Total Internal ReflectionTotal Internal Reflection

Dense SourceDense Source Rays starting in a denser Rays starting in a denser

medium will refract away from medium will refract away from normal in the less dense normal in the less dense medium.medium.

Critical AngleCritical Angle At the critical angle the At the critical angle the

refraction is 90refraction is 90°°..

All the light is internally All the light is internally reflected.reflected.

RaindropRaindrop

A raindrop exhibits both reflection and dispersion.A raindrop exhibits both reflection and dispersion.

RainbowRainbow

Double RainbowDouble Rainbow The secondary rainbow is The secondary rainbow is

fainter than the primary.fainter than the primary.

The secondary rainbow arises The secondary rainbow arises from light that makes two from light that makes two reflections from the interior reflections from the interior surface before exiting the surface before exiting the raindrop.raindrop.

Higher-order rainbows are Higher-order rainbows are possible, but their intensity is possible, but their intensity is low.low.

Fiber OpticsFiber Optics Plastic or glass rods are used Plastic or glass rods are used

to “pipe” light from one place to to “pipe” light from one place to another.another.• Medical use for diagnosis and Medical use for diagnosis and

correction of medical problemscorrection of medical problems• TelecommunicationsTelecommunications• DecorationDecoration

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