Zeroth Law of Thermodynamics

If A↔B and B↔C are in thermal equilibrium, then A↔C are too.

Concept

Zeroth Law of Thermodynamics is a foundational idea in this chapter. The defining relationship is:

$T_A = T_B = T_C$

This law gives meaning to 'temperature' as a measurable quantity.

Worked Application

Apply the formula to a typical problem from your textbook. Identify the knowns, plug into the equation, and check that the units work out. Always sanity-check the magnitude before accepting an answer.

Common Confusions

• Confusing the variables in the formula — re-read the symbol definitions in the chapter.
• Forgetting unit conversions (cm vs m, g vs kg).
• Ignoring sign conventions where direction matters.

Key Takeaways

• Master the formula $T_A = T_B = T_C$ and one canonical example.
• See the chapter index for full derivations, traps and exam-grade problems.