An electric dipole is held in a uniform electric field.
The dipole is aligned parallel to the field. Find the work done in rotating it through the angle of `180^(@)`.

Explanation

Work done in rotating the dipole through an angle `d theta` is `pE sin theta d theta`.
where, p = dipole moment,
E = magnitude of the field
`:.` Work done in rotating the dipole from `0^(@)` parallel to the field) to `180^(@)`
`= int_(0^@)^(180^@) pE sin theta d theta = pE (- cos theta)_(0)^(180^@) = 2 pE`.