UT Level II Review Questions

Question 1

1. The wave mode that has multiple or varying wave velocities is:

a. longitudinal waves.
b. shear waves.
c. transverse waves.
d. lamb waves

Answer 1

d. lamb waves

Question 2

2. Which of the following would be considered application(s) of ultrasonic techniques?

a. Determination of a material’s coefficient of
expansion.
b. Study of a material’s metallurgical structure.
c. Determination of a material’s chemical
composition.
d. Evaluation of surface tension through capillary
action.

Answer 2

b. Study of a material’s metallurgical structure.

Question 3

3. The only significant sound wave mode that travels through a liquid is a:

a. shear wave.
b. longitudinal wave.
c. surface wave.
d. rayleigh wave.

Answer 3

b. longitudinal wave.

Question 4

4. The acoustic impedance of a material is used to determine the:

a. angle of refraction at an interface.
b. attenuation within the material.
c. relative amounts of sound energy coupled
through and reflected at an interface.
d. beam spread within the material.

Answer 4

c. relative amounts of sound energy coupled
through and reflected at an interface.

Question 5

5. When angle beam contact testing a test piece, increasing the incident angle until the second critical
   angle is reached may result in:

a. total reflection of a surface wave.
b. 45° refraction of the shear wave.
c. production of a surface wave.
d. a 90° angle of refraction for the wave.

Answer 5

c. production of a surface wave.

Question 6

6. Acoustic energy propagates in different modes. Which of the following represents a mode?

a. High-frequency ultrasonic waves.
b. A shear wave.
c. The dissipation factor.
d. The wave movement in the direction from the
point where the energy was introduced.

Answer 6

b. A shear wave.

Question 7

7. The simple experiment where a stick in a glass of
   water appears disjointed at the water surface illustrates the phenomenon of:

a. reflection.
b. magnification.
c. refraction.
d. diffraction.

Answer 7

c. refraction.

Question 8

8. The crystal thickness and transducer frequency are
   related. The thinner the crystal:

a. the lower the frequency.
b. the higher the frequency.
c. there is no appreciable effect.
d. the lower the attenuation

Answer 8

b. the higher the frequency.

Question 9

9. The random distribution of crystallographic
   direction in alloys with large crystalline structures is a factor in determining:

a. the body-centered cubic crystal system.
b. the angle of refraction.
c. scattering of sound.
d. material thickness.

Answer 9

c. scattering of sound.

Question 10

10. The length of the zone adjacent to a transducer in
    which fluctuations in sound pressure occur is mostly affected by the:

a. frequency of the transducer.
b. the sound beam exit point.
c. length of transducer cable.
d. diameter of the transducer.

Answer 10

d. diameter of the transducer.

Question 11

11. The differences in signals received from identical reflectors at different material distances from a transducer may be caused by:

a. material composition.
b. beam divergence.
c. acoustic impedance.
d. the piezoelectric effect.

Answer 11

b. beam divergence.

Question 12

12. It is possible for a discontinuity smaller than the transducer to produce indications of fluctuating amplitude as the transducer is moved laterally if testing is being performed in the:

a. fraunhofer zone.
b. near field.
c. snell field.
d. shadow zone.

Answer 12

b. near field.

Question 13

13. In immersion testing, the near-field effects of a transducer may be eliminated by:

a. increasing transducer frequency.
b. using a larger diameter transducer.
c. using an appropriate water path.
d. using a focused transducer.

Answer 13

c. using an appropriate water path

Question 14

14. In Figure 1, assuming a uniform beam pattern, what
    relationship would you expect to exist between the amplitudes of the reflected laminar signals at positions A and B?

a. 12 dB difference.
b. Equal amplitudes.
c. 2 to 1.
d. 3 to 1.

Answer 14

c. 2 to 1.

Question 15

15. In the far field of a uniform ultrasonic beam, sound
    intensity is ____________ the beam centerline.

a. minimum at
b. maximum at
c. maximum throughout twice the angle
where C is acoustic velocity, D is crystal diameter,
and f is frequency at
d. not related to orientation of

Answer 15

b. maximum at

Question 16

16. Which of the following may result in a long, narrow
    rod if the beam divergence results in a reflection from a side of the test piece before the sound wave reaches the back surface?

a. Multiple indications before the first back
reflection.
b. Indications from multiple surface reflections.
c. Conversion from the longitudinal mode to shear
mode at the perimeter of the beam.
d. Loss of front-surface indications.

Answer 16

c. Conversion from the longitudinal mode to shear
mode at the perimeter of the beam.

Question 17

17. Where does beam divergence occur?

a. Near field.
b. Far field.
c. At the crystal.
d. At the interface.

Answer 17

b. Far field.

Question 18

18. As frequency increases in ultrasonic testing, the angle
    of beam divergence of a given diameter crystal:

a. decreases.
b. remains unchanged.
c. increases.
d. varies uniformly through each wavelength.

Answer 18

a. decreases.

Question 19

19. As the radius of curvature of a curved lens is increased, the focal length of the lens:

a. increases.
b. decreases.
c. remains the same.
d. cannot be determined unless the frequency is
known.

Answer 19

a. increases.

Question 20

20. When examining materials for planar flaws oriented
    parallel to the part surface, what testing method is most often used?

a. Angle beam.
b. Through-transmission.
c. Straight beam.
d. Dual crystal.

Answer 20

c. Straight beam.

Question 21

21. If a contact angle beam transducer produces a 45°
    shear wave in steel, the angle produced by the same transducer in an aluminum specimen would be:
    (Vsteel = 0.323 cm/μs; VAL = 0.310 cm/μs)

a. less than 45°.
b. greater than 45°.
c. 45°.
d. unknown; more information is required.

Answer 21

a. less than 45°.

Question 22

22. Rayleigh waves are influenced most by
    discontinuities located:

a. close to or on the surface.
b. 1 wavelength below the surface.
c. 3 wavelengths below the surface.
d. 6 wavelengths below the surface.

Answer 22

a. close to or on the surface.

Question 23

23. The ultrasonic testing technique in which finger damping is most effective in locating a discontinuity is the:

a. shear wave technique.
b. longitudinal wave technique.
c. surface wave technique.
d. compressional wave technique.

Answer 23

c. surface wave technique.

Question 24

24. Lamb waves can be used to detect:

a. laminar-type discontinuities near the surface of a
thin material.
b. lack of fusion in the center of a thick weldment.
c. internal voids in diffusion bonds.
d. thickness changes in heavy plate material.

Answer 24

a. laminar-type discontinuities near the surface of a
thin material.

Question 25

25. The ratio of the velocity of sound in water compared
    to that for aluminum or steel is approximately:

a. 1:8.
b. 1:4.
c. 1:3.
d. 1:2.

Answer 25

b. 1:4.

Question 26

26. Which of the following scanning methods could be
    classified as an immersion-type test?

a. Contact angle beam testing.
b. Surface wave technique with a plastic transducer
wedge.
c. Scanning with a wheel-type transducer with the
transducer inside a liquid-filled tire.
d. Through-transmission technique with shear
waves.

Answer 26

c. Scanning with a wheel-type transducer with the
transducer inside a liquid-filled tire.

Question 27

27. In an immersion test of a piece of steel or aluminum, the water distance appears on the display as a fairly
    wide space between the initial pulse and the
    front-surface reflection because of:

a. reduced velocity of sound in water as compared
to the test specimen.
b. increased velocity of sound in water as compared to the test specimen.
c. temperature of the water.
d. viscosity of the water.

