Paul Peter Urone; Roger Hinrichs

Skip to Content Go to accessibility page Keyboard shortcuts menu

Key Equations

PhysicsKey Equations

12.2 First law of Thermodynamics: Thermal Energy and Work

ideal gas law	$P V = N k T$
first law of thermodynamics	$Δ U = Q - W$
pressure	$P = \frac{F}{A}$
pressure–volume work	$W = P Δ V$

12.3 Second Law of Thermodynamics: Entropy

change in entropy

Δ S = \frac{Q}{T}

12.4 Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators

thermal efficiency of a heat engine	$E f f = \frac{W}{Q_{h}}$
work output for a cyclical process	$W = Q_{h} - Q_{c}$

Previous Next

Order a print copy

Citation/Attribution

This book may not be used in the training of large language models or otherwise be ingested into large language models or generative AI offerings without OpenStax's permission.

Want to cite, share, or modify this book? This book uses the Creative Commons Attribution License and you must attribute Texas Education Agency (TEA). The original material is available at: https://www.texasgateway.org/book/tea-physics . Changes were made to the original material, including updates to art, structure, and other content updates.

Attribution information

If you are redistributing all or part of this book in a print format, then you must include on every physical page the following attribution:
Access for free at https://openstax.org/books/physics/pages/1-introduction
If you are redistributing all or part of this book in a digital format, then you must include on every digital page view the following attribution:
Access for free at https://openstax.org/books/physics/pages/1-introduction

Citation information

Use the information below to generate a citation. We recommend using a citation tool such as this one.
- Authors: Paul Peter Urone, Roger Hinrichs
- Publisher/website: OpenStax
- Book title: Physics
- Publication date: Mar 26, 2020
- Location: Houston, Texas
- Book URL: https://openstax.org/books/physics/pages/1-introduction
- Section URL: https://openstax.org/books/physics/pages/12-key-equations

© Jun 7, 2024 Texas Education Agency (TEA). The OpenStax name, OpenStax logo, OpenStax book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the Creative Commons license and may not be reproduced without the prior and express written consent of Rice University.