UT Level III Review Questions

Question 1

1. In an ultrasonic test system where signal
   amplitudes are displayed, an advantage of a
   frequency-independent attenuator over a
   continuously variable gain control is that the:

a. pulse shape distortion is less.
b. signal amplitude measured using the attenuator
is independent of frequency.
c. dynamic range of the system is decreased.
d. effect of amplification threshold is avoided.

Answer 1

b. signal amplitude measured using the attenuator
is independent of frequency.

Question 2

2. An amplifier in which received echo pulses must
   exceed a certain threshold voltage before they can be
   indicated might be used to:

a. suppress amplifier noise, unimportant scatter
echoes, or small discontinuity echoes that are of
no consequence.
b. provide a display with nearly ideal vertical
linearity characteristics.
c. compensate for the unavoidable effects of material
attenuation losses.
d. provide distance-amplitude correction
automatically.

Answer 2

a. suppress amplifier noise, unimportant scatter
echoes, or small discontinuity echoes that are of
no consequence.

Question 3

3. The output voltage from a saturated amplifier is:

a. 180° out of phase from the input voltage.
b. lower than the input voltage.
c. nonlinear with respect to the input voltage.
d. below saturation.

Answer 3

c. nonlinear with respect to the input voltage.

Question 4

4. The transmitted pulse at the output of the pulser
   usually has a voltage of 100 to 1000 V, whereas the
   voltages of the echoes at the input of the amplifier are
   on the order of:

a. 0.001-1 V
b. 1-5 V
c. 10 V
d. 50 V

Answer 4

a. 0.001-1 V

Question 5

5. The intended purpose of the adjustable calibrated
   attenuator of an ultrasonic instrument is to:

a. control transducer damping.
b. increase the dynamic range of the instrument.
c. broaden the frequency range.
d. attenuate the voltage applied to the transducer.

Answer 5

b. increase the dynamic range of the instrument.

Question 6

6. Which of the following might result in increased
   transmission of ultrasound within a coarse-grained
   material?

a. Perform the examination with a smaller diameter
transducer.
b. Perform the examination after a grain-refining
heat treatment.
c. Change from a contact examination to an
immersion examination.
d. Change from a longitudinal to a transverse wave

Answer 6

b. Perform the examination after a grain-refining
heat treatment.

Question 7

7. The term that is used to determine the relative
   transmittance and reflectance of ultrasonic energy at
   an interface is called:

a. acoustic attenuation.
b. interface refraction.
c. acoustic impedance ratio.
d. acoustic frequency.

Answer 7

c. acoustic impedance ratio.

Question 8

8. In a forging, discontinuities associated with
   nonmetallic inclusions can most accurately be
   described as being:

a. oriented parallel to the major axis.
b. parallel to the minor axis.
c. aligned with forging flow lines.
d. oriented at approximately 45° to the forging
direction.

Answer 8

c. aligned with forging flow lines.

Question 9

9. The preferred method of ultrasonically inspecting a
   complex-shaped forging:

a. is an automated immersion test of the finished
forging using an instrument containing a
calibrated attenuator in conjunction with a
C-scan recorder.
b. combines thorough inspection of the billet prior
to forging with a careful inspection of the finished
part in all areas where the shape permits.
c. is a manual contact test of the finished part.
d. is an automated immersion test of the billet prior
to forging.

Answer 9

b. combines thorough inspection of the billet prior
to forging with a careful inspection of the finished
part in all areas where the shape permits.

Question 10

10. When maximum sensitivity is required from a
    transducer:

a. a straight beam unit should be used.
b. large-diameter crystals are required.
c. the piezoelectric element should be driven at its
fundamental resonant frequency.
d. the bandwidth of the transducer should be as
large as possible.

Answer 10

c. the piezoelectric element should be driven at its
fundamental resonant frequency.

Question 11

11. The sensitivity of an ultrasonic test system:

a. depends on the transducer, pulser, and amplifier
used.
b. decreases as the frequency is increased.
c. increases as the resolution increases.
d. is not related to mechanical damping or the
transducer.

