Microwave Communication Multiple Choice Questions and Answers PDF Download

Microwave Communication MCQ Quiz Questions and Answers | Microwave Communication  Questions and Answer | Microwave Communication MCQ PDF 

Microwave Communication MCQ Quiz: In this page, we have updated 40 Microwave Communication  Questions and Answer. The transmission of signals by sending microwaves, either directly/through a satellite. Before starting the MCQ quiz, please read the simple definition of Microwave Communication. The receivers for microwave signals are usually disc-shaped antennae from a foot to a few feet across and are often seen installed in business locations or near private homes. Those who want know the Microwave Communication MCQ Quiz Questions and Answers please use this page. Microwaves are electromagnetic waves with relatively long wavelengths and low frequencies. Recent days most of candidates are searching for Microwave Communication Multiple Choice Questions and Answers. This is important subject for ECE. Aspirants who are Preparing for the ECE Board Exam/interview/placement and various competitive examinations kindly use this Microwave Communication MCQ

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MCQ in Microwave Communication 

1.  Which of the following is used as a high power microwave oscillator?

  1. Klystron
  2. Magnetron
  3. Thyratron
  4. Reflex-klystron

Answer: Magnetron

2. A magnetron is operated at a duty cycle of 0.001. It has a peak power output of 100 kilo-watts. Its average power is__________

  1. 1,000 watts
  2. 100 watts
  3. 10,000 watts
  4. None

Answer: 100 watts

3. Which of the following is used as an oscillator device in the SHF band?

  1. Tunnel diode
  2. Thyratron tube
  3. Klystron tube
  4. Both 1 & 2

Answer: Both 1 & 2

4. Microwave frequencies are normally regarded as those in the range of____________

  1. 1000 to 10,000 GHz
  2. 1 to 500 MHz
  3. 10 to 1000 GHz

Answer: 1 to 100 GHz

5. __________ is the progressive decrease of signal strength with increasing distance.

  1. Modulation
  2. Attenuation
  3. Radiation
  4. Propagation

Answer: Attenuation

6. Coupling into and out of a traveling-wave tube can be accompanied by a___________

  1. Waveguide match
  2. Direct coax-helix match
  3. Cavity match
  4. All of the above

Answer: All of the above

7. What do you call an attenuation that occurs over many different wavelengths of the carrier?

  1. Rician fading
  2. Wavelength fading
  3. Rayleigh fading
  4. Slow fading

Answer: Slow fading

8. If the duration of the radar transmitted pulse, on a particular range of operation, is increased, the required bandwidth of the receiver’s IF amplifiers

  1. May be decreased
  2. Must be increased
  3. Must remain as before
  4. Must be doubled

Answer: May be decreased

9. The main frequency determining element of a klystron is__________

  1. Its resonant cavity
  2. The accelerating voltage
  3. The repeller voltage
  4. Its mode of operation

Answer: Its resonant cavity

10. The frequency of the oscillation generated by a magnetron, is mainly determined by__________

  1. The number of the cavity resonators
  2. The ratio of the dc cathode voltage to the magnetic flux density
  3. The dimension of each cavity resonator
  4. The flux density of the external magnet

Answer: The dimension of each cavity resonator

11. Which of the following operating frequencies is used for the modern loran navigational system?

  1. Loran D: 10.2 kHz
  2. Loran A: 1950 kHz
  3. Loran B: 900 kHz
  4. Loran C: 100 kHz

Answer: Loran C: 100 kHz

12. In a pulsed radar set, the function of the duplexer is to____________

  1. Prevent frequency drift in the klystron
  2. Aid in calibrating the display unit
  3. Allow the transmitter and the receiver to operate from a common antenna
  4. None

Answer: Allow the transmitter and the receiver to operate from a common antenna

13. Which of the following permits a microwave signal to travel in one direction with virtually no loss, but severely attenuates any signal attempting to travel in the reverse direction?

  1. Wave trap
  2. Circulator
  3. Tunnel diode

Answer: Isolator

14. When used in conjunction with a radar set, the purpose of an echo box is to provide an artificial target.

  1. Which may be used to tune the radar receiver
  2. To the tone of the pulse repetition
  3. Which may be used to tune the radar synchronizer
  4. Tune the magnetron to the correct frequency

Answer: Which may be used to tune the radar receiver

15. As the electron beam moves through a klystron’s intracavity drift space___________

  1. Velocity modulation at the input cavity creates density modulation at the output cavity
  2. Frequency modulation at the input cavity creates velocity modulation at the output cavity
  3. Phase modulation at the input cavity creates velocity modulation at the output cavity
  4. Density modulation at the input cavity creates velocity modulation at the output cavity

Answer: Velocity modulation at the input cavity creates density modulation at the output cavity

16. The coarse frequency adjustment of a reflex klystron is accomplished by____________

  1. Adjusting the flexible wall of the resonant cavity
  2. An adjustment in the synchronizer
  3. Varying the repeller voltage
  4. The AFC system

