PCN NDT Ultrasonic Testing Level 2 Exam

Which of the following describes the relationship between ultrasonic wave velocity (V), frequency (f), and wavelength (λ)?

• AV = f / λ
• Bf = V * λ
• Cλ = V * f
• DV = f * λ

What is the primary characteristic that distinguishes a longitudinal wave from a shear (transverse) wave?

• AThe frequency of the wave.
• BThe amplitude of the wave.
• CThe direction of particle motion relative to wave propagation.
• DThe medium through which the wave travels.

What happens to an ultrasonic wave when it encounters an interface between two materials with significantly different acoustic impedances?

• AThe wave passes through unimpeded.
• BThe wave is entirely absorbed by the interface.
• CA significant portion of the wave is reflected.
• DThe wave's frequency dramatically increases.

According to Snell's Law, when an ultrasonic wave passes from one medium to another at an angle, what can occur in addition to refraction?

• AThe wave's frequency changes.
• BThe wave's amplitude increases.
• CMode conversion (e.g., longitudinal to shear wave).
• DThe wave's velocity remains constant.

What is the term for the decrease in ultrasonic wave intensity as it propagates through a material?

• ARefraction
• BDiffraction
• CAttenuation
• DReflection

What phenomenon causes the ultrasonic beam to converge and diverge, with variations in sound pressure, within the near field region directly in front of the transducer?

• ASnell's Law
• BDiffraction and interference
• CAcoustic impedance mismatch
• DAttenuation

Which of the following material properties primarily determines the velocity of an ultrasonic wave in a solid material?

• ADensity and electrical conductivity
• BHardness and ductility
• CElastic modulus (stiffness) and density
• DMagnetic permeability and thermal conductivity

What is the principle by which an ultrasonic transducer converts electrical energy into mechanical vibrations and vice versa?

• APhotoelectric effect
• BHall effect
• CPiezoelectric effect
• DThermoelectric effect

Which factor is primarily responsible for improving the axial (depth) resolution in ultrasonic testing?

• ADecreasing transducer frequency
• BIncreasing pulse duration
• CUsing a broader bandwidth (shorter pulse length)
• DIncreasing the beam diameter

What type of ultrasonic wave propagates along the surface of a material, with its amplitude rapidly decreasing with depth from the surface?

• ALongitudinal wave
• BShear wave
• CRayleigh wave (surface wave)
• DLamb wave (plate wave)

Which of the following best describes Lamb waves?

• AWaves that propagate only in liquids.
• BWaves that travel through thick materials with uniform velocity.
• CGuided waves that propagate in plates where thickness is comparable to the wavelength.
• DNon-dispersive waves used for highly precise depth measurements.

The reflection coefficient at an interface between two materials depends on which of the following?

• AThe angle of incidence only.
• BThe difference in their acoustic impedances.
• CThe frequency of the ultrasonic wave only.
• DThe temperature of the materials only.

What is diffraction in the context of ultrasonic wave propagation?

• AThe bending of waves as they pass from one medium to another.
• BThe spreading out of waves as they pass through an aperture or around an obstacle.
• CThe bouncing back of waves from an interface.
• DThe loss of wave energy due to absorption.

The pulse-echo ultrasonic technique relies on which fundamental wave property?

• ADispersion
• BMode conversion
• CReflection
• DDiffraction

When an ultrasonic longitudinal wave enters a material from a couplant at the first critical angle, what happens to the refracted longitudinal wave?

• AIt travels perpendicular to the interface.
• BIt is entirely reflected, with no transmission.
• CIt travels parallel to the interface.
• DIts amplitude significantly increases.

How does increasing the grain size of a material generally affect ultrasonic attenuation?

• AIt decreases attenuation due to less scattering.
• BIt has no significant effect on attenuation.
• CIt increases attenuation due to increased scattering.
• DIt increases attenuation due to increased absorption.

What is the general trade-off when selecting a higher frequency transducer for ultrasonic testing?

• AImproved penetration depth at the expense of resolution.
• BImproved resolution at the expense of penetration depth.
• CNo change in either penetration or resolution.
• DImproved signal-to-noise ratio with reduced sensitivity.

In an angle beam transducer (probe), the active element is usually oriented to generate which type of wave in the test material?

• ARayleigh waves only.
• BLongitudinal waves at a steep angle.
• CShear waves at a specific refracted angle.
• DCompressional waves perpendicular to the surface.

