Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 108 m s−1.
Solution and Explanation
Refractive index of a medium nm is given by,
\(n_m = \frac{\text{Speed of light in vacuum}}{\text{Speed of light in the medium }}\)
\(=\frac{ c }{v}\)
Speed of light in vacuum, c = 3 × 108 m s−1
Refractive index of glass, ng = 1.50
Speed of light in the glass,
\(v=\frac{c}{n_g}\)
\(=\frac{3\times10^8}{1.50}\)
\(=2\times10^8\) ms-1
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