McqMate
Chapters
| 1. |
The divergence of an ultrasonic beam is dependant on: |
| A. | Transducer wavelength and diameter |
| B. | Test specimen density |
| C. | The sound wave's angle of incidence |
| D. | The degree of damping of the ultrasonic transducer |
| Answer» A. Transducer wavelength and diameter | |
| 2. |
When a longitudinal wave is incident upon an inclined interface between zero degrees and the first critical angle: |
| A. | The sound beam is totally reflected |
| B. | Only shear waves are produced in the second material |
| C. | Shear waves and longitudinal waves are produced in the second material |
| D. | Only longitudinal waves are produced in the second material |
| Answer» C. Shear waves and longitudinal waves are produced in the second material | |
| 3. |
The piezoelectric material in a search unit which vibrates to produce ultrasonic waves is called: |
| A. | A backing material |
| B. | A lucite wedge |
| C. | A transducer element or crystal |
| D. | A couplant |
| Answer» C. A transducer element or crystal | |
| 4. |
When a longitudinal wave is incident upon an inclined interface and is refracted at ninety degrees, the angle of the incident longitudinal wave is called: |
| A. | The Snell constant |
| B. | The Snell angle |
| C. | The mode conversion constant |
| D. | The first critical angle |
| Answer» D. The first critical angle | |
| 5. |
When a longitudinal wave sound beam passes through an acoustic interface at some angle other than zero degrees: |
| A. | Surface waves are generated |
| B. | Plate waves are generated |
| C. | Reflection, refraction and mode conversion will occur |
| D. | The first critical angle is reached |
| Answer» C. Reflection, refraction and mode conversion will occur | |
| 6. |
Which of the following can be a source of spurious ultrasonic signals? |
| A. | Surface roughness of the test piece |
| B. | Mode conversion within the test piece |
| C. | Shape or contour of the test piece |
| D. | All of the above |
| Answer» D. All of the above | |
| 7. |
A noisy base line, or hash may result in: |
| A. | Laminations in the test piece |
| B. | Discontinuities at an angle to the test piece surface |
| C. | Large grain size |
| D. | Fatigue cracks |
| Answer» C. Large grain size | |
| 8. |
Sound waves which travel on the surface of a solid in a manner similar to waves on a water surface are called: |
| A. | Rayleigh waves |
| B. | Shear waves |
| C. | Primary waves |
| D. | Compression waves |
| Answer» A. Rayleigh waves | |
| 9. |
Lamb waves are formed in a part which has: |
| A. | A thickness greater that about ten wavelengths |
| B. | A thickness approximately equal to the wavelength |
| C. | Low acoustic impedance compared to the transducer crystal material |
| D. | A thickness of about four wavelengths |
| Answer» B. A thickness approximately equal to the wavelength | |
| 10. |
Which type(s) of sound wave modes will propagate through liquids? |
| A. | Longitudinal |
| B. | Shear |
| C. | Surface |
| D. | All of the above |
| Answer» A. Longitudinal | |
| 11. |
When the motion of the particles of a medium is transverse to the direction of propagation, the wave being transmitted is called a: |
| A. | Longitudinal wave |
| B. | Shear wave |
| C. | Surface wave |
| D. | Lamb wave |
| Answer» B. Shear wave | |
| 12. |
Which of the following test frequencies would generally provide the best penetration in a 12 inch thick specimen of coarse-grained steel? |
| A. | 1.0 MHz |
| B. | 2.25 MHz |
| C. | 5.0 MHz |
| D. | 10 MHz |
| Answer» A. 1.0 MHz | |
| 13. |
An oscilloscope display in which the screen base line is adjusted to represent the one way distance in a test piece is called a: |
| A. | A scan display |
| B. | B scan display |
| C. | C scan display |
| D. | D scan display |
| Answer» B. B scan display | |
| 14. |
A common use of ultrasonic testing is: |
| A. | Cleaning |
| B. | Detecting of sub-surface indications |
| C. | Determination of the test piece ductility |
| D. | Communications |
| Answer» B. Detecting of sub-surface indications | |
| 15. |
Sound waves of a frequency beyond the hearing range of the human ear are referred to as ultrasonic waves or vibrations, and the term embraces all vibrational waves of frequency greater than approximately: |
| A. | 20 kHz |
| B. | 2 MHz |
| C. | 2 kHz |
