Chapter 22, Problem 7Q

The potential energies associated with four orientations of an electric dipole in an electric field are (1) −5 U₀, (2) −7 U₀, (3) 3 U₀, and (4) 5 U₀, where U₀ positive. Rank the orientations according to (a) the angle between the electric dipole moment $\stackrel{\to }{p}$ and the electric field $\stackrel{\to }{E}$ and (b) the magnitude of the torque on the electric dipole, greatest first.