Question

refractive index of glass is 1.5what is meant by this statement
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Answer 1

Explanation:

For this you should know what is relative index..

1. That is..-: speed of light in the medium from which light travels / speed of light in the medium into which light travels .
2. So the relative index of glass is 1.5 to 1.7 ..

Answer 2

Light travels 1.5 times slower in glass than in vacuum.

The refractive index is the ratio of the speed of glass in a particular medium and the speed of glass is vacuum. Thus it tells by how much light slows down in a particular medium