| D. | 200 kHz |
| Answer» A. 20 kHz | |
| 16. |
Y cut crystals produce: |
| A. | Longitudinal waves |
| B. | Shear waves |
| C. | Lamb waves |
| D. | Surface waves |
| Answer» B. Shear waves | |
| 17. |
The cable that connects the ultrasonic instrument to the search unit is specially designed so that one conductor is centred inside another. The technical name for such a cable is: |
| A. | BX cable |
| B. | Conduit |
| C. | Coaxial cable |
| D. | Ultrasonic conductor cable grade 20 |
| Answer» C. Coaxial cable | |
| 18. |
As ultrasonic frequency increases: |
| A. | Wavelength increases |
| B. | Wavelength decreases |
| C. | Sound velocity increases |
| D. | Sound velocity decreases |
| Answer» B. Wavelength decreases | |
| 19. |
In an A scan presentation, the amplitude of vertical indications on the screen represents the: |
| A. | Amount of ultrasonic sound energy returning to the search unit |
| B. | Distance travelled by the search unit |
| C. | Thickness of material being tested |
| D. | Elapsed time since the ultrasonic pulse was generated |
| Answer» A. Amount of ultrasonic sound energy returning to the search unit | |
| 20. |
Loss of the test piece back wall echo during scanning may be caused by: |
| A. | An abnormally homogeneous material structure |
| B. | A smooth entry surface on the test piece |
| C. | A discontinuity which is not parallel to the entry surface |
| D. | An opposite surface which is parallel to the entry surface |
| Answer» C. A discontinuity which is not parallel to the entry surface | |
| 21. |
When a sound beam is reflected: |
| A. | The angle of reflection is found using Snell's law |
| B. | The angle of reflection equals the angle of incidence |
| C. | All the sound energy is reflected unless the acoustic impedance is zero |
| D. | Beam spread is decreased |
| Answer» B. The angle of reflection equals the angle of incidence | |
| 22. |
Which of the following circuits converts electrical energy to ultrasonic energy? |
| A. | The pulse generator |
| B. | The transducer |
| C. | The transformer |
| D. | The power supply |
| Answer» B. The transducer | |
| 23. |
An instrument display in which the horizontal base line represents elapsed time and the vertical deflection represents signal amplitudes is called: |
| A. | A scan |
| B. | B scan |
| C. | C scan |
| D. | A time line display |
| Answer» A. A scan | |
| 24. |
Which of the following circuits provides short duration, high energy pulses which are used to excite the transducer? |
| A. | The pulse generator |
| B. | The amplifier |
| C. | The transducer |
| D. | The clock |
| Answer» A. The pulse generator | |
| 25. |
A cross section view of a test piece is produced by which of the following? |
| A. | A scan |
| B. | B scan |
| C. | C scan |
| D. | A time line display |
| Answer» B. B scan | |
| 26. |
Echo amplitude losses may be caused by: |
| A. | Entry surface roughness |
| B. | Coarse grain size |
| C. | Discontinuity orientation |
| D. | All of the above |
| Answer» D. All of the above | |
| 27. |
Which of the following is an advantage of using a focused transducer? |
| A. | The useful range of the transducer is decreased |
| B. | The useful range of the transducer is increased |
| C. | Sensitivity to the effects of a rough surface is increased |
| D. | Greater sensitivity is achieved in the transducer's useable range |
| Answer» D. Greater sensitivity is achieved in the transducer's useable range | |
| 28. |
Which of the following circuits provide current to operate the ultrasonic instrument? |
| A. | The pulse generator |
| B. | The amplifier |
| C. | The power supply |
| D. | The sweep generator |
| Answer» C. The power supply | |
| 29. |
Which of the following is a true statement? |
| A. | Higher frequencies produce lower sensitivity |
| B. | Higher frequencies produce longer wavelengths |
| C. | Thicker crystals produce lower frequency transducers |
| D. | Longer wavelengths produce higher sensitivity |
| Answer» C. Thicker crystals produce lower frequency transducers | |
| 30. |
Which type(s) of sound wave modes will propagate through solids? |
| A. | Longitudinal |
| B. | Shear |
| C. | Surface |
| D. | All of the above |
| Answer» D. All of the above | |
| 31. |
The longitudinal wave incident angle at which the refracted shear wave angle equals ninety degrees is called: |
