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This section includes 247 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
51. |
Indicate which one of the following modes do not exist in a rectangularresonantcavity |
A. | te110 |
B. | tm110 |
C. | te011 |
D. | mt111 |
Answer» B. tm110 | |
52. |
Calculate the transmission coefficient, when the incident and transmitted amplitudes are10 and 7 respectively. |
A. | 17 |
B. | 3 |
C. | 10/7 |
D. | 0.7 |
Answer» E. | |
53. |
Find the characteristic impedance of a quarter wave with input and load impedances given by50 and 25 respectively. |
A. | 50 |
B. | 25 |
C. | 75 |
D. | 35.35 |
Answer» E. | |
54. |
Propagation constant γ is given by: |
A. | α+jβ |
B. | α-jβ |
C. | α/jβ |
D. | α.jβ |
Answer» B. α-jβ | |
55. |
Indicate the false statement. The SWR on a transmission line is infinity; the line isterminated in |
A. | a short circuit |
B. | an open circuit |
C. | a complex impedance |
D. | pure reactance |
Answer» D. pure reactance | |
56. |
If a transmission line of a characteristics impedance 50 Ω is terminated with a loadimpedance of 100 Ω, then the reflection co efficient is: |
A. | 0.3334 |
B. | 0.6667 |
C. | 1.6 |
D. | 1.333 |
Answer» B. 0.6667 | |
57. |
Maxwell’s equation for electromagnetic waves in a waveguide is: |
A. | ∇×e = -jωµ(vector h) |
B. | ∇×e =-jωμ(vector e) |
C. | ∇×h=-jωμ(vector h) |
D. | ∇×h=jωμ(vector h) |
Answer» B. ∇×e =-jωμ(vector e) | |
58. |
Expression for the characteristic impedance of a transmission line(λ/4) used for impedance matching is: |
A. | z1=√(zₒr)l |
B. | z1=√(zₒ/r)l |
C. | z1=√(zₒ+r)l |
D. | none of the mentioned |
Answer» B. z1=√(zₒ/r)l | |
59. |
If a device is passive and contains no anisotropic elements, then the deviceis_______ network. |
A. | reciprocal |
B. | non reciprocal |
C. | lossless |
D. | lossy |
Answer» B. non reciprocal | |
60. |
ency of 30GHz is (free space impedance 0 =377 Ω) |
A. | 308 Ω |
B. | 400 Ω |
C. | 355 Ω |
D. | 461 Ω |
Answer» C. 355 Ω | |
61. |
When the electric field applied to GaAs specimen is less than the threshold electricfield, the current in the material: |
A. | increases linearly |
B. | decreases linearly |
C. | increases exponentially |
D. | decreases exponentially |
Answer» B. decreases linearly | |
62. |
If a transmission line of characteristic impedance 50 Ω is terminated with a loadimpedance of 150 Ω , then VSWR is: |
A. | 0.75 |
B. | 0.5 |
C. | 2 |
D. | none of the mentioned |
Answer» B. 0.5 | |
63. |
The junction resistance and capacitance of the intrinsic region in a PIN diode areconnected______ in the equivalent circuit of PIN diode. |
A. | series |
B. | parallel |
C. | connected across package capacitance |
D. | none of the mentioned |
Answer» C. connected across package capacitance | |
64. |
Power dividers and couplers are ______ microwave components used for powerdivision or power combining. |
A. | passive |
B. | active |
C. | linear |
D. | non linear |
Answer» B. active | |
65. |
The radar in which both transmission and reception is done using the sameantenna are called: |
A. | monostatic |
B. | bistatic |
C. | dipole radar |
D. | monopole radar |
Answer» B. bistatic | |
66. |
_________ and __________ contribute to the impedance of a transmission line in thelumped element representation. |
A. | resistor, inductor |
B. | resistor, capacitor |
C. | capacitor, inductor |
D. | transistor, capacitor |
Answer» B. resistor, capacitor | |
67. |
Processing in MMICs is done by __________ |
A. | ion implantation |
B. | net list generation |
C. | floor planning |
D. | none of the mentioned |
Answer» B. net list generation | |
68. |
For the capacitors used in MMICs, the insulating dielectric films used are: |
A. | air |
B. | sio |
C. | titanium |
D. | gaas |
Answer» C. titanium | |
69. |
The substrate of an MMIC must be a _____________ to accommodate the fabrication of all the type of devices. |
A. | semiconductor |
B. | insulator |
C. | partial conductors |
D. | metals operable at high frequencies |
Answer» B. insulator | |
70. |
The maximum theoretical output circuit efficiency of a double resonator klystron amplifier is |
A. | 25% |
B. | 50% |
C. | 58% |
D. | 85% |
Answer» D. 85% | |
71. |
Which of the following is not possible in a circular wave guide ? |
A. | te10 |
B. | te01 |
C. | te11 |
D. | te12 |
Answer» B. te01 | |
72. |
A cavity resonator can be represented by |
A. | an lc circuit |
B. | an lcr circuit |
C. | a lossy inductor |
D. | a lossy capacitor |
Answer» B. an lcr circuit | |
73. |
Ionospheric preparation is not possible for microwaves because |
A. | microwaves will be fully absorbed by the ionospheric layers |
B. | there will be an abrupt scattering in all directions |
C. | microwave will penetrate through the ionospheric layers |
D. | there will be dispersion of microwave energy |
Answer» D. there will be dispersion of microwave energy | |
74. |
When the electric field applied to GaAs specimen is less than the threshold electric field, the current in the material: |
A. | increases linearly |
B. | decreases linearly |
C. | increases exponentially |
D. | decreases exponentially |
Answer» B. decreases linearly | |
75. |
Which of the following can be used for amplification of microwave energy? |
A. | magnetron |
B. | reflex klystron |
C. | traveling wave tube |
D. | gunn diode |
Answer» D. gunn diode | |
76. |
Klystrons operates on the principal of |
