The discussion centers around the definition of an electromagnetic (EM) wave, exploring its characteristics, the conditions under which it is produced, and the distinction between different types of waves. Participants examine theoretical aspects and implications of wave behavior in the context of electromagnetic fields.
Participants do not reach a consensus on a single definition of an EM wave, and multiple competing views regarding the characteristics and conditions for EM wave production remain evident throughout the discussion.
The discussion highlights the complexity of defining EM waves, including the dependence on definitions of frequency, waveforms, and the nature of electromagnetic fields. There are unresolved aspects regarding the implications of combining different frequencies and the specific conditions under which EM waves are produced.
No. The wave equation is linear, so any two of its solutions can be added to yield a third. Electrical and magnetic fields also add, so if I have two oscillators at different frequencies, the resulting electrical and magnetic field will also be a solution to the wave equation. It won't be a neat pure sine wave with a definite frequency, and by adding enough different frequencies and amplitudes you can produce almost arbitrarily complicated waveforms.k9b4 said:Do we say something is an EM wave only if the EM field is oscillating at a constant frequency?
I don't know that there's a single exact definition, but I'd expect just about everyone to agree that any time-varying electromagnetic field that can be written as a sum of terms containing ##e^{i(kx-vt)}## would be one.What exactly is the definition of an EM wave?
Yes. It will be a single pulse, but it will be a wave.If an electron moves in a direction and then stops moving, is an EM wave produced by that electron?