WorksheetsULTRASONIC
Total questions: 80
Worksheet time: 40mins
1. Of the following sound wave mode, which one has multiple or varying wave velocities?
Longitudinal waves
Shear waves
Transverse waves
Lamb waves
2. The only significant sound wave mode that will travel through liquid is:
shear
longitudinal
surface
Rayleigh
3. The acoustic impedance of a material is used to:
determine the angle of refraction at an interface
determine the attenuation within the material
determine the relative amounts of sound energy coupled through and reflected at an interface
determine the beam spread within the material
4. When angle beam contact testing a test piece , increasing the incident angle until the second critical angle is reached results in:
total reflection of a surface wave
45 degree refraction of the shear wave
production of a surface wave
none of the above
5. The simple experiment where a stick in a glass of water appears disjoined at the water surface illustrates the phenomenon of:
reflection
magnification
refraction
diffraction
The crystal thickness and transducer frequencies are related. The thinner the crystal:
The lower the frequency
The higher the frequency
there is no appreciable effect
none of the above
The length of the zone adjustment to transducer in which fluctuations in sound pressure occur is mostly affected by:
the frequency of the transducer
the diameter of the transducer
the length of transducer cable
both A and B
The differences in signals received from identical reflectors at different material distances from a transducer may be caused by:
material attenuation
beam divergence
near field effects
all of the above
Its is possible for a discontinuity smaller than the transducer to produce indications of fluctuating amplitude as the search unit is moved laterally if testing is being performed in the:
Fraunhofer zone
Near field
Snell field
Shadow zone
In immersion testing, the near field effects of a transducer may br eliminated by:
increasing transducer frequency
use of a larger diameter transducer
using an appropriate water path
use of a focused transducer
In the far field of uniform ultrasonic beam, sound intensity is ______ the beam centerline
minimum at
maximum at
maximum throughout twice the angle (sine = C/Df) where C is acoustic velocity, D is crystal diameter, and f is frequency
not related to orientation
Where does beam divergence occurs?
Near field
Far field
At the crystal
None of the above
As frequency increases in ultrasonic testing, the angle of beam divergence of a given diameter crystal:
decreases
remains unchanged
increases
varies uniformly through each wavelength
When examining materials for planar flaws oriented parallel to the part surface, what testing method is most often used?
Angle beam
Through-Transmission
Straight beam
Dual crystal
Rayleigh waves are influenced most by defects located:
one wavelength below the surface
six wavelengths below the surface
close to or on the surface
three wavelengths below the surface
Lamb waves can be used to detect?
Laminar-type defects near the surface of a thin material
lack of fusion in the center of a thick weldment
internal voids in different bonds
thickness changes in heavy plate material
Which of the following scanning methods could be classified as an immersion type test?
Tank in which the search unit and test piece are immersed
Squirter bubbler method in which the sound is transmitted in a column of flowing water
Scanning with wheel-type search unit with the transducer inside a liquid filled tire
All of the above
In an immersion test of a piece of steel or aluminium m, the distance appears on the display as a fairly wide space between the initial pulse and the front surface reflection because of:
reduced velocity of sound in water as compared to test specimen
increased velocity of sound in water as compared to test specimen
Temperature of the water
all of the above
What law can be used to calculate the angle of refraction within a metal for both longitudinal and shear waves?
Poissin’s Ratio Law
Snell’s Law
Fresnel’s Field Law
Charles’s Law
At an interface between two different materials, an impedance difference results in:
reflection of the entire incident energy at the interface
absorption of sound
division of sound energy into transmitted and reflected modes
none of the above
Ultrasonic wheel units may be used for which of the following types of examination ?
Straight or longitudinal examination
Angle-beam or shear wave examination
Surface wave or Rayleigh wave
All of the above
In the immersion technique, the distance between the face of the transducer and the test surface(water path) is usually adjusted so that the time required to send the sound beam through the water:
is equal to the time required for the sound to travel through the test piece
is greater than the time required for the sound to travel through the test pieces
is less than the time required for the sound to travel through the test piece
none of the above
In a B-scan display, the length of a screen indication from a discontinuity is related to:
a discontinuity’s thickness as measured parallel to the ultrasonic beam
the discontinuity’s length in the direction of the transducer travel
both A and B
none of the above
On an A-scan display, the “dead zone” refers to:
the distance contained within the near field
the area outside the beam slread
the distance covered by the front surface pulse width and recovery time
the area between the near field and far field
Of the following scan types, which one can be used to produce a recording of flaw area superimposed over a plan view of the test piece?
A-scan
B-scan
C-scan
D-scan
In straight(normal) beam contact testing, a reduction in the back surface reflection amplitude could indicate m:
Inadequate coupling
a flaw which is not normal to the beam
all of the above
a near surface defect that cannot be resolved from the main bang (initial pulse)
A special scanning device with the transducer mounted in a tire-like container filled with couplant is commonly called:
a rotating scanner
an axial scanner
a wheel transducer
a circular scanner
Which best describes a typical display of a crack whose major surface is perpendicular to the ultrasonic beam?
