Critical angle: Learn what critical angle is

Learn what critical angle is, how to calculate it, and why it is important for total internal reflection. Find out the critical angle values for different pairs of media and their applications in physics and chemistry. critical angle, in optics, the greatest angle at which a ray of light, travelling in one transparent medium, can strike the boundary between that medium and a second of lower refractive index without being totally reflected within the first medium. (The refractive index of a transparent substance is the ratio of the speed of light in a vacuum to its speed in that substance.) For any angle of incidence smaller than the critical angle, and for any angle at all if the ray strikes the boundary ... The longer and more complete answer: To understand what a critical angle is and why it happens, it is most intuitive to visualize the wave itself. The critical angle can be explained through the context of light (an electromagnetic wave), but refraction and critical angles occur for all types of waves. The critical angle formula is a fundamental concept in optics. It enables us to calculate the critical angle, beyond which total internal reflection occurs.