Question

for an electric dipole in an external electric field,relate potential energy of the dipole to the work done by a torque as the dipole rotates in the electric field? ​

Answer 1

Answer:

the force experienced by charges is given by qE along the electric field by the positive charge

and qE opposite to the direction of electric field by the negative charge.

We know that torque on a dipole is

= P(dipole moment vector) × E (electric field vector)

the amount of work done by torque is

( see the attachment)

Now ,

as we know that the workdone in bringing a system of charges from infinity to the given configuration is defined as the potential energy of the system

the potential energy (U) is given by

U = W = PE(cos(theta 1) - cos(theta 2) )