Is there a difference between magnetic field and magnetic wave?

[Jerryt12]

if so, please explains.

[ajb]

An electromagnetic wave is a configuration of the electromagnetic field. Specifically they are solutions to the electromagnetic wave equation.

[Jerryt12]

so are you saying that both are the same?

[ajb]

Think about an oscillating string. This gives an example of a transverse wave, much like an electromagnetic wave. In the case of the string, the string itself is "rippling ". For the case of the electromagnetic wave, it is the electromagnetic field that is "rippling".

[Jerryt12]

So what you're saying is electromagnetic wave is simply a configuration that shows the oscillating string, and electromagnetic field shows the movement of the wave?

[ajb]

So what you're saying is electromagnetic wave is simply a configuration that shows the oscillating string, and electromagnetic field shows the movement of the wave?

 

No.

 

What I mean is a mechanical wave is a "ripple" of some material, say a string. Or say waves on a pond when you throw a stone in.

 

An electromagnetic wave is a "ripple" of the electromagnetic field.

[Jerryt12]

electromagnetic field is the medium of electromagnetic wave.

 

if that is true, without electromagnetic field, there will be no electromagnetic wave.

 

every object, gas, liquid have their own magnetic moment and electric field, thus creating a electromagnetic field so light can travel through.

 

If what I just said is true, how can light travels in a vacuum when there is no electromagnetic field present?

[sr.vinay]

Nice argument.

But what I think is that the electromagnetic field, as we've learnt is continuously alternating.

This should mean that the fields by themselves propagate along with each other, thus proceeding till the energy is sufficient.

[Jerryt12]

Just to make sure, what you're saying is the field propagates into the vacuum, thus making it possible for light to travel through?

[Simpleton]

Finanly had a chance to read some posts and this one is making me have a big grin on my face. I "think" that in the current view, light or a photon can travel without any help and does not require a medium to travel and stay alive.

"Personaly", I find that difficult to believe and like it the way you understand it.

Edited March 29, 2010 by Simpleton
spelling

[Jerryt12]

Dear Simpleton,

 

I once thought the way you do because light travels the fastest in a vacuum, thus making that hypothesis very supportable. But If what you said is true, then electromagnetic wave will be able to propagate without electromagnetic field. If that is the case, what is the relationship between electromagnetic wave and electromagnetic field?

[Simpleton]

Of course, I stand to be corrected. Keep in mined my name.

A magnet will give you a stationary magnetic field, getting weaker with distance.

The vacuum, space, the universe, everything, is an ocean of mostly electro magnetic waves. All of them moving at the speed of ligth comming from all directions and going in all directions.

[ajb]

If what I just said is true, how can light travels in a vacuum when there is no electromagnetic field present?

 

If you had a true vacuum, so no matter nor fields then there would indeed be no light. (Often by vacuum you just mean no sources, not no fields.)

 

But that is not what we have physically around us, even classically. The electromagnetic field permeates all of space.

[sr.vinay]

Just to make sure, what you're saying is the field propagates into the vacuum, thus making it possible for light to travel through?

 

Light is a form of energy. Energy is radiated out with an initial velocity in the form of packets called photons. Same way, all the radiations are energy. To explain how these propagate, we consider their two alternating energy fields, namely, magnetic and electric. These by themselves don't propagate into vacuum, they travel along with the path of the energy packets, so as to say.

[swansont]

Light is a form of energy. Energy is radiated out with an initial velocity in the form of packets called photons. Same way, all the radiations are energy. To explain how these propagate, we consider their two alternating energy fields, namely, magnetic and electric. These by themselves don't propagate into vacuum, they travel along with the path of the energy packets, so as to say.

 

Not quite. Electromagnetic radiation is a mechanism of energy transfer, but light isn't a form of energy.

[sr.vinay]

Light isn't energy?

Woah! Could you elaborate? I know light is the visible range in the EM spectrum. But, saying light isn't energy, that would mean you're claiming photons inexistent?

Aren't they packets of energy?

Edited March 30, 2010 by sr.vinay

[swansont]

Light isn't energy?

Woah! Could you elaborate? I know light is the visible range in the EM spectrum. But, saying light isn't energy, that would mean you're claiming photons inexistent?

Aren't they packets of energy?

 

They possess energy; energy is a property. They also possess momentum. We don't call them packets of momentum.

[ajb]

Just classically, the electromagnetic field has an energy density, you can write it in terms of the E and B fields if you wish.

 

But the field is not thought of as energy.

 

The same way a mechanical wave in a string carries energy, but you don't think of the string as being "made of energy".

[sr.vinay]

They possess energy; energy is a property. They also possess momentum. We don't call them packets of momentum.

 

Just to be clear, 'they' possess energy? So photons are entities with no mass. But, they possess properties such as energy?

[Sisyphus]

Just to be clear, 'they' possess energy? So photons are entities with no mass. But, they possess properties such as energy?

 

Yes.