Refractive indices of water, sulphuric acid, glass and carbon disulphide are 1.33, 1.43, 1.53 and 1.63 respectively. The light travels slowest in:

The refractive index of water is:

The refractive index of water with respect to air is 4/3. The refractive index of air with respect to water will be:

The refractive index of glass with respect to air is 3/2 and the refractive index of water with respect to air is 4/3. The refractive index of glass with respect to water will be

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

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.

(ii) A medium pair so that light slows down when it goes from one of these medium to another.