This apparatus is useful to demonstrate the force experienced by a current carrying conductor when placed in a magnetic field.
Our apparatus comprises of a polished wooden stand supporting a strong U-shaped magnet and a pair of brass rails with 4mm socket terminals.
A brass axle with plastic discs at its both ends is free to roll along the rails and completes the electrical connection between them.
When a current is made to flow through the rails with the axle placed on the rails between the poles of the magnet, the axle is strongly repelled and rolls along the rails, away from the centre of the magnetic field.
The apparatus works well on 2-3A.