Answer 27

a. reduced velocity of sound in water as compared to the test specimen.

Question 28

28. Using the immersion method, a distance-amplitude
    curve (DAC) for a 19 mm (0.75 in.) diameter, 5 MHz transducer shows the high point of the DAC at the B/51 mm (2 in.) block. One day later, the high point of the DAC for the same transducer is at the
    J/102 mm (4 in.) block. Assuming that calibration has
    not changed, this would indicate that the transducer:

a. is improving in resolution.
b. is becoming defective.
c. has the beam of a contact testing transducer.
d. has a better definition.

Answer 28

b. is becoming defective.

Question 29

29. What law can be used to calculate the angle of refraction within a metal for both longitudinal and
    shear waves?

a. Poisson’s ratio law.
b. Snell’s law.
c. Fresnel’s field law.
d. Charles’ law.

Answer 29

b. Snell’s law.

Question 30

30. At an interface between two different materials, an impedance difference results in:

a. reflection of the entire incident energy at the interface.
b. absorption of sound.
c. division of sound energy into transmitted and reflected modes.
d. refraction of the entire incident energy at the interface.

Answer 30

c. division of sound energy into transmitted and reflected modes.

Question 31

31. When using focused transducers, nonsymmetry in a
    propagated sound beam may be caused by:

a. backing material variations.
b. mode conversion.
c. diffraction characteristics.
d. irregular sound beam exit point.

Answer 31

a. backing material variations.

Question 32

32. Ultrasonic wheel units may be used for which of the
    following types of examination?

a. Contact testing of aluminum plates.
b. Through-transmission testing of impeller shafts.
c. Longitudinal wave and/or shear wave examination.
d. Angle beam testing on beam-to-column T-joint
complete penetration welds.

Answer 32

c. Longitudinal wave and/or shear wave examination.

Question 33

33. During straight beam testing, test specimens with
    nonparallel front and back surfaces can cause:

a. partial or total loss of back reflection.
b. no loss in back reflection.
c. a widened (broad) back-reflection indication.
d. a focused (narrow) back-reflection indication.

Answer 33

a. partial or total loss of back reflection.

Question 34

34. In the immersion technique, the distance between the face of the transducer and the test surface (water
    path) is usually adjusted so that the time required to send the sound beam through the water is:

a. equal to the time required for the sound to travel
through the test piece.
b. greater than the time required for the sound to
travel through the test piece.
c. less than the time required for the sound to travel
through the test piece.
d. greater or less than the time required for the
sound to travel through the test piece depending
on water temperature and wave characteristics.

Answer 34

b. greater than the time required for the sound to
travel through the test piece.

Question 35

35. In a B-scan display, the length of a screen indication from a discontinuity is related to:

a. a discontinuity’s thickness as measured parallel to
the ultrasonic beam.
b. the discontinuity’s length in the direction of the
transducer travel.
c. the horizontal baseline elapsed time from left to
right.
d. the vertical and horizontal directions representing
the area over which the transducer was scanned.

Answer 35

b. the discontinuity’s length in the direction of the
transducer travel.

Question 36

36. Which circuit triggers the pulser and sweep circuits
    in an A-scan display?

a. Receiver-amplifier.
b. Power supply.
c. Clock.
d. Damping

Answer 36

c. Clock.

Question 37

37. On an A-scan display, the dead zone, refers to the:

a. distance contained within the near field.
b. area outside the beam spread.
c. distance covered by the front-surface pulse width
and recovery time.
d. area between the near field and the far field.

Answer 37

c. distance covered by the front-surface pulse width
and recovery time.

Question 38

38. On an A-scan display, what represents the intensity of a reflected beam?

a. Echo pulse width.
b. Horizontal screen location.
c. Signal brightness.
d. Signal amplitude

Answer 38

d. Signal amplitude

Question 39

39. Of the following scan types, which one can be used to
    produce a recording of discontinuitiy areas
    superimposed over a plan view of the test piece?

a. A-scan.
b. B-scan.
c. C-scan.
d. D-scan.

Answer 39

c. C-scan.

Question 40

40. In immersion testing in a small tank, a manually operated manipulator is used to:

a. manipulate the pulser/receiver unit and the
display.
b. set the proper transducer angle.
c. set the proper index function.
d. set the proper bridge distance.

Answer 40

b. set the proper transducer angle.

Question 41

41. In straight (normal) beam contact testing, which of the following would NOT result in a reduction in the
    back-surface reflection amplitude?

a. the usage of a high-viscosity couplant.
b. a discontinuity that is normal to the beam.
c. a near-surface discontinuity that cannot be
resolved from the main bang (initial pulse).
d. a coarse-grain material.

Answer 41

a. the usage of a high-viscosity couplant.

Question 42

42. A 152 mm (6 in.) diameter rod is being inspected for
    centerline cracks. The A-scan presentation for one complete path through the rod is as shown in Figure
43. The alarm gate should:

a. be used between points A and E.
b. be used at point D only.
c. be used between points B and D.
d. not be used for this application.

Answer 42

c. be used between points B and D.

Question 43

43. In an automatic scanning immersion unit, the bridge
    or carriage serves to:

a. support the manipulator and scanner tube and to
move it about transversely and longitudinally.
b. control the angular and transverse positioning of
the scanner tube.
c. control the vertical and angular positioning of the
scanner tube.
d. raise and lower the transducer

Answer 43

a. support the manipulator and scanner tube and to
move it about transversely and longitudinally.

Question 44

44. When adjusting the discontinuity-locating rule for a
    shear wave weld inspection, the zero point on the
    rule must coincide with the:

a. sound beam exit point of the wedge.
b. point directly over the discontinuity.
c. wheel transducer.
d. circular scanner.

Answer 44

a. sound beam exit point of the wedge.

Question 45

45. A special scanning device with the transducer mounted in a tire-like container filled with couplant is commonly called:

a. a rotating scanner.
b. an axial scanner.
c. a wheel transducer.
d. a circular scanner.

Answer 45

c. a wheel transducer.

Question 46

46. Which best describes a typical display of a crack
    whose major surface is perpendicular to the
    ultrasonic beam?

a. A broad indication.
b. A sharp indication.
c. The indication will not show due to improper
orientation.
d. A broad indication with high amplitude.

Answer 46

b. A sharp indication.

Question 47

47. A primary purpose of a reference standard is to:

a. provide a guide for adjusting instrument controls
to reveal discontinuities that are considered
harmful to the end use of the product.
b. give the technician a tool for determining exact
discontinuity size.
c. provide assurance that all discontinuities smaller
than a certain specified reference reflector are
capable of being detected by the test.
d. provide a standard reflector, which exactly
simulates natural discontinuities of a critical size.

Answer 47

a. provide a guide for adjusting instrument controls
to reveal discontinuities that are considered
harmful to the end use of the product.

Question 48

48. Compensation for the variation in echo height related
    to variations in discontinuity depth in the test
    material is known as:

a. transfer.
b. attenuation.
c. distance-amplitude correction.
d. interpretation.

Answer 48

c. distance-amplitude correction.

