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NDT Level 2
UT Level I-II General exam study guide
151
Engineering
Undergraduate 2
02/21/2013
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Term
The Divergence of an ultrasonic beam is dependant on:
 Definition
Transducer wavelength and diameter
Term
When a longitudinal wave is incident upon an inclined interface between zero degrees
and the first critical angle:
 Definition
Shear waves and longitudinal waves are produced in the second material
Term
The piezoelectric material in a search unit which vibrates to produce ultrasonic waves
is called:
 Definition
A transducer element or crystal
Term
When a longitudinal wave is incident upon an inclined interface and is refracted at
ninety degrees, the angle of the incident longitudinal wave is called:
 Definition
The first critical angle
Term
When a longitudinal wave sound beam passes through an acoustic interface at some
angle other than zero degrees:
 Definition
Reflection, refraction and mode conversion will occur
Term
Which of the following can be a source of spurious ultrasonic signals?
(a) Surface roughness of the test piece
(b) Mode conversion within the test piece
(c) Shape or contour of the test piece
 Definition
All of the above..(a) Surface roughness of the test piece
(b) Mode conversion within the test piece
(c) Shape or contour of the test piece
Term
A noisy base line, or hash may result in:
 Definition
Large grain size
Term
Sound waves which travel on the surface of a solid in a manner similar to waves on a
water surface are called:
 Definition
Rayleigh waves
Term
Lamb waves are formed in a part which has:
 Definition
A thickness approximately equal to the wavelength
Term
Which type(s) of sound wave modes will propagate through liquids?
 Definition
Longitudinal Waves
Term
When the motion of the particles of a medium is transverse to the direction of
propagation, the wave being transmitted is called a:
 Definition
Shear waves
Term
Which of the following test frequencies would generally provide the best penetration
in a 12 inch thick specimen of coarse-grained steel?
1.0 MHz, 2.25 MHz, 5.0 MHz, 10 MHz
 Definition
1.0 MHz
Term
An oscilloscope display in which the screen base line is adjusted to represent the one
way distance in a test piece is called a:
 Definition
B Scan Display
Term
A common use of ultrasonic testing is:
 Definition
Detecting sub-surface indications
Term
Sound waves of a frequency beyond the hearing range of the human ear are referred
to as ultrasonic waves or vibrations, and the term embraces all vibrational waves of
frequency greater than approximately:
 Definition
20 KMz
Term
Y cut crystals produce:
 Definition
Shear waves
Term
The cable that connects the ultrasonic instrument to the search unit is specially
designed so that one conductor is centred inside another. The technical name for such
a cable is:
 Definition
Coaxial cable
Term
As ultrasonic frequency increases:
 Definition
wavelength decreases
Term
In an A scan presentation, the amplitude of vertical indications on the screen
represents the:
 Definition
Amount of ultrasonic sound energy returning to the search unit
Term
Loss of the test piece back wall echo during scanning may be caused by:
 Definition
A discontinuity which is not parallel to the entry surface
Term
When a sound beam is reflected:
 Definition
The angle of reflection equals the angle of incidence
Term
Which of the following circuits converts electrical energy to ultrasonic energy?
 Definition
The transducer
Term
An instrument display in which the horizontal base line represents elapsed time and
the vertical deflection represents signal amplitudes is called:
 Definition
A scan
Term
Which of the following circuits provides short duration, high energy pulses which are
used to excite the transducer?
 Definition
The Pulse Generator
Term
A cross section view of a test piece is produced by which of the following?
 Definition
B-Scan
Term
Echo amplitude losses may be caused by:
(a) Entry surface roughness
(b) Coarse grain size
(c) Discontinuity orientation
(d) All of the above
 Definition
all of the above
Term
Which of the following is an advantage of using a focused transducer?
 Definition
Greater sensitivity is achieved in the transducer's useable range
Term
Which of the following circuits provide current to operate the ultrasonic instrument?
 Definition
The power supply
Term
Which of the following is a true statement?
