Understanding Magnetism Concepts

Understanding Magnetism

Magnetism is a fundamental force of nature that arises from the motion of electric charges, most notably electrons. Unlike gravity, magnetism does not act at a distance between static objects but requires moving charges, currents, or magnetic materials to create its effects. Magnets exhibit two distinct classes of behavior: ferromagnetic—like iron, nickel, or cobalt—which remain permanently magnetized after being subjected to a strong magnetic field, and paramagnetic, which are attracted to magnets like iron but do not hold their magnetic properties without an external magnetic field.

Properties of Magnetism

Attraction

Magnetic attraction occurs when either two ends of one pole face each other. When two north poles repel or two south poles repel, it is referred to as repulsion. While two north poles cannot combine with each other, they can combine with a south pole to form a single magnet of opposite polarity. Two oppositely charged pipes filled with conducting liquids will generate large attractive forces if held together while rotating in the same direction. These forces depend on the strength of both the magnetic materials and the speed of rotation.

Centrifugal Force

In a spinning medium or fluid, centrifugal force causes the material to move away from the axis of rotation. If there is no friction, any body attached to the surface will experience a force directed radially outwards. However, if there is friction, then the net force acting on such an object is given by the equation F = mv^2 / r, where F is the force, m is the mass at rest, v is the velocity, and r is the radius of curvature.

Applications of Magnetism

Electric Motors

The ducted fan motor employs channel fans with radial blade profiles that provide high efficiency and low noise. The motor's magnetic field is responsible for the fan's operation. As the motor spins, the magnetic field generates lift, causing the fan to push air through the duct. The motor's fan can be powered by the motor directly or by a separate fan motor. The motor itself can also be used as a fan motor, providing a compact and efficient solution for air circulation and air conditioning.

Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) is a medical imaging technique that uses a strong magnetic field and radio waves to create detailed images of the body's internal structures. It is non-invasive and does not use radiation like CT scans, making it a valuable tool for diagnosing various medical conditions.

Magnetic Stirring

Magnetic stirring is the process of using a magnetic stirrer to mix a liquid in a vessel or container. The magnetic stirrer consists of a magnetic rod or bar that is submerged in the liquid to be stirred, a drive motor, and a controller to adjust the speed of the motor. As the motor turns, the magnetic rod creates a circular stirring motion through the interaction between the magnetic field and the current flowing through the liquid's conductive material like metal or carbon nanoparticles.

Magnetism in Everyday Life

From speakers to hard drives to smartphones, magnets play a crucial role in modern technology. Even everyday items like credit cards can contain tiny magnetic strips for electronic payment systems. Understanding magnetism allows us to develop new technologies with increased efficiency and performance, improving our daily lives in countless ways.