material showing perfect conductivity and Meissner effect below a critical
temperature
6. When a semiconductor based temperature transducer has a temperature coefficient of –
2500 mV/0C then this transducer is indeed a-
a) Thermistor
b) Forward biased pn junction diode
c) Reverse biased pn junction diode
d) FET
Answer is :- Forward biased pn junction diode
7. The location of lightning arrestor is -
a) Near the transformer
b) Near the circuit breaker
c) Away from the transformer
d) None
Answer is :- Near the transformer
8. Time constant of an RC circuit increases if the value of the resistance is -
a) Increased
b) Decreased
c) Neither a nor b
d) Both a and b
Answer is :- Increased
9. Intrinsic semiconductors are those which -
a) Are available locally
b) Are made of the semiconductor material in its purest from
c) Have more electrons than holes
d) Have zero energy gaps
Answer is :- Are made of the semiconductor material in its purest from
10. The primary control on drain current in a JFET is exerted by -
a) Channel resistance
b) Size of depletion regions
c) Voltage drop across channel
d) Gate reverse bias
Answer is :- Gate reverse bias
11. The electrical conductivity of metals which is expressed in ohm-1 m-1 is of the order
of -
a) 1010
b) 105
c) 10-4
d) 10-6
Answer is :- 105
12. When biased correctly, a zener diode –
a) acts as a fixed resistance
b) has a constant voltage across it
c) has a constant current passing through it
d) never overheats
Answer is :- has a constant voltage across it
13. The current amplification factor adc is given by –
a) IC/IE
b) IC/IB
c) IB/IC
d) IB/IC
Answer is :- IC/IE
14. Compared to bipolars, FETs have-
a) high input impedance
b) low input impedance
c) same input impedance
d) none
Answer is :- high input impedance
15. The source-drain channel of JFET is -
a) ohmic
b) bilateral
c) unilateral
d) both a and b
Answer is :- both a and b
16. diac is equivalent to a -
a) Pair of SCRs
b) Pair of four layer SCRs
c) Diode and two resistors
d) Triac width
Answer is :- Pair of four layer SCRs
17. When a sample of N type semiconductor has electron density of 6.25 ´ 1011 /cm3 at 300K and if the intrinsic concentration of carriers in this sample is 2.5 ´ 1013/cm3 then the hole density will be –
a) 106/cm3
b) 103/ cm3
c) 1010/ cm3
d) 1012/ cm3
Answer is :- 103/ cm3
18. The statement ‘In any network of linear impedances, the current flowing at any point is equal to the algebraic sum of the currents caused to flow at that point by each of the sources of emf taken separately with all other emf’s reduced to zero’ represents -
a) Kirchhoff’s law
b) Norton’s theorem
c) Thevenin’s theorem
d) Superposition theorem
Answer is :- Superposition theorem
19. One of the following modes which has the characteristics of attenuation becoming less as the frequency is increased and is attractive at icrowave frequencies of circular cylindrical wave guides is –
a) TE1 mode
b) TM01 mode
c) TE01 mode
d) Higher order mode
Answer is :- TE01 mode
20. A two-port network is symmetrical if –
a) z11z22 – z12z21 = 1
b) h11h22 – h12h21 = 1
c) AD – BC = 1
d) y11y22 – y12y21 = 1
Answer is :-AD – BC = 1
21. For transmission line load matching over a range of frequencies, it is best to use a-
a) balun
b) broad band directional coupler
c) double stub
d) single stub of adjustable position
Answer is :- double stub
22. The poles and zeros of a driving point function of a network are simple and interlace on the negative real axis with a pole closest to the origin. It can be realised -
a) by an LC network
b) as an RC driving point impedance
c) as an RC driving point admittance
d) only by an RLC network
Answer is:- only by an RLC network
23. Poles and zeros of a driving point function of a network are simple and interlace on the jw axis. The network consists of elements –
a) R and C
b) L and C
c) R and L
d) R, L and C
Answer is :- L and C
24. For a two port reciprocal network, the output open circuit voltage divided by the input current is equal to –
a) B
b) Z12
c) —
d) h12
Answer is :- Z12
25. In a short electric doublet the radiation properties are so that-
a) The induction field diminishes as the square root of the distance and is only appreciable in the vicinity of the conductor.
b) In the radiation, magnetic field is minimum when the current is maximum.
c) The radiation resistance of a short doublet antenna is extremely high.
d) Mean rate of power through a unit area of spherical sphere surrounding this doublet is
proportional to the square of the elemental length, other factors remaining constant.
Answer is :-Mean rate of power through a unit area of spherical sphere surrounding this doublet is proportional to the square of the elemental length, other factors remaining constant.
26. The frequency modulated (FM) radio frequency range is nearly -
a) 250 –300 MHz
b) 150 – 200 MHz
c) 90 – 105 MHz
d) 30-70 MHz
Answer is :-90 – 105 MHz
27. In an underground cable the distortion in the transmission of carrier frequency can be
eliminated by using -
a) Inductive loading
b) Resistive loading
c) Capacitive loading
d) Shielding
Answer is :- Inductive loading
28. The characteristic impedance of a transmission line with inductance 0.294 mH /m and capacitance 60 pF/m is -
a) 49 W
b) 60 W
c) 70 W
d) 140 W
Answer is :- 70 W
30. For a quarter wavelength ideal transmission line of characteristic impedance 50 ohms and load impedance 100 ohms, the input impedance will be –
a) 25W
b) 50Wc) 100W
d) 150W
Answer is :- 25W
31. The depth of penetration or skin depth for an electromagnetic field of frequency ‘f’ in
a conductor of resistivity r and permeability m is-
a) inversely proportional to r and f and directly proportional to m
b) directly proportional to r and inversely proportional to f and m
c) directly proportional to f and inversely proportional to r and m
d) inversely proportional to r and m and directly proportional to f
Answer is :- directly proportional to r and inversely proportional to f and m
32. When an antenna has a gain of 44dB then assuming that the main beam of the antenna is circular in cross-section the beam width will be -
a) 0.4456 0
b) 1.44560
c) 2.44560
d) 3.44560
Answer is :- 2.44560
33. Lens antennas used for microwaves are usually made of -
a) Polystyrene
b) Glass of low refractive index
c) Paraboloid surfaces
d) Dielectric media having large refractive index An,
34. One of the following types of instrument which is an electrometer is -
a) Electrodynamometer
b) PMMC
c) Electrostatic
d) Moving iron
Answer is :- Electrostatic
35. When an ac current of 5A and dc current of 5A flow simultaneously through a circuit
then which of the following statement is true ?
a) An ac ammeter will read less than 10A but more than 5A
b) An ac ammeter will read only 5A
c) A dc ammeter will read 10A
d) A dc ammeter will read zero
Answer is :- An ac ammeter will read less than 10A but more than 5A
36. When Q factor of a circuit is high, then -
a) power factor of the circuit is high
b) impedance of the circuit is high
c) bandwidth is larged) none of these
Answer is :- none of these
37. The resolution of a logic analyser is -
a) the maximum number of input channels
b) the minimum duration of the glitch it can capture
c) it’s internal clock period
d) the minimum amplitude of input signal it can display
Answer is :- the minimum amplitude of input signal it can display
38. A memoryless system is –
a) causal
b) not causal
c) nothing can be said
d) none
Answer is :- causal
39. An air capacitor is a –
a) time variant
b) active device
c) time invariant
d) time invariant and passive device
Answer is :-time invariant and passive device
40. Thermistors are made of -
a) pure metals
b) pure insulators
c) sintered mixtures of metallic oxides
d) pure semiconductor
Answer is :- sintered mixtures of metallic oxides
41. Pirani gauge is used to measure –
a) very low pressures
b) high pressures
c) pressures in the region of 1 atm
d) fluid flow
Answer is :- very low pressures
42. These circuits converts input power at one frequency to output power at a different
frequency through one stage conversion –
a) AC voltage controllers
b) Cyclo converters
c) Phase controlled rectifiers
d) Inverters
Answer is :-Cyclo converters
43. In a forward voltage Triggering thyristor changes from –
a) off state to on state
b) on state to off state
c) on state to on state
d) off state to off state
Answer is :- off state to on state
44. A thyristor, when triggered, will change from forward blocking state to conduction
state if its anode to cathode voltage is equal to -
a) peak repetitive off state forward voltage
b) peak working off state forward voltage
c) peak working off state reverse voltage
d) peak non-repetitive off state forward voltage
Answer is :- peak working off state forward voltage
45. Gate characteristic of a thyristor-
a) is a straight line passing through origin
b) is of the type Vg = a + bIg
c) is a curve between Vg and Ig
d) has a spread between two curves of Vg – Ig
Answer is :-has a spread between two curves of Vg – Ig
46. A four quadrant operation requires-
a) two full converters in series
b) two full converters connected back to back
c) two full converters connected in parallel
d) two semi converters connected back to back
Answer is :-two full converters connected back to back
47. If for a single phase half bridge inverter, the amplitude of output voltage is Vs and the output power is P, then their corresponding values for a single phase full bridge inverter are –
a) Vs, P
b) Vs/2, P
c) 2Vs, 2P
d) 2Vs, P
Answer is :- 2Vs, 2P
48. In an enhancement type MOSFET the output V-I characteristics has –
a) only an ohmic region
b) only a saturation region
c) only ohmic region at 10 W voltage value followed by a saturation region at higher voltages
d)an ohmic region at large voltage values preceded by a saturation region at lower voltages
Answer is :- only ohmic region at 10 W voltage value followed by a saturation region at higher voltages
49. The energy gap in a semiconductor -
a) increases with temperature
b) remains constant
c) slightly increase with temperature
d) decrease with temperature
Answer is :-decrease with temperature
50. In an electronic circuit matching means -
a) connecting a high impedance directly to low impedance
b) selection of components which are compatible
c) transferring maximum amount of signal between different kinds of circuits.
d) RC coupled stages
Answer is :-transferring maximum amount of signal between different kinds of circuits.
