L2 Physical Science Electricity Magnetism

TOPIC: ELECTRICITY AND MAGNETISM Lecturer :Semase M.P Physicalfrom Downloaded Sciences L2 hlayiso.com Sefikeng Campus

Subject outcome Identify, describe and apply principles of magnetism Learning outcomes *Draw and label diagrams showing magnetic field of permanent magnets. *Describe the effect of poles from permanent magnets exert on each other. *Identify and describe the earth’s magnetic field, magnetic declination and compass. Downloaded from hlayiso.com

Introduction Electricity and magnetism are two related phenomena produced by the electromagnetic force. Together they form electromagnetism. A moving electric charge generates a magnetic field. A magnetic field induces electric charge movement, producing an electric current. Downloaded from hlayiso.com

2. First law of magnetism 1. Properties 3. Earth’s of magnet Learning magnetic field outcomes Downloaded from hlayiso.com

Properties of magnet Electromagnets- Magnets that are not permanently magnetic. They become magnets due to an electric current going through a coil of wire. Attractive property - magnets attracts materials like iron, cobalt and nickel Repulsive properties - Magnetic poles repel each other and unlike magnetic poles attract each other Directive property - A freely suspended magnet always point in a north-south direction Downloaded from hlayiso.com

First law of magnetism The first law of magnetism states that like poles repel each other and unlike poles attract each other. *This can easily be seen by attempting to place like poles of two magnets together. *The magnetic character of domains comes from the presence of even smaller units, called dipoles. *Dipole deals with the separation of the positive and negative charges found in any electromagnetic system. * Example of this system is a pair of electric charges of magnitude but opposite sign separated by small distance. Downloaded from hlayiso.com

Earth’s magnetic field • The earth has its own magnetic field • Earth’s core contains iron, it is molten and too hot be magnetised like a permanent magnet. • The difference between the earth’s true north and compass needle direction is called declination or the angle of declination Downloaded from hlayiso.com

Summary • Magnetic material are able to attract iron • Like poles repel each-other and unlike poles attract each-other • The angle of declination is the angle between true north of the earth and compass needle direction Downloaded from hlayiso.com

Summative Assessment Page 71 Downloaded from hlayiso.com

END Downloaded from hlayiso.com