(a) Higher frequencies produce lower sensitivity
(b) Higher frequencies produce longer wavelengths
(c) Thicker crystals produce lower frequency transducers
(d) Longer wavelengths produce higher sensitivity
 Definition
(c) Thicker crystals produce lower frequency transducers
Term
Which type(s) of sound wave modes will propagate through solids?
 Definition
Longitudinal, Shear & Surface waves
Term
The longitudinal wave incident angle at which the refracted shear wave angle equals
ninety degrees is called:
 Definition
The Second critical angle
Term
The amount of beam divergence from a crystal is primarily dependent on
the:
 Definition
Frequency and crystal size
Term
In ultrasonic testing, a liquid coupling medium between the crystal surface and the
part surface is necessary because :
 Definition
An air interface between the crystal surface and the part surface would almost
completely reflect the ultrasonic vibrations
Term
X cut crystals produce:
 Definition
Longitudinal waves
Term
Lower frequency transducers are normally used:
 Definition
Where deeper penetration is required
Term
All other factors being equal, which of the following modes of vibration has the
greatest velocity?
 Definition
Longitudinal wave
Term
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:
 Definition
Angulation
Term
The angle of a refracted shear wave generated as a sound wave passes at an angle
through an acoustic interface is dependant on:
 Definition
The acoustic impedances of the materials of each side of the interface
Term
Which of the following is a likely effect of a rough test piece surface?
(a) An improved ultrasonic signal to noise ratio
(b) A more penetrating sound beam
(c) Loss of discontinuity signal amplitude
(d) Higher test reliability
 Definition
(c) Loss of discontinuity signal amplitude
Term
Wavelength is:
 Definition
The distance from trough to trough or from peak to peak of a sound wave
Term
The velocity of surface waves is approximately _______________ the velocity of
shear waves in the same material.
 Definition
Nine-tenths
Term
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:
 Definition
The sweep delay
Term
A disadvantage of using natural quartz crystals in a search unit is that:
 Definition
It is the least effective generator of ultrasonic energy of all commonly used
materials
Term
The formula Sin A/Sin B = VA/VB is known as:
 Definition
Snell's Law
Term
A 25 MHz search unit would most likely be used during:
 Definition
Immersion testing
Term
A technique in which two transducers are used, one on each side of the test piece, is
called:
 Definition
Through transmission testing
Term
Sound beam intensity is irregular in the area called:
 Definition
The near field
Term
A more highly damped transducer crystal results in:
 Definition
Better resolution
Term
The process of comparing an instrument or device with a standard is called:
 Definition
Calibration
Term
Scattering of an ultrasonic beam is most pronounced when:
 Definition
Material grain size and wavelength are comparable
Term
Ultrasonic testing is:
 Definition
Sound which has a frequency or pitch above the range of the human ear
Term
Which technique would most likely be used to examine a weld, with the weld cap still
in place?
 Definition
Angle beam testing
Term
The maximum frequency usually used for contact testing is:
 Definition
5 MHz
Term
Higher frequency transducers are normally used:
 Definition
In immersion testing applications
Term
Typical ultrasonic testing frequencies are:
 Definition
1 MHz to 5 MHz
Term
‘25 million cycles per second’ can also be stated as:
 Definition
25 MHz
Term
A disadvantage of using a high frequency ultrasonic transducer is:
 Definition
It is scattered more by coarse grained material
Term
Which of the following circuits provides timing signals to the pulser?
 Definition
The clock
Term
Which of the following search units would contain the thinnest quartz crystal?
 Definition
A 25 MHz search unit
Term
With longitudinal wave incident at angles between the first and second critical angles:
 Definition
Only shear waves are produced in the second material
Term
Sound velocity is described by which of the following relationships?
 Definition
Wavelength times frequency
Term
The relationship between the longitudinal wave incident angle and the refracted shear
wave angle is defined by:
 Definition
Snell's law
Term
Acoustic impedance is defined by which of the following relations?
 Definition
Material density × velocity
Term
The upper limit of human hearing is normally considered to be about:
 Definition
20 kHz
Term
Reference standards containing a series of flat bottom holes of the same diameter at
different depths in each block are called?