| A. | The Snell angle |
| B. | The Snell constant |
| C. | The first critical angle |
| D. | The second critical angle |
| Answer» D. The second critical angle | |
| 32. |
The amount of beam divergence from a crystal is primarily dependent on the: |
| A. | Type of test |
| B. | Tightness of crystal backing in the search unit |
| C. | Frequency and crystal size |
| D. | Pulse length |
| Answer» C. Frequency and crystal size | |
| 33. |
In ultrasonic testing, a liquid coupling medium between the crystal surface and the part surface is necessary because : |
| A. | Lubricant is required to minimize wear on the crystal surface |
| B. | An air interface between the crystal surface and the part surface would almost completely reflect the ultrasonic vibrations |
| C. | The crystal will not vibrate if placed directly in contact with the surface of the part being inspected |
| D. | The liquid is necessary to complete the electrical circuit in the search unit |
| Answer» B. An air interface between the crystal surface and the part surface would almost completely reflect the ultrasonic vibrations | |
| 34. |
X cut crystals produce: |
| A. | Longitudinal waves |
| B. | Shear waves |
| C. | Lamb waves |
| D. | Surface waves |
| Answer» A. Longitudinal waves | |
| 35. |
Lower frequency transducers are normally used: |
| A. | In contact testing applications |
| B. | In angle beam testing applications |
| C. | In immersion testing applications |
| D. | Where deeper penetration is required |
| Answer» D. Where deeper penetration is required | |
| 36. |
All other factors being equal, which of the following modes of vibration has the greatest velocity? |
| A. | Shear wave |
| B. | Transverse wave |
| C. | Surface wave |
| D. | Longitudinal wave |
| Answer» D. Longitudinal wave | |
| 37. |
In immersion testing, the position of the search unit is often varied to transmit sound into the test part at various angles to the front surface. Such a procedure is referred to as: |
| A. | Angulation |
| B. | Dispersion |
| C. | Reflection testing |
| D. | Refraction |
| Answer» A. Angulation | |
| 38. |
The angle of a refracted shear wave generated as a sound wave passes at an angle through an acoustic interface is dependant on: |
| A. | The acoustic impedances of the materials of each side of the interface |
| B. | The frequency of the incident sound wave |
| C. | The wavelength of the incident sound wave |
| D. | The hardness of the materials on each side of the interface |
| Answer» A. The acoustic impedances of the materials of each side of the interface | |
| 39. |
Which of the following is a likely effect of a rough test piece surface? |
| A. | An improved ultrasonic signal to noise ratio |
| B. | A more penetrating sound beam |
| C. | Loss of discontinuity signal amplitude |
| D. | Higher test reliability |
| Answer» C. Loss of discontinuity signal amplitude | |
| 40. |
Wavelength is: |
| A. | The distance from the crest to the next trough of a sound wave |
| B. | The time required for a sound wave to propagate from a trough to the next trough of a sound wave |
| C. | The distance a sound wave travels in one second |
| D. | The distance from trough to trough or from peak to peak of a sound wave |
| Answer» D. The distance from trough to trough or from peak to peak of a sound wave | |
| 41. |
The velocity of surface waves is approximately shear waves in the same material. |
| A. | Two times |
| B. | Four times |
| C. | One half |
| D. | Nine-tenths |
| Answer» D. Nine-tenths | |
| 42. |
An ultrasonic instrument control which allows moving an A scan display to the left or right without changing the distance between any echoes displayed is called: |
| A. | The sweep length or range control |
| B. | The damping control |
| C. | The sweep delay |
| D. | The pulse length control |
| Answer» C. The sweep delay | |
| 43. |
A disadvantage of using natural quartz crystals in a search unit is that: |
| A. | It will dissolve in water |
| B. | It is the least effective generator of ultrasonic energy of all commonly used materials |
| C. | It easily loses it operating characteristics as it ages |
| D. | None of the above is correct |
| Answer» B. It is the least effective generator of ultrasonic energy of all commonly used materials | |
| 44. |
The formula Sin A/Sin B = VA/VB is known as: |
