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Question
Why do diamonds sparkle?
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Solution
Critical angle for diamond is quite less and is only 24°. Besides these diamonds are cut very sharp, making a large number of the refracting surfaces. Hence when a ray of light enters a diamond, it suffers a series of total internal reflections on account of a very small critical angle. This makes a ray of light literally trapped within the diamond for a little time and this trapped light energy makes a diamond sparkle.
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