Question

is refractive index always grater then 1 ?explain
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Answer 1

Answer:

the ratio

is always greater than 1 .

Explanation:

The index of refraction is defined as the ratio of the speed of light in vacuum to the speed of light in any medium. The speed of light always decreases when it goes from a lighter medium to a denser medium. As the density of medium is always greater than density of vacuum, so the ratio is always greater than 1 .