The incident angle that produces an angle of refraction of 90∘ is called critical angle. Total internal reflection is a phenomenon that occurs at the boundary between two mediums, such that...The incident angle that produces an angle of refraction of 90∘ is called critical angle. Total internal reflection is a phenomenon that occurs at the boundary between two mediums, such that if the incident angle in the first medium is greater than the critical angle, then all the light is reflected back into that medium. Fiber optics involves the transmission of light down fibers of plastic or glass, applying the principle of total internal reflection.
