Maxwell Equation Equation 1: Gauss’s law for electric field Equation 2: Gauss’s law for magnetic field There is no magnetic monopole: north and south poles ALWAYS come in pairs Equation 3: Faraday’s Law of Induction We often use Use Len’z law to determine the direction (negative sign) Changing Magnetic field induces circular electric field. Equation 4: Ampere-Maxwell Law Changing electric field induces circular magnetic field.

Example: Maxwell Equation Indicate the equation number most relevant to each phenomenon listed in the table Electromagnetic Phenomenon Coulomb's law. The displacement current. Under static conditions, excess charge resides on the surface of a conductor. The magnetic field is not a conservative field. A changing magnetic field generates an electric field. A changing electric field generates a magnetic field. Electric charge is accompanied by an electric field. Electric current is accompanied by a magnetic field. There are no magnetic monopoles. Electromagnetic waves propagate at the speed of light. (Pick two!) (1)(2)(3) (4) x x x x x x x x x xx

Electromagnetic Wave

Electromagnetic Wave: Cont Long waveRadio Wave Infrared ultraviolet X rays Gamma rays  Wavelength (m) Frequency 

Produce EM waves Radio wave LC circuits Visible lightsThermal oscillation of atoms (heat a filament) X-rayTransition of electrons from outmost shell to inner shell. Different frequency (or wavelength) means different energy.

Scattering of EM waves: Why is Sky Blue incident transmission Scattered earth SunAir molecules Sun