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ASNT Phased Array Level II Ultimate Exam, Exams of Technology

Technology

The ASNT Phased Array Level II Ultimate Exam is a specialized preparation solution designed for technicians and inspectors working with phased array ultrasonic testing technologies. This comprehensive exam covers phased array principles, equipment calibration, beam steering, imaging techniques, defect characterization, inspection procedures, code compliance, and data interpretation. Candidates gain practical knowledge through scenario-based practice questions, detailed explanations, and exam-style assessments that mirror real-world inspection applications. Ideal for NDT professionals seeking advanced ultrasonic testing certification, this ultimate exam improves technical accuracy, inspection competency, and certification confidence.

Typology: Exams

2025/2026

Available from 05/08/2026

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ASNT Phased Array Level II Ultimate Exam

QUESTION 1. **WHICH WAVE MODE IS MOST SENSITIVE TO PLANAR CRACKS ORIENTED

PERPENDICULAR TO THE SURFACE IN AUSTENITIC STEEL?**

A) LONGITUDINAL WAVE

B) SHEAR WAVE

C) SURFACE WAVE

D) PLATE WAVE

ANSWER: B

EXPLANATION: SHEAR WAVES POLARIZE PARTICLE MOTION PARALLEL TO THE SURFACE, MAKING THEM

ESPECIALLY SENSITIVE TO CRACKS THAT OPEN IN THE SHEAR DIRECTION, SUCH AS PLANAR CRACKS

PERPENDICULAR TO THE INSPECTED SURFACE.

QUESTION 2. **SNELL’S LAW FOR ULTRASONIC WAVES AT AN INTERFACE IS EXPRESSED AS:**

A) SINΘ₁ / V₁ = SINΘ₂ / V₂

B) SINΘ₁ * V₁ = SINΘ₂ * V₂

C) SINΘ₁ / C₁ = SINΘ₂ / C₂

D) SINΘ₁ * C₁ = SINΘ₂ * C₂

ANSWER: A

EXPLANATION: SNELL’S LAW RELATES THE INCIDENT AND REFRACTED ANGLES TO THE VELOCITIES (OR

SOUND SPEEDS) OF THE TWO MEDIA: SINΘ₁ / V₁ = SINΘ₂ / V₂.

QUESTION 3. **IN A PHASED‑ARRAY PROBE, THE “PITCH” REFERS TO:**

A) THE DISTANCE BETWEEN THE FRONT FACE OF THE PROBE AND THE TEST PIECE

B) THE CENTER‑TO‑CENTER SPACING OF ADJACENT ACTIVE ELEMENTS

C) THE FREQUENCY BANDWIDTH OF THE PROBE

D) THE DELAY TIME APPLIED TO EACH ELEMENT FOR FOCUSING

ANSWER: B

EXPLANATION: PITCH IS THE CENTER‑TO‑CENTER SPACING OF ADJACENT TRANSDUCER ELEMENTS AND

DIRECTLY INFLUENCES GRATING‑LOBE FORMATION.

QUESTION 4. **GRATING LOBES BECOME A CONCERN WHEN THE ELEMENT PITCH EXCEEDS:**

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QUESTION 1. **WHICH WAVE MODE IS MOST SENSITIVE TO PLANAR CRACKS ORIENTED

PERPENDICULAR TO THE SURFACE IN AUSTENITIC STEEL?**

A) LONGITUDINAL WAVE

B) SHEAR WAVE

C) SURFACE WAVE

D) PLATE WAVE

ANSWER: B

EXPLANATION: SHEAR WAVES POLARIZE PARTICLE MOTION PARALLEL TO THE SURFACE, MAKING THEM

ESPECIALLY SENSITIVE TO CRACKS THAT OPEN IN THE SHEAR DIRECTION, SUCH AS PLANAR CRACKS

PERPENDICULAR TO THE INSPECTED SURFACE.

QUESTION 2. SNELL’S LAW FOR ULTRASONIC WAVES AT AN INTERFACE IS EXPRESSED AS:

A) SINΘ₁ / V₁ = SINΘ₂ / V₂

B) SINΘ₁ * V₁ = SINΘ₂ * V₂

C) SINΘ₁ / C₁ = SINΘ₂ / C₂

D) SINΘ₁ * C₁ = SINΘ₂ * C₂

ANSWER: A

EXPLANATION: SNELL’S LAW RELATES THE INCIDENT AND REFRACTED ANGLES TO THE VELOCITIES (OR

SOUND SPEEDS) OF THE TWO MEDIA: SINΘ₁ / V₁ = SINΘ₂ / V₂.

QUESTION 3. IN A PHASED‑ARRAY PROBE, THE “PITCH” REFERS TO:

A) THE DISTANCE BETWEEN THE FRONT FACE OF THE PROBE AND THE TEST PIECE

B) THE CENTER‑TO‑CENTER SPACING OF ADJACENT ACTIVE ELEMENTS

C) THE FREQUENCY BANDWIDTH OF THE PROBE

D) THE DELAY TIME APPLIED TO EACH ELEMENT FOR FOCUSING

ANSWER: B

EXPLANATION: PITCH IS THE CENTER‑TO‑CENTER SPACING OF ADJACENT TRANSDUCER ELEMENTS AND

DIRECTLY INFLUENCES GRATING‑LOBE FORMATION.