Answer 11

a. depends on the transducer, pulser, and amplifier
used.

Question 12

12. The ability of a test system to separate the back
    surface echo and the echo from a small discontinuity
    just above this back surface:

a. depends primarily upon the pulse length
generated from the instrument.
b. is not related to the surface roughness of the part
under inspection.
c. is primarily related to the thickness of the part
under inspection.
d. is usually improved by using a larger diameter
transducer.

Answer 12

a. depends primarily upon the pulse length
generated from the instrument.

Question 13

13. Transducer sensitivity is most often determined by:

a. calculations based on frequency and thickness of
the piezoelectric element.
b. the amplitude of the response from an artificial
discontinuity.
c. comparing it to a similar transducer made by the
same manufacturer.
d. determining the ringing time of the transducer.

Answer 13

b. the amplitude of the response from an artificial
discontinuity.

Question 14

14. Side-drilled holes are frequently used as reference
    reflectors for:

a. distance-amplitude calibration for shear waves.
b. area-amplitude calibration.
c. thickness calibration of plate.
d. determining near-surface solutions.

Answer 14

a. distance-amplitude calibration for shear waves.

Question 15

15. Notches provide good reference discontinuities when
    a UT examination is conducted to primarily detect
    discontinuities such as:

a. porosity in rolled plate.
b. inadequate penetration at the root of a weld.
c. weld porosity.
d. internal inclusions.

Answer 15

b. inadequate penetration at the root of a weld.

Question 16

16. The difference between a compression and shear
    wave is:

a. quantitative measure.
b. relative particle vibration direction.
c. qualitative measure.
d. amplitude.

Answer 16

b. relative particle

Question 17

17. The particle motion for rayleigh waves is usually
    described as:

a. sinusoidal.
b. circular.
c. elliptical.
d. shear.

Answer 17

c. elliptical.

Question 18

18. Based upon wave theory and ignoring attenuation
    losses, the echo amplitude of a finite reflector is:

a. directly proportional to the distance to the
reflector.
b. inversely proportional to the distance to the
reflector.
c. directly proportional to the square of the
diameter of the circular reflector.
d. inversely proportional to the square of the
diameter of the circular reflector.

Answer 18

c. directly proportional to the square of the
diameter of the circular reflector.

Question 19

19. The rate generator in B-scan equipment will
    invariably be directly connected to the:

a. display intensity circuit.
b. pulser circuit.
c. RF amplifier circuit.
d. horizontal sweep circuit.

Answer 19

b. pulser circuit.

Question 20

20. In A-scan equipment, the RF pulser output voltage is
    normally in the range of:

a. 1-10 V.
b. 10-100 V.
c. 100-1000 V.
d. 1000-3000 V.

Answer 20

c. 100-1000 V.

Question 21

21. When contact testing, an increase in tightness of a
    shrink fit to a hollow shaft will cause the ratio of the
    back reflection to the metal-to-metal interface
    reflection to:

a. increase.
b. decrease.
c. remain unchanged.
d. not be predicted as the response is
material-dependent.

Answer 21

a. increase.

Question 22

22. The frequency that can best distinguish the difference
    between a large planar discontinuity and four stacked
    (multiple-layered) laminations in rolled plate is:

a. 0.5 MHz
b. 1 MHz
c. 2.25 MHz
d. 5 MHz

Answer 22

d. 5 MHz

Question 23

23. During immersion examination, when evaluating the
    response from a contoured surface of a part,
    irrelevant indications due to the contour are most
    likely to appear as:

a. sharp, spiked signal indications.
b. irregular signal indications.
c. broad-based signal indications.
d. grass or hash.

Answer 23

c. broad-based signal indications.

Question 24

24. The pulse applied to the electrodes of the ultrasonic
    transducer is:

a. electrical.
b. mechanical.
c. electromechanical.
d. piezoelectrical.

