This series on geometric optics covers the fundamental principles and concepts of how light behaves, including reflection and refraction phenomena. Our exploration begins with an introduction to the behavior of light rays, followed by an in-depth look at the laws of reflection and refraction. We then delve into the formation of images through mirrors and lenses, examining focal points, focal length, and different types of images. Moving forward, we explore lens systems, including converging and diverging lenses, and learn how to use the thin lens equation for calculations. Finally, we discuss optical instruments like microscopes and telescopes, demonstrating their utilization of geometric optics to enhance human vision and magnify objects.