Home / ECE / Electromagnetic Field Thoery :: Section 7

ECE :: Electromagnetic Field Thoery

  1. Short-circuited stubs are used, because open-circuited stubs are

  2. A.
    liable to radiate
    B.
    complex in nature
    C.
    providing open-circuit environments
    D.
    unable to provide work over large frequency range

  3. Directivity and beamwidth is related as

  4. A.
    D ∝ B
    B.
    D ∝ 1/B
    C.
    D ∝ B
    D.
    D ∝ B2

  5. An arrangement of several individual antennas to spaced and phased that their individual contributions combine in one preferred direction and cancel in all other directions, to get greater directive gain or directivity, is known as

  6. A.
    directional radiation of antennas
    B.
    antenna gain stability
    C.
    array of antennas
    D.
    none of the above

  7. The complex Poynting vector for electromagnetic wave.

  8. A.
    Im(E x Hx)
    B.
    Re(E x Hx)
    C.
    (E x H)
    D.
    E x H

  9. 300 to 3000 MHz frequency is categorized as

  10. A.
    MF
    B.
    HF
    C.
    UHF
    D.
    SHF

  11. The gain of an antenna with a circular aperture of diameter 3 metres at a frequency of 5 GHz, will be

  12. A.
    2.4674
    B.
    24.674
    C.
    246.74
    D.
    24674

  13. The gain of a current element is

  14. A.
    0 dB
    B.
    1.67 dB
    C.
    1.76 dB
    D.
    3 dB

  15. Poynting theorem relates the electric intensity E, magnetic intensity H to the rate of energy flow per unit area at a point P as

  16. A.
    P = E/H
    B.
    P = H/E
    C.
    E = 1/E x H
    D.
    P = E x H

  17. The absorption of EM wave by the atmosphere depends on

  18. A.
    polarization of waves
    B.
    frequency in use
    C.
    dist. from Ty
    D.
    height of antenna