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Inspection & Testing (ET105) study materials
Inspection & Testing (ET105) study resources

Inspection & Testing (ET105) practice questions

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Question 1Inspection Fundamentals and Terminology

In inspection terminology, a deviation from a specified requirement that could affect the item's function or safety is best described as a:

  1. allowance
  2. defect Correct answer.
  3. datum
  4. tolerance

Explanation

A defect is a nonconformance serious enough to affect function, safety, or fitness for use. Tolerance and allowance are design quantities, while a datum is a reference.

Question 2Inspection Fundamentals and Terminology

Which document typically states the acceptance criteria an inspector uses to judge a lot of incoming parts?

  1. the inspection plan Correct answer.
  2. the maintenance log
  3. the purchase requisition
  4. the shift schedule

Explanation

An inspection plan defines what characteristics to check, the method, sample size, and acceptance criteria. Requisitions, logs, and schedules do not carry acceptance criteria.

Question 3Inspection Fundamentals and Terminology

A measurement result is described as traceable when it can be related to:

  1. the operator who took it
  2. the production lot number
  3. a national or international standard through an unbroken chain of calibrations Correct answer.
  4. the customer's purchase order

Explanation

Metrological traceability means an unbroken, documented chain of calibrations links the result to a recognized reference standard. Operator identity, lot number, and purchase order are administrative, not metrological, links.

Question 4Inspection Fundamentals and Terminology

In attribute inspection, a part is judged as:

  1. a numeric value on a continuous scale
  2. a calibrated reading in SI units
  3. conforming or nonconforming to a requirement Correct answer.
  4. a statistical mean of the lot

Explanation

Attribute inspection classifies each item into categories such as go/no-go or conforming/nonconforming. Variable inspection, by contrast, records numeric measurements on a continuous scale.

Question 5Inspection Fundamentals and Terminology

The act of confirming that a measurement instrument's readings agree with a reference standard within specified limits is called:

  1. calibration Correct answer.
  2. inspection
  3. gauging
  4. verification of product

Explanation

Calibration compares instrument output to a reference standard and documents the result. Product verification and inspection judge the item, not the instrument.

Question 6Inspection Fundamentals and Terminology

When an inspector uses a go/no-go gauge, the 'go' member should:

  1. not accept the part at any point
  2. be forced into the feature with hand pressure
  3. accept the part when it enters the feature Correct answer.
  4. only be used on rejected parts

Explanation

The go member is made to the maximum material limit and must pass through or onto the feature under its own weight. The no-go member, at the least material limit, should not enter.

Question 7Inspection Fundamentals and Terminology

A sampling plan used in receiving inspection primarily determines:

  1. the calibration interval of gauges
  2. the tolerance on the drawing
  3. the material specification of the part
  4. how many units to inspect and the accept/reject rule Correct answer.

Explanation

A sampling plan specifies sample size and the acceptance/rejection number based on the lot. Tolerances and material specs come from design, and calibration intervals from the metrology program.

Question 8Inspection Fundamentals and Terminology

An inspector measures a shaft with a micrometer and records 25.03 mm against a limit of 25.00 ± 0.02 mm. What is the correct disposition?

  1. Reject, since it exceeds the upper limit Correct answer.
  2. Re-measure until a passing value appears
  3. Accept, since micrometers are always accurate
  4. Accept, since it is within 0.05 mm

Explanation

The upper limit is 25.02 mm, so 25.03 mm is out of tolerance and the part is nonconforming. Measurement should never be repeated to obtain a favorable reading.

Question 9Inspection Fundamentals and Terminology

A gauge repeats the same reading on the same part but reads 0.04 mm high compared with a certified standard. This indicates:

  1. good repeatability and good accuracy
  2. good repeatability but poor accuracy Correct answer.
  3. poor repeatability and poor accuracy
  4. poor repeatability and good accuracy

Explanation

Repeatability concerns scatter between repeated readings, while accuracy concerns closeness to the true value. Consistent readings offset from the standard show low scatter but a systematic bias.

Question 10Inspection Fundamentals and Terminology

Which practice best preserves the integrity of inspection records?

