CCT sample questions

Question 1

A commercial calibration laboratory is updating its quality manual to explicitly define how measurement traceability is realized and disseminated. Which TWO of the following statements correctly describe acceptable paths or principles for establishing unbroken traceability to the International System of Units (SI)? (Select TWO)

Accepted Answer

Utilizing calibration services from an ISO/IEC 17025 accredited laboratory whose scope covers the required measurement.

Accepted Answer

Procuring primary reference materials directly from a recognized National Metrology Institute (NMI) such as NIST.

Answer

Comparing the working standard directly against any uncalibrated intrinsic standard without documented uncertainty.

Answer

Relying solely on the original equipment manufacturer's (OEM) initial factory certificate of conformance, regardless of age or accreditation.

Answer

Establishing traceability through a consensus standard that lacks mathematical relationship to SI base units.

Question 2

During a high-workload period, a laboratory's primary reference pressure controller is sent out for its annual calibration. The technical manager must decide if a secondary transfer standard can be substituted to calibrate a customer's working gauge. The customer's gauge has a stated accuracy of ±0.25% of full scale. The proposed substitute standard has an expanded uncertainty of ±0.10% of full scale. Based strictly on standard industry practices for Test Uncertainty Ratios (TUR), what is the correct evaluation of this substitution?

Accepted Answer

The substitution is marginal and typically requires customer concession, as it only yields a 2.5:1 TUR, falling short of the generally preferred 4:1 ratio.

Answer

The substitution is completely invalid because secondary transfer standards can only be used to calibrate reference standards, never working equipment.

Answer

The substitution is highly optimal, as it provides a 10:1 TUR, fully satisfying stringent military and aerospace requirements.

Answer

The substitution is acceptable without further evaluation because any secondary standard automatically supersedes a working gauge in the hierarchy.

Question 3

True or False: In the revised International System of Units (SI), the value of the speed of light in a vacuum (c) is no longer an exact defined constant, but is instead an experimentally determined value subject to measurement uncertainty.

Accepted Answer

False

Answer

True

Question 4

A calibration procedure for an electrometer requires a test current of 500 nanoamperes (nA). The available source only allows input in microamperes (µA). The correct input value to achieve the required test current is: ________ µA.

Accepted Answer

0.5

Answer

5000

Answer

5.0

Answer

0.05

Question 5

A metrology lab maintains a strict hierarchy of standards to minimize wear on their most accurate equipment while maintaining traceability down to the production floor.

Based on the typical dissemination hierarchy shown in the diagram below, which type of standard belongs in the position marked '[ ? ]'?

```mermaid
flowchart TD
NMI[National Metrology Institute 
 e.g., NIST] --> Primary[Primary Standard]
Primary --> Ref[Reference Standard]
Ref --> Missing["[ ? ]"]
Missing --> Working[Working Standard]
Working --> UUT[Unit Under Test / IM&TE]
```

Accepted Answer

Transfer Standard

Answer

Derived Standard

Answer

Consensus Standard

Answer

Intrinsic Standard

Question 6

A calibration engineer is analyzing the performance of a new digital micrometer. They have the same technician measure the exact same gage block 15 times in a row, within a span of 10 minutes, in a tightly temperature-controlled room. The variation observed in these 15 measurements is primarily an indication of which measurement characteristic?

Accepted Answer

Repeatability

Answer

Linearity

Answer

Reproducibility

Answer

Stability

Free CCT sample questions

True or False: In the revised International System of Units (SI), the value of the speed of light in a vacuum (c) is no longer an exact defined constant, but is instead an experimentally determined value subject to measurement uncertainty.

A calibration procedure for an electrometer requires a test current of 500 nanoamperes (nA). The available source only allows input in microamperes (µA). The correct input value to achieve the required test current is: ________ µA.

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