Current-carrying ladder swing in a magnetic field (schematic)

The ladder swing is a physical experiment in the field of electromagnetic induction .

## experiment

Animation of a ladder swing test, showing the Lorentz force on a current-carrying conductor.

A ladder swing consists of a horseshoe magnet , between whose poles a non-magnetizable, but conductive rod is attached, which is connected to a circuit .

As soon as the circuit is closed, which is often indicated by the glow of a lamp or an ammeter, the rod begins to move in one direction. This direction is determined by the three-finger rule , the cause of the movement is the Lorentz force .

If the rod is moved manually in the magnetic field, electrons will move in the rod due to the Lorentz force . When the circuit is open, they will - to put it clearly - collect at one end. The charge separation will end when the Lorentz force is in equilibrium with the electrical force , i.e. when applies, in other words . The result is the law of induction for the moving conductor. ${\ displaystyle F_ {L} = F_ {el}}$${\ displaystyle e \ cdot v \ cdot B = e \ cdot {\ frac {U} {l}}}$