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