QUESTION 4. GRATING LOBES BECOME A CONCERN WHEN THE ELEMENT PITCH EXCEEDS:

A) 0.5 Λ IN THE TEST MATERIAL

B) Λ IN THE TEST MATERIAL

C) 1.5 Λ IN THE TEST MATERIAL

D) 2 Λ IN THE TEST MATERIAL

ANSWER: A

EXPLANATION: TO AVOID GRATING LOBES, THE PITCH SHOULD BE ≤ 0.5 Λ (WAVELENGTH IN THE TEST

MATERIAL) AT THE HIGHEST STEERING ANGLE.

QUESTION 5. THE PRIMARY PURPOSE OF A WEDGE IN PAUT IS TO:

A) INCREASE THE FREQUENCY OF THE TRANSMITTED WAVE

B) MATCH THE ACOUSTIC IMPEDANCE OF THE PROBE TO THE TEST MATERIAL

C) PROVIDE A CONTROLLED DELAY PATH FOR EACH ELEMENT

D) CONVERT SHEAR WAVES TO LONGITUDINAL WAVES ONLY

ANSWER: C

EXPLANATION: A WEDGE ADDS A KNOWN PATH LENGTH (DELAY) AND MAY ALSO CHANGE WAVE

MODE; ITS GEOMETRY DETERMINES THE TIME DELAY FOR EACH ELEMENT.

QUESTION 6. **WHICH OF THE FOLLOWING PROBE TYPES CONTAINS A TWO‑DIMENSIONAL MATRIX OF

ELEMENTS?**

A) LINEAR ARRAY

B) ANNULAR ARRAY

C) MATRIX ARRAY

D) DUAL‑MODE ARRAY

ANSWER: C

EXPLANATION: A MATRIX ARRAY HAS ROWS AND COLUMNS OF ELEMENTS, ENABLING ELECTRONIC

STEERING IN BOTH AZIMUTH AND ELEVATION.

QUESTION 7. WHEN PERFORMING A SECTORIAL (S‑SCAN) IN PAUT, THE BEAM IS:

A) STEERED THROUGH A RANGE OF ANGLES WHILE DEPTH IS FIXED

B) SCANNED LATERALLY ACROSS THE SPECIMEN SURFACE

ANSWER: B

EXPLANATION: THE IIW CONTAINS BOTH A LONGITUDINAL AND A SHEAR WIRE, ALLOWING

VERIFICATION OF VELOCITY AND GAIN SETTINGS FOR BOTH WAVE MODES.

QUESTION 11. **WHICH PARAMETER DIRECTLY INFLUENCES THE NEAR‑FIELD LENGTH (NF) OF A PAUT

PROBE?**

A) ELEMENT PITCH

B) FREQUENCY AND APERTURE SIZE

C) COUPLANT TEMPERATURE

D) PRF SETTING

ANSWER: B

EXPLANATION: NF ≈ D² / (4Λ), WHERE D IS APERTURE SIZE AND Λ IS WAVELENGTH; THUS FREQUENCY

(WHICH DETERMINES Λ) AND APERTURE SIZE ARE KEY.

QUESTION 12. THE “ACTIVE APERTURE” OF A PHASED ARRAY REFERS TO:

A) THE TOTAL PHYSICAL SIZE OF THE PROBE HOUSING

B) THE NUMBER OF ELEMENTS THAT ARE SIMULTANEOUSLY EXCITED FOR A GIVEN FOCAL LAW

C) THE DISTANCE BETWEEN THE PROBE AND THE TEST SURFACE

D) THE FREQUENCY BANDWIDTH OF THE PROBE

ANSWER: B

EXPLANATION: ACTIVE APERTURE IS THE SUBSET OF ELEMENTS THAT ARE ENERGIZED FOR A SPECIFIC

BEAM STEERING/FOCUSING OPERATION.

QUESTION 13. WHEN USING A DUAL‑MATRIX ARRAY (DMA), THE MAIN ADVANTAGE IS:

A) ABILITY TO GENERATE BOTH LONGITUDINAL AND SHEAR WAVES WITHOUT A WEDGE

B) HIGHER PRF THAN SINGLE‑MATRIX PROBES

C) SIMPLIFIED CALIBRATION DUE TO SINGLE‑ELEMENT OPERATION

D) REDUCED NEED FOR COUPLING MATERIAL

ANSWER: A

EXPLANATION: DMA PROBES CONTAIN SEPARATE MATRICES FOR LONGITUDINAL AND SHEAR WAVE

GENERATION, ELIMINATING THE NEED FOR SEPARATE WEDGES.

QUESTION 14. WHICH SCAN TYPE PROVIDES A TOP‑DOWN PLAN VIEW OF THE INSPECTED AREA?

A) A‑SCAN

B) B‑SCAN

C) C‑SCAN

D) D‑SCAN

ANSWER: C

EXPLANATION: A C‑SCAN DISPLAYS A PLAN‑VIEW (X‑Y) IMAGE, MAPPING AMPLITUDE OR OTHER

PARAMETERS ACROSS THE SCANNED SURFACE.

