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ASNT NDT Level III PT study materials
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ASNT NDT Level III PT practice questions

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Question 1Penetrant Testing Method Fundamentals and Principles

The physical mechanism by which a liquid penetrant enters a surface-breaking discontinuity is best described as:

  1. Electrostatic repulsion pushing liquid inward
  2. Magnetic attraction between penetrant and metal
  3. Capillary action drawing liquid into a narrow opening Correct answer.
  4. Gravitational settling of dense liquid into the void

Explanation

Penetrant enters discontinuities primarily by capillary action, which is driven by surface tension and wetting forces in narrow openings. Gravity plays only a minor secondary role and magnetic or electrostatic forces are not the operative mechanism.

Question 2Penetrant Testing Method Fundamentals and Principles

A penetrant that contains a visible dye and is used without a developer, evaluated under white light, is classified as:

  1. Visible dye penetrant Correct answer.
  2. Dual-mode penetrant
  3. Post-emulsifiable penetrant
  4. Fluorescent penetrant

Explanation

Visible dye penetrants rely on a strongly colored dye observed under white light. Fluorescent penetrants require ultraviolet light and a developer, and post-emulsifiable is a removal classification, not a visibility classification.

Question 3Penetrant Testing Method Fundamentals and Principles

The primary function of a developer in penetrant testing is to:

  1. Neutralize residual penetrant in the defect
  2. Draw penetrant out of discontinuities to form a visible indication Correct answer.
  3. Increase the capillary entry of penetrant into defects
  4. Dissolve the excess surface penetrant

Explanation

Developer provides a contrasting background and acts as a blotting medium that draws trapped penetrant out of discontinuities so it spreads and becomes visible. It is applied after penetrant dwell and removal, so it does not assist entry.

Question 4Penetrant Testing Method Fundamentals and Principles

Which property of a penetrant most directly controls its ability to wet and enter fine surface openings?

  1. Surface tension Correct answer.
  2. Viscosity
  3. Specific gravity
  4. Flash point

Explanation

Low surface tension promotes wetting and capillary penetration into narrow discontinuities. Viscosity affects drain time and flow but wetting is governed primarily by surface tension.

Question 5Penetrant Testing Method Fundamentals and Principles

The dwell time for a penetrant is the period during which the penetrant is:

  1. Drying on the surface before development
  2. Being washed from the surface
  3. Left on the part to enter discontinuities Correct answer.
  4. Being emulsified before removal

Explanation

Dwell time is the interval the penetrant is allowed to remain on the part so capillary action can fill discontinuities. Removal, emulsification, and drying occur after the dwell period.

Question 6Penetrant Testing Method Fundamentals and Principles

Which penetrant removal method uses a separate emulsifier applied after the penetrant dwell?

  1. Post-emulsifiable removal Correct answer.
  2. Water-washable removal
  3. Lipophilic removal
  4. Solvent removal

Explanation

In the post-emulsifiable method, an emulsifier is applied after penetrant dwell to make the surface penetrant water-rinsable. Lipophilic is a type of emulsifier, not a removal method category.

Question 7Penetrant Testing Method Fundamentals and Principles

A lipophilic emulsifier works by:

  1. Chemically reacting with the dye to bleach it
  2. Dissolving the developer residue
  3. Dispersing water into the penetrant film
  4. Combining with the surface penetrant so it can be rinsed away Correct answer.

Explanation

Lipophilic (oil-based) emulsifiers combine with the oily penetrant on the surface, forming a mixture that water can rinse away. The emulsifier must not be allowed to over-emulsify into discontinuities.

Question 8Penetrant Testing Method Fundamentals and Principles

Which condition would most likely cause excessive background fluorescence or color from residual penetrant after washing?

  1. Proper emulsifier dwell
  2. Use of a dry developer
  3. Insufficient penetrant dwell
  4. Insufficient rinse time or pressure Correct answer.

