This chapter covers the properties of magnets, the magnetic effect of current, the force on a current-carrying conductor, electromagnetic induction and the devices built on them: the electric motor, the electric generator, the transformer and everyday applications of electromagnets (speaker, Maglev trains and medical equipment).
1. Magnets – Natural and Artificial
- There are two kinds of magnets around us: natural magnets and artificial magnets.
- Natural magnets exist in nature and are found in rocks and sandy deposits in various parts of the world.
- The strongest natural magnet is lodestone magnetite.
- The magnetic property of natural magnets is permanent – it never gets destroyed.
- Lodestones were used to make compasses in the olden days; ship captains used magnets to identify the direction of the ship in the sea.
- The magnets available in shops are basically artificial magnets.