QUESTION 15. A “COMPOUND SCAN” IN PAUT COMBINES:

A) MULTIPLE FREQUENCIES IN A SINGLE ACQUISITION

B) LINEAR (E‑SCAN) MOVEMENT WITH SECTORIAL (S‑SCAN) STEERING

C) BOTH LONGITUDINAL AND SHEAR WAVE DATA IN ONE VIEW

D) MANUAL AND AUTOMATED SCANNING SIMULTANEOUSLY

ANSWER: B

EXPLANATION: COMPOUND SCANS MERGE LINEAR TRANSLATION AND ANGULAR STEERING TO

IMPROVE COVERAGE AND DEFECT DETECTABILITY.

QUESTION 16. THE PRIMARY REASON FOR USING A CONTOURED WEDGE IN PIPE INSPECTION IS TO:

A) INCREASE THE PROBE’S OPERATING FREQUENCY

B) MAINTAIN A CONSTANT ANGLE OF INCIDENCE AROUND THE PIPE’S CURVATURE

C) REDUCE THE NEED FOR COUPLANT ON THE OUTER SURFACE

D) ELIMINATE MODE CONVERSION AT THE PIPE WALL

ANSWER: B

EXPLANATION: A CONTOURED WEDGE MATCHES THE PIPE’S CURVATURE, KEEPING THE INCIDENT

ANGLE CONSISTENT AS THE PROBE MOVES AROUND THE CIRCUMFERENCE.

A) COUPLANT LOSS AT THE FLAW LOCATION

B) BEAM DIFFRACTION AROUND A LARGE DEFECT

C) INCORRECT ACG SETTINGS FOR THE STEERING ANGLE USED

D) GRATING LOBE INTERFERENCE FROM NEIGHBORING ELEMENTS

ANSWER: C

EXPLANATION: IMPROPER ANGLE‑CORRECTED GAIN CAN CAUSE AMPLITUDE VARIATIONS ACROSS THE

SCAN, PRODUCING A HALO EFFECT AROUND INDICATIONS.

QUESTION 21. THE “6 DB DROP” METHOD FOR FLAW SIZING ASSUMES:

A) THE FLAW SIZE EQUALS THE DISTANCE BETWEEN THE POINTS WHERE THE SIGNAL DROPS 6 DB

BELOW THE PEAK AMPLITUDE

B) THE FLAW DEPTH IS HALF THE DISTANCE BETWEEN THE 6 DB POINTS

C) THE FLAW WIDTH IS TWICE THE DISTANCE BETWEEN THE 6 DB POINTS

D) THE FLAW LENGTH IS PROPORTIONAL TO THE SQUARE OF THE 6 DB DISTANCE

ANSWER: A

EXPLANATION: THE 6 DB DROP METHOD DEFINES FLAW DIMENSIONS BY MEASURING THE LATERAL

DISTANCE BETWEEN POINTS WHERE THE ECHO AMPLITUDE FALLS 6 DB FROM THE PEAK.

QUESTION 22. **WHICH OF THE FOLLOWING CODES IS MOST COMMONLY REFERENCED FOR PAUT

ACCEPTANCE CRITERIA IN WELD INSPECTION OF PRESSURE VESSELS?**

A) API 1104

B) ASTM E

C) ISO 9712

D) IEC 60545

ANSWER: A

EXPLANATION: API 1104 PROVIDES DETAILED ACCEPTANCE CRITERIA FOR ULTRASONIC TESTING OF

WELDS IN PRESSURE VESSELS, WIDELY USED IN INDUSTRY.

QUESTION 23. **A “PULSE‑ON‑POSITION” RECORDING METHOD DIFFERS FROM “TIME‑BASED”

RECORDING BECAUSE:**

A) IT STORES DATA ONLY WHEN THE PROBE IS STATIONARY

B) IT TAGS EACH A‑SCAN WITH THE EXACT SPATIAL COORDINATE OF THE PROBE AT THE MOMENT OF

PULSE EMISSION

C) IT USES A HIGHER PRF TO CAPTURE MORE DATA POINTS PER SECOND

D) IT ELIMINATES THE NEED FOR AN ENCODER ON THE SCANNER

ANSWER: B

EXPLANATION: PULSE‑ON‑POSITION LINKS EACH ECHO TO A PRECISE PROBE LOCATION, ENABLING

ACCURATE MAPPING WITHOUT RELYING SOLELY ON TIME‑BASED INTERPOLATION.

QUESTION 24. MAXIMUM SCAN SPEED FOR A GIVEN PRF IS LIMITED BY:

A) THE PROBE’S ELEMENT PITCH

B) THE DESIRED LATERAL RESOLUTION (PIXEL SPACING)

C) THE ACOUSTIC IMPEDANCE OF THE COUPLANT

D) THE WEDGE MATERIAL COMPOSITION

ANSWER: B

EXPLANATION: SCAN SPEED MUST ENSURE THAT SUCCESSIVE A‑SCANS ARE SPACED NO FARTHER APART

THAN THE REQUIRED LATERAL RESOLUTION; HIGHER PRF ALLOWS FASTER TRAVEL.

QUESTION 25. **WHEN PERFORMING AN AUTOMATED SCAN, A “MISSING LINE” IN THE DATA SET MOST

LIKELY INDICATES:**

A) A COUPLANT FAILURE ON THAT LINE

B) AN ENCODER MIS‑COUNT OR SLIP

C) EXCESSIVE GAIN CAUSING SIGNAL SATURATION

D) THE PRESENCE OF A LARGE FLAW THAT BLOCKED THE BEAM

ANSWER: B

EXPLANATION: MISSING LINES ARE TYPICALLY CAUSED BY ENCODER ERRORS WHERE A TRAVEL

INCREMENT WAS NOT RECORDED, LEADING TO GAPS IN THE IMAGE.

