Question

The vector form of the torque on a magnetic dipole in a uniform magnetic field is:

Options

• \[\vec{\tau} = \vec{B} \times \vec{m}\]

• \[\vec{\tau} = mB\cos\theta\]

• \[\vec{\tau} = \vec{m} \cdot \vec{B}\]

• \[\vec{\tau} = \vec{m} \times \vec{B}\]

Answer 1

The torque on a magnetic dipole is the cross product \[\vec{\tau} = \vec{m} \times \vec{B}\], where \[\vec{m} = NI\vec{A}\]. Its magnitude is \[mB\sin\theta = NIAB\sin\theta\], matching the scalar expression for the torque.