| A. | The Fresnell relationship |
| B. | Snell's law |
| C. | The law of sines |
| D. | The critical velocity ratio |
| Answer» B. Snell's law | |
| 45. |
A 25 MHz search unit would most likely be used during: |
| A. | Straight beam contact testing |
| B. | Immersion testing |
| C. | Angle beam contact testing |
| D. | Surface wave contact testing |
| Answer» B. Immersion testing | |
| 46. |
A technique in which two transducers are used, one on each side of the test piece, is called: |
| A. | Angle beam testing |
| B. | Modified immersion testing |
| C. | Through transmission testing |
| D. | Twinning |
| Answer» C. Through transmission testing | |
| 47. |
Sound beam intensity is irregular in the area called: |
| A. | The near field |
| B. | The far field |
| C. | The beam spread |
| D. | The delay line |
| Answer» A. The near field | |
| 48. |
A more highly damped transducer crystal results in: |
| A. | Better resolution |
| B. | Better sensitivity |
| C. | Lower sensitivity |
| D. | Poorer resolution |
| Answer» A. Better resolution | |
| 49. |
The process of comparing an instrument or device with a standard is called: |
| A. | Angulation |
| B. | Calibration |
| C. | Attenuation |
| D. | Correlation |
| Answer» B. Calibration | |
| 50. |
Scattering of an ultrasonic beam is most pronounced when: |
| A. | Material grain size and wavelength are comparable |
| B. | Low frequency transducers are used |
| C. | Large wavelengths are used for ultrasonic testing |
| D. | None of the above |
| Answer» A. Material grain size and wavelength are comparable | |
| 51. |
Ultrasonic testing is: |
| A. | Mechanical energy with a speed of propagation faster than the speed of sound |
| B. | Sound which has a frequency or pitch above the range of the human ear |
| C. | The science of discontinuity detection using ultrasonic sound |
| D. | Mechanical vibrations below the frequency of human hearing |
| Answer» B. Sound which has a frequency or pitch above the range of the human ear | |
| 52. |
Which technique would most likely be used to examine a weld, with the weld cap still in place? |
| A. | Through transmission testing |
| B. | Angle beam testing |
| C. | Straight beam testing |
| D. | None of the above |
| Answer» B. Angle beam testing | |
| 53. |
The maximum frequency usually used for contact testing is: |
| A. | 1 MHz |
| B. | 5 MHz |
| C. | 10 MHz |
| D. | 25 MHz |
| Answer» B. 5 MHz | |
| 54. |
Higher frequency transducers are normally used: |
| A. | In contact testing applications |
| B. | In angle beam testing applications |
| C. | In immersion testing applications |
| D. | Where deeper penetration is required |
| Answer» C. In immersion testing applications | |
| 55. |
Typical ultrasonic testing frequencies are: |
| A. | 50 kHz to 1 MHz |
| B. | 200 kHz to 25 MHz |
| C. | 10 MHz to 100 MHz |
| D. | 1 MHz to 5 MHz |
| Answer» D. 1 MHz to 5 MHz | |
| 56. |
‘25 million cycles per second’ can also be stated as: |
| A. | 25 kHz |
| B. | 2500 kHz |
| C. | 25 MHz |
| D. | 25 Hz |
| Answer» C. 25 MHz | |
| 57. |
A disadvantage of using a high frequency ultrasonic transducer is: |
| A. | It provides a smaller beam angle and better resolving power |
| B. | It provides a larger beam angle and poorer resolving power |
| C. | It is scattered more by coarse grained material |
| D. | It is scattered less by coarse grained material |
| Answer» C. It is scattered more by coarse grained material | |
| 58. |
Which of the following circuits provides timing signals to the pulser? |
| A. | The clock |
| B. | The amplifier |
| C. | The pulse generator |
| D. | The sweep generator |
| Answer» A. The clock | |
| 59. |
Which of the following search units would contain the thinnest quartz crystal? |
| A. | A 1 MHz search unit |
| B. | A 5 MHz search unit |
| C. | A 15 MHz search unit |
| D. | A 25 MHz search unit |
| Answer» D. A 25 MHz search unit | |
| 60. |
With longitudinal wave incident at angles between the first and second critical angles: |
| A. | The sound beam is totally reflected |
| B. | Only shear waves are produced in the second material |
| C. | Shear waves and longitudinal waves are produced in the second material |
| D. | Only longitudinal waves are produced in the second material |
| Answer» B. Only shear waves are produced in the second material | |
| 61. |
