logo

CuriousTab

CuriousTab

Discussion

Home ‣ Electronics and Communication Engineering ‣ Microwave Communication See What Others Are Saying!
  • Question

  • Assertion (A): Magnetron is generally used in n mode.

    Reason (R): Frequency for p mode can be easily separated from adjacent modes.


  • Options
  • 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

  • Correct Answer
  • Both A and R are correct and R is correct explanation of A 

    Explanation
    It is somewhat similar to TWT and can deliver microwave power over a wide frequency band.

    It has an electron gun and a helix structure. However the interaction between electron beam and RF wave is different than in TWT.

    The growing RF wave travels in opposite direction to the electron beam.

    The frequency of wave can be changed by changing the voltage which controls the beam velocity.

    Moreover the amplitude of oscillations can be decreased continuously to zero by changing the beam current.

    It features are:

    1. Frequency range - 1 GHz to 1000 GHz.

    2. Power output - 10 mV to 150 mW (continuous wave) 250kW (pulsed).

    It is used as signal source in transmitters and instruments.

    More questions

    • 1. The power requirements of a DRAM in active and stand by modes is about

    • Options
    • A. 350 mW and 5 mW respectively
    • B. 350 mW each
    • C. 5 mW each
    • D. 350 mW and 100 mW respectively
      • Discuss
    • 2. The different access methods which permit many satellite users to operate in parallel through a single transponder without interfering with each other as

    • Options
    • A. Frequency Division Multiple Access (FDMA)
    • B. Time Division Multiple Access (TDMA)
    • C. Code Division Multiple Access (CDMA)
    • D. All of the above
      • Discuss
    • 3. Match the following:

      List I List II
      A. T (Reflection coefficient) = 0 1. (ZL - Zo)/(ZL + Zo)
      B. T = - 1 2. ZL = Zo
      C. T = + 1 3. ZL = 0
      D. - 1 < T < + 1 4. ZL = ?


    • Options
    • A. A-2, B-3, C-4, D-1
    • B. A-2, B-4, C-1, D-3
    • C. A-1, B-2, C-3, D-4
    • D. A-3, B-2, C-4, D-1
      • Discuss
    • 4. Assertion (A): Ferromagnetic materials possess ferromagnetic properties only when temperature is less than paramagnetic curie temperature.

      Reason (R): For a ferromagnetic material for T > ?f.


    • Options
    • A. Both A and R are true and R is correct explanation of A
    • B. Both A and R are true but R is not correct explanation of A
    • C. A is true but R is false
    • D. A is false but R is true
      • Discuss
    • 5. Bode magnitude plot is drawn between

    • Options
    • A. magnitude of network function and ?
    • B. dB magnitude and log ?
    • C. dB magnitude and ?
    • D. loge (magnitude) and log ?
      • Discuss
    • 6. A two branch parallel circuit has a 20 ? resistance and 1 H inductance in one branch and a 100 ?F capacitor in the second branch. It is fed from 100 V ac supply, at resonance, the input impedance of the circuit is

    • Options
    • A. 500 ?
    • B. 50 ?
    • C. 20 ?
    • D. 5 ?
      • Discuss
    • 7. The temperature coefficient of a thermistor

    • Options
    • A. is positive
    • B. is negative
    • C. zero
    • D. may be positive or negative depending on its composition
      • Discuss
    • 8. An amplifier has a large ac input signal. The clipping occurs on both the peaks. The output voltage will be nearly a

    • Options
    • A. sine wave
    • B. square wave
    • C. triangular wave
    • D. (a) or (c)
      • Discuss
    • 9. In the figure shown, A1, A2, A3 are identical Ammeters. If A1 and A3 read 5 and 13 A respectively, reading of A2 will be

    • Options
    • A. 8
    • B. 13 A
    • C. 18
    • D. 12 A
      • Discuss
    • 10. A relaxation oscillator uses

    • Options
    • A. tunnel diode
    • B. UJT
    • C. both tunnel diode and UJT
    • D. PIN diode
      • Discuss

    Comments

    There are no comments.
Enter a new Comment




Aptitude

Engineering

Programming

Reasoning

Links

Copyright ©CuriousTab. All rights reserved.