Potential energy of an electric dipole rotated in an uniform electric field | class 12 physics | advguruji
Consider, an electric dipole having dipole moment p in an uniform electric field E such that the dipole moment is making an angle θ with the field. Now, small amount of work done dW in rotating the dipole by small angle dθ is - Total work done when dipole is rotated from angle θ1 to angle θ2 with the field is - = -pE[Cosθ2 - Cosθ1] W = pE[Cosθ1 - Cosθ2] This work done will be stored as potential energy of the dipole. Therefore, U = pE[Cosθ1 - Cosθ2] NOTE :- As we know, more the potential energy of a system, less it will be stable and vice versa. 1. For most stable condition [U = minimum] θ1 = 180° , θ2 = 0° Therefore, U = -2pE 2. For most unstable condition [U = maximum] θ1 = 0° , θ2 = 180° Therefore, U = pE[1 - (-1)] U = 2pE Still not clear click here to watch by www.advguruji.blogspot.com