Antenna And Wave Propagation 1
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Attempt Free Antenna And Wave Propagation 1 Here. Read The Important Electrical MCQ From Below.
1) What is the wavelength of Super high frequency (SHF) especially used in Radar & satellite communication?
a. 1 m – 10 m
b. 1 cm – 10 cm
c. 10 cm – 1 m
d. 0.1 cm – 1 cm
ANSWER: 1 cm – 10 cm
2) Which among the following is an application of high frequency?
a. SONAR
b. Subsurface communication
c. Radio navigation
d. Facsimile
ANSWER: Facsimile
3) Wave front is basically a locus of points acquiring similar _______
a. Phase
b. Frequency
c. Amplitude
d. Wave equation
ANSWER: Phase
Antenna And Wave Propagation 1
4) In which kind of waveform is the phase velocity defined?
a. Sinusoidal
b. Rectangular
c. Square
d. Triangular
ANSWER: Sinusoidal
5) Which among the following is/are not present in free space?
a. Solid bodies
b. Ionized particles
c. Interference of normal radiation & radio wave propagation
d. All of the above
ANSWER: All of the above
6) Power density is basically termed as ________ power per unit area
a. Reflected
b. Refracted
c. Radiated
d. Diffracted
ANSWER: Radiated
7) If the path difference of two waves with single source traveling by different paths to arrive at the same point, is λ/2, what would be the phase difference between them?
a. β x (λ/2)
b. β / (λ/2)
c. β + (λ/2)
d. β – (λ/2)
ANSWER: β x (λ/2)
Antenna And Wave Propagation 1
8) Which ionization layer exists during day time & usually vanishes at night due to highest recombination rate?
a. D-region
b. Normal E-region
c. Sporadic E-region
d. Appleton region
ANSWER: D-region
9) What is the possible range of height for the occurrence of sporadic E-region with respect to normal E-region?
a. 20 km – 50 km
b. 45 km – 85 km
c. 90 km – 130 km
d. 140 km – 200 km
ANSWER: 90 km – 130 km
10) F2 layer of appleton region acts as a significant reflecting medium for _____ frequency radio waves
a. Low
b. Moderate
c. High
d. All of the above
ANSWER: High
Antenna And Wave Propagation 1
11) The knowledge of which parameter is sufficient for deriving the time varying electromagnetic field?
a. Electric field intensity
b. Magnetic field intensity
c. Current density
d. Power density
ANSWER: Current density
12) According to Webster’s dictionary, what is an antenna?
a. Impedance matching device
b. Sensor of electromagnetic waves
c. Transducer between guided wave & free space wave
d. Metallic device for radiating or receiving radio waves
ANSWER: Metallic device for radiating or receiving radio waves
13) Under which conditions of charge does the radiation occur through wire antenna?
a. For a charge with no motion
b. For a charge moving with uniform velocity with straight & infinite wire
c. For a charge oscillating in time motion
d. All of the above
ANSWER: For a charge oscillating in time motion
Antenna And Wave Propagation 1
14) In a non-isotropic directional antenna, which radiating lobe axis makes an angle of 180° w.r.t. major beam of an antenna?
a. Minor lobe
b. Side lobe
c. Back lobe
d. None of the above
ANSWER: Back lobe
15) At which angles does the front to back ratio specify an antenna gain?
a. 0° & 180°
b. 90° & 180°
c. 180° & 270°
d. 180° & 360°
ANSWER: 0° & 180°
16) Which among the following defines the angular distance between two points on each side of major lobe especially when the radiation drops to zero?
a. Half power beam width (HPBW)
b. First null beam width (FNBW)
c. Side lobe level (SLL)
d. Front to back ratio (FBR)
ANSWER: First null beam width (FNBW)
Antenna And Wave Propagation 1
17) If an observation point is closely located to the source, then the field is termed as ________
a. Induced
b. Radiated
c. Reflected
d. Far-field
ANSWER: Induced
18) Which auxiliary functions assist in solving the radiation problem by evaluation of E & H using sources J & M?
a. Scalar potentials
b. Vector potentials
c. Gradient potentials
d. Divergence potentials
ANSWER: Vector potentials
19) Which operations are performed by vector potentials (A, F) over the radiated fields (E & H)?
a. Addition
b. Subtraction
c. Differentiation
d. Integration
ANSWER: Differentiation
20) Which waveform plays a crucial role in determining the radiation pattern of the dipole/wire antennas?
a. Current
b. Voltage
c. Frequency
d. Phase
ANSWER: Current
Antenna And Wave Propagation 1
21) How are the infinitesimal dipoles represented in terms of antenna length and signal wavelength?
a. l ≤ (λ /50)
b. (λ/50 ) < l ≤ (λ /10)
c. l = λ/2
d. None of the above
ANSWER: l ≤ (λ /50)
22) In flared transmission line, the radiation phenomenon increases due to ________ in flaring
a. Increase
b. Decrease
c. Stability
d. None of the above
ANSWER: Increase
23) Which pattern is generated due to plotting of square of amplitude of an electric field?
a. Field Pattern
b. Voltage Pattern
c. Power Pattern
d. All of the above
ANSWER: Power Pattern
Antenna And Wave Propagation 1
24) In an electrically small loops, the overall length of the loop is ______ one-tenth of a wavelength.
a. Less than
b. Equal to
c. Greater than
d. None of the above
ANSWER: Less than
25) On which factor/s do/does the radiation field of a small loop depend?
a. Shape
b. Area
c. Both a and b
d. None of the above
ANSWER: Area
26) From the radiation point of view, small loops are _________radiators
a. Poor
b. Good
c. Better
d. Excellent
ANSWER: Poor
27) According to the directivity of a small loop, which value of ‘θ’ contributes to achieve the maximum value of radiation intensity (Umax)?
a. 0°
b. 90°
c. 180°
d. 270°
ANSWER: 90°
Antenna And Wave Propagation 1
28) In which kind of array configuration, the element locations must deviate or adjust to some nonplaner surface like an aircraft or missile?
a. Linear
b. Planer
c. Conformal
d. All of the above
ANSWER: Conformal
29) What is the nature of radiation pattern of an isotropic antenna?
a. Spherical
b. Dough-nut
c. Elliptical
d. Hyperbolic
ANSWER: Spherica
30) In broadside array, all the elements in the array should have similar _______excitation along with similar amplitude excitation for maximum
radiation.
a. Phase
b. Frequency
c. Current
d. Voltage
ANSWER: Phase
31) Which among the following is regarded as a condition of an ordinary endfire array?
a. α < βd
b. α > βd
c. α = ±βd
d. α ≠ ±βd
ANSWER: α = ±βd
Antenna And Wave Propagation 1
32) Which mode of propagation is adopted in HF antennas?
a. Ionospheric
b. Ground wave
c. Tropospheric
d. All of the above
ANSWER: Ionospheric
33) For which band/s is the space wave propagation suitable over 30 MHz?
a. VHF
b. SHF
c. UHF
d. All of the above
ANSWER: All of the above
34) If the tower antenna is not grounded, which method of excitation is/are applicable for it?
a. Series
b. Shunt
c. Both a and b
d. None of the above
ANSWER: Series
Antenna And Wave Propagation 1
35) In ungrounded antennas, if an excitation is applied directly across the base insulator, then on which factor/s would the voltage across the insulator depend?
a. Power delivered to antenna
b. Power factor of impedance
c. Both a and b
d. None of the above
ANSWER: Both a and b
Antenna And Wave Propagation 1
