Question

The S.I. unit of surface charge density is……….

• A. $Cc{m}^{-2}$
• B. $A{m}^{-2}$
• C. $Ac{m}^{-2}$
• D. $C{m}^{-2}$

Answer 1

The correct option is D

$C{m}^{-2}$

Explanation for correct option- (d)

1. Surface charge density is the quantity of charge per unit area.
2. Surface charge density $\left(\sigma \right)=\frac{q}{A}$, $q=$quantity of charge and $A=$area.
3. The S.I. unit of surface charge density is $C{m}^{-2}$ because the S.I. unit of charge is coulomb and the area is meter square.

Explanation for wrong options

(a)-$Cc{m}^{-2}$ is the unit of electric charge density, not an SI unit.

(b)-$A{m}^{-2}$ is the S.I. unit of electric current density.

(c)-$Ac{m}^{-2}$ is the unit of electric current density.

Hence, the correct option is (D).