A light pipe known as optical fibre used to facilitate visual examination of internal organs is based on:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → total internal reflection
An optical fibre has a core of higher refractive index surrounded by a cladding of lower refractive index. Light sent in at one end meets the core-cladding boundary at an angle larger than the critical angle, so it is totally internally reflected again and again along the fibre, even when the fibre is bent. Almost no light is lost, and a bundle of such fibres carries the image from inside the body to the observer.
NCERT (2026-27):
Total Internal Reflection in Nature and Its Technological Applications – “… Obviously, optical fibres can also be used for transmission of optical signals. For example, these are used as a ‘light pipe’ to facilitate visual examination of internal organs like esophagus, stomach and intestines.”