51. P channel FETs are less superior than N channel FETs because
a) They have higher input impedance
b) They have high switching time
c) They consume less power
d) Mobility of electrons is greater than that of holes
Answer is :- Mobility of electrons is greater than that of holes
52. Small increase in temperature in the CE connected transistor is the -
a) Increase in ICEO
b) Increase in ac current gain
c) Decrease in ac current gain
d) Increase in output resistance
Answer is :- Increase in ICEO
53. An amplifier has a band width of 20 KHz and a midband gain of 50 without feedback. If a negative feedback of 1% is applied then bandwidth with feedback is -
a) 13. 3 KHz
b) 30KHz
c) 10KHz
d) 40KHz
Answer is :- 30KHz
54. The output of a class B amplifier -
a) is distortion free
b) consists of positive half cycles only
c) is like the output of a full wave rectifier
d) comprises short duration current pulses
Answer is :- consists of positive half cycles only
55. An amplifier with negative feedback -
a) lowers its lower 3 dB frequency
b) raises its upper 3 dB frequency
c) increases its bandwidth
d) all of the above
Answer is :- all of the above
56. What changes would be necessary in block C if FM signals are to be received -
a) Block becomes redundant
b) A FM detector would be required
c) A high frequency signal generator
1d) An additional local oscillator will be needed
Answer is :- A FM detector would be required
57. The main disadvantage of Diode-Transistor logic (DTL) is its-
a) greater speed
b) slower speed
c) average speed
d) none of the above
Answer is :- slower speed
58. Time delay Dt in digital signals in an SIS O shift register is given by –
a) Dt = N ´ Fc
b) Dt = N ´ 1/Fc
c) Dt = 1/N ´ Fc
d) Dt = N ¸ 1/Fc
Answer is :- ?t = N ´ 1/Fc
59. The output Qn is 1 in a JK flip flop and it does not change when clock pulse is
applied) The possible combination of Jn and Kn can be –
(y denotes don’t care)
a) y and 0
b) y and 1
c) 0 and y
d) 1 and y
Answer is :- y and 0
60. Basic memory cell of dynamic RAM consists of –
a) a flip flop
b) a transistor acting as a capacitor
c) a transistor
d) a capacitance
Answer is :- a transistor acting as a capacitor
61. The 2’s complement of 10002 is –
a) 0111b) 0101
c) 1000
d) 0001
Answer is :-1000
62. Master slave flip-flop is made up of –
a) two flip flops connected in series
b) two flip flops connected in parallel
c) a debouncer circuit
d) a-D- latch
Answer is :-two flip flops connected in series
63. Number of nybbles making one byte is –
a) 2
b) 4
c) 8
d) 16
Answer is :- 2
64. The intrinsic impedance of free space-
a) is independent of frequency
b) decreases with increase of frequency
c) increases with increase of frequency
d) varies as square root of frequency
Answer is :-is independent of frequency
65. A system consists of 12 poles and 2 zeroes. Its high frequency asymptote in its
magnitude plot has a slope of -
a) –200 dB/decade
b) –240 dB/decade
c) –230 dB/decade
d) –320 dB/decade
Answer is :- –200 dB/decade
66. Considering the conditions-
1. High loop gain 2. Less ringing 3. Greater damping 4 Negative dB gain margin System stability requirements would include?
a) 1 and 3
b) 1, 2 and 3
c) 1 and 4
d) 2, 3 and 4
Answer is :-2, 3 and 4 swer is :- Polystyrene,
67. In the equatorial plane only Geosynchronous satellite are launched because it is the only plane which provides –
a) 24 hour orbit
b) stationary satellite
c) global communication
d) zero-gravity environs
Answer is :- stationary satellite
68. Radio Broadcasting is an example of –
a) space multiplexing
b) time multiplexing
c) frequency multiplexing
d) none of the above
Answer is :- frequency multiplexing
69. PAM signals can be demodulation by using a –
a) Low pass filters (LPE) alone
b) A Schmitt trigger followed by a LPF
c) A differentiator followed by a LPF
d) A clipper circuit by a LPF
Answer is:- A clipper circuit by a LPF
70. In an FDM receiver channels can be separated by using –
a) AND gates
b) Band pass
c) differentiation
d) Integration
Answer is :- AND gates
71. The most common modulation system used for telegraphy is-
a) frequency shift keying
b) two – tone modulation
c) pulse code modulation
d) single tone modulation
Answer is :- frequency shift keying
72. Use of varoctor diode in generation of modulated segial be-
a) FM generation only
b) 100AM generation only
c) PM generation only
d) both PM and AM generation
Answer is :- FM generation only
73. In colour picture tube shadow mask is used to-
a) reduce x-ray emission
b) ensure that each beam strikes only its own dotsc) increase screen brightness
d) provide degaussing for the screen
Answer is :- increase screen brightness
74. The circuit that separates composite video warefore from the sync pulses is-
a) the keyed AGC amplifar
b) a clipper
c) an integrator
d) a sawtooth current
Answer is :- a sawtooth current
75. Band width of microwaves is-
a) 1GHz -103 GHz
b) 1GHz –100 GHz
c) 1 GHz –10 GHz
d) 1 GHz – 106 GHz
Answer is :- 1GHz -103 GHz
76. In transverse Magnetic mode-
a) no electric line is in direction of propagation
b) no magnetic line is in direction of propagation
c) bath magnetic & electric lines are is direction of propagation
d) neither magnetic nor electric lines in direction of propagation
Answer is :- no magnetic line is in direction of propagation
77. Signal transmission in sky wave propagation is due to –
a) Reforction of wave
b) Reflection of wave
c) Pierus through Inosphere
d) None
Answer is :- Reforction of wave
78. According to Barkhausen Criterion Phase shift of signal should be –
a) 6000
b) 9000
c) 18000
d) 36000
Answer is :- 3600
79. The transmission does not have -
a) Partition noise
b) Flicker noise
c) resistance
d) Short noise
Answer is :- Partition noise
80. Varoctor diode has non linearity of -
a) capacitance
b) Inductance
c) Resistance
d) Is a linear device
Answer is :- capacitance
81. Noise figure is calculated as –
a) i/p signal to noise ratio X o/p signal to noise ratio
b) i/p S/N Ratio / O/P S/N Ratio
c) i/p S/N Ratio / O/P S/N Ratio X 100
d) i/p S/N Ratio + O/P S/N Ratio
Answer is :- i/p S/N Ratio / O/P S/N Ratio
82. You can determine quickly the effect of adding poles and zeros by –
a) Nicholas chart
b) Nyquist plot
c) Bode plot
d) Root locus.
Answer is :- Bode plot
83. The polar plot of G(S) = intercepts real axis at w = wo. Then, the real part and wo are given by-
a) –5, 1
b) –2.5, 1
c) –5,0-5
d) –5, 2
Answer is :- –5, 1
84. Laplace transform F (s) of a function f (E) is given by F(s)=10s(s+7)/(s+1)(s+8)(s+10) The initial and final values of F (t) will be respectively-
a) zero and 1
b) zero and 10
c) 10 and zero
d) 70 and 80
Answer is :-10 and zero
85. A satellite link uses different frequencies for receiving and transmitting in order to –
a) avoid interference from terrestrial microwave links
b) avoid interference between its powerful transmitted signals and weak in coming signal
c) minimize free-space losses
d) maximize antenna gain
Answer is :- avoid interference between its powerful transmitted signals and weak in coming signal
86. The first determining factor in selecting a satellite system is its-
a) EIRP
b) Antenna size
c) Coverage area
d) Antenna gain
Answer is :- Coverage area
87. Equalizing pulses in TV are sent during-
a) horizontal blanking
b) vertical blanking
c) the serrations
d) the horizontal retrace
Answer is :-vertical blanking
SET
3
1.
Resistivity of silicon in ohms cm. is approx. equal to
a. 50 b.
1012 c. 230k d. 10-6
2.
Rsistivity ofGermanium in ohms cm. is approx. equal to
a. 50 b.
10-12 c. 50k d. 10-6
3. The
number of free electrons/cubic cm intrinsic Germanium at room temperature
is
approx. equal to
a.
1.5*1010 b. 2.5*1013 c. 1000 d. 5*106
4. The
number of free electrons/cubic cm of intrinsic silicon at room temperature is
approx.
equal to
a.
1.5*1010 b. 2.5*1013 c. 10000 d. 5*106
5. The
forbidden energy gap for silicon is
a. 1.1eV
b. 067eV c. 0.97eV d. 1.7eV
6. The
forbidden energy gap for Germanium is
a. 1.1eV
b. 067eV c. 0.97eV d. 1.7eV
7. N type
material is formed by the addition of the following (penta valent )atom in n
to
semiconductor material
a.