Question 49

49. Which of the following is a reference reflector that is
    not dependent on beam angle?

a. A flat-bottom hole.
b. A V-notch.
c. A side-drilled hole which is parallel to the plate
surface and perpendicular to the sound path.
d. A disk-shaped laminar reflector.

Answer 49

c. A side-drilled hole which is parallel to the plate
surface and perpendicular to the sound path.

Question 50

50. During a straight beam ultrasonic test, a
    discontinuity indication is detected that is small in amplitude compared to the loss in amplitude of back reflection. The orientation of this discontinuity is
    probably:

a. parallel to the test surface.
b. perpendicular to the sound beam.
c. parallel to the sound beam.
d. at an angle to the test surface

Answer 50

d. at an angle to the test surface

Question 51

51. A discontinuity is located having an orientation such
    that its long axis is parallel to the sound beam. The
    indication from such a discontinuity will be:

a. large in proportion to the length of the
discontinuity.
b. small in proportion to the length of the
discontinuity.
c. representative of the length of the discontinuity.
d. such that complete loss of back reflection will
result.

Answer 51

b. small in proportion to the length of the
discontinuity.

Question 52

52. Gas discontinuities are reduced to flat disks or other
    shapes parallel to the surface by:

a. rolling.
b. machining.
c. casting.
d. welding.

Answer 52

a. rolling.

Question 53

53. In which zone does the amplitude of an indication from a given discontinuity diminish exponentially as
    the distance increases?

a. Far-field zone.
b. Near-field zone.
c. Dead zone.
d. Fresnel zone.

Answer 53

a. Far-field zone.

Question 54

54. A smooth, flat discontinuity whose major plane is not
    perpendicular to the direction of sound propagation
    may be indicated by:

a. an echo amplitude comparable in magnitude to
the back-surface reflection, as well as complete
loss of the back-surface reflection.
b. an echo whose amplitude is steady across the
discontinuity surface.
c. an increase in backwall with no response from
discontinuity.
d. the absence of an indication.

Answer 54

a. an echo amplitude comparable in magnitude to
the back-surface reflection, as well as complete
loss of the back-surface reflection.

Question 55

55. Using a pulse echo technique, if the major plane of a
    flat discontinuity is oriented at some angle other than
    perpendicular to the direction of sound propagation,
    the result may be:

a. loss of signal linearity.
b. loss or lack of a received discontinuity echo.
c. focusing of the sound beam.
d. loss of interference phenomena.

Answer 55

b. loss or lack of a received discontinuity echo.

Question 56

56. As transducer diameter decreases, the beam spread:

a. decreases.
b. remains the same.
c. increases.
d. becomes conical in shape.

Answer 56

c. increases.

Question 57

57. A set of standard reference blocks with the same
    geometrical configuration and dimensions other than
    the size of the calibration reflectors, for example,
    flat-bottom holes, is called a set of:

a. distance-amplitude standards.
b. area-amplitude standards.
c. variable frequency blocks.
d. beam spread measuring blocks.

Answer 57

b. area-amplitude standards.

Question 58

58. The angle at which 90° refraction of a longitudinal
    sound wave is reached is called the:

a. angle of incidence.
b. first critical angle.
c. angle of maximum reflection.
d. second critical angle.

Answer 58

b. first critical angle.

Question 59

59. The control of voltage supplied to the vertical
    deflection plates of the instrument display in an
    A-scan UT setup is performed by the:

a. sweep generator.
b. pulser.
c. amplifier circuit.
d. clock timer.

Answer 59

c. amplifier circuit.

Question 60

60. Attenuation is a difficult quantity to measure
    accurately, particularly in solid materials, at the test
    frequencies normally used. The overall result usually
    observed includes other loss mechanisms, such as:

a. temperature.
b. scan rate.
c. fine grain structure.
d. beam spread.

Answer 60

d. beam spread.

Question 61

61. The most commonly used method of producing
    shear waves in a flat test part when inspecting by the
    immersion method is by:

a. transmitting longitudinal waves into a part in a
direction perpendicular to its front surface.
b. using two crystals vibrating at different
frequencies.
c. angulating the search tube or manipulator to the
proper angle.
d. using Y-cut quartz crystal.

Answer 61

c. angulating the search tube or manipulator to the
proper angle.

Question 62

62. Large grains in a metallic test specimen usually result
    in:

a. scatter, which becomes less pronounced as grain
size approaches wavelength.
b. increased penetration.
c. have no effect if a higher frequency is used.
d. large grass or hash or noise indications.

Answer 62

d. large grass or hash or noise indications.

Question 63

63. The total energy losses occurring in all materials is
    called:

a. attenuation.
b. scatter.
c. beam spread.
d. interface.

Answer 63

a. attenuation.

Question 64

64. Delay-tip (stand-off) type contact transducers are
    primarily used for:

a. discontinuity detection.
b. sound wave characterization.
c. thickness measurement or discontinuity detection
in thin materials.
d. attenuation measurements.

Answer 64

c. thickness measurement or discontinuity detection
in thin materials.

Question 65

65. Acoustical lenses are commonly used for contour
    correction. When scanning the inside of a pipe
    section by the immersion method, use a:

a. focused cup lens.
b. convex lens.
c. concave lens.
d. variable pitch lens.

Answer 65

b. convex lens.

Question 66

66. In Figure 3, transducer A is being used to establish:

a. verification of wedge angle.
b. sensitivity calibration.
c. resolution.
d. an index point.

Answer 66

d. an index point.

Question 67

67. In Figure 3, transducer C is being used to check:

a. distance calibration.
b. resolution.
c. sensitivity calibration.
d. verification of wedge angle.

Answer 67

c. sensitivity calibration.

Question 68

68. In Figure 3, transducer D is being used to check:

a. sensitivity calibration.
b. distance calibration.
c. resolution.
d. verification of wedge angle.

Answer 68

d. verification of wedge angle.

Question 69

69. When the incident angle is chosen to be between the
    first and second critical angles, the ultrasonic wave
    generated within the part will be:

a. longitudinal.
b. shear.
c. surface.
d. lamb.

Answer 69

b. shear.

Question 70

70. In Figure 4, transducer B is being used to check:

a. the verification of wedge angle.
b. resolution.
c. sensitivity calibration.
d. distance calibration

Answer 70

b. resolution.

Question 71

71. The angle at which 90° refraction of the shear wave
    mode occurs is called the:

a. first critical angle.
b. second critical angle.
c. third critical angle.
d. angle of reflection.

Answer 71

b. second critical angle.

Question 72

72. In a water immersion test, ultrasonic energy is
    transmitted into steel at an incident angle of 14°.
    What is the angle of the refracted shear wave within
    the material?
    V S = 3.2 × 10^5 cm/s
    V W = 1.5 × 10^5 cm/s
    (Trigonometry Tables Required)

a. 45°
b. 23°
c. 31°
d. 13°

Answer 72

c. 31°

Question 73

73. If you were requested to design a plastic shoe to
    generate a rayleigh wave in aluminum, what would
    be the incident angle of the ultrasonic energy?
    V A = 3.1 × 10^5 cm/s
    V P = 2.6 × 10^5 cm/s
    (Trigonometry Tables Required)

a. 37°
b. 57°
c. 75°
d. 48°

Answer 73

b. 57°

Question 74

74. Compute the wavelength of ultrasonic energy in lead
    at 1 MHz.

V L = 2.1 × 10^5 cm/s
V = λ × F
a. 0.21 cm
b. 21 cm
c. 0.48 cm
d. 4.8 × 10^5 cm

Answer 74

a. 0.21 cm

Question 75

75. For aluminum and steel, the longitudinal velocity is
    approximately _____ the shear velocity.

a. equal to
b. twice
c. half of
d. four times

Answer 75

b. twice

Question 76

76. Water travel distance for immersion inspections
    should be:

a. such that the second front reflection does not
appear between the first front and back
reflections.
b. exactly 76 mm (3 in.).
c. less than 76 mm (3 in.).
d. always equal to the thickness of the material
being inspected.

