Electrostatics

An electrostatic field line cannot be discontinuous.
Why ? [AI 2005]

Two electric field lines never cross each other.
Why ? [AI 2005]

The distance of the field point, on the equatorial
plane of a small electric dipole, is halved. By
what factor will the electric field, due to the
dipole, change ? [Delhi 2004C]

Write the condition under which the potential
difference between the terminals of a battery
and its emf is equal.

Two charges ql and qy separated by a small
distance, satisfy the equation ql + q2 = 0. What
does it tell us about the charges ?
[Foreign 2003]

Two point charges q1 and q2 are placed close
to each other. What is the nature of force
between the charges when ql q2< 0 ?
[Foreign 2003]