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Showing 211–240 of 1709 reference entries

PhysicsRC charging and discharge

A simple resistor–capacitor circuit has an exponential timescale.

ModelPhysicsSeries RLC impedance magnitude

Sinusoidal response combines resistance and net reactance.

ModelPhysicsFourier heat conduction

A temperature gradient drives conductive heat flux.

ModelPhysicsLatent heat of a phase transition

Energy changes phase at the specified coexistence conditions.

ModelPhysicsApproximate vapor-pressure relation

Vapor pressure changes with temperature through latent enthalpy.

ModelPhysicsBlackbody total emission

Thermal equilibrium fixes an ideal absorber's total emitted power.

ModelPhysicsCanonical thermal ensemble

Fixed-temperature equilibrium weights states by energy.

ModelPhysics · InformationGibbs entropy

Microstate probabilities quantify statistical entropy.

DefinitionPhysicsQuantum observable expectations

A state and observable determine the mean of repeated outcomes.

ModelPhysicsRobertson uncertainty relation

A commutator constrains two outcome spreads in the same state.

ModelPhysicsSpin one-half and Pauli operators

A spin one-half state has two outcomes along a chosen axis.

ModelPhysics · InformationPure and mixed density operators

A density operator represents quantum statistical states.

DefinitionPhysicsIdeal projective measurement

Projectors determine outcome probabilities and conditional states.

ModelPhysics · InformationComposite states and entanglement

A joint pure state can fail to factor into subsystem states.

DefinitionPhysicsExchange symmetry of identical particles

Boson and fermion states respond differently to exchange.

ModelPhysics · Mathematics & logicGeodesic motion

Free test motion follows the metric connection.

ModelPhysicsEinstein gravitational field equations

Spacetime curvature responds to stress and energy.

ModelPhysicsSchwarzschild static-observer redshift

Clocks at different radii measure different light frequencies.

ModelPhysics · Earth & cosmosFriedmann cosmological evolution

Homogeneity and isotropy reduce gravitational expansion to two balances.

ModelMeasurementCalibration

Relate indications to standards, then infer measurement results.

DefinitionMeasurementType A and Type B uncertainty evaluation

The classification describes how a component is evaluated.

MethodMeasurementExpanded uncertainty and coverage

A coverage factor scales standard uncertainty to a reported interval.

MethodMeasurement · Mathematics & logicCovariance in uncertainty models

Shared input variation belongs in the joint uncertainty description.

MethodMeasurementMeasurement models

Specify how input quantities determine the measurand.

MethodMeasurement · InformationMonte Carlo uncertainty propagation

Sample the joint input model to approximate the output distribution.

MethodMeasurementRepeatability and reproducibility

Precision depends on which measurement conditions are held or changed.

DefinitionMeasurementResolution and sensitivity

Detectable change and response scale are different instrument properties.

DefinitionMeasurementDynamic instrument response

Response depends on timescale, gain and phase.

MethodPhysicsHydrogen Coulomb energy levels

The ideal one-electron atom has discrete bound energies.

ModelPhysics · ChemistryAtomic state labels and Pauli occupancy

Quantum labels specify orbitals and spin states.

Model
ModelSource checked

Latent heat of a phase transition

Physics

Energy changes phase at the specified coexistence conditions.

Key knowledge

For mass m undergoing a specified equilibrium transition at fixed pressure, the latent heat magnitude is Q = mℓ. Fusion and vaporization absorb heat; their reverse transitions release it.