  1. Backdating entries to match the production date
  2. Recording results in pencil so they can be corrected later
  3. Discarding original data once a summary is typed
  4. Making corrections with a single line, initials, and date Correct answer.

Explanation

Good documentation practice requires permanent media and traceable corrections showing who changed what and when. Erasable entries, destruction of raw data, and backdating all undermine record integrity.

Question 11Inspection Fundamentals and Terminology

A critical characteristic is one whose failure would:

  1. cause a hazard to safety or breach a regulation Correct answer.
  2. slightly increase rework cost
  3. affect only cosmetic appearance
  4. require a larger sample size

Explanation

Critical characteristics are those whose nonconformance could create a safety hazard or regulatory noncompliance, so they receive the tightest controls. Cosmetic and minor cost effects are lesser classifications.

Question 12Inspection Fundamentals and Terminology

The difference between the maximum and minimum permitted sizes of a feature is called the:

  1. basic size
  2. tolerance Correct answer.
  3. allowance
  4. deviation

Explanation

Tolerance is the total permissible variation, the difference between upper and lower limits. Basic size is the nominal reference, allowance is an intentional fit difference, and deviation is the offset from basic size.

Question 13Inspection Fundamentals and Terminology

In a variables sampling plan, the decision to accept a lot is based on:

  1. the visual appearance of the sample
  2. the calibration status of the gauge
  3. a statistic computed from measured values such as the mean and standard deviation Correct answer.
  4. the count of defective units only

Explanation

Variables plans use measured data, computing statistics like the sample mean and standard deviation to estimate lot quality. Attribute plans rely on defect counts, and appearance or calibration status are not the decision statistic.

Question 14Inspection Fundamentals and Terminology

An inspector finds a part with a scratch that does not exceed the cosmetic limit in the specification. The part should be:

  1. held pending engineering review
  2. scrapped without record
  3. accepted as conforming Correct answer.
  4. rejected as a defect

Explanation

A condition within the stated acceptance limit is conforming, so the part is accepted. Only conditions exceeding specified limits are nonconforming and require disposition.

Question 15Inspection Fundamentals and Terminology

The primary purpose of first article inspection is to:

  1. calibrate the measuring instruments
  2. count the number of parts in a lot
  3. replace all in-process inspection
  4. verify that the production process can produce parts meeting all requirements before full runs Correct answer.

Explanation

First article inspection validates the process, tooling, and documentation by fully evaluating an initial part against all requirements. It complements rather than replaces ongoing inspection and does not calibrate instruments.

Question 16Inspection Fundamentals and Terminology

A measurement system study reports that gauge repeatability and reproducibility (GR&R) is 28 percent of the tolerance. This result generally indicates:

  1. a marginal or unacceptable measurement system needing improvement Correct answer.
  2. that the tolerance should be widened
  3. that the parts are all nonconforming
  4. an acceptable measurement system for most purposes

Explanation

Common guidance treats GR&R below about 10 percent of tolerance as acceptable and above about 30 percent as unacceptable, with 10 to 30 percent marginal. A 28 percent result falls in the marginal band and warrants improvement.

Question 17Inspection Fundamentals and Terminology

Which statement correctly distinguishes inspection from testing?

  1. Testing is only visual, while inspection is only dimensional
  2. Inspection always destroys the item, while testing never does
  3. Inspection typically examines characteristics against criteria, while testing subjects the item to conditions to observe performance Correct answer.
  4. They are identical terms with no practical difference

Explanation

Inspection evaluates characteristics such as dimensions or appearance against specified criteria. Testing applies conditions like load, pressure, or voltage to observe functional performance.

Question 18Inspection Fundamentals and Terminology

A nonconforming item is segregated and tagged. The next required step in a typical quality system is to:

  1. ship it to the customer with a note
  2. discard the inspection record
  3. return it to the production line immediately
  4. disposition it through a documented process such as rework, repair, use-as-is, or scrap Correct answer.

Explanation

Nonconforming items must be controlled and formally dispositioned by authorized personnel. Returning to the line without disposition, shipping, or destroying records all bypass required controls.

