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Multi-Choice Questions

In document Ultrasonic Testing - Training Notes (Page 59-80)

1. What is the most common manual ultrasonic testing technique in NDT? a. Immersion

b. Through Transmission c. Tandem

d. Pulse Echo

2. In which area of the ultrasonic sound beam do the edges of the wave diverge? a. The Fresnel Zone

b. The Fraunhoffer Zone

c. Inside the damping material d. In the Dead Zone

3. What is the purpose of a couplant?

a. To enable sound energy to pass from the probe to the test piece b. To protect the test piece

c. To lubricate the test piece d. All the above

4. At an interface, when a compression wave in the second medium reaches a refracted angle of 90˚, the incident angle in the first medium is described as…

a. The reflected angle b. The first critical angle c. The second critical angle d. The probe angle

5. Which circuit in an ultrasonic flaw detector controls the timing of the pulses and the creation of the timebase?

a. The pulse generator b. The sweep circuit c. The receiver amplifier

d. The suppression or reject circuit

6. Which of the following reference reflectors does the DGS or AVG system usually use? a. Vee notch

b. Square notch c. Transverse hole d. Flat bottom hole

7. Which of the following are acceptable sizing methods for use with angle probes? a. 6 dB drop

b. 20 dB drop

c. Maximum Amplitude d. All of the above

8. Which component of the ultrasonic test equipment is responsible for the production of the ultrasonic vibrations?

a. The Probe

b. The Flaw detector c. The OPT

d. The calibration block

9. What effect on beam spread does a change of probe, to one with the same diameter but a lower frequency, have?

a. The half angle increases b. The half angle decreases c. a and b

d. Probe frequency does not affect the beam spread

10. Which of the following statements best describes attenuation? a. The resistance of a material to the passage of ultrasound b. The difference in sound intensity of two signals on the CRT c. The increase or decrease in amplifier gain on the flaw detector d. The loss of intensity of sound as it passes through a material

11. At an interface, when a shear wave in the second medium reaches a refracted angle of 90˚, the incident angle in the first medium is described as…

a. The reflected angle b. The first critical angle c. The second critical angle d. The probe angle

12. Which circuit in an ultrasonic flaw detector controls the voltage or charge across the X- plates in a CRT?

a. The pulse generator b. The sweep circuit c. The receiver amplifier

d. The suppression or reject circuit

13. When scanning a surface with 0˚ probe, the distance between the consecutive scans is known as the...?

a. Gap b. Pitch c. Overlap d. All the above

14. Which of the following is the preferred sizing method used for assessing cracks? a. 6 dB Drop

b. 20 dB Drop

c. Maximum Amplitude d. All the above

15. Which type of display does an analogue flaw detector use? a. LCD

b. CRT c. VDU d. Plasma

16. What effect on beam spread does a change of probe, to one with the same frequency but larger diameter, have?

a. The half angle increases b. The half angle decreases c. a and b

d. Probe diameter does not affect beam spread

17. Which of the following materials would have the highest attenuation? a. A fine grained material

b. A coarse grained material c. A medium grained material

d. All of the above would have the same attenuation

18. At an interface, when the interface angle in the first medium is between 0˚ and the first critical angle, the refracted sound in the second medium will be…

a. A compression wave b. Shear waves

c. Surface waves d. a and b

19. The control on the flaw detector which controls the voltage or charge on the Y-plates is called the….

a. Range control b. Delay control

c. Gain or attenuator control d. Focus control

20. Which of the following sizing methods may be used with 0˚ probe? a. 6 dB drop

b. Equalisation

c. Maximum amplitude d. All of the above

21. Which of the following is a sizing methods used for assessing porosity? a. 6 dB drop

b. Equalisation

c. Maximum amplitude d. All of the above

22. Which of the following would accurately describe sound? a. Audible mechanical vibrations

b. Ultrasonic mechanical vibrations c. Infrasonic mechanical vibrations d. All of the above