Explanation

Inadequate rinsing leaves penetrant on the surface, producing high background that can mask true indications. Insufficient dwell would reduce indications rather than create background.

Question 9Penetrant Testing Method Fundamentals and Principles

The purpose of applying a thin, uniform developer coating is to:

  1. Seal the surface so penetrant cannot escape
  2. Increase penetrant entry before removal
  3. Provide a uniform contrasting background and controlled blotting Correct answer.
  4. Prevent the part from corroding during inspection

Explanation

A thin, uniform developer layer provides a contrasting background and controlled extraction of penetrant so indications are distinct. Excessive developer can mask small indications and is avoided.

Question 10Penetrant Testing Method Fundamentals and Principles

Which developer form is typically supplied as a fine powder that is dusted or floated onto the part?

  1. Non-aqueous developer
  2. Water-soluble developer
  3. Dry powder developer Correct answer.
  4. Water-suspendible developer

Explanation

Dry powder developer is applied by dusting or in a dust storm chamber and is commonly used with fluorescent penetrants. Water-soluble and water-suspendible developers are applied as liquid coatings that dry on the part.

Question 11Penetrant Testing Method Fundamentals and Principles

A water-soluble developer differs from a water-suspendible developer in that the water-soluble type:

  1. Dissolves completely in water to form a solution Correct answer.
  2. Contains suspended insoluble particles
  3. Requires no drying after application
  4. Is used only with visible dye penetrants

Explanation

Water-soluble developers form a true solution in water, while water-suspendible developers contain insoluble particles held in suspension. Both are applied as coatings that dry on the part.

Question 12Penetrant Testing Method Fundamentals and Principles

Which penetrant system generally offers the highest sensitivity for detecting very fine discontinuities?

  1. Visible dye water-washable penetrant
  2. Solvent-removable visible dye penetrant
  3. Fluorescent post-emulsifiable penetrant Correct answer.
  4. Visible dye post-emulsifiable penetrant

Explanation

Fluorescent penetrants combined with post-emulsification provide high sensitivity because fluorescence improves contrast and post-emulsification allows controlled removal. Visible dye systems generally have lower sensitivity than fluorescent systems.

Question 13Penetrant Testing Method Fundamentals and Principles

The term 'flash point' of a penetrant material refers to:

  1. The temperature at which the liquid begins to freeze
  2. The temperature at which the dye degrades
  3. The maximum temperature the part may reach during inspection
  4. The lowest temperature at which vapors ignite when exposed to an ignition source Correct answer.

Explanation

Flash point is the lowest temperature at which a liquid gives off sufficient vapor to ignite when exposed to an ignition source. It is a safety property that governs storage and use conditions.

Question 14Penetrant Testing Method Fundamentals and Principles

A penetrant indication appears as a broad, diffuse area rather than a sharp line. This is most characteristic of:

  1. A forging lap
  2. A through-thickness weld crack
  3. A tight crack
  4. A porosity cluster or surface roughness Correct answer.

Explanation

Broad diffuse indications often result from clustered porosity or surface roughness where penetrant bleeds from many small openings. Linear, sharp indications are more typical of cracks and laps.

Question 15Penetrant Testing Method Fundamentals and Principles

When using a solvent-removable penetrant, the correct sequence is:

  1. Apply penetrant, dwell, remove with solvent, apply developer, inspect Correct answer.
  2. Apply penetrant, apply developer, dwell, remove, inspect
  3. Apply penetrant, dwell, apply developer, remove with solvent, inspect
  4. Apply developer, apply penetrant, dwell, remove, inspect

Explanation

Penetrant is applied and allowed to dwell, excess is removed with solvent, developer is applied, and the part is inspected. Removal must precede developer application so indications are not masked.

Question 16Penetrant Testing Method Fundamentals and Principles

The primary reason for pre-cleaning a part before penetrant testing is to:

  1. Reduce the required dwell time to zero
  2. Make the developer unnecessary
  3. Increase the flash point of the penetrant
  4. Remove contaminants that could block penetrant entry Correct answer.

