Can you have EM radiation at any frequency or only those present in atoms?

Can you have EM radiation at any frequency or only those present in atoms?

 

Any, I should think, because a given frequency can be Doppler-shifted.

I would guess that you would need at least both of velocity and temperature to be quantized in order for EM frequency to be quantized???

I am talking about in the same reference frame ie where there could be no doplar shift due to relative movement. No sure what you mean by the second sentence.

Can you have EM radiation at any frequency...

 

Yes

No sure what you mean by the second sentence.

Everything radiates EMF EMR with frequency proportional to temperature, I think. I figure that if EMR had only discrete possible values (quantized) then it would imply that things could only have discrete temperatures. Neither is true, and my argument is probably invalid anyway.

Edited March 17, 201213 yr by md65536

<br />Everything radiates EMF with frequency proportional to temperature, I think. I figure that if EMR had only discrete possible values (quantized) then it would imply that things could only have discrete temperatures. Neither is true, and my argument is probably invalid anyway.<br />

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No i dont think so I thought the frequency stayed the same.

for example certain thing emit a certain light ie neon blue

ie in the flame test strontium is red.

 

http://en.wikipedia.org/wiki/Flame_test

No i dont think so I thought the frequency stayed the same.

for example certain thing emit a certain light ie neon blue

ie in the flame test strontium is red.

 

http://en.wikipedia....ermal_radiation "All matter with a temperature greater than absolute zero emits thermal radiation."

http://en.wikipedia....isplacement_law "Wien's displacement law implies that the hotter an object is, the shorter the wavelength at which it will emit most of its radiation"

 

So my last post wasn't very accurate. Anyway, since thermal radiation occurs over a range of frequencies, continuous temperature need not imply continuous EMR frequencies. But I'm pretty sure the frequency of thermal radiation isn't quantized! ??? Anyway DrRocket knows what he/she's talking about more than I do!

 

 

Edit: I was curious about what you wrote---haven't dealt with this since high school but it sounded familiar!... and found this: http://en.wikipedia.org/wiki/Emission_spectrum "Although the emission lines are caused by a transition between quantized energy states and may at first look very sharp, they do have a finite width, i.e. they are composed of more than one wavelength of light. This spectral line broadening has many different causes."

Causes: http://en.wikipedia.org/wiki/Spectral_line_broadening#Spectral_line_broadening_and_shift

Edited March 17, 201213 yr by md65536

The blackbody (i.e. thermal) spectrum is continuous. You really can't have everything in the same reference frame because of thermal motion.

 

 

Edit: I was curious about what you wrote---haven't dealt with this since high school but it sounded familiar!... and found this: http://en.wikipedia.org/wiki/Emission_spectrum "Although the emission lines are caused by a transition between quantized energy states and may at first look very sharp, they do have a finite width, i.e. they are composed of more than one wavelength of light. This spectral line broadening has many different causes."

Causes: http://en.wikipedia.org/wiki/Spectral_line_broadening#Spectral_line_broadening_and_shift

 

Emission spectra are still considered as quantized, even considering line broadening.