This lecture covers the applications of the first principle of thermodynamics, focusing on various transformations of ideal gases, including isothermal, isochoric, isobaric, and adiabatic processes. The instructor begins by discussing the importance of understanding these transformations and their implications in thermodynamics. The lecture provides definitions and examples for each type of transformation, explaining how they relate to the first principle. The instructor emphasizes the significance of heat capacities and how they differ for various gases. Throughout the lecture, practical examples and calculations are presented to illustrate the concepts, including the derivation of rules governing adiabatic transformations. The instructor also addresses student feedback regarding the course structure and noise levels in the classroom, ensuring a conducive learning environment. By the end of the session, students gain a comprehensive understanding of the rules governing transformations of ideal gases and their applications in real-world scenarios.