 Definition
Distance-amplitude blocks
Term
During ultrasonic testing by the immersion method, it is frequently necessary to
angulate the search unit when a discontinuity is located at an angle in order to:
 Definition
Obtain a maximum response if the discontinuity is not originally oriented
perpendicular to the ultrasonic beam
Term
Which of the following transducer materials is the most efficient receiver of
ultrasonic energy?
 Definition
Lithium sulphate
Term
An ultrasonic wave in which particle displacement is 90 degrees to the direction of
wave propagation is called a:
 Definition
Shear wave
Term
An advantage of using lithium sulphate in search units it that:
 Definition
It is one of the most efficient receivers of ultrasonic energy
Term
Moving a search unit over a test surface either manually or automatically is referred
to as:
 Definition
Scanning
Term
Most commercial ultrasonic testing is performed at frequencies between:
 Definition
1 MHz and 25 MHz
Term
For a transducer with any given Q, resolution increases with:
 Definition
Frequency
Term
Resolving power of a transducer is directly proportional to its:
 Definition
bandwidth
Term
The term is used to refer to the product of wave velocity and density is:
 Definition
Acoustic Impedance
Term
For an ultrasonic beam with normal incidence, the reflection coefficient is given by:
 Definition
[(Z1-Z2)2]/[Z1+Z2)2]
Term
For an ultrasonic beam with normal incidence the transmission coefficient is given
by:
 Definition
[(4) (Z1)(Z2)]/[(Z1+Z2)2]
Term
Snell's law is given by which of the following:
 Definition
(Sin A)/(Sin B) = VA/VB
Term
Snell's law is used to calculate:
 Definition
Angle of refraction
Term
Calculate the refracted shear wave angle in steel [VS = 0.323cm/microsec] for an
incident longitudinal wave of 37.9 degrees in Plexiglas [VL = 0.267cm/microsec]
 Definition
45 degrees
Term
Calculate the refracted shear wave angle in steel [VS = 0.323cm/microsec] for an
incident longitudinal wave of 45.7 degrees in Plexiglas [VL = 0.267cm/microsec]
 Definition
60 degrees
Term
Calculate the refracted shear wave angle in aluminium [VS = 0.31cm/microsec] for an
incident longitudinal wave of 43.5 degrees in Plexiglas [VL = 0.267cm/microsec]
 Definition
53 degrees
Term
Calculate the refracted shear wave angle in aluminium [VS = 0.31cm/microsec] for an
incident longitudinal wave of 53 degrees in Plexiglas [VL = 0.267cm/microsec]
 Definition
68 degrees
Term
Lithium sulphate, barium titanate and lead metaniobate are examples of:
 Definition
Piezoelectric elements
Term
The particle motion for compression waves is:
 Definition
Parallel to wave propagation
Term
Shear waves for ultrasonic testing are usually produced:
 Definition
Y cut crystals
Term
Near surface resolution can be improved by:
 Definition
Using a focused transducer
Term
The most important requirement for paintbrush transducer is:
 Definition
Uniform beam intensity across the transducer
Term
Which of the following is an advantage of a focused transducer?
 Definition
Higher resolution over a limited range
Term
Which of the following is intended to be a ‘first cut’ or rough inspection device to be
followed by more precise evaluation of any discontinuities found?
 Definition
Paintbrush transducer
Term
A wider entry surface indication or pulse may result from:
 Definition
Side lobes of the sound beam being reflected from a rough surface
Term
Which of the following methods might be used to reduce attenuation losses in an
ultrasonic test?
