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Showing 1591–1620 of 1709 reference entries

PhysicsSpecular and diffuse reflection

Reflection angles are measured from the local normal.

ModelPhysicsTotal internal reflection and evanescent fields

Total reflected flux does not mean zero field beyond the interface.

ModelPhysicsSpherical-mirror images and signs

A virtual image is formed by ray extensions, not actual ray convergence.

ModelPhysicsPhotoelectric threshold and stopping potential

Photon frequency sets maximum photoelectron energy in the single-photon model.

ModelPhysicsDe Broglie wavelength and particle momentum

A momentum state has a spatial wave phase.

ModelMeasurementQuantity kind and physical dimension

Equal dimensions do not make quantities interchangeable.

DefinitionMeasurementQuantity value, numerical value and unit

A numerical value depends on the chosen unit.

DefinitionMeasurementCoherent derived units

Coherence means no extra numerical factor in the base-unit product.

DefinitionMeasurementOrdinal quantities and nominal properties

Ordering and category labels do not justify ordinary arithmetic.

DefinitionMeasurementMeasurement principle, method and procedure

A physical phenomenon, an approach and a detailed procedure have different roles.

DefinitionMeasurementMeasuring instrument and measuring system

A complete measurement system can include more than one device.

DefinitionMeasurementSensor, transducer and detector

Component names describe different measurement roles.

DefinitionMeasurementInstrument indication and measurement result

A displayed reading is only one part of a measurement result.

DefinitionMeasurementAdjustment, calibration and zero adjustment

Changing an instrument response differs from determining its calibration.

DefinitionMeasurementReference and conventional quantity values

An accepted comparison value need not be an exact true value.

DefinitionMeasurementIndication interval, measuring interval and span

Possible readings differ from a validated interval of measurement.

DefinitionMeasurementRated operating conditions

Instrument properties are specified within a domain of use.

DefinitionMeasurement · ChemistrySelectivity of a measuring system

Responding to a target differs from excluding interference.

DefinitionMeasurementDiscrimination threshold and dead band

An undetected input change differs from an interval with no output change.

DefinitionMeasurementStability of a measuring instrument

Time stability differs from short-term repeatability.

DefinitionMeasurementMaximum permissible error and accuracy class

A specification limit is not an uncertainty estimate.

DefinitionMeasurementDefinitional uncertainty

More repetitions do not resolve an underspecified measurand.

DefinitionMeasurementRelative standard uncertainty

Relative uncertainty uses a nonzero measured magnitude.

DefinitionMeasurementBlank indications and null measurement uncertainty

A zero or blank reading can still have uncertainty.

DefinitionMeasurementTarget measurement uncertainty

An intended-use target differs from achieved uncertainty.

DefinitionMeasurementIntermediate precision conditions

Within-location changed conditions differ from strict repeatability.

DefinitionMeasurementCommutability of a reference material

Certification alone does not establish equivalence across procedures.

DefinitionChemistrySubstances, elements, compounds and mixtures

Chemical composition and spatial uniformity describe different features of matter.

DefinitionChemistryPhysical change and chemical change

A change of phase need not change chemical identity.

DefinitionChemistryEmpirical, molecular and structural formulas

A formula's subscripts represent different information in different chemical models.

Definition
DefinitionSource checked

Instrument indication and measurement result

Measurement

A displayed reading is only one part of a measurement result.

Key knowledge

An indication is a quantity value provided by a measuring instrument or system. A measurement result is the set of quantity values attributed to the measurand together with relevant available information; ordinarily it includes a measured value and its uncertainty. The indicated quantity may differ in kind from the inferred measurand, so a reading can require conversion through the measurement model.

Conditions and scope

  • The indication can be visual, recorded or otherwise supplied, not only a digital display.
  • Do not assume the display digits define the measurand, establish traceability or equal the reported uncertainty. Nominal-property determinations require their own result representation.
Sources · 2

References

Sources retain their recorded scope. A source link alone does not establish verification of every statement.

