Home / ECE / Electromagnetic Field Thoery :: Section 9

ECE :: Electromagnetic Field Thoery

  1. The portion of the atmosphere closest to ground is called ionosphere.

  2. A.
    True
    B.
    False

  3. Which of the following relations is valid for a spherical surface?

  4. A.
    B.
    C.
    D.
    None of the above

  5. When there is rapid attenuation of field inside the conductor, the field current are concentrated close to the surface of the conductor; this phenomenon is called

  6. A.
    skin effect
    B.
    EM concentration effect
    C.
    Faraday's effect
    D.
    Ohm's effect

  7. Which antenna is frequently used for local area transmission at UHF/VHF?

  8. A.
    Ground monopole
    B.
    Turnstile antenna
    C.
    Slot antenna
    D.
    Loop antenna

  9. The work done in moving a charge Q on an equipotential line for a distance d will be

  10. A.
    V/d
    B.
    QV/d
    C.
    Q.d
    D.
    zero

  11. For frequency up to 1650 kHz, the transmitting antenna is used a

  12. A.
    parabolic dish
    B.
    vertical antenna
    C.
    yagi antenna
    D.
    turnstile antenna

  13. Radar antennas are

  14. A.
    dipoles
    B.
    helical
    C.
    parabolic
    D.
    conical

  15. Which of the following is high frequency transmission line?

  16. A.
    An impedance transformer
    B.
    Frequency compensator
    C.
    Flying resistor
    D.
    None of the above

  17. Which of the following are the properties of a medium?

  18. A.
    Permeability, flux, magnesium
    B.
    Permittivity, permeability, insulation
    C.
    Permeability, resistivity, conductivity
    D.
    Permittivity, permeability, conductivity

  19. In microwave communication, some times, microwave signals reach large distances by following the earth curvature. This phenomenon is called

  20. A.
    tropospheric scatter
    B.
    faraday effect
    C.
    ionospheric reflection
    D.
    ducting