Q/a Flashcards
Which of the following circuits provides short duration, high energy pulses which are used to excite the transducer?
(a) The pulse generator
(b) The amplifier
(c) The transducer
(d) The clock
A. the pulse generator
Which of the following circuits provide current to OPERATE the ultrasonic instrument?
(a) The pulse generator
(b) The amplifier
(c) The power supply
(d) The sweep generator
C. Power supply
The longitudinal wave incident angle at which the refracted shear wave angle equals ninety degrees is called:
(a) The Snell angle
(b) The Snell constant
(c) The first critical angle
(d) The second critical angle
D. Second critical angle
In immersion testing, the position of the search unit is often varied to transmit sound into the test part at various angles to the front surface. Such a procedure is referred to as:
(a) Angulation
(b) Dispersion
(c) Reflection testing
(d) Refraction
A. Angulation
The angle of a refracted shear wave generated as a sound wave passes at an angle through an acoustic interface is dependant on:
(a) The acoustic impedances of the materials of each side of the interface
(b) The frequency of the incident sound wave
(c) The wavelength of the incident sound wave
(d) The hardness of the materials on each side of the interface
A. The acoustic impedances of the materials of each side of the interface
An ultrasonic instrument control which allows moving an A scan display to the LEFT or RIGHT WITHOUT CHANGING THE DISTANCE between any echoes displayed is called:
(a) The sweep length or range control
(b) The damping control
(c) The sweep delay
(d) The pulse length control
C. Sweep delay
A more highly damped transducer crystal results in:
(a) Better resolution
(b) Better sensitivity
(c) Lower sensitivity
(d) Poorer resolution
A. Better resolution
Scattering of an ultrasonic beam is most pronounced when:
(a) Material grain size and wavelength are comparable
(b) Low frequency transducers are used
(c) Large wavelengths are used for ultrasonic testing
(d) None of the above
A. Material grain size and wavelength are comparable
Which technique would most likely be used to examine a weld, with the weld cap still in place?
(a) Through transmission testing
(b) Angle beam testing
(c) Straight beam testing
(d) None of the above
B. Angle beam testing
The maximum frequency usually used for contact testing is: (a) 1 MHz
(b) 5 MHz
(c) 10 MHz
(d) 25 MHz
B. 5MHz
Typical ultrasonic testing frequencies are:
(a) 50 kHz to 1 MHz
(b) 200 kHz to 25 MHz
(c) 10 MHz to 100 MHz
(d) 1MHzto5MHz
D. 1MHz to 5MHz
A disadvantage of using a high frequency ultrasonic transducer is:
(a) It provides a smaller beam angle and better resolving power
(b) It provides a larger beam angle and poorer resolving power
(c) It is scattered more by coarse grained material
(d) It is scattered less by coarse grained material
C. It is scattered more by coarse grained material
Which of the following circuits provides timing signals to the pulser?
(a) The clock
(b) The amplifier
(c) The pulse generator
(d) The sweep generator
A. The clock
With longitudinal wave incident at angles between the first and second critical angles:
(a) The sound beam is totally reflected
(b) Only shear waves are produced in the second material
(c) Shear waves and longitudinal waves are produced in the second material
(d) Only longitudinal waves are produced in the second material
Only shear waves are produced in the second material
An ultrasonic wave in which particle displacement is 90 degrees to the direction of wave propagation is called a:
(a) Longitudinal wave
(b) Shear wave
(c) Compressional wave
(d) Plate wave
B. Shear wave
An ultrasonic instrument control which is used to expand or contract the horizontal base line of an A scan display is called:
(a) The sweep length or range control
(b) The damping control
(c) The sweep delay
(d) The pulse length control
A. The sweep length or range control
The speed of sound in a given material depends on:
(a) The specific acoustic impedance of the material
(b) The acoustic impedance and density of the material
(c) The density and elasticity of the material
(d) The piezo-electric resistance of the material
C. The density and elasticity of the material
The first critical angle is defined as the longitudinal wave incident angle which results in:
(a) A refracted longitudinal wave of ninety degrees
(b) A refracted shear wave of ninety degrees
(c) Complete reflection of the shear wave
(d) None of the above
A. A refracted longitudinal wave of ninety degrees
The portion of a test piece which is represented by the CRT screen area from zero to the rightmost edge of the initial pulse is called:
(a) The dead zone
(b) The near field
(c) The near zone
(d) The far zone
B. The near field
Spurious indications might be caused by which of the following?
(a) Mode conversion from beam spread in a long specimen
(b) Surface waves generated during straight beam testing
(c) A test piece with a smooth machined surface
(d) All of the above
A. Mode conversion from beam spread in a long specimen
An ultrasonic test using a straight beam contact search unit is being conducted through the thickness of a flat part such as a plate. This test should detect:
(a) Laminar-type flaws with major dimensions parallel to the rolled surface
(b) Transverse-type flaws with major dimensions at right angles to the rolled surface
(c) Radial flaws with major dimensions along length but radially oriented to the rolled surface
(d) None of the above
A. Laminar-type flaws with major dimensions parallel to the rolled surface
Transducer focal lengths are normally specified as:
(a) Distance in steel
(b) Distance in aluminium
(c) Distance in air
(d) Distance in water
A. Distance in steel
Spurious or nonrelevant indications might be suspected if:
(a) Indications are unusually consistent in amplitude and appearance
(b) There are strong indications in localised areas
(c) The indications are localised and repeatable
(d) None of the above
(a) Indications are unusually consistent in amplitude and appearance
A disadvantage of lithium sulfate as a transducer material is that:
(a) It is an inefficient receiver of ultrasonic energy
(b) It is soluble in water
(c) It is not piezo- electric
(d) It has extremely coarse grain structure
B. It is soluble in water
A larger diameter crystal results in:
(a) Greater beam spread
(b) Lower penetrating power
(c) Less beam spread
(d) Greater penetrating power
C. Less beam spread
Entry surface resolution is a characteristic of an ultrasonic testing system which defines its ability to:
(a) Detect discontinuities oriented in a direction parallel to the ultrasonic beam
(b) Detect discontinuities located in the center of a forging containing a fine metallurgical structure
(c) Detect minute surface scratches
(d) Detect discontinuities located just beneath the entry surface in the part being tested
