McqMate
Chapters
| 1. |
Most commercial ultrasonic testing is performed at frequencies between: |
| A. | 1 MHz and 10 MHz |
| B. | 1 MHz and 100 MHz |
| C. | 10 MHz and 50 MHz |
| D. | 1 MHz and 25 MHz |
| Answer» D. 1 MHz and 25 MHz | |
| 2. |
For a transducer with any given Q, resolution increases with: |
| A. | Sensitivity |
| B. | Frequency |
| C. | Wavelength |
| D. | Crystal thickness |
| Answer» B. Frequency | |
| 3. |
Resolving power of a transducer is directly proportional to its: |
| A. | Wavelength |
| B. | Crystal thickness |
| C. | Bandwidth |
| D. | Q |
| Answer» C. Bandwidth | |
| 4. |
The term is used to refer to the product of wave velocity and density is: |
| A. | Acoustic impedance |
| B. | The velocity-density ratio |
| C. | Index of refraction |
| D. | Reflection co-efficient |
| Answer» A. Acoustic impedance | |
| 5. |
Snell's law is given by which of the following: |
| A. | (Sin A)/(Sin B) = VB/VA |
| B. | (Sin A)/(Sin B) = VA/VB |
| C. | (Sin A)/ VB = V(Sin B)/VA |
| D. | (Sin A)[VA] = (Sin B)[ VB] |
| Answer» B. (Sin A)/(Sin B) = VA/VB | |
| 6. |
Snell's law is used to calculate: |
| A. | Angle of beam divergence |
| B. | Angle of diffraction |
| C. | Angle of refraction |
| D. | None of the above |
| Answer» C. Angle of refraction | |
| 7. |
Calculate the refracted shear wave angle in steel [VS = 0.323cm/microsec] for an incident longitudinal wave of 37.9 degrees in Plexiglas [VL = 0.267cm/microsec] |
| A. | 26 degrees |
| B. | 45 degrees |
| C. | 48 degrees |
| D. | 64 degrees |
| Answer» B. 45 degrees | |
| 8. |
Calculate the refracted shear wave angle in steel [VS = 0.323cm/microsec] for an incident longitudinal wave of 45.7 degrees in Plexiglas [VL = 0.267cm/microsec] |
| A. | 64 degrees |
| B. | 45.7 degrees |
| C. | 60 degrees |
| D. | 70 degrees |
| Answer» C. 60 degrees | |
| 9. |
Calculate the refracted shear wave angle in aluminium [VS = 0.31cm/microsec] for an incident longitudinal wave of 43.5 degrees in Plexiglas [VL =0.267cm/microsec] |
| A. | 53 degrees |
| B. | 61 degrees |
| C. | 42 degrees |
| D. | 68 degrees |
| Answer» A. 53 degrees | |
| 10. |
Calculate the refracted shear wave angle in aluminium [VS = 0.31cm/microsec] for an incident longitudinal wave of 53 degrees in Plexiglas [VL = 0.267cm/microsec] |
| A. | 53 degrees |
| B. | 61 degrees |
| C. | 42 degrees |
| D. | 68 degrees |
| Answer» D. 68 degrees | |
| 11. |
Lithium sulphate, barium titanate and lead metaniobate are examples of: |
| A. | Magnetostrictive elements |
| B. | Piezoelectric elements |
| C. | Rochelle salts |
| D. | Y cut crystals |
| Answer» B. Piezoelectric elements | |
| 12. |
The particle motion for compression waves is: |
| A. | Parallel to wave propagation |
| B. | Transverse to wave propagation |
| C. | Elliptical |
| D. | Circular |
| Answer» A. Parallel to wave propagation | |
| 13. |
Shear waves for ultrasonic testing are usually produced: |
| A. | X cut crystals |
| B. | Y cut crystals |
| C. | Modulated R-F conversion |
| D. | Mode converted longitudinal waves |
| Answer» B. Y cut crystals | |
| 14. |
Near surface resolution can be improved by: |
| A. | Using a narrow band transducer |
| B. | Using a focused transducer |
| C. | Using a high Q transducer |
| D. | None of the above |
| Answer» B. Using a focused transducer | |
| 15. |
The most important requirement for paintbrush transducer is: |
| A. | Uniform beam intensity across the transducer |
| B. | A pinpoint focal spot |
| C. | Good horizontal linearity characteristics |
| D. | Prescribed vertical and horizontal linearity characteristics |
| Answer» A. Uniform beam intensity across the transducer | |
| 16. |
Which of the following is an advantage of a focused transducer? |
| A. | Extended useful range |
| B. | Reduced sensitivity in localised area |
| C. | Improved signal to noise ratio over an extended range |
