‘Thermodynamics’ is a chapter that has the unique property of being included in both Chemistry and Physics. Apart from the ‘difference in sign change’, you should note when energy is released from/absorbed into the system in both the Physics and Chemistry counterparts.
When you gain confidence in theory part then only move on to numericals. Start from basic problems from board textbooks or NCERT and then go up to advanced level problems from H. C. Verma and D. C. Pandey. Always try to get the sense of the question first, i.e. what it is telling you and what it wants from you. At JEE level, Thermodynamics mostly runs on the tip of formulae.
Let us find out how thermodynamics is important from JEE Physics perspective.
‘Heat & Thermodynamics’ contribute to about 3 to 4 questions in JEE Mains and 8-10% weightage in JEE Advanced. If you skip these chapters, you are going to be at a great loss. Thermodynamics is also very important for bachelor’s degree in Electrical, Mechanical, Civil, Chemical, or even Bio-Technology. In undergraduate engineering, thermodynamics is a common subject to all students in their first year.
Below is a list of good books on JEE Thermodynamics:
- NCERT Physics Textbook: NCERT textbook contains basic topics of Thermodynamics explained very well. It is important that you master all the ‘basics’ before moving on to more ‘Advanced Ideas’.
- Concepts of Physics (H. C. Verma): Go through the entire theory part, understand it well, and then attempt solved examples followed by the unsolved questions from each chapter under Thermodynamics (such as Calorimetry, Kinetic Theory of Gases, Heat Transfer and others). It is a BIBLE book and is necessary to form a strong base for each and every topic.
- Understanding Physics Series by D. C. Pandey (Arihant Publications): You will need this books for both reading the theory and practicing Advanced Level Problems. This book contains a large number of solved and unsolved examples on chapters of Thermodynamics. Open these books only once you have finished H. C. Verma and NCERT as then your basics will be clear.
- Problems in General Physics by I. E. Irodov or Fundamentals of Physics by Halliday & Resnick: These books are generally of a level above the general questions that are asked currently in JEE Advanced and may be considered optional. Give attempt to them only after you have finished above books.
- To complete your preparation, you are required to solve the past year JEE Thermodynamics questions to be aware of the pattern and type of questions asked (39 years Chapterwise Solved Paper by Arihant Publications).
Most important topics
- Kinetic theory of gases (questions on Ideal Gases are asked), Calorimetry (mainly principle based questions are asked in this), Heat conduction in one dimension, Elementary concepts of convection and radiation.
- Open, Closed and Isolated System, Understanding of System and Surroundings. State Variables & State Functions, Internal energy, Heat and work, Specific heat capacity. Detailed study of Isothermal, Isobaric, Isochoric and adiabatic processes.
- First law of Thermodynamics and its applications, Second law of thermodynamics, Carnot Cycle (very important for JEE Mains), Refrigerators and Heat Pumps, Reversible and Irreversible processes.
- Thermal equilibrium, Zeroth law of thermodynamics (Only application based problems are asked).
Some Basic Tips
- In thermodynamics, you will be dealing with quantities like pressure, temperature, internal energy, etc. These quantities as such describe the average behavior of a large number of molecules/atoms. Thus, mainly thermodynamics is concerned with macroscopic properties rather than microscopic properties of the system. For deep understanding of Thermodynamics, you must have good command over ‘theoretical knowledge’.
- Always make sure that Heat (Q), Internal Energy (U), and Work (W) are according to sign convection. Confusion in sign convention will lead to silly mistakes, wrong answer and ultimately fetch you negative marks.
- Mostly Questions are asked from topics such as Internal energy, Adiabatic & Isothermal process, Calorimetry, Heat Conduction. Questions are frequently asked from Isentropic process and Polytropic process. Pay extra attention to the major topics.
- Theoretical as well as numerical questions are asked from Thermodynamics based on finding work done by the cylinder-piston system. Sometimes the application of Laws of Thermodynamics is asked directly.
- Numerical type questions involve many steps & inter-related concepts, so you need to develop proper thinking ability and skill to approach towards the problem.
- Some chapters of Thermodynamics are common to both physics and chemistry. Theory part is mostly same in both, but they differ in sign convention, hence you are required to figure out the difference and similarity between the two so as to avoid the confusion and properly learn it.
- Try to make your own formulae sheet/diary to revise. Practice many Paragraph Type Questions and Multiple Choice Questions to understand and analyze your problem-solving ability. Many problems of Thermodynamics involve integral calculations, so you must know the basics of Integration.
- Thermodynamics mainly revolves around the physical changes in System & Surroundings. So to learn better with more interest you are required to understand its main objective and purpose. The formulas associated with are like roots to the solution. So maintain proper notes for this and revise the formulae on daily basis.
- The kind of questions that are asked in the Physics Thermodynamics are very practical and application based. Hence, are easily understandable as the learners can relate it to their day to day experiences. E.g. Refrigeration Systems & Heat Pumps work on the Second Law of Thermodynamics, boiling of water, pressure cookers, microwave oven heating are all thermodynamic processes. It is very important to visualize the questions in ‘real life form’ while trying to figure out solutions for many questions.
- Never be in a hurry to solve problems based on thermodynamics, read the question 2 or 3 times before attempting. Use approximation if possible such as the value of R (Universal Gas Constant) can be taken as 25/3 in place of 8.13 and similarly for other constants to make calculations easy.