D. Detect discontinuities located just beneath the entry surface in the part being tested
In immersion testing, verification that the search unit is normal to a flat entry surface is indicated by:
(a) Maximum reflection from the entry surface
(b) Proper wavelength
(c) Maximum amplitude of the initial pulse
(d) Elimination of water multiples
A. Maximum reflection from the entry surface
The most useful range of incident longitudinal wave angles for ultrasonic testing is:
(a) Normal incidence to the first critical angle
(b) First critical angle to the second critical angle
(c) Second critical angle to the third critical angle
(d) Above the third critical angle
A. Normal incidence to the first critical angle
A standard block which can be used to calibrate an instrument for an angle beam range calibration is:
(a) Area-amplitude blocks
(b) Distance-amplitude blocks
(c) V1/A2 block
(d) Beam spread block
C. V1/A2 block
A disadvantage of using a low frequency ultrasonic transducer is:
(a) It provides better penetration in most materials
(b) It provides poorer penetration in most materials
(c) It provides a smaller beam angle and poorer resolving power
(d) It provides a larger beam angle and poorer resolving power
C. It provides a smaller beam angle and poorer resolving power
A widening of the front surface indication, when testing a rough surface, is caused by:
(a) Defects in the test piece
(b) A coarse grain structure
(c) A partial reflection of ultrasonic beam side lobe energy
(d) Ultrasonic instrument malfunction
C. A partial reflection of ultrasonic beam side lobe energy
Piezoelectric ability is the property of a material to:
(a) Become electrically conductive when heated above its critical temperature (b) Generate sound when heated above its critical temperature
(c) Vibrate at high frequency when subjected to a temperature gradient
(d) Produce an electric current when deformed and vice versa
D. Produce an electric current when deformed and vice versa
An ultrasonic insrument control which is used to adjust the sharpness of the CRT screen display is called:
(a) Astigmatism or focus
(b) Pulse repetition rate
(c) Pulse energy
(d) Gain
A. Astigmatism or focus
Bubblers and wheel transducers are considered:
(a) Immersion techniques
(b) Modified immersion techniques
(c) Contact techniques
(d) Offset techniques
B. Modified immersion techniques
On the area-amplitude ultrasonic standard test blocks, the flat-bottomed holes in the blocks are:
(a) All of the same diameter
(b) Different in diameter, increasing by 1/64 inch increments from the No. 1 block to the No. 8 block
(c) Largest in the No. 1 block and smallest in the No. 8 block
(d) Drilled to different depths from the front surface of the test block
B. Different in diameter, increasing by 1/64 inch increments from the No. 1 block to the No. 8 block
An ultrasonic instrument control which is used to EXPAND OR CONTRACT the horizontal base line of an A scan display is called:
(a) The sweep length or range control
(b) The damping control
(c) The sweep delay
(d) The pulse length control
A. The sweep length or range control
Sound beam intensity decreases expontentially with distance in the area called:
(a) The near field
(b) The far field
(c) The dead zone
(d) The delay line
B. Far field
A display which shows the initial pulse and the front surface echo superimposed would be considered:
(a) An immersion test
(b) An A scan
(c) A contact test
(d) A B scan
B. An A scan
A display which shows the initial pulse and the front surface echo with a fairly wide space between the two would be considered:
(a) An immersion test
(b) An A scan
(c) A contact test
(d) A B scan
A. Immersion test
When conducting an immersion test, the water path distance must be controlled so that:
(a) Spurious signals are not created by surface waves on the test piece
(b) The (water path distance)/(diameter) ratio does not result in asymmetric standing waves
(c) The test piece discontinuity indications appear between the first front and first back surface echos
(d) The second front surface echo does not appear on the CRT screen between the first front and first back surface echos
C. The test piece discontinuity indications appear between the first front and first back surface echos
PHASE REVERSAL of an ultrasound wave upon reflection from a sonically softer material is indicated by
A) a zero R value
B) a negative R value
C) an R value greater than 1
D) increased resonance
B. a negative R value
In determining the coefficient of reflection, a negative value indicates
A) reduced amplitude
B) loss of sound pressure
C) phase reversal relative to the incident wave
D) none of the above
C. phase reversal relative to the incident wave
2,500,000 cycles per second (cps) is also expressed as
A) 25 kHz
B) 2.5 MHz
C) 2.5 mHz
D) 25 GHz
B. 2.5MHz
The point where MAXIMUM PARTICLE DISPLACEMENT occurs on a standing wave is called
A) an anticline
B) an antinode
C) a node
D) a peak detector
B. an antinode
The point where no particle displacement occurs on a standing wave is called
A) an anticline
B) an antinode
C) a node
D) a dead zone
C. a node
Surface waves limited on two surfaces are also called
A) long. waves
B) lamb waves
C) shear waves
D) P waves
B. lamb waves
The maximum displacement of a particle from its point of rest in a sound wave is its
A) velocity
B) amplitude of movement
C) frequency
D) wavelength
B. amplitude of movement
The smallest distance between two points on an elastic wave where the particles are in the same state of motion is the
A) period
B) wavelength
C) frequency
D) hypotenuse
B. wavelength
If a sound beam is incident on steel from water at 20 degrees, the refracted transverse wave will have an angle
A) greater than 20 degrees
B) less than 20 degrees
C) about 20 degrees
D) that cannot be determined
A. greater than 20 degrees
The incident angle at which the transmitted longitudinal wave first ceases to exist in the diffracting medium is called the
A) longitudinal angle
B) short angle
C) first critical angle
D) second critical angle
C) first critical angle
The incident angle at which the transmitted longitudinal wave first ceases to exist in the diffracting medium is called the
A) longitudinal angle
B) short angle
C) first critical angle
D) second critical angle
C. first critical angle
The incident angle at which the transmitted transverse wave first ceases to exist in the refracting medium is called the
A) long angle
B) short angle
C) first critical angle
D) second critical angle
D. second critical angle
If a sound beam is incident on steel from water at 20 degrees, the refracted transverse wave will have an angle
A) greater than 20 degrees
B) less than 20 degrees
C) about 20 degrees
D) that cannot be determined
A. greater than 20 degrees
For a longitudinal wave entering a medium of lower acoustic velocity, the refracted longitudinal wave angle in the new material will be
A) totally internally reflected
B) the same
