Statistical Definition of Entropy

This lecture explores the statistical definition of entropy, revealing the true reason behind the second law of thermodynamics and discussing the third principle of thermodynamics. By analyzing the microscopic interpretation of Joule's expansion, the instructor explains the concept of entropy as a measure of multiplicity and probability of macroscopic states. The lecture demonstrates the equivalence between macroscopic and microscopic entropy, highlighting the importance of maximizing probability in natural processes. Through examples like Joule's expansion and coin tossing, the lecture elucidates why improbable events never occur in nature due to the vast number of particles involved. Additionally, it delves into the concept of zero entropy, which corresponds to absolute zero temperature according to the Nernst principle, the third law of thermodynamics.