Sound velocity is described by which of the following relationships? |
| A. | Wavelength times frequency |
| B. | Wavelength divided by frequency |
| C. | Wavelength divided acoustic impedance |
| D. | Acoustic impedance divided by density |
| Answer» A. Wavelength times frequency | |
| 62. |
The relationship between the longitudinal wave incident angle and the refracted shear wave angle is defined by: |
| A. | Snell's law |
| B. | Snell's constant |
| C. | The law of acoustics |
| D. | Fraunhofer’s law |
| Answer» A. Snell's law | |
| 63. |
Acoustic impedance is defined by which of the following relations? |
| A. | Material density/wavelength |
| B. | Material density × velocity |
| C. | Velocity/wavelength |
| D. | Velocity × wavelength |
| Answer» B. Material density × velocity | |
| 64. |
The upper limit of human hearing is normally considered to be about: |
| A. | 12 kHz |
| B. | 16 kHz |
| C. | 20 kHz |
| D. | 30 kHz |
| Answer» C. 20 kHz | |
| 65. |
Reference standards containing a series of flat bottom holes of the same diameter at different depths in each block are called? |
| A. | Area-amplitude blocks |
| B. | Distance-amplitude blocks |
| C. | IIW blocks |
| D. | Sizing blocks |
| Answer» B. Distance-amplitude blocks | |
| 66. |
During ultrasonic testing by the immersion method, it is frequently necessary to angulate the search unit when a discontinuity is located at an angle in order to: |
| A. | Avoid a large number of back reflections that could interfere with a normal test pattern |
| B. | Obtain a maximum response if the discontinuity is not originally oriented perpendicular to the ultrasonic beam |
| C. | Obtain a discontinuity indication of the same height as the indication from the flat bottomed hole in a reference block |
| D. | Obtain the maximum number of entry surface reflections |
| Answer» B. Obtain a maximum response if the discontinuity is not originally oriented perpendicular to the ultrasonic beam | |
| 67. |
Which of the following transducer materials is the most efficient receiver of ultrasonic energy? |
| A. | Lead metaniobate |
| B. | Quartz |
| C. | Lithium sulphate |
| D. | Barium titanate |
| Answer» C. Lithium sulphate | |
| 68. |
An ultrasonic wave in which particle displacement is 90 degrees to the direction of wave propagation is called a: |
| A. | Longitudinal wave |
| B. | Shear wave |
| C. | Compressional wave |
| D. | Plate wave |
| Answer» B. Shear wave | |
| 69. |
An advantage of using lithium sulphate in search units it that: |
| A. | It is one of the most efficient generators of ultrasonic energy |
| B. | It is one of the most efficient receivers of ultrasonic energy |
| C. | It is insoluble |
| D. | It can withstand temperatures as high as 700ºC |
| Answer» B. It is one of the most efficient receivers of ultrasonic energy | |
| 70. |
Which of the following materials of the same alloy is most likely to produce the greatest amount of sound attenuation over a given distance? |
| A. | A hand forging |
| B. | A coarse grained casting |
| C. | An extrusion |
| D. | The attenuation is equal in all materials |
| Answer» B. A coarse grained casting | |
| 71. |
The ability to separate echos from reflectors close together in depth is called: |
| A. | Resolution |
| B. | Attenuation |
| C. | Accuracy |
| D. | Sensitivity |
| Answer» A. Resolution | |
| 72. |
Greater depth of penetration in coarse grained material may be achieved using: |
| A. | More sweep delay |
| B. | Higher frequencies |
| C. | Less sweep delay |
| D. | Lower frequencies |
| Answer» D. Lower frequencies | |
| 73. |
Lower frequency transducers produce: |
| A. | Deeper penetration, greater attentuation and less beam spread |
| B. | Deeper penetration, less attentuation and greater beam spread |
| C. | Greater beam spread but higher sensitivity and resolution |
| D. | Less beam spread but lower sensitivity and resolution |
| Answer» B. Deeper penetration, less attentuation and greater beam spread | |
| 74. |
Spurious indications might be caused by which of the following? |
| A. | Mode conversion from beam spread in a long specimen |
| B. | Surface waves generated during straight beam testing |
| C. | A test piece with a smooth machined surface |
| D. | All of the above |
| Answer» A. Mode conversion from beam spread in a long specimen | |
| 75. |