C) less than incidence angle
D) greater than incidence angle
C. less than incidence angle
According to geometric-optic treatment of sound, acoustic pressure
A) increases with distance from source
B) decreases with distance from source
C) varies unpredictably with distance from source
D) none of the above
B. decreases with distance from source
In practical ultrasonic testing, mirror surfaces can be used with sound beams to
A) image flaws
B) reach points of difficult access
C) reduce scatter
D) reduce short wave dispersion effects
B. reach points of difficult access
For a longitudinal wave entering a medium of lower acoustic velocity, the REFRACTED LONGITUDINAL wave angle in the new material will be
A) totally internally reflected
B) the same
C) less than incidence angle
D) greater than incidence angle
C. less than incidence angle
Acoustic pressure fluctuates in the near zone due to
A) diffraction interference
B) dispersion
C) refraction
D) density fluctuations
A) diffraction interference
In practical ultrasonic testing, mirror surfaces can be used with sound beams to
A) image flaws
B) reach points of difficult access
C) reduce scatter
D) reduce short wave dispersion effects
B. reach points of difficult access
The interference pattern produced in front of a transducer face is a result of
A) rarefaction
B) dispersion
C) diffraction
D) refraction
C. diffraction
The distance from the probe face to the last main maximum on the beam axis is called the
A) near field
B) far field
C) dead zone
D) ozone
A. near field
Acoustic pressure fluctuates in the near zone due to
A) diffraction interference
B) dispersion
C) refraction
D) density fluctuations
A. diffraction interference
A longitudinal wave generating transducer will have a given near field in steel. If in water the near field for this probe will be
A) the same distance
B) about half as long
C) about 1/4 as long
D) about 4 times as long
D. 4x as long
Acoustic pressure along the beam axis moving away from the probe has various maxima and minima due to interference. At the end of the near field pressure is
A) a maximum
B) a minimum
C) the average of all maxima and minima
D) none of the above
A. a maximum
Variations in acoustic pressure at right angles to the probes’ sound beam in the near zone are a result of
A) side lobes
B) overtones
C) sub harmonics
D) divergence
A. side lobes
The angle of divergence is:
A) constant for a given piezoelectric material
B) applicable to the far zone only
C) increases with increasing probe dimensions
D) decreases with increasing wavelength
B. applicable to the far zone only
The “main lobe” of a rectangular probe is
A) axially symmetric
B) broader in the small probe dimension
C) narrower in the small probe dimension
D) two dimensional
B. broader in the small probe dimension
Focusing of ultrasound is accomplished by
A) curved piezoelectric crystals
B) lenses
C) both a and b
D) none of the above
C. both a and b
AVG (or DGS in English) diagrams are used for
A) establishing gain settings
B) determining vertical beam spreads
C) estimating flaw size
D) none of the above
C. estimating flaw size
Flaw detection using the through transmission method can give accurate information about
A) flaw depth
B) flaw type
C) flaw orientation
D) none of the above
D. none of the above
Flaw detection using the through transmission method can give accurate information about
A) flaw depth
B) flaw type
C) flaw orientation
D) none of the above
D. None of the above
In ultrasonic testing, a wave pulse contains
A) a single well defined frequency
B) a range of frequencies
C) two full cycles
D) only positive going waves
B. a range of frequencies
The main contribution to loss of sound pressure of a beam incident on a rough surface is provided by
A) scatter
B) mode conversion
C) refraction
D) diffraction
A. Scatter
For best results detecting a defect that may be irregularly shaped and slightly off perpendicular to the beam, the wavelength used should be
A) the size of the defect
B) as small as possible
C) as large as possible to locate the defect
D) 1 MHz
C. as large as possible to locate the defect
In ultrasonic testing by pulse-echo method, the sound waves off the probe are
A) omni-directional
B) a single frequency
C) a range of frequencies
D) non-existent in the dead zone
C. a range of frequencies
Attenuation of ultrasound by absorption is a result of
A) reflection
B) refraction
C) scatter
D) heating
D. heating
For a plane wave, sound pressure is reduced by attenuation in a(n) _______ fashion.
A) linear
B) exponential
C) random
D) none of the above
B. exponential
If a signal on your CRT is 28% FSH and 6 dB gain is added to the receiver amplifier the signal will be _______ FSH.
A) 34%
B) 42%
C) 56%
D) 70%
C. 56%
If a signal is reduced from 84% to 42% FSH, the number of dB gain removed from the receiver is
A) 2
B) 6
C) 12
D) 42
B. 6
A typical maximum thickness range for inspecting forged steel by ultrasonics is
A) 0.5 to 1m
B) 1 to 2 m
C) 1 to 10 m
D) 10 to 100 m
C. 1 to 10m
As temperature of a solid increases the attenuation of sound in that object tend to
A) increase
B) decrease
C) remain constant
D) vary sinusoidally
A. increases
Scatter of ultrasound at grain boundaries is a result of
A) frequency
B) in-homogenous inclusions
C) angulation
D) differences in elastic properties
D. differences in elastic properties
Scatter generally increases with
A) increasing grain size
B) decreasing wavelength
C) increasing frequency
D) all of the above
D. all the above
The piezoelectric material first used for ultrasonic transducers is
A) PZT
B) SiO2 (quartz)
C) Na Cl
D) PVDF
B. SiO2 (quartz)
X-cut quartz crystal transducers are cut with active element face at right angles to the
A) X-axis
B) Y1-axis
C) Y2-axis
D) Z-axis
A. X-axis
Shifts of the positive charge on the silicon and negative charge on the oxygen in a quartz crystals account for
A) twin crystals
B) the piezoelectric effect
C) polymorphs
D) none of the above
B. the piezoelectric effect
Applied voltage on a piezoelectric crystal used in a transducer requires ________ to cause mechanical displacement
A) electrodes
B) vibration
C) heat
D) all of the above
A. electrodes
The fundamental frequency of a piezoelectric crystal used in ultrasonics is a function of
A) its thickness
B) the velocity of sound in the crystal material
C) both a and b
D) none of the above
C. both a and b
The ratio of vibration amplitude at resonance frequency to the amplitude of static thickness change is called
A) fo
B) fr
C) the modulus of resonance
D) Q factor
D. Q factor
A large Q factor indicates
A) high damping
B) narrow bandwidth
C) wide bandwidth
D) low permeability
B. narrow bandwidth
Resonance peaks at frequencies of odd numbered multiples of the resonance frequency are called
A) harmonics
B) PRF
C) multiple frequencies
D) sub-harmonics
A. harmonics
In pulse-echo testing there is an advantage to using short pulses to excite the transducer because