A broad indication
A sharp indication
The indication will not show due to improper orientation
A broad indication with high amplitude
A primary purpose of a reference standard is:
to provide a guide for adjusting instrument controls to reveal discontinuities that a considered harmful to the end of the product
to give the technician a tool for determining exact discontinuity size
to provide assurance that all discontinuities is smaller than a certain specified reference reflector are capable of being detected by the test
to provide a standard reflector which exactly simulates actual discontinuities of a critical size
Compensation for the variation in echo height related to variations in discontinuity depth in the test material is known as:
transfer
attenuation
distance amplitude correction
interpretation
During a straight beam ultrasonic test a discontinuity indication is detected which is small in amplitude compared to the loss in amplitude of back reflection. The orientation of this discontinuity is probably:
parallel to the test surface
parallel ñ 5ø from the test surface
parallel to the sound beam
such that complete loss of back reflection will result
Gas discontinuities are reduced to flat discs or other shapes parallel to the surface by:
rolling
machining
casting
welding
In which zone does the amplitude of an indication from a given discontinuity diminish exponentially as the distance increaes
Far field zone
Near field zone
Dead zone
Fresnel zone
A set of standard reference blocks with the same geometrical configuration and dimensions other than the size if the calibration reflectors, eg. flat bottom holes is called a set of:
distance/amplitude standards
area/amplitude standards
variable frequency blocks
beam spread measuring blocks
The angle at which 90ø refraction of longitudinal soundwave is reached is called:
the angle of incidence
the first critical angle
the angle of maximum reflection
the second critical angle
Attenuation is a difficult quantity to measure accurately, particularly in solid materials, at the test frequencies normally used. The overall result usually observed includes other loss mechanisms that can include:
beam spread
couplant mismatch
test piece geometry
all of the above
Large grains in a metallic test specimen usually result in:
decrease or loss of back surface reflection
large “hash” or noise indications
decrease in penetration
all of the above
Delay-tip (stand-off) type contact search units are primarily used for:
defect detection
sound wave characterization
thickness measurement or flaw detection in thin materials
attenuation measurements
Compute the wavelength of ultrasonic energy in lead at 1 MHz, VL =2.1 x 105 cm/sec, V = wavelength x frequency
0.21 cm
21 cm
0.48 cm
4.8 x 10-5 cm
For aluminium and steel the longitudinal velocity is approximately _____ the shear velocity.
equal to
twice
one-half of
four times
In inspecting a 4-inch diameter threaded steel cylinder for radical cracks extending from the root of the threads, it would be preferable to transmit:
shear waves at an angle to the threads
longitudinal waves from the end of the cylinder and perpendicular to the direction of the thread roots
surface waves perpendicular to the thread roots
shear waves around the circumference of the cylinder
The angle former by an ultrasonic wave as it enters a medium of different velocity than the one from which it came and a line drawn perpendicular to the interface between the two media is called:
the angle of incidence
the angle of refraction
the angle of rarefaction
the angle of reflection
The process of adjusting an instrument or device to a reference standard is referred to as:
angulation
scanning
correcting for distance-amplitude variations
calibration
The angular position of the reflecting surface of a planar discontinuity with respect to the entry surface is referred to as:
the angle of incidence
the angle of refraction
the orientation of the discontinuity
none of the above
In ultrasonic testing, the time duration of the transmitted pulse is referred to as:
the pulse length or pulse width
the pulse amplitude
the pulse shape
none of the above
Which of the following modes of vibration exhibits the shortest wavelength at a given frequency and in a given material?
Longitudinal wave
Compression wave
Shear wave
Surface wave
In general, shear waves are more sensitive to small discontinuities than longitudinal waves for a given frequency and in a given material because:
the wavelength of shear waves is shorter than the wavelength of longitudinal waves
shear waves are not as easily dispersed in the material
the direction of particle vibration for shear waves is more sensitive to discontinuities
the wavelength of shear waves is longer than the wavelength of longitudinal waves
In general, which of the following modes of vibration would have the greatest penetrating power in a coarse-grained material if the frequency of the waves are the same?
