100+ Free ASNT Level III IR Practice Questions
Pass your ASNT NDT Level III Infrared/Thermal Testing Method (IR) exam on the first try — instant access, no signup required.
A blackbody is at 500 K. If its temperature doubles to 1000 K, by approximately what factor does its total radiant emittance increase?
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Key Facts: ASNT Level III IR Exam
90
IR Method Questions
ASNT
2 hours
Time Limit
ASNT IR method
70%
Passing Score
ASNT typical cut score
8-14 um
LWIR Band
Microbolometer
3-5 um
MWIR Band
Cooled InSb/HgCdTe
Pearson VUE
Testing Partner
ASNT
ASNT's IR method exam is one of the five 90-question, 2-hour method exams in the Level III program. Candidates have 2 hours to answer 90 multiple-choice items covering heat transfer (Fourier, Newton, Stefan-Boltzmann, Planck, Wien), radiometry and emissivity, infrared imager design and performance (microbolometer LWIR vs cooled MWIR, NETD, IFOV), active thermography (pulsed, lock-in, vibrothermography, transient), passive applications (NETA electrical surveys, mechanical, building envelope, roof, refractory, steam trap), image analysis and reporting, and the standards that govern IR inspections. ASNT and Pearson VUE administer the exam at authorized test centers, with passing typically set near 70% of scored items.
Sample ASNT Level III IR Practice Questions
Try these sample questions to test your ASNT Level III IR exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1Fourier's law of heat conduction states that conductive heat flux is proportional to which of the following?
2Newton's law of cooling for convective heat transfer is expressed as:
3The Stefan-Boltzmann law for total radiant emittance of a blackbody is:
4A blackbody is at 500 K. If its temperature doubles to 1000 K, by approximately what factor does its total radiant emittance increase?
5Wien's displacement law relates the peak wavelength of blackbody emission to absolute temperature as:
6Using Wien's displacement law, the peak emission wavelength for a 300 K ambient surface is approximately:
7A surface at 800 K has peak emission near what wavelength?
8Planck's law describes:
9Which of the following is NOT a primary mode of heat transfer?
10Natural convection differs from forced convection primarily because:
About the ASNT Level III IR Exam
The ASNT NDT Level III Infrared/Thermal Testing (IR) method exam validates advanced knowledge of thermal NDT - including heat transfer theory, radiometry, infrared imagers, active and passive thermography, image interpretation, and the codes and standards that govern thermal inspection programs. This 100-question bank maps to the public ASNT CP-105 IR outline and standard reference materials (ASTM E1934, E1933, E1316, SNT-TC-1A, ASNT TIR) used for the 90-question, 2-hour Pearson VUE exam.
Assessment
90-question multiple-choice IR method exam (in addition to the 135-question Basic exam required for initial Level III certification)
Time Limit
2 hours
Passing Score
70%
Exam Fee
Tiered ASNT fee schedule depending on membership status (ASNT / Pearson VUE)
ASNT Level III IR Exam Content Outline
Heat Transfer Principles
Fourier conduction, Newton convection, Stefan-Boltzmann radiation (sigma T to the fourth), Planck spectral radiance, and Wien's displacement law applied to thermal NDT.
Radiometry & Emissivity
Blackbody emission, Kirchhoff's law of thermal radiation, emissivity of common engineering materials, reflected apparent temperature, and atmospheric transmission windows.
Infrared Imagers & Detectors
Uncooled microbolometer LWIR 8-14 um vs cooled InSb/HgCdTe MWIR 3-5 um, focal plane arrays, NETD, IFOV/MFOV spatial resolution, and integration time.
Active Thermography
Pulsed (flash) thermography, lock-in modulated thermography, vibrothermography (sonic/ultrasonic), and transient/step heating for subsurface defect detection.
Passive Thermography Applications
NETA electrical surveys, mechanical bearing/motor inspections, building-envelope air leakage, roof moisture mapping, refractory wall loss, and steam-trap diagnostics.
Image Analysis & Reporting
Span and level adjustment, palette selection, deltaT criteria for electrical findings, qualitative vs quantitative reporting, and required report content.
Standards & Qualification
ASTM E1316 terminology, E1934 electrical/mechanical IR guide, E1933 emissivity measurement, SNT-TC-1A, ASNT TIR reference, CP-105 IR topical outline, and ITC thermographer levels.
How to Pass the ASNT Level III IR Exam
What You Need to Know
- Passing score: 70%
- Assessment: 90-question multiple-choice IR method exam (in addition to the 135-question Basic exam required for initial Level III certification)
- Time limit: 2 hours
- Exam fee: Tiered ASNT fee schedule depending on membership status
Keys to Passing
- Complete 500+ practice questions
- Score 80%+ consistently before scheduling
- Focus on highest-weighted sections
- Use our AI tutor for tough concepts
ASNT Level III IR Study Tips from Top Performers
Frequently Asked Questions
How long is the ASNT Level III IR method exam?
It is a 90-question multiple-choice exam with a 2-hour time limit, the same structure ASNT uses for IR, MFL, MT, PT, and VT method exams. Candidates must also pass the 135-question, 4-hour Basic exam for initial Level III certification.
What passing score do I need?
Plan for roughly 70% of scored items. ASNT publishes that Level III cut scores fall in the 70%-80% range and are set with accepted psychometric methods, but it does not publish an exact percentage by method.
What spectral bands does the IR exam emphasize?
Two atmospheric windows dominate the exam: long-wave infrared 8-14 micrometers, used by uncooled microbolometer cameras, and mid-wave infrared 3-5 micrometers, used by cooled photon detectors such as InSb and HgCdTe. The exam expects you to know which band fits each application.
Which standards are referenced most often?
ASTM E1316 (NDT terminology), ASTM E1934 (electrical and mechanical equipment IR), ASTM E1933 (emissivity measurement), SNT-TC-1A and CP-189 for personnel qualification, ASNT CP-105 for the IR topical outline, and the ASNT TIR reference book. NETA's MTS deltaT priorities are also commonly tested for electrical surveys.
What is the difference between active and passive thermography?
Passive thermography measures the existing thermal signature of equipment under normal operating conditions, while active thermography applies external thermal stimulation - flash, modulated lamp, mechanical vibration, or step heating - and observes the surface response over time to characterize subsurface features.
How is emissivity handled on the exam?
You should know that emissivity is the ratio of actual emitted radiance to that of a blackbody at the same temperature, that Kirchhoff's law states absorptivity equals emissivity at thermal equilibrium, and that incorrect emissivity is one of the largest sources of error in radiometric temperature measurement. ASTM E1933 documents two practical emissivity measurement methods.
Does this bank cover both Basic and IR-method content?
This 100-question bank focuses on the IR method exam outline. Candidates pursuing initial Level III certification should also use the separate Basic-exam bank to prepare for the 135-question, 4-hour Basic exam every Level III candidate must pass.