Potential Energy of Dipole in a Uniform Electric Field

Potential Energy of Dipole in a Uniform Electric Field

The work done in rotating  the dipole  from one orientation to another is stored in the form of energy called potential energy of dipole.

It is a scalar quantity.S.I. unit of potential energy is joule (J).

Work done to rotate the dipole electric field through an angle dθ against the torque is,

dW = τ dθ = pE sinθ dθ

Suppose, the dipole is rotated from orientation θ1 to θ2, then the total work done is given by,

daum_equation_1434535635126.png
If dipole is initially at right angle to daum_equation_1434533781413.png i.e., θ1 = 90° and finally it makes an angle θ with i.e., θ2 = θ, then

W = – pE (cosθ – cos 90°)
W = – pE cosθ

This work done is equal to the potential energy U of the dipole.

daum_equation_1434535920402.png

Cases:

daum_equation_1434533476268.png

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