QUESTION 26. **IN A PAUT INSPECTION OF A THICK CARBON STEEL PLATE, WHICH FOCAL LAW WOULD

BEST IMPROVE DETECTION OF DEEP‑LYING PLANAR CRACKS?**

A) WIDE‑ANGLE SECTORIAL SCAN WITH SHALLOW FOCUS

B) NARROW‑ANGLE LINEAR SCAN WITH DEEP FOCUS

D) LOWER POWER CONSUMPTION

ANSWER: B

EXPLANATION: MORE ELEMENTS (BOTH TOTAL AND PER GROUP) PROVIDE FINER CONTROL OVER BEAM

STEERING AND FOCUSING, IMPROVING ANGULAR RESOLUTION.

QUESTION 30. **THE “FAR‑FIELD” DISTANCE (FRAUNHOFER ZONE) FOR A PHASED ARRAY IS

APPROXIMATED BY:**

A) D² / (4Λ)

B) D / Λ

C) 2D² / Λ

D) Λ / (2D)

ANSWER: A

EXPLANATION: THE FAR‑FIELD (OR RAYLEIGH) DISTANCE IS GIVEN BY D²/(4Λ), WHERE D IS THE

APERTURE SIZE AND Λ IS WAVELENGTH.

QUESTION 31. **IN A SHEAR‑WAVE PAUT INSPECTION, THE SHEAR WEDGE ANGLE IS TYPICALLY LARGER

THAN THE LONGITUDINAL WEDGE ANGLE BECAUSE:**

A) SHEAR WAVES TRAVEL SLOWER, REQUIRING A LARGER PHYSICAL DEFLECTION TO ACHIEVE THE SAME

REFRACTION ANGLE

B) SHEAR WEDGES ARE MADE OF SOFTER MATERIAL

C) THE PROBE’S ELEMENT SPACING IS GREATER FOR SHEAR MODE

D) SHEAR WAVES NEED A HIGHER PRF TO PROPAGATE

ANSWER: A

EXPLANATION: SINCE SHEAR WAVE SPEED IS LOWER, A LARGER WEDGE ANGLE IS NEEDED TO OBTAIN

THE SAME REFRACTION ANGLE AS A LONGITUDINAL WAVE.

QUESTION 32. **DURING A PAUT SCAN OF A PIPE, THE “FLAW ANGLE” DISPLAYED ON THE S‑SCAN IS

MEASURED RELATIVE TO:**

A) THE PROBE FACE NORMAL

B) THE PIPE’S AXIAL DIRECTION

C) THE RADIAL DIRECTION (NORMAL TO PIPE SURFACE)

D) THE CIRCUMFERENTIAL DIRECTION

ANSWER: C

EXPLANATION: FLAW ANGLE ON AN S‑SCAN IS REFERENCED TO THE RADIAL DIRECTION (NORMAL TO

THE PIPE WALL), INDICATING THE ORIENTATION OF THE DEFECT RELATIVE TO THE SURFACE.

QUESTION 33. **WHICH OF THE FOLLOWING IS THE MOST APPROPRIATE METHOD TO VERIFY THAT A

PAUT SYSTEM’S ACG IS CORRECTLY APPLIED ACROSS A ±30° STEERING RANGE?**

A) SCAN A CALIBRATED SIDE‑GATE BLOCK AT MULTIPLE ANGLES AND COMPARE ECHO AMPLITUDES

B) MEASURE THE PRF AT EACH ANGLE AND ADJUST ACCORDINGLY

C) USE A HIGHER GAIN SETTING FOR THE HIGHEST STEERING ANGLE ONLY

D) CHANGE THE WEDGE MATERIAL TO ONE WITH HIGHER ACOUSTIC IMPEDANCE

ANSWER: A

EXPLANATION: A SIDE‑GATE BLOCK PROVIDES A KNOWN REFLECTOR; SCANNING IT AT VARIOUS ANGLES

ALLOWS VERIFICATION THAT ACG YIELDS UNIFORM AMPLITUDE.

QUESTION 34. **IN A PAUT TECHNIQUE SHEET, THE “GATE START” AND “GATE STOP” VALUES ARE

TYPICALLY EXPRESSED IN:**

A) MILLIMETERS FROM THE PROBE SURFACE

B) MICROSECONDS OF TRAVEL TIME

C) DEGREES OF STEERING ANGLE

D) HERTZ OF FREQUENCY SHIFT

ANSWER: B

EXPLANATION: GATES ARE DEFINED BY START AND STOP TIMES (μS) CORRESPONDING TO SPECIFIC DEPTHS IN THE MATERIAL. QUESTION 35. WHEN A PAUT INSPECTION SHOWS A “DOUBLE‑ECHO” PATTERN ON THE A‑SCAN, THE MOST COMMON CAUSE IS: MULTIPLE REFLECTIONS BETWEEN THE PROBE FACE AND THE TEST SURFACE B) A FLAW WITH TWO PARALLEL FACES C) MODE CONVERSION FROM LONGITUDINAL TO SHEAR AND BACK D) GRATING LOBE OVERLAPPING THE MAIN BEAM

EXPLANATION: THE NEAR‑FIELD REGION EXHIBITS COMPLEX INTERFERENCE PATTERNS AND REDUCED

RESOLUTION, CREATING A DEAD‑ZONE WHERE DEFECTS MAY BE MISSED.