Values and equations

|Q_phase| = mℓ

Q_phase
Heat transferred for the phase change J
m
Transformed mass kg
ℓ
Specific latent enthalpy magnitude J kg⁻¹

Conditions and scope

  • ℓ is specific latent enthalpy at the stated pressure and coexistence temperature; only pressure–volume work is allowed and sensible heating is accounted separately.
  • The sign of heat into a system must be specified; no pressure-independent universal ℓ is assumed.
  • Use a closed system with negligible changes of bulk kinetic and gravitational potential energy, and a mechanically quasistatic transition at constant pressure; no additional work modes are included.
  • The heat-absorption labels for fusion and vaporization assume positive specific enthalpy change for those forward transitions. Heat-transfer direction follows the actual phase enthalpy change; the displayed magnitude alone does not determine its sign.
Sources · 4

References

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

  1. University Physics 2: Phase ChangesSamuel J. Ling, Jeff Sanny and William Moebs / OpenStax, Rice UniversityTextbook chapteropenstax.orgRead source
  2. Massachusetts Institute of Technology2 sources
    1. Thermodynamics and Propulsion, §2.1: First Law of ThermodynamicsMassachusetts Institute of Technology — Unified Engineering course notesCourse notesweb.mit.eduRead source
    2. Unified Thermodynamics: Lecture T4 first-law and enthalpy clarifications (2003)Massachusetts Institute of Technology — MIT OpenCourseWareCourse notesocw.mit.eduRead source
  3. Thermal Properties of Matter · Physics (2026–27 reprint)National Council of Educational Research and Training (NCERT)Textbook chapter · PDFncert.nic.inRead source

Evidence and review

Fusion/vaporization heat equations and reverse-transition discussion.

Phase-change heat equals the enthalpy change for the stated stationary closed system with negligible bulk kinetic and gravitational potential energy changes and quasistatic constant-pressure work.

2026-10-10 · Independent Chemistry, Biology and Earth/Cosmos editor (AI editorial review). Source checks and independent AI editorial review of compact reference claims, equations, units, conditions and conceptual mappings. This is not human specialist certification, laboratory accreditation, whole-book verification, or a claim that all possible foundational knowledge is present.

Foundational review

2026-10-10 · Fresh primary-source inspection of the complete compact record, including every statement, equation, quantity and material condition, followed by independent AI editorial review. This check does not certify all linked lessons or every passage of every cited publication.

Sources from other places

Scope or convention differs

Ordinary equilibrium melting and vaporization use pressure-dependent latent heat with magnitude mℓ; the reverse process releases heat.

The compact school formula does not state every work-path restriction; ARK keeps the fixed-pressure, closed-system qualifications.

Related reference entries

Explore relationships within this area of study and its connections to other areas.

Showing 1–3 of 3 relationships

Scientific relationships · 3 / 3

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

  1. Related to
    Relationship sources · 3

    Linked statements

    • For mass m undergoing a specified equilibrium transition at fixed pressure, the latent heat magnitude is Q = mℓ. Fusion and vaporization absorb heat; their reverse transitions release it.

    For a closed system with negligible bulk kinetic/gravitational potential energy changes, a mechanically quasistatic constant-pressure transition with only pressure–volume work has heat equal to its enthalpy change.

  2. Uses definition
    Relationship sources · 1

    Linked statements

    • For liquid–vapor equilibrium with ideal dilute vapor, negligible liquid molar volume and approximately constant molar vaporization enthalpy ΔH_vap, ln(p₂/p₁) = −(ΔH_vap/R)(1/T₂ − 1/T₁).

    Molar vaporization enthalpy in the integrated ideal-vapor coexistence approximation.

  3. Uses definition
    Relationship sources · 1

    Linked statements

    • Heat names energy transfer caused by a temperature difference, rather than a substance stored in an object. Temperature and internal energy are different state quantities. For a fixed mass heated along a specified process without a phase transition, Q=m∫c(T)dT; if the process-specific c is nearly constant, Q≈mcΔT. Pressure and volume constraints can give different specific heats.

    This relation concerns the stated heat, temperature and specific heat claim and its conditions; it does not assert an unqualified prerequisite or an additional theorem.

Entry detailsPermanent link to this entry ↗
Record identity
physics-latent-heat
Revision
foundations-audit.1
Structured reference record
University reference · University core expansion