Two charges + q and -q are placed at a distance a in a uniform electric field. The dipole moment of the combination is $2\mathrm{qa} \left(\cos \mathrm{\theta } \hat{\mathrm{i}} + \sin \mathrm{\theta } \hat{\mathrm{j}}\right)$, where, θ 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 ?

• The torque exerted by the field on the dipole vanishes

• The net force on the dipole vanishes

• The torque is independent of the choice of coordinates

• The net force is independent of a