When a drop of oil is spread on a water surface, it displays beautiful colours in daylight because of

When a drop of water is dropped on oil surface, then

Oil spreads on a water , why it is so?

Why does oil spread over the surface of water?

Explain why oil spreads over the surface of water?

A : Thin films such as soap bubble or a thin layer of oil on water show beautiful colours when illuminated by sunlight. R : The colours are obtained by dispersion of light only.