When light travels through a fiber-optic cable, the change in refractive index causes it to refract off which boundary?

In fiber optics, light travels through a core that has a higher refractive index compared to the surrounding cladding. This difference in refractive index is crucial as it facilitates the phenomenon known as total internal reflection, which is the principle that allows light to be transmitted effectively through the fiber-optic cable.

When light reaches the boundary between the core and the cladding, if the angle of incidence is greater than the critical angle, the light will be refracted back into the core rather than passing into the cladding. This consistent bouncing of light within the core enables the fiber-optic cable to transmit signals over long distances with minimal loss.

The other scenarios do not directly involve the mechanism by which light is guided through the fiber. The boundary between air and glass does not play a role in the guiding of light within the fiber itself, as the main function takes place within the core and cladding. Similarly, boundaries between different cores or mechanical supports do not contribute to the fundamental optical guiding process in the fiber-optic system. Thus, the significance of the core and cladding boundary is highlighted as the location where light is refracted, making it the key to understanding fiber-optic technology.