Longitudinal
Shear
Transverse
All of the above modes would have the same penetrating power
The distance from a given point on an ultrasonic wave to the next corresponding point is referred to as:
frequency
wavelength
velocity
pulse length
The speed at which ultrasonic waves travel through a material is known as its:
velocity of sound energy
pulse repetition rate of sound energy
pulse recovery rate of sound energy
ultrasonic response of sound energy
A substance that reduces the surface tension of a liquid is referred to as:
a couplant
an ultrasonic dampener
a wetting agent
none of the above
The transducers most common found in ultrasonic search units (probes) used for discontinuity testing utilise:
magnetostriction principles
piezoelectric principles
mode conversion principles
none of the above
The firmula sine1/V1 = sine2/V2 is referred to as:
the acoustical impedance ratio formula
the phase conversion formula
the Fresnel zone formula
Snell’s law
The amount of energy reflected from a discontinuity will be dependent on:
the size of the discontinuity
the orientation of the discontinuity
the type of discontinuity
all of the above
If an ultrasonic wave is transmitted through an interface of two materials in which the first material has a higher acoustic impedance value but the same velocity value as the second material, the angle of refraction will:
be greater than the angle of incidence
be less than the angle of incidence
be same as the angle of incidence
be beyond the critical angle
The amplifier range over which the unsaturated signal response increases in amplitude in proportion to the discontinuity surface area is the:
sensitivity range
linear range
selectivity range
resolution range
One of the most common applications of ultrasonic tests employing shear waves is:
detection of discontinuities in welds, tube and pipe
determination of elastic properties if metallic products
detection of laminar discontinuities in heavy plate
measurement of thickness of thin plate
Generally, the best ultrasonic testing method for detecting discontinuities oriented along the fusion zone in a welded plate is:
an angle-beam contact method using surface waves
a contact test using a straight longitudinal wave
an immersion test using surface waves
an angle-beam method using shear waves
In an ultrasonic instrument, the number of pulses produced by an instrument in a given period of time is known as the:
pulse length of the instrument
pulse recovery time
frequency
pulse repetition rate
In a liquid medium, the only mode of vibration that can exist is:
Longitudinal
shear
both A and B above
surface
In a basic pulse-echo ultrasonic instrument, the component that produces the time base line is called a:
sweep circuit
receiver
pulsed
synchronizer
In a basic pulse-echo ultrasonic instrument, the component that produces visible signals on the CRT which are used to measure distance is called a:
sweep circuit
marker circuit
receiver circuit
synchronizer
Most basic pulse-echo ultrasonic instruments use:
automatic read-out equipment
an A-scan presentation
a B-scan presentation
a C-scan presentation
The incident angles at which 90ø refraction of longitudinal and shear waves occurs are called:
the normal angles of incidence
the critical angles
the angles of maximum reflection
none of the above
In contact testing, shear waves can be induced in the test material by:
placing an X-cut crystal directory on the surface of the materials, and coupling through a film of oil
using two transducers on opposite sides of the test specimen
placing a spherical acoustic lens on the face of the transducer
using a transducer mounted on a plastic wedge so that sound enters the part at an angle
The acoustic impedance is:
used to calculate the angle of reflection
the product of the density of the material and the velocity of sound in the material
found by Snell’s law
used to determine resonance values
A hole produced during the solidification of metal due to escaping gases is called:
a burst
a cold shut
a flaking
a blow hole
The equation describing wavelength in terms of velocity and frequency is:
wavelength = velocity x frequency
wavelength = z (frequency x velocity)
wavelength = velocity / frequency
wavelength = frequency / velocity
Of the piezoelectric materials listed below, the most efficient sound transmitter is:
lithium sulfate
quartz
barium titanate
silver oxide
Of the piezoelectric materials listed below, the most efficient sound receiver is:
lithium sulfate
quartz
barium titanate
silver oxide
Beam divergence is a function of the dimensions of the crystal and the wavelength of the beam transmitted through a medium, and it:
increases if the frequency or crystal diameter is decreased
decreases if the frequency or crystal diameter is decreased
increases if the frequency is increased and crystal diameter is decreased
decreases if the frequency is increased and crystal diameter is decreased
The wavelength of an ultrasonic wave is:
directly proportional to velocity and frequency
directly proportional to velocity and inversely proportional to frequency
inversely proportional to velocity and directly proportional to frequency
equal to the product of velocity and frequency
The resolving power of a search unit is directly proportional to its:
diameter
bandwidth
pulse repetition
none of the above
Which or the following frequencies would probably result in the greatest amount of attenuation losses?
1.0 MHz
2.25 MHz
5 MHz
10 MHz
Low frequency sound waves are not generally used to test thin materials because of:
the rapid attenuation of low frequency sound
incompatible wavelengths
poor near-surface resolution
none of the above will actually limit such a test
When using two separate search units (one a transmitter, the other a receiver), the most efficient combination would be:
a quartz transmitter and a barium titanate receiver
a barium titanate transmitter and a lithium sulfate receiver
a lithium sulfate transmitter and a barium titanate receiver
a barium titanate transmitter and a quartz receiver
In Weld testing, the most commonly used transducer is:
straight beam
dual crystal
angle beam
single crystal
The angle of incidence is:
greater than the angle or reflection
less than the angle or reflection
not related to the angle or reflection
equal the angle or reflection
Which of the following frequencies will produce the shortest wavelength?
1.0 MHz
10 MHz
25 MHz
5.0 MHz
“100,000 cycles per second” can be written:
10 kHz
100 MHz
100 kHz
0.1 kHz
