Magnetism A magnetic quadrupole Magnetism is a class of physical phenomena that includes forces exerted by magnets on other magnets. It has its origin in electric currents and the fundamental magnetic moments of elementary particles. These give rise to a magnetic field that acts on other currents and moments. All materials are influenced to some extent by a magnetic field. The magnetic state (or phase) of a material depends on temperature (and other variables such as pressure and the applied magnetic field) so that a material may exhibit more than one form of magnetism depending on its temperature, etc. History[edit] In ancient China, the earliest literary reference to magnetism lies in a 4th-century BC book named after its author, The Master of Demon Valley (鬼谷子): "The lodestone makes iron come or it attracts it Alexander Neckam, by 1187, was the first in Europe to describe the compass and its use for navigation. Michael Faraday, 1842 Sources of magnetism[edit] Topics[edit] Diamagnetism[edit]
Math and Physics Java Applets by Paul Falstad Oscillations and Waves Acoustics Signal Processing Electricity and Magnetism: Statics Electrodynamics Quantum Mechanics Linear Algebra Vector Calculus Thermodynamics Mechanics Miscellaneous Licensing info. Links to other educational sites with math/physics-related information or java applets useful for teaching: And when you get tired of learning, here is some fun stuff: Pong Simulation Circuit-level simulation of original 1972 Pong. Ionization Process by which atoms or molecules acquire charge by gaining or losing electrons Ionization (or ionisation) is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion. Ionization can result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules and ions, or through the interaction with electromagnetic radiation. Uses[edit] Everyday examples of gas ionization are such as within a fluorescent lamp or other electrical discharge lamps. Production of ions[edit] Negatively charged ions are produced when a free electron collides with an atom and is subsequently trapped inside the electric potential barrier, releasing any excess energy. Adiabatic ionization[edit] Ionization energy of atoms[edit] Semi-classical description of ionization[edit] Tunnel ionization[edit] where
List of particles List of particles in matter including fermions and bosons This is a list of known and hypothesized particles. Standard Model elementary particles[edit] Fermions[edit] Fermions are one of the two fundamental classes of particles, the other being bosons. Fermion particles are described by Fermi–Dirac statistics and have quantum numbers described by the Pauli exclusion principle. Fermions have half-integer spin; for all known elementary fermions this is 1⁄2. Quarks[edit] Leptons[edit] ^ A precise value of the electron mass is 0.51099895000(15) MeV/c2.[6]^ A precise value of the muon mass is 105.6583755(23) MeV/c2.[7] Bosons[edit] Bosons are one of the two fundamental particles having integral spinclasses of particles, the other being fermions. According to the Standard Model, the elementary bosons are: The Higgs boson is postulated by the electroweak theory primarily to explain the origin of particle masses. Hypothetical particles[edit] Graviton[edit] Other hypothetical bosons and fermions[edit]
History of electromagnetism The history of electromagnetic theory begins with ancient measures to deal with atmospheric electricity, in particular lightning.[1] People then had little understanding of electricity, and were unable to scientifically explain the phenomena.[2] In the 19th century there was a unification of the history of electric theory with the history of magnetic theory. It became clear that electricity should be treated jointly with magnetism, because wherever electricity is in motion, magnetism is also present.[3] Magnetism was not fully explained until the idea of magnetic induction was developed.[4] Electricity was not fully explained until the idea of electric charge was developed. Ancient and classical history[edit] The knowledge of static electricity dates back to the earliest civilizations, but for millennia it remained merely an interesting and mystifying phenomenon, without a theory to explain its behavior and often confused with magnetism. Middle Ages and the Renaissance[edit]
Plasma (physics) State of matter Early history Except near the electrodes, where there are sheaths containing very few electrons, the ionized gas contains ions and electrons in about equal numbers so that the resultant space charge is very small. We shall use the name plasma to describe this region containing balanced charges of ions and electrons. Definitions The fourth state of matter Plasma is distinct from the other states of matter. Ideal plasma Non-neutral plasma Dusty plasma Properties and parameters Density and ionization degree For plasma to exist, ionization is necessary. , that is, the number of charge-contributing electrons per unit volume. is defined as fraction of neutral particles that are ionized: where is the ion density and the neutral density (in number of particles per unit volume). . , where is the average ion charge (in units of the elementary charge). Temperature Plasma potential Since plasmas are very good electrical conductors, electric potentials play an important role. Magnetization Fluid model
Antimatter In modern physics, antimatter is defined as a material composed of the antiparticle (or "partners") to the corresponding particles of ordinary matter. In theory, a particle and its anti-particle (e.g., proton and antiproton) have the same mass as one another, but opposite electric charge and other differences in quantum numbers. For example, a proton has positive charge while an antiproton has negative charge. A collision between any particle and its anti-particle partner is known to lead to their mutual annihilation, giving rise to various proportions of intense photons (gamma rays), neutrinos, and sometimes less-massive particle–antiparticle pairs. Annihilation usually results in a release of energy that becomes available for heat or work. The amount of the released energy is usually proportional to the total mass of the collided matter and antimatter, in accordance with the mass–energy equivalence equation, E = mc2.[1] Formal definition[edit] History of the concept[edit] Notation[edit]
Standard Model The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, as well as classifying all the subatomic particles known. It was developed throughout the latter half of the 20th century, as a collaborative effort of scientists around the world.[1] The current formulation was finalized in the mid-1970s upon experimental confirmation of the existence of quarks. Since then, discoveries of the top quark (1995), the tau neutrino (2000), and more recently the Higgs boson (2013), have given further credence to the Standard Model. Although the Standard Model is believed to be theoretically self-consistent[2] and has demonstrated huge and continued successes in providing experimental predictions, it does leave some phenomena unexplained and it falls short of being a complete theory of fundamental interactions. Historical background[edit] Overview[edit] Particle content[edit] Fermions[edit] Gauge bosons[edit] Higgs boson[edit] Challenges[edit]
Ion Particle, atom or molecule with a net electrical charge An ion ()[1] is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. A cation is a positively charged ion with fewer electrons than protons[2] while an anion is a negatively charged ion with more electrons than protons.[3] Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. History of discovery The word ion was coined from Greek neuter present participle of ienai (Greek: ἰέναι), meaning "to go". Characteristics Ions in their gas-like state are highly reactive and will rapidly interact with ions of opposite charge to give neutral molecules or ionic salts. Anions and cations Anion (−) and cation (+) indicate the net electric charge on an ion. Chemistry
Lepton A lepton is an elementary, spin-1⁄2 particle that does not undergo strong interactions, but is subject to the Pauli exclusion principle.[1] The best known of all leptons is the electron, which governs nearly all of chemistry as it is found in atoms and is directly tied to all chemical properties. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons), and neutral leptons (better known as neutrinos). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium, while neutrinos rarely interact with anything, and are consequently rarely observed. The first charged lepton, the electron, was theorized in the mid-19th century by several scientists[3][4][5] and was discovered in 1897 by J. J. Thomson.[6] The next lepton to be observed was the muon, discovered by Carl D. Leptons are an important part of the Standard Model. Etymology[edit] Following a suggestion of Prof. History[edit] Properties[edit]