Is it possible to create a magnetic field which can be seen?

• HastiM
In summary: thing... you can do is create a magnetic field and see if you can cause an electric field to oscillate with it.
HastiM
Hello,

I am wondering if one can create a magnetic field which can be seen by a human eye? I have learned that light is nothing else but electromagnetic field with a wavelength between 400-800 nm. Colours correspond to different wavelength within the above spectrum. So isn't it theoretically possible to produce a magnetic field with let's say wavelength of 500 nm? Wouldn't that imply that such a magnetic field would appear to us in some colour?

Best wishes

HastiM said:
Hello,

I am wondering if one can create a magnetic field which can be seen by a human eye? I have learned that light is nothing else but electromagnetic field with has a wavelength between 400-800 nm. Colours correspond to different wavelength within the above spectrum. So isn't it theoretically possible to produce a magnetic field with let's say wavelength of 500 nm?

Best wishes
You must learn some more introductory physics. Magnetism is another force altogether. You can't possibly be able to see it. It doesn't have a wavelength like you think.

Thank you for your answer. But a magnetic field is a solution of the wave equation, so in my understanding it should be called a "wave". Doesn't have any wave also a wavelength?

HastiM said:
Thank you for your answer. But a magnetic field is a solution of the wave equation, so in my understanding it should be called a "wave". Doesn't have any wave also a wavelength?
But I don't think you can create a wavelength of magnetism. All matter and electromagnetic radiation has waves, but not magnetism. Electromagnetic radiation is only induced from magnetism when there is magnetic flux. This wavelength is far from visible light. Let me remind you that electromagnetic waves span a massive range of lengths.

HastiM said:
So isn't it theoretically possible to produce a magnetic field with let's say wavelength of 500 nm?
When you look at a green colored object you most likely have seen a 500 nm wavelength magnetic field along with the electric field with the same wavelength. If however you want to produce a stand alone space and time varying magnetic field unaccompanied by electric field, it's theoretically not possible - Maxwell's equations forbid you to do that.

HastiM and lekh2003
@blue_leaf77: Thank you very much for your answer! I had not thought about the problem from that point of view! I must admit that I do not understand your last comment completely. Could you please explain why Maxwell's equations do forbid such an unaccompanied magnetic field?

HastiM said:
I have learned that light is nothing else but electromagnetic field with a wavelength between 400-800 nm.

Not quite. See more below.

HastiM said:
So isn't it theoretically possible to produce a magnetic field with let's say wavelength of 500 nm? Wouldn't that imply that such a magnetic field would appear to us in some colour?

I think there's some confusion with different concepts here. First and foremost, light is an electromagnetic wave. An EM wave is a propagating disturbance of the EM field, it is not the field itself.

Second, a field is a mathematical way of modeling something. The details are a bit complicated, but basically the EM field is a field that we use to model the electromagnetic interactions between particles in such a way that doesn't require us to place a test charge at every location that we might be interested in and then doing a calculation. This field is not capable of having a wavelength. Wavelength is a term that just doesn't apply to the field itself since the field is not a wave.

HastiM said:
Could you please explain why Maxwell's equations do forbid such an unaccompanied magnetic field?

Our experiments and observations have shown that a varying magnetic field is always accompanied by a varying electric field, and vice-versa. Not only that, but we've also discovered that the electric and magnetic fields are just slightly different versions of the same thing. That "thing" is the electromagnetic field. You might set up a magnetic field in your lab, but if I come blazing through your lab at a super high velocity, I'll actually see your magnetic field as an electric field instead.

This observation that the electric and magnetic fields are linked to each other leads to our equations forbidding a varying magnetic field without an accompanying electric field.

HastiM, davenn and anorlunda
lekh2003 said:
You must learn some more introductory physics.

Pot. Kettle. Just sayin'.

There's a lot of misinformation in this thread. If I have a magnetic field pulsed at an optical frequency (however I manage to do that), it absolutely will produce visible light. I'm not sure where the "no electric field" part came in, but the oscillating magnetic field will itself produce an oscillating electric field. You won't have one without the other.

davenn
lekh2003 said:
But I don't think you can create a wavelength of magnetism.
EM waves involve varying Electric and Magnetic Fields. The one always goes with the other. The only 'visible' EM waves involve very fast changes of E and H fields at around 600THz (Terraherz). Waggling a magnet around can never do that. The wavelength of a wave that changes at, say once a second, will be 3x108m.

1. Can a magnetic field be visible to the naked eye?

No, a magnetic field is an invisible force that cannot be seen by the human eye. However, its effects can be observed through the movement of magnetic materials like iron filings.

2. Is it possible to create a magnetic field that emits light?

No, a magnetic field itself does not emit light. However, when a magnetic field interacts with charged particles such as electrons, it can cause them to emit light. This is known as electromagnetic radiation.

3. Can a magnetic field be made visible through a special device or tool?

Yes, there are tools such as magnetic field viewers or magnetic field sensors that can detect and display the presence of a magnetic field. These devices use different technologies such as iron filings or electronic sensors to make the magnetic field visible.

4. Are there any naturally occurring visible magnetic fields?

Yes, there are some naturally occurring visible magnetic fields, such as the magnetic fields produced by the Earth and other celestial bodies. These fields can be observed through the movement of compass needles or auroras.

5. Is it possible to create a magnetic field that can be seen by the human eye?

No, a magnetic field is a physical force that cannot be seen by the naked eye. However, its effects can be observed through the use of specialized tools or by observing the behavior of magnetic materials in its presence.

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