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ECE :: Electromagnetic Field Thoery

  1. In order to receive a vertical polarized wave, the conductor of the dipole should be mounted

  2. A.
    horizontally
    B.
    vertically
    C.
    at an angle of 45°
    D.
    at an angle of 90°

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  3. VSWR can have any value between

  4. A.
    0 and 1
    B.
    - 1 to + 1
    C.
    0 to ∞
    D.
    1 to ∞

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  5. The input impedance for folded dipole antenna (two half dipole) is

  6. A.
    73 n2
    B.
    377 n2
    C.
    73 n
    D.
    377 n

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  7. What is the characteristic impedance Z0 of a line having R, inductance L, capacitance C and conductance G?

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  9. Capacitance hats are installed on low frequency antenna is

  10. A.
    increase the electrical length
    B.
    reduce the electrical length
    C.
    protect against lightening
    D.
    protect against corona effects

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  11. A ship-to-ship communication system is plagued by fading. The best solution seems to be the use of

  12. A.
    space diversity
    B.
    frequency diversity
    C.
    a broad band antenna
    D.
    a more directional antenna

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  13. Which one of the following is not a correct Maxwell equation?

  14. A.
    B.
    C.
    ∇ x D = f
    D.

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  15. If a wave is propagated in free space, it will be in nature of

  16. A.
    TE
    B.
    TM
    C.
    TEM
    D.
    Any one of above

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  17. When the height of a vertical earthed antenna is less than λ/4

  18. A.
    the base input impedance will be capacitive
    B.
    the base input impedance will be purely resistive
    C.
    the base input impedance will be inductive
    D.
    the base input impedance will be negligibly small

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  19. Which of the following is a circularly polarized antenna?

  20. A.
    Rhombic
    B.
    Circular loop
    C.
    Helical
    D.
    Yagi

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