Question

What is the final formula for the potential energy of a dipole in a uniform electric field?

Options

• \[U = \frac{pE}{\cos \theta}\]

• \[U = -\mathbf{p} \cdot \mathbf{E} = -pE \cos \theta\]

• \[U = pE \sin \theta\]

• \[U = pE \cos \theta\]

Answer 1

The potential energy of a dipole in a uniform electric field is given by \[U = -\mathbf{p} \cdot \mathbf{E}\], which in scalar form is \[U = -pE \cos \theta\]. The negative sign indicates that the dipole has minimum potential energy when aligned with the field (θ = 0°).