Answer 76

a. such that the second front reflection does not
appear between the first front and back
reflections.

Question 77

77. The electronic circuitry that allows selection and
    processing of only those signals relating to
    discontinuities that occur in specific zones of a part
    is called:

a. an electronic gate.
b. an electronic attenuator.
c. a distance amplitude correction circuit.
d. a fixed marker.

Answer 77

a. an electronic gate.

Question 78

78. When conducting a contact ultrasonic test, the grass
    or irregular signals that appear in the screen display
    of the area being inspected could be caused by:

a. fine grains in the structure.
b. dirt in the water couplant.
c. coarse grains in the structure.
d. a thick but tapered back surface.

Answer 78

c. coarse grains in the structure.

Question 79

79. In inspecting a 102 mm (4 in.) diameter threaded
    steel cylinder for radial cracks extending from the
    root of the threads, it would be preferable to transmit:

a. shear waves at an angle to the threads.
b. longitudinal waves from the end of the cylinder
and perpendicular to the direction of the thread
roots.
c. surface waves perpendicular to the thread roots.
d. shear waves around the circumference of the
cylinder.

Answer 79

b. longitudinal waves from the end of the cylinder
and perpendicular to the direction of the thread
roots.

Question 80

80. In an immersion inspection of raw steel material, the
    water travel distance should be:

a. exactly 76 mm (3 in.).
b. equal to 76 mm (3 in.) ±13 mm (±0.5 in.).
c. greater than one-fourth the thickness of the part.
d. equal to the thickness of a material.

Answer 80

c. greater than one-fourth the thickness of the part.

Question 81

81. 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 the angle of:

a. incidence.
b. refraction.
c. rarefaction.
d. reflection.

Answer 81

b. refraction.

Question 82

82. The process of adjusting an instrument or device to a
    reference standard is referred to as:

a. angulation.
b. scanning.
c. correcting for distance-amplitude variations.
d. calibration.

Answer 82

d. calibration.

Question 83

83. A grouping of a number of crystals in one transducer,
    with all contact surfaces in the same plane and
    vibrating in phase with each other to act as a single
    transducer is called a:

a. focusing crystal.
b. crystal mosaic.
c. scrubber.
d. single-plane manipulator.

Answer 83

b. crystal mosaic.

Question 84

84. The angle of reflection is:

a. equal to the angle of incidence.
b. dependent on the couplant used.
c. dependent on the frequency used.
d. equal to the angle of refraction.

Answer 84

a. equal to the angle of incidence.

Question 85

85. The angular position of the reflecting surface of a
    planar discontinuity with respect to the entry surface
    is referred to as:

a. the angle of incidence.
b. the angle of refraction.
c. the orientation of the discontinuity.
d. angle of reflection.

Answer 85

c. the orientation of the discontinuity.

Question 86

86. A short burst of alternating electrical energy is called:

a. a continuous wave.
b. a peaked DC voltage.
c. an ultrasonic wave.
d. a pulse.

Answer 86

d. a pulse.

Question 87

87. In ultrasonic testing, the time duration of the
    transmitted pulse is referred to as the:

a. pulse length or pulse width.
b. pulse amplitude.
c. pulse shape.
d. pulse distortion.

Answer 87

a. pulse length or pulse width.

Question 88

88. The phenomenon by which a wave strikes a
    boundary and changes the direction of its
    propagation within the same medium is referred to
    as:

a. divergence.
b. impedance.
c. angulation.
d. reflection.

Answer 88

d. reflection.

Question 89

89. The change in direction of an ultrasonic beam when
    it passes from one medium to another whose velocity
    differs from that of the first medium is called:

a. refraction.
b. rarefaction.
c. angulation.
d. reflection.

Answer 89

a. refraction.

Question 90

90. Which of the following modes of vibration exhibits
    the shortest wavelength at a given frequency and in a
    given material?

a. A longitudinal wave.
b. A compression wave.
c. A shear wave.
d. A surface wave.

Answer 90

d. A surface wave.

Question 91

91. In general, shear waves are more sensitive to small
    discontinuities than longitudinal waves for a given
    frequency and in a given material because:

a. the wavelength of shear waves is shorter than the
wavelength of longitudinal waves.
b. shear waves are not as easily dispersed in the
material.
c. the direction of particle vibration for shear waves
is more sensitive to discontinuities.
d. the wavelength of shear waves is longer than the
wavelength of longitudinal waves.

Answer 91

a. the wavelength of shear waves is shorter than the
wavelength of longitudinal waves.

Question 92

92. In general, which of the following modes of vibration
    would have the greatest penetrating power in a
    coarse-grained material if the frequency of the waves
    is the same?

a. Longitudinal waves.
b. Shear waves.
c. Transverse waves.
d. Rayleigh waves.

Answer 92

a. Longitudinal waves.

Question 93

93. A testing technique in which the crystal or
    transducer is parallel to the test surface and
    ultrasonic waves enter the material being tested in a
    direction perpendicular to the test surface is:

a. straight beam testing.
b. angle beam testing.
c. surface wave testing.
d. lamb wave.

Answer 93

a. straight beam testing.

Question 94

94. The distance from a given point on an ultrasonic
    wave to the next corresponding point is referred
    to as:

a. frequency.
b. wavelength.
c. velocity.
d. pulse length.

Answer 94

b. wavelength.

Question 95

95. The speed with which ultrasonic waves travel through a material is known as:

a. velocity.
b. pulse repetition rate.
c. pulse recovery rate.
d. ultrasonic response.

Answer 95

a. velocity.

Question 96

96. A substance that reduces the surface tension of a
    liquid is referred to as:

a. a couplant.
b. an ultrasonic dampener.
c. a wetting agent.
d. a solvent.

Answer 96

c. a wetting agent.

Question 97

97. The ultrasonic transducers most commonly used for
    discontinuity testing utilize:

a. magnetostriction principles.
b. piezoelectric principles.
c. mode conversion principles.
d. relative dialectric principles.

Answer 97

b. piezoelectric principles.

Question 98

98. Mechanical and electrical stability, insolubility in
    liquids, and resistance to aging are three advantages
    of transducers made of:

a. lithium sulfate.
b. barium titanate.
c. quartz.
d. rochelle salts.

Answer 98

c. quartz.

Question 99

99. The formula is referred to as:
    a. the acoustical impedance ratio formula.
    b. the phase conversion formula.
    c. the fresnel zone formula.
    d. Snell’s law.

Answer 99

d. Snell’s law.

Question 100

100. The formula is used to determine:

a. angular relationships.
b. phase velocities.
c. amount of reflected sound energy.
d. acoustic impedance.

Answer 100

a. angular relationships.

Question 101

101. The amount of energy reflected from a discontinuity
     is not dependent on the:

a. size of the discontinuity.
b. orientation of the discontinuity.
c. type of discontinuity.
d. filter setting.