The portion of a test piece which is represented by the CRT screen area from zero to the rightmost edge of the initial pulse is called: |
| A. | The dead zone |
| B. | The near field |
| C. | The near zone |
| D. | The far zone |
| Answer» B. The near field | |
| 76. |
The depth of penetration of surface waves is approximately: |
| A. | One wavelength |
| B. | Three wavelengths |
| C. | 1/2 wavelength |
| D. | The total part thickness |
| Answer» A. One wavelength | |
| 77. |
An ultrasonic test using a straight beam contact search unit is being conducted through the thickness of a flat part such as a plate. This test should detect: |
| A. | Laminar-type flaws with major dimensions parallel to the rolled surface |
| B. | Transverse-type flaws with major dimensions at right angles to the rolled surface |
| C. | Radial flaws with major dimensions along length but radially oriented to the rolled surface |
| D. | None of the above |
| Answer» A. Laminar-type flaws with major dimensions parallel to the rolled surface | |
| 78. |
The first critical angle is defined as the longitudinal wave incident angle which results in: |
| A. | A refracted longitudinal wave of ninety degrees |
| B. | A refracted shear wave of ninety degrees |
| C. | Complete reflection of the shear wave |
| D. | None of the above |
| Answer» A. A refracted longitudinal wave of ninety degrees | |
| 79. |
The number of complete waves which pass a given point in a given period of time (usually one second) is referred to as the: |
| A. | Amplitude of a wave motion |
| B. | Pulse length of a wave motion |
| C. | Frequency of a wave motion |
| D. | Wavelength of a wave motion |
| Answer» C. Frequency of a wave motion | |
| 80. |
The speed of sound in a given material depends on: |
| A. | The specific acoustic impedance of the material |
| B. | The acoustic impedance and density of the material |
| C. | The density and elasticity of the material |
| D. | The piezo-electric resistance of the material |
| Answer» C. The density and elasticity of the material | |
| 81. |
AA screen pattern containing a large number of low-level indications (often reffered to as ‘hash’) could be caused by: |
| A. | A crack |
| B. | A large inclusion |
| C. | Coarse grained material |
| D. | Fine grained material |
| Answer» C. Coarse grained material | |
| 82. |
In an A scan presentation, the horizontal base line represents the: |
| A. | Amount of refracted ultrasonic sound energy |
| B. | Distance traveled by the search unit |
| C. | Elapsed time or distance |
| D. | None of the above |
| Answer» C. Elapsed time or distance | |
| 83. |
An ultrasonic instrument control which is used to expand or contract the horizontal base line of an A scan display is called: |
| A. | The sweep length or range control |
| B. | The damping control |
| C. | The sweep delay |
| D. | The pulse length control |
| Answer» A. The sweep length or range control | |
| 84. |
In a basic ultrasonic test pattern (A scan) for contact testing, the initial pulse (assume no sweep delay is used): |
| A. | Is the high indication on the extreme left side of the screen that represents the entry surface of the inspected part |
| B. | Is the first pulse that occurs near the right side of the screen and represents the opposite boundary of the inspected part |
| C. | Is an indication that appears and disappears during screening |
| D. | Is always the second pulse from the left on the viewing screen |
| Answer» A. Is the high indication on the extreme left side of the screen that represents the entry surface of the inspected part | |
| 85. |
AA term used in ultrasonics to express the rate at which sound waves pass through various substances is: |
| A. | Frequency |
| B. | Velocity |
| C. | Wave length |
| D. | Pulse length |
| Answer» B. Velocity | |
| 86. |
Transducer focal lengths are normally specified as: |
| A. | Distance in steel |
| B. | Distance in aluminium |
| C. | Distance in air |
| D. | Distance in water |
| Answer» A. Distance in steel | |
| 87. |
The second critical angle is defined as the longitudinal wave incident angle which results in: |
| A. | A refracted longitudinal wave of ninety degrees |
| B. | A refracted shear wave of ninety degrees |
| C. | Complete reflection of the sound beam |
| D. | None of the above |
| Answer» B. A refracted shear wave of ninety degrees | |
