UT Level III Review Questions Flashcards
- 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.
b. signal amplitude measured using the attenuator
is independent of frequency.
- 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.
a. suppress amplifier noise, unimportant scatter
echoes, or small discontinuity echoes that are of
no consequence.
- 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.
c. nonlinear with respect to the input voltage.
- 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
a. 0.001-1 V
- 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.
b. increase the dynamic range of the instrument.
- 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
b. Perform the examination after a grain-refining
heat treatment.
- 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.
c. acoustic impedance ratio.
- 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.
c. aligned with forging flow lines.
- 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.
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.
- 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.
c. the piezoelectric element should be driven at its
fundamental resonant frequency.
- 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.
a. depends on the transducer, pulser, and amplifier
used.
- 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.
a. depends primarily upon the pulse length
generated from the instrument.
- 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.
b. the amplitude of the response from an artificial
discontinuity.
- 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.
a. distance-amplitude calibration for shear waves.
- 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.
b. inadequate penetration at the root of a weld.
- The difference between a compression and shear
wave is:
a. quantitative measure.
b. relative particle vibration direction.
c. qualitative measure.
d. amplitude.
b. relative particle
- The particle motion for rayleigh waves is usually
described as:
a. sinusoidal.
b. circular.
c. elliptical.
d. shear.
c. elliptical.
- 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.
c. directly proportional to the square of the
diameter of the circular reflector.
- 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.
b. pulser circuit.
- 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.
c. 100-1000 V.
- 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.
a. increase.
- 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
d. 5 MHz
- 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.
c. broad-based signal indications.
- The pulse applied to the electrodes of the ultrasonic
transducer is:
a. electrical.
b. mechanical.
c. electromechanical.
d. piezoelectrical.
a. electrical.
- 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.
a. vertical range is obtained.
- 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.
b. a distance-amplitude and an area-amplitude set of
blocks.
- 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
c. pulse repetition rate.
- 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.
b. an increase in the width of front face echo and
consequent loss of resolving power.
- Rough surfaces cause the echo amplitude from
discontinuities within the part to:
a. increase.
b. decrease.
c. not change.
d. change frequency.
b. decrease.
- 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
d. 0.111 MHz
- Resonance testing equipment generally uses:
a. pulsed longitudinal waves.
b. continuous longitudinal waves.
c. pulsed shear waves.
d. continuous shear waves.
b. continuous longitudinal waves.
- 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.
d. large and with a frequency as high as possible.
- Which of the following transducer materials makes
the best transmitter?
a. Quartz.
b. Lithium sulfate.
c. Barium titanate.
d. Lead titanate.
c. Barium titanate.
- Of the transducer materials listed below, the most
efficient receiver is:
a. quartz.
b. lithium sulfate.
c. barium titanate.
d. lead metaniobate.
b. lithium sulfate.
- 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.
b. greatest at the center of the beam.
- An extensive application of shear waves in ultrasonic
testing is the inspection of:
a. welds.
b. plate.
c. pipe and tubing.
d. castings.
a. welds.
- 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
c. increase
- 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
c. operating at a harmonic frequency.
- The ability of transducers to detect echoes from small
discontinuities is a definition for:
a. resolution.
b. sensitivity.
c. definition.
d. gain
b. sensitivity.
- 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.).
d. 55.8 cm (22 in.).
- 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.
d. decreasing test frequency.
- 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°
c. 31°
- 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
d. 37 × 105 gm/cm2s
- 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.
c. elasticity and density.
- 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.)
d. 0.0084 cm (0.003 in.)
- 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°
b. 3.75°
- 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.
c. the distance from one point to the next identical
point along the waveform.
- 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.
c. dispersive.
- 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.
a. fresnel and fraunhofer zones.
- 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.
a. the transducers in through-transmission face each
other, while in pitch-catch the transducers are
often side by side in the same housing.