What is the primary purpose of the backing material in an ultrasonic transducer?

• ATo protect the transducer element from damage.
• BTo focus the ultrasonic beam.
• CTo damp the vibrations of the piezoelectric element and shorten the pulse length.
• DTo provide an electrical connection to the element.

Which term refers to the amount of energy passing through a unit area per unit time, directly related to the 'strength' of the ultrasonic wave?

• AWavelength
• BFrequency
• CAcoustic Impedance
• DIntensity

What is the primary purpose of calibrating an ultrasonic flaw detector?

• ATo extend the battery life of the equipment.
• BTo ensure accurate and reliable measurements of defect location and size.
• CTo change the frequency of the ultrasonic transducer.
• DTo reduce the overall weight of the flaw detector.

Which of the following is NOT a standard calibration block used in ultrasonic testing?

• AIIW (International Institute of Welding) Block V1
• BDSC (Distance/Sensitivity/Characteristic) Block
• CASTM E164 Calibration Block
• DMetric Weight Block

What is typically adjusted during a 'distance calibration' or 'range calibration' procedure?

• AThe frequency of the ultrasonic transducer.
• BThe velocity of sound in the test material on the flaw detector.
• CThe physical size of the transducer crystal.
• DThe pulse repetition frequency (PRF) of the instrument.

Why is it important to perform sensitivity calibration regularly during ultrasonic inspection?

• ATo reduce the power consumption of the ultrasonic instrument.
• BTo ensure that small, relevant defects are consistently detectable.
• CTo prevent electromagnetic interference from affecting the readings.
• DTo change the propagation mode of the ultrasonic waves.

When calibrating for an angle beam transducer, what is the significance of the 'refracted angle'?

• AIt determines the transducer's physical dimensions.
• BIt is the angle at which the sound beam travels through the test material.
• CIt is the angle at which the sound beam hits the test surface.
• DIt represents the maximum achievable gain setting.

What is the primary function of a delay line in a contact transducer, and how does it affect calibration?

• ATo increase the transducer's operating frequency, requiring a different calibration block.
• BTo improve acoustic coupling by filling surface irregularities, simplifying sensitivity c…
• CTo provide an acoustic stand-off, separating the initial pulse from the first material ec…
• DTo change the beam divergence angle, necessitating specific angle beam calibration.

When performing a 'linearity' check, what characteristic of the ultrasonic instrument is being evaluated?

• AThe instrument's ability to maintain constant gain across different frequencies.
• BThe accuracy of the time-base display for distance measurements.
• CThe proportional response of the display height to changes in signal amplitude.
• DThe transducer's ability to generate a perfectly parallel beam.

What is the purpose of setting up a Distance Amplitude Correction (DAC) curve?

• ATo compensate for the varying speed of sound in different materials.
• BTo correct for material attenuation and beam spread, ensuring consistent flaw sizing at d…
• CTo adjust the transducer's operating frequency to match the material thickness.
• DTo calibrate the physical location of the transducer on the test surface.

Before starting any ultrasonic inspection, what is the first essential step related to equipment calibration?

• ASetting the alarm gates for flaw detection.
• BApplying couplant to the test surface.
• CVerifying the instrument's calibration and functionality on a reference block.
• DDetermining the exact chemical composition of the test material.

What could be the consequence of using an improperly calibrated ultrasonic flaw detector?

• AIncreased battery life of the equipment.
• BReduced need for couplant during inspection.
• CInaccurate defect sizing and location, potentially leading to critical flaws being missed…
• DFaster scanning speed and improved productivity.

What is 'dead zone' in ultrasonic testing, and how does it relate to calibration and transducer selection?

• AIt refers to the maximum depth an ultrasonic wave can penetrate, influencing range calibr…
• BIt is the area directly beneath the transducer where signals cannot be resolved, impactin…
• CIt is the region where the sound beam is perfectly focused, simplifying angle beam calibr…
• DIt describes the operating temperature range of the transducer, affecting gain calibratio…

Which parameter is adjusted during the 'material velocity' calibration step on an ultrasonic flaw detector?

• ADisplay sweep speed.
• BPulse repetition frequency.
• CSound velocity setting.
• DTransducer frequency.

Why is the temperature of the calibration block and test material important during ultrasonic calibration?

• AIt affects the electrical impedance of the transducer.
• BIt influences the speed of sound and material attenuation, requiring adjustments for accu…
• CIt changes the physical dimensions of the calibration block, altering reference points.
• DIt impacts the viscosity of the couplant, making it harder to apply.