  1. International Vocabulary of Metrology (VIM3)Joint Committee for Guides in Metrology (JCGM)Reference guideVIM3, entry 4.1VIM3, entry 2.9jcgm.bipm.org

Evidence and review

Read VIM4.1 definition and notes on indication representation/different quantity kinds, and2.9 definition/notes on value sets and uncertainty. The inference caveat is the connection to the existing measurement model, not a new error correction formula.

2026-10-10 · /root/audit_life_earth_chemistry — independent Chemistry/Life/Earth editor. Independent AI editorial review of this entry's statements, equations, applicability conditions and source coverage. Source checks apply to these claims within their stated limits.

Related reference entries

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Showing 1–6 of 6 relationships

Scientific relationships · 6 / 6

The relationship type describes the connection. Its linked statements, sources and conditions define the scope.

  1. Related to
    Relationship sources · 2

    Linked statements

    • An indication is a quantity value provided by a measuring instrument or system. A measurement result is the set of quantity values attributed to the measurand together with relevant available information; ordinarily it includes a measured value and its uncertainty. The indicated quantity may differ in kind from the inferred measurand, so a reading can require conversion through the measurement model.

    The two records describe related physical or metrological models or distinctions; the present claim does not require every hypothesis or result in the linked record.

  2. Uses definition
    Relationship sources · 2

    Linked statements

    • An indication is a quantity value provided by a measuring instrument or system. A measurement result is the set of quantity values attributed to the measurand together with relevant available information; ordinarily it includes a measured value and its uncertainty. The indicated quantity may differ in kind from the inferred measurand, so a reading can require conversion through the measurement model.

    This relation concerns the stated instrument indication and measurement result claim and its conditions; it does not assert an unqualified prerequisite or an additional theorem.

  3. Related to
    Relationship sources · 2

    Linked statements

    • An indication is a quantity value provided by a measuring instrument or system. A measurement result is the set of quantity values attributed to the measurand together with relevant available information; ordinarily it includes a measured value and its uncertainty. The indicated quantity may differ in kind from the inferred measurand, so a reading can require conversion through the measurement model.

    The two records describe related physical or metrological models or distinctions; the present claim does not require every hypothesis or result in the linked record.

  4. Uses definition
    Relationship sources · 2

    Linked statements

    • Adjustment comprises operations that make a measuring system provide prescribed indications for given values of the measured quantity. Zero adjustment is the adjustment producing a null indication for a zero value. Calibration is a prerequisite for adjustment and is usually required again afterwards; adjustment must not be called calibration. Setting zero alone does not establish correct gain, response across the interval or zero uncertainty.

    This relation concerns the stated adjustment, calibration and zero adjustment claim and its conditions; it does not assert an unqualified prerequisite or an additional theorem.

  5. Uses definition
    Relationship sources · 3

    Linked statements

    • An indication interval is bounded by the extreme possible indications. Its span is the absolute difference between those extremes. A measuring interval is the set of quantity values measurable with a specified instrumental uncertainty under defined conditions. A ±10V indication interval has20V span, but that interval alone does not establish a20V measuring capability. The lower limit of a measuring interval need not equal a detection limit.

    This relation concerns the stated indication interval, measuring interval and span claim and its conditions; it does not assert an unqualified prerequisite or an additional theorem.

  6. Uses definition
    Relationship sources · 2

    Linked statements

    • A blank indication is obtained for a phenomenon, body or substance similar to the investigated one but with the quantity of interest assumed absent or not contributing. Null measurement uncertainty is associated with a null or near-zero measured quantity value. Neither a blank nor a null indication guarantees zero uncertainty; subtracting a blank requires the measurement model and the uncertainties and any covariance of the sample and blank results.

    This relation concerns the stated blank indications and null measurement uncertainty claim and its conditions; it does not assert an unqualified prerequisite or an additional theorem.

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