Physical Science / Unit 10: Electricity and Magnetism
10.6 Electromagnets
Notes
An electric current produces a magnetic field. A coil of wire carrying current is a solenoid, and with an iron core it becomes an electromagnet.
- Strength increases with more current, more coils (turns) and an iron core.
- It can be switched on and off, and its poles can be reversed by reversing the current.
- Uses: junkyard cranes, electric bells, MRI machines, speakers, maglev trains.
- Example: Doubling the number of turns in an electromagnet makes it stronger.
Practice
Which change would make an electromagnet stronger?
More turns, more current and an iron core all increase strength.
What is an advantage of an electromagnet over a permanent magnet?
Switching the current off turns off the magnetic field.
Moving electric charge produces:
Current in a wire creates a magnetic field around it.
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