Explanation

Contaminants such as oil, scale, paint, or moisture can block discontinuities and prevent penetrant entry, causing missed indications. Pre-cleaning ensures open, penetrable surfaces.

Question 17Penetrant Testing Method Fundamentals and Principles

Which of the following is a common cause of false indications in penetrant testing?

  1. Adequate rinse pressure
  2. Penetrant trapped in surface roughness or threads Correct answer.
  3. Incomplete drying before developer application
  4. Use of a developer film

Explanation

Penetrant retained in surface roughness, threads, keyways, or similar features can bleed out and mimic true indications. These are false indications from geometry rather than actual discontinuities.

Question 18Penetrant Testing Method Fundamentals and Principles

Which approach is generally recommended when inspecting a part with a rough, porous surface?

  1. Use a high-sensitivity fluorescent system without removal
  2. Skip the developer step
  3. Select a lower-sensitivity penetrant and control removal carefully Correct answer.
  4. Increase penetrant dwell and developer thickness

Explanation

Rough surfaces retain penetrant and create background, so a lower-sensitivity system with careful removal helps distinguish true indications. Increasing dwell or developer thickness would worsen background.

Question 19Penetrant Testing Method Fundamentals and Principles

The function of a hydrophilic emulsifier in the post-emulsification process is to:

  1. Neutralize the dye so it cannot fluoresce
  2. React with developer to increase contrast
  3. Make the surface penetrant water-rinsable by forming a water-based film Correct answer.
  4. Soak into discontinuities and displace penetrant

Explanation

Hydrophilic (water-based) emulsifiers wet the surface penetrant and make it removable by water rinse. Their concentration and contact time are controlled to prevent over-emulsification of penetrant in discontinuities.

Question 20Penetrant Testing Method Fundamentals and Principles

A part is inspected with fluorescent penetrant under ultraviolet light. A bright indication is observed but disappears when the part is wiped. This most likely represents:

  1. A subsurface defect
  2. A true crack indication
  3. A developer defect
  4. A false indication from surface penetrant Correct answer.

Explanation

Indications that disappear when wiped are typically surface penetrant residue rather than penetrant bled from a discontinuity. True indications tend to persist or reappear because penetrant remains trapped in the defect.

Question 21Penetrant Testing Method Fundamentals and Principles

Which factor most strongly influences the choice of penetrant dwell time?

  1. Size of the inspection area
  2. Type of discontinuity and surface finish Correct answer.
  3. Ambient humidity only
  4. Color of the part

Explanation

Dwell time is selected based on the expected discontinuity type (tight cracks need longer dwell) and surface condition, along with penetrant type and temperature. Part color and inspection area do not govern dwell.

Question 22Penetrant Testing Method Fundamentals and Principles

A penetrant that is removed by water spray without a separate emulsifier step is called:

  1. Lipophilic penetrant
  2. Water-washable penetrant Correct answer.
  3. Solvent-removable penetrant
  4. Post-emulsifiable penetrant

Explanation

Water-washable penetrants contain built-in emulsifiers and are removed directly with water. Post-emulsifiable penetrants require a separate emulsifier, and solvent-removable penetrants use solvent wipes.

Question 23Penetrant Testing Method Fundamentals and Principles

Which statement about the effect of temperature on penetrant testing is most accurate?

  1. High temperature always improves sensitivity without risk
  2. Temperature has negligible effect on penetrant behavior
  3. Low temperature increases penetrant viscosity and slows penetration Correct answer.
  4. Temperature affects only the developer

Explanation

Low temperatures raise penetrant viscosity and reduce capillary penetration, requiring longer dwell or warming. High temperatures can cause penetrant to dry out or evaporate, reducing sensitivity and creating safety concerns.

