Why do fiber optic cables transmit light?

Answer: Internal reflection traps light

Cables eliminate light scattering — Wrong. High-quality glass reduces scattering, but transmission works through total internal reflection keeping light trapped inside the fiber.

Straight path guides photons — Wrong. Fiber optics can bend! They work through total internal reflection—light hits the glass-cladding boundary at shallow angles, reflecting back internally.

Internal reflection traps light ✓ — Correct! Fiber optics use total internal reflection. Light enters the glass core at specific angles. When it hits the core-cladding boundary, the angle is shallow enough that light reflects completely (no refraction out). Light bounces through the fiber, even around bends, carrying data at light speed. Used in internet, medicine, and telecommunications!