| 88. |
Spurious or nonrelevant indications might be suspected if: |
| A. | Indications are unusually consistent in amplitude and appearance |
| B. | There are strong indications in localised areas |
| C. | The indications are localised and repeatable |
| D. | None of the above |
| Answer» A. Indications are unusually consistent in amplitude and appearance | |
| 89. |
A A disadvantage of lithium sulfate as a transducer material is that: |
| A. | It is an inefficient receiver of ultrasonic energy |
| B. | It is soluble in water |
| C. | It is not piezo- electric |
| D. | It has extremely coarse grain structure |
| Answer» B. It is soluble in water | |
| 90. |
An advantage of using a ceramic transducer in search units is that: |
| A. | It is one of the most efficient generators of ultrasonic energy |
| B. | It is one of the most efficient receivers of ultrasonic energy |
| C. | It has a very low mechanical impedance |
| D. | It can withstand temperatures as high as 700oC |
| Answer» A. It is one of the most efficient generators of ultrasonic energy | |
| 91. |
The three most common modes of sound vibration are: |
| A. | Longitudinal, compressional, and transverse waves |
| B. | Longitudinal, transverse and rayleigh waves |
| C. | Transverse, longitudinal and shear waves |
| D. | Transverse, shear waves and rayleigh waves |
| Answer» B. Longitudinal, transverse and rayleigh waves | |
| 92. |
A A larger diameter crystal results in: |
| A. | Greater beam spread |
| B. | Lower penetrating power |
| C. | Less beam spread |
| D. | Greater penetrating power |
| Answer» C. Less beam spread | |
| 93. |
Entry surface resolution is a characteristic of an ultrasonic testing system which defines its ability to: |
| A. | Detect discontinuities oriented in a direction parallel to the ultrasonic beam |
| B. | Detect discontinuities located in the center of a forging containing a fine metallurgical structure |
| C. | Detect minute surface scratches |
| D. | Detect discontinuities located just beneath the entry surface in the part being tested |
| Answer» D. Detect discontinuities located just beneath the entry surface in the part being tested | |
| 94. |
Higher frequency transducers produce which of the following? |
| A. | Greater beam spread, sensitivity and resolution |
| B. | Greater sensitivity, resolution and penetration |
| C. | Greater penetration, attenuation and resolution |
| D. | Greater sensitivity, resolution and attenuation |
| Answer» D. Greater sensitivity, resolution and attenuation | |
| 95. |
In immersion testing, verification that the search unit is normal to a flat entry surface is indicated by: |
| A. | Maximum reflection from the entry surface |
| B. | Proper wavelength |
| C. | Maximum amplitude of the initial pulse |
| D. | Elimination of water multiples |
| Answer» A. Maximum reflection from the entry surface | |
| 96. |
Which of the following is true? |
| A. | Velocity = frequency/wavelength |
| B. | Frequency = velocity × wavelength |
| C. | Velocity = wavelength/frequency |
| D. | Wavelength=velocity/frequency |
| Answer» D. Wavelength=velocity/frequency | |
| 97. |
Most commercial ultrasonic testing is accomplished using frequencies between: |
| A. | 1 and 25 kHz |
| B. | 0.2 and 25 MHz |
| C. | 1 and 1 000 kHz |
| D. | 15 and 100 MHz |
| Answer» B. 0.2 and 25 MHz | |
| 98. |
The longitudinal wave incident angle which results in formation of a rayleigh wave is called: |
| A. | Normal incidence |
| B. | The first critical angle |
| C. | The second critical angle |
| D. | Any angle above the first critical angle |
| Answer» C. The second critical angle | |
| 99. |
An ultrasonic testing technique in which the transducer element is not parallel to the test surface is called: |
| A. | Angle beam testing |
| B. | Immersion testing |
| C. | Contact testing |
| D. | Through-transmission testing |
| Answer» A. Angle beam testing | |
| 100. |
In the same material, shear wave velocity is: |
| A. | Approximately 1/2 longitudinal wave velocity |
| B. | Approximately twice longitudinal wave velocity |
| C. | Approximately 1/4 longitudinal wave velocity |
| D. | Approximately four times longitudinal wave velocity |
| Answer» A. Approximately 1/2 longitudinal wave velocity | |
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