Energy of a Light Wave Question

[thomas reid]

I heard it said that electromagnetic waves have energy within them.

Is that true?

And, if so, what kind of energy is it?

I don't think it would be thermal energy.  I don't think it would be potential energy.  What is it?

Thank you.

[swansont]

Yes.

Electromagnetic energy, since they are EM radiation. Kinds of energy are largely a labeling convenience for us, rather than anything fundamental.

[studiot]

Yes EM waves have energy.

In the widest sense (of PE) it is a form of two potential energies which are periodically interchanging- hence the frequency of vibration.

Potential energy can be taken in the narrow mechanical energy sense, which you are probably thinking of, or the wider sense of energy stored in a field such as (in this case a magnetic field and an electric field).

[studiot]

1 hour ago, swansont said:

Yes.

Electromagnetic energy, since they are EM radiation. Kinds of energy are largely a labeling convenience for us, rather than anything fundamental.

I thought about this simpler version of just saying that EM radiation is a form of energy, and swans cross posted it whilst I was thinking.

 

[swansont]

51 minutes ago, studiot said:

I thought about this simpler version of just saying that EM radiation is a form of energy, and swans cross posted it whilst I was thinking.

 

And the thing is that thermal radiation (e.g. blackbody emission) would be both EM energy and thermal energy. Some people might label it as kinetic energy. It's just labels, though. An individual 10 micron photon doesn't know if it came from a thermal source or not.

[Bender]

It is often simply labelled as "light energy".

[J.C.MacSwell]

On 2/2/2018 at 10:41 AM, swansont said:

And the thing is that thermal radiation (e.g. blackbody emission) would be both EM energy and thermal energy. Some people might label it as kinetic energy. It's just labels, though. An individual 10 micron photon doesn't know if it came from a thermal source or not.

Or what frame it is 10 micron's in...so taking it further it really is not aware of how much energy it has...just out there blissfully playing the field.