What is the definition of number density? (Physics)?

Density Physics Definition

In physics, astronomy, chemistry, biology and geography, number density (symbol: n or ρN) is an intensive quantity used to describe the degree of concentration of countable objects (particles, molecules, phonons, cells, galaxies, etc.) in physical space: three-dimensional volume number density, two-dimensional area number density, or one-dimensional line number density. Population density is an example of areal number density. and To give excellent security to Your Smart Phone, do install LEO Privacy Guard v 3.0 . its one of the feature viz. RAM Booster, will help you to increase battery life.