| D. | Higher resolution over a limited range |
| Answer» D. Higher resolution over a limited range | |
| 17. |
Which of the following is intended to be a ‘first cut’ or rough inspection device to be followed by more precise evaluation of any discontinuities found? |
| A. | Wheel transducer |
| B. | Focused transducer |
| C. | Paintbrush transducer |
| D. | Ball transducer |
| Answer» C. Paintbrush transducer | |
| 18. |
A wider entry surface indication or pulse may result from: |
| A. | Side lobes of the sound beam being reflected from a rough surface |
| B. | Using a lower energy pulser |
| C. | Using a higher amplifier attenuation setting |
| D. | Huygen's principle |
| Answer» A. Side lobes of the sound beam being reflected from a rough surface | |
| 19. |
Which of the following methods might be used to reduce attenuation losses in an ultrasonic test? |
| A. | Use a shorter wavelength |
| B. | Use a lower frequency transducer |
| C. | Change from longitudinal waves to shear waves |
| D. | Change to a coarser grained test piece |
| Answer» B. Use a lower frequency transducer | |
| 20. |
When comparing discontinuity echoes to equivalent flat bottom hole echoes in materials with similar impedance, surface finish and attenuation: |
| A. | The flaw is never larger than the flat bottom hole |
| B. | The flaw is never smaller than the flat bottom hole |
| C. | The flaw is always smaller than the flat bottom hole |
| D. | None of the above |
| Answer» D. None of the above | |
| 21. |
An advantage of immersion testing is that: |
| A. | Large parts are easily inspected |
| B. | Most test systems are easily transported in the field |
| C. | High test frequencies may be used |
| D. | Most test systems are not easily transported in the field |
| Answer» C. High test frequencies may be used | |
| 22. |
An advantage of immersion testing is that: |
| A. | Large parts may be easily inspected |
| B. | Most test systems are easily transported in the field |
| C. | Low test frequencies may be used |
| D. | Irregularly shaped test pieces can be virtually completely examined |
| Answer» D. Irregularly shaped test pieces can be virtually completely examined | |
| 23. |
An ultrasonic data display which shows a plan view presentation of the data is called: |
| A. | A scan |
| B. | B scan |
| C. | C scan |
| D. | Orthogonal view |
| Answer» C. C scan | |
| 24. |
An ultrasonic display which shows a cross section of the test piece and any flaws which are found are called: |
| A. | A scan |
| B. | B scan |
| C. | C scan |
| D. | Orthogonal view |
| Answer» B. B scan | |
| 25. |
An ultrasonic display which shows echo locations and amplitude is called: |
| A. | A scan |
| B. | B scan |
| C. | C scan |
| D. | Orthogonal view |
| Answer» A. A scan | |
| 26. |
An advantage of using lower frequencies during ultrasonic testing is that: |
| A. | Near surface resolution is improved |
| B. | Sensitivity to small discontinuities is improved |
| C. | Beam spread is reduced |
| D. | Sensitivity to unfavourable oriented flaws is improved |
| Answer» D. Sensitivity to unfavourable oriented flaws is improved | |
| 27. |
A method of compensating for the ‘dead zone’ or near surface resolution problems is to: |
| A. | Inspect all areas of the test piece twice to assure repeatability of indications |
| B. | Re-inspect from the opposite side of the test piece if geometry permits |
| C. | Re-inspect using a higher energy pulse |
| D. | Re-inspect using a higher frequency transducer that does not have a ‘dead |
| Answer» B. Re-inspect from the opposite side of the test piece if geometry permits | |
| 28. |
When testing a test piece with parallel front and back surfaces, no back wall echo can be obtained. Which of the following actions might enable you to obtain a back wall echo? |
| A. | Use a wetter transducer |
| B. | Use a lower frequency transducer |