Question 19Inspection Fundamentals and Terminology

An inspector must choose between a caliper with 0.02 mm resolution and a micrometer with 0.001 mm resolution for a tolerance of ±0.005 mm. The better choice is the micrometer because:

  1. it is faster to read
  2. its resolution is adequate relative to the tolerance while the caliper's is not Correct answer.
  3. it requires no calibration
  4. it is cheaper to purchase

Explanation

Measurement resolution should be a small fraction of the tolerance, commonly about one-tenth. A 0.02 mm resolution is far too coarse for a 0.010 mm total band, while 0.001 mm is suitable.

Question 20Inspection Fundamentals and Terminology

A lot is accepted under a sampling plan, yet it contains some nonconforming units. This outcome is best explained by:

  1. the inspector made an error
  2. the sampling plan is invalid
  3. the gauge was out of calibration
  4. sampling risk, since a sample cannot guarantee every unit conforms Correct answer.

Explanation

Acceptance sampling carries producer and consumer risk; an accepted lot may still contain defectives because only a sample was examined. This is inherent to sampling, not evidence of error.

Question 21Inspection Fundamentals and Terminology

A dimension is specified as 40.00 +0.05/-0.00 mm. An inspector records 40.00 mm. How should this reading be interpreted?

  1. It is above the upper limit and must be rejected
  2. It cannot be judged without a datum reference
  3. It is below the lower limit and must be rejected
  4. It is exactly at the lower limit and is acceptable Correct answer.

Explanation

The limits are 40.00 mm minimum and 40.05 mm maximum, so 40.00 mm sits exactly at the lower limit and conforms. Unilateral tolerances include the stated limit value.

Question 22Inspection Fundamentals and Terminology

Two inspectors measure the same part with the same gauge and obtain readings differing by 0.03 mm, while the gauge's GR&R reproducibility component is small. The most likely contributor is:

  1. appraiser variation from operator technique Correct answer.
  2. instrument resolution
  3. the material specification
  4. part-to-part variation

Explanation

When the gauge itself is consistent but different operators disagree, appraiser or operator variation is implicated. Technique differences in holding or reading the instrument are common causes.

Question 23Inspection Fundamentals and Terminology

An inspection plan requires 100 percent inspection of a safety-critical feature, yet the process is known to have a steady defect rate. The main limitation of 100 percent inspection here is:

  1. it guarantees zero escapes
  2. it is always less costly than sampling
  3. it eliminates the need for process control
  4. it is subject to human error and fatigue, so escapes can still occur Correct answer.

Explanation

Even full inspection is imperfect because of fatigue, inattention, and gauge limitations, so some escapes remain possible. It does not guarantee zero defects nor replace process control.

Question 24Inspection Fundamentals and Terminology

An inspector records a reading of 12.5 mm, but the gauge has a known systematic bias of +0.1 mm. The corrected value to report is:

  1. 12.4 mm Correct answer.
  2. 12.5 mm
  3. 12.6 mm
  4. 12.5 mm plus the tolerance

Explanation

A positive bias means the gauge reads high, so the bias is subtracted from the reading: 12.5 minus 0.1 equals 12.4 mm. Correcting for known systematic error improves accuracy.

Question 25Codes, Standards, and Regulatory Requirements

Which organization publishes the National Electrical Code (NFPA 70)?

  1. The National Fire Protection Association Correct answer.
  2. The American National Standards Institute
  3. The Institute of Electrical and Electronics Engineers
  4. The Occupational Safety and Health Administration

Explanation

The National Electrical Code is NFPA 70, developed and published by the National Fire Protection Association. OSHA and ANSI may adopt or reference it, but they do not author it.

Question 26Codes, Standards, and Regulatory Requirements

In the NEC article numbering system, which article covers wiring methods and materials?

  1. Article 500
  2. Article 300 Correct answer.
  3. Article 400
  4. Article 250

Explanation

Article 300 governs general requirements for wiring methods and materials. Article 250 covers grounding and bonding, Article 400 covers flexible cords, and Article 500 covers hazardous locations.

