Question

refractive index of different media are given (water,coconut oil,flint gas ,diamond,benzene,and hydrogen)in which velocity of light is more and in which less

Answer 1

You haven't given the refractive indices of the media.
Anyway, the highest refractive index is of diamond and hence velocity of light will be slowest in it.

the lowest refractive index is of hydrogen and hence velocity of light will be highest in it.

Answer 2

hi there,
as the refractive index increases the speed decreases, refractive index is more in diamond and the velocity of light is slowest.
in hydrogen the refractive index is less so the  velocity of light is highest  ..
i hope this helps u...