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The light traveling a 3 lake km/sec, but Pls tell me how can a control the speed of light, means can limit the speed like 2 lake km/sec are 1 lake km/sec

Pls tell me equation

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closed as unclear what you're asking by Chris White, Manishearth Jul 23 '13 at 6:40

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

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Dear Anil, I'm having troubles reading your question. Can you make it, somewhat more readable? –  Ali Jul 23 '13 at 6:07

1 Answer 1

Speed of light $c$ in medium is reduced by its refractive index $n$.

$$c=\frac{c_0}{n}$$ where $c_0 = 299\,792\,458\frac{m}{s}$ is speed of light in vacuum. You are asking for a material of refractive index $n=1,5$ which is e.g. the glass BK-7.

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