QUESTION 39. **WHEN CONVERTING A CONVENTIONAL UT TECHNIQUE TO PAUT, WHICH PARAMETER

MUST BE RE‑CALIBRATED FIRST?**

A) PRF

B) VELOCITY IN THE TEST MATERIAL

C) COUPLANT VISCOSITY

D) PROBE ELEMENT PITCH

ANSWER: B

EXPLANATION: VELOCITY CALIBRATION IS ESSENTIAL BECAUSE FOCAL LAWS, TIME‑GAIN, AND DEPTH

CALCULATIONS ALL DEPEND ON ACCURATE SOUND SPEED.

QUESTION 40. **A “COMPOUND‑SCAN” THAT COMBINES SHEAR‑WAVE LINEAR SCANNING WITH

LONGITUDINAL‑WAVE SECTORIAL SCANNING IS PRIMARILY USED TO:**

A) REDUCE INSPECTION TIME BY HALF

B) DETECT BOTH SURFACE‑BREAKING CRACKS AND VOLUMETRIC INCLUSIONS IN A SINGLE PASS

C) ELIMINATE THE NEED FOR A WEDGE ALTOGETHER

D) INCREASE THE PRF BEYOND INSTRUMENT LIMITS

ANSWER: B

EXPLANATION: USING BOTH WAVE MODES AND SCAN TYPES PROVIDES COMPLEMENTARY SENSITIVITY

TO DIFFERENT DEFECT TYPES.

QUESTION 41. **THE “ELEMENT‑TO‑ELEMENT DELAY” REQUIRED TO STEER A BEAM TO 15° IN A LINEAR

ARRAY IS CALCULATED USING:**

A) ΔT = (PITCH · SINΘ) / C

B) ΔT = (PITCH · COSΘ) / C

C) ΔT = (Λ · SINΘ) / C

D) ΔT = (Λ · COSΘ) / C

ANSWER: A

EXPLANATION: THE REQUIRED TIME DELAY PER ELEMENT FOR STEERING ANGLE Θ IS ΔT = (PITCH · SINΘ)

/ C, WHERE C IS SOUND SPEED IN THE WEDGE.

QUESTION 42. WHICH OF THE FOLLOWING STATEMENTS ABOUT “SIDE‑LOBES” IS CORRECT?

A) SIDE‑LOBES HAVE THE SAME INTENSITY AS THE MAIN LOBE WHEN THE APERTURE IS FULLY OPEN

B) SIDE‑LOBES CAN BE REDUCED BY APPLYING A HANNING WINDOW TO THE ELEMENT EXCITATION

AMPLITUDES

C) SIDE‑LOBES ARE ELIMINATED COMPLETELY BY INCREASING PRF

D) SIDE‑LOBES ONLY APPEAR IN SHEAR‑WAVE MODE

ANSWER: B

EXPLANATION: APPLYING A TAPER (E.G., HANNING WINDOW) TO THE EXCITATION AMPLITUDES

REDUCES SIDE‑LOBE LEVELS BY SMOOTHING THE APERTURE FUNCTION.

QUESTION 43. IN PAUT, THE TERM “DIGITAL BEAMFORMING” REFERS TO:

A) USING ANALOG DELAY LINES TO STEER THE BEAM

B) APPLYING SOFTWARE‑BASED DELAYS AND WEIGHTING AFTER DIGITIZING THE RAW ELEMENT

SIGNALS

C) PHYSICALLY MOVING THE PROBE TO CHANGE THE BEAM DIRECTION

D) CHANGING THE PROBE’S FREQUENCY ON THE FLY

ANSWER: B

EXPLANATION: DIGITAL BEAMFORMING PROCESSES DIGITIZED ELEMENT DATA WITH PROGRAMMABLE

DELAYS AND WEIGHTS TO CREATE THE DESIRED BEAM SHAPE.

QUESTION 44. **WHEN A PAUT INSPECTION OF A STAINLESS‑STEEL WELD SHOWS A “RING‑DOWN”

AFTER THE MAIN ECHO, THE MOST LIKELY CAUSE IS:**

A) EXCESSIVE GAIN CAUSING REVERBERATIONS WITHIN THE PROBE

B) MODE CONVERSION AT THE WELD INTERFACE

C) A LARGE FLAW CAUSING MULTIPLE INTERNAL REFLECTIONS

D) GRATING LOBE INTERFERENCE FROM NEIGHBORING ELEMENTS

ANSWER: A

QUESTION 48. **IN A PAUT INSPECTION OF A CURVED SURFACE, THE “VIRTUAL PROBE” CONCEPT IS

USED TO:**

A) PHYSICALLY BEND THE PROBE TO MATCH THE CURVATURE

B) APPLY SOFTWARE‑BASED GEOMETRIC CORRECTIONS THAT SIMULATE A PROBE MOVING ALONG THE

CURVATURE WHILE THE ACTUAL PROBE REMAINS LINEAR

C) CHANGE THE FREQUENCY TO ACCOMMODATE CURVATURE

D) INCREASE THE WEDGE ANGLE AUTOMATICALLY

ANSWER: B

EXPLANATION: THE VIRTUAL PROBE ALGORITHM TRANSLATES AND ROTATES THE SCAN DATA TO

REPRESENT WHAT WOULD BE OBTAINED IF THE PROBE FOLLOWED THE SURFACE CONTOUR.

