Electrostatic Potential and Capacitance Part 2

Concept:Series combination reduces effective capacitance; dielectrics allow polarization; capacitance depends on area and separation; spherical surfaces around a point charge are equipotential.Explanation:Statement A: For series combination, $\frac{1}{C_{\text{eff}}} = \frac{1}{C_1} + \frac{1}{C_2} + \cdots$.The reciprocal sum makes $C_{\text{eff}}$ smaller than the smallest individual capacitor.Thus statement A is correct.Statement B: Dielectrics do not conduct electricity, but they allow displacement of charges by polarization.Under an electric field, molecules align, causing a slight shift of positive and negative charges.Hence statement B is false.Statement C: For a parallel plate capacitor, $C = \frac{\kappa \epsilon_0 A}{d}$.Increasing area $A$ or decreasing thickness $d$ both increase capacitance.So statement C is correct.Statement D: Potential due to a point charge is $V = \frac{kq}{r}$, which depends only on distance $r$.All points at the same distance form a spherical shell, making it an equipotential surface.Thus statement D is correct.Answer:Statements A, C, D are correct; B is incorrect. Hence the correct option is A.