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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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18. The diference between a compression and shear wave is:
- a. quantitative measure
- b. particle direction
- c. qualitative measure
- d. amplitude
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19. The particle motion for Rayleigh waves is usually described as:
- a. sinusoidal
- b. circular
- c. elliptical
- d. shear
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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
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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
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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
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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
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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
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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
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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
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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
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28. The pulse applied to the electrodes of the ultrasonic search unit is:
- a. electrical
- b. mechanical
- c. electro-mechanical
- d. piezoelectrical
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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
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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
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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
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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
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33. Rough surfaces cause the echo amplitude from discontinuities within the part to:
- a. increase
- b. decrease
- c. not change
- d. change frequency
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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
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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
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36. Resonance testing equipment generally utilies:
- a. pulsed longitudinal waves
- b. continuous longitudinal waves
- c. pulsed shear waves
- d. continuous shear waves
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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
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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
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39. Which of the following transducer materials makes the best transmitter?
- a. quartz
- b. lithium sulfate
- c. barium titanate
- d. none of the above
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40. Of the transducer materials listed below, the most efficient receiver is:
- a. quartz
- b. lithium sulfate
- c. barium titanate
- d. lead metaniobate
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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
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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
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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
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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
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45. The ability of transducers to detect echoes from small defects is a definition for:
- a. resolution
- b. sensitivity
- c. definition
- d. gain
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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)
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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
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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
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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
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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)
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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
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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)
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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
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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
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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
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