This lecture covers the wave equation for electromagnetic fields, derived from Maxwell's equations in vacuum. It explains how variable electric fields can create magnetic fields, leading to the continuous propagation of electromagnetic waves in vacuum. The lecture also delves into the fundamental velocity of light, the wave equation for both electric and magnetic fields, and the solutions for harmonic waves. Additionally, it explores the properties of electromagnetic waves, such as their transverse nature, coupled E and B fields, and the concept of polarization.