Brief History of Maxwell's Equations Andre-Marie Ampere - 1775 – 1836 - French physicist In 1820, a week after Ampere heard of H. C. Ørsted's 1806 discovery that a magnetic needle is acted on by a voltaic current,he presented a paper to the Academy containing a far more complete exposition of that and related phenomena. Ampere, the unit of current, and "Ampere's law" are named after him. Oersted is a unit of magnetic field. Ampere's Law: ∇×HJ ∂D = + ∂t Carl Friedrich Gauss – 1777-1855 - German mathematician Independently stated Green's theorem, generalized Coulomb’s law, and formulated separate electrostatic and electrodynamic laws, including "Gauss's laws", which constitute two of the four "Maxwell's equations." Gauss's Laws: ∇iD = ρ, ∇iB = 0 Michael Faraday - 1791-1867 - British experimentalist Discovered that moving a magnet near a loop of wire causes an electrical current to flow; this led to Faraday’s law of induction. Farad (unit of capacitance) and "Faraday's law" are named after him; also the Faraday effect (optics) and the Faraday cage. Faraday's Law: ∇×E = −∂B ∂t James Clerk Maxwell - 1831-1879 - Scottish physicist Converted Faraday’s physical ideas into a mathematical model. Suggested that Faraday’s law of induction implies a corresponding “displacement current ∂D ” that yields electromagnetic waves. ∂t Maxwell's four equations (above) suggested that electromagnetic waves could be generated in the laboratory, a possibility first demonstrated by Heinrich Hertz in 1887, eight years after Maxwell's death.MIT OpenCourseWare http://ocw.mit.edu 6.013 Electromagnetics and Applications Spring 2009 For information about citing these materials or our Terms of Use, visit:
View Full Document
Unlocking...