Igente Physics on Instagram: "Refractive Index — Explained Simply 🔍✨ The refractive index tells us how much light slows down and bends when it passes from one medium to another (like air → water → glass). What Is Refractive Index? Refractive index (symbol n) is defined as: n = speed of light in vacuum ÷ speed of light in a medium Light travels fastest in vacuum. When it enters a material, it slows down, and that change in speed causes the light to bend — this bending is called refraction. Why D