 Definition
Use a lower frequency transducer
Term
When comparing discontinuity echoes to equivalent flat bottom hole echoes in
materials with similar impedance, surface finish and attenuation:
 Definition
(a) The flaw is never larger than the flat bottom hole
(b) The flaw is never smaller than the flat bottom hole
(c) The flaw is always smaller than the flat bottom hole
(d) None of the above
Term
An advantage of immersion testing is that:
 Definition
High test frequencies may be used and that Irregularly shaped test pieces can be virtually completely examined
Term
An ultrasonic data display which shows a plan view presentation of the data is called:
 Definition
C scan
Term
An ultrasonic display which shows a cross section of the test piece and any flaws
which are found are called:
 Definition
B scan
Term
An ultrasonic display which shows echo locations and amplitude is called:
 Definition
A scan
Term
An advantage of using lower frequencies during ultrasonic testing is that:
 Definition
Sensitivity to unfavourable oriented flaws is improved
Term
A method of compensating for the ‘dead zone’ or near surface resolution problems is
to:
 Definition
Re-inspect from the opposite side of the test piece if geometry permits
Term
When testing a test piece with parallel front and back surfaces, no back wall echo can
be obtained. Which of the following actions might enable you to obtain a back wall
echo?
 Definition
Use a lower frequency transducer
Term
Materials which can readily be inspected with frequencies of 1 to 5 MHz are:
 Definition
Magnesium, titanium and steel
Term
When variations are noticed in the front surface reflection, the test piece should be
inspected for possible near surface discontinuities by:
 Definition
Inspecting from the opposite side
Term
Forging bursts are most often orientated:
 Definition
In a random manner
Term
The purpose of adding a wetting agent to an immersion bath is:
 Definition
To eliminate air bubbles in the bath
Term
During immersion testing of pipe or tubing the incident longitudinal wave angle must
be limited to a narrow range. The reason for the upper limit is:
 Definition
To avoid complete reflection of ultrasound from the test piece
Term
A calibration for immersion ultrasonic testing of pipe or tubing should establish a
transducer position such as:
 Definition
All ultrasound enters the test piece
Term
One way of identifying spurious echoes in an ultrasonic test is:
 Definition
(a) Re-test the test piece to verify that the echoes are repeatable
(b) Clean and re-test the teat piece to determine if the echoes can be eliminated
(c) Use the reject control to eliminate unwanted echoes
(d) Decrease the gain to see if the echoes can be eliminated
Term
During immersion ultrasonic testing of pipe or tubing, spurious echoes may be caused
by:
 Definition
Dirt on the test piece, Grease on the test piece, Air bubbles on the test piece
Term
Typical frequencies which might be used to perform ultrasonic testing of concrete
are:
 Definition
25 to 100 kHz
Term
Typical frequencies which might be used to perform ultrasonic testing of ferrous and
non-ferrous welds are:
 Definition
1 MHz to 5 MHz
Term
Which of the following materials would probably require testing at the lowest
frequency?
(a) Small grained mild steel
(b) Mild steel castings
(c) Mild steel forgings
(d) Cast iron
 Definition
(d) Cast iron
Term
Which of the following is an advantage of contact testing over immersion?
(a) Ability to maintain uniform coupling on rough surface
(b) Longer dead time near the front surface of the test piece
(c) Ease of field use
(d) Ability to continuously vary incident wave angle during test
 Definition
(c) Ease of field use
Term
Which of the following is a disadvantage of contact testing?
(a) Ability to maintain uniform coupling on rough surface
(b) Ease of field use
(c) Greater penetrating power than immersion testing
(d) Less penetrating power than immersion testing
 Definition
(a) Ability to maintain uniform coupling on rough surface
Term
A typical application for a through transmission technique is:
 Definition
Bond/unbond testing
Term
An ultrasonic technique in which two transducers are used, in a constant position
relative to each other, is:
 Definition
Through transmission
Term
Which of the following cast materials could most likely be successfully ultrasonically
tested?
 Definition
Low carbon steel
Term
Which of the following product forms would probably be tested at the lowest
frequency? (a) Forgings
(b) Hot rolled plate
(c) Castings
(d) Extrusions
 Definition
(c) Castings
Term
Addition of approximately 6% antimony as an alloying element could be expected to
increase the ultrasonic inspectability of which of the following materials?