Antimony
b.
Arsenic
c.
Phosphorous
d. Any of
the above
8. P type
material is formed by the addition of the following [Trivalent] atom tn to
semiconductor
material
a. Boron
b. Gallium c. Indium d. Any of the above
9.
Impurity atoms that produces N type material by its addition in semiconductor
is
called
a. Donar
b. Acceptor c. Conductor d. Insulator
10.
Impurity atoms that produces P type material by its addition in semiconductor
is
called
a. Donar
b. Acceptor c. Conductor d. Insulator
11.
Dynamic resistance of a diode Rd is if voltage changes is DVd and the current
change is
D Id
a. D Vd /
D Id
b. D Id /
D Vd
c. 1 /
DVd
d. 1 / D
Id
12. Point
contact diodes are preferred at very high frequency, because of its low
junction
a.
Capacitance and inductance
b.
Inductance
c.
Capacitance
13.
Identify the circuit given below
a. AND
gate
b. OR
gate
c.
Rectifier
d. NOR
gate
14.
Identify the circuit given below
a. AND
gate
b. OR
gate
c.
Rectifier
d. NOR
gate
15. DC
value of a Half wave rectifier with Em as the peak value of the input is
a.
0.318Em
b.
0.418Em
c.
0.518Em
d.
0.618Em
16.
Change in Zener voltage of 10V at 100o C if temperature co-efficient is 0.072%o
C as
a. 0.54 V
b. 0.74 V c. 0.64 V d. 0.14 V
17. If Tc
is th e% temperature co of / oC and Vz as zener voltage and T as change in
temperature
then the change in zener voltage is
c. 100.
Vz. Tc DT
d. None
of these of the above
18. PIV
for a full wave rectifier, if Em is the peak voltage is
a. Em b.
1.5Em c. 0.636Em d. 2Em
19.
Schottky Barrier diodes becomes important at
a. DC
level operation
b. Low
frequency operation
c. High
frequency operation
d. None
of these
20.
Clamping network is the one that will clamp the signal to a
a.
Different peak value
b.
Different DC level
c.
Different polarity level
d.
Different RMS level
21.
Clipping network is the one that will clip a portion of the
a. Input
signal without distorting the remaining portion
b. Input
signal with distorting the remaining portion
c. Any of
the above
d. None
of these
22.
Transition capacitance Ct of a Varicap diode with Knee voltage Vt, reverse
voltage
Vr and K, the constant based on semiconductor material and the construction
technique
& N dependent on type of junction is given by
a. 1 / K
(Vt + Vr)N/2
b. 1 / K
(Vt + Vr)N
c. K /
(Vt + Vr)N
d. K /
(Vt + Vr)1/N
23. Ct =
K / (Vt + Vr)N where Vt Knee voltage, Vr reverse voltage, K manufacturing
dependent
constant and N dependent on type of junction, for alloy junction the value
of N is
a. 1/3 b.
2/3 c. 1/2 d. 1/4
24. Ct =
K / (Vt + Vr)N where Vt Knee voltage, Vr reverse voltage, K manufacturing
dependent
constant and N dependent on type of junction, for diffused junction the
value of
N is
a. 1/3 b.
2/3 c. 1/2 d. 1/4
25. In
JFET, the drain current Id is given by (Idss drain – source saturation current
Vgs – Gate
– source voltage, Vp the pinch off voltage)
a. Idss[1
– Vp/Vgs]
b. Idss(1
– Vgs/Vp)2
c. Idss[1
– Vgs/Vp)
d. Idss(1
– Vgs/Vp)3/2
26. The
shadow mask in colour tube is used to
a. Reduce
X-Ray emission
b. Ensure
each beam hits its own dots
c.
Increase screen brightness
d.
Provide degaussing for the screen
27.
Indicate which of the following signal is not transmitted in colour TV
a. Y b. Q
c. R d. I
28.
Another name for horizontal retrace in TV receiver is the
a.
Ringing b. Burst c. Damper d. Fly back
29.
Another name for the colour sync in the colour TV system
a.
Ringing b. Burst c. Damper d. Fly back
30. The
HV anode supply for a picture tube of a TV receiver is generated in the
a. Mains
transformer
b.
Vertical output stage
c.
Horizontal output stage
d.
Horizontal oscillator
31. The
output of vertical amplifier is
a. Direct
current
b.
Amplified vertical sync pulse
c. A saw
tooth voltage
d. A saw
tooth current
32. In a
transistor if Alpha = 0.98, current gain is equal to
a. 29 b.
59 c. 69 d. 49
33. The
active region in the common emitter configuration means
a. Both
collector and emitter junction is reverse biased
b. The
collector junction is forward biased and emitter junction
c. The
collector junction is reverse biased and emitter junction is forwared biased
d. Both
collector & emitter junction are forward biased
34. The
saturation region in the common emitter configuration means that
a. Both
collector & emitter junction are reverse biased
b. The
collector junction is forward biased and emitter junction
c. The
collector junction is reverse biased and emitter junction is forwared biased
d. Both
collector & emitter junction are forward biased
35. The %
of Red, Green & Blue in 100% White Y is given by
a. 30%,
59%, 11%
b. 50%,
30%, 11%
c. 30%,
11%, 50%
d. 33.3%,
33.5%, 38.3%
36.
Equalizing pulse width, if H is the Horizontal sync rate
a. 0.64 H
b. 0.07 H c. 0.04 H d. 0.16 H
37. In a
simple RC network the bandwidth is equal to
a. 1/2 p
RC
b. RC / 2
c. 2 C /
p R
d. 2 p /
RC
38. The
time constant of a RC network is given by
a. RC b.
C/R c. R/C d. None of these
39. First
zero crossing of pulse frequency spectrum occurs at if d is the pulse width,
T is the
pulse repetition rate
a. 1/d b.
d/T c. T/d d. T
40. The
distortion less output characteristic of a network means
a.
Constant amplitude and linear phase shift over frequency
b. Linear
phase shift and amplitude need not be constant
c. Any
amplitude and phase
d. None
of these
41.
Single sideband means suppressed
a.
Carrier
b.
Carrier and one side band
c. One
side band
d. None
of these
42. In an
amplitude modulated signal, lower side band frequency is equal to (if the
carrier
frequency is fc and modulation frequency is fm)
a. fm +
fc b. fc – fm c. fm r fc d. fc / fm
43.
Modulation index of the frequency modulation depends on
a.
Amplitude & frequency of the modulation signal
b.
Frequency and amplitude of carrier signal
c.
Carrier frequency
d. None
of these
44. The
BW of the narrow band FM if modulating frequency is fm
a. 3 r fm
b. 2 r fm c. 2.5 r fm d. 10 r fm
45.
Reactance tube modulator is known for
a. FM b.
AM c. PPM d. PAM
46.
Bandwidth and rise time product is
a. 0.35
b. 0.45 c. 0.30 d. 0.49
47.
Energy gap, Lg, for Germanium at room temp [300o K] is
a. 0.72eV
b. 1.1eV c. 1.53eV d. 0.2eV
48. Volt
equivalent of temperature VT, at 116o K is
a. 0.11V
b. 0.01V c. 1.16V d. 0.1V
49.
Reverse saturation current of a Ge.diode is in the range of
a. mA b.
uA c. nA d. pA
50.
Cut-in voltage V for silicon is approximately
a. 0.2V
b. 0.6V c. 0.9V d. 1.1V
51. Every
10o C rise in temp. the reverse saturation current
a.
Doubles
b. Halves
c.
Triples
d. No
change
52. Hall
effect with reference to Metal or Semiconductor carrying a current I is placed
in a
transverse magnetic field B, an electric field E is induced in
a.
Parallel to B
b.
Perpendicular to I
c.
Perpendicular to both B & I
d.
Perpendicular to B
53. 1 eV
(electron volt) is equal to:
a. 1.9 r
10-20 J
b. 1.6 r
10-19 J
c. 1.6 r
10-20 J
d. 1.16 r
10-19 J
54. Donar
impurity is having a valency of:
a. 2 b. 3
c. 4 d. 5
55.
Acceptor impurity is having a valency of
a. 2 b. 3
c. 4 d. 5
56.
Electron volt arises from the fact that if any electron falls through a
potential of 1
volt, its
kinetic energy will
a.
Decrease, & potential energy will increase
b.
Increase & potential energy decrease
c. Be
unaltered & potential energy decreases
d.
Increase & potential energy increase
57. Hole
is created in a semiconductor material if one of following impurities are
added
a.
Antimony
b.
Arsenic
c. Indium
d.
Phosphorus
58.
Excess electron is created by
a. Boran
b.
Gallium
c. Indium
d.
Arsenic
59. A
snubber circuit is used across the SCR to protect against
a. The
di/dt of the anode current
b. The
dv/dt turn on
c.
L.di/dt of load inductance
d. None
of these
60.
Germanium has the valency of
a. 2 b. 3
c. 4 d. 5
61.
Silicon has the valency of
a. 2 b. 3
c. 4 d. 5
62. Hole
acts as a free charge carrier of polarity
a.
Negative
b.
Positive
c.
Neutral
d. None
of these
63. Burst
signal in NTSC system is 8 cycles of the frequency of
a. Colour
sub carrier
b.