Question 24Penetrant Testing Method Fundamentals and Principles

The main reason for controlling emulsifier contact time is to:

  1. Prevent over-emulsification that removes penetrant from discontinuities Correct answer.
  2. Increase the dye concentration in the penetrant
  3. Reduce the required developer dwell
  4. Improve the flash point of the penetrant

Explanation

Excessive emulsifier contact time allows the emulsifier to enter discontinuities and make trapped penetrant water-rinsable, which can wash out true indications. Contact time is therefore closely controlled.

Question 25Penetrant Testing Method Fundamentals and Principles

A linear indication on a weld toe that is sharp and continuous is most likely to be:

  1. Surface roughness
  2. A forging lap
  3. A cluster of porosity
  4. A crack or toe defect Correct answer.

Explanation

Sharp, continuous linear indications at a weld toe are characteristic of cracks or toe defects. Porosity tends to be rounded or clustered, and roughness produces diffuse background.

Question 26Penetrant Testing Method Fundamentals and Principles

Which statement best describes the principle by which liquid penetrant testing detects surface discontinuities?

  1. Penetrant is forced into discontinuities by applying pressure during the dwell period.
  2. Penetrant fills discontinuities and is drawn out by gravity when the part is inverted.
  3. Capillary action draws penetrant into surface openings, and developer draws it back out. Correct answer.
  4. Penetrant reacts chemically with the material inside a discontinuity to form a visible compound.

Explanation

Penetrant testing relies on capillary action to draw the liquid into surface-breaking discontinuities. After excess penetrant is removed, developer is applied; it acts as a blotter and draws penetrant back out through capillary action, forming an indication.

Question 27Penetrant Testing Method Fundamentals and Principles

What is the primary function of a developer in penetrant testing?

  1. To chemically neutralize the penetrant after inspection.
  2. To draw penetrant from discontinuities and provide a contrasting background. Correct answer.
  3. To increase the capillary action that pulls penetrant into discontinuities.
  4. To remove excess surface penetrant from the part.

Explanation

Developer serves as a blotter that draws trapped penetrant out of discontinuities and forms a uniform background that enhances the visibility of indications. It does not remove penetrant or neutralize it chemically.

Question 28Penetrant Testing Method Fundamentals and Principles

Which of the following is a characteristic of a solvent-removable penetrant system?

  1. It is removed with a water spray without any emulsifier.
  2. It is removed only by immersion in an ultrasonic solvent bath.
  3. It is removed by wiping with a solvent-moistened cloth, followed by a clean dry wipe. Correct answer.
  4. It requires a separate emulsifier step after penetrant dwell.

Explanation

Solvent-removable penetrants are removed by wiping with a solvent-moistened cloth, then a dry wipe, without a water wash or emulsifier. This makes the method portable and suitable for localized inspections.

Question 29Penetrant Testing Method Fundamentals and Principles

A penetrant is described as 'water-washable.' How is excess penetrant removed from the part?

  1. By washing with water spray without a separate emulsifier step. Correct answer.
  2. By wiping with solvent and then drying.
  3. By dusting with developer and brushing off the excess.
  4. By applying a lipophilic emulsifier before washing.

Explanation

Water-washable penetrants contain surfactants that make them removable directly with a water spray, without a separate emulsifier. The wash step must be controlled to avoid over-washing fine indications.

Question 30Penetrant Testing Method Fundamentals and Principles

What is the purpose of the penetrant dwell time?

  1. To allow the developer to dry before inspection.
  2. To allow the penetrant to cure and harden on the surface.
  3. To allow capillary action to draw penetrant into discontinuities. Correct answer.
  4. To allow the emulsifier to react with the penetrant.

Explanation

Dwell time is the period after penetrant application during which capillary action draws the liquid into surface discontinuities. It must be long enough to ensure adequate penetration, especially for tight or shallow defects.