 Definition
Pure lead
Term
Strong signals which travel across the horizontal time base of an A scan presentation
while the transducer is motionless on the test piece are probably:
 Definition
Electrical interference
Term
Excessive ringing of the transducer could be caused by:
 Definition
Loose crystal
Term
When inspecting a long bar with a longitudinal wave from one end, a series of
additional echoes are seen immediately after the bottom surface reflection. these are
most likely:(a) Refracted shear and longitudinal waves caused by beam spread
(b) Flaw indications
(c) Multiples of the back surface reflection
(d) None of the above
 Definition
(d) None of the above
Term
One of the most apparent characteristics of a discontinuity echo, as opposed to a nonrelevant
indication is:
 Definition
Sharp, distinct signal
Term
Typical immersion test frequencies for wrought aluminium are:
 Definition
10 MHz and up
Term
Choice of ultrasonic test frequency depends upon which of the following? (a) Surface condition
(b) Minimum size discontinuity to be detected
(c) Level of grain noise
(d) All of the above
 Definition
(d) All of the above
Term
Polished, flat surfaces are undesirable for ultrasonic testing consideration because:
 Definition
The probe sticks to the surface because of suction
Term
The most effective liquid ultrasonic couplant (highest acoustic impedance) is:
 Definition
Glycerine
Term
When using a straight beam technique to examine a thick test piece what change(s)
would you expect to see in back wall echo size as you approach the side of the test
piece? (Transducer remains completely on test piece)
 Definition
Decrease
Term
What useful purpose may be served by maintaining grass on the baseline?
 Definition
To verify adequate coupling to the test piece
Term
Which of the following describes the sound field propagating in a piece of steel bar
stock which is being tested from one end with longitudinal waves?
 Definition
Decreasing according to the inverse square law
Term
When a probe is coupled to a solid, strong surface waves may be produced: (a) If a high frequency probe is used
(b) If the probe has only incomplete contact with the surface
(c) If the probe is large in diameter
(d) None of the above
 Definition
(d) None of the above
Term
To avoid interfering surface waves, low frequencies should only be used on:
 Definition
Castings
Term
Which of the following conditions would be most likely to cause strong, interfering
surface waves?
 Definition
Testing on a curved surface with a contoured wedge and transducer
Term
Flaw sizing by the 6 dB drop technique is applicable to:
 Definition
Large flaws relative to the sound beam
Term
How many decibels of attenuation correspond to an ultrasonic signal loss of from
100% to 25% on full screen height?
 Definition
12
Term
An increase in gain of how many decibels corresponds to a 5:1 increase in flaw echo
amplitude?
 Definition
14
Term
A focused sound beam is produced by a:
 Definition
Concave transducer
Term
A divergent sound beam is produced by:
 Definition
Convex lens
Term
A type of cast iron which has ultrasonic properties similar to steel is:
 Definition
White
Term
What effect does hardening have on acoustic velocity in steel?
 Definition
No effect
Term
Variation in acoustic velocity from one type of steel to another is usually less than:
 Definition
1%
Term
In general, which of the following materials would have the least ultrasonic
attenuation?
 Definition
Aluminium
Term
The velocity of lamb waves depends on:
 Definition
(a) Elastic constants of test material
(b) Plate thickness
(c) Frequency
Term
Which of the following is the most durable piezoelectric material?
 Definition
Quartz
Term
Which of the following methods are used to produce ultrasonic waves?
(a) Magnetostrictive methods
(b) Magnetoinductive methods
(c) Piezoelectric elements
(d) All of the above
 Definition
(d) All of the above
Term
Spurious indications may be caused by which of the following?
(a) Test piece edges
(b) Mode conversions
(c) Multiple reflections from a single interface
(d) All of the above
 Definition
(d) All of the above
Term
A reason for using a dual element search unit is:
 Definition
Improving near surface resolution
Term
A wheel transducer is normally considered:
 Definition
An immersion method
Term
Which of the following is not an advantage of a focused transducer?
 Definition
Deep penetration
Term
What type of search unit allows the greatest resolving power with standard ultrasonic
testing equipment?
 Definition
Focused
Term
The 50 mm diameter hole in an IIW block is used to:
 Definition
Check beam angle
Term
The 100 mm radius in an IIW block is used to:
 Definition
Calibrate angle beam distance
Term
Which of the following is a disadvantage of immersion test units?
 Definition
Portability
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