A point-like charge Q and a dipole with an electric moment Pel are separated by a distance that is considerably larger than the arm of the dipole, with the result that the dipole may be considered as being point. The dipole's axis lies :'along the lines of force 'of the point charge. Compare the force acting on the di pole ill the field of the point charge with t.hat acting on the point charge ill the Held of the di pole.