On what factor does the lateral shift produced by a glass slab depend?

The velocity of light in a vacuum is $....$

The following table gives the values of refractive indices of a few media:

$S.No.$	$1$	$2$	$3$	$4$	$5$
Medium	Water	Crown glass	Rock salt	Ruby	Diamond
Refractive index	$1.33$	$1.52$	$1.54$	$1.71$	$2.42$

Use this table to give an example of $(i)$ a medium pair so that light speeds up when it goes from one of these media to another. $(ii)$ a medium pair so that light slows down when it goes from one of these media to another.

The absolute refractive indices of water,glass,and diamond are $1.33$,$1.50$,and $2.42$ respectively. Which medium is the most optically dense?

What are the units of refractive index?

When a light ray travels from an optically denser medium to an optically rarer medium, what is the angle of incidence called at which the angle of refraction becomes $90^{\circ}$?