Physics Demo Number: 211
Approximate Run Time: 5 min
Magnetic forces on a wire carrying DC and AC currents
Demo Description
The toggle switch on the device can be set to send either AC or DC current through the specially shaped filament in the light bulb.One can bring a magnet near the filament and observe its behavior in each case.
The vibration in the filament (in the AC case) can cause it to break, so its probably best not to bring the magnet too close to it.
Scientific Principles
Lorentz force, AC and DC currents.Equipment
- Device consisting of a lightbulb with a looped filament, and a toggle switch that allows one to send either AC or DC through it.
- Magnet
Equipment Location
- The apparatus is in [B-2-5]
- Magnets are in [A-2-1]
Instructions
The figure shows the apparatus, together with a neodynium magnet.