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ECE :: Electromagnetic Field Thoery

  1. Which one is correct option?

  2. A.
    TEM mode exist in free space of infinite boundary
    B.
    TEM mode exist in two conductor pattern system for finite-boundary
    C.
    TEM mode exist in waveguide only
    D.
    Both (a) and (b)

  3. A vertical loop antenna, like a horizontal dipole, is vertically polarised.

  4. A.
    True
    B.
    False

  5. The attenuation in a waveguide near the cut off frequency is

  6. A.
    zero
    B.
    low
    C.
    high
    D.
    very high

  7. The electric flux and field intensity inside a conducting sphere is

  8. A.
    minimum
    B.
    maximum
    C.
    uniform
    D.
    zero

  9. T.V. antennas are usually

  10. A.
    Yagi-Uda
    B.
    loops
    C.
    helical
    D.
    parabolic

  11. Measurement of radiation resistance by reflection method is suitable for

  12. A.
    parasitic element antennas
    B.
    low frequency vertical conductor antenna
    C.
    all type of antennas
    D.
    none of the above

  13. A lossless transmission line is connected to two identical voltage source as shown in figure.

    The impedance measured at the midpoint AA' is

  14. A.
    B.
    100
    C.
    50
    D.
    25

  15. A loss less transmission line is terminated in a load which reflects a part of the incident power. The measured VSWR is 2. The percentage of the power that is reflected back is

  16. A.
    57.73
    B.
    33.33
    C.
    0.11
    D.
    11.11

  17. A higher directivity is specified by

  18. A.
    high gain low BW (Beamwidth)
    B.
    high gain high BW
    C.
    low gain high BW
    D.
    none of the above

  19. The best excited reflector from a wave guide is

  20. A.
    horn
    B.
    parabolic
    C.
    biconical
    D.
    corner