I know that elecromagnetic waves are generated when an electric charge oscillates in space. ( i.e. the vibrating electric field generates a magnetic field which then generates a electric field and so on .....producing a EM wave ).
My question :
is it possible to generate ( from scratch ) an EM wave from a oscillating MAGNETIC field source ( one NOT induced by an electric field ) ?
if so, please give an example of this.
serious answers ONLY please !
2006-06-30 16:40:23 · 7 answers · asked by fullbony 4 in Science & Mathematics ➔ Physics
If magnetic monopoles existed (ie akin to positive and negative charges, maybe you might have "north" and "south" monopoles), certainly you could. All magnets are dipoles, however.
I know if you vary the dipole moment you will generate radiation, but accelerating a dipole with a constant moment? No.
So, if monopoles existed so you had magnetic "charges" you could oscillate, sure, you could make propogating EM waves.
If you have an magnet whose field strength you can oscillate (akin to moving those hypothetical magnetic monopoles closer and further apart; this is analagous to an oscillating dipole electric field) you would make EM waves.
I don't know how to make a magnetic dipole oscillate unless it is an electromagnet, which sorta violates your "induced by an electric field" though it might be more precise to say "induced by an electric current."
Oh, and in the presence of a conductor, you can do it since the oscillating magnetic field will generate oscillating electric fields, but that is cheating. I am presuming you mean JUST A MAGNET in free space, with no conductors around.
2006-06-30 17:10:54 · answer #1 · answered by Mr. Quark 5 · 1⤊ 0⤋
When ever an electric field varies there is a variation in the magnetic filed. Other words variation in electric field implies that there is an induced magnetic field and it also varies.
Similarly if a magnetic field varies then surrounding it there is varying electric field.
The electro magnetic waves whose frequencies are less than
150,000 cycles per second( wavelength more than 2000m) can not be traced, the intensity being very less.
If a magnetic field is made to oscillate with a frequency more than 150000 cycles per second E.M wave can be traced.
Practically it is impossible to make a magnet to oscillate with such great frequency and at the same time we can easily make electrons to oscillate with frequency more than this.
2006-06-30 18:22:37 · answer #2 · answered by Pearlsawme 7 · 0⤊ 0⤋
I'm not sure I understand what you are asking exactly. Just moving a magnet over a metal object will produce and EM wave in the object. That's how generators work with magnets spinning around a metal core or vice versa.
2006-06-30 16:45:40 · answer #3 · answered by Martin S 7 · 0⤊ 0⤋
Eh yes and no.
The thing is you can't isolate a magnetic "charge" (called monopoles), but you can do this with electric charges. That is you can't just have a north pole of a magnet without the south, but you CAN have a positive charge without a negative charge. That is the no part of the answer.
The yes part is that if you COULD isolate a magnetic monopole then you could wiggle it and generate EM waves.
Hope that made sense / helped.
2006-06-30 16:50:02 · answer #4 · answered by az 5 · 0⤊ 0⤋
If the magnetic oscillates trough a coil of wire it will produce a emf and current without and charge going through the wire. I'm not sure what you are exactly asking about the non induction part.
2006-06-30 16:52:51 · answer #5 · answered by Dragonheart 2 · 0⤊ 0⤋
Sure, that is how a crank generator works. It is a bar magnet moved by mechanical means to induce a current. At least that seems to be what you are asking.
2006-06-30 16:59:17 · answer #6 · answered by pechorin1 3 · 0⤊ 0⤋
Rotate a permenent magnet on an axis.
2006-06-30 18:28:17 · answer #7 · answered by Siralexe 2 · 0⤊ 0⤋