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University Physics III

University Physics III · Thermodynamics · 7.02

Gas work, p-V paths, and path dependence

Work as the integral of p dV, the area under a p-V path, compression and expansion signs, the isothermal ideal-gas result nRT ln(V2/V1), and the quasi-static requirement this integral carries - one system pressure defined at every instant, which an irreversible process denies.

Course-map guide · not a complete lesson or simulation

Scope & orientation

What this subsection covers

Work as the integral of p dV, the area under a p-V path, compression and expansion signs, the isothermal ideal-gas result nRT ln(V2/V1), and the quasi-static requirement this integral carries - one system pressure defined at every instant, which an irreversible process denies.

A strong response uses temperature-entropy diagrams and states where the model stops being reliable.

Reasoning checklist

Evidence, assumptions and limits

01

Assumptions to state

State the system, observable, approximation, and conditions held fixed before using a model.

02

Evidence to collect

Two routes carry an ideal gas between the same two states; which computed quantities agree and which do not?

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Two routes carry an ideal gas between the same two states; which computed quantities agree and which do not? Useful evidence includes p-V and T-S paths for the reversible isothermal route with stage work and heat integrals, the free expansion plotted as endpoints only because its intermediate states are not equilibrium states, matching internal-energy and entropy changes across the two routes, the entropy generated in the free expansion, and grid-refinement checks.

03

Limits to state

This GioPhysics course map is an adaptable learning sequence, not academic credit, accreditation, or a universal university syllabus.

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This GioPhysics course map is an adaptable learning sequence, not academic credit, accreditation, or a universal university syllabus. Third-semester content is the least standardised of the introductory sequence: departments place oscillations, waves, optics, and thermal physics differently, and the modern-physics units here are a bounded survey rather than a complete course in relativity, quantum mechanics, atomic, nuclear, or particle physics. Follow your institution's published scope, notation, laboratory programme, and assessment rules. A result should be checked against units, signs, limiting cases, and the conditions under which its model was derived.

Diagram & examples

Work the claim before choosing an equation

Interactive concept map

Follow the model from claim to evidence.

01 · Physical claimGas work, p-V paths, and path dependence

Work as the integral of p dV, the area under a p-V path, compression and expansion signs, the isothermal ideal-gas result nRT ln(V2/V1).

Read the complete note

Work as the integral of p dV, the area under a p-V path, compression and expansion signs, the isothermal ideal-gas result nRT ln(V2/V1), and the quasi-static requirement this integral carries - one system pressure defined at every instant, which an irreversible process denies.

02 · RepresentationThe subsection's claim

Model, evidence, and boundary

03 · TestPrediction before measurement

What must be stated before selecting an equation for Gas work, p-V paths, and path dependence?

04 · Evidence & boundaryDecide, then qualify

Two routes carry an ideal gas between the same two states; which computed quantities agree and which do not?

Read the complete note

Two routes carry an ideal gas between the same two states; which computed quantities agree and which do not? Useful evidence includes p-V and T-S paths for the reversible isothermal route with stage work and heat integrals, the free expansion plotted as endpoints only because its intermediate states are not equilibrium states, matching internal-energy and entropy changes across the two routes, the entropy generated in the free expansion, and grid-refinement checks.

Interactive diagram for Gas work, p-V paths, and path dependence: follow the physical claim through its representation, proposed test, evidence, and model boundary.

modelModel, evidence, and boundary turns the stated idea into a representation that can make a prediction.

Example questions

Try the reasoning before revealing the structure.

Diagram check

What must be stated before selecting an equation for Gas work, p-V paths, and path dependence?

Quick check

Test the reasoning, not recall

What must be stated before selecting an equation for Gas work, p-V paths, and path dependence?

Choose an answer to test the model.