23. What are ‘k’ factors?

a. Constants used in calculating beam spread b. Variables used in calculating beam spread c. Constants used in the near zone formula d. Variables used to calculate near zone length

24. What effect does beam spread have on sound attenuation? a. More beam spread, more attenuation

b. Less beam spread, less attenuation c. Less beam spread, more attenuation d. a and b

25. At an interface, when the incident angle in the first medium is between the first critical angle and the second critical angle, the refracted sound in the second medium will be….

a. Compression waves b. Shear waves

c. Surface waves d. a and b

26. What is the term used to describe an amplifier which accepts a wide array of signal frequencies and is good for defect interpretation but less sensitive at defect detection?

a. Receiver amplifier b. Broad band amplifier c. Narrow band amplifier d. Signal amplifier

27. Which of the following sizing methods does not work accurately on defects which are smaller than the ultrasonic beam?

a. 6 dB drop

b. Maximum amplitude c. DGS

d. AVG

28. Which of the following is a sizing method used for assessing length of a defect? a. 6 dB drop

b. 20 dB drop

c. Maximum amplitude d. All of the above

29. Which two properties of a material, when combined, have the most measurable effect on the sound wave velocity?

a. Grain size and surface condition b. Density and elasticity

c. Acoustic impedance and resonant frequency d. All of the above

30. Which law do we use to compare sizes of small reflectors, located in the Fraunhoffer zone, using their signal amplitudes?

a. Snell’s law b. The inverse Law

c. The inverse square Law d. b and c

31. What unit is used to quantify difference in sound intensities? a. Hz

b. mm c. dB d. m/s

32. At an interface, when the incident angle in the first medium has reached the second critical angle, the refracted sound in the second medium will be…

a. All reflected

b. Compression and shear waves c. Shear waves

d. Surface waves

33. Which of the following calibration blocks would you use to check the dead zone on a single crystal 0˚ probe?

a. Block No. 1 b. Block No. 2 c. A5

d. b or c

34. Which of the following calibration blocks may be used to calibrate the CRT to a range of 0- 100mm, when using angle probes?

a. V1, A2, IIW or Block No. 1 b. V2, A4 or Block No. 2 c. A5 or IOW Block d. a or b

35. Which scanning system shows time or distance on the horizontal axis and amplitude on the vertical axis of the display?

a. A-Scan b. B-Scan c. C-Scan

d. All of the above

36. The wavelength of ultrasound in a material may be calculated by: a. Dividing sound frequency by material velocity

b. Multiplying sound frequency by material velocity c. Dividing material velocity by sound frequency d. Multiplying material velocity by sound frequency

37. What is the difference in signal heights of two large reflectors in the far zone of the ultrasonic beam when one is twice the beam path of the other? (Assume large to be larger than the width of the ultrasonic beam)

a. 2dB b. 4dB c. 6dB d. 12dB

38. What is the difference in dBs, between a signal at 100% screen height and one at 25% screen height on the CRT?

a. 20dB b. 14dB c. 12dB d. 6dB

39. At an interface, when the angle in the first medium has exceeded the second critical angle, the refracted sound in the second medium will be..

a. All reflected

b. Compression and shear waves c. Shear waves

d. Surface waves

40. Which calibration block could you use to check probe angles? a. A2

b. A5 c. V2

d. Any of the above

41. Which of the following methods could be used to set test sensitivity when scanning with angle probes?

a. Grass

b. Reference reflectors c. DAC Curves

42. Which scanning system shows a cross-sectional view of a test piece on the display? a. A-Scan

b. B-Scan c. C-Scan

d. All of the above

43. Calculate the wavelength of sound waves in steel when using a 5MHz compression probe (Steel velocity is 5960)

a. 0.84mm b. 0.00084mm c. 1.192m d. 1.192mm

44. What is the relationship between damping, pulse length & resolution? a. Damping controls pulse length

b. Pulse length controls resolution c. Damping controls resolution d. All of the above

