Assertion: Electrostatic force between two charges is a conservative force.

Reason: Electric force between two charges is inversely proportional to the square of distance between the two.

Assertion: Electric lines of force are normal to any equipotential surface at all points on the surface.

Reason: Electric field is strong at points where equipotential surfaces are crowded and vice-versa.

Assertion: On going away from a point charge or a small electric dipole, the electric field decreases at the same rate in both cases.

Reason: Electric field is inversely proportional to the square of the distance from the charge in all cases.

Assertion: The electrostatic potential is necessarily zero at a point, where the electric field strength is zero.

Reason: A charged particle in an electric field will move from higher potential region to lower potential region.

Assertion: In a given situation of arrangement of charges, an additional charge is placed outside the Gaussian surface. In the Gauss' theorem $\oint \overrightarrow{E}.d\overrightarrow{s}=\frac{Q_{\mathrm{in}}}{{\epsilon }_0},Q_{\mathrm{in}}$ remains unchanged whereas electric field $\overrightarrow{E}$ at the site of the element is changed.

Reason: Electric field at any point on the Gaussian surface is only due to inside charge.

Assertion: An electric charge is fixed in free space which produces an electric field around it. No work is done in displacing another charge from its position to any other position.

Reason: Electrostatic field is non conservative.

Assertion: Electric field lines do not cut at any point.

Reason: At any point, there is only one direction of electric field.

Assertion: Electrostatic field lines never form closed loops.

Reason: Electrostatic field is a conservative field.

Assertion: If a conductor is given a certain, charge then no excess inner charge appears. 

Reason: In electrostatic condition field inside a conductor is zero.