Energy is intimate to our existence. The energy that cooks our food, lights our houses and operates machines appears in its manifestation as heat released in burning of wood, coal, gas or oil. What is heat? How can we specify the direction of its flow? The answers to these and other related questions fall in the domain of **thermodynamics**. This subject came into existence on phenomenological basis long before we knew the nature of matter. Syllabus for IGNOU BSc Physics facilitate two distinct approaches to learn this subject. The **classical approach** is based on some postulates derived from experience. In the **statistical approach**, on the other hand, the firm physical and statistical basis of thermodynamics is demonstrated by relating the properties of bulk systems to the behavior of their elementary constituents.

One of the oldest hypotheses is that matter is made up of molecules. The interplay between intemolecular forces and thermal agitation gave birth to the molecular theory, which when supplemented by the laws of mechanics for individual molecules leads to kinetic theory. It enables us to relate macroscopic and microscopic properties of gases. In a sense, kinetic theory has great aesthetic appeal in that elegant laws govern the chaotic motion of a large number of molecules. Moreover, this theory finds useful applications in frontal areas of physics.

In classical statistical mechanics, we supplement purely statistical methods by the laws of (classical) mechanics for individual particles making up the system. The advent of quantum mechanics gave it a new shape. Many new phenomena, completely unknown in the domain of classical statistical physics, can be satisfactorily explained. The working of lasers, physics of superconductivity and superfluidity is much well understood now.

In its present state, thennodynamics and statistical mechanics is one of the most fascinating courses taught to undergraduate physics students. It finds use in material science, engineering, chemistry, quantum, atomic and molecularphysics, spectroscopy, energy studies and beyond. It provides opportunities to develop a sensibility towards nature; the essential part of physics education. Therefore, a more thoughtful study will bring you extra rewards!

## Syllabus per Block Divisions in IGNOU BSc Physics - Thermodynamics and Statistical Mechanics PHE-06

### Block 1: The Zeroth and The First Laws of Thermodynamics

**Unit 1:**Basic Concepts of Themodynamics**Unit 2:**Measurement of Temperature**Unit 3:**The First Law of Themodynamics**Unit 4:**Applications of the First Law of Themodynamics

### Block 2: The Second and The Third Laws of Thermodynamics

**Unit 5:**Entropy and the Second Law of Thermodynamics**Unit 6:**The Theimodynamic Potentials**Unit 7:**Phase Transitions**Unit 8:**Production of Low Temperatures and the Third Law

### Block 3: Elementary Kinetic Theory

**Unit 9:**Ideal Gases**Unit 10:**Transport Phenomena**Unit 11:**Brownian Motion**Unit 12:**Real Gases

### Block 4: Elements of Statistical Mechanics

**Unit 13:**Basic Concepts of Statistical Mechanics**Unit 14:**The Partition Function**Unit 15:**Quantum Statistics**Video:**Thermodynamics in action

## Detailed Syllabus for IGNOU BSc Physics - Thermodynamics and Statistical Mechanics PHE-06

Thermodynamic Systems and Classification of their Boundaries; Thermodynamic State of a System and Thermodynamic Variables; Thermodynamics Processes: Reversible and Irreversible and Quasistatic Processes, Representation of a Thermodynamic Process, Zeroth Law of Thermodynamics, Equation of State, Deduction from Equation of State; Principle of Measurement of Temperature, Physical Properties and Scale of Temperature, Types of Thermometers: Constant Volume Gas Thermometer, Platinum Resistance Thermometer, Thermistors, Thermocouples; Radiation Pyrometers, The International Temperature Scale; Nature of Heat and Work, Internal and External Work, Work done in Different Systems, Path Dependence of Work and Heat, Internal Energy, The First Law of Thermodynamics, its Differential Form and Significance; Heat Capacities of a Gas, Equation of State for Adiabatic Processes, The Adiabatic Lapse Rate: Convective Equilibrium, Adiabatic and Isothermal Elasticities, The Enthalpy, Enthalpy and Chemical Processes, Standard Enthalpy Changes, Enthalpy of Reaction, Hess's Law (statement only).

Entropy; The Second Law of Thermodynamics: Entropy Change in Natural Processes, The Carnot Cycle: Heat Engines and Refrigerators; The Thermodynamic Temperature Scale; The Thermodynamic Potential Functions, General Conditions for Thermodynamic Equilibrium; Maxwell's Relations in Thermodynamics, Deductions from Maxwell's Equations, TdS- Equations, Energy Equations, Heat Capacity Equations; Phase Equilibrium, The Condition for Equilibrium between Phases, First Order Phase Transitions, Higher Order Phase Transitions, Gibbs' Phase Rule; Different Methods of Cooling, Joule-Thomson Effect, Liquefaction of Gases, Liquid Helium; Cooling by Adiabatic Demagnetization; The Third Law of Thermodynamics.

Kinetic Theory of Gases, Kinetic Interpretation of Temperature, Elementary Deductions, Law of Equipartition, Classical Theory of Specific Heats; Mean Free Path, Distribution of Free Paths, Experimental Determination, Viscosity, Thermal Conductivity, Self Diffusion; Random Walk, Brownian Motion, Einstein's Theory, Langevin's Theory, Avogadro Number, Examples of Brownian Motion; Deviations from Perfect Gas Behaviour, Regnault's, Andrews'and Amagat's Experiments, Onnes' Equation of State, Claussius and Van Der Waals Equation of State, Critical Constants, Law of Corresponding States.

Phase space, Microscopic and Macroscopic States, Thermodynamic Probability, Entropy- Thermodynamic Probability Relation, Classical Distribution Function, Partition Function; Partition Function for a Monatomic Gas, Law of Equi-partition of Energy, Calculation of Thermodynamic Parameters, Sekur-Tetrode Equation, Gibbs Paradox, Heat Capacity of Hydrogen, Rotational and Vibrational Partition Functions; Need for Quantum Statistics, Bose- Einstein Distribution Function, Planck's law, Radiation Pressure, Bose-Einstein Condensation, Fermi-Dirac Distribution Function, Fermi Energy, Heat Capacity of Metals.