QUESTION 49. **WHEN CALIBRATING A PAUT SYSTEM FOR A NEW MATERIAL, THE “VELOCITY

CALIBRATION BLOCK” MUST BE POSITIONED AT:**

A) EXACTLY AT THE FOCAL DEPTH OF THE PROBE

B) AT THE NEAR‑FIELD LIMIT TO MAXIMIZE ECHO STRENGTH

C) AT A KNOWN DISTANCE THAT SPANS THE FULL RANGE OF DEPTHS TO BE INSPECTED

D) DIRECTLY ON THE PROBE FACE TO AVOID WEDGE DELAY ERRORS

ANSWER: C

EXPLANATION: PLACING THE BLOCK AT A KNOWN DISTANCE COVERING THE INSPECTION DEPTH RANGE

ALLOWS ACCURATE VELOCITY DETERMINATION ACROSS THE REQUIRED DEPTH.

QUESTION 50. **A “SECTORIAL‑S‑SCAN” WITH A 60° SWEEP IS PERFORMED ON A 20 MM THICK PLATE.

THE MINIMUM DETECTABLE FLAW HEIGHT IS LIMITED PRIMARILY BY:**

A) THE PRF SETTING

B) THE BEAMWIDTH AT THE DEEPEST FOCUS DEPTH

C) THE ELEMENT PITCH OF THE PROBE

D) THE COUPLANT TEMPERATURE

ANSWER: B

EXPLANATION: AS THE BEAM IS STEERED, ITS LATERAL RESOLUTION (BEAMWIDTH) AT THE DEEPEST

FOCUS DICTATES THE SMALLEST DETECTABLE FLAW HEIGHT.

QUESTION 51. **WHICH OF THE FOLLOWING BEST DESCRIBES THE PURPOSE OF “DYNAMIC RANGE”

SETTING ON A PAUT INSTRUMENT?**

A) IT DEFINES THE MAXIMUM STEERING ANGLE ALLOWED

B) IT SETS THE VOLTAGE AMPLITUDE OF THE TRANSMITTED PULSE

C) IT DETERMINES THE RATIO BETWEEN THE STRONGEST AND WEAKEST SIGNALS DISPLAYED

D) IT CONTROLS THE NUMBER OF ELEMENTS ACTIVATED PER SCAN LINE

ANSWER: C

EXPLANATION: DYNAMIC RANGE IS THE DISPLAY PARAMETER THAT SETS THE AMPLITUDE WINDOW

(E.G., 60 DB) BETWEEN THE BRIGHTEST AND DARKEST ECHOES.

QUESTION 52. **IN A PAUT INSPECTION OF A THICK ALUMINUM PLATE, WHY MIGHT A LOWER

FREQUENCY (E.G., 2 MHZ) PROBE BE PREFERRED OVER A HIGHER FREQUENCY (5 MHZ) PROBE?**

A) LOWER FREQUENCY PROVIDES BETTER LATERAL RESOLUTION IN THE NEAR‑FIELD

B) LOWER FREQUENCY EXPERIENCES LESS ATTENUATION, ENABLING DEEPER PENETRATION

C) LOWER FREQUENCY REDUCES THE NEED FOR A WEDGE

D) LOWER FREQUENCY ELIMINATES GRATING LOBES AUTOMATICALLY

ANSWER: B

EXPLANATION: LOWER FREQUENCIES ATTENUATE LESS, ALLOWING THE BEAM TO REACH GREATER

DEPTHS IN HIGHLY ATTENUATIVE MATERIALS.

QUESTION 53. **WHEN USING A DUAL‑MODE (LONGITUDINAL/SHEAR) ARRAY, THE “SWITCH‑OVER

ANGLE” IS DEFINED AS:**

A) THE ANGLE AT WHICH THE INSTRUMENT AUTOMATICALLY CHANGES FROM LONGITUDINAL TO

SHEAR MODE

B) THE MAXIMUM STEERING ANGLE FOR SHEAR MODE BEFORE LOSS OF SENSITIVITY

C) THE ANGLE WHERE THE ACOUSTIC IMPEDANCE OF THE WEDGE MATCHES THAT OF THE TEST

MATERIAL

D) THE ANGLE BEYOND WHICH THE PROBE MUST BE ROTATED PHYSICALLY

ANSWER: A

EXPLANATION: THE SWITCH‑OVER ANGLE IS A PRESET STEERING ANGLE AT WHICH THE SYSTEM

CHANGES FROM LONGITUDINAL TO SHEAR WAVE EXCITATION TO MAINTAIN OPTIMAL SENSITIVITY.

ANSWER: B

EXPLANATION: CPD CURVES RELATE FLAW SIZE TO DETECTION PROBABILITY, HELPING ASSESS

INSPECTION RELIABILITY.

QUESTION 57. **WHEN A PAUT SCAN OF A PIPE SHOWS A “BRIGHT LINE” AT THE PIPE’S INNER

SURFACE, THIS IS MOST LIKELY DUE TO:**

A) A STRONG REFLECTOR FROM THE PIPE WALL (BACK‑WALL ECHO)

B) GRATING LOBE INTERFERENCE AT THAT DEPTH

C) EXCESSIVE ACG CAUSING OVER‑AMPLIFICATION

D) A CALIBRATION BLOCK BEING LEFT ON THE SURFACE

ANSWER: A

EXPLANATION: THE INNER SURFACE (BACK WALL) PROVIDES A STRONG, SPECULAR REFLECTION THAT

APPEARS AS A BRIGHT LINE IN THE IMAGE.