Picture carrier
c. Sound
carrier
d. None
of these
64.
Colour sub carrier reference burst is superimposed on the
a. Back
porch of the each horizontal sync pulse
b. Front
porch of the each horizontal sync pulse
c. Front
porch of the each vertical sync pulse
d. Back
porch of the each vertical sync pulse
65. The
law of mass action with reference to semiconductor technology states that
the
product of free negative & positive concentration is a constant and
a.
Independent of amount of donor and acceptor doping
b.
Dependent on amount of donor and independent of the amount acceptor impurity
doping
c. Depend
on amount of both donor & acceptor impurity doping
d. None
of these
66. The
snubber circuit used across SCR is a simple
a. R-L
network
b. RLC
network
c. LC
network
d. RC
network
67. To
limit the rate of rise of SCR anode current a small
a.
Inductor is inserted in cathode circuit
b.
Inductor is inserted in anode circuit
c.
Capacitor is inserted in anode circuit
d.
Capacitor is inserted in cathode circuit
68.
Torque developed by a DC servo motor is proportional to the
a.
Product of power and time
b.
Product of armature current and back emf
c.
Armature voltage and armature current
d. Field
voltage and field current
69.
Proportional Integral control
a.
Reduces steady state error but reduces the forward gain
b.
Increases the forward gain and reduces the steady state error
c.
Increases the steady state error and increases the forward gain.
d. None
of these
70.
Increasing the servo bandwidth:
a.
Improves signal to noise ratio
b.
Improves speed response and lowers signal to noise ratio
c.
Improves power output
d. None
of these
71. Notch
filter is
a. Low
pass filter
b. High
pass filter
c. Narrow
stop band filter
d. Narrow
pass band filter
72. In TV
Receivers the Electron beam deflection method used is
a.
Electro static
b.
Electro magnetic
c.
Magnetic
d. All
the above
73. In a
line of sight communication the maximum range R in miles between the
receiver
antenna and transmitter antenna of height H in feet is approximately
a. R =
1.93 ÖH
b. R =
1.23 ÖH
c. R =
1.53 ÖH
d. R =
2.03 ÖH
74. In
wavelength of the 60 MHz carrier frequency is
a. 10
metres.
b. 15
metres
c. 5
metres
d. 2.5
metres
75. In
standard TV receiving antenna the dipole element is
a. 0.5 of
the wave length
b. 0.25
of the wave length
c. 1.5 of
the wave length
d. 1.0 of
the wave length
76. The
characteristics of FET are similar to:
a. Triode
b.
Tertode
c.
Pentode
d. Diode
77.
Charge coupled device is an array of capacitors whose structure is similar to:
a. Shift
register
b.
Flip-flop
c. NAND
gate
d.
Amplifier
78.
Operational amplifier characteristics are which of the following:
a.
Infinite gain
b.
Infinite input impedance
c. Output
impedance is zero
d. All of
the above.
79. The
typical value of the open loop gain in dB of an amplifier at DC with no
feedback
is:
a. 90 to
100
b. 80 to
90
c. 0 to
50
d. 50 to
70
80. The 3
dB band width means the frequency at which
a. The
open loop voltage gain reduced to 0.707
b. The
open loop gain reduced to unity
c.
Maximum voltage of a signal is without distortion
d. It is
a medium wave band width of radio receiver
81. Rise
time of an amplifier is defined as time required
a. To
change from 0 to 100 % of its final value
b. To
change from 0 to 50 % of its final value
c. To
change from 10 to 90 % of its final value
d. To
change from 10 to 100 % of its final value
82. High
speed amplifier design emphasized on
a.
Extremely small bandwidth
b. Very
slow response
c. Unity
gain bandwidth after 10 MHz
d. None
of these
83. Tuned
amplifier having the frequency range between
a. 150
KHz – 50 MHz
b. 100 Hz
– 100 KHz
c. 100
KHz – 120 KHz
d. 50 MHz
– 100 MHz
84. The
resonance frequency of a tuned circuit made up of R, L, C is given by
a. 1/2
pÖLC
b. 2 pÖLC
c. 2 p /
ÖLC
d. ÖLC /
2
85. The
voltage follower can be obtained using operational amplifier
a.
Without any feedback
b. Series
parallel feedback of unity
c.
Parallel feedback
d. Series
feedback
86.
Fidelity of the amplifier is when
a. It is
a linear amplifier
b. It
does not add or subtract any spectral components
c. It
amplifier each component by the same amount
d. All of
the above
87. What
would be the output when two input sine waves of frequency 50 KHz and
100 KHz
passed through an amplifier in the medium signal
a. 50 KHz
and 100 KHz
b. 100
KHz and 200 KHz
c. 50 KHz
and 150 KHz
d. All of
the above
88. The
important application of Schmitt trigger is
a. To
convert slowly varying input voltage to abrupt voltage change
b. To
convert abruptly varying input voltage into slowly varying output
c. To
change the frequency of the input
d. None
of these
89.
Meaning of decoding is
a. Binary
addition
b. Data
transmission
c.
Demultiplexing
d.
Storage of binary information
90.
Approximately how many number of gates are incorporated in SSL chip
a. 12
b. 100
c. Excess
of 100
d. Excess
of 1000
91. The
circuit diagram represents which one of the following
a. Half
adder
b. Full
adder
c. Exor
gate
d. AND
gate
92. Flip
flop cannot be called as
a.
Bistable multivibrator
b. 1 Bit
memory unit
c. latch
d. combinational
circuit.
93. The
important use of low pass filter in power supply is
a. To get
the regulation in the output voltage
b. To
filter out the ripple frequency
c. To
increase the current rating
d. To
convert AC into DC
94.
Binary equivalent of the decimal number 145 is
a.
10010001
b.
1001011
c.
1010001
d.
1100010
95. In
which of the following gate the output will be high when all the maintained at
high
level
a. NOR
b. AND
c. NAND
d. EXOR
96. Which
of the following definition is true in the De Morgan’s theorem
a.
Multiplication symbols are replaced by addition symbol
b.
Addition symbols are replaced by Multiplication symbol
c. Each
of the terms are expressed in the complementary form
d. All of
the above
97.
8421/BCD code fro a decimal number 149 is
a. 0001
0100 1001
b.
10010101
c.
10101001
d. None
of these
98.
Combinational circuit are mainly characterized by
a. Output
depends upon the previous state & presents state
b. Output
depends upon the input at that particular instant
c. Output
depends upon the presents state & the clock state
d. Output
does not depends upon the input at all
99. A
flip flop is defined as
a. A
bistable device with two complementary outputs
b. It is
memory element
c. It
will respond to input and it is a basic memory element
d. All of
the above
100. Four
bit code is called
a. Nibble
b. Byte
c. Word
d.
Register
ANSWERS
1. c
2. a
3. a
4. b
5. a
6. b
7. d
8. d
9. a
10. b
11. a
12. c
13. b
14. a
15. a
16. a
17. a
18. d
19. c
20. b
21. a
22. c
23. c
24. a
25. b
26. b
27. c
28. d
29. b
30. c
31. d
32. d
33. c
34. d
35. a
36. c
37. a
38. d
39. a
40. a
41. b
42. b
43. a
44. b
45. b
46. a
47. a
48. b
49. b
50. b
51. a
52. c
53. b
54. b
55. b
56. b
57. c
58. d
59. b
60. c
61. c
62. b
63. a
64. a
65. a
66. d
67. b
68. b
69. a
70. b
71. c
72. c
73. b
74. c
75. a
76. c
77. a
78. d
79. d
80. a
81. c
82. c
83. a
84. a
85. b
86. d
87. a
88. a
89. c
90. a
91. a
92. d
93. b
94. a
95. b
96. d
97. a
98. b
99. d
100.a
SET-4
1. Modern capacitors which have high capacitance in small size use a dielectric of
(A) paper (B) rubber (C) ceramic (D) Mylar
2. The Maximum spectral response of the germanium andsilicon is in the
(A) infrared region (B) ultraviolet region (C) visible region (D) x-ray region
3. For an insulating material, dielectric strength and dielectric loss should be respectively
(A) high and high (B) low and high (C) high and low (D) low and low.
4. In a distortion factor meter, the filter at the front end is used suppress
(A) odd harmonics (B) even harmonics (C) fundamental component (D) dc component
5. The coefficient of coupling between two air core coils depends on
(A) mutual inductance between two coils only (B) self inductances of the two coils only (C) mutual inductance and self inductances of the two coils (D) none
6. For a parallel plate capacitor which is being charged out of the following the incorrect statement is
(A) Energy stored in the capacitor does not enter it through the connecting wire through the space around the wires and plates of capacitor.
(B) Rate at which energy flows into this volume is equal to the integration of the poynting vector over the boundary of the volume between the plates.
(C) The poynting vector points everywhere radially outward of the volume between plates.
(D) The poynting vector points everywhere radially in to the volume between the plates.
7. The presence of alkali oxides in alumino silicate ceramics is likely to result in dielectric breakdown due to
(A) Polarization (B) Conductivity (C) Structural homogeneties (D) Ionization
8. Which of the following will serve as a donor impurity in silion
(A) Boron (B) Indium (C) Germanium (D) Antimony
9. Electrical contact materials used in switches, brushes and relays must possess
(A) high thermal conductivity and high melting point (B) Low thermal conductivity and low melting point
(C) High thermal conductivity and low melting point (D) Low thermal conductivity and high melting point.