Answer 101

d. filter setting.

Question 102

102. If an ultrasonic wave is transmitted through an interface of two materials in which the first material has a higher acoustic impedance value but the same
     velocity value as the second material, the angle of refraction will be:

a. greater than the angle of incidence.
b. less than the angle of incidence.
c. the same as the angle of incidence.
d. beyond the critical angle.

Answer 102

c. the same as the angle of incidence.

Question 103

103. Which one 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 103

d. 25 MHz

Question 104

104. The product of the sound velocity and the density of
     a material is known as the:

a. refraction value of the material.
b. acoustic impedance of the material.
c. elastic constant of the material.
d. Poisson’s ratio of the material.

Answer 104

b. acoustic impedance of the material.

Question 105

105. The amplifier range over which the unsaturated
     signal response increases in amplitude in proportion
     to the discontinuity surface area is the:

a. sensitivity range.
b. vertical linearity range.
c. selectivity range.
d. horizontal linearity range.

Answer 105

b. vertical linearity range.

Question 106

106. What kind of waves travel at a velocity slightly less
     than shear waves and their mode of propagation is
     both longitudinal and transverse with respect to the surface?

a. Rayleigh waves.
b. Transverse waves.
c. L-waves.
d. Longitudinal waves.

Answer 106

a. Rayleigh waves.

Question 107

107. Which ultrasonic test frequency would probably
     provide the best penetration in a 30 cm (12 in.) thick
     specimen of coarse-grained steel?

a. 1 MHz
b. 2.25 MHz
c. 5 MHz
d. 10 MHz

Answer 107

a. 1 MHz

Question 108

108. During immersion testing of an ASTM Ultrasonic
     Standard Reference Block, a B-scan presentation
     system will show a:

a. plan view of the block, showing the area and
position of the hole bottom as seen from the
entry surface.
b. basic test pattern showing the height of an
indication from the hold bottom and its location
in depth from the entry surface.
c. cross section of the reference block, showing the
top and bottom surfaces of the block and the
location of the hole bottom in the block.
d. cross-sectional view presentation with a vertical
signal representing the hole bottom and the
horizontal position representing its depth
position.

Answer 108

c. cross section of the reference block, showing the
top and bottom surfaces of the block and the
location of the hole bottom in the block.

Question 109

109. Properties of shear or transverse waves used for
     ultrasonic testing include:

a. particle motion normal to propagation direction,
and a propagation velocity that is about one-half
the longitudinal wave velocity in the same
material.
b. exceptionally high sensitivity due to low
attenuation resulting from longer wavelengths
when propagating through water.
c. high coupling efficiency because shear waves are
less sensitive to surface variables when traveling
from a coupling liquid to the part.
d. high sensitivity as a result of having a greater
wave velocity than longitudinal waves in the same
material.

Answer 109

a. particle motion normal to propagation direction,
and a propagation velocity that is about one-half
the longitudinal wave velocity in the same
material.

Question 110

110. One of the most common applications of ultrasonic
     tests employing shear waves is for the:

a. detection of discontinuities in welds,
tube and pipe.
b. determination of elastic properties of
metallic products.
c. detection of laminar discontinuities in
heavy plate.
d. measurement of thickness of thin plate.

Answer 110

a. detection of discontinuities in welds,
tube and pipe.

Question 111

111. Significant errors in ultrasonic thickness
     measurement can occur if:

a. the test frequency is varying at a constant rate.
b. the velocity of propagation deviates substantially
from an assumed constant value for a given
material.
c. water is employed as a couplant between the
transducer and the part being measured.
d. the echo-to-echo mode is used.

Answer 111

b. the velocity of propagation deviates substantially
from an assumed constant value for a given
material.

Question 112

112. Generally, the best ultrasonic testing method for
     detecting discontinuities oriented along the fusion
     zone in a welded plate is:

a. an angle beam contact method using surface
waves.
b. a contact test using a straight longitudinal wave.
c. an immersion test using surface waves.
d. an angle beam method using shear waves.

Answer 112

d. an angle beam method using shear waves.

Question 113

113. An ultrasonic testing instrument that displays pulses
     representing the magnitude of reflected ultrasound as
     a function of time or depth of metal is said to
     contain:

a. a continuous wave.
b. an A-scan presentation.
c. a B-scan presentation.
d. a C-scan presentation

Answer 113

b. an A-scan presentation.

Question 114

114. At a water-steel interface, the angle of incidence in
     water is 7°. The principal mode of vibration that
     exists in the steel is:

a. longitudinal.
b. shear.
c. lamb.
d. surface.

Answer 114

a. longitudinal.

Question 115

115. In a liquid medium, the only mode of vibration that
     can exist is:

a. longitudinal.
b. shear.
c. lamb.
d. surface.

Answer 115

a. longitudinal.

Question 116

116. In an ultrasonic instrument, the number of pulses
     produced by an instrument in a given period of time
     is known as the:

a. pulse length of the instrument.
b. pulse recovery time.
c. frequency.
d. pulse repetition frequency.

Answer 116

d. pulse repetition frequency.

Question 117

117. In a basic pulse echo ultrasonic instrument, the
     component that coordinates the action and timing of
     other components is called a:

a. display unit.
b. receiver.
c. marker circuit or range marker circuit.
d. timing section.

Answer 117

d. timing section.

Question 118

118. In a basic pulse echo ultrasonic instrument, the
     component that produces the voltage that activates
     the transducer is called:

a. an amplifier.
b. a receiver.
c. a pulser.
d. a synchronizer.

Answer 118

c. a pulser.

Question 119

119. In a basic pulse echo ultrasonic instrument, the
     component that produces the time baseline is called
     a:

a. sweep circuit.
b. receiver.
c. pulser.
d. synchronizer.

Answer 119

a. sweep circuit.

Question 120

120. In a basic pulse echo ultrasonic instrument, the
     component that produces visible signals on the
     screen which are used to measure distance is called a:

a. sweep circuit.
b. marker circuit.
c. receiver circuit.
d. synchronizer.

Answer 120

d. synchronizer.

Question 121

121. Most basic pulse echo ultrasonic instruments use:

a. automatic readout equipment.
b. an A-scan presentation.
c. a B-scan presentation.
d. a C-scan presentation.

Answer 121

b. an A-scan presentation.

Question 122

122. The instrument displays a plan view of the part
     outline and discontinuities when using:

a. automatic readout equipment.
b. an A-scan presentation.
c. a B-scan presentation.
d. a C-scan presentation.

Answer 122

d. a C-scan presentation.

Question 123

123. The incident angles at which 90° refraction of longitudinal and shear waves occurs are called the:

a. normal angles of incidence.
b. critical angles.
c. angles of maximum reflection.
d. mode angles.

Answer 123

b. critical angles.

Question 124

124. Compression 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 124

a. longitudinal waves.

Question 125

125. The mode of vibration that is quickly damped out
     when testing by the immersion method is:

a. longitudinal waves.
b. shear waves.
c. transverse waves.
d. surface waves.

Answer 125

d. surface waves.

Question 126

126. The motion of particles in a shear wave is:

a. parallel to the direction of propagation of the
ultrasonic beam.
b. transverse to the direction of beam propagation.
c. limited to the material surface and elliptical in
motion.
d. polarized in a plane at 45° to the direction of
beam propagation.

