A point $$P$$ lies at a distance $$x$$ from the mid point of an electric dipole on its axis. The electric potential at point $$\mathrm{P}$$ is proportional to

Beams of electrons and protons move parallel to each other in the same direction. They

Assertion (A) : Work done in moving a charge around a closed path, in an electric field is always zero.

Reason (R) : Electrostatic force is a conservative force.