Question 27Codes, Standards, and Regulatory Requirements

A local jurisdiction adopts the NEC with amendments. What is the status of those amendments relative to the published NEC?

  1. They apply only to industrial occupancies
  2. They are void because the NEC is a federal law
  3. They are legally enforceable where adopted and take precedence locally Correct answer.
  4. They are advisory only and cannot override the NEC

Explanation

The NEC has legal force only through adoption by a jurisdiction, and adopting authorities may amend it. Local amendments are enforceable within that jurisdiction and govern over the unamended text.

Question 28Codes, Standards, and Regulatory Requirements

Which NEC article primarily addresses grounding and bonding requirements for electrical systems?

  1. Article 310
  2. Article 250 Correct answer.
  3. Article 210
  4. Article 230

Explanation

Article 250 contains the general requirements for grounding and bonding of electrical systems. Article 210 covers branch circuits, Article 230 services, and Article 310 conductors.

Question 29Codes, Standards, and Regulatory Requirements

The NEC is best described as which type of document?

  1. A manufacturer's installation manual
  2. A federal statute enacted by Congress
  3. A voluntary testing laboratory standard
  4. A model code intended for adoption by jurisdictions Correct answer.

Explanation

The NEC is a model code developed through consensus and given legal effect when adopted by a jurisdiction. It is not itself a federal statute or a manufacturer document.

Question 30Codes, Standards, and Regulatory Requirements

An inspector wants the standard that governs the required markings and ratings on electrical equipment nameplates. Which type of reference in the NEC would most directly apply?

  1. The contractor's scope of work
  2. A product standard referenced by the NEC Correct answer.
  3. The local building permit fee schedule
  4. The utility's rate tariff

Explanation

The NEC references product standards, often through listing requirements, that specify markings and ratings for equipment. Fee schedules, tariffs, and contracts do not define equipment marking requirements.

Question 31Codes, Standards, and Regulatory Requirements

Which body develops and publishes the standard for electrical installations in the United States that is most widely adopted as law?

  1. NEMA
  2. NFPA Correct answer.
  3. OSHA
  4. UL

Explanation

NFPA publishes NFPA 70, the National Electrical Code, which is the most widely adopted electrical installation code in the U.S. NEMA and UL publish product and equipment standards, and OSHA enforces workplace rules.

Question 32Codes, Standards, and Regulatory Requirements

A contractor installs equipment listed by a recognized testing laboratory. What does the NEC listing requirement primarily ensure?

  1. The installation will pass inspection without field verification
  2. The equipment has been evaluated to a recognized product standard Correct answer.
  3. The equipment was manufactured in the United States
  4. The equipment is the lowest-cost compliant option

Explanation

Listing means a qualified testing laboratory has evaluated the product against a recognized standard for its intended use. Listing does not guarantee the field installation is correct or address cost or origin.

Question 33Codes, Standards, and Regulatory Requirements

Which term describes the organization that has legal authority to enforce the electrical code in a given area?

  1. Listing agency
  2. Third-party inspector
  3. Authority having jurisdiction Correct answer.
  4. Standards developer

Explanation

The authority having jurisdiction (AHJ) is the organization empowered to enforce code requirements and approve installations. Listing agencies and standards developers do not enforce local code.

Question 34Codes, Standards, and Regulatory Requirements

An inspector is asked which edition of the NEC applies to a project. What is the most reliable basis for that determination?

  1. The edition referenced in a manufacturer's catalog
  2. The most recently published edition available
  3. The edition adopted by the jurisdiction with authority over the project Correct answer.
  4. The edition the contractor prefers

Explanation

The applicable edition is the one adopted by the governing jurisdiction, which may lag the newest publication. Neither publication date, contractor preference, nor a catalog determines legal applicability.

Question 35Codes, Standards, and Regulatory Requirements

Which NEC article covers requirements for electrical installations in hazardous (classified) locations?

