Linear charge density $(\lambda):$ The amount of charge per unit length is called linear charge density $(\lambda)$. $\lambda = \frac{Q}{l}$,where $Q$ is the total charge and $l$ is the length.
Unit: $C/m$. Dimensional formula: $[M^0 L^{-1} T^1 A^1]$.
Surface charge density $(\sigma):$ The amount of charge per unit area is called surface charge density $(\sigma)$. $\sigma = \frac{Q}{A}$,where $Q$ is the total charge and $A$ is the area.
Unit: $C/m^2$. Dimensional formula: $[M^0 L^{-2} T^1 A^1]$.
Volume charge density $(\rho):$ The amount of charge per unit volume is called volume charge density $(\rho)$. $\rho = \frac{Q}{V}$,where $Q$ is the total charge and $V$ is the volume.
Unit: $C/m^3$. Dimensional formula: $[M^0 L^{-3} T^1 A^1]$.