A) the dead zone is decreased
B) the frequency spectrum is broadened
C) both a and b
D) none of the above
C. both a and b
Of the various materials used for transducer crystals, lithium sulphate hydrate is the most critical because it
A) looses its water of crystallization above 130 degrees C
B) breaks down at excitation voltages over 500 V
C) cannot be used in immersion testing
D) all of the above
A. looses its water of crystallization above 130 degrees C
A PZT transducer will loose its piezoelectric property if
A) immersed in water
B) used on a forging that has not been de-magnetized
C) used on a surface whose temperature is 140 degrees C
D) heated above its curie point
D. heated above its curie point
In addition to a low critical temperature, lithium sulphate hydrate
A) is soluble in water so must be water proofed
B) is a poor impedance match to water
C) has the lowest coupling coefficient
D) none of the above
A. is soluble in water so must be water proofed
Methods of generating and receiving ultrasound by deformation of ferromagnetic materials in a magnetic field utilize the phenomenon called
A) magnetics
B) electrodynamics
C) magnetostriction
D) eddy currents
C. magnetostriction
Magnetostrictive principles can be used
A) for transmitting ultrasound
B) for receiving ultrasound
C) both a and b
D) none of the above
C. both a and b
Mechanical methods of ultrasound generation
A) utilise electro-mechanical hammers
B) utilise rotating wire brushes
C) require no coupling liquids
D) all of the above
D. All the above
The method whereby sound is transmitted through a plate from a transmitter on one side to a receiver on the other
A) is used to characterize flaws
B) is called an intensity method
C) is used to determine flaw depth
D) all of the above
B. is called an intensity method
Using the pulse echo method with a 0 degrees probe (single crystal) on a flat steel plate 50mm thick, the pattern on the CRT would appear as
A) evenly spaced multiples
B) randomly spaced multiples
C) multiples with increasing spacing between them
D) none of the above
A. evenly spaced multiples
When testing thick specimens, it may be advisable to
A) decrease the pulse repetition frequency
B) add reject
C) change to a higher frequency
D) use a delay line probe
A. decrease the pulse repetition frequency
In immersion testing you would normally position the
A) main bang on the left edge of the CRT
B) entrance echo on the left edge graticule of the CRT
C) first backwall on the right edge of the CRT
D) none of the above
B. entrance echo on the left edge graticule of the CRT
Transmitter VOLTAGE pulse is triggered by the
A) probe resonance
B) control pulse of the sweep generator
C) sweep delay control
D) vertical deflector plates in the CRT
B. control pulse of the sweep generator
For flaws immediately below the surface the best option is
A) TR or twin crystal probes
B) single crystal probes
C) multi probe configurations
D) through wall testing
A. TR or twin crystal probes
The normal presentation of ultrasonic signals on an ultrasonic machine used in NDT is
A) rectified form
B) RF form
C) B-scan
D) C-scan
A. rectified form
If not equipped with a frequency selector for the receiver amplifier an ultrasonic machine would probably use a (an)
A) broadband receiver
B) wide receiver
C) ineligible receiver
D) tight end
A. broadband receiver
Threshold adjustment is applied to
A) RF display of signals
B) “clean up” the noise on the baseline
C) both a and b
D) none of the above
B. “clean up” the noise on the baseline
Electrode material on the piezoelectric crystal faces, typically evaporated to about 1000 angstroms thick, is made of
A) gold
B) silver
C) chrome/gold
D) all of the above can be used
D. All the above
Boron, aluminum oxide and sapphire are often used in transducers as
A) tuning transformers
B) electrodes
C) wear faces
D) none of the above
C. wear faces
In contact testing using angle beam probes with removable wedges, the purpose of grooves in the front of the wedge is:
A) to prevent couplant buildup
contact testing using angle beam probes with removable wedges, the purpose of groves in the front
B) increase resolution
C) absorb internally reflected sound
D) all of the above
C. absorb internally reflected sound
Unless otherwise noted, the refracted beam angle on a perspex wedge is the refracted angle in
A) aluminum
B) brass
C) plastic
D) steel
D. Steel
Angle beam wedges can be used to generate surface waves only if
A) the refracted shear wave is 90°
B) the test piece is steel
C) the test piece is cylindrically shaped
D) none of the above
A. the refracted shear wave is 90°
A property of the receiver amplifier that is periodically verified is
A) horizontal linearity
B) vertical linearity
C) beam spread
D) near zone
B. vertical linearity
Information obtained about the exit point and refracted angle of an angle beam probe
A) is qualitative only
B) must be checked periodically since the probe is subject to wear
C) is fixed by the manufacture
D) none of the above
B. must be checked periodically since the probe is subject to wear
Resonance testing methods are used for
A) determining Poisson’s ratio
B) flaw detection
C) thickness testing
D) all of the above
C. Thickness testing
When inspecting a thin flat plate with a 60ø shear wave probe it is possible to see both top and bottom corners of the plate when the beam is aimed at the plate edge. This is due to
A) ghosting
B) splitting
C) beam spread
D) none of the above
C. beam spread
In plate testing with angle beams, the full skip distance refers to
A) the sound path to the opposite wall
B) twice the sound path to the opposite wall
C) the plate thickness
D) twice the plate thickness
B. twice the sound path to the opposite wall
For an ultrasound beam to skip in the circumferential direction of a tubular product
A) the ratio of inside to outside diameter must be right
B) the incident angle must be sufficiently steep
C) both a and b
D) none of the above
C. both a and b
Surface wave ultrasonic testing is superior to penetrant testing because it
A) is cheaper
B) is faster
C) can find sub-surface defects
D) can be used on ferro-magnetic materials
C. can find sub-surface defects
If the sound beam strikes a flaw at right angles and the flaw has a greater area than the beam it will
A) cause resonance
B) absorb most of the beam energy
C) cause destructive interference
D) act like a back wall
D. act like a back wall
Although INGOTS of metal are often difficult to test by ultrasonics due to large dimensions and scatter due to grain size, it is USEFUL TO LOCATE
A) laminations
B) bursts
C) gross piping
D) cold shots
C. gross piping
Which of the following plate defects would not be a result of inservice use?
A) stress-corrosion cracking
B) laminations
C) fatigue cracking
D) pitting
B. laminations
Production line testing of high pressure ribbed tubing would use which ultrasonic technique?
