Dipole Moment Practice Problems
An electric dipole is an assembly of two equal opposite charges separated by a distance d. When placed in an electric field, the dipole has one stable orientation and the torque on that dipole for that orientation is zero. Does the dipole's electric field point in the same direction as the external electric field or oppose it?
Alignments that offer zero torque when a dipole lies in an even external electric field are classified as stable and unstable. Identify the stable and unstable alignments. Hint: What is the effect of a slight rotation for an equilibrium alignment?
Two tiny charged spheres charged to +q = +3.2 nC and -q = -3.2 nC are connected using a 4.2 mm long non-conducting rod to form an electric dipole. The arrangement is placed in a uniform electric field. The angle made by the electric field and the connecting rod is 40°. If the torque on the dipole is 6.3 × 10-9 N•m, determine the magnitude of the electric field. Treat the tiny spheres like point charges.
A group of students construct an electric dipole using two small charged spheres. The dipole is placed in a region where the electric field is uniform. What alignments create zero torque on the dipole?