| C. | Use a transducer with a narrower bandwidth |
| D. | Use a higher frequency transducer |
| Answer» B. Use a lower frequency transducer | |
| 29. |
Materials which can readily be inspected with frequencies of 1 to 5 MHz are: |
| A. | Steel, cast iron and concrete |
| B. | Titanium, wood and aluminium |
| C. | Magnesium, titanium and steel |
| D. | All of the above |
| Answer» C. Magnesium, titanium and steel | |
| 30. |
When variations are noticed in the front surface reflection, the test piece should be inspected for possible near surface discontinuities by: |
| A. | Using a lower frequency transducer |
| B. | Using a higher pulse energy |
| C. | Inspecting from the opposite side |
| D. | Calibrating on a smaller diameter flat bottom hole |
| Answer» C. Inspecting from the opposite side | |
| 31. |
Forging bursts are most often orientated: |
| A. | Parallel to the surface |
| B. | Perpendicular to the surface |
| C. | In a random manner |
| D. | At an angle of 45 degrees to the surface |
| Answer» C. In a random manner | |
| 32. |
The purpose of adding a wetting agent to an immersion bath is: |
| A. | To make sure the bath is wet |
| B. | To reduce corrosive properties of the bath |
| C. | To eliminate air bubbles in the bath |
| D. | To prevent rust |
| Answer» C. To eliminate air bubbles in the bath | |
| 33. |
During immersion testing of pipe or tubing the incident longitudinal wave angle must be limited to a narrow range. The reason for the upper limit is: |
| A. | To avoid complete reflection of ultrasound from the test piece |
| B. | To prevent formation of Rayleigh waves |
| C. | To prevent formation of shear waves |
| D. | To avoid saturating the test piece with ultrasound |
| Answer» A. To avoid complete reflection of ultrasound from the test piece | |
| 34. |
A calibration for immersion ultrasonic testing of pipe or tubing should establish a transducer position such as: |
| A. | I.D. and O.D. notches produce equal responses for equivalent metal path distances |
| B. | Rayleigh waves are generated through the entire pipe or tubing wall |
| C. | All ultrasound enters the test piece |
| D. | Only longitudinal waves are generated in the test piece |
| Answer» C. All ultrasound enters the test piece | |
| 35. |
During immersion ultrasonic testing of pipe or tubing, spurious echoes may be caused by: |
| A. | Dirt on the test piece |
| B. | Grease on the test piece |
| C. | Air bubbles on the test piece |
| D. | All of the above |
| Answer» D. All of the above | |
| 36. |
Typical frequencies which might be used to perform ultrasonic testing of concrete are: |
| A. | 25 to 100 kHz |
| B. | 200 to 5 MHz |
| C. | 1 MHz to 5 MHz |
| D. | 2.25 MHz to 10 MHz |
| Answer» A. 25 to 100 kHz | |
| 37. |
Typical frequencies which might be used to perform ultrasonic testing of ferrous and non-ferrous welds are: |
| A. | 25 to 100 kHz |
| B. | 200 to 5 MHz |
| C. | 1 MHz to 5 MHz |
| D. | 2.25 MHz to 10 MHz |
| Answer» C. 1 MHz to 5 MHz | |
| 38. |
Which of the following materials would probably require testing at the lowest frequency? |
| A. | Small grained mild steel |
| B. | Mild steel castings |
| C. | Mild steel forgings |
| D. | Cast iron |
| Answer» D. Cast iron | |
| 39. |
Which of the following is an advantage of contact testing over immersion? |
| A. | Ability to maintain uniform coupling on rough surface |
| B. | Longer dead time near the front surface of the test piece |
| C. | Ease of field use |
| D. | Ability to continuously vary incident wave angle during test |
| Answer» C. Ease of field use | |
| 40. |
Which of the following is a disadvantage of contact testing? |
| A. | Ability to maintain uniform coupling on rough surface |
| B. | Ease of field use |
| C. | Greater penetrating power than immersion testing |
| D. | Less penetrating power than immersion testing |
| Answer» A. Ability to maintain uniform coupling on rough surface | |
