Applications of Magnetism

Author: Zhiming Ou

Publisher: 3265 Public Way

ISBN: 978-1-997036-06-7

Summary:

Magnetism is one of the four fundamental interactions of nature. Together with electricity it forms electromagnetism, which governs light, radio waves, electronics, electric power systems, and most modern communication technologies. Without magnetism, there would be no electric motors, generators, computers, electric storage, MRI scanners, radios, or smartphones. It is one of the key physical phenomena that make modern civilization possible.

Magnetism comes from 3 sources: electric currents, orbital motion of electrons, and spins of subatomic particles (electrons, protons and neutrons). Under certain conditions, some valence electrons in metallic materials can be delocalized, or they can move through the material freely, and moving electrons have magnetic moments, as well as orbiting angular momentum, so, magnetic fields are created, which can interact with external magnetic fields.

According to the Biot-Savart’s Law, the first axiom of magnetism, the strength of the magnetic field produced by a collection of moving charges can be calculated as the vector sum of quantities proportional to the cross-product of the velocity and position vector of every charged particle. To increase the strength, one can increase the current density or control the direction of their velocities, through an external magnetic field created by a rotating permanent magnet.

Iron, Cobalt, nickel, gadolinium, and dysprosium are strong magnetic materials, because they contain atomic magnetic moments that tend to align parallel to each other even in a weak external magnetic field. These materials are called ferromagnets. The neodymium magnet or the alloy Nd2Fe14B is very strong and cheap; it makes devices with a motor lighter and more efficient.

We need computer programs or AI to control the frequency of rotation of the permanent magnet, so as to control the strength of the induced magnetic fields. This is the following work to be done. In this book, I summarized all the working principles for magnetism, and most applications of magnets.

 

Content

Part 1 What is Magnetism?

Magnetic Phenomena

Nature of magnetism

Types of magnets

Diamagnet and Paramagnet

 

Part 2 Properties of Magnetic Fields            17

Magnetic force

Motion of charged particles in a Magnetic Field

Electromagnetic induction

Electric Circuits with Inductors

Self inductance, mutual inductance

Energy in a magnetic field

   RLC circuits

Electromagnetic Impulse                  36

Control temperature and pressure

 

Part 3 Applications of Electromagnetism

Nikola Tesla’s Contribution to Magnetism

Electric generator

Transformer

Electric motors

Mass spectroscopy

Nuclear magnetic Resonance

Compass

Dynamic RAM

Magnetically levitated train