This lecture covers the boundary conditions between dielectrics, focusing on the normal and tangential components of D and E at material interfaces. It also introduces the right hand rule for Stokes' theorem and analyzes case studies involving dielectrics with no free charge. The analysis extends to electric field vectors, line integrals, and the comparison of boundary conditions between dielectrics. The instructor explains the behavior of potential difference in a charged capacitor and the impact of inserting a dielectric. The lecture concludes with a summary emphasizing the continuity of tangential components of E and the variation of normal components of D between dielectrics.