| 41. |
A typical application for a through transmission technique is: |
| A. | Flaw depth sizing |
| B. | Flaw depth location |
| C. | Thickness gauging |
| D. | Bond/unbond testing |
| Answer» D. Bond/unbond testing | |
| 42. |
An ultrasonic technique in which two transducers are used, in a constant position relative to each other, is: |
| A. | Through transmission |
| B. | Contact testing |
| C. | Pulse echo |
| D. | Continuous wave |
| Answer» A. Through transmission | |
| 43. |
Which of the following cast materials could most likely be successfully ultrasonically tested? |
| A. | Low carbon steel |
| B. | Stainless steel |
| C. | Iron |
| D. | Pure lead |
| Answer» A. Low carbon steel | |
| 44. |
Which of the following product forms would probably be tested at the lowest frequency? |
| A. | Forgings |
| B. | Hot rolled plate |
| C. | Castings |
| D. | Extrusions |
| Answer» C. Castings | |
| 45. |
Addition of approximately 6% antimony as an alloying element could be expected to increase the ultrasonic inspectability of which of the following materials? |
| A. | Low carbon steel |
| B. | Stainless steel |
| C. | Iron |
| D. | Pure lead |
| Answer» D. Pure lead | |
| 46. |
Strong signals which travel across the horizontal time base of an A scan presentation while the transducer is motionless on the test piece are probably: |
| A. | Randomly oriented flaws |
| B. | Electrical interference |
| C. | Grain noise |
| D. | Loose wedge on transducer |
| Answer» B. Electrical interference | |
| 47. |
Excessive ringing of the transducer could be caused by: |
| A. | Electrical interference |
| B. | Loose crystal |
| C. | Test piece with large grain size |
| D. | Test piece with small grain size |
| Answer» B. Loose crystal | |
| 48. |
When inspecting a long bar with a longitudinal wave from one end, a series of additional echoes are seen immediately after the bottom surface reflection. these are most likely: |
| A. | Refracted shear and longitudinal waves caused by beam spread |
| B. | Flaw indications |
| C. | Multiples of the back surface reflection |
| D. | None of the above |
| Answer» D. None of the above | |
| 49. |
One of the most apparent characteristics of a discontinuity echo, as opposed to a nonrelevant indication is: |
| A. | Lack of repeatability |
| B. | Sharp, distinct signal |
| C. | Stable position with fixed transducer position |
| D. | High noise level |
| Answer» B. Sharp, distinct signal | |
| 50. |
Typical immersion test frequencies for wrought aluminium are: |
| A. | 10 MHz and up |
| B. | 5 MHz and below |
| C. | 500 MHz to 1 MHz |
| D. | Above 25 MHz |
| Answer» A. 10 MHz and up | |
| 51. |
Choice of ultrasonic test frequency depends upon which of the following? |
| A. | Surface condition |
| B. | Minimum size discontinuity to be detected |
| C. | Level of grain noise |
| D. | All of the above |
| Answer» D. All of the above | |
| 52. |
Polished, flat surfaces are undesirable for ultrasonic testing consideration because: |
| A. | Coupling losses are greater |
| B. | Scan speeds tend to be too rapid |
| C. | Spurious lamb waves are prevalent |
| D. | The probe sticks to the surface because of suction |
| Answer» D. The probe sticks to the surface because of suction | |
| 53. |
The most effective liquid ultrasonic couplant (highest acoustic impedance) is: |
| A. | SAE 30 motor oil |
| B. | Glycerine |
| C. | Water |
| D. | Grease |
| Answer» B. Glycerine | |
| 54. |
When using a straight beam technique to examine a thick test piece what change(s) would you expect to see in back wall echo size as you approach the side of the test piece? (Transducer remains completely on test piece) |
| A. | No change |
| B. | Increase |
| C. | Decrease |
| D. | Depends on material acoustic velocity |
| Answer» C. Decrease | |
| 55. |
What useful purpose may be served by maintaining grass on the baseline? |
