ASNT Visual Testing - Level III Practice Questions — 10 Free (2026)

During procedure review, a Level III finds that a radiographer believes an image quality indicator is used to judge the acceptability of discontinuities. The Level III corrects this: the IQI actually demonstrates:

• A. the total exposure time used for the shot
• B. that the required level of radiographic sensitivity has been achieved ✓
• C. the geometric unsharpness of the exposure arrangement
• D. that film density falls inside the range permitted by the governing code for the exposed radiograph
• E. the size of the smallest rejectable flaw

An IQI is a gage of overall radiographic quality: if its required feature is visible, the technique has demonstrated adequate sensitivity. It is not a measure of flaw acceptability, density, or exposure time. ASNT Level III Study Guide Basic, Section 2 - Radiographic Testing

Internal surfaces of small-bore tubing must be examined visually without sectioning the tubes. The most appropriate aid is:

• A. a low power magnifying glass
• B. a portable ultraviolet lamp positioned at each open tube end
• C. a borescope or fiberscope inserted into the bore ✓
• D. a mirror on an extension handle only
• E. a stereo microscope on a bench stand

Borescopes and fiberscopes carry both illumination and the image path into confined bores, making remote visual examination possible without destructive sectioning. Magnifiers, microscopes, and simple mirrors cannot reach deep inside small-bore tubing. ASNT Level III Study Guide Basic, Section 2 - Visual Testing

A contract reviewer asks the NDT Level III to characterize the basic nature of SNT-TC-1A for use in a supplier quality plan. Which description is accurate?

• A. It is a third-party certification scheme under which ASNT itself certifies every Level I and Level II working in industry.
• B. It is a set of guidelines the employer applies with flexibility and judgment when building a written practice. ✓
• C. It is an ANSI consensus standard with mandatory minimums.
• D. It is a strict specification whose wording cannot be modified.
• E. It is a legally binding federal regulation for NDT personnel.

SNT-TC-1A is a recommended practice: it offers recommendations that each employer tailors through its own written practice, unlike a mandatory standard or a regulation. ASNT Level III Study Guide Basic, Section 1 - SNT-TC-1A

While developing an immersion technique, a Level III must determine the wavelength of a 5 MHz longitudinal wave in steel, where the longitudinal velocity is 5900 m per second. The wavelength is:

• A. 0.30 mm
• B. 0.59 mm
• C. 1.18 mm ✓
• D. 2.36 mm
• E. 4.72 mm

Wavelength equals velocity divided by frequency, and the result sets the practical lower limit of detectable reflector size. At 5 MHz in steel this works out to slightly more than one millimeter. ASNT Level III Study Guide Basic, Section 2 - Ultrasonic Testing

Which application is outside the capability of conventional eddy current testing?

• A. measuring the thickness of nonconductive paint applied over an aluminum skin
• B. sorting mixed alloys by conductivity
• C. detecting surface cracks in heat exchanger tubing
• D. detecting internal shrinkage deep inside a thick steel casting ✓
• E. verifying heat treatment condition of aluminum parts

Eddy currents are confined to the surface and near-surface region of conductive materials, so deep internal flaws in thick sections are beyond the method. Conductivity sorting, coating thickness measurement, tubing inspection, and heat treat verification are all classic ET uses. ASNT Level III Study Guide Basic, Section 2 - Electromagnetic Testing

Ranked by photon energy, the most energetic radiation routinely encountered in an NDT facility is:

• A. white light reflected at the examination surface
• B. gamma photons from a cobalt-60 source ✓
• C. infrared emission mapped by a thermal imager
• D. visible green light from a fluorescent indication
• E. UV-A from an inspection lamp

Photon energy rises as wavelength shortens, and cobalt-60 emissions sit at the extreme short wavelength end of anything used in the shop, far above ultraviolet, visible and infrared light. That is also why only the radiographic sources are ionizing. ASNT Level III Study Guide Basic, Section 2 - Radiographic Testing 1.1.3

Four candidates are proposed for employer certification as NDT Level III. Per the education and experience recommendations of SNT-TC-1A Section 6, which candidate satisfies a recommended route without relying on the employer's discretion to modify the guidelines?

• A. A candidate with two years of university engineering study plus one additional year of comparable NDT experience.
• B. An engineering graduate of a four-year college with one additional year of experience comparable to Level II work in the applicable method. ✓
• C. A science graduate of a four-year program with no NDT experience at all, accepted on the condition that the Basic examination is passed on the first attempt.
• D. A candidate with three years of experience beyond the Level II requirements.
• E. A high school graduate with one year of Level II comparable experience.

The recommended routes are a four-year engineering or science degree plus one additional year of Level II comparable experience, two years of such study plus two additional years, or four years of experience beyond the Level II requirements. Two years of study with only one added year, or three years of experience alone, fall short. ASNT Level III Study Guide Basic, Chapter 2 - Recommended Practice No. SNT-TC-1A

Individual measurements from a stable process follow an approximately normal distribution. About what portion of the values is expected to fall within plus or minus two standard deviations of the mean?

• A. 33 percent
• B. 50 percent
• C. 68 percent
• D. 95 percent ✓
• E. 99.7 percent

For a normal distribution roughly two thirds of values lie within one standard deviation, about nineteen in twenty within two, and nearly all within three. ASNT Level III Study Guide Basic, Chapter 17 - Inspection

When a Level III drafts the radiation protection section of an internal NDT safety manual, the three fundamental exposure controls that should anchor the text are:

• A. training, signage and fencing
• B. surveys, badges and alarms
• C. time, distance and shielding ✓
• D. collimation, filtration and masking
• E. dosimetry, licensing and audits

Every practical protection measure reduces to minimizing exposure duration, maximizing separation from the source, or interposing attenuating material. The other groupings are administrative or hardware details that support, but do not replace, these three controls. ASNT Level III Study Guide Basic, Section 2 - Radiographic Testing 1.1.4

A specification requires finding and quantifying an extremely small leak in a sealed stainless steel vessel. Which leak testing technique offers the greatest sensitivity?

• A. helium mass spectrometer testing ✓
• B. bubble immersion testing
• C. ultrasonic listening for escaping gas
• D. ammonia sensitized paper testing
• E. pressure change (pressure decay) measurement over time

Mass spectrometer techniques using helium tracer gas detect far smaller leakage rates than bubble, pressure change, chemical, or sonic techniques. They also provide a quantitative leak rate rather than a simple indication. ASNT Level III Study Guide Basic, Section 2 - Leak Testing