A) contact testing
B) immersion testing from the outside diameter
C) immersion testing from the inside diameter
D) the bubbler technique
C. immersion testing from the inside diameter
The 3 essential elements common to all systems that use ultrasonic devices are
A) transducers, cables, couplant
B) transducers, scopes, testpiece
C) power source, transducer, converter
D) none of the above
C. power source, transducer, converter
The number of nanoseconds in 2 milliseconds is
A) 0.002
B) 2000
C) 2 X 10^6
D) 2 X 10^9
C. 2 X 10^6
When a piezoelectric material has a voltage applied to it
A) eddy currents are generated
B) flux leakage can be used for testing
C) mechanical deformation occurs
D) all of the above
C. mechanical deformation occurs
To a degree, the mechanical deformation of a piezoelectric material is directly proportional to the
A) acoustic impedance of the backing
B) acoustic impedance of the piezo material
C) applied voltage
D) none of the above
C. applied voltage
So as to be utilized as ultrasonic transducers, ferroelectric ceramics must
A) be heated above their curie point
B) poled
C) be put into an electric field
D) all of the above
D. all the above
Most piezoelectric ceramics (ferroelectrics) are
A) polycrystalline
B) also ferromagnetic
C) statically charged
D) are better receivers than transmitters
A. polycrystalline
When ferro electric ceramics such as PZT are heated to above their curie point and held under a bias voltage while cooling to 80øC they are considered
A) neutralized
B) annealed
C) poled or polarized
D) charged
C. poled or polarized
The advantage of quartz crystals over ceramic materials for ultrasonic transducers is
A) high curie temperature
B) its hardness and ability to take a high polish
C) both a and b
D) there are no advantages of quartz over ceramics
C. both a and b
Although quartz has about twice the receiving sensitivity of PZT, PZT used for pulse-echo testing in NDT results in higher amplitude signals for the same conditions because
A) transmission constant is higher
B) PZT dielectric constant is lower
C) PZT has a lower density
D) all of the above
A. transmission constant is higher
A positive valve of a reflection coefficient indicates
A) no phase change has occurred
B) 90 degree phase change
C) 180 degree phase change
D) an increase in amplitude
A. no phase change has occured
A negative value of a reflection coefficient indicates
A) no phase change has occurred
B) 90° phase change
C) 180° phase change
D) a decrease in amplitude
C. 180° phase change
The purpose of highly absorptive backing material in transducers used for testing is to
A) eliminate sound re-entering the crystal
B) maximize rise time
C) maximize fall time
D) obtain highest resolution by broadening the frequency bandwidth
A. eliminate sound re-entering the crystal
Short highly damped pulses of ultrasound have their advantage in NDT in that
A) sensitivity is increased
B) time measurement accuracy is improved
C) defect characterizations is simplified
D) all of the above
B. time measurement accuracy is improved
A material that exhibits dimensional changes in a magnetic field is said to be A) electrostrictive
B) ferroelectric
C) magnetostrictive
D) electromagnetic
C. magnetostrictive
Standing waves in any medium are result of
A) interference from reflections
B) the PRF
C) wave splitting
D) mode conversion at boundaries
A. interference from reflections
An acoustic lens for focusing ultrasound at a specific point in front of the transducer is made as thin as possible so as to
A) make the probe as light as possible
B) obtain the shortest focal length
C) minimize absorption
D) all of the above
C. minimize absorption
The purpose applying ultrasound to a weld puddle during electric arc welding is to
A) prevent lack of penetration
B) increase heat in the weld puddle
C) create a finer grain structure and increase tensile strength
D) eliminate the requirement for radiographic testing
C. create a finer grain structure and increase tensile strength
Focusing of ultrasound energy is accomplished by
A) lenses
B) shaping ceramic transducers
C) test piece geometry
D) all of the above
D. all the above
Ultrasonics used for DRILLING or MACHINING has the advantage that
A) no cutting fluids are required
B) complex shapes can be cut out in a single pass
C) the workpiece does not heat up locally
D) all of the above
B. complex shapes can be cut out in a single pass
Using the through transmission method of ultrasonic testing
A) no couplant is needed
B) no flaw echo is seen
C) only one transducer is used
D) fillet welds are best tested
B. no flaw echo is seen
The advantage of a longer path length in the standard perspex wedge of a common contact-angle beam transducer is
A) improved near surface resolution
B) better impedance matching
C) higher sensitivity to small defects
D) all of the above
A. improved near surface resolution
Increased damping on a piezoelectric element results in
A) reduced ringing time
B) increased resolution
C) decreased sensitivity
D) all of the above
D. all the above
The difference between a thickness gauge and a distance gauge is
A) the range that is measured
B) velocities involved
C) type of piezoelements used
D) all of the above
A. the range that is measured
The incremental fine gain control of the ultrasonic instrument is calibrated in
A) 1 or 2 dB increments
B) 6 dB increments
C) 20 dB increments
D) no increments, it is completely variable
A. 1 or 2 dB increments
“Delay” on the ultrasonic machine is used to
A) reduce grass level
B) compensate for range errors
C) correct for proper zero point
D) adjust lag on the pulser
C. correct for proper zero point
Most codes would recommend the actual beam angle of an angle beam probe not deviate from the indicated angle by more than
A) one half degree
B) one degree
C) two degrees
D) five degrees
C. 2 degrees
The best way to determine the required sensitivity for ultrasonic testing is
A) to use 20 dB over the gain needed to put the 1.5 mm diameter hole of the IIW block to 80% FSH
B) use enough gain to get “10% grass” from the opposite wall
C) use reference welds with real defects of the minimum acceptable size
D) from flat bottom hole and side drilled hole response studies
C. use reference welds with real defects of the minimum acceptable size
Attenuation is not a result of
A) beam geometry
B) scatter
C) bond breaking at the molecular level
D) absorption
A. beam geometry
When using angle beams (transverse waves) for ultrasonic testing, the position of a flaw signal on the timebase can be calibrated for
A) sound path length
B) stand-off distance
C) depth of defect
D) all of the above
D. all of the above
The gain required to compensate for differences in coupling efficiency between a reference or calibration block and the work piece is called
A) transfer correction or transfer value
B) absorption coefficient C) scatter modulus
D) attenuation constant
A. transfer correction or transfer value
In weld inspection, transverse cracks are best located by
A) scanning at right angles to the weld axis
B) scanning parallel to the weld axis
C) the lamination scan
D) immersion testing
B. scanning parallel to the weld axis
The recommended refracted angle for contact shear wave inspection of plate less than 10mm thick is
A) 45
B) 60°
C) 70°
D) all of the above
C. 70°
The length of a defect is calculated from
A) DGS diagrams
B) lateral probe movement
C) amplitude
D) horizontal displacement of the signal on the timebase
B. lateral probe movement
Maximum amplitude response of a planar defect will usually be had when
A) its main surface is perpendicular to the sound beam
B) its main surface is parallel to the sound beam
C) its main surface is oblique to the sound beam
D) none of the above, amplitude will be about equal for a given flaw regardless of orientation
A. its main surface is perpendicular to the sound beam
Reference reflectors in calibration blocks are normally cylindrical holes because
A) they are easier to machine
B) they best represent actual defects
C) they are not as directionally dependant
D) none of the above
C. they are not as directionally dependant
If the beam from an unfocused probe strikes a convex steel surface from water with normal incidence it will
A) increase beam spread
B) decrease beam spread
C) focus the beam
D) none of the above
A. increase beam spread
If the beam from an unfocused probe strikes a CONVEX steel surface from water with normal incidence it will
A) increase beam spread
B) decrease beam spread
C) focus the beam
D) none of the above
A. increase beam spread
If the beam from an unfocused probe strikes a CONCAVE steel surface with normal incidence from water it will
A. increase beam width
B. decrease beam width
C. be totally converted to surface waves
D. none of the above
B. decrease the beam width
The effect of increasing the temperature of a test piece to 30 degrees C. is to
A) improve acoustic coupling
B) decrease resolution
C) require high temperature couplant
D) decrease acoustic velocity
D. decrease acoustic velocity
When using the IIW Block #1, the probe exit point is established using the
A) 1.5mm diameter hole
B) 100mm radius
C) 50mm diameter hole
D) perspex insert
B. 100mm radius
When calibrating for an inspection range of 0 to 100mm with an angle beam probe, delay on the instrument must be
A) increased
B) decreased
C) left untouched
D) adjusted to correct for the time delay in the perspex wedge
D. adjusted to correct for the time delay in the perspex wedge
The main advantage of the V2 or DIN block (IIW block 2) is
A) increased number of characteristics that can be tested
B) greater ranges can be tested
C) improved sensitivity calibrations
D) portability
D. portability
When using the large IIW Block #1, what are the fewest number of reflections from the 100mm radius in order to calibrate a 70 degree shear wave probe for a 100mm range?