| A. | To estimate casting grain size |
| B. | To provide a reference for estimating signal to noise ratio |
| C. | To verify adequate coupling to the test piece |
| D. | All of the above |
| Answer» C. To verify adequate coupling to the test piece | |
| 56. |
Which of the following describes the sound field propagating in a piece of steel bar stock which is being tested from one end with longitudinal waves? |
| A. | Non uniform, containing maxima and minima because of the focusing effect of laterally reflected waves |
| B. | Increasing to a peak, then decreasing throughout the far field |
| C. | Uniformly decreasing along the length of the bar |
| D. | Decreasing according to the inverse square law |
| Answer» D. Decreasing according to the inverse square law | |
| 57. |
When a probe is coupled to a solid, strong surface waves may be produced: |
| A. | If a high frequency probe is used |
| B. | If the probe has only incomplete contact with the surface |
| C. | If the probe is large in diameter |
| D. | None of the above |
| Answer» D. None of the above | |
| 58. |
To avoid interfering surface waves, low frequencies should only be used on: |
| A. | Polished surfaces |
| B. | Castings |
| C. | Flat surfaces |
| D. | Non-polished surfaces |
| Answer» B. Castings | |
| 59. |
Which of the following conditions would be most likely to cause strong, interfering surface waves? |
| A. | High frequency transducers |
| B. | Testing on a small diameter surface |
| C. | Testing on a flat surface |
| D. | Testing on a curved surface with a contoured wedge and transducer |
| Answer» D. Testing on a curved surface with a contoured wedge and transducer | |
| 60. |
Flaw sizing by the 6 dB drop technique is applicable to: |
| A. | Large flaws relative to the sound beam |
| B. | Small flaws relative to the sound beam |
| C. | Any flaws |
| D. | None of the above |
| Answer» A. Large flaws relative to the sound beam | |
| 61. |
How many decibels of attenuation correspond to an ultrasonic signal loss of from 100% to 25% on full screen height? |
| A. | 6 |
| B. | 10 |
| C. | 12 |
| D. | 14 |
| Answer» C. 12 | |
| 62. |
An increase in gain of how many decibels corresponds to a 5:1 increase in flaw echo amplitude? |
| A. | 10 |
| B. | 14 |
| C. | 6 |
| D. | 20 |
| Answer» B. 14 | |
| 63. |
A focused sound beam is produced by a: |
| A. | Convex mirror |
| B. | Concave transducer |
| C. | Convex lens |
| D. | None of the above |
| Answer» B. Concave transducer | |
| 64. |
A divergent sound beam is produced by: |
| A. | Concave mirror |
| B. | Convex mirror |
| C. | Convex lens |
| D. | None of the above |
| Answer» C. Convex lens | |
| 65. |
A type of cast iron which has ultrasonic properties similar to steel is: |
| A. | White |
| B. | Gray |
| C. | Lamellar |
| D. | Ductile |
| Answer» A. White | |
| 66. |
What effect does hardening have on acoustic velocity in steel? |
| A. | Increases |
| B. | Decreases |
| C. | No effect |
| D. | Any of the above |
| Answer» C. No effect | |
| 67. |
Variation in acoustic velocity from one type of steel to another is usually less than: |
| A. | 1% |
| B. | 2% |
| C. | 5% |
| D. | 10% |
| Answer» A. 1% | |
| 68. |
In general, which of the following materials would have the least ultrasonic attenuation? |
| A. | Aluminium |
| B. | Silver |
| C. | Lead |
| D. | Tungsten |
| Answer» A. Aluminium | |
| 69. |
The velocity of lamb waves depends on: |
| A. | Elastic constants of test material |
| B. | Plate thickness |
| C. | Frequency |
| D. | All of the above |
| Answer» D. All of the above | |
| 70. |
Which of the following is the most durable piezoelectric material? |
| A. | Barium titanate |
| B. | Quartz |
| C. | Dipotassoium tartrate |
| D. | Rochelle salt |
| Answer» B. Quartz | |
| 71. |
Which of the following methods are used to produce ultrasonic waves? |
| A. | Magnetostrictive methods |