Answer 24

a. electrical.

Question 25

25. In calibrating an ultrasonic test instrument using the
    responses from each of the area-amplitude type
    reference blocks, the determination of the:

a. vertical range is obtained.
b. pulse range is obtained.
c. resolving range is obtained.
d. horizontal range is obtained.

Answer 25

a. vertical range is obtained.

Question 26

26. Test sensitivity corrections for metal distance and
    discontinuity area responses are accomplished by
    using:

a. an area-amplitude set of blocks.
b. a distance-amplitude and an area-amplitude set of
blocks.
c. a distance-amplitude set of blocks.
d. steel balls of varying diameter.

Answer 26

b. a distance-amplitude and an area-amplitude set of
blocks.

Question 27

27. The time from the start of the ultrasonic pulse until
    the reverberations completely decay limits the
    maximum usable:

a. pulse time-discontinuity rate.
b. pulser/receiver rate.
c. pulse repetition rate.
d. modified pulse-time rate

Answer 27

c. pulse repetition rate.

Question 28

28. Rough surfaces can cause undesirable effects, which
    are noticeable when parts are tested ultrasonically,
    including:

a. annular maxima rings.
b. an increase in the width of front face echo and
consequent loss of resolving power.
c. acoustical mismatch.
d. asymmetrical modes.

Answer 28

b. an increase in the width of front face echo and
consequent loss of resolving power.

Question 29

29. Rough surfaces cause the echo amplitude from
    discontinuities within the part to:

a. increase.
b. decrease.
c. not change.
d. change frequency.

Answer 29

b. decrease.

Question 30

30. The resonant frequency of a 2 cm (0.79 in.) thick
    plate of naval brass (V = 4.43 × 105 cm/s) is:

a. 0.903 MHz.
b. 0.443 MHz.
c. 0.222 MHz.
d. 0.111 MHz

Answer 30

d. 0.111 MHz

Question 31

31. Resonance testing equipment generally uses:

a. pulsed longitudinal waves.
b. continuous longitudinal waves.
c. pulsed shear waves.
d. continuous shear waves.

Answer 31

b. continuous longitudinal waves.

Question 32

32. To eliminate the decrease of sensitivity close to a wall
    that is parallel to the beam direction, the transducer
    used should be:

a. as small as possible.
b. of as low frequency as possible.
c. large and with a frequency as small as possible.
d. large and with a frequency as high as possible.

Answer 32

d. large and with a frequency as high as possible.

Question 33

33. Which of the following transducer materials makes
    the best transmitter?

a. Quartz.
b. Lithium sulfate.
c. Barium titanate.
d. Lead titanate.

Answer 33

c. Barium titanate.

Question 34

34. Of the transducer materials listed below, the most
    efficient receiver is:

a. quartz.
b. lithium sulfate.
c. barium titanate.
d. lead metaniobate.

Answer 34

b. lithium sulfate.

Question 35

35. The concentration of energy in the far field of a
    transducer beam is:

a. greatest at the outer edges of the beam.
b. greatest at the center of the beam.
c. the same at the outer edges as in the center of the
beam.
d. directly proportional to beam width.

Answer 35

b. greatest at the center of the beam.

Question 36

36. An extensive application of shear waves in ultrasonic
    testing is the inspection of:

a. welds.
b. plate.
c. pipe and tubing.
d. castings.

Answer 36

a. welds.

Question 37

37. In angle beam shear wave testing, skip distance will
    __________ as the thickness of the test specimen is
    increased.

a. decrease
b. not change
c. increase
d. decrease by half with double thickness

Answer 37

c. increase

Question 38

38. The thickness range of UT resonance thickness gages
    can be increased by:

a. using large transducers.
b. operating at the fundamental frequency.
c. operating at a harmonic frequency.
d. increasing the voltage

Answer 38

c. operating at a harmonic frequency.

