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)

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

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

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

*** IRON, COBALT, NICKEL

Magnetism Attraction and Repulsion – Opposites attract – Like poles repel

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

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

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

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

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

Will the magnetic field be clockwise or counter clock wise

What are the two poles?