A dipole , with a dipole moment of magnitude p, is in stable equilibrium in an electrostatic field of magnitude E. Find the work done in rotating this dipole to its position of unstable equilibrium.

Explanation

The position of stable equi,ibrium corresponds to `theta=0^(@)`
The position of unstable equilibrium corresponds to `theta=180^(@)`.
The work done `=int_("theta=0^(@))^(theta=180^(@))pEsin thetad theta`
`=pE[-costheta]_(0^(@))^(180^(@))=2pE`