$\huge \frac{\sin\theta_{1}}{\sin \theta_{2}} = \frac{c_{1}}{c_{2}} = \frac{\eta_{1}}{\eta_{2}} $ A law governing how a [[Wave]] will [[Refraction|refract]] when switching from one medium to another. For some [[Ray]] of [[Electromagnetic Radiation|Light]] traveling from one medium with an [[Index of Refraction]] $\eta_{1}$ that is at a angle of $\theta_{1}$ from the vertical, the ray of light entering the next medium with [[Index of Refraction]] $\eta_{2}$ will [[Refraction|refract]] and have a new angle of $\theta_{2}$ from the vertical. ![[Snell's Law .excalidraw.svg]] %%[[Snell's Law .excalidraw.md|🖋 Edit in Excalidraw]]%%