A) 1
B) 2
C) 2 1/2
D) 3
B. 2
The use of flat bottom holes for a reference standard when testing forgings is a reasonable method of flaw assessment because
A) they provide good reflectivity at all angles
B) of their ease of manufacturing
C) a single block is required for all calibrations
D) they are a good representation of the flat defects found in forgings
D. they are a good representation of the flat defects found in forgings
Attenuation of ultrasonic energy is an inherent property of all materials and is
A) a constant 0.5 dB/cm
B) variable with alloy (density) and test frequency
C) a function of acoustic impedance
D) both b and c
B. variable with alloy and test frequency
The main contribution of sound attenutation of a beam incident on a rough surface
A. sound dispersion
B. mode conversion
C. refraction
D. diffraction
A. sound dispersion
The primary purpose of reference blocks is to:
A. Aid operator in obtaining max back reflections
B. Obtain greatest sensitivity possible from an instrument
C. Obtain a common reproducible signal
D. Properly tune the transducer
C. Obtain a common reproducible signal
During ultrasonic testing by immersion method it is frequently necessary to angulate the transducer when a discontinuity is located in order to:
A. Avoid large number of back reflections that could interfere with normal test pattern.
B. Obtain a max response if the discontinuity is not originally oriented perpendicular to the ultrasonic beam.
C. Obtain the max number of entry surface reflections.
D. Obtain a discontinuity indication of the same height as the indication from the flat-bottom hole in a reference block.
B. Obtain a max response if the discontinuity is not originally oriented perpendicular to the ultrasonic beam.
An UT instrument display pattern containing a large number of low-level indications (grass/hash) could be caused by:
A. a crack
B. a large inclusion
C. coarse-grained material
D. a gas pocket
C. coarse-grained material
Which of the following materials of the same alloy is most likely to produce the greatest sound attenuation over a given distance?
A. A hand forging
B. A coarse-grained casting
C. An extrusion
D. The attenuation is equal in all materials
B. A coarse-grained casting
On many ultrasonic testing instruments, an operator can remove that portion of the display presentation that represents water distance by adjusting a:
A. pulse length control
B. reject control
C. sweep delay control
D. sweep length control
C. Sweep delay control
What is another way to express 100 000 cycles per second?
A. 0.1kHz
B. 10kHz
C. 100kHz
D. 100MHz
C. 100kHz
A term used to describe numerous small indications on the instrument display resulting from test part structure, numerous small discontinuities, or both is often referred to as:
A. multiple back reflections
B. multiple front reflections
C. grass or hash
D. resonance
C. grass or hash
If the major dimensions of a defect in a 6” aluminum plate lies parallel to the entry surface it will best be detected by:
A. a straight beam test
B. an angle beam test
C. a surface wave test
D. a lamb wave test
A. a straight beam test
The depth of a discontinuity cannot be determined when using
A. straight beam testing method
B. through transmission testing method
C. angle beam testing method
D. immersion testing method
B. through transmission testing method
When inspecting coarse-grained material, a sound wave is most easily scattered by the grain structure by a frequency of:
A. 1MHZ
B. 5MHZ
C. 15MHZ
D. 25MHZ
D. 25MHZ
When performing a surface wave test, indications may result from:
A. improper frequency
B. oil on the surface
C. a surface discontinuity
D. the acoustical velocity of aluminum
C. a surface discontinuity
A SEPARATE time baseline imposed on the viewing display of some ut instruments that permits measurements of distances is often referred to as:
A. an initial pulse
B. a time/distance line
C. an electronic gate
D. a sweep line
C. an electronic gate
A circuit that modifies the return signal from the receiving transducer into a form suitable for display on an oscilloscope or other output device is called a:
A. pulser
B. receiver-amplifier
C.clock
D.sweep
B. receiver-amplifier
A circuit that coordinates electronic operation of the entire ultrasonic instrument system is called:
A. damping
B. a receiver-amplifier
C. a clock
D. a power supply
C. a clock
In addition to other functions, a transducer manipulator in a mechanical immersion-scanning unit permits:
A. use of the through-transmission technique
B. use of high scanning speeds
C. detection of obliquely oriented discontinuities
D. utilization of less skilled operators
C. detection of obliquely oriented discontinuities
The component in a conventional immersion system that spans the width of the immersion tank is called:
A. an articulator
B. a bridge
C. a manipulator
D. a search tube
B. a bridge
The component in an ut immersion system that is used to adjust and maintain a known transducer angle is called:
A. a carriage
B. a manipulator
C. a search tube
D. an index system
B. a manipulator
An amplitude type gate is necessary for all:
A. shear wave examinations
B. long. wave examinations
C. automatic examinations
D. manual examinations
C. automatic examinations
When a C-scan recording is used to produce a permanent record of an UT test, the info displayed is typically the discontinuity’s
A. depth and size
B. depth, orientation and size
C. location and depth
D. location and size
D. location and size
Surface waves (Rayleigh) are more highly attenuated by a:
A. curved surface
B. heavy couplant
C. thin couplant
D. sharp corner
B. heavy couplant
For a given incident angle, as the FREQUENCY of the transducer increases, the refracted angle:
A. increases
B. decreases
C. stays the same
D. cannot be determined
C. stays the same
Refracted energy assumes a new direction of propagation when the ___ is changed
A. principal angle
B. reflected angle
C. critical angle
D. incident angle
D. incident angle
If a transducer is vibrating at a frequency and injecting ultrasonic energy through water into a steel specimen:
A. the sound wavelength is the same in both
B. the sound frequency in the water is less than the frequency in steel
C. the sound wavelength is not the same in both water and steel
D. the sound frequency in water is greater than the sound in steel
