Description: This demo shows that a moving magnetic field induces a current in a coil of wire, and that the direction of the moving magnetic field determines the direction of the induced current. Can be displayed on an overhead projector.
- Bar magnet
- 250 or 1000 turn coil
- Two long banana plug cables
- Magnetize the bar magnets with the electric magnetizer
- Connect the galvanometer to the wire coil
- Test to make sure the galvanometer has the appropriate sensitivity, if too sensitive use less turns, if not sensitive enough use more turns. (remember you can use the half turn tap on some coils)
- Place the galvanometer on the overhead projector and focus it
- Turn on the projector
- You may start by having the coil stationary and moving the magnet in and out of the coil
- Note that moving toward the coil makes the needle move one way, while moving away from the coil moves the needle in the opposite direction (This is analogous to Alternating Current)
- Show that the relative movement between the two is what induces a current by fixing the magnet and moving the coil back and forth
Note: The individual coils are more effective.
Make sure the coil has the appropriate number of turns to be in the range of the galvanometer