WEBVTT
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The refractive index of crown glass is 1.52.
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What is the speed of light in crown glass?
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In our solution, we can refer to the refractive index of crown glass, 1.52, as π sub π.
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We want to know the speed of light in crown glass, which weβll call π£.
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And in this problem, weβll assume that the speed of light, π, is exactly 3.00 times 10 to the eighth meters per second.
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Letβs start by recalling the mathematical relationship defining index of refraction.
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A materialβs refractive index, π, is defined as the speed of light in vacuum, π, divided by the speed of light in that material.
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When we apply this relationship to our situation, we see the refractive index of crown glass, π sub π, equals π divided by π£, the speed of light in crown glass.
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Rearranging this equation to solve for π£, we see that itβs equal to π over π sub π.
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When we plug-in for these two values and calculate this fraction, we find that π£ equals 1.97 times 10 to the eighth meters per second.
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Thatβs the speed of light in crown glass, roughly two-thirds the speed of light in vacuum.