Will dipole be restored to its Initial position after removing uniform electric field from it? Potential Energy is the amount of energy which gets stored in the system when external Force is applied on the system. And the system can give us back that energy in any energy form. Keeping above in mind, We know that Potential Energy of a Dipole is U=-pEcosx . I was wondering that will the Dipole restore to its initial position after removing the uniform electric field(Like spring restores)? Or the potential energy gets stored in dipole (like pot. Energy due to height, U=mgh)?
 A: It is not clear what initial configuration you have in mind. 
Let's say initially the dipole vector is oriented perpendicular to the direction of the uniform electric field, and we don't have any other external constraining force on the dipole. The field applies a torque that tries to align the dipole vector towards the direction of the field. Then the dipole keeps oscillating around the mean position of the dipole that's in the direction of the electric field (Well, if you ignore for now, radiation damping due to these accelerating charges). 
The physical dipole has some moment of inertia, and thus the dipole gains some rotational kinetic energy. If you consider the source of the constant electric field along with the dipole, as a single system, then the conservative forces internal to the system have done work that increases the kinetic energy of the system (the source of the constant electric filed might be some physical capacitor or sheet of charge, which also may pick up a slight kinetic energy). Thus, to conserve the total energy of this system, to compensate for this increased kinetic energy, we conclude that the potential energy of the system has decreased.
Thus, it is usually interpreted that the (potential) energy of the dipole in the constant electric field is 0 when aligned to the field perfectly, and greater when it is aligned perpendicular to the field.