QUESTION 58. **THE PURPOSE OF “TIME‑GAIN COMPENSATION (TGC) SLIDERS” ON A PAUT

INSTRUMENT IS TO:**

A) MANUALLY ADJUST GAIN FOR SPECIFIC DEPTH RANGES DURING INSPECTION

B) SET THE STEERING ANGLE FOR EACH SCAN LINE

C) CONTROL THE PRF DYNAMICALLY AS THE PROBE MOVES

D) CHANGE THE WEDGE MATERIAL ON THE FLY

ANSWER: A

EXPLANATION: TGC SLIDERS ALLOW THE OPERATOR TO INCREASE OR DECREASE GAIN FOR DEFINED

DEPTH INTERVALS TO COMPENSATE FOR ATTENUATION.

QUESTION 59. IN PAUT, THE TERM “SYNTHETIC APERTURE” REFERS TO:

A) USING A PHYSICAL APERTURE LARGER THAN THE PROBE HOUSING

B) COMBINING DATA FROM MULTIPLE OVERLAPPING SCAN LINES TO EMULATE A LARGER APERTURE,

IMPROVING RESOLUTION

C) REPLACING THE WEDGE WITH A SYNTHETIC MATERIAL

D) OPERATING THE PROBE AT MULTIPLE FREQUENCIES SIMULTANEOUSLY

ANSWER: B

EXPLANATION: SYNTHETIC APERTURE PROCESSING MERGES ECHOES FROM OVERLAPPING BEAMS TO

CREATE THE EFFECT OF A LARGER APERTURE, ENHANCING IMAGE RESOLUTION.

QUESTION 60. **WHEN CALIBRATING A PAUT SYSTEM FOR A NEW WELD GEOMETRY, THE “GATE

PLACEMENT” MUST BE ADJUSTED TO ACCOUNT FOR:**

A) THE CURVATURE OF THE WELD ROOT

B) THE CHANGE IN PRF DUE TO WELD THICKNESS

C) THE DIFFERENCE IN ACOUSTIC IMPEDANCE BETWEEN FILLER AND BASE METAL

D) THE SCANNER’S ENCODER RESOLUTION

ANSWER: A

EXPLANATION: GATE POSITIONS MUST BE SET TO CAPTURE ECHOES FROM THE SPECIFIC GEOMETRY

(E.G., ROOT CURVATURE) TO ENSURE PROPER FLAW DETECTION.

QUESTION 61. **A PAUT INSTRUMENT IS SET TO A PRF OF 10 KHZ. IF THE MAXIMUM TRAVEL TIME FOR

AN ECHO FROM THE DEEPEST POINT IS 150 μS, THE SYSTEM IS OPERATING AT:** A) BELOW THE NYQUIST LIMIT, SAFE FROM ALIASING B) AT THE NYQUIST LIMIT, RISK OF ALIASING C) ABOVE THE NYQUIST LIMIT, ALIASING WILL OCCUR D) INDEPENDENT OF NYQUIST CONSIDERATIONS ANSWER: A EXPLANATION: NYQUIST REQUIRES PRF ≤ 1 / (2 × MAX TRAVEL TIME). HERE, 1/(2 × 150 μS) ≈ 3.33 KHZ; HOWEVER, THE PRF OF 10 KHZ EXCEEDS THIS, INDICATING ALIASING. THE CORRECT ANSWER IS C, BUT GIVEN THE OPTIONS, C IS APPROPRIATE. QUESTION 62. WHICH OF THE FOLLOWING IS A COMMON METHOD TO VERIFY THE “ENCODER CALIBRATION” OF AN AUTOMATED PAUT SCANNER? A) SCANNING A CALIBRATED GRID BLOCK AND MEASURING LINE SPACING IN THE RESULTING C‑SCAN B) ADJUSTING THE PRF UNTIL THE SCAN SPEED MATCHES THE ENCODER READING C) CHANGING THE WEDGE MATERIAL AND OBSERVING THE ECHO AMPLITUDE D) USING A HIGHER GAIN SETTING TO SEE IF THE ENCODER COUNTS INCREASE ANSWER: A

ASNT Phased Array Level II Ultimate Exam, Exams of Technology

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QUESTION 1. **WHICH WAVE MODE IS MOST SENSITIVE TO PLANAR CRACKS ORIENTED

PERPENDICULAR TO THE SURFACE IN AUSTENITIC STEEL?**

A) LONGITUDINAL WAVE

B) SHEAR WAVE

C) SURFACE WAVE

D) PLATE WAVE

ANSWER: B

EXPLANATION: SHEAR WAVES POLARIZE PARTICLE MOTION PARALLEL TO THE SURFACE, MAKING THEM

ESPECIALLY SENSITIVE TO CRACKS THAT OPEN IN THE SHEAR DIRECTION, SUCH AS PLANAR CRACKS

PERPENDICULAR TO THE INSPECTED SURFACE.

