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ECE :: Microwave Communication

  1. The domain mode in rectangular waveguide is

  2. A.
    TE01
    B.
    TE02
    C.
    TE10
    D.
    TM11

  3. The reverse voltage applied to a varactor diode

  4. A.
    is less than avalanche breakdown voltage
    B.
    is more than avalanche breakdown voltage
    C.
    may be more or less than a avalanche breakdown voltage
    D.
    is very high as compared to avalanche breakdown voltage

  5. To ensure that only dominant mode TE10 is allowed to propagate in an air filled rectangular waveguide, the lower frequency limit and upper frequency limit are

  6. A.
    about 25% above fc for TE10 and 5% below fc for TE20 mode respectively
    B.
    about 50% above fc for TE10 and 25% below fc for TE20 mode respectively
    C.
    about 25% above fc for TE10 and 25% below fc for TE20 mode respectively
    D.
    none of the above

  7. The skin depth at 1000 MHz as compared to that at 500 MHz is

  8. A.
    2
    B.
    12
    C.
    0.707
    D.
    0.5

  9. The transit time (in cycles) for electrons in repeller space of reflex klystron oscillator for sustaining oscillations is (n is any integer)

  10. A.
    2(n - 1)
    B.
    2n - 1
    C.
    D.

  11. In a TWT the amplitude of resultant wave travelling down the helix remains constant

  12. A.
    True
    B.
    False

  13. In the given figure forward current wave has a magnitude of

  14. A.
    0.45 A
    B.
    0.3 A
    C.
    0.2 A
    D.
    0.1 A

  15. In an infinite line the input impedance at every point is equal to characteristic impedance.

  16. A.
    True
    B.
    False

  17. Consider the following time parameters

    1. Domain growth time constant.
    2. Transit time.
    3. Dielectric relaxation time in positive mobility regime.
    Which of the above are used in connection width transferred electron device?

  18. A.
    1, 2, and 3
    B.
    1 and 2 only
    C.
    1 and 3 only
    D.
    2 and 3 only

  19. PIN diode has

  20. A.
    p+ and n layers separated by i layer
    B.
    p+ and n+ layers separated by i layer
    C.
    p- and n- layers separated by i layer
    D.
    none of the above