Answer 126

b. transverse to the direction of beam propagation.

Question 127

127. An ultrasonic longitudinal wave travels in aluminum
     with a velocity of 635 000 cm/s and has a frequency
     of 1 MHz. The wavelength of this ultrasonic wave is:

a. 6.35 mm (0.25 in.).
b. 78 mm (3.1 in.).
c. 1.9 m (6.35 ft).
d. 30 000 Å.

Answer 127

a. 6.35 mm (0.25 in.).

Question 128

128. The refraction angle of longitudinal ultrasonic waves
     passing from water into a metallic material at angles
     other than normal to the interface is primarily a
     function of the:

a. impedance ratio (r = Z wZm ) of water to metal.
b. relative velocities of sound in water and metal.
c. frequency of the ultrasonic beam.
d. density ratio of water to metal.

Answer 128

b. relative velocities of sound in water and metal.

Question 129

129. In contact testing, shear waves can be induced in the
     test material by:

a. placing an X-cut crystal directly on the surface of
the materials and coupling through a film of oil.
b. using two transducers on opposite sides of the
test specimen.
c. placing a spherical acoustic lens on the face of the
transducer.
d. using a transducer mounted on a plastic wedge so
that sound enters the part at an angle.

Answer 129

d. using a transducer mounted on a plastic wedge so
that sound enters the part at an angle.

Question 130

130. As frequency increases in ultrasonic testing, the angle
     of beam divergence of a given diameter crystal:

a. decreases.
b. remains unchanged.
c. increases.
d. varies uniformly through each wavelength

Answer 130

a. decreases.

Question 131

131. Which of the following is not an advantage of contact
     ultrasonic transducers (probes) adapted with plastic
     shoes?

a. Most of the crystal wear is eliminated.
b. Adaptation to curved surfaces is permitted.
c. Sensitivity is increased.
d. Ultrasound is allowed to enter a part’s surface at
oblique angles.

Answer 131

c. Sensitivity is increased.

Question 132

132. The velocity of sound is the lowest in:

a. air.
b. water.
c. aluminum.
d. plastic.

Answer 132

a. air.

Question 133

133. A longitudinal ultrasonic wave is transmitted from
     water into steel at an angle of 5° from the normal.
     In such a case, the refracted angle of the transverse
     wave is:

a. less than the refracted angle of the longitudinal
wave.
b. equal to the refracted angle of the longitudinal
wave.
c. greater than the refracted angle of the
longitudinal wave.
d. not present at all.

Answer 133

a. less than the refracted angle of the longitudinal
wave.

Question 134

134. The velocity of longitudinal waves is the highest in:
     a. water.
     b. air.
     c. aluminum.
     d. plastic.

Answer 134

c. aluminum.

Question 135

135. In steel, the velocity of sound is greatest in:

a. longitudinal waves.
b. shear waves.
c. surface waves.
d. lamb waves

Answer 135

a. longitudinal waves.

Question 136

136. The acoustic impedance is:

a. used to calculate the angle of reflection.
b. the product of the density of the material and the
velocity of sound in the material.
c. found by Snell’s law.
d. used to determine resonance values.

Answer 136

b. the product of the density of the material and the
velocity of sound in the material.

Question 137

137. Thin sheet may be inspected with the ultrasonic wave
     directed normal to the surface by observing the:
     a. amplitude of the front-surface reflection.
     b. multiple reflection pattern.
     c. attenuation rate.
     d. ratio of shear and longitudinal velocities.

Answer 137

b. multiple reflection pattern.

Question 138

138. A diagram in which the entire circuit stage or
     sections are shown by geometric figures and the path
     of the signal or energy by lines and/or arrows is
     called a:

a. schematic diagram.
b. blueprint.
c. block diagram.
d. circuit layout.

Answer 138

c. block diagram.

Question 139

139. A void caused by gas entrapped in a casting is called:

a. a burst.
b. a cold shut.
c. flaking.
d. a blowhole.

Answer 139

d. a blowhole.

Question 140

140. A discontinuity that occurs during the casting of
     molten metal which may be caused by the splashing,
     surging, interrupted pouring, or the meeting of two
     streams of metal coming from different directions is
     called:

a. a burst.
b. a cold shut.
c. flaking.
d. a blowhole

Answer 140

b. a cold shut.

Question 141

141. The ratio between the wave speed in one material
     and the wave speed in a second material is called:

a. the acoustic impedance of the interface.
b. Young’s modulus.
c. Poisson’s ratio.
d. refractive index.

Answer 141

d. refractive index.

Question 142

142. The expansion and contraction of a magnetic
     material under the influence of a changing magnetic
     field is referred to as:

a. piezoelectricity.
b. refraction.
c. magnetostriction.
d. rarefaction.

Answer 142

c. magnetostriction.

Question 143

143. The ratio of stress to strain in a material within the
     elastic limit is called:

a. Young’s modulus.
b. the impedance ratio.
c. Poisson’s ratio.
d. refractive index.

Answer 143

a. Young’s modulus.

Question 144

144. When setting up for an ultrasonic inspection, the
     pulse repetition rate of the instrument must be:

a. low enough so that transmitted waves will not
interfere with reflected signals.
b. immaterial as the pulse repetition rate does not
affect the ability to detect indications regardless of
size.
c. slow enough to allow the instrument display to
refresh with each pulse.
d. fast enough for the operator to be able to rely on
the discontinuity alarm instead of constantly
watching the screen.

Answer 144

a. low enough so that transmitted waves will not
interfere with reflected signals.

Question 145

145. The factor that determines the amount of reflection
     at the interface of two dissimilar materials is:

a. the index of rarefaction.
b. the frequency of the ultrasonic wave.
c. Young’s modulus.
d. the acoustic impedance.

Answer 145

d. the acoustic impedance.

Question 146

146. A quartz crystal cut so that its major faces are parallel
     to the Z and Y axes and perpendicular to the X axis is
     called:

a. a Y-cut crystal.
b. an X-cut crystal.
c. a Z-cut crystal.
d. a ZY-cut crystal.

Answer 146

b. an X-cut crystal.

Question 147

147. The equation describing wavelength in terms of
     velocity and frequency is:

a. wavelength = velocity × frequency.
b. wavelength = z (frequency × velocity).
c. wavelength = velocity ÷ frequency.
d. wavelength = frequency + velocity.

Answer 147

c. wavelength = velocity ÷ frequency.

Question 148

148. When an ultrasonic beam reaches the interface of
     two dissimilar materials, it can be:

a. 100% reflected.
b. 100% absorbed.
c. partially reflected and refracted, but not absorbed.
d. partially reflected, refracted, and transmitted.

Answer 148

d. partially reflected, refracted, and transmitted.

Question 149

149. When inspecting aluminum by the immersion
     method using water for a couplant, the following
     information is known:
     velocity of sound in water = 1.49 × 105 cm/s,
     velocity of longitudinal waves in aluminum =
     6.32 × 105 cm/s, and angle of incidence = 5°.
     The angle of refraction for longitudinal waves is
     approximately:

a. 22°
b. 18°
c. 26°
d. 16°

Answer 149

a. 22°

Question 150

150. Of the piezoelectric materials listed below, the most
     efficient sound transmitter is:

a. lithium sulfate.
b. quartz.
c. barium titanate.
d. silver oxide.

Answer 150

c. barium titanate.

