HOME  TheInfoList.com 
Electromagnetic Radiation In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through spacetime, carrying electromagnetic radiant energy.[1] It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, Xrays, and gamma rays.[2] Classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric and magnetic fields that propagate at the speed of light through a vacuum. The oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy and wave propagation, forming a transverse wave. The wavefront of electromagnetic waves emitted from a point source (such as a light bulb) is a sphere. The position of an electromagnetic wave within the electromagnetic spectrum could be characterized by either its frequency of oscillation or its wavelength [...More...]  "Electromagnetic Radiation" on: Wikipedia Yahoo 

Electromagnetic Waves (journal) Progress in Electromagnetics Research is a peerreviewed open access scientific journal covering all aspects of electromagnetic theory and applications. It was established in 1989 as Electromagnetic Waves. The editorsinchief are Weng Cho Chew (University of Illinois at Urbana–Champaign) and Sailing He (Royal Institute of Technology). Jin Au Kong was the founding editorinchief. Abstracting and indexing[edit] The journal is abstracted and indexed by the Science Citation Index Expanded, Current Contents, Inspec, Scopus, and Compendex. It is also a member of CrossRef. According to the Journal Citation Reports, the journal had a 2011 impact factor of 5.298.[1] However, it was not listed in 2012 because of "anomalous citation patterns resulting in a significant distortion of the Journal Impact Factor, so that the rank does not reflect the journal's citation performance in the literature".[2] References[edit]^ "Progress in Electromagnetics Research" [...More...]  "Electromagnetic Waves (journal)" on: Wikipedia Yahoo 

Transverse Wave A transverse wave is a moving wave that consists of oscillations occurring perpendicular (right angled) to the direction of energy transfer (or the propagation of the wave). If a transverse wave is moving in the positive xdirection, its oscillations are in up and down directions that lie in the y–z plane. Light Light is an example of a transverse wave, while sound is a longitudinal wave. A ripple in a pond and a wave on a string are easily visualized as transverse waves.Contents1 Explanation1.1 "Polarized" waves 1.2 Electromagnetic waves2 See also 3 References 4 External linksExplanation[edit] Transverse waves are waves that are oscillating perpendicularly(at a right angle)to the direction of propagation. If you anchor one end of a ribbon or string and hold the other end in your hand, you can create transverse waves by moving your hand up and down. Notice though, that you can also launch waves by moving your hand sidetoside [...More...]  "Transverse Wave" on: Wikipedia Yahoo 

Electric Potential An electric potential (also called the electric field potential, potential drop or the electrostatic potential) is the amount of work needed to move a unit positive charge from a reference point to a specific point inside the field without producing any acceleration. Typically, the reference point is Earth or a point at Infinity, although any point beyond the influence of the electric field charge can be used. According to classical electrostatics, electric potential is a scalar quantity denoted by V, equal to the electric potential energy of any charged particle at any location (measured in joules) divided by the charge of that particle (measured in coulombs). By dividing out the charge on the particle a quotient is obtained that is a property of the electric field itself. This value can be calculated in either a static (timeinvariant) or a dynamic (varying with time) electric field at a specific time in units of joules per coulomb (J C−1), or volts (V) [...More...]  "Electric Potential" on: Wikipedia Yahoo 

Electrical Network An electrical network is an interconnection of electrical components (e.g. batteries, resistors, inductors, capacitors, switches) or a model of such an interconnection, consisting of electrical elements (e.g. voltage sources, current sources, resistances, inductances, capacitances). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. Linear electrical networks, a special type consisting only of sources (voltage or current), linear lumped elements (resistors, capacitors, inductors), and linear distributed elements (transmission lines), have the property that signals are linearly superimposable. They are thus more easily analyzed, using powerful frequency domain methods such as Laplace transforms, to determine DC response, AC response, and transient response. A resistive circuit is a circuit containing only resistors and ideal current and voltage sources [...More...]  "Electrical Network" on: Wikipedia Yahoo 

Eddy Current Eddy currents Eddy currents (also called Foucault currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor due to Faraday's law of induction. Eddy currents Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. They can be induced within nearby stationary conductors by a timevarying magnetic field created by an AC electromagnet or transformer, for example, or by relative motion between a magnet and a nearby conductor. The magnitude of the current in a given loop is proportional to the strength of the magnetic field, the area of the loop, and the rate of change of flux, and inversely proportional to the resistivity of the material. By Lenz's law, an eddy current creates a magnetic field that opposes the change in the magnetic field that created it, and thus eddy currents react back on the source of the magnetic field [...More...]  "Eddy Current" on: Wikipedia Yahoo 

Lenz's Law Lenz's law Lenz's law (pronounced /ˈlɛnts/), named after the physicist Heinrich Friedrich Emil Lenz who formulated it in 1834,[1] states that the direction of current induced in a conductor by a changing magnetic field due to induction is such that it creates a magnetic field that opposes the change that produced it. Lenz's law [...More...]  "Lenz's Law" on: Wikipedia Yahoo 

Magnetic Moment The magnetic moment of a magnet is a quantity that determines the torque it will experience in an external magnetic field. A loop of electric current, a bar magnet, an electron, a molecule, and a planet all have magnetic moments. The magnetic moment may be considered to be a vector having a magnitude and direction. The direction of the magnetic moment points from the south to north pole of the magnet (inside the magnet). The magnetic field produced by the magnet is proportional to its magnetic moment. More precisely, the term magnetic moment normally refers to a system's magnetic dipole moment, which produces the first term in the multipole expansion of a general magnetic field [...More...]  "Magnetic Moment" on: Wikipedia Yahoo 

