The refractive index of water with respect to air is _aμ_w and of glass with respect to air is _aμ_g. Express the refractive index of glass with respect to water.

The refractive index of water with respect to air is _aμ_w.

$_{\text{a}}\text{μ}_{\text{w}} = \dfrac{\text{Speed of light in air}}{\text {Speed of light in water}} \\[0.5em]$

The refractive index of glass with respect to air is _aμ_g.

$_{\text{a}}\text{μ}_{\text{g}} = \dfrac{\text{Speed of light in air}}{\text {Speed of light in glass}} \\[0.5em]$

So, the refractive index of glass with respect to water is given by

$_{\text{w}}\text{μ}_{\text{g}} = \dfrac{$a\mug}{a\muw} \\[1em]