Magnetic Fields And Magnetic Forces - SS3 Physics Lesson Note

Magnetic fields are regions in space around a magnet or a current-carrying conductor where magnetic forces are exerted on magnetic materials. The strength and direction of the magnetic field are determined by the strength and direction of the current flow or magnetization. Magnetic fields are three-dimensional, and their direction is indicated by lines of force, also known as magnetic field lines. The direction of these lines indicates the direction of the magnetic force that would be exerted on a north-seeking pole placed in the field.

Magnetic forces are exerted on magnetic materials in the presence of magnetic fields. Like charges repel each other, and opposite charges attract each other. Similarly, magnetic poles repel each other, and opposite magnetic poles attract each other. The force between two magnetic poles is proportional to the product of their pole strengths and inversely proportional to the square of the distance between them. This is known as Coulomb's Law for magnetic poles.

A moving electric charge or a current-carrying conductor creates a magnetic field around it. The direction of the magnetic field is perpendicular to the direction of the current flow and follows the right-hand rule. The strength of the magnetic field is directly proportional to the current flowing through the conductor and inversely proportional to the distance from the conductor.

Magnetic fields also interact with each other. When two magnetic fields interact, they can add or cancel each other out, depending on their relative direction and strength. The interaction of magnetic fields is important in many practical applications, such as electric motors and generators, transformers, and magnetic levitation systems.

In summary, magnetic fields are regions in space where magnetic forces are exerted on magnetic materials. Magnetic forces are similar to electric forces, with poles or charges repelling each other and opposite poles or charges attracting each other. Magnetic fields are created by moving electric charges or currents and interact with each other in various ways.