What is an electromagnetic wave?
93061
I didn't give it a thumbs down, and I think the answer is fine as far as it goes.  However, one problem that I noticed is that you have a circular definition.  You said electromagnetic waves are oscillating electric and magnetic waves.  I assume you meant to say electromagnetic waves are oscillating electric and magnetic *fields*, which is correct.
437435
the theory that light, and all electromagnetic radiation (radio waves, x-rays, microwaves) travels as a wave, like the ripples on a plucked string. these waves look like sine and cosine graphs.\n\n\nthis was proved to be an incomplete picture by eistein's analysis of the photoelectric effect, for which he won the nobel prize. this showed light was in fact made of particles called photons. however, quantum wave theory now tells us that all matter is both a particle and aa wave; the matter is contained in a particle, but the location of the particle is determined by a wave.
102674
Electromagnetism is the what allows information contained in electric circuits to actually leave the circuits. Althought he technique by which the information (electric signal) actually leaves the circuit is quite complicated, suffice it to say, that using an antenna, this information can be allowed to travel through air.\nCo-incidentally, even light happens to be an electromagntetic wave. So, you can say that human beings owe their vision to electromagnetism.\n\nMircowaves - an electromagnetic phenomenon allow you to exhange information with satellites, besides of course, allowing you to cook food.\n\nThink about it! Radio, Mobile phone communication etc. all owes its existence to electromagnetism.\n\nThis is course is with respect to electromagnetic wave phenomeona. When you actually think about the fact that one can create artificial magnetics using electric current, the possibilities are limitless
477826
heat is not electromagnetic radiation, it's molecular kinetic energy (or thermal energy).  The sun emits Ultraviolet radiation, amongst other emissions in the light spectra, but i don't believe the heat emitted can be attributed to an electromagnetic wave.
503096
What do you mean exactly? A transverse magnetic wave is just an electromagnetic wave. All electromagnetic waves can be polarized, and if you have 2 mediums the angle of incidence at which all light is polarized in one direction (parallel to the plane separating, for example, water from air) is given by (theta) = arctan(n2/n1). The magnetic component of the transverse wave is perpendicular to it. Are you looking for an equation? If yes, what does it have to relate? Add more detail please.
1073057
Synchrotron radiation is electromagnetic radiation, similar to cyclotron radiation, but generated by the acceleration of ultrarelativistic (i.e., moving near the speed of light) electrons through magnetic fields. This may be achieved artificially by storage rings in a synchrotron, or naturally by fast moving electrons moving through magnetic fields in space. The radiation typically includes infrared, optical, ultraviolet, x-rays.
267999
Light is an electromagnetic wave, like radio waves, governed by Maxwell's Equations:\n\nhttp://en.wikipedia.org/wiki/Maxwell%27s_equations\n\nThis means there are both electric and magnetic waves travelling together; one cannot exist without the other. The energy of the light trades back and forth between the electric and magnetic waves continuously. \n\nNeat thing to consider - metals are shiny because they are conductors! The electric field hits the metal and is cancelled out - a conductor won't allow a voltage difference between two points. The current which flows through the conductor creates a magnetic field which radiates away at 90 degrees to the source. That magnetic field collapses and creates an electric field... effectively, a new light beam! And that is how reflections work.\n\nNo conductor is perfect, of course, so some of that electric current in the surface of the conductor causes resistive heating. This is the reason why a fork left on a sunny picnic table will get a lot hotter than the surrounding air. \n\nFreakier still is that light has mass, which demonstrates that waves and fundamental forces seem to be carried by some sort of "messenger particle", though that's well outside the scope of this Electrical Engineer's theoretical physics training!
343884
Electromagnetic Radiation\n\nElectromagnetic radiation is the result of oscillating electric and magnetic fields. The wave of energy generated by such vibrations moves through space at the speed of light. And well it should... for visible light is indeed one form of electromagnetic (EM) radiation.
738961
Sorry, you're going to have to be a bit more specific than that. Electromagnetics is a rather broad subject.\n\n~X~
206005
The "aether" was thought to be a medium through which electromagnetic waves travel.  The idea was based on the notion that sound had to travel through something (solid, liquid, or gas) in order to be heard.  The existence of the aether has been disproven.
844222
radio waves..\nand how is this a biology question?
190626
The visible spectrum (or sometimes optical spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light.\n\nCheck the attached link for visible response.
448469
In electrical engineering, it's the study of electromagnetic fields which are combinations of electric and magnetic fields that propagate in transmission lines or in space. Read about "Maxwell's Equations" to get the history of field theory. It's probably the toughest subject to study and understand in electrical engineering because Maxwell's Equations use differential and integral calculus to develop field theory.
