Electromagnetic Waves: Energy and Momentum

This lecture covers advanced concepts in electromagnetic waves, focusing on their energy and momentum. It begins with the energy of electromagnetic waves, introducing the Poynting vector, which describes the directional energy flux. The instructor explains the momentum of electromagnetic waves, detailing the relationship between energy density and momentum density. The discussion progresses to the generation of electromagnetic waves, including delayed potentials and the Hertz oscillator. The lecture also explores the Fabry-Perot interferometer, an optical instrument that analyzes interference patterns created by light waves. The instructor illustrates how light behaves when passing through a glass plate and calculates the resulting phase differences. Additionally, the lecture addresses Newton's rings, demonstrating how concentric interference patterns arise from a plano-convex lens. Finally, the pressure of radiation is derived through two approaches, emphasizing the interaction of electromagnetic waves with surfaces and the implications of radiation pressure in astrophysics. Overall, the lecture provides a comprehensive understanding of the fundamental principles governing electromagnetic waves and their applications.