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ECE :: Microwave Communication

  1. A coaxial RF cable has a characteristic impedance of 50 Ω and C equal to 40 pF/m. The inductance is

  2. A.
    1 μ H/m
    B.
    10 μ H/m
    C.
    0.1 μ H/m
    D.
    0.01 μ H/m

  3. In a microwave coaxial line, the maximum operating frequency is f max and breakdown strength of dielectric is Ed' Then maximum power handling capacity is proportional to


  4. To couple a coaxial line to a parallel wire line it is best to use

  5. A.
    slotted line
    B.
    balun
    C.
    directional coupler
    D.
    λ/4 transformer

  6. In a multicavity klystron amplifier the signal to be amplified develops an ac voltage of signal frequency across the gap in buncher cavity

  7. A.
    True
    B.
    False

  8. If VSWR is infinite, the transmission line is terminated in

  9. A.
    short circuit
    B.
    complex impedance
    C.
    open circuit
    D.
    either (a) or (c)

  10. In a circular waveguide TE21 mode has lowest cutoff frequency

  11. A.
    True
    B.
    False

  12. The number of TV channels which can be accommodated in a spectrum of 300 MHz is about

  13. A.
    5
    B.
    10
    C.
    50
    D.
    200

  14. The noise figure of multicavity klystron amplifier is very low

  15. A.
    True
    B.
    False

  16. Assertion (A): The velocity of electromagnetic waves on overhead lines and coaxial cables is the same.

    Reason (R): Free space has an intrinsic impedance of 377 ohms.

  17. A.
    Both A and R are correct and R is correct explanation of A
    B.
    Both A and R are correct but R is not correct explanation of A
    C.
    A is correct but R is wrong
    D.
    A is wrong but R is correct

  18. In the given figure the E and H lines in a coaxial cable

  19. A.
    The radial lines are E lines and circular lines are H lines
    B.
    Radial lines are H lines and circular lines are E lines
    C.
    The directions of E and H lines are wrong
    D.
    Radial lines may be E and H lines depending an direction of current