C. the sound wavelength is not the same in both water and steel
When a long sound wave strikes a water-steel interface at an angle of incidence of 15 degrees:
A. all the sound energy is reflected back into the water at an angle of 15
B. part of the sound energy is reflected at 15 and part is refracted into the steel at an angle of less than 15
C. part of the sound energy is reflected at 15 and part is refracted along the water-steel interface
D. part of the sound energy is reflected at 15 and part is refracted into the steel at an angle greater than 15
D. part of the sound energy is reflected at 15 and part is refracted into the steel at an angle greater than 15
A flat normal beam probe has a near zone of 25mm in water. If used in direct contact on steel the near zone would be
A) 3mm
B) 6mm
C) 8mm
D) 12mm
B) 6mm
1/4 /25
Attenuation of ultrasonic energy is an inherent property of all materials and is
A) a constant 0.5 dB/cm
B) variable with alloy and test frequency
C) a function of acoustic impedance
D) both b and c
B) variable with alloy and test frequency
A focused probe is positioned in water 5 cm over a plate 10cm thick. The probe having a focal length in water of 6 cm will focus
A) 1 cm above the plate
B) 0.25 cm from the entry surface of the plate
C) 0.25 cm from the back surface of the plate
D) 0.4 cm into the water on the opposite side of the plate
B) 0.25 cm from the entry surface of the plate
When performing a pulse-echo test, if you scanned over a large defect with the same acoustic impedance as the material you were testing
A) maximum response would occur only at right angles
B) the AVG (DGS) method would be used for sizing
C) it would not be detected
D) detection would depend on how much gain over reference you were scanning with
C) it would not be detected
Modern ultrasonics uses signal processing methods like signal averaging, spectral analysis, deconvolution auto-correlation and filtering to
A) increase scanning speeds of automated systems
B) eliminate ultrasonic operators
C) provide smoother looking A-scans
D) both locate and characterize flaws
D) both locate and characterize flaws
In ultrasonic spectrum analysis, the effect of increasing metal grain size on the spectra would be
A) reduction in lower frequencies
B) reduction in higher frequencies
C) an increase in frequencies at the corresponding grain size
D) none of the above
B) reduction in higher frequencies
When trying to obtain a “noise free” signal a filter is sometimes used. If this filter limits signals to just a narrow range of frequencies it is called a _________ filter.
A) low-pass
B) high-pass
C) band-pass
D) broad-pass
C) band-pass
In ultrasonic testing, one of the best means of conveying a large quantity of information about a test piece is by
A) B-scans
B) C-scans
C) ultrasonic imaging
D) the tandem probe technique
C) ultrasonic imaging
Acoustic imaging techniques permit the visualisation of objects because
A) sound can be converted to light when passing through metal
B) of the polarity of transverse waves
C) sonoluminescence occurs in couplant
D) acoustic waves obey the same equations as optical waves
D) acoustic waves obey the same equations as optical waves
Ultrasonic waves with frequencies of 400MHz to 2GHz would be used in
A) acoustic microscopy
B) concrete testing
C) ultrasonic cleaning
D) nothing, it is not possible to generate ultrasound in this range
A) acoustic microscopy
If the “focal spot” size of the beam from a focused transducer was increased by increasing the focal length
A) sensitivity would increase
B) resolution would decrease
C) all flaws would be detected
D) no indications would be rejectable
B) resolution would decrease
The advantage of a short duration excitation pulse applied to a normal transducer is
A) wideband frequency operation
B) high resolution
C) reduced attenuation loses
D) all of the above
D) all of the above
For a SINGLE crystal piezoelectric material used in an ultrasonic transducer THE ANGLE to the CRYSTAL AXIS that it is cut determines
A) frequency
B) direction of deformation
C) Q-factor
D) both a and b
B) direction of deformation
Alignment of the small domains in polycrystalline ferro-electric materials, such as PZT, is called
A) poling
B) polarisation
C) both a and b
D) domaining
C) both a and b
In a ferroelectric ceramic such as PZT, the curie temperature is the temperature above which
A) the piezoelectric domain structure is lost
B) water is driven out of the crystal
C) polarity reverses
D) electrodes cannot be deposited
A) the piezoelectric domain structure is lost
The parallel of mechanical resonance frequency of a piezoelectric element occurs when the element thickness is
A) one quarter wavelength
B) one half wavelength
C) one wavelength
D) none of the above
B) one half wavelength
Backing materials used in ultrasonic transducers are used for
A) changing frequency bandwidths
B) focusing the beam
C) de-focusing the beam
D) none of the above
A) changing frequency bandwidths
The purpose of putting one or more matching layers between the front face of a probe and the coupling medium is
A) to decrease ringing time
B) to improve coupling
C) to provide a delay line effect
D) not known by probe manufacturers
B) to improve coupling
Variations in a probes’ actual frequency and its nominal frequency by as much as 5%
A) put the probe “out of spec”
B) have significant effects on test results
C) are acceptable in NDT
D) none of the above
C) are acceptable in NDT
Electromagnetic acoustic transducers (EMATs) are made from
A) silicon chips
B) ferro-magnetic crystals
C) ferro-electric crystals
D) coils of wire
D) coils of wire
The most common single measurement made on ultrasonic transducers is determination of
A) nature of sound field
B) bandwidth
C) actual centre frequency
D) none of the above
A) nature of sound field
Velocity of ultrasonic waves in steel at 10°C. as compared to 40°C. are
A) slower
B) faster
C) the same
D) dependant on the alloy of steel maybe faster or slower
B) faster
The measured pulse length determines a probes’
A) frequency
B) acoustic impedance
C) damping
D) depth resolution
D) depth resolution
Probes used in ultrasonic contact testing are checked periodically for performance when in regular use. Which characteristic would not be checked daily?