QUESTION 2. SNELL’S LAW FOR ULTRASONIC WAVES AT AN INTERFACE IS EXPRESSED AS:

A) SINΘ₁ / V₁ = SINΘ₂ / V₂

B) SINΘ₁ * V₁ = SINΘ₂ * V₂

C) SINΘ₁ / C₁ = SINΘ₂ / C₂

D) SINΘ₁ * C₁ = SINΘ₂ * C₂

ANSWER: A

EXPLANATION: SNELL’S LAW RELATES THE INCIDENT AND REFRACTED ANGLES TO THE VELOCITIES (OR

SOUND SPEEDS) OF THE TWO MEDIA: SINΘ₁ / V₁ = SINΘ₂ / V₂.

QUESTION 3. IN A PHASED‑ARRAY PROBE, THE “PITCH” REFERS TO:

A) THE DISTANCE BETWEEN THE FRONT FACE OF THE PROBE AND THE TEST PIECE

B) THE CENTER‑TO‑CENTER SPACING OF ADJACENT ACTIVE ELEMENTS

C) THE FREQUENCY BANDWIDTH OF THE PROBE

D) THE DELAY TIME APPLIED TO EACH ELEMENT FOR FOCUSING

ANSWER: B

EXPLANATION: PITCH IS THE CENTER‑TO‑CENTER SPACING OF ADJACENT TRANSDUCER ELEMENTS AND

DIRECTLY INFLUENCES GRATING‑LOBE FORMATION.

QUESTION 4. GRATING LOBES BECOME A CONCERN WHEN THE ELEMENT PITCH EXCEEDS:

A) 0.5 Λ IN THE TEST MATERIAL

B) Λ IN THE TEST MATERIAL

C) 1.5 Λ IN THE TEST MATERIAL

D) 2 Λ IN THE TEST MATERIAL

ANSWER: A

EXPLANATION: TO AVOID GRATING LOBES, THE PITCH SHOULD BE ≤ 0.5 Λ (WAVELENGTH IN THE TEST

MATERIAL) AT THE HIGHEST STEERING ANGLE.

QUESTION 5. THE PRIMARY PURPOSE OF A WEDGE IN PAUT IS TO:

A) INCREASE THE FREQUENCY OF THE TRANSMITTED WAVE

B) MATCH THE ACOUSTIC IMPEDANCE OF THE PROBE TO THE TEST MATERIAL

C) PROVIDE A CONTROLLED DELAY PATH FOR EACH ELEMENT

D) CONVERT SHEAR WAVES TO LONGITUDINAL WAVES ONLY

ANSWER: C

EXPLANATION: A WEDGE ADDS A KNOWN PATH LENGTH (DELAY) AND MAY ALSO CHANGE WAVE

MODE; ITS GEOMETRY DETERMINES THE TIME DELAY FOR EACH ELEMENT.

QUESTION 6. **WHICH OF THE FOLLOWING PROBE TYPES CONTAINS A TWO‑DIMENSIONAL MATRIX OF

ELEMENTS?**

A) LINEAR ARRAY

B) ANNULAR ARRAY

C) MATRIX ARRAY

D) DUAL‑MODE ARRAY

ANSWER: C

EXPLANATION: A MATRIX ARRAY HAS ROWS AND COLUMNS OF ELEMENTS, ENABLING ELECTRONIC

STEERING IN BOTH AZIMUTH AND ELEVATION.

QUESTION 7. WHEN PERFORMING A SECTORIAL (S‑SCAN) IN PAUT, THE BEAM IS:

A) STEERED THROUGH A RANGE OF ANGLES WHILE DEPTH IS FIXED

B) SCANNED LATERALLY ACROSS THE SPECIMEN SURFACE

ANSWER: B

EXPLANATION: THE IIW CONTAINS BOTH A LONGITUDINAL AND A SHEAR WIRE, ALLOWING

VERIFICATION OF VELOCITY AND GAIN SETTINGS FOR BOTH WAVE MODES.

QUESTION 11. **WHICH PARAMETER DIRECTLY INFLUENCES THE NEAR‑FIELD LENGTH (NF) OF A PAUT

PROBE?**

A) ELEMENT PITCH

B) FREQUENCY AND APERTURE SIZE

C) COUPLANT TEMPERATURE

D) PRF SETTING

ANSWER: B

EXPLANATION: NF ≈ D² / (4Λ), WHERE D IS APERTURE SIZE AND Λ IS WAVELENGTH; THUS FREQUENCY

(WHICH DETERMINES Λ) AND APERTURE SIZE ARE KEY.

QUESTION 12. THE “ACTIVE APERTURE” OF A PHASED ARRAY REFERS TO:

A) THE TOTAL PHYSICAL SIZE OF THE PROBE HOUSING

B) THE NUMBER OF ELEMENTS THAT ARE SIMULTANEOUSLY EXCITED FOR A GIVEN FOCAL LAW

C) THE DISTANCE BETWEEN THE PROBE AND THE TEST SURFACE

D) THE FREQUENCY BANDWIDTH OF THE PROBE

ANSWER: B

EXPLANATION: ACTIVE APERTURE IS THE SUBSET OF ELEMENTS THAT ARE ENERGIZED FOR A SPECIFIC

BEAM STEERING/FOCUSING OPERATION.

QUESTION 13. WHEN USING A DUAL‑MATRIX ARRAY (DMA), THE MAIN ADVANTAGE IS:

A) ABILITY TO GENERATE BOTH LONGITUDINAL AND SHEAR WAVES WITHOUT A WEDGE