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ECE :: Electromagnetic Field Thoery

  1. For an elliptically polarized wave incident on the interface of a dielectric at the Brewster angle the reflected wave will be

  2. A.
    elliptically polarized
    B.
    linearly polarized
    C.
    right circularly polarized
    D.
    left circularly polarized

  3. The phase velocity in a transmission line is

  4. A.
    B.
    v = LC
    C.
    v = LC
    D.

  5. Which of the antenna is best excited by a waveguide?

  6. A.
    Horn
    B.
    Discone
    C.
    Helical
    D.
    Biconical

  7. An end fire array consisting of several half-wave lengths of directive gain 40, then array length will be

  8. A.
    10 λ
    B.
    100 λ
    C.
    20 λ
    D.
    5 λ

  9. Loop antennas are mostly employed for direction finding (DF) purposes because they are small and hence portable.

  10. A.
    True
    B.
    False

  11. The troposphere extends from earth surface to a height of

  12. A.
    15 km
    B.
    90 km
    C.
    150 km
    D.
    200 km

  13. Antenna reciprocity is put to use in

  14. A.
    radar system
    B.
    commercial broadcast
    C.
    TV broadcast system
    D.
    none of the above

  15. The length of a λ/2 antenna in feet is given by the relation


  16. For satellite communication, the frequency should be

  17. A.
    equal to the critical frequency
    B.
    more than the critical frequency
    C.
    less than the critical frequency
    D.
    none of these

  18. The velocity of electromagnetic wave in free space is given by

  19. A.
    μ00
    B.
    μ0 . ε0
    C.
    D.
    ε00