Question
How should a magnetic dipole be placed in a uniform magnetic field so that its potential energy is maximum?
✓
Answer
Its magnetic moment should be in opposite direction of $\overrightarrow{ m } \cdot \overrightarrow{ B }$
$\because$ In this condition, $\theta=180^{\circ}$ and $U =-m B \cos \theta$
$U =-m B \cos 180^{\circ}=-m B \times(-1)$
$U =m B$
$\because$ In this condition, $\theta=180^{\circ}$ and $U =-m B \cos \theta$
$U =-m B \cos 180^{\circ}=-m B \times(-1)$
$U =m B$
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