Module 3 : MAGNETIC FIELD
Lecture 14 : Potential Energy of a Magnetic Dipole
 

The work done is given by

\begin{eqnarray*} W &=& \int_0^\theta\tau d\theta\\ &=& \int_0^\theta \mu B\si... ...heta\\ &=& -\mu B\cos\theta\mid_0^\theta = (1-\cos\theta)\mu B \end{eqnarray*}

This amount of work is stored as the additional potential energy of the dipole. In analogy with the case of electric dipole in an electric field, the potential energy of the magnetic dipole in a magnetic field is given by

\begin{displaymath}U= -\vec\mu\cdot\vec B= -\mu B\cos\theta\end{displaymath}

The energy is lowest when $\vec\mu$and $\vec B$are along the same direction and is maximum when they are anti-parallel.
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