Electromagnetic Field Theory MCQ

Test your knowledge with important Electromagnetic Field Theory MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30+ more Electromagnetic Field Theory MCQs on Bissoy. Bissoy App

• Which of the following impedance inversion is obtained?
  ক

  Short-circuited stub

  খ

  A quarter wave line

  গ

  Balun transformer

  ঘ

  A half wave line
• Radiation intensity in a given direction is the
  ক

  Energy radiated per square metre

  খ

  Power radiated per square metre

  গ

  Power radiated per unit solid angle in that direction

  ঘ

  None of the above
• The wave in wave guide has
  ক

  Group velocity inversely proportional to wavelength

  খ

  Larger frequency than in the free space

  গ

  Diminishing wavelength than in the free space

  ঘ

  Larger wavelength than in the free space
• A waveguide operated below cut off frequency can be used as
  ক

  Phase shifter

  খ

  An attenuator

  গ

  An isolator

  ঘ

  None
• The attenuation in waveguide above to cut off frequency
  ক

  Very high

  খ

  Very low

  গ

  Zero

  ঘ

  Infinite
• MUF is highest in periods of greatest sunspot activity.
  ক

  True

  খ

  False
• The power gain of a half-wave dipole with respect to an isotropic radiator is
  ক

  2.15 db

  খ

  3 db

  গ

  4.15 db

  ঘ

  6 db
• In microwave communication links, when fading due to rain attenuation occurs then technique adopted for solving the problem would include
  ক

  Antenna replacement and feed correction

  খ

  Amplitude timing and phase correction

  গ

  Polarization shifting and code diversity

  ঘ

  Path diversity and frequency diversity
• A square corner reflector is used in
  ক

  Radio astronomy

  খ

  Tv broadcast

  গ

  Point to point communication

  ঘ

  All of the above
• The main disadvantage of the two-hole directional coupler is
  ক

  Poor directivity

  খ

  Narrow bandwidth

  গ

  High standing wave ratio

  ঘ

  Low directional coupling
• A satellite that simply reflect back the signals from one region of the earth to the other region is known as
  ক

  Orbiting satellite

  খ

  Geostationary satellite

  গ

  Active satellite

  ঘ

  Passive satellite
• When the phase velocity of an EM wave depends on frequency in any medium the phenomenon is called
  ক

  Scattering

  খ

  Polarisation

  গ

  Absorption

  ঘ

  Dispersion
• The useful magnetic flux obtainable from any closed surface is
  ক

  Unity

  খ

  Constant

  গ

  Both A and B

  ঘ

  None of the above
• Due to which of the following reasons a lightning conductor on top of a building is made into a pointed spike?
  ক

  Dust particles may not accumulate

  খ

  Charge per unit area becomes very high for lightening to discharge

  গ

  Rain drops may not collect

  ঘ

  None of the above
• When a wave is incident from the more dense into a less dense medium at an angle equal to or exceeding the critical angle, the wave suffers total internal __________ .
  ক

  Reflection

  খ

  Refraction

  গ

  Transmission

  ঘ

  None of the above
• If a and b are the dimensions of waveguide then
  ক

  a = 3b

  খ

  a = 2b

  গ

  a = b

  ঘ

  $${\text{a}} = \frac{{\text{b}}}{4}$$
• When a current carrying conductor is brought into magnetic field, the force that moves the conductor depends upon
  ক

  The value of current

  খ

  The weight of the conductor

  গ

  The direction of the conductor

  ঘ

  None of the above
• The radiation pattern of loop antenna is
  ক

  Circle

  খ

  Semicircle

  গ

  Elliptical

  ঘ

  Cardoid or Limacon
• MUF is depend upon
  ক

  Electron density of the ionospheric layer

  খ

  11 year sun spot cycle

  গ

  Received frequency by receiver

  ঘ

  Height of ionospheric layer
• Parabolic and lens antenna used at
  ক

  Microwave frequency

  খ

  Medium frequency

  গ

  Low frequency

  ঘ

  High frequency
• The skip distance is the maximum distance upto which ionospheric reflection is possible.
  ক

  True

  খ

  False
• The static electric field in a conductor is
  ক

  Zero

  খ

  Unity

  গ

  Infinity

  ঘ

  None of the above
• The frequency range for satellite communication is
  ক

  3 to 30 kHz

  খ

  300 to 3000 kHz

  গ

  3000 to 30000 MHz

  ঘ

  30000 to 300000 MHz
• In case of antenna the ratio of the power radiated in the desired direction to the power radiated in the opposite direction is known as
  ক

  Transmission efficiency

  খ

  Front to back ratio

  গ

  Loss coefficient

  ঘ

  None of the above
• A Yagi antenna has a driven antenna
  ক

  Only

  খ

  With a reflector

  গ

  With one or more directors

  ঘ

  With a reflector and one or more directors
• Tropospheric scatter is used with frequencies in the
  ক

  HF

  খ

  VHF

  গ

  UHF

  ঘ

  VLF
• A rectangular waveguide is a
  ক

  Rectangular conducting wire to propagate electromagnetic waves

  খ

  Hollow rectangular walled room carrying electromagnetic wave

  গ

  Hollow rectangular conducting tube through which electromagnetic waves can be propagat-ed

  ঘ

  Tube antenna to transmit and receive electromagnetic waves
• Which of the following statement regarding waveguides is incorrect?
  ক

  At waveguide can be coupled to a coaxial cable

  খ

  At frequencies below the cut off value the wave progresses across the waveguide after total reflections

  গ

  Waveguides are usually air filled hollow conducting metallic tubes for transmitting UHF and microwaves

  ঘ

  Waveguides can handle large power at UHF and microwaves
• Which of the following is multiband HF receiving antenna?
  ক

  Square loop

  খ

  Log-periodic

  গ

  Conical horn

  ঘ

  Folded dipole
• In H-plane metal plate lens the travelling wave front is
  ক

  Totally retarded

  খ

  Retarded

  গ

  Accelerated

  ঘ

  Neither accelerated nor retarded