A) probe index
B) beam angle
C) beam profile
D) overall system gain
C) beam profile
A deviation in actual refracted angle of + or - 2 degrees will result in
A) errors in depth calculations
B) errors in stand-off calculations
C) errors in sound path calculations
D) both a and b
D) both a and b
When using perspex wedges for contact testing, if the actual refracted angle varies by more than + or - 2 degrees the wedge should be
A) replaced
B) re-ground
C) re-calibrated
D) either a or b may be required
D) either a or b may be required
The control on an ultrasonic machine which enables electrical signals to be decreased by known values, usually dB, is called a(n)
A) attenuator
B) matching box
C) reject control
D) damping control
A) attenuator
The line of maximum sound intensity in the far zone of an ultrasonic beam, and its projection back to the near zone is called the
A) half angle of divergence
B) beam spread
C) beam profile
D) beam axis
D) beam axis
A presentation where-by the relative amplitude of ideal reflectors of different sizes are plotted against different distances is called
A) DGS diagrams
B) AVG diagrams
C) DAC curves
D) both a and b
D) both a and b
The dominant frequency of an ultrasonic flaw detection system depends on the
A) probe
B) machine receiver and amplifier
C) pulse propagation path
D) all of the above
D) all of the above
The amount by which the electrical signal from the ultrasonic transducer is amplified is
A) the gain
B) signal-to-noise ratio
C) 6
D) none of the above
A) the gain
In an A-scan presentation, the indication of the instant at which the pulse is applied to the transmitting crystal is the ________ indication.
A) initial pulse
B) threshold
C) R-F
D) sweep
A) initial pulse
Spreading the timebase interval to enable signals from a selected range to be displayed is called
A) magnification
B) delay
C) scale expansion
D) decompression
C) scale expansion
The distance between successive points of impingement of the beam axis on the entry surface after reflecting from the opposite side is called
A) stand-off
B) skip distance
C) sound path
D) none of the above
B) skip distance
The imaginary line that connects all the points of the same phase in a wave propagating in a medium is referred to as the
A) phase line
B) wave front
C) interphase index
D) refractive index
B) wave front
Which of the following methods would not use pulsed ultrasound?
A) pulse-echo
B) pitch-catch
C) through-transmissions
D) all of the above would use pulse ultrasound
D) all of the above would use pulse ultrasound
When using the “pitch-catch” method of ultrasonic testing, which is not true?
A) two piezoelectric elements are commonly used
B) all the piezoelements are always mounted in one housing
C) both shear and longitudinal modes can be used
D) one element is dedicated to transmission
B) all the piezoelements are always mounted in one housing
Sizing of defects located in the near zone is difficult because of
A) uncertainties of sound pressure along the beam axis
B) uncertainties of sound pressure at right angles to the beam axis
C) frequency variation
D) both a and b
D) both a and b
Maximum acoustic energy is coupled from one medium to another when the acoustic impedance of the first medium is _________ the second.
A) less than
B) greater than
C) the same as
D) twice the value of
C) the same as
Which of the following terms is not used to describe methods of coupling ultrasonic energy into a test specimen?
A) non-invasive
B) direct contact
C) immersion
D) gap
A) non-invasive
In immersion testing, the hindrance of multiple interface signals that results from the pulse bouncing between the test piece and probe on normal incidence is avoided by
A) decreasing receiver gain
B) increasing the distance between probe and work surface
C) increasing damping
D) use of the interface-lock feature
B) increasing the distance between probe and work surface
Which mode of wave used in nondestructive testing is NOT initially produced by mode conversion?
A) longitudinal
B) shear
C) transverse
D) Rayleligh
A) longitudinal
Resonance methods of thickness testing are no longer commonly used. This technique used
A) continuous wave oscillators
B) pulsed wave packets
C) surface waves
D) none of the above
A) continuous wave oscillators
To avoid distortion of received ultrasonic signals the receiver amplifier should have similar bandwidth characteristics as the
A) test piece resonant frequency
B) receiving transducer
C) transmitting transducer
D) none of the above, receiver bandwidth is not important
B) receiving transducer
Transducers with high-Q factor have
A) broadband-type pulses
B) poor penetrating ability
C) poor resolution compared to low-Q factor
D) all of the above
C) poor resolution compared to low-Q factor
In hardcopy presentations of C-scans, the item recorded is
A) a absence of signal
B) the presence of a signal
C) the depth of a signal
D) a or b
D) a or b
Significant advantage of ultrasonics over radiography is
A) it is safe
B) it can be used on ferrous and non-ferrous metals
C) all defects in any piece can be located
D) the ability to use it underwater
A) it is safe
Which is not a characteristic of ultrasound used to evaluate materials
A) attenuation
B) density
C) magnitude of echoes
D) velocity
B) density
Which is not a welding defect term
A) porosity
B) slag
C) lamination
D) hot cracking
C) lamination
The orientation of the defect with respect to the direction of the ultrasonic beam determines
A) whether the reflected pulse returns to the receiver
B) if immersion or contact testing is used
C) if immersion or gap testing is used
D) none of the above
A) whether the reflected pulse returns to the receiver
To inspect tubular products using the ultrasonic method,
A) longitudinal wave mode is used
B) shear wave mode is used
C) surface wave mode is used
D) all wave modes can be used
D) all wave modes can be used
Tubing i.e. tubular products, is best inspected by ultrasonics using the __________ method.
A) pulse-echo
B) transmit-receive
C) induction coil
D) time of flight diffraction
A) pulse-echo
Thickness measurements of plates are made using ______ waves.
A) Rayleigh
B) shear
C) compressional
D) Lamb
C) compressional
Ultrasonic testing of concrete would be carried out using frequencies in the range of
A) 100 to 500 Hz
B) 25 to 100 kHz
C) 0.5 to 1 MHz
D) 2 to 4 MHz
B) 25 to 100 kHz
Ultrasonic pulse-echo techniques are used on livestock to
A) establish fat profiles
B) modify behaviour
C) increase reproductive capability
D) all of the above
A) establish fat profiles
The probe movement that MAINTAINS A CONSTANT DISTANCE from an indication while varying the direction of the beam is called
A) orbiting
B) pivoting
C) traversing
D) lateral movement
A) orbiting
The purpose of water jets in ultrasonic inspection of hot plate (100°C.) is
A) to provide a coupling medium
B) to keep the probe cool
C) both a and b
D) none of the above
C) both a and b
