UT Level III Questions2.txt

Card Set Information

UT Level III Questions2.txt
2011-09-24 12:18:40
UT Level III

Home made UT Level III
Show Answers:

  1. 1. In an ultrasonic test system where signal amplitudes are displayed on a CRT, an advantage of a frequency-independent attenuator over a continuously variable gain control is that:
    • a. the pulse shape distortion is less
    • b. the signal amplitude measured using the attenuator is independent of frequency
    • c. the dynamic range of the system is decreased
    • d. the effect of amplification threshold is avoided
  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 flaw echos that are of no
    • consequence
    • b. provide a screen display with nearly ideal vertical linearity characteristics
    • c. compensate for the unavoidable effects of material attenuation losses
    • d. provide distance amplitude correction automatically
  3. 3. The output voltage from a saturated amplifier is:
    • a. 180 degrees out of phase from the input voltage
    • b. lower than the input voltage
    • c. nonlinear with respect to the input voltage
    • d. below saturation
  4. 4. The transmitted pulse at the output of the pulser usually has a voltage of 100 to 1,000V, whereas the voltages of the echoes at the input of the amplifier are on the order of:
    • a. 0.001-1V
    • b. 1-5V
    • c. 10V
    • d. 50V
  5. 5. The intended purpose of the adjustable calibrated attenuator of an ultrasonic instrument is to:
    • a. control tranducer damping
    • b. increase the dynamic range of the instrument
    • c. broaden the frequency range
    • d. attenuate the voltage applied to the transducer
  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 examinantion 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
  7. 7. When material grain size is on the order of ______________ wavelength of larger,excessive scattering of the ultrasonic beam may affect test results.
    • a. 1
    • b. 1/2
    • c. 1/10
    • d. 1/100
  8. 8. In a forging, flaws associated with nonmetllic inclusions can most accurately be described as having which of the following orientations?
    • a. parallel to the major axis
    • b. parallel to the minor axis
    • c. aligned with forging flow lines
    • d. at approximately 45 degrees to the forging direction
  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 ptior to forging
  10. 10. In a long rod that is examined from one end with a longitudinal beam, the most likely effect of longitudinally-oriented discontinuities would be to:
    • a. significantly reduce the back surface reflection
    • b. cause echoes between the initial pulse and the first back surface reflection for which
    • the reflector locations cannot be precisely determined
    • c. remove or reduce the amplitude of echoes from refracted beam paths
    • d. cause excessive baseline noise
  11. 11. 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 band width of the transducer should be as large as possible
  12. 12. Which of the folloing 1 MHz search units should normally have the best time or distance resolution?
    • a. quartz transducer with air backing
    • b. quartz transducer with phenolic backing
    • c. barium titanate transducer with phenolic backing
    • d. lithium sulfate transducer with epoxy backing
  13. 13. The sensitivity of an ultrasonic test system:
    • a. depends on the search unit, 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
  14. 14. The ability of a test system to separate the front-surface echo and the echo from a small discontinuity just below the 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 search unit
  15. 15. Search unit sensitivity is most often determined by:
    • a. calculations based on frequency and thickness of piezoelectric element
    • b. the amplitude of the response from an artificial discontinuity
    • c. comparing it to a similar search unit made by the same manufacturer
    • d. determining the ringing time of search unit
  16. 16. Notches 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
  17. 17. Notches provide good reference discontinuities when UT examination is conducted primarily detect defects such as:
    • a. porosity in a rolled plate
    • b. inadequate penetration at the root of a weld
    • c. weld porosity
    • d. internal inclusions
  18. 18. The diference between a compression and shear wave is:
    • a. quantitative measure
    • b. particle direction
    • c. qualitative measure
    • d. amplitude
  19. 19. The particle motion for Rayleigh waves is usually described as:
    • a. sinusoidal
    • b. circular
    • c. elliptical
    • d. shear
  20. 20. Based upon wave theory and ignoring attenuation losses, the echo amplitude 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 distance to the reflector
    • d. inversely proportional to the square of the distance from the reflector
  21. 21. The rate generator in B-scan equipment will invariably be directly connected to the:
    • a. CRT intensity circuit
    • b. pulser circuit
    • c. RF amplifier circuit
    • d. horizontal sweep circuit
  22. 22. In A-scan equipment, the RF pulser output voltage is normally in the range of:
    • a. 1-10V
    • b. 10-100V
    • c. 100-1,000V
    • d. 1,000-3,000V
  23. 23. 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. cannot be predicted as the response is material-dependent
  24. 24. During the inspection of a parallel-sided, machined forging using the straight beam immersion technique, a diminished back reflection in a localized area in the absence of a defect indication would least likely represent:
    • a. a coarse grain structure
    • b. small nonmetallic stringers
    • c. a defect oriented at a severe angle to the entry surface
    • d. a large inclusion
