What is the relation between refractive index of glass with respect to air and refractive index of air with respect to glass?

(i) What is the relation between the refractive index of water with respect to air `("_aμ_\text(w))` and the refractive index of air with respect to water `("_\text(w)μ_ a)` .
(ii) If the refractive index of water with respect to air `("_aμ_\text(w))` is`5/3`. Calculate the refractive index of air with respect to water `("_\text(w)μ_ a)` . 

(i)  `"_a μ_\text(w) =(mu_\text(w))/(mu_a)`

    ` "_\text(w) μ_a   = (mu_a)/(mu_\text(w) `

     `∴ "_a μ_\text(w) `= `1/ ("_\text(w) mu_a)`

(ii)  ` "_a μ_\text(w) = 5/ 3`

      ` "_\text(w) mu _a = 3/5 `

Concept: Refraction of Light Through a Rectangular Glass Slab

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