Final answer:
Total internal reflection occurs when light passes from a medium with a higher index of refraction to a medium with a lower one, and when the incident angle is greater than the critical angle. This principle is utilized in fiber optics and medical endoscopes.
Step-by-step explanation:
To create total internal reflection, light must pass from a medium with a higher index of refraction to a medium with a lower index of refraction. Moreover, the incident angle of the light in the first medium must be greater than the critical angle. This is the minimum angle of incidence at which light is totally internally reflected within a medium, rather than refracted out of it.
Fiber optics technology takes advantage of total internal reflection by transmitting light through fibers of plastic or glass, which act as light pipes. These optical fibers have a higher index of refraction than their surroundings, usually achieved by using cladding, a material with a lower refractive index that surrounds the fibers and ensures light does not escape through transmission to adjacent fibers.
Understanding and applying the principle of total internal reflection is not only crucial in fiber optics but also in the design of devices like endoscopes, which allow for internal examination of the body without invasive surgery.