Antenna And Wave Propagation 2 ELECTRONICS IMPORTANT MCQ PDF

Antenna And Wave Propagation 2

1)   According to depth of penetration, what is the percentage proportion of attenuated wave w.r.t its original value?
a. 17%
b. 27%
c. 37%
d. 57%

ANSWER: 37%

2)   Linear polarization can be obtained only if the wave consists of ________
a. Ex
b. Ey
c. Both Ex & Ey & in phase
d. Both Ex & Ey & out of phase

ANSWER: Both Ex & Ey & in phase

3)   When an electromagnetic wave travels from transmitter to receiver, which factor/s affect/s the propagation level?
a. Curvature of earth
b. Roughness of earth
c. Magnetic field of earth
d. All of the above

ANSWER: All of the above

Antenna And Wave Propagation 2

4)   For avoiding ground losses, better is the surface conductivity, less is the __________
a. Attenuation
b. Phase velocity
c. Propagation constant
d. Tilt angle

ANSWER: Attenuation

5)   On which factors of earth does the magnitude of tilt angle depend in surface wave?
A. Permittivity
B. Conductivity
C. Resistivity
D. Reflectivity
a. A & B
b. C & D
c. A & C
d. B & D

ANSWER: A & B

Antenna And Wave Propagation 2

6)   What is the direction of varying orientation of polarized surface wave at the earth surface in a wave tilt mechanism?
a. Horizontal
b. Vertical
c. Diagonal
d. Opposite

ANSWER: Vertical

7)   Which layer has the atmospheric conditions exactly opposite to that of standard atmosphere?
a. Depression layer
b. Regression layer
c. Inversion layer
d. Invasion layer

ANSWER: Inversion layer

8)   If the maximum electron density for F-layer in ionosphere is 4 x 106 electrons/cm3, then what will be the critical frequency of EM wave for F-layer?
a. 4 MHz
b. 9 MHz
c. 18 MHz
d. 25 MHz

ANSWER: 18 MHz

Antenna And Wave Propagation 2

9)   According to Secant law, which frequency is greater than critical frequency by a factor of secθi?

a. MUF
b. LUF
c. OWF
d. UHF

ANSWER: MUF

10)   How is the effect of selective fading reduced?
A. By high carrier reception
B. By low carrier reception
C. By single side band system
D. By double side band system
a. A & C
b. B & D
c. A & D
d. B & C

ANSWER: A & C

Antenna And Wave Propagation 2

11)   In lens antenna, what kind of wave energy is transformed into plane waves?
a. Convergent
b. Divergent
c. Contingent
d. Congruent

ANSWER: Divergent

12)   What is the functioning role of an antenna in receiving mode?
a. Radiator
b. Converter
c. Sensor
d. Inverter

ANSWER: Sensor

13)   In radio communication link, what is the shape/nature of waves generated by transmitting antenna?
a. Spherical
b. Plane
c. Triangular
d. Square

ANSWER: Spherical

Antenna And Wave Propagation 2

14)   Which among the following elucidate the generation of electromagnetic waves?
A. Ampere’s law
B. Faraday’s law
C. Gauss’s law
D. Kirchoff’s law
a. A & B
b. B & C
c. A & C
d. B & D

ANSWER: A & B

15)   If an antenna draws 12 A current and radiates 4 kW, then what will be its radiation resistance?
a. 22.22 ohm
b. 27.77 ohm
c. 33.33 ohm
d. 39.77 ohm

ANSWER: 27.77 ohm

Antenna And Wave Propagation 2

16)   Under which conditions of two unit vectors, the polarization loss factor (PLF) is equal to unity?
a. Perpendicular
b. Perfectly aligned
c. Angle inclination (Ψp)
d. All of the above

ANSWER: Perfectly aligned

17)   Which property/ies of antenna is/are likely to be evidenced in accordance to Reciprocity theorem?
a. Equality of impedances
b. Equality of directional patterns
c. Equality of effective lengths
d. All of the above

ANSWER: All of the above

18)   Self impedance of an antenna is basically __________
a. Its input impedance during the removal of all other antennas
b. Its impedance by taking into consideration the consequences of other antennas
c. Both a and b
d. None of the above

ANSWER: Its input impedance during the removal of all other antennas

19)   In solution evaluation process of inhomogeneous vector potential wave equation, if points are completely removed from the source, then by which factor does the time varying field & static solution differ?
a. e-jkr
b. ejkr
c. e-jk/r
d. e(jk + r)

ANSWER: e-jkr

Antenna And Wave Propagation 2

20)   Which among the below mentioned magnetic quantities is/are dependent on media/medium?
a. B
b. H
c. Both a and b
d. None of the above

ANSWER: B

21)   The concept of magnetic vector potential finds its major application in deriving expression of magnetic field intensity especially for ______
a. Real fields
b. Imaginary fields
c. Complex fields
d. None of the above

ANSWER: Complex fields

22)   If J & M are active at the same time, which principle theorem is used for field estimation?
a. Reciprocity
b. Superposition
c. Causality
d. Relativity

ANSWER: Superposition

Antenna And Wave Propagation 2

23)   A dipole carries r.m.s. current of about 300A across the radiation resistance 2 Ω. What would be the power radiated by an antenna?
a. 90 kW
b. 135 kW
c. 180 kW
d. 200 kW

ANSWER: 180 kW

24)   What is/are the major applications of an infinitesimal dipole that contribute/s to its analysis?
a. Field pattern estimation due to any length of antenna
b. Improvement in radiation resistance by increasing dipole length
c. Both a and b
d. None of the above

ANSWER: Both a and b

25)   What is /are the advantages of using ferrite loops?
A. Increase in Magnetic field intensity
B. Increase in radiation resistance
C. Decrease in Magnetic field intensity
D. Decrease in radiation resistance
a. A & B
b. C & D
c. A & D
d. B & C

ANSWER: A & B

Antenna And Wave Propagation 2

26)   In an electrically large loop, an overall length of the loop is equal to ______
a. λ/2
b. λ
c. λ/10
d. λ/50

ANSWER: λ

27)   How do the elements of an active region behave?
a. Inductive
b. Capacitive
c. Resistive
d. None of the above

ANSWER: Resistive

28)   By how many times is an input impedance of a folded dipole at resonance greater than that of an isolated dipole with same length as one of its sides?
a. 2
b. 3
c. 4
d. 6

ANSWER: 4

Antenna And Wave Propagation 2

29)   Which mode of radiation occurs in an helical antenna due to smaller dimensions of helix as compared to a wavelength?
a. Normal
b. Axial
c. Both a and b
d. None of the above

ANSWER: Normal

30)   A rectangular horn antenna operating at 4GHz has the wavelength of 0.075m and gain of about 13dBi. What will be its required capture area?
a. 0.0149 m2
b. 0.0475 m2
c. 0.5521 m2
d. 0.9732 m2

ANSWER: 0.0149 m2

Antenna And Wave Propagation 2