Skip to main content
Super TutorResources
Chapter 11 of 30
QuestionsNotesFlashcardsSummaryFormulasQuizConceptsSyllabusPlan
Revision Notes

Thermodynamics

NIOS · Class 12 · Physics

Quick revision notes for Thermodynamics — NIOS Class 12 Physics. Key concepts, formulas, and definitions for last-minute revision.

44 questions30 flashcards5 concepts

Interactive on Super Tutor

Studying Thermodynamics? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for revision notes and more.

Try Super Tutor — Free

1,000+ Class 12 students started this chapter today

A pressure-temperature (P-T) phase diagram for water, showing the solid, liquid, and gas regions, the triple point, and critical point.
Super Tutor

Super Tutor has 7+ illustrations like this for Thermodynamics alone — flashcards, concept maps, and step-by-step visuals.

See them all

Key Topics to Revise

1

Basic Concepts: Heat, Temperature, and Thermodynamic Systems

  • Heat is a form of energy that flows from a body at higher temperature to a body at lower temperature due to a temperature difference. It is NOT the same as internal energy.
  • Temperature is the property that determines whether two bodies are in thermal equilibrium. Two bodies in thermal equilibrium have the same temperature.
  • Unit of heat: 1 calorie = 4.18 Joules; 1 kcal = 1000 cal = 4180 J.
2

Thermodynamic Processes

  • Isothermal Process: Temperature is constant (ΔT = 0). Occurs in perfectly conducting cylinders. ΔQ, ΔU, and ΔW are all finite. For an ideal gas, ΔU = 0, so ΔQ = ΔW.
  • Adiabatic Process: No heat exchange (ΔQ = 0). Occurs in perfectly insulating cylinders. From First Law: ΔU = −ΔW. If gas is compressed, work is done ON the gas, ΔU increases (gas heats up). If gas exp
  • Isobaric Process: Pressure is constant (ΔP = 0). Example: Heating water under atmospheric pressure. Work done W = PΔV is non-zero.
3

Zeroth Law of Thermodynamics and Triple Point

  • Zeroth Law of Thermodynamics: If two bodies A and B are separately in thermal equilibrium with a third body C, then A and B are also in thermal equilibrium with each other.
  • The Zeroth Law introduces the concept of TEMPERATURE as a fundamental property. It is the scientific basis for thermometers.
  • Practical significance: A thermometer (body C) reads the same temperature when placed in contact with different bodies (A and B) that are in mutual thermal equilibrium.
4

Internal Energy and First Law of Thermodynamics

  • Internal Energy (U) is the sum of kinetic energy (random molecular motion) and potential energy (intermolecular forces) of all molecules in the system.
  • Internal energy is a STATE function — it depends only on the state (P, V, T) of the system, NOT on the path by which the state was reached.
  • Internal energy can be increased by: (1) Adding heat to the system, or (2) Doing work ON the system.

Get complete notes with diagrams and examples

Full Notes

Key Concepts

Heat is the form of energyA thermodynamic system is a definiteAn indicator diagram is a graphA system is in thermodynamic equilibriumFive major processes

Frequently Asked Questions

What are the important topics in Thermodynamics for NIOS Class 12 Physics?
Key topics in Thermodynamics include Solving a Numerical Problem — Systematic Approach, Mind map showing the major branches and concepts covered in the Thermodynamics chapter, Flowchart showing the direction of heat flow from hot body to cold body until thermal equilibrium is reached. These are the concepts NIOS Class 12 examiners draw on most — study them first, then practise related questions.
How to score full marks in Thermodynamics — NIOS Class 12 Physics?
Understand the core concepts first, then work through the 44 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

More resources for Thermodynamics

All 30 chapters — NIOS Class 12 Physics Revision Notes

For serious students

Get the full Thermodynamics chapter — for free.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for NIOS Class 12 Physics.

Try Super Tutor Free
Try the full chapter — Free