Questions and Answers
Touch the ends of the galvanometer wire to the positive and negative ends of the D battery. What happens to the needle in your galvanometer? What caused this?
When students touch the ends of the galvanometer wire to the terminals on the D battery, they should notice that the needle turns in one direction. This is caused by the direct current from the battery.
Is the current produced by the battery AC or DC?
The current is produced by direct current (DC); the needle moved in one direction only, just as DC current flows in one direction.
When you move the stack of magnets back and forth over the nail, what happens to the needle in your galvanometer? What can you conclude from this?
When the magnets are moved back and forth over the nail, the needle should move in one direction and then the other. Students should be able to conclude that the current is flowing in one direction and then the other when they move the magnet back and forth over the coils.
Did you produce AC current or DC current when you moved the magnet back and forth over the coils?
The fact that the current is flowing in one direction and then the other means the current produced is alternating current (AC).
What do you think would happen if you used a stronger magnet? More magnets? More coils of wire?
A stronger magnet or more magnets would make the needle swing farther or faster. So would more coils of wire around the nail.