Give definitions of linear,surface,and volume charge densities and write their $SI$ units.

(N/A) $1$. Linear Charge Density $(\lambda)$: It is defined as the charge per unit length of a conductor. $\lambda = \frac{dq}{dl}$. Its $SI$ unit is $C/m$.
$2$. Surface Charge Density $(\sigma)$: It is defined as the charge per unit surface area of a conductor. $\sigma = \frac{dq}{dA}$. Its $SI$ unit is $C/m^2$.
$3$. Volume Charge Density $(\rho)$: It is defined as the charge per unit volume of a conductor. $\rho = \frac{dq}{dV}$. Its $SI$ unit is $C/m^3$.