If the absolute refractive indices of glass and water are 3/2 and 4/3 respectively, what is the refractive index of glass with respect to water?

Assume, Refractive index (n) = c (velocity of light in vacuum) / v (velocity of light in a medium)

Then, 4/3 = c/ v₁ (velocity of light in water) and 3/ 2 = c/ v₂(velocity of light in glass)

Now, velocity of light in water / velocity of light in glass = (c/ v₁) / (c/ v₂) = (4/3) / (3/2)

We get v₂ / v₁ = 8/9

Thus, v₁ / v₂= 9/8

So, 9/8 is the refractive index of glass with respect to water.