Thermal Physics is one of those units in Physics that is sure to act as your masterstroke during exams, if worked on properly.
WHAT IS INTERESTING ABOUT IT?
Well, HEAT being a form of energy is something with which we are surrounded every time The practical applications of this unit are very wide. From heating up your pizzas to the melting of ice in Arctic and the various instruments like thermoscopes, thermometers, thermograms, etc that are governed by the temperature and radiation. Do you know about infrared radiation? An instrument thermogram gives colour-coded heat content of any body – white and red indicating the greatest radiation rate. You must have seen it on the Discovery Channel. Well, it is interesting to note how temperature can be judged from the radiations from a body. HEAT can be transformed, transferred and absorbed. The more you explore about it, the more interesting its study gets.
HANDLING THE SECTIONS
- Heat flow can be made easy by taking heat flow analogous to current flow in electricity and coefficient of thermal conductivity analogous to resistivity. I’m sure your physics teacher might have taught you this. To those who ignored it finding it inappropriate to complicate heat with electricity, trust me, this method is way too useful.
- KTG – A very very important part. Be thorough with NCERT. Minute pieces of info like, dependency of mean free path on pressure or temperature can be asked…be prepared !
- RADIATION LAWS – Stefan’s law, Wien’s displacement law and topic such as emissive and absorbtive powers of black body are important topics you should know. Many questions can be solved if you know the definitions of these terms clearly.
- THERMODYNAMIC PROCESSES – This one is a simple yet highly logical topic. You should maintain a good grip over all the processes along with the graphical relations. Graphs are something most frequently asked by JEE under this section.
- Latent heat, Specific heat at constant pressure and Specific heat at constant volume forms an important part. After this comes the degree of freedom part. All this is pretty easy if you have done it already in Chemistry.
However, focus should be on how questions are framed using these sections. For example,paper setters basically mix the concept of specific heats of monoatomic or diatomic gas with the thermodynamic process taking place with the gas. Easy…..right? Only if you are clear with the basics. Memorizing the formulae will only help you for JEE Main but it is the concepts coupled with inense practice that will sail you through JEE Advanced.
WHAT IF I KNOW ALL THE CONCEPTS YET FAIL TO APPLY THEM IN TRICKY QUESTIONS? …I would say…..Practice and practice more till you are finally able to attempt the previous years’ questions easily and accurately( the latter being more important 🙂 ). There is a high probability that you end up making SILLY MISTAKES or ignoring subtle small but relevant points.
BOOKS: If you are good with thermal physics, good as in if you are able to solve any question from this section without making mistakes and given any new question, you are able to think of the concept to be applied; follow HC Verma-II and NCERT. …If you feel a need to prepare more, then go solve I.E. Irodov : Problems in General Physics.