Gauss's Law For Magnetism In physics, Gauss's law Gauss's law for magnetism is one of the four Maxwell's equations that underlie classical electrodynamics. It states that the magnetic field B has divergence equal to zero,[1] in other words, that it is a solenoidal vector field. It is equivalent to the statement that magnetic monopoles do not exist.[2] Rather than "magnetic charges", the basic entity for magnetism is the magnetic dipole. (If monopoles were ever found, the law would have to be modified, as elaborated below.) Gauss's law Gauss's law for magnetism can be written in two forms, a differential form and an integral form. These forms are equivalent due to the divergence theorem. The name " Gauss's law Gauss's law for magnetism"[1] is not universally used [...More...]  "Gauss's Law For Magnetism" on: Wikipedia Yahoo 

Lorentz Force In physics (particularly in electromagnetism) the Lorentz force Lorentz force is the combination of electric and magnetic force on a point charge due to electromagnetic fields. A particle of charge q moving with velocity v in the presence of an electric field E and a magnetic field B experiences a force F = q E + q v × B displaystyle mathbf F =qmathbf E +qmathbf v times mathbf B (in SI units[1][2]) [...More...]  "Lorentz Force" on: Wikipedia Yahoo 

Electromagnetic Induction Electromagnetic or magnetic induction is the production of an electromotive force (i.e., voltage) across an electrical conductor in a changing magnetic field. Michael Faraday Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk Maxwell James Clerk Maxwell mathematically described it as Faraday's law of induction. Lenz's law Lenz's law describes the direction of the induced field [...More...]  "Electromagnetic Induction" on: Wikipedia Yahoo 

Faraday's Law Of Induction Faraday's law of induction Faraday's law of induction is a basic law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (EMF)—a phenomenon called electromagnetic induction. It is the fundamental operating principle of transformers, inductors, and many types of electrical motors, generators and solenoids.[1][2] The Maxwell–Faraday equation is a generalization of Faraday's law, and is listed as one of Maxwell's equations.Contents1 History 2 Faraday's law2.1 Qualitative statement 2.2 Quantitative 2.3 Maxwell–Faraday equation3 Proof of Faraday's law 4 EMF for nonthinwire circuits 5 Faraday's law and relativity5.1 Two phenomena 5.2 Einstein's view6 See also 7 References 8 Further reading 9 External linksHistory[edit]A diagram of Faraday's iron ring apparatus [...More...]  "Faraday's Law Of Induction" on: Wikipedia Yahoo 

Maxwell Stress Tensor The Maxwell stress tensor Maxwell stress tensor (named after James Clerk Maxwell) is a symmetric secondorder tensor used in classical electromagnetism to represent the interaction between electromagnetic forces and mechanical momentum. In simple situations, such as a point charge moving freely in a homogeneous magnetic field, it is easy to calculate the forces on the charge from the Lorentz force Lorentz force law. When the situation becomes more complicated, this ordinary procedure can become impossibly difficult, with equations spanning multiple lines. It is therefore convenient to collect many of these terms in the Maxwell stress tensor, and to use tensor arithmetic to find the answer to the problem at hand. In the relativistic formulation of electromagnetism, the Maxwell's tensor appears as a part of the electromagnetic stress–energy tensor which is the electromagnetic component of the total stress–energy tensor [...More...]  "Maxwell Stress Tensor" on: Wikipedia Yahoo 

Displacement Current In electromagnetism, displacement current density is the quantity ∂D/∂t appearing in Maxwell's equations Maxwell's equations that is defined in terms of the rate of change of D, the electric displacement field. Displacement current density has the same units as electric current density, and it is a source of the magnetic field just as actual current is. However it is not an electric current of moving charges, but a timevarying electric field. In physical materials (as opposed to vacuum), there is also a contribution from the slight motion of charges bound in atoms, called dielectric polarization. The idea was conceived by James Clerk Maxwell James Clerk Maxwell in his 1861 paper On Physical Lines of Force, Part III in connection with the displacement of electric particles in a dielectric medium. Maxwell added displacement current to the electric current term in Ampère's Circuital Law [...More...]  "Displacement Current" on: Wikipedia Yahoo 

Magnetic Potential The term magnetic potential can be used for either of two quantities in classical electromagnetism: the magnetic vector potential, A, (often simply called the vector potential) and the magnetic scalar potential, ψ. Both quantities can be used in certain circumstances to calculate the magnetic field. The more frequently used magnetic vector potential, A, is defined such that the curl of A is the magnetic field B. Together with the electric potential, the magnetic vector potential can be used to specify the electric field, E as well. Therefore, many equations of electromagnetism can be written either in terms of the E and B, or in terms of the magnetic vector potential and electric potential [...More...]  "Magnetic Potential" on: Wikipedia Yahoo 

Magnetization In classical electromagnetism, magnetization or magnetic polarization is the vector field that expresses the density of permanent or induced magnetic dipole moments in a magnetic material. The origin of the magnetic moments responsible for magnetization can be either microscopic electric currents resulting from the motion of electrons in atoms, or the spin of the electrons or the nuclei. Net magnetization results from the response of a material to an external magnetic field, together with any unbalanced magnetic dipole moments that may be inherent in the material itself; for example, in ferromagnets. Magnetization Magnetization is not always uniform within a body, but rather varies between different points. Magnetization Magnetization also describes how a material responds to an applied magnetic field as well as the way the material changes the magnetic field, and can be used to calculate the forces that result from those interactions [...More...]  "Magnetization" on: Wikipedia Yahoo 