10. An SCR can only be turned off via it's
(A) cathode (B) anode (C) gates (D) none
11.Gold is often diffused into silicon PN junction devices to
(A) increase the recombination rate (B) reduce the recombination rate
(C) make silicon a direct gap semiconductor (D) make silicon semi-metal
12 Withn nodes andb branches a network will have
(A) (b+n) links (B)b - n +1 links (C) b -n-1 links (D)b + n + 1 links
13. When a network has 10 nodes and 17 branches in all then the number of node pair voltages would be
(A) 7 (B) 9 (C) 10 (D) 45
14. In any atom the potential energy of an orbiting electron is
(A) always positive (B) always negative
(C) sometime positive, sometime negative (D) numerically less then its kinetic energy.
15. A delition MOSFET differs from a JFET in the sense that it has no
(A) channel (B) gate (C) P-N junctions (D) substrate
16. The advantage of a semiconductor strain gauge cover the wire round strain guage is that
(A) it is more sensitive (B) it is more linear (C) it is less temperature dependent
(D) it's cost is low
17. Barrier potential in a P-N junction is caused by
(A) thermally generated electrons and holes (B) diffusion of majority carriers across the junction
(C) migration of minority carriers across the junction (D) flow of drift current.
18. When an NPN transistor is properly biased then most of the electrons from the emitter
(A) recombine with holes in the base (B) recombine in the emitter itself
(C) pass through the base to the collector (D) are stopped by the junction barrier
19. The deplition voltage for silicon diode atµ0 bias is
(A) 0.5 volt (B) 0.3 volt (C) 0.7 volt (D) 1.1 volt
20. A UJT can
(A) be triggered by any one of it's three terminals (B) not be triggered
(C) be triggered by two of its three terminal only (D) be triggered by all of its terminals only.
21. The energy of electric field due to a spherical charge distribution of radiusr and inform charge density in vacuum is
22. Maxwells divergence equation for the magnetic field is given by
A. ▼* B = 0
B. ▼. B = 0
__ __
__ __
C. ▼* B = p
D. ▼. B = p
23. When a short grounded vertical antenna has a lengthL which is 0.05 1 at frequencyf and if it's radiation resistances atf isR Ohms, then its radiation resistance at a frequency2f will be
(A)R/2 ohms (B)R ohms (C)2R ohms (D)4R ohms
24.In a cylindrical cavity resonator, the two modes which are degenerate would include
(A)TE111 andTM111
(B)TE011 andTM011
(C)TE022 andTM111
(D)TE111 and TM011
25. When an antenna of input resistance 73 ohm is connected to a 50-ohm line and if the losses are ignored then its efficiency will be nearly
(A) 0.19 (B) 0.81 (C) 0.97 (D) 1.19
26.The transformer utilization factor of full wave bridge rectifier is
(A) 0.812 (B) 0.286 (C) 0.693 (D) 0.782
27. When a dominant mode wave guide not terminated in its characteristic impedance is excited with a 10 GHZ signal then ifd is the distance between two successive minima of the standing wave in the guide then
(A)d = 1.5 cm (B)d is less then 1.5 cm (C)d is greater then 1.5 cm (D)d = 3cm
28. A two port network having a 6 dB loss will give
(A) an output power which is one - quarter of the input power (B) an output power which is one - half of the input power
(C) an output voltage which is 0.707 of the input voltage. (D) an output power which is 0.707 of the input power.
29. While transporting a sensitive galvanometer
(A) the terminals are kept shorted (B) critical damping resistance is connected across the terminals
(C) the terminals are kept open circuited (D) it does not matter as to what is connected across the terminals.
30. A T type attenuator is designed for an attenuation of 40 dB and terminating resistance of 75 ohms.
Which of the following values represent full series armR1 and shunt armR2?
1.R1 = 147 Ω 2.R1 = 153 Ω 3.R1 = 1.5 Ω 4.R1= 3750 Ω
(A) 1 and 3 (B) 1 and 4 (C) 2 and 3 (D) 2 and 4
31. For a transmission line, the characteristic impedance with inductance 0.294µH/m and capacitance 60pF/m is
(A) 49Ω (B) 60Ω (C) 70Ω (D) 140Ω
32. When the graph of a network has six branches with three tree branches then the minimum number of equations required for the solution of the network is
(A) 2 (B) 3 (C) 4 (D) 5
33. Consider the following statement for a 2-port network
1.Z11 =Z22
2.h12 =h21
3.Y12 = -Y21
4.BC - AD = -1
then the network is reciprocal if and only if
(A) 1 and 2 are correct (B) 2 and 3 are correct (C) 3 and 4 are correct (D) 4 alone is correct.
34. As a network contains only independent current sources and resistors then if the values of all resistors are doubled then the values of the node voltages are
(A) will become half (B) will remain unchanged
(C) will become double (D) cannot be determined unless the circuit configuration and the values of the resistors are known.
35. A iron cored choke is a
(A) Linear and active device (B) Non linear and passive device (C) Active device only (D) Linear device only
36. Poynting vector wattmeter is based on
(A) Seebeck effect (B) Ferranti effect (C) Induction effect (D) Hall effect
37. Which one of the following is not a transducer in the true sense?
(A) Thermocouple (B) Piezoelectric pick-up (C) Photo voltaic cell (D) LCD.
38. The term used to denote a static device that converts ac to dc, de to ac, dc to dc or ac to ac is
(A) Converter system (B) Inverter (C) Chopper (D) Thyristor
39. When a dipole antenna of 1/8 length has an equivalent total resistance of 1.5 Watt then the efficiency of the antenna is
(A) 0.89159% (B) 8.9159% (C) 89.159% (D) 891.59%
40. In commercial FM broadcasting, the maximum frequency deviation is normally
(A) 5 KHz (B) 15 KHz (C) 75 KHz (D) 200 KHz
41. Weins bridge is used for measurement of frequency in the applied voltage waveform is measurement of frequency in the applied voltage waveform is
(A)sinusoidal (B) square (C) rectangular (D) triangular
42.Strain gauge is
(A) not a transducer (B) an active transducer (C) not an electronic instrument
43.A highQ coil has
(A) large band width (B) high losses (C) low losses (D) flat response
44. In the case of an instrument reading of 8.3 V with a 0 to 150 voltmeter having a guaranteed accuracy of 1% full scale reading, the percentage limiting error is
(A) 1.810% (B) 0.181% (C)12.45% (D) 0.0018%
45. The 'h' parameter equivalent circuit of a junction transistor is valid for
(A) High frequency, large signal operation (B) High frequency, small signal operation (C) Low frequency, large signal operation.
46. A system is causal if the output of any time depends only on
(A) Values of input in the past and in the future (B) Values of input at that time and in the past
(C) Values of input at that time and in the future (D) none
47. Form the hot metal surface electrons escape because
(A) of change of state from metal to gas due to heat. (B) of change of state from gas to metal (C) the energy supplied is greater than the work function (D) the energy is greater than Fermi level
48. The most common device used for detection in radio receivers is
(A) amplifier (B) triode (C) diode (D) transistor
49. In a full wave rectifier the negative point in a circuit is
(A) cathode (B) anode (C) The central tap on the high voltage secondary (D) plate.
50.Negative feedback amplifier has a signal corrupted by noise as its input. The amplifier will
(A) Amplify the noise as much as the signal (B) Reduce the noise (C) Increase the noise
(D) Not effect the noise
PART - II
51. It is an unidirectional device that blocks the current flow from cathode to anode
(A) SCR (B) PCR (C) VCR (D) DCR
52. An ideal constant current source is connected in series with an ideal constant voltage source. Considering together the combination will be a
(A) constant voltage source (B)constant current source
(C) constant voltage and a constant current source or a constant power source. (D) resistance
53. Anode current in an thyristor is made up of
(A) electrons only (B) electrons or holes (C) electrons and holes (D) holes only
54. For a pulse transformer, the material used for its core and the possible turn ration from primary to secondary are respectively
(A) ferrite : 20 : 1 (B) laminated iron : 1 :1 (C) ferrite : 1 : 1 (D) powered iron : 1: 1
55. A converter which can operate in both 3 pulse and 6 pulse mode is a
(A) 1 phase full converter (B) 3 phase half wave converter (C) 3 phase semiconverter (D) 3 phase full converter.
56. A single phase CSI has capacitor C as the load. For a constant source current, the voltage across the capacitor is
(A) square wave (B) triangular wave (C) step function (D) pulsed wave
57. a single phase full wave midpoint thyristor converter uses a 230/200V transformer with centre tap on the secondary side. The P.I.V per thyristor is
(A) 100V (B)141.4V (C)200V (D)282.8V
58. In dc choppers for chopping period T, the output voltage can be controlled by FM by varying
(A)T keepingTon constant (B)Ton keepingT constant
(C)Toff keepingT constant (D) None of the above
59.An ideal power supply consist of
(A) Very small output resistance (B) Zero Internal resistance
(C) Very large input resistance (D) Very large output resistance
60. The linearity error for a digital input is indicated by
(A) ξ (B) γ (C) η (D) ε
61. In the 8421 BCD code the decimal number 125 is written as
(A)1111101 (B) 0001 0010 0101 (C) 7D (D) None of the bove
62. Match the given feedback circuit with its proper nomenclatures
(A) Current series feedback (B) Current shunt feedback
(C) Voltage series feedback (D) Voltage shunt feedback
63. Class A amplifier is used when
(A) No phase inversion is required (B) Highest voltage gain is required
(C) dc voltages are to be amplified (D) Minimum distortion is desired.