Question 31Penetrant Testing Method Fundamentals and Principles

How does the viscosity of a penetrant affect its performance?

  1. Viscosity has no effect on penetration into discontinuities.
  2. Lower viscosity generally allows faster penetration into fine discontinuities. Correct answer.
  3. Higher viscosity increases penetration speed into fine discontinuities.
  4. Higher viscosity improves the contrast of indications.

Explanation

Lower-viscosity penetrants flow more readily and penetrate fine discontinuities faster, although very low viscosity may increase drainage and background. Viscosity affects penetration speed but not the contrast of the indication.

Question 32Penetrant Testing Method Fundamentals and Principles

A part is inspected with a fluorescent penetrant, and a bright indication appears under ultraviolet light. After a few minutes, the indication fades and disappears. What is the most likely explanation?

  1. The penetrant has fully drained from the discontinuity. Correct answer.
  2. The penetrant is over-washed from the discontinuity.
  3. The ultraviolet light source is fluctuating.
  4. The developer coating is too thin.

Explanation

A fading indication often indicates that the penetrant is draining out of a shallow or open discontinuity, or that the discontinuity is not tightly closed. This is common with surface-connected defects that do not retain penetrant.

Question 33Penetrant Testing Method Fundamentals and Principles

Which property of a liquid penetrant describes its ability to spread over and wet the surface of a test part?

  1. Volatility
  2. Specific gravity
  3. Wettability Correct answer.
  4. Flash point

Explanation

Wettability is the tendency of a liquid to spread over and cling to a solid surface, which is what allows penetrant to enter and remain in tight surface openings. It is governed largely by surface tension and contact angle. The other listed properties concern evaporation, fire hazard, or density rather than surface wetting.

Question 34Penetrant Testing Method Fundamentals and Principles

A technician must test a part for discontinuities that are open only to the bottom surface, which is fully accessible, while keeping the top surface clean. Which penetrant application approach best satisfies this requirement?

  1. Immerse the whole part in a penetrant bath, then drain and wash the top surface
  2. Apply penetrant only to the accessible bottom surface and allow capillary action to draw it into the openings Correct answer.
  3. Spray the entire part from above and rely on gravity to carry penetrant through the part
  4. Apply penetrant to the top surface and let it seep through the material to the bottom openings

Explanation

Penetrant testing detects only discontinuities that are open to the surface being treated, and the liquid enters by capillary action from that surface. Applying penetrant to the accessible surface that contains the openings allows it to be drawn in without contaminating the opposite face. Penetrant does not migrate through sound material to reach openings on a different face.

Question 35Penetrant Testing Equipment, Materials, and Techniques

A penetrant that contains no visible dye and is evaluated under ultraviolet light is classified as which type?

  1. Type I fluorescent Correct answer.
  2. Type IV solvent-removable
  3. Type III dual-purpose
  4. Type II visible

Explanation

Penetrant types are grouped by dye content: fluorescent penetrants (Type I) fluoresce under UV-A, while visible penetrants (Type II) rely on a contrasting dye under white light. The removal method is a separate classification (Methods A through D), not part of the type designation.

Question 36Penetrant Testing Equipment, Materials, and Techniques

Which developer form is supplied as a fine powder that is suspended in a volatile liquid carrier and dries to a thin, uniform coating?

  1. Non-aqueous developer Correct answer.
  2. Dry powder developer
  3. Water-soluble developer
  4. Water-suspendible developer

Explanation

Non-aqueous developers (Form d) disperse developer powder in a volatile solvent carrier that evaporates, leaving a thin, even layer that enhances bleedout contrast. Water-soluble and water-suspendible developers use water-based carriers that require careful drying.

Question 37Penetrant Testing Equipment, Materials, and Techniques

The primary purpose of a penetrant remover/cleaner is to do which of the following?

