Lecture Demonstrations
Lecture Demonstrations

Electricity and Magnetism

Electromagnetic Induction

Eddy currents: Juming rings

Used to illustrate that the induced EMF depends on the conductivity of the object. In other words, it depends on the material and the shape.

APPARATUS:
LOCATION:
     Ring launcher
O1
     Rings
O1
     Lamp
O1


Place different types of rings on the ring launcher. Watch how high each ring jumps. If you put rings in liquid nitrogen, the conductivity increases and it jumps higher. Also, show that the lamp lights up due to the induced current in the wire.

 

photo: eddy current