64. Identity the correct match for the given transister
(A) Enhancement type P channel MOSFET (B) Depletion type N channel MOSFET
(C) Enhancement type N channel MOSFET (D) Depletion type P channel MOSFET
65. In case a signal band limited to fermimeter is sampled at a rate less than 2 fermimeter, the constructed signal will be
(A) Distortionless (B) Small in amplitude (C) Having higher frequencies suppressed (D) Distorted
66.IC which has quad 2 input AND gates
(A) 7411 (B) 7404 (C)7400 (D) 7408
67. Registers in which data is entered or taken out in serial form are referred as
(A) left shift register (B) right shift register (C) shift registers (D) none of the above
68. The expression ABC can be simplified to
__ __ __
A. A B C
B. AB+BC+CA
__
__ __ __
C. AB+ C
C. A + B + C
69. Read the following
(i) Routh Herwitz's criterion is in time domain
(ii)Root locus plot is in time domain
(iii) Bode plot is in frequency domain
(iv) Nyquist criterion is in frequency domain.
(A) 2,3 and 4 are correct (B) 1,2 and 3 are correct (C) 3 and 4 are correct (D) all four are correct
70. Register and counters are similar in the sense that they both
(A) count pulses (B) store binary operation (C) shift operation
(C) made from an array of flip flops and gates integrated on a single chip.
71. InD/A converter, the resolution required is 50mv and the total maximum input is 10v. The number of bits required is
(A) 7 (B) 8 (C) 9 (D) 200
72. On different unit impulse function results in
(A) Unit parabolic function (B) Unit triplet (C) Unit doublet (D) Unit ramp function
73. ........... watt of power is received from sun per m2 surface area of a geosynchronous satellite
(A) 100 (B) 500 (C) 2000 (D) 1000
74. The ripple factor in an LC filter.
(A) Increases with the load current (B) Increases with the load resistance
(C) Remains constant with the load current (D) Has the lowest value
75. In different parts of the country identical telephone numbers are distinguished by their
(A) Language digits (B) Access digits (C) Area codes (D) Central office codes
76.Amplitude modulation is used for broadcasting because
(A) it is move noise immune than other modulation systems
(B) compared with other systems it requires less transmitting power
(C) its use avoids receiver complexity
(D) no other modulation system can provide the necessary bandwidth for high fidelity.
77. The maximum phase shift that can be provided by a lead compensator with transfer function.
1+6S
G0(S) =______
1+2S
(A) 15o
(B) 45o
(C) 30o
(D) 60o
78. The correct sequence of steps required to improve system stability is
(A) Insertderivative action, use negative feedback, reduce gain (B) Reduce gain, use negative feedback, insert derivative action (C) Reduce gain, insert derivative action, use negative feedback (D) Use negative feedback, reduce gain, insert derivative action,
79. Identity slope change atω = 10 of the magnitudev/s frequency characteristic of a unity feedback system with the following open-loop transfer function.
A -80 dB/dec to -60 dB/dec
B 40 dB/dec to 20 dB/dec
C 20 dB/dec to -40 dB/dec
D 40 dB/dec to -20 dB/dec
80. In the feedback control system the loop transfer function is given by K
G(s)H(s)=_____________
S(s+2)(s2+2s+2) Number of asymptotes of its root loci is
A. 1 B. 2
C. 3
D. 4
81. In a closed - loop transfer function
G(s)
2600 k(s+25)
____= _____________________________
H(s)
s4+125s3+5100s2+65000s+65000 k
A. ±j228 B. ±j2.28 C. ±j1.14 D. j114
82. Considering the following statement : In a magic tee
1. the collinear arms are isolated from each other
2. one of the collinear is isolated from the E-arm
3. one of the collinear arm is isolated from the H-arm
4. E-arm and H-arm are isolated from each other. Of these statements
(A) 1 and 2 are correct (B) 1 and 3 are correct (C) 1 and 4 are correct (D) 2 and 3 are correct.
83. In 1965 first geostationary satellite was launched called
(A) ANIK (B) EARLY BIRD (Intel sat - 1) (C) WESTAR (D)MOLNIYA
84. When A = 0., B = 0, C = 1 then in two input logic gate we get gate
(A) XOR gate (B) AND gate (C) NAND gate (D) NOR gate
85. In a radio receiver the IF amplifier
(A) is tuned above the stations incoming frequency (B) amplifies the output of local oscillator
(C) is fixed tuned to one particular frequency (D) can be tuned to various isolate frequencies
86. A duplexer is used to
(A) Couple two antennas to a transmitter without interference
(B) isolate the antenna from the local oscillator
(C) prevent interference between two antennas connected to a receiver
(D) use an antenna for reception or transmission without interference.
87. Boolean algebra is based on
(A) numbers (B) logic (C) truth (D) symbols
88. The amplifiers following the modulated stage in a low level modulation AM system be
(A) linear amplifier (B) harmonic generators (C) class C power amplifiers (D) class untuned amplifiers
89. In a radar system maximum unambiguous range depends on
(A) maximum power of the transmitter (B) pulse repetition frequency
(C) width of the transmitted pulse (D) sensitivity of the radar receiver.
90. In composite video waveform the function of the serrations, is to
(A) equalize the charge in the integrator before the start of vertical retrace
(B) help vertical synchronization (D) simplify the generation of the vertical sync pulse
91. The frequency range 30MHz - 300MHz is
(A) medium frequency (B) very high frequency (C) super high frequency (D) Infrared frequency
92. Which wave cannot exist inside wave guide
(A) TE (B) TM (C) TEM (D) HE
93.Ionosphere layer of earth is situated at
(A) upto 18 kms from earth (B) from 18 to 70 km (C) 70 to 500 km (D) above 500km
94. A two cavity klystron tube is a
(A) velocity modulated tube (B) frequency modulated tube
(C) Amplitude modulated tube (D) simple triode
95. As the thermal noise get doubled due to the increase in a resistance the noise power get.
(A) doubled (B) quadruped (C) unchanged (D) halved.
96.Which one is a cross field tube
(A) Klystron (B) Reflex Klystron (C) Magnetron (D) TWT
97. The degree of coupling depends
(A) size of hole (B) location of holes (C) size and location of holes (D) not depend on size or location of hole
98. The thermal noise depends on
(A) direct current through device
(B) resistive component of resistance
(C) reactive component of impedance
(D) load to connected.
99. The charge on a hole is
(A) 1.6 x 10-9
(B) 1.6 x 10-19
(C) 1.6 x 101
(D) 1.6 x 1020
100. Intel's 8085 microprocessor chip contains
(A) seven 8 bit registers (B) 8 seven bits registers (C) seven 7 bit registers (D) eight 8 bit registers.
ANSWERS
1. (C) 2. (B) 3. (C) 4. (C) 5. (C) 6. (C) 7. (B) 8.(D) 9. (A) 10. (B) 11. (B) 12.(B) 13. (B) 14. (B) 15. (C) 16.(A) 17. (C) 18. (C) 19. (C) 20. (C) 21. (C) 22. (B) 23. (D) 24. (D) 25.(B) 26.(B) 27.(A) 28.(A) 29. (B) 30.(A) 31. (C) 32. (B) 33.(D) 34. (C) 35. (B) 36. (C) 37. (D) 38. (A) 39(C) 40.(C) 41. (A) 42. (B) 43.(C) 44. (C) 45.(C) 46.(B) 47. (C) 48. (C) 49. (C) 50. (B) 51. (A) 52. (B) 53. (C) 54. (C) 55. (C) 56. (B) 57. (D) 58. (A) 59. (B) 60. (D) 61.(A) 62. (A) 63. (D) 64. (B) 65. (D) 66. (D) 67. (C) 68. (D) 69 (D) 70. (D) 71. (B) 72. (C) 73. (D) 74 (D) 75. (C) 76. (C) 77.(C) 78. (D) 79. (A) 80. (D) 81. (A) 82. (C) 83. (C) 84. (C) 85. (C) 86. (C) 87. (B) 88. (C) 89.(B) 90. (C) 91.(B) 92. (C) 93. (C) 94. (A) 95. (C) 96. (C) 97. (B) 98. (B) 99. (B) 100. (A)
1. Modern capacitors which have high capacitance in small size use a dielectric of
(A) paper (B) rubber (C) ceramic (D) Mylar
2. The Maximum spectral response of the germanium andsilicon is in the
(A) infrared region (B) ultraviolet region (C) visible region (D) x-ray region
3. For an insulating material, dielectric strength and dielectric loss should be respectively
(A) high and high (B) low and high (C) high and low (D) low and low.
4. In a distortion factor meter, the filter at the front end is used suppress
(A) odd harmonics (B) even harmonics (C) fundamental component (D) dc component
5. The coefficient of coupling between two air core coils depends on
(A) mutual inductance between two coils only (B) self inductances of the two coils only (C) mutual inductance and self inductances of the two coils (D) none
6. For a parallel plate capacitor which is being charged out of the following the incorrect statement is
(A) Energy stored in the capacitor does not enter it through the connecting wire through the space around the wires and plates of capacitor.
