Refractive index of glass with respect to water is `(9//8)`.
Refractive index of glass with respect to air is `(3//2)`. find the refractive index of water with respect to air .

Explanation

Given, `""_(w)mu_(g)=9/8 and ""_(a)mu_(g)=3//2`
`As, ""_(a)mu_(g)xx""_(g)mu_(w)xx""_(w)mu_(a)=1`
`therefore 1/""_(w)mu_(a)=""_(a)mu_(w)=""_(a)_mu_(g)xx""_(g)mu_(w)=(""_(a)mu_(g))/(""_(a)mu_(g))`
`therefore` Refractive index of water with respect to air,
`""_(a)mu_(w)=(3//2)/(9//8)=4/3`