What does a 'probe delay' or 'zero offset' setting compensate for in an ultrasonic flaw detector?

• AThe time taken for sound to travel through the test material to the first defect.
• BThe inherent time delay in the transducer and cable, and the couplant layer thickness.
• CThe duration of the initial pulse generated by the instrument.
• DThe time required for the instrument's display to update.

When using an angle beam probe, how is the 'beam index point' (BIP) or 'exit point' determined during calibration?

• ABy measuring the distance from the front of the probe to the first echo.
• BBy moving the probe on a calibration block (e.g., IIW V1) to locate the peak echo from a…
• CBy calculating it based on the transducer's frequency and element size.
• DBy visually inspecting the probe's wedge for wear.

What is the consequence of an incorrect 'zero offset' setting on a flaw detector?

• AThe transducer will generate a weaker ultrasonic pulse.
• BAll measured depths and distances will be consistently incorrect.
• CThe display screen will flicker intermittently.
• DThe instrument will automatically switch to a lower frequency.

Which type of calibration block is primarily used for establishing sensitivity and often checking probe exit point and refracted angle for angle beam probes?

• AStep Wedge Block
• BResolution Calibration Block
• CIIW (International Institute of Welding) Block V1
• DArea Amplitude Block

What is the significance of the 'gain' control during ultrasonic calibration and inspection?

• AIt adjusts the pulse repetition frequency.
• BIt controls the amplification of the received ultrasonic signals.
• CIt changes the transducer's operating frequency.
• DIt modifies the display's sweep speed.

According to most NDT standards, how often should system calibration be verified during a prolonged inspection?

• AOnly once at the beginning of the inspection.
• BEvery 4 hours or at the start/end of each shift, whichever is more frequent, or when equi…
• COnly if the operator suspects a malfunction.
• DOnce a day, regardless of shift length or setting changes.

What is the primary function of a calibration certificate for an ultrasonic flaw detector and transducer?

• ATo provide a detailed history of all previous inspections performed with the equipment.
• BTo confirm that the equipment meets specified performance standards and traceability to n…
• CTo list the recommended couplants for use with the transducer.
• DTo serve as a warranty document for the equipment's lifespan.

In the pulse-echo ultrasonic testing technique, how is the presence of a discontinuity typically detected?

• ABy measuring the time taken for the sound to travel from the transducer through the mater…
• BBy observing a reduction in the amplitude of the through-transmitted sound wave.
• CBy detecting a reflected sound wave from the discontinuity before the backwall echo.
• DBy analyzing the shift in the frequency of the sound wave passing through the material.

Which ultrasonic testing technique uses two transducers, one for transmitting and one for receiving, placed on opposite sides of the test piece?

• APulse-echo technique
• BImmersion testing
• CTime-of-Flight Diffraction (TOFD)
• DThrough-transmission technique

What is a primary advantage of immersion ultrasonic testing compared to contact testing?

• AIt requires less specialized equipment.
• BIt allows for faster scanning speeds over large areas.
• CIt eliminates the need for any coupling medium.
• DIt is more suitable for very rough or irregular surfaces.

Straight beam (normal incidence) ultrasonic testing is primarily used to detect discontinuities oriented in which direction relative to the test surface?

• APerpendicular to the sound beam.
• BParallel to the sound beam.
• CAt an angle greater than 45 degrees to the sound beam.
• DOnly surface-breaking discontinuities.

Which type of ultrasonic transducer is best suited for detecting discontinuities that are oriented obliquely or perpendicular to the material surface, such as those found in welds?

• AStraight beam (0-degree) transducer
• BDual element transducer
• CAngle beam transducer
• DImmersion transducer

Surface waves (Rayleigh waves) in ultrasonic testing are characterized by their ability to travel along the surface of a material. What is a common application for surface waves?

• ADetecting internal laminations in thick plates.
• BMeasuring the thickness of a component from one side.
• CDetecting surface-breaking cracks and near-surface discontinuities.
• DInspecting anisotropic materials with complex grain structures.

Lamb waves are a type of guided wave used in ultrasonic testing. What is a key characteristic that makes them suitable for long-range inspection?

• AThey only propagate as longitudinal waves.
• BThey are confined to the near-surface region of thick components.
• CThey can propagate over long distances in plate-like structures with minimal attenuation.
• DTheir velocity is independent of the plate thickness.