Electromagnetic Field Theory(Engineering > Electrical Engineering ) Questions and Answers

Question 1. A loop antenna is a commonly used for
  1.    Radar
  2.    Direction finding
  3.    Satellite communication
  4.    All of the above
Explanation:-
Answer: Option B. -> Direction finding
Question 2. The divergence of a vector is a scalar, while the curl of a vector is another
  1.    Scalar
  2.    Vector
  3.    Unit vector
  4.    None of the above
Explanation:-
Answer: Option B. -> Vector
Question 3. Which antenna is a wideband antenna?
  1.    Hertz antenna
  2.    Marconi antenna
  3.    Folded dipole
  4.    None of the above
Explanation:-
Answer: Option C. -> Folded dipole
Question 4. The potential that appears at a point in space due to the current which caused it is called potential
  1.    Accelerating
  2.    Retardation
  3.    Oscillating
  4.    Lagging the current
Explanation:-
Answer: Option B. -> Retardation
Question 5. The minimum height of outer atmosphere is
  1.    100 km
  2.    150 km
  3.    200 km
  4.    400 km
Explanation:-
Answer: Option D. -> 400 km
Question 6. The radiation pattern of a parabola antenna is
  1.    Omnidirectional
  2.    A figure of directional
  3.    Highly directional
  4.    None of the above
Explanation:-
Answer: Option C. -> Highly directional
Question 7. The virtual height of an ionospheric layer is __________ true height
  1.    Equal to
  2.    Less than
  3.    Higher than
  4.    No relation
Explanation:-
Answer: Option C. -> Higher than
Question 8. The transmitting antennas for lower frequencies (below 500 kHz) are generally
  1.    Vertical grounded wire type
  2.    Horizontal suspended wire type
  3.    Parabolic reflector type
  4.    Any of the above
Explanation:-
Answer: Option A. -> Vertical grounded wire type
Question 9. Which of the following will increase the antenna radiation efficiency?
  1.    Use of larger section of conductor
  2.    Providing insulation on conductor
  3.    Top loading of antenna
  4.    Any of the above
Explanation:-
Answer: Option C. -> Top loading of antenna
Question 10. According to maximum power transfer theorem, the maximum power is absorbed by one network from another network when
  1.    The impedance of one of the networks is half that of the other
  2.    The impedance of one is the complex conjugate of the other
  3.    The impedance of one is equal to that of the other
  4.    None of the above
Explanation:-
Answer: Option B. -> The impedance of one is the complex conjugate of the other
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