$A$ light wave travels through three transparent materials of equal thickness. Rank in order,from the highest to lowest,the indices of refraction $n_1, n_2$ and $n_3$.

$A$ mark at the bottom of a liquid appears to rise by $0.1 \ m$. The depth of the liquid is $1 \ m$. The refractive index of the liquid is

When a light ray enters from air into water, which of the following properties does not change?

The refractive index of water is $1.33$. What will be the speed of light in water?

The refractive indices of water and glass with respect to air are $1.2$ and $1.5$ respectively. The refractive index of glass with respect to water is

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.
Assertion $(A)$: Refractive index of glass is higher than that of air.
Reason $(R)$: Optical density of a medium is directly proportionate 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.