24. Electric Force & Field; Gauss' Law

Torque on a Dipole. An electric dipole with dipole moment p is in a uniform external electric field E. (c) Show that for the stable orientation in part (b), the dipole's own electric field tends to oppose the external field.

Torque on a Dipole. An electric dipole with dipole moment p is in a uniform external electric field E. (b) Which of the orientations in part (a) is stable, and which is unstable? (Hint: Consider a small rotation away from the equilibrium position and see what happens.)

Torque on a Dipole. An electric dipole with dipole moment p is in a uniform external electric field E. (a) Find the orientations of the dipole for which the torque on the dipole is zero.

Point charges q1 = -4.5 nC and q2 = +4.5 nC are separated by 3.1 mm, forming an electric dipole. (b) The charges are in a uniform electric field whose direction makes an angle of 36.9° with the line connecting the charges. What is the magnitude of this field if the torque exerted on the dipole has magnitude 7.2 * 10^-9 N•m?