  1. Article 400
  2. Article 300
  3. Article 250
  4. Article 500 Correct answer.

Explanation

Article 500 provides the classification and general requirements for hazardous locations. Articles 400, 300, and 250 cover flexible cords, wiring methods, and grounding, respectively.

Question 36Codes, Standards, and Regulatory Requirements

A plan reviewer notes that an installation must comply with both the NEC and a locally adopted fire code. How should conflicts between the two be resolved?

  1. Follow whichever document is newer
  2. Apply only the fire code to electrical work
  3. Ignore the fire code because the NEC is more specific
  4. Follow the more restrictive requirement unless the jurisdiction specifies otherwise Correct answer.

Explanation

Where multiple adopted codes apply, the generally accepted approach is to satisfy the more restrictive provision unless the jurisdiction provides a specific hierarchy. Neither recency nor specificity alone resolves the conflict.

Question 37Codes, Standards, and Regulatory Requirements

Which of the following best describes the role of the NEC in relation to OSHA regulations?

  1. OSHA writes the NEC for workplace enforcement
  2. OSHA regulations may reference the NEC as a recognized installation standard Correct answer.
  3. OSHA regulations apply only to residential work
  4. The NEC supersedes all OSHA regulations

Explanation

OSHA regulations can incorporate recognized consensus standards such as the NEC by reference for workplace electrical safety. OSHA does not author the NEC, and the two operate in different legal frameworks.

Question 38Codes, Standards, and Regulatory Requirements

Which document type is typically used by a jurisdiction to formally give the NEC the force of law?

  1. A product listing report
  2. A manufacturer's warranty
  3. A field inspection checklist
  4. An adoption ordinance or regulation Correct answer.

Explanation

A jurisdiction gives a model code legal effect through a formal adoption action such as an ordinance or regulation. Listing reports, checklists, and warranties do not create legal adoption.

Question 39Codes, Standards, and Regulatory Requirements

An installation complies with the NEC but violates a requirement in a locally adopted energy code. What is the most appropriate conclusion?

  1. The installation must satisfy both codes to be fully compliant Correct answer.
  2. The inspector should waive the energy code requirement
  3. The energy code requirement is unenforceable for electrical work
  4. NEC compliance alone is sufficient because it is the electrical code

Explanation

Separate adopted codes can impose independent requirements, and full compliance means meeting all applicable codes. NEC compliance does not excuse violations of other adopted codes.

Question 40Codes, Standards, and Regulatory Requirements

Which statement accurately describes the NEC's relationship to installation instructions provided with listed equipment?

  1. Instructions apply only when they match the NEC exactly
  2. Listed equipment must be installed in accordance with its listing and labeling instructions Correct answer.
  3. Instructions are enforceable only for industrial equipment
  4. Installation instructions are optional guidance that may be disregarded

Explanation

The NEC requires listed and labeled equipment to be installed in accordance with any instructions included in the listing or labeling. These instructions are part of the compliance basis, not optional advice.

Question 41Codes, Standards, and Regulatory Requirements

A designer cites a standard that the local jurisdiction has not adopted. What is the correct treatment of that standard in the permit review?

  1. It must be rejected entirely as irrelevant
  2. It may inform good practice but is not legally enforceable unless adopted or referenced Correct answer.
  3. It replaces the adopted code for that project
  4. It is automatically enforceable as a national consensus standard

Explanation

A standard has legal force only when adopted by the jurisdiction or incorporated by reference into an adopted code. Otherwise it may serve as guidance but is not independently enforceable.

Question 42Codes, Standards, and Regulatory Requirements

Which NEC article addresses branch-circuit requirements, including receptacle and lighting outlet provisions?

  1. Article 210 Correct answer.
  2. Article 240
  3. Article 250
  4. Article 220

Explanation

Article 210 covers branch-circuit requirements, including outlets and permissible loads. Article 220 covers calculations, Article 240 overcurrent protection, and Article 250 grounding.

Question 43Codes, Standards, and Regulatory Requirements

An owner asks whether a newer NEC edition can be applied voluntarily before the jurisdiction adopts it. What is the most accurate response?

