Jharkhand PSC Prelim Exam 2010 Solved Paper

(4) Endoscopy is a nonsurgical procedure used to examine a person’s digestive tract. Using an endoscope, a flexible tube with a light and camera attached to it, your doctor can view pictures of your digestive tract on a color TV monitor.
Total internal reflection is the phenomenon which occurs when a propagated wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface.
Total internal reflection is the operating principle of optical fibers, which are used in endoscopes and telecommunications.