Two charges `+q and-q` are placed at a distance a in a uniform electric field. The dipole moment of the combination is `2aq(cos theta hati+ sin theta hatj)`, where `theta` is the angle between the direction of the field and the line joining the two charges. which of the following statement (s) is/are correct ?

Options

A. the torque exerted by the field on the dipole vanishes
B. the net force on the dipole vanishes
C. the torque is independent of the choice of coordinates
D. the net force is independent of a

Explanation

The resultant force applied on a dipole in a uniform electric field, but the moment of force or torque cannot be zero.
Torque, `vec tau= vecpxx vecE[ vecp`= dipole moment, `vecE`= electric field.]
This vector relation is independent of the choise of the coordinate system.
Again, since the resultant forc is zero, hence it is independent of a.
The option (B),(C) and (D) is correct.