Answer:
Water is denser medium and air is rare medium.
Step-by-step explanation:
Denser medium ( water ) has a higher absolute refractive index than that of the other compared medium ( air ).
Absolute refractive index = refractive index of a material relative to vacuum.
Denser medium is the medium which velocity is law when rays going through it and rare medium is a medium which velocity is higher when rays going through. there fore we can obtain by Snell's law bellow equation,
n1 / n2 = C1 / C2
And also we can define reflective index by this manner
1) Absolute reflective index
Absolute reflective index = Velocity in vacuum / Velocity in media
2) Relative refractive index = Velocity in 1st medium / Velocity in 2nd medium