A. | amplitude modulation |
B. | frequency modulation |
C. | pulse modulation |
D. | velocity modulation |
Answer» E. | |
77. |
________ is a single cavity klystron tube that operates as on oscillator by using a reflector electrode after the cavity. |
A. | backward wave oscillator |
B. | reflex klystron |
C. | travelling wave tube |
D. | magnetrons |
Answer» C. travelling wave tube | |
78. |
When a reverse bias voltage exceeding the breakdown voltage is applied to an IMPATT diode, it results in: |
A. | break down of depletion region |
B. | avalanche multiplication |
C. | high reverse saturation current |
D. | none of the mentioned |
Answer» C. high reverse saturation current | |
79. |
The width of depletion region of a varactor diode ________with increase in reverse bias voltage. |
A. | increases |
B. | decreases |
C. | remains constant |
D. | none of the mentioned |
Answer» B. decreases | |
80. |
The junction resistance and capacitance of the intrinsic region in a PIN diode are connected______ in the equivalent circuit of PIN diode. |
A. | series |
B. | parallel |
C. | connected across package capacitance |
D. | none of the mentioned |
Answer» C. connected across package capacitance | |
81. |
If a microwave network is lossless, then S matrix of the microwave network is: |
A. | zero matrix |
B. | symmetric |
C. | identity matrix |
D. | unitary |
Answer» E. | |
82. |
If a device is passive and contains no anisotropic elements, then the device is_______ network. |
A. | reciprocal |
B. | non reciprocal |
C. | lossless |
D. | lossy |
Answer» B. non reciprocal | |
83. |
T- junction is an example for: |
A. | 2 port network |
B. | 3 port network |
C. | 4 port network |
D. | none of the mentioned |
Answer» C. 4 port network | |
84. |
Power dividers and couplers are ______ microwave components used for power division or power combining. |
A. | passive |
B. | active |
C. | linear |
D. | non linear |
Answer» B. active | |
85. |
The device commonly used in microwave ovens is the: |
A. | twt |
B. | klystron |
C. | magnetron |
D. | yig |
Answer» D. yig | |
86. |
A “circulator†is a device that: |
A. | rotates signal polarity in a waveguide |
B. | allows a signal to pass in one direction only |
C. | separates signals among various ports |
D. | prevents microwaves from being “trapped†in a waveguide |
Answer» D. prevents microwaves from being “trapped†in a waveguide | |
87. |
Directional coupler for waveguide are characterized by |
A. | insertion loss |
B. | coupling specification |
C. | directivity |
D. | all of the above |
Answer» E. | |
88. |
Ferrite isolators are ____ port microwave devices. |
A. | two |
B. | three |
C. | four |
D. | none of the mentioned |
Answer» B. three | |
89. |
S parameters are expressed as a ratio of: |
A. | voltage and current |
B. | impedance at different ports |
C. | indecent and the reflected voltage waves |
D. | none of the mentioned |
Answer» D. none of the mentioned | |
90. |
TEâ‚’â‚’ mode for a rectangular waveguide: |
A. | exists |
B. | exists but defined only under special cases |
C. | does not exist |
D. | cannot be determined |
Answer» D. cannot be determined | |
91. |
In TM mode, if the direction of wave propagation is in ‘z’ direction, then: |
A. | hz=0 |
B. | ez=0 |
C. | ey=0 |
D. | hy=0 |
Answer» B. ez=0 | |
92. |
The modes of wave propagation that a rectangular waveguide can support are: |
A. | tem, te, modes |
B. | tem,tm, te modes |
C. | tem, tm modes |
D. | te,tm modes |
Answer» E. | |
93. |
Maxwell’s equation for electromagnetic waves in a waveguide is: |
A. | ∇×e = -jωµ(vector h) |
B. | ∇×e =-jωμ(vector e) |
C. | ∇×h=-jωμ(vector h) |
D. | ∇×h=jωμ(vector h) |
Answer» B. ∇×e =-jωμ(vector e) | |
94. |
For co-axial lines and waveguides, ________ is more preferred. |
A. | open circuited stub |
B. | short circuited stub |
C. | slotted section |
D. | co-axial lines cannot be impedance matched |
Answer» C. slotted section | |
95. |
In shunt stub matching, the key parameter used for matching is: |
A. | admittance of the line at a point |
B. | admittance of the load |
C. | impedance of the stub |
D. | impedance of the load |
Answer» B. admittance of the load | |
96. |
Shunt stubs are preferred for: |
A. | strip and microstrip lines |
B. | coplanar waveguides |
C. | circular waveguide |
D. | circulators |
Answer» B. coplanar waveguides | |
97. |
The major advantage of single stub tuning over other impedance matching techniques is: |
A. | lumped elements are avoided |
B. | it can be fabricated as a part of transmission line media |
C. | it involves two adjustable parameters |
D. | all of the mentioned |
Answer» E. | |
98. |
Characteristic impedance of a transmission line is: |
A. | impedance z of a transmission line |
B. | impedance which is a constant at any point on the transmission line |
C. | reciprocal of admittance of a transmission line |
D. | none of the mentioned |
Answer» C. reciprocal of admittance of a transmission line | |
99. |
Transmission line is a _________ parameter network. |
A. | lumped |
B. | distributed |
C. | active |
D. | none of the mentioned |
Answer» C. active | |
100. |
_________ and __________ contribute to the impedance of a transmission line in the lumped element representation. |
A. | resistor, inductor |
B. | resistor, capacitor |
C. | capacitor, inductor |
D. | transistor, capacitor |
Answer» B. resistor, capacitor | |