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ECE :: Electromagnetic Field Thoery

  1. Virtual height of an ionospheric layer is always greater than its actual height.

  2. A.
    True
    B.
    False

  3. In waveguides the existing waves are

  4. A.
    TE only
    B.
    TM only
    C.
    both (a) and (b)
    D.
    all of the above

  5. The term __________ applies to troposcatter propagation

  6. A.
    fading
    B.
    Faraday rotation
    C.
    SIDS
    D.
    atmospheric storms

  7. Unit of e is __________ .

  8. A.
    coulomb/newton-metre
    B.
    coulomb2/newton-metre
    C.
    Farad/metre
    D.
    Farad2/metre

  9. So-called 'grounded' antennas are often found insulated from the ground electrically.

  10. A.
    True
    B.
    False

  11. End fire array is called a linear resonant dipole array.

  12. A.
    True
    B.
    False

  13. Which of the following statements is incorrect regarding Balun transformer?

  14. A.
    It changes impedance like current transformer
    B.
    It changes balanced to unbalanced line
    C.
    It is used to couple a co-axial line to a parallel line wire
    D.
    Any of the above

  15. The maximum usable frequency for the 'E' layer is 10 MHz.

  16. A.
    True
    B.
    False

  17. In free space

  18. A.
    phase velocity is greater than light velocity
    B.
    phase velocity is equal to group velocity
    C.
    phase velocity is equal to light velocity
    D.
    Both (b) and (c)

  19. Laplacian of a scalar function V is

  20. A.
    gradient of V
    B.
    gradient of the gradient of V
    C.
    divergence of V
    D.
    divergence of the gradient of V