  25. 25. As you increase the frequency of a given size transducer:
    • a. the lateral resolution is impaired
    • b. the beam divergence increases
    • c. the length of the near field increases
    • d. the sensitivity increases
  26. 26. Which frequency can best distinguish the difference between a large planar defect and 4 stacked (multiple-layered) laminations in rolled plate:
    • a. 0.5 MHz
    • b. 1 MHz
    • c. 2.25 MHz
    • d. 5 MHz
  27. 27. 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. hash
  28. 28. The pulse applied to the electrodes of the ultrasonic search unit is:
    • a. electrical
    • b. mechanical
    • c. electro-mechanical
    • d. piezoelectrical
  29. 29. In calibrating an ultrasonic test instrument utilizing 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
  30. 30. Test sensitivity corrections for metal distance and discontinuity area responses are accomplished by using:
    • a. an area amplitude set of blocks
    • b. an area amplitude and a distance amplitude set of blocks
    • c. a distance amplitude set of blocks
    • d. steel balls of varying diameter
  31. 31. The time from the start of the ultrasonis pulse until the reverberations completely decay limits the maximum ussable:
    • a. pulse time-flaw rate
    • b. pulser/receiver rate
    • c. pulse repetition rate
    • d. modified pulse-time rate
  32. 32. 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
  33. 33. Rough surfaces cause the echo amplitude from discontinuities within the part to:
    • a. increase
    • b. decrease
    • c. not change
    • d. change frequency
  34. 34. When a sound beam travels from a liquid into a metal through a contoured surface, the sound beam inside the metal will:
    • a. have the phase velocities of the first symmetrical and asymmetrical modes
    • b. have the phase velocity of the incident longitudinal wave
    • c. not be affected by the part geometry
    • d. be convergent if the surface is concave, and divergent if the surface is convex
  35. 35. The resonant frequency of a 2cm (0.79in) thick plate of Naval brass (V=4.43 x 10exp5 cm/sec) is:
    • a. 0.903 MHz
    • b. 0.443 MHz
    • c. 0.222 MHz
    • d. 0.111 MHz
  36. 36. Resonance testing equipment generally utilies:
    • a. pulsed longitudinal waves
    • b. continuous longitudinal waves
    • c. pulsed shear waves
    • d. continuous shear waves
  37. 37. To eliminate the decrease of sensitivity close to a wall which is parallel to the beam direction, the probe used should be:
    • a. as small as possible
    • b. of as low frequency as possible
    • c. both a and b
    • d. large and with a frequency as high as possible
  38. 38. Some information on the shape of a flaw may be given by:
    • a. the shape of the echo
    • b. the amplitude of the echo
    • c. both a and b
    • d. neither a nor b
  39. 39. Which of the following transducer materials makes the best transmitter?
    • a. quartz
    • b. lithium sulfate
    • c. barium titanate
    • d. none of the above
  40. 40. Of the transducer materials listed below, the most efficient receiver is:
    • a. quartz
    • b. lithium sulfate
    • c. barium titanate
    • d. lead metaniobate
  41. 41. 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 proprtional to beam width
  42. 42. A typical application of shear waves in ultrasonic testing is the inspection of:
    • a. welds
    • b. plate
    • c. pipe and tubing
    • d. all of the above
  43. 43. 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
  44. 44. 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
  45. 45. The ability of transducers to detect echoes from small defects is a definition for:
    • a. resolution
    • b. sensitivity
    • c. definition
    • d. gain
  46. 46. The length of the near field for a 2.5cm (1in) diameter, 5 MHz transducer placed in oil(V=1.4 x 10exp5 cm/sec) is approximately:
    • a. 0.028cm (0.01in)
    • b. 6.25cm (2.5in)
    • c. 22.3cm (8.8in)
    • d. 55.8cm (22in)
  47. 47. 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
  48. 48. In a water (Vl=1.5 x 10exp5 cm/sec) immersion test, ultrasonic energy is transmitted into steel (Vt=3.2 x 10exp5 cm/sec) at an incident angle of 14 degrees. What is the refracted shear wave within the material?
    • a. 13 degrees
    • b. 35 degrees
    • c. 31 degrees
    • d. 53 degrees
  49. 49. What would be the approximate bandwidth of the transducer with the frequency response shown in Figure 1 (-3 dB)?
    • a. 4 MHz
    • b. 8 MHz
    • c. 10 MHz
    • d. 12 MHz
  50. 50. The acoustic impedance for brass (V=4.43 x 10exp5 cm/sec, p=8.42 gm/(cm cubed)) is:
    • a. 0.53x10exp5 gm/cm(squared)
    • b. 1.9x10exp5 gm/cm(squared)
    • c. 9.4x10exp5 gm/cm(squared)
    • d. 37x10exp5 gm/cm(squared)
  51. 51. The principal attributes that determine the differences in ultrasonic velocities among materials are:
    • a. frequency and wavelength
    • b. thickness and travel time
    • c. elastic and density
    • d. chemistry and permeability
  52. 52. What would be the wavelength of the energy in lead (V=2.1x10exp5 cm/sec) if it is tested with a 25 MHz transsducer?
    • a. 119cm (47in)
    • b. 0.525cm (0.21in)
    • c. 0.0119cm (0.005in)
    • d. 0.0084cm (0.003in)
  53. 53. What is the transducer half-angle beam spread of a 1.25cm diameter, 2.25 MHz transducer in water (V=1.5x10exp5 cm/sec)?
    • a. 2.5 degrees
    • b. 3.75 degrees
    • c. 37.5 degrees
    • d. 40.5 degrees
  54. 54. 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
  55. 55. In general, when a discontinuity is thin it is a poor reflector. The maximum reflection is obtained when the thickness of the discontinuity is equal to at least:
    • a. 1/4 wavelength
    • b. 1/2 wavelength
    • c. 1 wavelength
    • d. even multiples of 1/2 wavelength