(B) Rate at which energy flows into this volume is equal to the integration of the poynting vector over the boundary of the volume between the plates.
(C) The poynting vector points everywhere radially outward of the volume between plates.
(D) The poynting vector points everywhere radially in to the volume between the plates.
7. The presence of alkali oxides in alumino silicate ceramics is likely to result in dielectric breakdown due to
(A) Polarization (B) Conductivity (C) Structural homogeneties (D) Ionization
8. Which of the following will serve as a donor impurity in silion
(A) Boron (B) Indium (C) Germanium (D) Antimony
9. Electrical contact materials used in switches, brushes and relays must possess
(A) high thermal conductivity and high melting point (B) Low thermal conductivity and low melting point
(C) High thermal conductivity and low melting point (D) Low thermal conductivity and high melting point.
10. An SCR can only be turned off via it's
(A) cathode (B) anode (C) gates (D) none
11.Gold is often diffused into silicon PN junction devices to
(A) increase the recombination rate (B) reduce the recombination rate
(C) make silicon a direct gap semiconductor (D) make silicon semi-metal
12 Withn nodes andb branches a network will have
(A) (b+n) links (B)b - n +1 links (C) b -n-1 links (D)b + n + 1 links
13. When a network has 10 nodes and 17 branches in all then the number of node pair voltages would be
(A) 7 (B) 9 (C) 10 (D) 45
14. In any atom the potential energy of an orbiting electron is
(A) always positive (B) always negative
(C) sometime positive, sometime negative (D) numerically less then its kinetic energy.
15. A delition MOSFET differs from a JFET in the sense that it has no
(A) channel (B) gate (C) P-N junctions (D) substrate
16. The advantage of a semiconductor strain gauge cover the wire round strain guage is that
(A) it is more sensitive (B) it is more linear (C) it is less temperature dependent
(D) it's cost is low
17. Barrier potential in a P-N junction is caused by
(A) thermally generated electrons and holes (B) diffusion of majority carriers across the junction
(C) migration of minority carriers across the junction (D) flow of drift current.
18. When an NPN transistor is properly biased then most of the electrons from the emitter
(A) recombine with holes in the base (B) recombine in the emitter itself
(C) pass through the base to the collector (D) are stopped by the junction barrier
19. The deplition voltage for silicon diode atµ0 bias is
(A) 0.5 volt (B) 0.3 volt (C) 0.7 volt (D) 1.1 volt
20. A UJT can
(A) be triggered by any one of it's three terminals (B) not be triggered
(C) be triggered by two of its three terminal only (D) be triggered by all of its terminals only.
21. The energy of electric field due to a spherical charge distribution of radiusr and inform charge density in vacuum is
22. Maxwells divergence equation for the magnetic field is given by
A. ▼* B = 0
B. ▼. B = 0
__ __
__ __
C. ▼* B = p
D. ▼. B = p
23. When a short grounded vertical antenna has a lengthL which is 0.05 1 at frequencyf and if it's radiation resistances atf isR Ohms, then its radiation resistance at a frequency2f will be
(A)R/2 ohms (B)R ohms (C)2R ohms (D)4R ohms
24.In a cylindrical cavity resonator, the two modes which are degenerate would include
(A)TE111 andTM111
(B)TE011 andTM011
(C)TE022 andTM111
(D)TE111 and TM011
25. When an antenna of input resistance 73 ohm is connected to a 50-ohm line and if the losses are ignored then its efficiency will be nearly
(A) 0.19 (B) 0.81 (C) 0.97 (D) 1.19
26.The transformer utilization factor of full wave bridge rectifier is
(A) 0.812 (B) 0.286 (C) 0.693 (D) 0.782
27. When a dominant mode wave guide not terminated in its characteristic impedance is excited with a 10 GHZ signal then ifd is the distance between two successive minima of the standing wave in the guide then
(A)d = 1.5 cm (B)d is less then 1.5 cm (C)d is greater then 1.5 cm (D)d = 3cm
28. A two port network having a 6 dB loss will give
(A) an output power which is one - quarter of the input power (B) an output power which is one - half of the input power
(C) an output voltage which is 0.707 of the input voltage. (D) an output power which is 0.707 of the input power.
29. While transporting a sensitive galvanometer
(A) the terminals are kept shorted (B) critical damping resistance is connected across the terminals
(C) the terminals are kept open circuited (D) it does not matter as to what is connected across the terminals.
30. A T type attenuator is designed for an attenuation of 40 dB and terminating resistance of 75 ohms.
Which of the following values represent full series armR1 and shunt armR2?
1.R1 = 147 Ω 2.R1 = 153 Ω 3.R1 = 1.5 Ω 4.R1= 3750 Ω
(A) 1 and 3 (B) 1 and 4 (C) 2 and 3 (D) 2 and 4
31. For a transmission line, the characteristic impedance with inductance 0.294µH/m and capacitance 60pF/m is
(A) 49Ω (B) 60Ω (C) 70Ω (D) 140Ω
32. When the graph of a network has six branches with three tree branches then the minimum number of equations required for the solution of the network is
(A) 2 (B) 3 (C) 4 (D) 5
33. Consider the following statement for a 2-port network
1.Z11 =Z22
2.h12 =h21
3.Y12 = -Y21
4.BC - AD = -1
then the network is reciprocal if and only if
(A) 1 and 2 are correct (B) 2 and 3 are correct (C) 3 and 4 are correct (D) 4 alone is correct.
34. As a network contains only independent current sources and resistors then if the values of all resistors are doubled then the values of the node voltages are
(A) will become half (B) will remain unchanged
(C) will become double (D) cannot be determined unless the circuit configuration and the values of the resistors are known.
35. A iron cored choke is a
(A) Linear and active device (B) Non linear and passive device (C) Active device only (D) Linear device only
36. Poynting vector wattmeter is based on
(A) Seebeck effect (B) Ferranti effect (C) Induction effect (D) Hall effect
37. Which one of the following is not a transducer in the true sense?
(A) Thermocouple (B) Piezoelectric pick-up (C) Photo voltaic cell (D) LCD.
38. The term used to denote a static device that converts ac to dc, de to ac, dc to dc or ac to ac is
(A) Converter system (B) Inverter (C) Chopper (D) Thyristor
39. When a dipole antenna of 1/8 length has an equivalent total resistance of 1.5 Watt then the efficiency of the antenna is
(A) 0.89159% (B) 8.9159% (C) 89.159% (D) 891.59%
40. In commercial FM broadcasting, the maximum frequency deviation is normally
(A) 5 KHz (B) 15 KHz (C) 75 KHz (D) 200 KHz
41. Weins bridge is used for measurement of frequency in the applied voltage waveform is measurement of frequency in the applied voltage waveform is
(A)sinusoidal (B) square (C) rectangular (D) triangular
42.Strain gauge is
(A) not a transducer (B) an active transducer (C) not an electronic instrument
43.A highQ coil has
(A) large band width (B) high losses (C) low losses (D) flat response
44. In the case of an instrument reading of 8.3 V with a 0 to 150 voltmeter having a guaranteed accuracy of 1% full scale reading, the percentage limiting error is
(A) 1.810% (B) 0.181% (C)12.45% (D) 0.0018%
45. The 'h' parameter equivalent circuit of a junction transistor is valid for
(A) High frequency, large signal operation (B) High frequency, small signal operation (C) Low frequency, large signal operation.
46. A system is causal if the output of any time depends only on
(A) Values of input in the past and in the future (B) Values of input at that time and in the past
(C) Values of input at that time and in the future (D) none
47. Form the hot metal surface electrons escape because
(A) of change of state from metal to gas due to heat. (B) of change of state from gas to metal (C) the energy supplied is greater than the work function (D) the energy is greater than Fermi level
48. The most common device used for detection in radio receivers is
(A) amplifier (B) triode (C) diode (D) transistor
49. In a full wave rectifier the negative point in a circuit is
(A) cathode (B) anode (C) The central tap on the high voltage secondary (D) plate.
50.Negative feedback amplifier has a signal corrupted by noise as its input. The amplifier will
(A) Amplify the noise as much as the signal (B) Reduce the noise (C) Increase the noise
(D) Not effect the noise
PART - II
51. It is an unidirectional device that blocks the current flow from cathode to anode
(A) SCR (B) PCR (C) VCR (D) DCR
52. An ideal constant current source is connected in series with an ideal constant voltage source. Considering together the combination will be a
(A) constant voltage source (B)constant current source
(C) constant voltage and a constant current source or a constant power source. (D) resistance
53. Anode current in an thyristor is made up of
(A) electrons only (B) electrons or holes (C) electrons and holes (D) holes only
54. For a pulse transformer, the material used for its core and the possible turn ration from primary to secondary are respectively
(A) ferrite : 20 : 1 (B) laminated iron : 1 :1 (C) ferrite : 1 : 1 (D) powered iron : 1: 1
55. A converter which can operate in both 3 pulse and 6 pulse mode is a
(A) 1 phase full converter (B) 3 phase half wave converter (C) 3 phase semiconverter (D) 3 phase full converter.
