26-12-2012, 03:13 PM
Electromagnetic Waves
Electromagnetic.pdf (Size: 952.69 KB / Downloads: 39)
Maxwell Equations
Maxwell equations state the law of:
–Electrostatic
–Magnetostatic
–Electrokinetics
–Classic magnetism
–Wave optics
–Geometrical optics
They are also used as the basis for Einstein's special relativity.
They do not explain:
–Black body radiations
–Emission and absorption spectrum of atoms
–interaction (atomic scale)
Maxwell Equations
Conducting media
Electric forces Free charges move conduction current
The metals: free electrons conduction
The semiconductors: free electrons and halls conduction
The electrolytes: positive and negative ions conduction Ex : solution NaCl (ions Na+, ions Cl-)
Gases or plasma: partially or completely dissociated material
Any medium is conducting if the applied E field is strong enough. The limit value is called „disruptive field‟, it corresponds to forcing out the charges (electric arc effect) :in the air, Ed=3MV/m=3.106 V/m
Utility
The wave is used as “carrier wave”
The modulation of an information is done on a carrier wave
EM waves are used to “transmit” data in the space
It‟s the principle of radio transmission
Electromagnetic.pdf (Size: 952.69 KB / Downloads: 39)
Maxwell Equations
Maxwell equations state the law of:
–Electrostatic
–Magnetostatic
–Electrokinetics
–Classic magnetism
–Wave optics
–Geometrical optics
They are also used as the basis for Einstein's special relativity.
They do not explain:
–Black body radiations
–Emission and absorption spectrum of atoms
–interaction (atomic scale)
Maxwell Equations
Conducting media
Electric forces Free charges move conduction current
The metals: free electrons conduction
The semiconductors: free electrons and halls conduction
The electrolytes: positive and negative ions conduction Ex : solution NaCl (ions Na+, ions Cl-)
Gases or plasma: partially or completely dissociated material
Any medium is conducting if the applied E field is strong enough. The limit value is called „disruptive field‟, it corresponds to forcing out the charges (electric arc effect) :in the air, Ed=3MV/m=3.106 V/m
Utility
The wave is used as “carrier wave”
The modulation of an information is done on a carrier wave
EM waves are used to “transmit” data in the space
It‟s the principle of radio transmission