electromagnetic wavesWatch this thread
An electromagnetic wave is a wave that has a magnetic field and an electrical field at right angles to each other that moves along with the wave.
An electromagnetic wave is emitted by an excited electron (i think.)
So If I'm right, shouldn't all electrons emit electromagnetic waves? That's why whenever a current flows through a conductor, (current is essentially the flow of electrons or charge carriers), a magnetic field along with the electrical field is set up.
Now, given that everything I've written is correct, my question is that shouldn't everything with excited electron emit EM waves?
And how do you detect an EM wave anyway?
As an electron in an atom becomes excited (through the emission of EM waves, heat electrical current etc..), it wants to move up to a higher energy level. If provided with the exactly correct amount of energy, the electron can move up to a specific energy level. The electron has an innate need, however, to stay at ground level therefore, the atom is unstable if the electron stays at the higher energy level. It momentarily stays at that level, but as it becomes less excited it goes back down to ground level.
The process that I'm assuming you're talking about is when the electron moves from ground level to a higher level. In this process energy is lost through the emission of a photon, and the wavelength of the emitted photon depends on its energy. The electron itself doesn't emit EM waves, it is the photon (light particle) that emits an EM wave that is related to its energy.
Regarding the detection of an EM wave - we can refer back to the emission of gamma radiation from a radioactive substance. This could be carried out using a GM tube. If you are measuring the radioactivity of a substance that also happens to emit alpha and beta particles, just separate the tube and the substance with paper and a few mm's of aluminium. The only radiation you will be detecting should be from the gamma waves. I'm assuming that you're asking about the detection and not measuring.
If you have any more questions, feel free to ask I hope I've answered your question