If the electric flux entering and leaving an enclosed surface is $\phi_1$ and $\phi_2$ respectively, then the charge enclosed in the surface is ($\varepsilon_0 =$ permittivity of free space).

Select the correct statement$(s)$.
$(1)$ The tangent drawn at any point on an electric field line gives the direction of the force acting on a positive charge at that point.
$(2)$ The normal drawn at any point on an electric field line gives the direction of the force acting on a positive charge at that point.
$(3)$ Electric field lines start from a negative charge and end on a positive charge.
$(4)$ Electric field lines start from a positive charge and end on a negative charge.

Assertion : Electric lines of force never cross each other.
Reason : Electric field at a point superimpose to give one resultant electric field.

$A$ charge $q$ is placed at the center of one of the faces of a cube. What is the electric flux linked with the cube?

An electric dipole is placed in the north-south direction inside a sphere filled with water. Which statement is correct?

$A$ charge is uniformly distributed on the surface of a spherical rubber balloon. As it is blown up,the total electric flux coming out of the surface