Question

speed of light in vacuum is _______​

Answer 1

Answer:

approximately 300,000 kilometers per second

Light travels at approximately 300,000 kilometers per second in a vacuum, which has a refractive index of 1.0, but it slows down to 225,000 kilometers per second in water (refractive index of 1.3; see Figure 2) and 200,000 kilometers per second in glass (refractive index of 1.5).

Explanation:

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