An electric dipole of dipole moment `vecp` is placed in an electric field `vecE`such that `vecp` and `vecE` are parallel to each other. From this orientation electric dipole is turned through `180^@`. What will be the work done by an external agent?

Explanation

To find the work done by an external agent when an electric dipole is turned through 180 degrees in an electric field, we can follow these steps:

### Step 1: Understand the initial and final positions of the dipole
Initially, the dipole moment \(\vec{p}\) is aligned with the electric field \(\vec{E}\). After turning the dipole through \(180^\circ\), the dipole moment will be anti-parallel to the electric field.

### Step 2: Write the expression for the torque on the dipole
The torque \(\tau\) acting on an electric dipole in an electric field is given by:
\[
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