Magnetic Torque on a Current Loop

Discover how magnetic fields exert torque on current-carrying loops, leading to rotational motion. Click and drag the loop to rotate it!

Magnetic Dipole Moment ($ \vec{\mu} = NIA\hat{n} $)

A current loop creates its own magnetic field, behaving like a tiny magnet. Its strength and orientation are described by the magnetic dipole moment ($\vec{\mu}$), which depends on the current ($I$), number of turns ($N$), and area ($A$) of the loop, with direction perpendicular to the loop's plane ($\hat{n}$).

Torque ($ \vec{\tau} = \vec{\mu} \times \vec{B} $)

  • When a magnetic dipole is placed in an external magnetic field ($\vec{B}$), it experiences a torque ($\vec{\tau}$).
  • The torque tries to align the magnetic dipole moment ($\vec{\mu}$) with the external magnetic field ($\vec{B}$).
  • The magnitude of the torque is $ \tau = \mu B \sin\theta $, where $\theta$ is the angle between $\vec{\mu}$ and $\vec{B}$.

What's Happening?

Torque & Alignment

Loop & Field Controls