45. What would be the ratio of signal heights of two signals with a difference of 14dB between then?

a. 14:1 b. 20:1 c. 5:1 d. 2:1

46. What is the first critical angle for a perspex to steel interface? a. 27.4˚

b. 35 ˚ c. 57.7 ˚ d. 80 ˚

47. What is the thickness of the perspex insert in the IOW block? a. 23mm

b. 25mm c. 50mm

d. None of the above

48. How could you increase the sensitivity of an angle probe inspection? a. Use a smaller reference reflector to plot the DAC Curve

b. Lower the gain setting c. Add reject or suppression d. Any of the above

49. Which scanning system shows a plan view of a test piece, on a printout rather than a display?

a. A-Scan b. B-Scan c. C-Scan

d. All of the above

50. A material velocity of 5000m/s and a probe frequency of 2.5MHz will produce a wavelength of 2mm. What happens when we change the probe for a 5MHz one?

a. The velocity remains the same and the wavelength halves b. The velocity remains the same and the wavelength doubles c. The velocity halves and the wavelength remains the same d. The velocity doubles and the wavelength remains the same 51. What is PRF?

a. Pulse rate frequency b. Probe rate frequency c. Probe repetition frequency d. Pulse repetition frequency

52. The piezo electric effect can perform which one of the following? a. Convert electrical energy into mechanical energy

b. Convert electrical energy into signals c. Convert sound to mechanical energy d. All of the above

53. What is the second critical angle for a perspex to steel interface? a. 27.4˚

b. 35 ˚ c. 57.7 ˚ d. 80 ˚

54. What is the thickness of the V2 calibration block? a. 12.5mm

b. 20mm c. 25mm

d. Any of the above

55. Which scanning pattern requires an angle probe to be manipulated through a small arc whilst maintaining the sound focused on a fixed reflector?

a. Orbital b. Swivel c. Lateral d. Depth

a. Portability and less set-up time

b. High persistence screen allows a permanent record to be made c. Printout provides an instant permanent record

d. More skill required to set-up

57. Which of the following best describes what we term ‘infrasound’? a. Sound waves with a frequency above 20KHz

b. Sound waves with a frequency below 16KHz c. Sound waves with a frequency above 20Hz d. Sound waves with a frequency below 16Hz

58. What happens if an excessive PRF is set on the flaw detector? a. The equipment overheats

b. Ghost echoes appear on the CRT c. The piezo electric effect is lost d. Grass appears on the CRT

59. Crystals used in ultrasonic testing, which produce the correct mode of vibration, are.. a. X Cut

b. Y Cut c. Square d. Round

60. What is the practical range of shear wave probe angles for use on steel? a. 29˚ to 56˚

b. 35˚ to 80˚ c. 29˚ to 80˚ d. 35˚ to 56˚

61. What is an alternative name for the A4 calibration block? a. Dutch block

b. Sultzer block c. Kidney block d. Road block

62. Which scanning pattern requires an angle probe to be moved sideways along a fixed line? a. Orbital

b. Swivel c. Lateral d. Depth

63. What are the advantages of B-Scan systems? a. Portability and less set-up time

c. Printout provides an instant permanent record d. More skill required to set-up

64. What range of sound wave frequencies does ultrasound exist in? a. All above 20KHz

b. Above 20Hz and below 16KHz c. Above 16Hz and below 20KHz d. All below 16Hz

65. What is meant by transit time?

a. The time taken, for a pulse of energy, from leaving the probe to travel though a material and return

b. The time between pulses of energy leaving the probe

c. The time between pulses of energy returning to probe and the signal appearing on the CRT

d. The time taken for the piezo electric conversion of mechanical vibrations to electrical signals

