Introduction To Magnetism - SS3 Physics Lesson Note

 Magnetism is a fundamental property of matter that results from the movement of electric charges. It is a force that can attract or repel certain materials, such as iron, nickel, and cobalt. The study of magnetism is important in many areas of science and technology, from understanding the behaviour of materials to the operation of electric motors and generators.

The key concepts related to magnetism are magnetic fields, magnetic poles, and magnetic materials. A magnetic field is an area in which a magnetic force can be detected. Magnetic poles are the points on a magnet where the magnetic field is strongest, and they are always found in pairs, with a north pole and a south pole. Magnetic materials, such as iron and nickel, can become magnetized when they are placed in a magnetic field.

Magnetic fields are created by moving electric charges, such as the flow of electric current through a wire. The strength and direction of a magnetic field can be measured using a device called a magnetometer. The magnetic field lines form loops that travel from the north pole of a magnet to its south pole.

Magnetic fields can also interact with each other in various ways. For example, like poles of two magnets will repel each other, while opposite poles will attract. This behaviour is similar to the interaction of electric charges, with like charges repelling each other and opposite charges attracting.

The study of magnetism has many practical applications. Magnetic materials are used in a variety of devices, from electric motors and generators to computer hard drives and credit card strips. Magnetic fields are also used in medical imaging technologies, such as magnetic resonance imaging (MRI). Additionally, Earth's magnetic field plays an important role in protecting our planet from the solar wind, a stream of charged particles that flows from the Sun.