| B. | Magnetoinductive methods |
| C. | Piezoelectric elements |
| D. | All of the above |
| Answer» D. All of the above | |
| 72. |
Spurious indications may be caused by which of the following? |
| A. | Test piece edges |
| B. | Mode conversions |
| C. | Multiple reflections from a single interface |
| D. | All of the above |
| Answer» D. All of the above | |
| 73. |
A reason for using a dual element search unit is: |
| A. | Improving near surface resolution |
| B. | Improving penetration |
| C. | Eliminating wear on the crystal faces |
| D. | None of the above |
| Answer» A. Improving near surface resolution | |
| 74. |
A wheel transducer is normally considered: |
| A. | A contact method |
| B. | A dynamic scanning method |
| C. | An immersion method |
| D. | A static scanning method |
| Answer» C. An immersion method | |
| 75. |
Which of the following is not an advantage of a focused transducer? |
| A. | High sensitivity to small flaws |
| B. | Deep penetration |
| C. | High resolving power |
| D. | Not much affected by surface roughness |
| Answer» B. Deep penetration | |
| 76. |
What type of search unit allows the greatest resolving power with standard ultrasonic testing equipment? |
| A. | Delay tip |
| B. | Focused |
| C. | Highly damped |
| D. | High Q |
| Answer» B. Focused | |
| 77. |
The 50 mm diameter hole in an IIW block is used to: |
| A. | Determine the beam index point |
| B. | Check resolution |
| C. | Calibrate angle beam distance |
| D. | Check beam angle |
| Answer» D. Check beam angle | |
| 78. |
The 100 mm radius in an IIW block is used to: |
| A. | Calibrate sensitivity level |
| B. | Check resolution |
| C. | Calibrate angle beam distance |
| D. | Check beam angle |
| Answer» C. Calibrate angle beam distance | |
| 79. |
Which of the following is a disadvantage of immersion test units? |
| A. | Inspection speed |
| B. | Ease of controlling sound beam direction |
| C. | Portability |
| D. | Application to automatic scanning techniques |
| Answer» C. Portability | |
| 80. |
Acoustic energy propagates in different modes. Which of the following represent a mode? |
| A. | Longitudinal wave |
| B. | Shear wave |
| C. | Surface wave |
| D. | All of the above |
| Answer» D. All of the above | |
| 81. |
Which of the following would be considered application(s) of ultrasonic testing? |
| A. | Determination of a material’s elastic modulus |
| B. | Study of a material’s metallurgical structure |
| C. | Measurement of a material’s thickness |
| D. | All of the above |
| Answer» D. All of the above | |
| 82. |
Waves whose particle displacement is parallel to the direction of propagation are called: |
| A. | Longitudinal waves |
| B. | Shear waves |
| C. | Lamb waves |
| D. | Rayleigh waves |
| Answer» A. Longitudinal waves | |
| 83. |
The only sound waves which travel in liquids are: |
| A. | Longitudinal waves |
| B. | Shear waves |
| C. | Rayleigh waves |
| D. | Plate waves |
| Answer» A. Longitudinal waves | |
| 84. |
In steel, the velocity of sound is greatest in which of the following modes of vibration? |
| A. | Longitudinal |
| B. | Shear |
| C. | Surface wave |
| D. | Sound velocity is identical in all modes, in a given material |
| Answer» A. Longitudinal | |
| 85. |
The scattering of the rays of an ultrasonic beam due to reflection from a highly irregular surface is called: |
| A. | Angulation |
| B. | Dispersion |
| C. | Refraction |
| D. | Diffraction |
| Answer» D. Diffraction | |
| 86. |
Acoustic impedance is a material's: |
| A. | (Density)/(velocity) |
| B. | (Density) × (velocity) |
| C. | Refractive index |
| D. | (Density)/(refractive index) |
| Answer» B. (Density) × (velocity) | |
| 87. |
When a sound beam is incident on an acoustic interface at some angle other than normal incidence, which of the following occurs? |
| A. | Reflection |
| B. | Refraction |
