Endoscopy, a technique used to explore the stomach or other inner parts of the body is based on the phenomenon of

1. Endoscopy uses optical fibers to transmit light into the body and relay images back to the observer. 2. This transmission of light through optical fibers relies on the principle of total internal reflection. 3. When light traveling in a denser medium strikes the boundary with a less dense medium at an angle greater than the critical angle, it is completely reflected back into the denser medium. This phenomenon is total internal reflection. 4. Optical fibers are designed to guide light over long distances using repeated total internal reflections. 5. Interference, diffraction, and polarisation are other wave phenomena of light but are not the primary principle behind the image transmission in endoscopy.