Answer: Adjusting the flexible wall of the resonant cavity

17. Klystron oscillators are most often used in the frequency range of___________

  1. 30 to 30000 MHz
  2. 300 to 3000 MHz
  3. 10 to 10000 MHz

Answer: 3000 to 30000 MHz

18. The maximum usable range of the usual radar set (on any particular range setting) is determined by____________

  1. The interval between transmitted pulses
  2. The width of the transmitted pulses
  3. The bandwidth of the receiver IF stages
  4. The duty cycle

Answer: The interval between transmitted pulses

19. When it is desired that short-range targets be clearly seen on a pulsed-radar set, it is important that the receiver and display system have__________

  1. Low-pass filters
  2. A long time constant
  3. The restricted high-frequency response
  4. The shortest possible time

Answer: The shortest possible time

20. If k-factor is greater than 1, the array beam is bent___________

  1. Towards the ionosphere
  2. Away from the earth
  3. Towards the outer space
  4. Towards the earth

Answer: Towards the earth

21. A Class-S Emergency Position-Indicating Radio Beacon (E.P.I.R.B)__________

  1. Must have its battery replaced after emergency use
  2. May be tested during the first five minutes of any hour
  3. All of above

Answer: All of Above

22. Which causes multipath or frequency selective fading?

  1. Further reflector
  2. Nearer reflector
  3. Small reflector
  4. Large reflector

Answer: Large reflector

23. The aquadag coating on the inside of PPI tube is used__________

  1. As a second anode and to prevent the build-up of secondary field
  2. To shield the electron beam from unidirectional magnetic
  3. To focus the beam of primary electrons
  4. All of above

Answer: As a second anode and to prevent the build-up of secondary field

24. A thin layer of dirt and grime coverts the reflecting surface of the parabolic dish of a radar set. The particular effect on the performance of the radar will be

  1. A decrease in range
  2. A reduction in horizontal resolution
  3. A decrease in gain

Answer: No noticeable effect

25. In a pulsed radar set, the STC circuit is used to__________

  1. Improve the target bearing resolution
  2. Vary the pulse frequency in order to control the maximum target
  3. Increases receiver sensitivity for echoes from targets
  4. Reduce interference from the effects of sea return

Answer: Reduce interference from the effects of sea return

26. Which of the reception problems below that is not due to multipath?

  1. Rayleigh fading
  2. Slow fading
  3. Delayed spreading
  4. Random Doppler shift

Answer: Slow fading

27. What allow microwave to pass in only one direction?

  1. Capacitor
  2. Ferrite emitter
  3. RF emitter

28. Rainfall is an important factor for fading of radio waves at frequencies above____________

  1. 100 GHz
  2. 1 GHz
  3. 10 GHz

Answer: 10 GHz

29. A traveling-wave tube (TWT) amplifies by virtue of___________

  1. The energy contained the cavity resonators
  2. The effect of an external magnetic field
  3. The absorption of energy by the signal from an electron stream
  4. The energy liberated form the collector

Answer: The absorption of energy by the signal from an electron stream

30. A shipboard equipment which measures the distance between the ship’s bottom and the ocean floor.

  1. Echosounder
  2. Fathometer
  3. SONAR
  4. LORAN

Answer: SONAR

31. If the instantaneous RF potentials on the two sides of a magnetron cavity are of opposite polarity, the operation is in the_________

  1. 2π mode
  2. π/2mode
  3. π4 mode
  4. π mode

Answer: π mode

32. Calculate the effective earth’s radius if the surface refractivity is 301.

  1. 6370 mi
  2. 8493 mmi
  3. 6370 km

Answer: 8493 km

33. The resonant frequency of a cavity resonator depends upon___________

  1. The mode of operation

Answer: Its physical dimensions

34. A high-power microwave pulse of the order of megawatts can be generated by a________

  1. Magnetron
  2. Traveling-wave tube
  3. Reflex klystron
  4. Gunn diode

Answer: Magnetron

35. Oscillators of a klystron tube are maintained_________

  1. By bunches of electrons passing the cavity grids
  2. By circulating bunches of electrons within the cavities

Answer: By bunches of electrons passing the cavity grids

36. In an SHF pulsed radar set, a reflex klystron can be used as a___________

  1. Local oscillator
  2. Transmitter oscillator
  3. Single mixer stage
  4. Duplexer stage

Answer: Local oscillator

37. The highest frequency which a conventional vacuum tube oscillator can generate is not limited by the__________

  1. Distributed lead inductance
  2. Inter-electrode capacitance
  3. Electron transit time
  4. Degree of emission from the cathode

Answer: Degree of emission from the cathode

38. A PPI cathode-ray tube as used on a radar set________

  1. Indicates both the range and azimuth of a target
  2. Indicates only the range of a target
  3. Is used to check the percentage of modulation
  4. Is used for receiver alignment

Answer: Indicates both the range and azimuth of a target

39. To achieve good bearing resolution when using a pulsed-radar set, an important requirement is___________

  1. A narrow, antenna-beam width in the horizontal plane
  2. A low repetition rate
  3. A narrow, antenna-beam width in the vertical plane
  4. A high duty cycle

Answer: A narrow, antenna-beam width in the horizontal plane

40. It is possible to increase the maximum range of a radar equipment by_________

  1. Raising the peak power of the transmitter
  2. Lowering the pulse frequency
  3. Narrowing the beam width and increasing the pulse duration
  4. All of these

Answer: All of above

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