  1. Neutralize the penetrant chemically before development
  2. Remove surface penetrant without drawing penetrant from discontinuities Correct answer.
  3. Increase the fluorescence of retained penetrant
  4. Seal discontinuities so penetrant cannot escape

Explanation

Removal must strip excess surface penetrant while leaving penetrant trapped in discontinuities intact. Over-removal washes out indications, while under-removal leaves a background that masks indications. Removers are not designed to alter or neutralize the retained penetrant.

Question 38Penetrant Testing Equipment, Materials, and Techniques

Which penetrant removal method is generally specified for use with a solvent-removable (Method C) process?

  1. Electrolytic cleaning in a salt solution
  2. Wiping with clean, dry cloths followed by a solvent-dampened cloth Correct answer.
  3. Immersion in an emulsifier bath
  4. Direct high-pressure water spray

Explanation

Solvent removal uses clean absorbent wipes, often with a light solvent wipe, to lift surface penetrant without flushing flaws. High-pressure water and emulsifiers belong to other removal methods. Electrolytic cleaning is a pre-cleaning operation, not a penetrant removal step.

Question 39Penetrant Testing Equipment, Materials, and Techniques

A hydrophilic emulsifier used in the post-emulsifiable process is best described as which of the following?

  1. A lipophilic oil-based emulsifier
  2. A volatile solvent applied with a wipe
  3. A water-based emulsifier applied by immersion or spray Correct answer.
  4. A dry powder applied in a dust storm

Explanation

Hydrophilic emulsifiers are water-based and are applied after the penetrant dwell to make the excess surface penetrant water-rinsable. Lipophilic emulsifiers are oil-based and act by a different mechanism. Dry powder and volatile solvents are developer and remover materials, respectively.

Question 40Penetrant Testing Equipment, Materials, and Techniques

Which material is commonly used as a carrier for fluorescent penetrants because of its high solvency and low volatility?

  1. Aqueous ammonia
  2. Distilled water
  3. Liquid carbon dioxide
  4. A high-boiling petroleum distillate Correct answer.

Explanation

Penetrant carriers are typically high-boiling organic liquids that dissolve the dye, wet surfaces well, and resist premature evaporation during dwell. Water and highly volatile or reactive liquids are unsuitable carriers for this purpose.

Question 41Penetrant Testing Equipment, Materials, and Techniques

When using a black light for fluorescent penetrant inspection, the examination area should be shielded from which of the following?

  1. Ultraviolet radiation from the lamp
  2. Airborne dust particles
  3. Ambient humidity
  4. Visible white light that could mask indications Correct answer.

Explanation

Visible white light raises the background and reduces the contrast of fluorescent indications, so the inspection area is darkened and shielded from white light. The black light itself is the required UV source, not something to be shielded.

Question 42Penetrant Testing Equipment, Materials, and Techniques

Penetrant materials that will be used on nickel-base alloys in a nuclear application should be checked for which of the following?

  1. Total halogen and sulfur content Correct answer.
  2. Color under white light
  3. Viscosity at room temperature
  4. Specific gravity above 1.0

Explanation

Halogens and sulfur can cause stress-corrosion cracking in austenitic and nickel-base alloys, so penetrant materials are controlled for these contaminants, often per a qualified product list. Specific gravity, color, and viscosity are not the controlling contamination concern.

Question 43Penetrant Testing Equipment, Materials, and Techniques

A water-washable penetrant is being used, and the technician must rinse the part after dwell. Which rinse condition is most appropriate?

  1. A steam jet directed at the part
  2. A fine, low-pressure spray with the part kept at a distance Correct answer.
  3. A coarse, high-pressure spray held close to the surface
  4. Immersion in a still water bath for several minutes

Explanation

Water-washable penetrants are removed with a fine, low-pressure rinse applied from a distance to avoid over-washing penetrant from discontinuities. High-pressure or close spray and prolonged immersion tend to flush flaws and reduce sensitivity.

