Quiznetik

Dynamics of Machinery | Set 2

1. From the given data, calculate the unbalanced centrifugal force in N s2 Distance from shaft = 0.2 m Mass = 100 kg Rotating speed = 1000 rpm.

Correct : C. 200

2. Let the disturbing mass be 50 Kg, with radius of rotation = 0.1m, if one of the balancing mass is 30 Kg at a radius of rotation 0.1m then find the other balancing mass situated at a distance of 0.2m.

Correct : D. 10

3. In the given figure, m1=20 Kg, m2=30Kg and m=50 Kg, if r1=0.2m and r=0.3m, l=1m, find l2.

Correct : A. 0.26m

4. What is the function of frequency analyzer?

Correct : B. It analysis noise signal in frequency domain into various frequency bands by electronically separating the signal

5. What is the function of the controller in active vibration isolation systems?

Correct : C. Interpret detected vibrations and execute commands

6. Temperature monitoring technique uses which of the following devices to measure temperature of the machining surfaces?

Correct : D. All of the above

7. Which of the following statements is true about stroboscope?

Correct : A. Stroboscope is non-contact type frequency instrument

8. Which type of frequency measuring instrument has multiple reeds of different natural frequency to measure vibrations?

Correct : B. Frahm Tachometer

9. Which of the following instruments measure amplitude of a vibrating body?

Correct : C. Both a. and b.

10. Which of the following vibrometers have frequency ratio (ω/ωn) << 1?

Correct : A. Accelerometers

11. Which type of monitoring system uses stroboscope to measure speed of the machine?

Correct : B. Basic condition monitoring system

12. Seismometer can be used to measure acceleration of any instrument only if _____

Correct : C. both a. and b.

13. In FFT Spectrum Analyzer, the D/A converter is used to ________.

Correct : D. converts digital signals into analog signals

14. In FFT Spectrum Analyzer, the A/D converter is used to ________.

Correct : C. convert analog signals into digital signals

15. In FFT Spectrum Analyzer, the attenuator is used to ________.

Correct : B. sets the level of the signals to be fed to the A/D converter

16. In FFT Spectrum Analyzer, the filter is used to ________.

Correct : A. reject unwanted signals

17. FFT analyzer can be used to find the ___________.

Correct : C. both natural frequencies and mode shapes

18. Fourier transform is a mathematical procedure to obtain the __________ of a given input signal.

Correct : A. spectrum

19. In FFT Spectrum Analyzer, FFT stands for _______.

Correct : D. Fast Fourier Transform

20. From the following, which one is used in an accelerometer?

Correct : B. Piezoelectric crystals

21. The accelerometers are commonly used in vibration measurement due to their ___________.

Correct : D. small size and high sensitivity

22. Which instrument is used to record building vibrations or vibrations of huge structures like railway bridges?

Correct : C. Vibrometer

23. Vibration measuring instruments are classified on the basis of ____________.

Correct : D. all of the above

24. From the following, which one is also known as low-frequency Transducer?

Correct : C. Vibrometer

25. From the following, which one is a type of vibration measuring instrument?

Correct : D. All of the above

26. An accelerometer is an instrument used to measure the _________ of a vibrating body.

Correct : C. acceleration

27. Stroboscope is used for the measurement of _________________?

Correct : A. Rpm of a flywheel

28. A seismometer is a device used to measure the ___________ of a vibrating body.

Correct : A. displacement

29. The instruments which are used to measure the ___________ of a vibrating body are called vibration measuring instrument.

Correct : D. all of the above

30. The accelerometer is used as a transducer to measure earthquake in Richter scale. Its design is based on the principle that ______.

Correct : C. its natural frequency is equal to the frequency of vibration

31. Which of the following instruments measure the amplitude of a vibrating body?

Correct : C. Both (a) and (b)

32. Which of the following systems produce a vibration in the foundation?

Correct : D. Unbalanced machine

33. What does the accelerometer measure?

Correct : B. Acceleration

34. Which of the following device can be used for measurement of frequency?

Correct : C. Stroboscope

35. Which of the following is correct regarding isolation factor?

Correct : A. Dimensionless quantity

36. If the damper is not provided and the system is in resonance, which of the following is the correct isolation factor?

Correct : D. Infinity

37. Which part of human ear converts sound vibrations into electrical signals

Correct : D. Cochlea

38. Sound is measured by units that are called

Correct : B. Decibels (dB)

39. 'Eardrum' bursts at

Correct : C. 160 dB

40. The loudness of sound varies directly with the vibrating body's

Correct : B. Amplitude

41. The scale to measure the intensity level of sound is called

Correct : D. decibel scale

42. Pitch of the sound depends upon

Correct : A. Frequency

43. Noise is

Correct : D. all of the above

44. Following scale is used for loudness of sound or noise

Correct : B. Logarithmic scale

45. Sound Intensity is given by.

Correct : A. I=w/s

46. Unit for Reference sound intensity is_________.

Correct : A. W/m2

47. Sound power of a machine whose specified sound power level is 125 dB

Correct : A. 3.16 w

48. The process of maintaining appropriate noise level without considering economic factors is called as _____

Correct : B. noise reduction

49. Basic elements of noise control are

Correct : A. Source ,Path ,Receiver of noise

50. All sound is noise.

Correct : B. False

51. Main sources of noise pollution are

Correct : D. Transportation equipment and heavy machinery

52. The sound can travel in air when:

Correct : C. Disturbance travel from one place to another

53. White noise is random noise that has a audible frequency rangefrom

Correct : B. 20 to 20KHtz

54. Which among the following has a constant power spectral density over a wide frequency range?

Correct : A. White noise

55. Which is correct option for ear protection equipment?

Correct : C. Ear defeders ,Ear plugs

56. The technique or method to absorb undesirable sounds by soft and porous

Correct : A. Acoustic protection

57. When sound interacts with materials and boundaries, it displays all the

Correct : B. Waves

58. Soft materials absorb a large amount of

Correct : D. Sound energy

59. Reflection coefficient (Γ) is the rario of intensity of sound ______________.

Correct : A. Reflected / Incident.

60. Absorption coefficient (α) is the rario of intensity of sound ______________.

Correct : C. Absorbed / Incident.

61. Which best describe the sound wave?

Correct : C. It is always longitudinal

62. Which of the following can not travel through a vacuum?

Correct : C. Sound wave

63. Through which medium does sound travel fastest?

Correct : B. Steel

64. Sound wave has two main characteristics which are

Correct : A. Pitch and loudness

65. When waves bend away from straight lines of travel, it is called

Correct : D. Refraction

66. _________ is the sound power measured over the area upon which is received.

Correct : C. Sound intensity

67. It is an audio transducer that converts acoustic pressure in air into its equivalent electrical impulses

Correct : D. Microphone

68. _________ is a pressure type microphone with permanent coil as a transducing element.

Correct : A. Dynamic

69. A capacitor stores energy in the form of an electrostatic field is a ______.

Correct : B. Condenser Microphone

70. A microphone that uses the piezoelectric effect

Correct : C. Crystal

71. It describes the output of a microphone over a range of frequencies.

Correct : C. Frequency response

72. The most important terms that are used to describe the sound field around a sound emitting object

Correct : C. A and B both

73. The sound waves behave in a much more complex fashion, and there is no fixed relationship between ________________.

Correct : B. pressure and distance

74. The sound far field is beginning at a distance of ____________ .

Correct : D. 2 wavelengths away from the sound source

75. Measurement of noise can be made in following environment ____________

Correct : D. All the above