66. Which of the following formulae determines the fundamental frequency of a piezo electric crystal?

a. Ff = t 2V b. F = λx V c. Ff = V 2t d. F = t x V

67. A probe which transmits sound into a material at 90˚ to the test surface is known as a… a. 90˚

b. Surface wave probe c. Normal probe

d. a and b

68. What is the tolerance on dimensions of calibration blocks? a. ± 1mm

b. ± 0.1mm c. ± 0.2mm

d. There is no tolerance on calibration block dimensions

69. Which scanning pattern requires an angle probe to be rotated on the spot? a. Orbital

b. Swivel c. Lateral d. Depth

a. Portability and less set-up time

b. High persistence screen allows a permanent record to be made c. Printout provides an instant permanent record

d. More skill required to set-up

71. What are the range of frequencies of sound that the human ear can detect? a. 16KHz to 20KHz

b. 16Hz to 20Hz c. 16Hz to 20KHz d. 16KHz to 20Hz

72. What is the clock interval?

a. The time taken, for a pulse of energy, from leaving the probe to travel though a material and return

b. The time between pulses of energy leaving the probe

c. The time between pulses of energy returning to probe and the signal appearing on the CRT

d. The time taken for the piezo electric conversion of mechanical vibrations to electrical signals

73. Which piezo electric crystal is the best transmitter of ultrasound? a. Quartz

b. Lithium Sulphate

c. Lead Zirconate Titanate d. Barium Titanate

74. Which probe would not have a dead zone? a. A compression probe

b. A combined double probe c. An angle probe

d. A soft nose probe

75. What is the tolerance on the amplifier accuracy check described in BS EN 12668: Part 3: 2000: clause 3.2.2.4?

a. ± 20 dB b. ± 6 dB c. ± 2 dB d. ± 1 dB

76. Which scanning pattern requires that an angle probe is moved back and forth in the direction of the beam and perpendicular to the major axis of a defect?

a. Orbital b. Swivel c. Lateral d. Depth

77. What are the disadvantages of an A-Scan system? a. Less portability and more set-up time

b. Low persistence screen allows a permanent record to be made c. No indication of defect depth or orientation

d. More skill required to interpret signal

78. In which probe would you find an acoustic barrier? a. A compression probe

b. A combined double probe c. An angle probe

d. A soft nose probe

79. What is the tolerance on the timebase linearity of a flaw detector, according to BS EN 12668: Part 3: 2000?

a. ± 1% of the whole timebase

b. ± 1% of each large division on the timebase c. ± 2% of the whole timebase

d. ± 2% of each large division on the timebase

80. What does the horizontal base line or x-axis on the flaw detector display represent? a. Time taken for the sound wave to travel through the material

b. The distance travelled by the sound wave

c. The amplitude of sound energy returning to the probe d. a and b

81. What is an alternative term used to describe longitudinal waves? a. Compression waves

b. Shear waves c. Surface waves d. Plate waves

82. Which piezo electric crystal is the best receiver of ultrasound? a. Quartz

b. Lithium Sulphate

c. Lead Zirconate Titanate d. Barium Titanate

83. Which of the following are not scanning patterns? a. Root scan

b. Transverse scan c. Depth scan d. a and b

84. What are the disadvantages of a C-Scan system? a. Less portability and more set-up time

b. Low persistence screen allows a permanent record to be made c. No indication of defect depth or orientation

d. More skill required to interpret signal

85. Which probe would be best for use on a rough surface? a. A compression probe

b. A combined double probe c. An angle probe

d. A soft nose probe

86. Which of the following is true?

a. The higher the signal noise ratio the less noise on the screen b. The lower the signal noise ration the less noise on the screen c. The signal noise ratio does not affect the clarity of the screen d. The signal noise ratio is the same on all flaw detectors

87. What is another name for the Dead Zone? a. Fresnel one

b. Fraunhoffer Zone c. Damping

d. Ringing Time

88. What is an alternative name used to describe transversal waves? a. Compression wave

b. Shear wave c. Surface wave d. Plate wave

89. What are the advantages and limitations of modern ceramic crystal materials? a. Good wear resistance but poor piezo electric properties

b. Good receivers of ultrasound but soluble in water

c. Good generators of ultrasound but low mechanical strength d. All of the above

90. What is the formula for calculating the depth of a defect when the angle of probe (β) and sound beam path length (bp) are known?