56. A single phase CSI has capacitor C as the load. For a constant source current, the voltage across the capacitor is
(A) square wave (B) triangular wave (C) step function (D) pulsed wave
57. a single phase full wave midpoint thyristor converter uses a 230/200V transformer with centre tap on the secondary side. The P.I.V per thyristor is
(A) 100V (B)141.4V (C)200V (D)282.8V
58. In dc choppers for chopping period T, the output voltage can be controlled by FM by varying
(A)T keepingTon constant (B)Ton keepingT constant
(C)Toff keepingT constant (D) None of the above
59.An ideal power supply consist of
(A) Very small output resistance (B) Zero Internal resistance
(C) Very large input resistance (D) Very large output resistance
60. The linearity error for a digital input is indicated by
(A) ξ (B) γ (C) η (D) ε
61. In the 8421 BCD code the decimal number 125 is written as
(A)1111101 (B) 0001 0010 0101 (C) 7D (D) None of the bove
62. Match the given feedback circuit with its proper nomenclatures
(A) Current series feedback (B) Current shunt feedback
(C) Voltage series feedback (D) Voltage shunt feedback
63. Class A amplifier is used when
(A) No phase inversion is required (B) Highest voltage gain is required
(C) dc voltages are to be amplified (D) Minimum distortion is desired.
64. Identity the correct match for the given transister
(A) Enhancement type P channel MOSFET (B) Depletion type N channel MOSFET
(C) Enhancement type N channel MOSFET (D) Depletion type P channel MOSFET
65. In case a signal band limited to fermimeter is sampled at a rate less than 2 fermimeter, the constructed signal will be
(A) Distortionless (B) Small in amplitude (C) Having higher frequencies suppressed (D) Distorted
66.IC which has quad 2 input AND gates
(A) 7411 (B) 7404 (C)7400 (D) 7408
67. Registers in which data is entered or taken out in serial form are referred as
(A) left shift register (B) right shift register (C) shift registers (D) none of the above
68. The expression ABC can be simplified to
__ __ __
A. A B C
B. AB+BC+CA
__
__ __ __
C. AB+ C
C. A + B + C
69. Read the following
(i) Routh Herwitz's criterion is in time domain
(ii)Root locus plot is in time domain
(iii) Bode plot is in frequency domain
(iv) Nyquist criterion is in frequency domain.
(A) 2,3 and 4 are correct (B) 1,2 and 3 are correct (C) 3 and 4 are correct (D) all four are correct
70. Register and counters are similar in the sense that they both
(A) count pulses (B) store binary operation (C) shift operation
(C) made from an array of flip flops and gates integrated on a single chip.
71. InD/A converter, the resolution required is 50mv and the total maximum input is 10v. The number of bits required is
(A) 7 (B) 8 (C) 9 (D) 200
72. On different unit impulse function results in
(A) Unit parabolic function (B) Unit triplet (C) Unit doublet (D) Unit ramp function
73. ........... watt of power is received from sun per m2 surface area of a geosynchronous satellite
(A) 100 (B) 500 (C) 2000 (D) 1000
74. The ripple factor in an LC filter.
(A) Increases with the load current (B) Increases with the load resistance
(C) Remains constant with the load current (D) Has the lowest value
75. In different parts of the country identical telephone numbers are distinguished by their
(A) Language digits (B) Access digits (C) Area codes (D) Central office codes
76.Amplitude modulation is used for broadcasting because
(A) it is move noise immune than other modulation systems
(B) compared with other systems it requires less transmitting power
(C) its use avoids receiver complexity
(D) no other modulation system can provide the necessary bandwidth for high fidelity.
77. The maximum phase shift that can be provided by a lead compensator with transfer function.
1+6S
G0(S) =______
1+2S
(A) 15o
(B) 45o
(C) 30o
(D) 60o
78. The correct sequence of steps required to improve system stability is
(A) Insertderivative action, use negative feedback, reduce gain (B) Reduce gain, use negative feedback, insert derivative action (C) Reduce gain, insert derivative action, use negative feedback (D) Use negative feedback, reduce gain, insert derivative action,
79. Identity slope change atω = 10 of the magnitudev/s frequency characteristic of a unity feedback system with the following open-loop transfer function.
A -80 dB/dec to -60 dB/dec
B 40 dB/dec to 20 dB/dec
C 20 dB/dec to -40 dB/dec
D 40 dB/dec to -20 dB/dec
80. In the feedback control system the loop transfer function is given by K
G(s)H(s)=_____________
S(s+2)(s2+2s+2) Number of asymptotes of its root loci is
A. 1 B. 2
C. 3
D. 4
81. In a closed - loop transfer function
G(s)
2600 k(s+25)
____= _____________________________
H(s)
s4+125s3+5100s2+65000s+65000 k
A. ±j228 B. ±j2.28 C. ±j1.14 D. j114
82. Considering the following statement : In a magic tee
1. the collinear arms are isolated from each other
2. one of the collinear is isolated from the E-arm
3. one of the collinear arm is isolated from the H-arm
4. E-arm and H-arm are isolated from each other. Of these statements
(A) 1 and 2 are correct (B) 1 and 3 are correct (C) 1 and 4 are correct (D) 2 and 3 are correct.
83. In 1965 first geostationary satellite was launched called
(A) ANIK (B) EARLY BIRD (Intel sat - 1) (C) WESTAR (D)MOLNIYA
84. When A = 0., B = 0, C = 1 then in two input logic gate we get gate
(A) XOR gate (B) AND gate (C) NAND gate (D) NOR gate
85. In a radio receiver the IF amplifier
(A) is tuned above the stations incoming frequency (B) amplifies the output of local oscillator
(C) is fixed tuned to one particular frequency (D) can be tuned to various isolate frequencies
86. A duplexer is used to
(A) Couple two antennas to a transmitter without interference
(B) isolate the antenna from the local oscillator
(C) prevent interference between two antennas connected to a receiver
(D) use an antenna for reception or transmission without interference.
87. Boolean algebra is based on
(A) numbers (B) logic (C) truth (D) symbols
88. The amplifiers following the modulated stage in a low level modulation AM system be
(A) linear amplifier (B) harmonic generators (C) class C power amplifiers (D) class untuned amplifiers
89. In a radar system maximum unambiguous range depends on
(A) maximum power of the transmitter (B) pulse repetition frequency
(C) width of the transmitted pulse (D) sensitivity of the radar receiver.
90. In composite video waveform the function of the serrations, is to
(A) equalize the charge in the integrator before the start of vertical retrace
(B) help vertical synchronization (D) simplify the generation of the vertical sync pulse
91. The frequency range 30MHz - 300MHz is
(A) medium frequency (B) very high frequency (C) super high frequency (D) Infrared frequency
92. Which wave cannot exist inside wave guide
(A) TE (B) TM (C) TEM (D) HE
93.Ionosphere layer of earth is situated at
(A) upto 18 kms from earth (B) from 18 to 70 km (C) 70 to 500 km (D) above 500km
94. A two cavity klystron tube is a
(A) velocity modulated tube (B) frequency modulated tube
(C) Amplitude modulated tube (D) simple triode
95. As the thermal noise get doubled due to the increase in a resistance the noise power get.
(A) doubled (B) quadruped (C) unchanged (D) halved.
96.Which one is a cross field tube
(A) Klystron (B) Reflex Klystron (C) Magnetron (D) TWT
97. The degree of coupling depends
(A) size of hole (B) location of holes (C) size and location of holes (D) not depend on size or location of hole
98. The thermal noise depends on
(A) direct current through device
(B) resistive component of resistance
(C) reactive component of impedance
(D) load to connected.
99. The charge on a hole is
(A) 1.6 x 10-9
(B) 1.6 x 10-19
(C) 1.6 x 101
(D) 1.6 x 1020
100. Intel's 8085 microprocessor chip contains
(A) seven 8 bit registers (B) 8 seven bits registers (C) seven 7 bit registers (D) eight 8 bit registers.
ANSWERS
1. (C) 2. (B) 3. (C) 4. (C) 5. (C) 6. (C) 7. (B) 8.(D) 9. (A) 10. (B) 11. (B) 12.(B) 13. (B) 14. (B) 15. (C) 16.(A) 17. (C) 18. (C) 19. (C) 20. (C) 21. (C) 22. (B) 23. (D) 24. (D) 25.(B) 26.(B) 27.(A) 28.(A) 29. (B) 30.(A) 31. (C) 32. (B) 33.(D) 34. (C) 35. (B) 36. (C) 37. (D) 38. (A) 39(C) 40.(C) 41. (A) 42. (B) 43.(C) 44. (C) 45.(C) 46.(B) 47. (C) 48. (C) 49. (C) 50. (B) 51. (A) 52. (B) 53. (C) 54. (C) 55. (C) 56. (B) 57. (D) 58. (A) 59. (B) 60. (D) 61.(A) 62. (A) 63. (D) 64. (B) 65. (D) 66. (D) 67. (C) 68. (D) 69 (D) 70. (D) 71. (B) 72. (C) 73. (D) 74 (D) 75. (C) 76. (C) 77.(C) 78. (D) 79. (A) 80. (D) 81. (A) 82. (C) 83. (C) 84. (C) 85. (C) 86. (C) 87. (B) 88. (C) 89.(B) 90. (C) 91.(B) 92. (C) 93. (C) 94. (A) 95. (C) 96. (C) 97. (B) 98. (B) 99. (B) 100. (A)