Question 151

151. Of the piezoelectric materials listed below, the most
     efficient sound receiver is:

a. lithium sulfate.
b. quartz.
c. barium titanate.
d. silver oxide.

Answer 151

a. lithium sulfate.

Question 152

152. The most commonly used method of producing
     shear waves in a test part when inspecting by the
     immersion method is by:

a. transmitting longitudinal waves into a part in a
direction perpendicular to its front surface.
b. using two crystals vibrating at different
frequencies.
c. using a Y-cut quartz crystal.
d. angulating the search tube to the proper angle.

Answer 152

d. angulating the search tube to the proper angle.

Question 153

153. Beam divergence is a function of the dimensions of
     the crystal and the wavelength of the beam
     transmitted through a medium, and it:

a. increases if the frequency or crystal diameter
decreases.
b. decreases if the frequency or crystal diameter
decreases.
c. increases if the frequency increases and crystal
diameter decreases.
d. decreases if the frequency increases and crystal
diameter decreases.

Answer 153

a. increases if the frequency or crystal diameter
decreases.

Question 154

154. The wavelength of an ultrasonic wave is:

a. directly proportional to velocity and frequency.
b. directly proportional to velocity and inversely
proportional to frequency.
c. inversely proportional to velocity and directly
proportional to frequency.
d. equal to the product of velocity and frequency.

Answer 154

b. directly proportional to velocity and inversely
proportional to frequency.

Question 155

155. The fundamental frequency of a piezoelectric crystal
     is primarily a function of the:

a. length of the applied voltage pulse.
b. amplifying characteristics of the pulse amplifier in
the instrument.
c. thickness of the crystal.
d. material testing.

Answer 155

c. thickness of the crystal.

Question 156

156. Acoustic velocities of materials are primarily due to
     the material’s:

a. density and elasticity.
b. material thickness.
c. temperature.
d. acoustic impedance.

Answer 156

a. density and elasticity.

Question 157

157. Inspection of castings is often impractical because of:

a. extremely small grain structure.
b. coarse grain structure.
c. uniform flow lines.
d. uniform velocity of sound.

Answer 157

b. coarse grain structure.

Question 158

158. Lamb waves may be used to inspect:

a. forgings.
b. bar stock.
c. ingots.
d. thin sheet.

Answer 158

d. thin sheet.

Question 159

159. The formula used to determine the angle of beam
     divergence of a quartz crystal is:

a. sin θ = diameter r 1/2 × wavelength.
b. sin θ diameter = frequency × wavelength.
c. sin θ = frequency × wavelength.
d. sin θ/2 = 1.22 × wavelength/diameter.

Answer 159

d. sin θ/2 = 1.22 × wavelength/diameter.

Question 160

160. The resolving power of a transducer is directly
     proportional to its:

a. diameter.
b. bandwidth.
c. pulse repetition.
d. Poisson’s ratio.

Answer 160

b. bandwidth.

Question 161

161. Acoustic lens elements with which of the following
     permit focusing the sound energy to enter cylindrical
     surfaces normally or along a line focus?

a. Cylindrical curvatures.
b. Spherical lens curvatures.
c. Convex shapes.
d. Concave shapes.

Answer 161

a. Cylindrical curvatures.

Question 162

162. In the basic pulse echo instrument, the synchronizer,
     clock or timer circuit determines the:

a. pulse length.
b. gain.
c. pulse repetition rate.
d. sweep length.

Answer 162

c. pulse repetition rate.

Question 163

163. The primary requirement of a paintbrush transducer
     is that:

a. all crystals be mounted equidistant from each
other.
b. the intensity of the beam pattern not vary greatly
over the entire length of the transducer.
c. the fundamental frequency of the crystals not
vary more than 0.01%.
d. the overall length not exceed 76 mm (3 in.).

Answer 163

b. the intensity of the beam pattern not vary greatly
over the entire length of the transducer.

Question 164

164. Heat conduction, viscous friction, elastic hysteresis,
     and scattering are four different mechanisms that
     lead to:

a. attenuation.
b. refraction.
c. beam spreading.
d. saturation

Answer 164

a. attenuation.

Question 165

165. Because the velocity of sound in aluminum is
     approximately 245 000 in./s, for sound to travel
     through 25 mm (1 in.) of aluminum, it takes:

a. 1/8 s
b. 4 μs
c. 4 ms
d. 1/4 ×104 s

Answer 165

b. 4 μs

Question 166

166. When testing a part with a rough surface, it is
     generally advisable to use a:

a. lower frequency transducer and a more viscous
couplant than is used on parts with a smooth
surface.
b. higher frequency transducer and a more viscous
couplant than is used on parts with a smooth
surface.
c. higher frequency transducer and a less viscous
couplant than is used on parts with a smooth
surface.
d. lower frequency transducer and a less viscous
couplant than is used on parts with a smooth
surface

Answer 166

a. lower frequency transducer and a more viscous
couplant than is used on parts with a smooth
surface.

Question 167

167. Reflection indications from a weld area being
     inspected by the angle beam technique may
     represent:

a. porosity.
b. backwall.
c. initial pulse.
d. hot tears.

Answer 167

a. porosity.

Question 168

168. During a test using A-scan equipment, strong
     indications that move at varying rates across the
     screen in the horizontal direction appear. It is
     impossible to repeat a particular screen pattern by
     scanning the same area. A possible cause of these
     indications is:

a. porosity in the test part.
b. an irregularly shaped crack.
c. a blowhole.
d. electrical interference.

Answer 168

d. electrical interference.

Question 169

169. In an A-scan presentation, position along the
     horizontal baseline indicates:

a. a square wave pattern.
b. a sweep line.
c. a marker pattern.
d. elapsed time.

Answer 169

d. elapsed time.

Question 170

170. The greatest amount of attenuation losses take place
     at:
     a. 1 MHz
     b. 2.25 MHz
     c. 5 MHz
     d. 10 MHz

Answer 170

d. 10 MHz

Question 171

171. Waves that travel around gradual curves with little or
     no reflection from the curve are called:

a. transverse waves.
b. surface waves.
c. shear waves.
d. longitudinal waves.

Answer 171

b. surface waves.

Question 172

172. To evaluate and accurately locate discontinuities after
     scanning a part with a paintbrush transducer, it is
     generally necessary to use a:

a. transducer with a smaller crystal.
b. scrubber.
c. grid map.
d. crystal collimator.

Answer 172

a. transducer with a smaller crystal.

Question 173

173. An ultrasonic instrument has been calibrated to
     obtain an 80% FSH indication from a 2 mm (0.08 in.)
     diameter flat-bottom hole located 76 mm (3 in.) from
     the front surface of an aluminum reference block.
     When testing an aluminum forging, an 80% FSH
     indication is obtained from a discontinuity located
     76 mm (3 in.) from the entry surface. The reflective
     area of this discontinuity is probably:

a. the same as the area of the 2 mm (0.08 in.)
flat-bottom hole.
b. greater than the area of the 2 mm (0.08 in.)
flat-bottom hole.
c. slightly less than the area of the 2 mm (0.08 in.)
flat-bottom hole.
d. about one-half the area of the 2 mm (0.08 in.)
flat-bottom hole.

Answer 173

b. greater than the area of the 2 mm (0.08 in.)
flat-bottom hole.

