- #1
fluidistic
Gold Member
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In the case of plane waves, E is orthogonal to B and they're both orthogonal to the direction of propagation, call it k.
I'm not sure I'm picturing well what such an EM wave is. For instance I know that E and B oscillates with respect to time.
Without looking to quantum electrodynamics that I don't know at all, let's say I have such a wave with a huge amplitude. I.e. the E and B fields are really strong. Does that mean that the EM wave occupy more place than a similar EM wave but with a low amplitude?
In fact I'm not sure whether the EM wave can be pictured as a line or as a 2 orthogonal "sine functions" in the 3d world. If the latter case is correct then a bigger amplitude seems to imply that the EM wave indeed occupy more place than a EM with a lower amplitude. My problem arises if say I have an enormous amplitude of E and B and that the frequency of the wave is about [tex]10^{-6}Hz[/tex]. It could be possible in this example that in a time of about [tex]1/10^{-6}s[/tex], the space perturbation (the EM wave traveling) can reach say a distance of about 300 000 km from the source which is about [tex]10^{6}[/tex] times faster than the speed of light which is of course impossible. I understand that in the direction k the speed of the wave is c, or the speed of light. But I'm not understanding if the amplitude of the wave is related to the wave's place in the 3d world.
I'm not sure I'm picturing well what such an EM wave is. For instance I know that E and B oscillates with respect to time.
Without looking to quantum electrodynamics that I don't know at all, let's say I have such a wave with a huge amplitude. I.e. the E and B fields are really strong. Does that mean that the EM wave occupy more place than a similar EM wave but with a low amplitude?
In fact I'm not sure whether the EM wave can be pictured as a line or as a 2 orthogonal "sine functions" in the 3d world. If the latter case is correct then a bigger amplitude seems to imply that the EM wave indeed occupy more place than a EM with a lower amplitude. My problem arises if say I have an enormous amplitude of E and B and that the frequency of the wave is about [tex]10^{-6}Hz[/tex]. It could be possible in this example that in a time of about [tex]1/10^{-6}s[/tex], the space perturbation (the EM wave traveling) can reach say a distance of about 300 000 km from the source which is about [tex]10^{6}[/tex] times faster than the speed of light which is of course impossible. I understand that in the direction k the speed of the wave is c, or the speed of light. But I'm not understanding if the amplitude of the wave is related to the wave's place in the 3d world.