I can't seem to find any numbers on this. How big are EM wave amplitudes? I am primarily interested in the ratio to wavelength.

And how come amplitude is irrelevant to wave energy? It seems dependant only on the frequency, but however amplifying a wave sure does expand energy so where does this energy go if not into the wave?


Are the EM field always perpendicular to each other. Material on the net is confusing. I've often come across drawings of circular waves and tilted waves mixed up with polarized waves etc.. Can they actually be circular? And can the magnetic field not be perpendicular to the electric field? That kinda seems silly to me.

I can't seem to find any numbers on this. How big are EM wave amplitudes? I am primarily interested in the ratio to wavelength.

Do you realise that the amplitude and the wavelegth are in different units?

If you want the amplitude of, say, the electric field, look up the expression for the power of the wave, in terms of the amplitude.

And how come amplitude is irrelevant to wave energy?

It isn't. I think you may be mixing up the quantum picture with the classical one.

Are the EM field always perpendicular to each other.

Yes. The electric field and the magnetic field at any point in free space for an electromagnetic wave must be always at right angles to each other and also to the direction of propagation of the wave.

Material on the net is confusing. I've often come across drawings of circular waves and tilted waves mixed up with polarized waves etc.. Can they actually be circular?

Are you talking about polarisation? The direction of polarisation of an electromagnetic wave is the direction the electric field vector points. A circularly-polarised wave, for example, has the electric field vector rotating in a circle as the wave progresses. At any point on the wave, however, the magnetic field is still at right angles to the electric field.

yes, i thought i have confused the energy of a photon as in quantum physics which doesnt seem to involve the amplitude - which is weird. that would mean that amplitude decides on the number of photons rather than their energy?

also, can they somehow be shifted in phase? the magnetic and electric field?

how does circular polarisation work? i can understand that something can polarise a wave, rotate the E field plane around the z axis somehow. but how does this rotation of the wave along the z axis keep on going after the EM wave has left the polarizing medium?

yes, i thought i have confused the energy of a photon as in quantum physics which doesnt seem to involve the amplitude - which is weird. that would mean that amplitude decides on the number of photons rather than their energy?

The intensity of light in a quantum picture is determined by the number of photons emitted per second and the energies of the individual photons (which depends on their frequency).

also, can they somehow be shifted in phase? the magnetic and electric field?

Yes.

how does circular polarisation work? i can understand that something can polarise a wave, rotate the E field plane around the z axis somehow. but how does this rotation of the wave along the z axis keep on going after the EM wave has left the polarizing medium?

Electromagnetic waves are self-supporting. That's the whole point. A changing electric field creates a magnetic field, and vice versa. If you start up a circularly-polarised wave, it will propagate through space and remain circularly polarised.

is it plausible that each section(between two amplitudes) of the wave is created at a different angle around z and they propagate as such through space? each section remains at its own angle, but as the following section were "launched" at different angles they seem like the whole wave is circular?

how do the phase shifted EM waves work? if the magnetic field causes the electric field in an orthogonal plane and so on, how can they become phase shifted? that would mean they are two separate fields which carry themselves and do not care about each other?

is it plausible that each section(between two amplitudes) of the wave is created at a different angle around z and they propagate as such through space?

If I understand this correctly, that is what happens.

how do the phase shifted EM waves work? if the magnetic field causes the electric field in an orthogonal plane and so on, how can they become phase shifted? that would mean they are two separate fields which carry themselves and do not care about each other?

The magnetic and electric fields are always in phase with each other. The phase of the entire wave simply determines the amplitude at the point of emission.

With circularly polarised light, the phases of the x and y components of the electric field are separated by 90 degrees (and so are the magnetic components).

ah, so everything still works as it should and im not losing my mind.

phase shifting only means shifting the E field which will always shift the B field, so the wave is "phase shifted" compared to an original wave.