Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
**Assertion (A):** The refractive index of glass is higher than that of air.
**Reason (R):** The optical density of a medium is directly proportional to its mass density, which results in a proportionate refractive index.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer: (C) (A) is correct but (R) is not correct
Glass (about 1.5) does have a higher refractive index than air (about 1.0003), so A is correct.
Optical density (refractive index) is not proportional to mass density; for example, turpentine is optically denser than water though it is lighter. R is wrong.
Solution by Sreeraj P, M.Sc Physics