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Question
The refractive index of glass is 1.5. What is the speed of light in glass? (Speed of light in vacuum is 3.0 × 108 m s−1)
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Solution
Refractive index of glass, μ = 1.5
Speed of light, c = 3 × 108 m/s
Speed of light in glass is given by the relation,
v = `c/μ`
= `(3 xx 10^8)/1.5`
= 2 × 108 m/s
Hence, the speed of light in glass is 2 × 108 m/s.
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