Question

Kerosene is known to float on the water but its refractive index is more than that of water. Arrange these two media in increasing order of
i) density ii) optical density

Answer 1

Answer:

i) Mass density:

ρ = m/V

We know that immiscible liquids create layers where the obj of less density floats over the obj of high density.

∴ Water, Kerosene.

ii) Optical density:

Optical density depends on the speed of light while it passes through the obj. When speed is higher, it is optically rarer medum & that of slower, optically denser medium.

∴ Kerosene, Water.

More:

• The find out the focal length, image formed, obj distance in a lens, we use: 1/v - 1/u = 1/f. (Reference point : pole.) — Gauss proved.
• But, if considered from focus, - f² = x1x2, where x1 = obj distance from focus, x2 = image distance from focus. (Refernce point : focus.) — Newton proved.
• Optical density of obj increases with temp. (Due to change in density.)