Name the process associated with the following:
$(a)$ Dry ice is kept at room temperature and at one atmospheric pressure.
$(b)$ $A$ drop of ink placed on the surface of water contained in a glass spreads throughout the water.
$(c)$ $A$ potassium permanganate crystal is in a beaker and water is poured into the beaker with stirring.
$(d)$ An acetone bottle is left open and the bottle becomes empty.
$(e)$ Milk is churned to separate cream from it.
$(f)$ Settling of sand when a mixture of sand and water is left undisturbed for some time.
$(g)$ $A$ fine beam of light entering through a small hole in a dark room illuminates the particles in its path.

(N/A) Sublimation: Dry ice ($CO_2$ in solid state) directly converts into gas at room temperature.
$(b)$ Diffusion: The intermixing of particles of ink with water particles.
$(c)$ Dissolution/Diffusion: The solute (potassium permanganate) dissolves and spreads throughout the solvent.
$(d)$ Evaporation: Acetone has a low boiling point and turns into vapor at room temperature.
$(e)$ Centrifugation: The process of separating denser particles from lighter particles by spinning.
$(f)$ Sedimentation: The process where heavier insoluble particles settle down at the bottom due to gravity.
$(g)$ Scattering of light (Tyndall effect): The phenomenon where light is scattered by colloidal particles.