All articles starting with E
17,681 articles
Electromagnetic induction
Electromagnetic induction, also called magnetic induction, is the production of a voltage in a conductor when magnetic flux through it changes; Michael Faraday discovered the effect in 1831.
Electromagnetic interference
Electromagnetic interference (EMI), also known as radio frequency interference, is the degradation of equipment or system performance caused by an electromagnetic disturbance such as lightning.
Electromagnetic invariants
Electromagnetic invariants are scalar combinations of the electric and magnetic fields, B² − E² and E·B, that take the same value in every inertial frame.
Electromagnetic mass
Electromagnetic mass is the mass attributed to the energy of a charged particle's own electric and magnetic field, an idea introduced by J.J. Thomson in 1881.
Electromagnetic Phenomena
Electromagnetic phenomena (MeSH D055590): electricity, magnetism, charged particles, fields, and electromagnetic radiation. Covers Maxwell's theory, the spectrum from radio to gamma rays, and medical uses.
Electromagnetic pulse
An electromagnetic pulse (EMP) is an intense, short burst of electromagnetic radiation that can disrupt or damage electronics, produced by nuclear detonations, non-nuclear devices, or solar storms.
Electromagnetic pump
An electromagnetic pump is a pump that moves electrically conducting liquids, usually liquid metals, using Lorentz forces instead of a mechanical impeller, so no moving parts touch the fluid.
Electromagnetic radiation
Electromagnetic radiation, also called EM radiation or EM waves, is energy carried through space by oscillating electric and magnetic fields at light speed, ranging from radio waves to gamma rays.
Electromagnetic radiation and health
Electromagnetic radiation and health: how ionizing radiation (X-rays, gamma) and non-ionizing radiation (radiofrequency, power fields) affect the body, dose thresholds, cancer evidence, IARC Group 2B, and ICNIRP exposure limits.
Electromagnetic scalar and vector potentials
The electromagnetic scalar and vector potentials are auxiliary fields from which the electric and magnetic fields are computed; gauge freedom means many potential pairs give the same fields.
Electromagnetic shielding
Electromagnetic shielding, also known as RF shielding, blocks electromagnetic fields using conductive or magnetic materials so interference neither enters nor leaves protected electronics, a key method for achieving electromagnetic compatibility.
Electromagnetic spectrum
The electromagnetic spectrum is the entire range of electromagnetic radiation arranged by frequency or wavelength, from radio waves through visible light to gamma rays, with no sharp boundaries between bands.
Electromagnetic stress–energy tensor
The electromagnetic stress–energy tensor describes the density and flux of energy and momentum carried by an electromagnetic field, and serves as a source term in Einstein's field equations.
Electromagnetic suspension
Electromagnetic suspension (EMS) is a maglev method in which vehicle electromagnets attract it upward toward a ferromagnetic track, holding a small actively controlled gap at all speeds.
Electromagnetic tensor
The electromagnetic tensor, also called the Faraday tensor or field strength tensor, combines electric and magnetic fields into one object that transforms correctly between inertial frames in special relativity.
Electromagnetic tomography
Electromagnetic tomography is a geophysical method that reconstructs subsurface electrical conductivity from electromagnetic field measurements made at the surface, in boreholes, or from the air.
Electromagnetic transient simulation
Electromagnetic transient (EMT) simulation is a time-domain numerical method computing instantaneous power network voltages and currents during fast disturbances like switching, faults, and lightning, introduced by Hermann Dommel in 1969.
Electromagnetic warfare
Electromagnetic warfare (EW), formerly electronic warfare, is military action exploiting the electromagnetic spectrum for situational awareness and offensive and defensive effects: jamming, protection, and support across air, land, sea, space, and cyber domains.
Electromagnetic wave equation
The electromagnetic wave equation is the second-order partial differential equation, derived from Maxwell's equations, that governs how electric and magnetic fields propagate as waves at the speed of light.
Electromagnetically induced transparency
Electromagnetically induced transparency (EIT) is a quantum interference effect in which a coupling laser makes an absorbing medium transparent, dramatically slowing light for storage and sensing.
Electromagnetism
Electromagnetism, also called electricity and magnetism, is the branch of physics treating electric and magnetic phenomena as one field, unified by James Clerk Maxwell's equations of 1865 and underlying technologies from radio and Wi-Fi to lasers.
Electromechanical wave imaging
Electromechanical wave imaging (EWI) is a noninvasive, non-ionizing ultrasound method using frame rates up to 2000 per second to map the heart's contraction sequence and localize arrhythmias.
Electromechanics
Electromechanics, also called electromechanical engineering, is the branch of engineering concerned with converting energy between electrical and mechanical forms, chiefly in motors, generators, transformers, sensors, and actuators.
Electromembrane extraction
Electromembrane extraction (EME) is a liquid-phase microextraction technique, first published in 2006, in which a dc electric field drives charged analytes across a supported liquid membrane for sample preparation.
Electromigration
Electromigration is the current-driven transport of metal atoms in a conductor: moving electrons push metal ions toward the anode, forming voids that open chip interconnects and limit integrated-circuit lifetime.
Electromotive force
Electromotive force, or emf, is the energy supplied per unit charge by a source like a battery, generator, or solar cell, measured in volts despite its misleading name.
Electromyography
Electromyography (EMG), an electrodiagnostic test recording muscle electrical activity at rest and during contraction, usually paired with nerve conduction studies to diagnose nerve and muscle disorders such as carpal tunnel syndrome and ALS.
Electron
The electron, also called the beta minus particle, is a stable, negatively charged elementary particle, the first to be discovered, by J. J. Thomson in 1897.
Electron affinity
Electron affinity (EA), also called electron gain enthalpy, is the energy released when a neutral gas-phase atom or molecule attaches an electron; chlorine has the most negative value.
Electron attachment
Electron attachment is the capture of a low-energy electron by an atom or molecule to form a negative ion, proceeding nondissociatively to a parent anion or dissociatively to fragment anions.