a. bp Cos β b. bp x Cos β c. bp x Sin β d. bp Sin β

91. What term is used to describe a system that sends out pulses of ultrasound then listens out for returning echoes?

a. Pulse echo

b. Through Transmission c. Tandem

d. Immersion

92. Which transducer uses a low frequency magnetic field to generate ultrasonic vibrations? a. Soft nosed probe

b. Wheel type probe c. Delay line probe d. Magnetostrictive coil

93. What is the thickness of the A2 calibration block? a. 12.5mm

b. 20mm c. 25mm d. 50mm

94. What is another name for the Near Zone? a. Fresnel Zone

b. Fraunhoffer Zone c. Damping

d. Ringing time

95. What is an alternative term used to describe Rayleigh waves? a. Compression waves

b. Shear waves c. Surface waves d. Plate waves

96. What is the law of reflection?

a. The angle of incidence = the angle of reflection b. The angle of refraction = the angle of reflection c. The angle of incidence = the angle of refraction d. Sin α Sin β = V1 V2 

97. What is the ratio of beam path to depth with a 60˚ probe? a. 1.414 : 1

b. 2 : 1 c. 2.9 : 1

d. None of the above

98. Which of the following techniques uses two probes on opposite sides of the test piece? a. Pulse echo

b. Through transmission c. Tandem

d. Immersion

99. What do we mean by the “Bandwidth” of a probe? a. The probe’s diameter

b. The centre operating frequency of the probe

c. The range of frequencies of sound the probe transmits d. The range of voltages that the probe will operate at

100. If the smallest range an analogue A-Scan flaw detector can be calibrated to is 0 – 10mm then what is the best accuracy that can be read on the CRT?

a. 0.5mm b. 0.4mm c. 0.2mm d. 0.1mm

101. What is another name for the Far Zone? a. The Fresnel zone

b. The Fraunhoffer zone c. Damping

d. Ringing time

102. What is an alternative term used to describe Lamb waves? a. Compression waves

b. Shear waves c. Surface waves d. Plate waves

103. What is Snell’s Law?

a. The angle of incidence = the angle of reflection b. The angle of refraction = the angle of reflection c. The angle of incidence = the angle of refraction d. Sin α Sin β = V1 V2 

104. What is the ratio of beam path to depth with a 45˚ probe? a. 1.414 : 1

b. 2 : 1 c. 2.9 : 1

d. None of the above

105. Which of the following techniques uses two probes, both on same surface of the test piece?

a. Pulse echo

b. Through transmission c. Tandem

106. What are the advantages of the pulse echo technique? a. Defects perpendicular to the surface may be located easily b. Probe frequencies up to 25MHz may be used

c. Thicker or highly attenuative materials may be tested as the sound only has to travel one way through the material

d. Defects can be located with great accuracy and access to only one surface is required 107. Which waves can propagate in any medium?

a. Compression waves b. Shear waves

c. Surface waves d. Plate waves

108. When thickness checking, using the multiple back wall echo method, the 8th repeat signal

from the test piece is on 60mm on the graticule. The CRT is calibrated 0 to 100mm range, what is the actual thickness of the test piece?

a. 60mm b. 48mm c. 7.5mm d. 6.0mm

109. What is the ratio of beam path to depth with a 70˚ probe? a. 1.414 : 1

b. 2 : 1 c. 2.9 : 1

d. None of the above

110. How would you determine the angle of beam produced in a different material, by a probe that produces a 45˚ angle in steel?

a. Use a block of the test material containing reference reflectors at known depths, to plot the beam angle

b. Calculate the angle using Snell’s Law c. a and b would both be used together d. either a or b could be used

111. What effect does probe frequency have on crystal ringing time? a. Higher frequency = shorter ring time

b. Higher frequency = longer ring time c. a and b

d. Frequency does not affect ringing time

In document Ultrasonic Testing - Training Notes (Page 59-80)

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