Explain volume charge density. Write its unit.

Hint: This question is based on the concept of distribution of charges across a body. Distribution of charges can be identified in the form of linear charge density, surface charge density or volume charge density. It depends upon the shape and size of the body in consideration.

Complete step by step answer:
Charge density is the amount of electric charge per unit length, surface area, or volume in electromagnetism.
The quantity of charge per unit area, measured in coulomb per square meter, at any point on a surface charge distribution on a two-dimensional surface is known as surface charge density (). The quantity of charge per unit length, measured in coulomb per meter, at any point on a line charge distribution is known as linear charge density. Since electric charge can be positive or negative, charge density can also be positive or negative.
The charge per unit volume is called volume charge density and is defined by when the charge density is distributed within the volume of a body. The symbol used for volume charge density is generally $\rho $.
$\rho = \dfrac{q}{V}$
Here $\rho $= Volume charge density
$q$= Total charge on the body
$V$= Total volume of the body
From the above formula, it is clear that SI unit of volume charge density is coulomb per cubic meter. ($C/{m^3}$)

Note: The definition of a continuous charge distribution is an approximation that becomes misleading at small length scales since all charge is borne by subatomic particles that can be idealized as points. In the end, a charge distribution is made up of individual charged particles separated by non-charged regions.