Question 174

174. As the impedance ratio of two dissimilar materials
     increases, the percentage of sound coupled through
     an interface of such materials:

a. decreases.
b. increases.
c. is not changed.
d. may increase or decrease.

Answer 174

a. decreases.

Question 175

175. Lower frequency sound waves are not generally used
     for pulse echo testing of thinner materials because of:

a. the rapid attenuation of low frequency sound.
b. incompatible wavelengths.
c. poor near-surface resolution.
d. fraunhofer field effects.

Answer 175

c. poor near-surface resolution.

Question 176

176. In immersion testing, the accessory equipment to
     which the search cable and the transducer are
     attached is called a:

a. crystal collimator.
b. scrubber.
c. jet-stream unit.
d. search tube or scanning tube.

Answer 176

d. search tube or scanning tube.

Question 177

177. In general, discontinuities in wrought products tend
     to be oriented:

a. randomly.
b. in the direction of grain flow.
c. at right angles to the entry surface.
d. at right angles to the grain flow.

Answer 177

b. in the direction of grain flow.

Question 178

178. In immersion testing of round bars, the back surface
     contour may result in:

a. loss of back reflection.
b. additional indications following the direct back
surface reflection.
c. inability to distinguish the actual distance to the
back-surface reflection.
d. false indications of discontinuities near the back
surface.

Answer 178

a. loss of back reflection.

Question 179

179. In contact testing, discontinuities near the entry
     surface cannot always be detected because of:

a. the far-field effect.
b. attenuation.
c. the dead zone.
d. refraction

Answer 179

c. the dead zone.

Question 180

180. In cases where the diameter of tubing being inspected
     is smaller than the diameter of the transducer, what
     can be used to confine the sound beam to the proper
     range of angles?

a. A scrubber.
b. A collimator.
c. An angle plane angulator.
d. A jet-stream unit.

Answer 180

b. A collimator.

Question 181

181. Which of the following is more likely to limit the
     maximum scanning speed in immersion testing?

a. The frequency of the transducer.
b. Viscous drag problems.
c. The pulse repetition rate of the test instrument.
d. The persistency of the ultrasonic instrument
display.

Answer 181

c. The pulse repetition rate of the test instrument.

Question 182

182. The property of certain materials to transform
     electrical energy to mechanical energy and vice versa
     is called:

a. mode conversion.
b. piezoelectric effect.
c. refraction.
d. impedance matching.

Answer 182

b. piezoelectric effect.

Question 183

183. Surface waves energy levels are concentrated at what
     depth below the surface?

a. 25 mm (1 in.).
b. 102 mm (4 in.).
c. 1 wavelength.
d. 4 wavelengths

Answer 183

c. 1 wavelength.

Question 184

184. To prevent the appearance of the second front surface
     indication before the first back reflection when
     inspecting aluminum by the immersion method
     (water is used as a couplant), it is necessary to have a
     minimum of at least 25 mm (1 in.) of water for every
     _____ of aluminum.

a. 51 mm (2 in.)
b. 102 mm (4 in.)
c. 152 mm (6 in.)
d. 203 mm (8 in.)

Answer 184

b. 102 mm (4 in.)

Question 185

185. Increasing the length of the pulse used to activate the
     transducer will:

a. increase the strength of the ultrasound but
decrease the resolving power of the instrument.
b. increase the resolving power of the instrument.
c. have no effect on the test.
d. decrease the penetration of the sound wave.

Answer 185

a. increase the strength of the ultrasound but
decrease the resolving power of the instrument.

Question 186

186. The lack of parallelism between the entry surface and
     the back surface:

a. may result in a screen pattern that does not
contain back reflection indications.
b. makes it difficult to locate discontinuities that lie
parallel to the entry surface.
c. usually indicates that a porous condition exists in
the metal.
d. decreases the penetrating power of the test.

Answer 186

a. may result in a screen pattern that does not
contain back reflection indications.

Question 187

187. A discontinuity with a concave surface will:

a. diffuse the sound energy throughout the part.
b. cause the reflected beam to focus at a point
determined by the curvature of the discontinuity.
c. cause mode reinforcement of the ultrasonic wave.
d. propagate due to sound energy.

Answer 187

b. cause the reflected beam to focus at a point
determined by the curvature of the discontinuity.

Question 188

188. Rayleigh waves:

a. are generated at the first critical angle.
b. are generated at the second critical angle.
c. are generated at either critical angle.
d. travel only in a liquid.

Answer 188

b. are generated at the second critical angle.

Question 189

189. Angle beam testing of plate will often miss:

a. cracks that are perpendicular to the sound wave.
b. inclusions that are randomly oriented.
c. laminations that are parallel to the front surface.
d. a series of small discontinuities.

Answer 189

c. laminations that are parallel to the front surface.

Question 190

190. Reducing the extent of the dead zone of a transducer
     by using a delay tip results in:

a. improved distance-amplitude correction in the
near field.
b. reduced frequency of the primary ultrasonic
beam.
c. reduced ability to detect discontinuities in the
near field.
d. improved accuracy in thickness measurement of
thin plate and sheet.

Answer 190

d. improved accuracy in thickness measurement of thin plate and sheet.

Question 191

191. In a plate, skip distance can be calculated from which
     of the following formulas where (t = plate thickness,
     θ = angle of sound beam refraction, and V = sound
     velocity):

a. S = (2 × t )/tan θ.
b. S = 2 × t × sin θ.
c. S = 2 × t × tan θ.
d. S = 2 ×V × sin θ.

Answer 191

c. S = 2 × t × tan θ.

Question 192

192. The technique of examining an ultrasonic reflector
     from different directions might be used to enable the
     technician to:

a. distinguish between different types of
discontinuities.
b. predict the useful service life of the test specimen.
c. distinguish between discontinuity indications and
spurious or false indications.
d. accept an indication that appeared to be rejectable
from the first test direction.

Answer 192

a. distinguish between different types of
discontinuities.

Question 193

193. Attenuation is the loss of the ultrasonic wave energy
     during the course of propagation in the material due
     to:

a. reflection and refraction.
b. dispersion and diffraction.
c. absorption and scattering.
d. composition and shape.

Answer 193

c. absorption and scattering.

Question 194

194. In immersion shear wave testing, waves are normally
     generated by angulating the transducer beyond the
     first critical angle. What is the direction of the
     material’s particle motion?

a. The same as the wave propagation.
b. Normal to the material surface.
c. Parallel to the direction of wave propagation.
d. Perpendicular to the direction of wave
propagation.

Answer 194

d. Perpendicular to the direction of wave
propagation.

Question 195

195. Which of the following modes of vibration are
     quickly dampened out when testing by the
     immersion method?

a. Longitudinal waves.
b. Shear waves.
c. Transverse waves.
d. Surface waves.

Answer 195

d. Surface waves.

Question 196

196. Which ultrasonic test frequency would probably
     provide the best penetration in a 30 cm (12 in.) thick
     specimen of coarse-grained steel?

a. 1 MHz
b. 2.25 MHz
c. 5 MHz
d. 10 MHz

Answer 196

a. 1 MHz

Question 197

197 A quartz crystal cut so that its major faces are parallel
to the Z and Y axes and perpendicular to the X axis is called:

a. a Y-cut crystal.
b. an X-cut crystal.
c. a Z-cut crystal.
d. a ZY-cut crystal.

Answer 197

b. an X-cut crystal.