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प्रश्न
The diagram shows the path of a ray of light through a rectangular glass block placed in a liquid of uniform density.
(a) Does the light speed up or slow down in the glass,
(b) Give the reason for your answer.
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उत्तर
(a) The speed of light, travelling from liquid to glass, slow down.
(b) Speed in liquids = `"Speed of light of air"/"Refractive index of liquid"=(3xx10^8)/"Refractive index of liquid"`
Speed of light in glass = `"Speed of light in air"/"Refractive index of glass"=(3xx10^8)/"Refractive index of glass"`
Since the refractive index in glass is usually higher than that of liquid, hence the speed of light in glass will be less.
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