Electromagnetism

1. Electromagnetism

2. Electromagnetism • Describes the magnetic field produced by a current-carrying wire (right-hand rule or left-hand rule) • Names ways of modifying the intensity of the magnetic field produced by a current-carrying wire (type of wire, current intensity) • Compares the behaviour of a compass in the magnetic field of a magnet with the magnetic field created by a current-carrying wire • Describes the magnetic field produced by a solenoid (right-hand rule or left-hand rule) • Names ways of changing the intensity of the magnetic field produced by a solenoid (nature of the core, intensity of the current, number of turns) • Names ways of inducing electrical current in a wire (e.g. movement of a magnet, changing the intensity of a magnetic field)

3. Electromagnetism • How do magnets react? • Right hand rule • (straight wire and solenoid) • Increase magnetic field • (straight wire and solenoid) • How to generate electricity?

4. Recap on Magnetism • Magnetism: • All phenomena caused by magnets • A magnet is an object that can attract other objects containing iron, cobalt or nickel

5. Magnetism • Have you ever noticed? • It doesn’t matter which part of the magnet you bring to iron, it will always attract to a magnet. • Why? • Iron is made up of small polarized regions called domains. Each of these act like a small magnet. When you magnetize the iron, the domains align to be attracted to the magnet. Remember opposites attract

6. *** IRON, COBALT, NICKEL

7. Magnetism • Attraction and Repulsion • Opposites attract • Like poles repel

8. Electromagnetism • Electromagnetism: • All phenomena resulting from the interaction between electricity and magnetism. • Right Hand rules: • Live Wire • Thumb points to the negative terminal • Fingers show the direction of the magnetic field

9. Electromagnetism • Right Hand rule • Solenoids (a cylindrical coil of live wire) • You fingers follow the coil and point towards the negative terminal • Your thumb indicates the magnetic North

10. Electromagnetism • How can you tell what is the negative terminal? • In the circuit drawings the negative terminal will either be identified with a – Or… • In the following symbol the shorter terminal is the negative one

11. Electromagnetism • You can generate an electrical field by… • Moving a conductor in a magnetic field • Moving a magnet around a conductor

12. Magnetic field of a life wire • The thumb points in the direction of conventional current • The fingers show the direction of the magnetic lines

13. Will the magnetic field be clockwise or counter clock wise + - + -

14. What are the two poles?