This lecture covers the fundamental properties of electromagnetic (EM) waves, including their speed, refraction indices, and the relationship between frequency and wavelength. The instructor discusses the propagation speed of EM waves in various media, such as air, glass, and diamond, highlighting the significance of the refractive index. The lecture also delves into the frequency spectrum of EM waves, particularly focusing on FM waves and their mathematical representation. The instructor explains the wave equation and its components, emphasizing the importance of understanding wave behavior in different contexts. Additionally, the lecture touches on the concept of polarization, illustrating how EM waves can be polarized linearly or elliptically. The discussion includes practical examples and applications of these concepts in real-world scenarios, such as telecommunications and optical technologies. Overall, the lecture provides a comprehensive overview of the essential principles governing electromagnetic waves, making it a valuable resource for students in physics and engineering fields.