Fiber optic cables carry telephone, internet and cable TV signals by relying on which optical effect inside thin fibers of glass or plastic?

1. Fiber optics transmit telephone, internet and cable TV signals by sending light down thin fibers of plastic or glass. 2. Because the fibers are thin, entering light is likely to strike the inside surface at an angle greater than the critical angle and is totally reflected. 3. The index of refraction outside the fiber must be smaller than inside for this total internal reflection to keep happening. 4. Dispersion and polarisation are not the mechanism keeping the signal confined inside the fiber as it travels and bends. _Source: OpenStax Physics (CC BY 4.0), Ch 16 "Mirrors and Lenses", section 16.2 Refraction_