| C. | Mode conversion |
| D. | All of the above |
| Answer» D. All of the above | |
| 88. |
The angle formed by an ultrasonic wave as it enters a medium of different velocity than the one from which it came and a line drawn perpendicular to the interface between the two media is called: |
| A. | The angle of incidence |
| B. | The angle of refraction |
| C. | The angle of diffraction |
| D. | The angle of reflection |
| Answer» B. The angle of refraction | |
| 89. |
Which of the following frequencies would probably result in the greatest ultrasonic attenuation losses? |
| A. | 1 MHz |
| B. | 2.25 MHz |
| C. | 10 MHz |
| D. | 25 MHz |
| Answer» D. 25 MHz | |
| 90. |
Attenuation is made up of: |
| A. | Diffusion and absorption |
| B. | Scatter and reflection |
| C. | Absorption and scatter |
| D. | Reflection at grain boundaries |
| Answer» C. Absorption and scatter | |
| 91. |
The most important factor required for the proper interpretation of ultrasonic test results is: |
| A. | The ultrasonic signal amplitude |
| B. | A knowledge of the test specimen material and its construction |
| C. | A knowledge of the ultrasonic instruments operating characteristics |
| D. | The ultrasonic signal location |
| Answer» B. A knowledge of the test specimen material and its construction | |
| 92. |
A significant limitation of a lower frequency, single element transducer is: |
| A. | Scatter of sound beam due to microstructure of test object |
| B. | Increased grain noise or ‘hash’ |
| C. | Less beam spread |
| D. | Impaired ability to display discontinuities just below the entry surface |
| Answer» D. Impaired ability to display discontinuities just below the entry surface | |
| 93. |
Which of the following is the least efficient generator of ultrasonic waves: |
| A. | Quartz |
| B. | Lithium sulphate |
| C. | Lead metaniobate |
| D. | Barium titanate |
| Answer» A. Quartz | |
| 94. |
Which of the following is the least efficient receiver of ultrasonic Energy? |
| A. | Quartz |
| B. | Lithium sulphate |
| C. | Lead metaniobate |
| D. | Barium titanate |
| Answer» D. Barium titanate | |
| 95. |
The length of the zone adjacent to a transducer in which fluctuations in sound pressure occur is mostly affected by: |
| A. | The frequency of the transducer |
| B. | The diameter of the transducer |
| C. | The length of transducer cable |
| D. | Both (a) and (b) |
| Answer» D. Both (a) and (b) | |
| 96. |
An advantage of using a transducer with a large beam spread is: |
| A. | Higher sensitivity to small discontinuities |
| B. | Less likelihood of spurious echoes |
| C. | Greater likelihood of spurious echoes |
| D. | Greater likelihood of detecting randomly oriented discontinuities |
| Answer» D. Greater likelihood of detecting randomly oriented discontinuities | |
| 97. |
Resolution is inversely proportional to: |
| A. | Wavelength |
| B. | Crystal thickness |
| C. | Bandwidth |
| D. | Mechanical losses |
| Answer» B. Crystal thickness | |
| 98. |
Of the piezoelectric materials listed below, the most efficient sound transmitter is: |
| A. | Lithium sulphate |
| B. | Quartz |
| C. | Barium titanate |
| D. | Silver oxide |
| Answer» C. Barium titanate | |
| 99. |
Other factors being equal, which of the following transducers would have the greatest beam spread? |
| A. | A larger diameter transducer |
| B. | A smaller diameter transducer |
| C. | A higher frequency transducer |
| D. | None of the above has any effect |
| Answer» B. A smaller diameter transducer | |
| 100. |
The fundamental frequency of a piezoelectric crystal is primarily a function of: |
| A. | The length of the applied voltage pulse |
| B. | The amplifying characteristics of the pulse amplifier in the instrument |
| C. | The thickness of the crystal |
| D. | None of the above |
| Answer» C. The thickness of the crystal | |
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