237286
Electromagnetic waves are light, radio, UV, infra-red, gamma, micorwaves and go at the speed of light 186,000 miles per second (although they go a bit slower in matter). The waves themselves consist of vibrating electric and magnetic fields. Probably you know a few uses for these. For example, our eyes pick up EM waves and that allows us to *see*.\n\nSound waves are pressure waves in some material. Their speed depends on the material. Sounds goes through air at about 700 miles per hour. This is considerable slower than light.\nThese are the waves that our ears hear.\n\nWater waves are what you see on the surface of water when you throw a stone into the water. These go a *lot* slower even than sound waves.
745636
The main concept to understand is that of a carrier wave.  The radio wave is that.  A radio wave is electro-magnetic radiation, which, unlike other waves, is not a vibration within a medium, like sound waves for example, which are the propagation of alternating high and low pressure within the air, or other fluid media.  Electro-magnetic waves are a self propagating electro-magnetic effect which can travel even in a vacuum.  Electro-magnetic radiation is a pulsing stream of energy where the pulses are at a constant frequency.  What we perceive as different phenomenon are in fact the same electromagnetic radiation but at different frequencies.  Microwaves, Radio, Ultra-violet, Visible Light, and Infra-red, are all electro-magnetic radiation moving down the scale from high to low frequency.\n\nThe radio transmitter sends out radio waves at a specific frequency or band of frequencies.  The aerial of the receiver develops tiny electric currents in it as the radio wave flows past it.  These are pulsing currents at the same frequency as the radio wave, but these pulses are not in themselves the content of speech or music.  This content, or signal, is carried in the wave, hence the concept of the carrier wave.\n\nIt is easier to understand Amplitude Modulation or AM radio so I will restrict myself to that.  If you imagine a radio wave as a very long string with the pulses like beads on it, all spaced at precise intervals, then imagine that the beads slowly getter bigger and smaller along its length.  Each bead is a packet of energy in the wave and all occur at the same frequency, but where the beads get bigger there is more energy in the packet.  It only takes a little more imagination now to see how the pattern of a sound wave can be represented by the bulging out of the beads, and their getting smaller.  This is called the amplitude.\n\nLooking at it in practical terms, at the transmitter end sound is converted in the microphone into a corresponding pattern of changes in the current flowing through the microphone.  That is your signal.  That signal which is at a low electrical power, is used to create the same pattern but in a circuit of much higher electrical power - that is what an amplifier does.  The device used to transfer the pattern is called a transistor, which uses the low powered circuit to control the flow in the high powered circuit.\n\nThe amplified signal is fed to the transmitter aerial, so now that pattern of electrical energy, identical to the pattern of the sound picked up by the microphone, comes out of the aerial as radio waves, with the pattern held in the varying amplitude of the radio wave.\n\nNow comes a trick to follow.  If there are thousands of transmitters all radiating radio waves all over the place, how come your radio only picks up the one signal.  This is where the tuner comes in.  The principle of radio tuning depends on the opposite properties of coils and capacitors.  I don't know if you know what these are, but it doesn't matter if you don't.  Both of these devices have a special kind of resistance to electricity known as impedance.  Impedance only operates where the current is varying.  The voltages and currents in our radio Ariel will be varying at exactly the same frequency as each radio wave it is exposed to, so if we pass that current through either a coil or a capacitor there will be an impedance in the circuit.  Now the impedance of the coil increases as the frequency gets higher and the impedance of the capacitor gets higher as the frequency gets lower.  An AM tuning circuit simply passes the signal current through both a coil and a capacitor at the same time, and the capacitor is a mechanically variable one, so by turning a knob you can increase or decrease the capacitance.  The trick here is that as the capacitance changes the circuit will show least impedance to a specific frequency compared with all the others, so provided the frequencies are not too close, as the law requ
46196
I hope you don't take this to be something of a cop-out answer. Light is itself an electromagnetic field that is carrying energy through space -- commonly called an electromagnetic wave or 'light'. It is this wave that really makes things visible.\n\nConversely, if you have no electromagnetic wave or one of an invisible wavelength, (at least to the human eye) then it won't bounce off of the object or if it does it won't be visible when it reaches you.\n\nThe visible properties of an object are determined by how EM waves interact with the electrons near the surface of an object. These interactions are what make shiny things shiny (for instance).
279774
Light and sound both travel through waves, though light travels fatser than sound. Light does not require any medium for transport, so it is called an electromagnetic wave. Sound however needs a medium as it is transmitted through the vibrations of the particles of the medium. It is called a mechanical wave.