Question

which of the two media has a higher optical density ?

Answer 1

Optical density is just a measure of how fast or how slow light propogates through a medium with respect to initial one.

The more optically dense a material,the slower light travels through it. It can be calculated by taking the ratio of the refractive indices of the two media.

OPTICAL DENSITY IS NOWHERE RELATED TO MASS DENSITY. This is a common misconception as one might observe that :

Density of vacuum<air<water<glass

And the speed of light decreases as it moves from one material to another, but there are many exceptions to this such as ETHANOL and WATER

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