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ECE :: Electromagnetic Field Thoery

  1. The value of VSWR is taken as ∞ when the line is

  2. A.
    short-circuited
    B.
    open-circuited
    C.
    terminated with full load
    D.
    terminated with load equal to the characteristic impedance of the load

  3. The wavelength of an electromagnetic wave after reflection at angle on a surface

  4. A.
    remains same as the wavelength perpendicular to the surface
    B.
    remains same in the free space
    C.
    increases in actual direction of propagation
    D.
    decreases in actual direction of propagation

  5. A higher value of Standing Wave Ratio indicates

  6. A.
    least mismatch between line and load
    B.
    greater mismatch between load and line
    C.
    number of nodes is equal to the number of antinodes
    D.
    none of the above

  7. An end fire array consisting of several half-wave lengths of directive gain 40, then Find width of major lobe for broadside

  8. A.
    B.
    5.73
    C.
    51.25
    D.

  9. A wavelength of 1 mm could be expected in

  10. A.
    VLF
    B.
    HF
    C.
    EHF
    D.
    SHF

  11. The numerical value of directivity of current element of half-wave dipole is 1.76 and 2.15 dB respectively. The directive gain of half-wave dipole over current element will be

  12. A.
    3.91 dB
    B.
    1.95 dB
    C.
    0.39 dB
    D.
    0.195 dB

  13. The maximum effective aperture of an antenna which is operating at wavelength of 2 m and has directivity of 100 is

  14. A.
    15.92
    B.
    31.84
    C.
    2.18
    D.
    3.184

  15. The waveguides compared to equivalent transmission lines at low frequency are

  16. A.
    able to carry more power
    B.
    less noisy
    C.
    having lower attenuation
    D.
    all of the above

  17. The current distribution of a half wave dipole is

  18. A.
    uniform
    B.
    sinusoidal
    C.
    triangular
    D.
    complex

  19. In case of static electric field Maxwell's divergence equation states that:

  20. A.
    ∇ . = 1/r
    B.
    ∇ . = r0
    C.
    ∇ . = εr
    D.
    ∇ . = r