Magnetism and Electromagnetism - SS1 Physics Past Questions and Answers - page 1

Magnets are defined by their ability to attract or repel certain materials like iron. This property is called magnetism. The other options describe different physical properties: * Conductivity: the ability to conduct electricity. * Elasticity: the ability to return to original shape after deformation. * Transparency: the ability to allow light to pass through.

Magnetism is a phenomenon associated with certain materials that exert attractive or repulsive forces on other magnetic materials. Magnets have two poles, known as the north pole and the south pole, which interact with each other. Like poles repel each other, while opposite poles attract. This behaviour is due to the alignment of magnetic domains within the material, which creates a magnetic field around the magnet. The magnetic field is responsible for the forces and interactions observed in magnets.

Permanent magnets retain their magnetism over a long period of time and do not easily lose their magnetic properties. Examples of permanent magnets include bar magnets, horseshoe magnets, and magnets made of materials like neodymium or ferrite. Temporary magnets, on the other hand, only exhibit magnetism when they are in the presence of a strong magnetic field. Once the external magnetic field is removed, they lose their magnetism. Soft iron is an example of a temporary magnet.

Explanation: The SI unit of magnetic field strength is the tesla (T). It is named after the inventor Nikola Tesla and is a measure of the strength and intensity of a magnetic field.