The correct answer is (c) total internal reflection of light.
An endoscope is a medical instrument used to examine the inside of a body cavity. It consists of a long, flexible tube with a light source and a camera at the end. The tube is inserted into the body through a small incision, and the camera allows the doctor to see the inside of the body on a monitor.
Total internal reflection occurs when light passes from a medium with a higher refractive index to a medium with a lower refractive index, and the angle of incidence is greater than the critical angle. The critical angle is the angle of incidence at which all of the light is reflected back into the first medium.
In an endoscope, the light from the light source is passed through the flexible tube and into the body. The light then strikes the walls of the body cavity, and some of the light is reflected back into the tube. The reflected light is then captured by the camera and displayed on a monitor.
Total internal reflection is used in endoscopes because it allows the doctor to see a clear image of the inside of the body. The light is reflected back into the tube at a very sharp angle, which prevents it from scattering and causing glare. This results in a clear, high-quality image.
The other options are incorrect because they do not explain how an endoscope works.
(a) Reflection of light occurs when light hits a surface and bounces off. This is not how an endoscope works.
(b) Dispersion of light occurs when light passes through a medium and is separated into its different colors. This is not how an endoscope works.
(d) Refraction of light occurs when light passes from one medium to another and bends. This is not how an endoscope works.