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