Coil Battery Magnet

In the picture

1. 1Few copper turns around the left iron nail
2. 2One battery wired to the left coil
3. 3Dense copper turns around the right iron nail
4. 4Three stacked batteries wired to the right coil
5. 5Bare iron nail with two tacks beside it and no wire connected

Examples

• Doorbells use an electromagnet to hit a chime.
• Scrapyard cranes use electromagnets to lift and drop metal.

Quiz: Coil Battery Magnet (Age 13)

1. 1

   What happens when electric current flows through a coil of wire wrapped around an iron nail?

   • The nail becomes a magnet that can be switched on and off.
   • The nail becomes permanently magnetized and cannot be switched off.
   • The nail becomes heavier but does not become magnetic.
2. 2

   Which change would make an electromagnet made from a coil and an iron nail stronger?

   • Using more turns of wire or more battery current.
   • Using fewer turns of wire or less battery current.
   • Removing the iron nail from the coil.
3. 3

   Why can an electromagnet be switched on and off?

   • Because its magnetism depends on electric current flowing through the coil.
   • Because it stays magnetized forever after the current is removed.
   • Because it works without any electric current.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.