<Li> Diamonds shine brightly due to total internal reflection . </Li> <Li> Total internal reflection (TIR) are used on lighting industry to manage narrow distribution (NEMA classification) for floodlight . </Li> <P> Total internal reflection can be observed while swimming, when one opens one's eyes just under the water's surface . If the water is calm, its surface appears mirror - like . Diamonds used for jewelry are normally shaped in such a way as to maximize the amount of light that is totally internally reflected from the back side of the diamond . The very high refractive index of diamond gives a small critical angle allowing almost all the light entering the diamond to be reflected back for optimized diamond cuts such as the brilliant . </P>

When does total internal reflection occur in water
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