  1. No, the NEC cannot be applied before formal adoption anywhere
  2. No, using a newer edition is prohibited
  3. Yes, but the legally enforceable standard remains the adopted edition Correct answer.
  4. Yes, and the newer edition automatically becomes enforceable

Explanation

A designer may choose to follow a newer edition as a matter of practice, but enforcement is based on the edition the jurisdiction has adopted. Voluntary use does not change the legal standard.

Question 44Codes, Standards, and Regulatory Requirements

Which of the following is a recognized testing laboratory function relevant to code compliance?

  1. Setting utility interconnection tariffs
  2. Issuing building permits
  3. Adopting the electrical code for a municipality
  4. Listing products as meeting a specific product safety standard Correct answer.

Explanation

Testing laboratories list products after evaluating them against applicable product standards. They do not adopt codes, issue permits, or set utility tariffs.

Question 45Visual and Dimensional Inspection

Which instrument is most appropriate for measuring the outside diameter of a small cylindrical pin to the nearest 0.01 mm?

  1. Tape measure
  2. Vernier caliper
  3. Steel rule
  4. Outside micrometer Correct answer.

Explanation

An outside micrometer provides a fine-resolution measurement of external diameters with typical resolution of 0.01 mm or better, making it the standard choice for small pins. Steel rules and tape measures are far too coarse, and a vernier caliper is less precise than a micrometer for small diameters.

Question 46Visual and Dimensional Inspection

On a metric vernier caliper, the main scale reads 24 mm and the vernier zero is just past it. The 7th vernier line aligns with a main-scale line on a 0.02 mm vernier. What is the reading?

  1. 24.14 mm Correct answer.
  2. 24.70 mm
  3. 24.02 mm
  4. 24.07 mm

Explanation

Each vernier division represents 0.02 mm, so the seventh aligned line adds 7 × 0.02 = 0.14 mm to the 24 mm main-scale reading. The total is therefore 24.14 mm.

Question 47Visual and Dimensional Inspection

A visual inspection of a machined surface reveals a regular pattern of fine parallel lines running in one direction. This condition is best described as:

  1. Flaking
  2. Waviness
  3. Lay Correct answer.
  4. Porosity

Explanation

Lay is the direction of the predominant surface pattern, typically produced by machining or grinding. It is a directional texture, not a defect, and is distinct from waviness (longer-wavelength deviation) and porosity (internal voids).

Question 48Visual and Dimensional Inspection

A part drawing specifies a dimension of 25.00 ± 0.05 mm. A measured part reads 24.94 mm. Which statement is correct?

  1. The part is out of tolerance because it is below the lower limit. Correct answer.
  2. The part is acceptable if the measurement uncertainty is small.
  3. The part is acceptable because tolerance applies only above nominal.
  4. The part is within tolerance because it is close to nominal.

Explanation

The limits are 24.95 mm to 25.05 mm, so a reading of 24.94 mm falls below the lower limit and is out of tolerance. Tolerance applies symmetrically around nominal unless stated otherwise.

Question 49Visual and Dimensional Inspection

Which of the following is a non-destructive visual inspection aid used to view surface details at magnified scale?

  1. Dye penetrant test
  2. Borescope Correct answer.
  3. Magnetic particle test
  4. Ultrasonic thickness gauge

Explanation

A borescope is an optical viewing device that allows visual inspection of internal or hard-to-reach surfaces without disassembly or damage. Magnetic particle and dye penetrant methods are separate NDT techniques, not optical magnification aids.

Question 50Visual and Dimensional Inspection

A straightness check is performed by placing a part on a surface plate and measuring the gap beneath a straightedge with feeler gauges. The maximum gap is 0.08 mm over a 200 mm length. What does this indicate?

  1. The surface has a straightness deviation of 0.08 mm. Correct answer.
  2. The straightedge is defective.
  3. The surface is flat within 0.08 mm over the measured length.
  4. The part thickness is 0.08 mm.

Explanation

The feeler-gauge gap under a straightedge directly indicates the straightness deviation, here 0.08 mm over the checked length. It measures deviation from a straight line, not overall flatness across the whole surface.