Question 44Penetrant Testing Equipment, Materials, and Techniques

A technician is using a post-emulsifiable penetrant and must decide when to apply the emulsifier. The correct sequence is to apply the emulsifier after which step?

  1. After the water rinse and before drying
  2. After final inspection and before cleaning
  3. After the penetrant dwell and before the water rinse Correct answer.
  4. After the developer has been applied

Explanation

In post-emulsifiable processing, the emulsifier is applied after the penetrant dwell time and before the water rinse so that excess surface penetrant becomes water-rinsable. Applying it after development or after rinsing would not serve its purpose.

Question 45Penetrant Testing Equipment, Materials, and Techniques

During a fluorescent penetrant inspection, a technician observes a bright indication that appears only when the part is viewed under UV light. This observation indicates which of the following?

  1. A visible dye indication
  2. A fluorescent indication Correct answer.
  3. A developer defect
  4. A rinse-water residue

Explanation

Fluorescent indications appear bright under UV-A because retained fluorescent penetrant emits visible light. Visible dye indications are seen under white light, and developer or rinse residues would not produce the characteristic fluorescence.

Question 46Penetrant Testing Equipment, Materials, and Techniques

A dry powder developer is being applied to a part. Which application technique is appropriate for this developer form?

  1. Brushing the powder onto the surface
  2. Immersion in a developer slurry
  3. Dusting in a closed chamber or with a powder blower Correct answer.
  4. Spraying from an aerosol can

Explanation

Dry powder developer is applied as a cloud of fine powder, typically in a dust chamber or with a powder blower, so a light uniform layer settles on the surface. Slurries and aerosols apply other developer forms, and brushing gives an uneven coating.

Question 47Penetrant Testing Equipment, Materials, and Techniques

A technician is selecting a penetrant for inspecting a rough, cast surface where a thin, uniform film is difficult to achieve. Which penetrant property is most important to consider?

  1. Low viscosity for good coverage of rough surfaces Correct answer.
  2. High water content
  3. Strong visible color under UV light
  4. High viscosity for better cling

Explanation

Lower-viscosity penetrants flow into surface irregularities and drain more evenly, which helps on rough surfaces. High viscosity tends to pool and leave heavy background, and water content is not a desirable penetrant property.

Question 48Penetrant Testing Equipment, Materials, and Techniques

A part is being processed with a solvent-removable penetrant. After the dwell, the technician wipes the surface with a solvent-dampened cloth. Why is a dry wipe usually performed before the solvent wipe?

  1. To increase the penetrant dwell time
  2. To cool the part before development
  3. To remove most surface penetrant before solvent is applied Correct answer.
  4. To activate the fluorescent dye

Explanation

A dry wipe first lifts the bulk of surface penetrant, so the solvent wipe is used sparingly and does not flush penetrant from discontinuities. Applying solvent first can spread penetrant and over-remove from flaws.

Question 49Penetrant Testing Equipment, Materials, and Techniques

A water-suspendible developer is being prepared. Which of the following is the most important control for consistent results?

  1. Maintaining the specified concentration and agitation of the suspension Correct answer.
  2. Keeping the bath at boiling temperature
  3. Adding solvent to thin the mixture
  4. Allowing the powder to settle completely before use

Explanation

Water-suspendible developer must be kept at the specified concentration with continuous or frequent agitation so the suspended powder stays uniform. Settling produces inconsistent coating thickness, and solvent addition or boiling is not appropriate.

Question 50Penetrant Testing Equipment, Materials, and Techniques

A technician is evaluating whether a black light is adequate for inspection. Which parameter should be verified?

  1. The color temperature of the lamp housing
  2. The wattage rating of the bulb only
  3. The UV-A irradiance at the inspection surface Correct answer.
  4. The length of the power cord

Explanation

Adequacy of a black light is judged by the UV-A irradiance measured at the inspection surface, not by bulb wattage alone. Irradiance is checked with a suitable UV-A meter before inspection.