A dipole is placed in an electric field as shown. In which direction will it move ?

Answer: 2. towards the right as its potential energy will decrease.

Key idea: in a non-uniform field a dipole feels a net force towards the stronger or weaker field depending on its orientation, and it moves so that its potential energy falls.

1. The field lines spread out to the right, so the field is stronger on the left and weaker on the right.
2. The dipole moment points from \(-q\) to \(+q\), that is to the left, opposite to \(\vec E\). Its energy is \(U=-\vec p\cdot\vec E=+pE\).
3. \(U\) is smaller where \(E\) is smaller, so the dipole moves to the right. Check with forces: \(+q\) is pushed right with \(qE_{left}\), \(-q\) is pushed left with the smaller \(qE_{right}\); the net force is to the right.

Option 2: towards the right as potential energy decreases.