Question 39

39. The ability of transducers to detect echoes from small
    discontinuities is a definition for:

a. resolution.
b. sensitivity.
c. definition.
d. gain

Answer 39

b. sensitivity.

Question 40

40. The length of the near field for a 2.5 cm (1 in.)
    diameter, 5 MHz transducer placed in oil
    (V = 1.4 × 105 cm/s) is approximately:

a. 0.028 cm (0.01 in.).
b. 6.25 cm (2.5 in.).
c. 22.3 cm (8.8 in.).
d. 55.8 cm (22 in.).

Answer 40

d. 55.8 cm (22 in.).

Question 41

41. From the equation for the length of the near field, it
    can be determined that the near field can be
    minimized by:

a. decreasing water travel distance.
b. increasing transducer diameter.
c. decreasing the size of reference targets.
d. decreasing test frequency.

Answer 41

d. decreasing test frequency.

Question 42

42. In a water (V L = 1.5 × 105
    cm/s) immersion test,
    ultrasonic energy is transmitted into steel (V T = 3.2 ×
    105 cm/s) at an incident angle of 14°. What is the
    refracted shear wave within the material?

a. 13°
b. 35°
c. 31°
d. 53°

Answer 42

c. 31°

Question 43

43. The acoustic impedance for brass (V = 4.43 ×
    105 cm/s, p = 8.42 gm/cm3) is:

a. 0.53 × 10^5 gm/cm^2s
b. 1.9 × 10^5 gm/cm^2s
c. 9.4 × 10^5 gm/cm^2s
d. 37 × 10^5 gm/cm^2s

Answer 43

d. 37 × 105 gm/cm2s

Question 44

44. The principal attributes that determine the
    differences in ultrasonic velocities among materials
    are:

a. frequency and wavelength.
b. thickness and travel time.
c. elasticity and density.
d. chemistry and permeability.

Answer 44

c. elasticity and density.

Question 45

45. What would be the wavelength of the energy in lead
    (V = 2.1 × 105 cm/s) if it is tested with a 25 MHz
    transducer?

a. 119 cm (47 in.)
b. 0.525 cm (0.21 in.)
c. 0.0119 cm (0.005 in.)
d. 0.0084 cm (0.003 in.)

Answer 45

d. 0.0084 cm (0.003 in.)

Question 46

46. What is the transducer half-angle beam spread of a
    1.25 cm diameter, 2.25 MHz transducer in water
    (V = 1.5 × 105 cm/s)?

a. 2.5°
b. 3.75°
c. 37.5°
d. 40.5°

Answer 46

b. 3.75°

Question 47

47. Wavelength may be defined as:

a. frequency divided by velocity.
b. the distance along a wavetrain from peak to
trough.
c. the distance from one point to the next identical
point along the waveform.
d. the distance along a wavetrain from an area of
high particle motion to one of low particle
motion.

Answer 47

c. the distance from one point to the next identical
point along the waveform.

Question 48

48. Velocity measurements in a material revealed that the
    velocity decreased as frequency increased. This
    material is called:
    a. dissipated.
    b. discontinuous.
    c. dispersive.
    d. degenerative.

Answer 48

c. dispersive.

Question 49

49. The sound beam emanating from a continuous wave
    sound source has two zones. These are called the:

a. fresnel and fraunhofer zones.
b. fresnel and near fields.
c. fraunhofer and far fields.
d. focused and unfocused zones.

Answer 49

a. fresnel and fraunhofer zones.

Question 50

50. The difference between through-transmission and
    pitch-catch techniques is that:

a. the transducers in through-transmission face each
other, while in pitch-catch the transducers are
often side by side in the same housing.
b. the transducers in through-transmission are side
by side, while in pitch-catch the transducers are
facing each other.
c. the transducers in
through-transmission are always angle beam.
d. in through-transmission the depth of the
discontinuity is easily determined.

Answer 50

a. the transducers in through-transmission face each
other, while in pitch-catch the transducers are
often side by side in the same housing.