Question

The following table gives the refractive indices of a few media : $\begin{array}{cccccc}& 1& 2& 3& 4& 5\\ Medium:& Water& Crownglass& Rocksalt& Ruby& Diamond\\ Refreactiveindex:& 1.33& 1.52& 1.54& 1.71& 2.42\end{array}$

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

Answer 1

1)-light speeds up when it goes from denser to rarer medium
so $v=\frac{c}{n}$
light speeds up when it goes from crown glass to water.

2)-light slows down when it goes from rarer medium to densor medium.
light slows down when it goes from water to crown glass or ruby or diamond.